Ambient air... my daily consumption on my reclaim has gone from 3kw/day start of October down to 2.2-2.5kw/day currently. It does jump about a "lot" with ambient air going from 15deg to 25deg. 2 showers a day & some washing up. Best thing is that even on a cloudy day with a 4.5kw solar system, its 100% free energy at its 1kw/hr consumption!
From 3 kWh/day down to 2.2 - 2.5 kWh/day, supplying you free domestic hot water even on a cloudy day from a nominal 4.5 kW solar PV system is very nice. With a power draw of 1 kW it means the heat pump needs between 2 to 3 hours of operation in your particular use case and the solar system seems well matched to your needs.
@@sietuuba yes, on most days its enough to cover the hot water & do some other low current draw activities. However that may change in winter - i'll be adding more solar soon :)
@@GeomancerHT They are quite common depending on where you are, new builds some councils mandate a solar water install. You are 100% correct - they're the most efficient way to heat water - however, they're not the most efficient use of roof space - thats the thing. If you have loads of roof space - its the best option. If you have limited roof - you're better doing solar, so that the other 1/2 the day its producing for you.
As a canadian its very interesting to see all your utilities placed on the outside of the house. Your breaker, water tank and drain pipes being exposed give me the hee·bie-jee·bies. Must be nice to stay above freezing year long :)
HA ya in Montana everything is in the basement but in Arizona everything is outside I do miss the basement but in Arizona i get what I call perma hot dirt the water in summer is never below 90F
In Canada the cold supply line would freeze and you'd have to burn way more gas tokeep the water hot at -20C ambient. The supply line comes in the house at well over a meter deep and the main water pipes (supply, sanitation and storm) run at a number of meters deep in the street, all to avoid freezing up.
Another fun fact... the bigger the tank, the more efficient its heat retention (volume vs surface area). This also allows you to program the controller to not run the heat pump during certain hours (e.g. avoid high time-of-use electricity rates), and not have to worry too much about running out of hot water. I have my heat pump water heater programmed to not run between 4pm-9pm and its never been a problem for us. Our heat pump water heater uses around 4kWh/day. That's about the minimum. But I also have a hot water recirculator and the pipes are pretty long. When I run the recirculator on a timer in the morning it adds 2kWh/day for 6 total. But its better doing that than wasting water witing for the hot to get to the shower. Your 2.83kWh/day is pretty awesome. That is a number to be proud of! I mean, compare it to the solar output. Our upgraded 5kW solar system produces 30kWh/day+ during the summer and around 16kWh/day in the winter. And the water heater is using just a tiny bit of that... I'm a happy camper! -Matt
Totally on point; big enough heaters are indeed useful for split tariffs. I've got a Stiebel Eltron SH120S in my flat, retrofitted with a ESP8266 based controller that allows me to turn it on and off from my home automation system. It works from 4 till 7 (end of the night trough), then 13 till 16 (afternoon trough). Six hours a day, though the night trough starts at 22. The reason why I don't want to turn it on in the evening is exactly what you mentioned: stand-by losses. Minimizing the time it's hot means minimizing the energy losses, though that tank is already real damn good in this regard (around 1kWh per day at 60 deg C). Oh, and @EEVBlog finally got some insulation on these pipes now! I wonder why it wasn't there with the gas heater.
@@KeritechElectronics heh yah, I noticed the lack of insulation too but forgot to comment on it. The copper pipe is a big radiating surface. I forget what the wattage per foot is (copper pipe, 125F water, 70F air), but it is not insignificant. Multiply by 24 hours a day, 7 days a week... definitely not insignificant.
You can set the mixing valve lower without fear of using more hot water, it will just mix in more cold at the valve as opposed to your tap. The only difference is the maximum temperature of "full hot" at your tap will be lower (which is what you seem to want).
As long as the water temperature (and usage pattern) is ower legionella bacteria survival criteria. According to wikipedia "At 50 °C (122 °F) - 90% die in 80-124 minutes" en.wikipedia.org/wiki/Legionella#Heat
@@AnatoFIN the hot-cold mixing happens after the tank. The tank is heated to 60+ degrees at least once a week. So no legionella risk by changing the tempering valve setting.
@@-vermin- Legionella can grow in the pipes. I would prefer if temperature was high enough to inhibit Legionelle growth from the tank trough the tempering vale to the tap. I admit I'm no expert on this, but at least in Finland, ministry of environment regulation (1047/2017) specifies that hot water must be over 55°C everywhere in the hot water system to inhibit Legionella bacteria.
I set my heat pump tank (yes, my tank got its own heat pump as part of it) to 54 degrees celsius, with no anti legionella cycles because there's no need to go fast kill when the tank ramps up to slow kill twice a day and stays there for hours each time. And I discard the cold part from the pipe. I have it in a roofed outdoors area, kind of like a porch. I want to move it to the back garden washroom though, to reduce pipe length and act as a forced air intake into that unheated space. Valencian village, so even though air freezes in winter it's only in the night and usually less than two weeks, so no time for pipes that are being used to freeze, especially with insulation on them.
I installed a heat pump water heater and I'm thrilled by it. I keep it on heat pump only mode and it does great. The water heater that came with the house was oil fired, and it wasted a lot of oil. Same with a gas unit, heat rises up through the flu pipe while it's off and convection cools the tank.
In the US, the whole unit is typically installed inside so it does double duty cooling and dehumidifying the air, along with heating the water. That makes a lot of sense in the warmer southern climates. I was surprised to see yours mounted outside. This was really interesting. Thanks for sharing.
Interesting! How does that work in winter? Presuming the outside temperature does sometimes go below a comfortable room temperature, you’d be heating and cooling at the same time when the hot water heater is running. Or is there some kind of valve to send the cooled air outside in that case?
RickMakes I don't know if that is a regulation down under, but I have often wondered that myself. It makes no sense not to be trying to maximise the surroundings. How can rain pelting down on a hot water system be help its efficiency?
@@DodgyBrothersEngineering usually there’s still roof overhanging the unit, and like Dave pointed out, it’s so well insulated it feels room temperature on the outside anyway
I like the design of that. Here in the US they are a combined unit (at least the common residential units) with the compressor assembly sitting on top of the tank. I suspect the remote unit like that could be a little more efficient since you probably have a good bit more area for heat exchange. As it is, I'm using about 1/3-1/4 less power over our old resistive heater. (Varies by the temp in my garage). Still completely happy with the purchase, after the local rebate we got the unit will have paid for itself in under 2 years! Given our current electricity rates, we're paying anywhere from $.30 to $.60 USD a day for hot water. That would have been between $1-2 usd with the resistive heater. Last week we averaged 4.2kWh /day power usage on the unit, and that's with 38-45 deg F air supply temps. This past summer when it was over 90f in the garage we were down near 3 kWh /day.
Same here, I love my hybrid... I keep it on heat pump only. I had an old (1995!) oil fired cylinder and it was a huge waste of money and oil. It ran more often than my hybrid unit which pulls 450W. I left it in the house for a year after I bought the home, and then I kicked myself when I saw how fast it went through 125g of oil!
@@USA-GreedyMenOfNoIntegrity Quite cold, but who cares, its the garage. Makes it a bit nicer to work out there in the summertime though. The garage is to the side of the house as opposed to under or above, and the walls are well insulated between there and the living spaces. I'm also planning on ducting the intake to the attic which is directly above the unit, so it will have access to much warmer air temps almost year round.
I guess if you are always refrigerating your home and it never really freezes then it makes sense to have your hot water outside. Where I live, 60% of the year I'm heating my house, don't have AC, and we definitely get well below freezing. If a little heat gets out of the hot water tank, it just heats the house so it isn't wasted.
Consider adding some insulation to the overpressure valve since it is hot losing some of your stored heat, even add more insulation to the exit hot water pipe.
OK, I'm about to start watching the video as a month ago I had installed a Reclaim heat pump and Earthworker 315litre storage. Two weeks ago we got the 6kW solar array done and set the Reclaim to mode 4 (only on between 10am and 4pm). It's been using 1kW between 10am and 11:30am-midday and so far I'm extremely happy with it. Looking forward to what you discover with your own system!
Great series of videos. Must watch for anyone considering to switch. You can't ask for more than this: an example of a system installed with costs compared over a year.
I love your engineering breakdowns. I have a Rheem 50 US gallon heat pump water heater set to 120F or 49C and your KWh usage numbers almost exactly match my KWh daily usage. There are no mixer valve requirements here. It’s located in my garage, so it reclaims the heat from my and my wife’s cars. I am jealous that you have a stainless steel tank. Here it’s all about planned obsolescence, meaning a glass lined steel tank, UG…
I found similar performance with my 415L heat pump in Sydney. After 6 months of investigation, I figured out the real issue, built my own controller and it now uses around 1kW/h per day. You are getting too much reheating of hot water due to your oversized tank, which is lowering the COP.
yep, thats what i thought, he is wasting too much hot water every day, as he is not using it, and the tank is oversized for his house really, and its costing him to reheat it every day. But the prices in nothing, as its not really noticeable to him, as he is getting energy from his solar.
With low water usage, the top half of the tank will be warm and the bottom cold. When the heat pump runs it will heat up the colder water at maximum COP, while the warmer water will be at much lower COP. You get surprising good temperature separation of hot and cold water in a tank. The thermal interaction is quite complex and too long to discuss in a comment. If you want the full details you can read about my solution on the news site HACKADAY, search for HEAT PUMP and find the article written by Bryan Cockfield.
Dude; great work as always, thanks :) One point, and I know that you already know better: I would like to clarify for the benefit of any who are concerned, but not necessarily so conversant with energy, and especially within the wider political/environmental context.... Your comparisons between the actual water heating apparatus is of course absolutely correct, BECAUSE you are producing your own SOLAR derived electricity. For anyone using electrical power generated from a mix of primary energy sources, then to get a fair account of the overall energy consumed, then appropriate adjustments would needed to be included, for example, for coal fired generation:- 100 GJ (coal) in for 35 GJ (Electricity) out; along with the corresponding overall reduction in system efficiency and increase in overall environmental load (ignoring overall "embodied" energy considerations).
CO2 refrigerant mate, that's cool! (or Hot I mean!) Really says something about the climate when you have the hot water tank OUTSIDE, jeez you aussies! I think your PTC element calculation is spot on, that's more or less what I measure on our 200l hot water tank in the basement split between two apartments, so 3 adults and one child. (numbers from Norway for those playing along at home) Recently I have been looking at a hot water tank with a heat-pump installed on top from Vaillant, it uses an R290 refrigerant I think, however for the life of me I just cannot get hold of any useful data for my region. Average yearly temp here is 7 degrees Celsius, so not particularly cold, but quite an expensive investment without knowing potential savings.
You are certainly building an excellent system in your home. Fair play to you. These videos are fascinating, seeing how your slowly improving the energy efficiency of your home. When it get to winter in 7-8 months time where you are, you should do an update in how your heat pump is working in your coldest conditions where you are. Have you say, your energy prices are so low, you do not appreciate just how low your energy prices are where you live, being in sydney where alot of your energy prices will be subsidised by your gov to attract investment there. All major cities have this advantage to live there, to draw investment and workers there. If you can, you should do a series of videos on all your energy resources in your home, and show people how energy efficient your home is now, and break it down into segments. Did you get your battery backup for your solar panels yet?
I’m a sparkie in nsw. The pcb on the heat pumps fail all the time, and generally the warranty on them is only 2-3 yrs on the board but 10yrs on the tank. I’ve ended up replacing them back to element heaters as the price doesn’t suit most people for repair/replacement boards. Hope you have better luck but you would have been better with an element heater and a day time timer
Measure that temperature again to see if it was not a Fluke! Ha. Arthur looks nice. I got a tempering valve on my hot water system with an electric storage heater... Mighty useful! They're not standard here in Poland, but I highly recommend them. Apart from the high-ish COP 5 claimed by Reclaim, the real deal data loooks nice and I like that you state the limitations of your methodology, and how they can affect the tests. Tank stratification very nicely explained!
Thank you for the detailed breakdown! We're in a similar boat as the one you were in; we've only the tankless as out last gas appliance. In the whole last year, we've used 13,861 kWh of electric, and ~3600 kWh equ. of gas. The kicker is that with solar/batteries, the electricity cost $.0012/kWh, totaling $16.50, and the gas was $289 or $0.08/kWh. It's amazing to me how much more expensive gas must be in Australia. I figure our daily kWh, was 9.8 where yours with gas is 12.8. So perhaps our usage with this setup could get down to ~2.14 kWh/day (I'd optimistically figured it would be below 2). So if our electricity rate stays roughly the same, we'd pay less than a single dollar for a little under 800 kWh in water heating. That sure would beat the nearly $300 a year we're paying now! Lol
Depending on how good the heat pump is, if it is one with backup thermal elements you should try turning those off (its usually a configuration option) and see how well the heat pump does just by itself. Given where you live, it should work quite well. I wound up getting a SanCO2 heat pump water heater. No backup heating element. Separate outside unit and in-basement 80 gallon steel tank. Its been wonderful. This particular model is designed to heat the water up above the biological survival temperature, e.g. 155F and higher, and has a mixing valve on the output to bring it down to something reasonable for the house hot water pipes (e.g. 125F). Hence also why the tank is steel. And since there is no heating element inside the tank, it is literally just a steel tank with some valves and insulation and there isn't a whole lot that can wear out. It should last a very, very long time. So far the system has been wonderful. We have never run out of hot water. In fact, even if we use most of the tank the water never actually gets cold because the heat pump's water heating loop emits directly into the top of the tank. Takes water from the bottom and runs it through to the top. Consumption is around 4kWh/day. If I run the hot water recirculator on a timer 15 minutes a day, consumption increases to around 6kWh/day.
It always amazes me when I see water products, like washing machines, and water heaters outdoors. I live in Colorado, and it will be -9 F on Thursday, for a high. Everything that can freeze is indoors.
We're thinking of moving away from our gas hot water system and stove as well. Unfortunately, since our (newer than yours) Rheem had the bottom rust out of the tank we got a far more efficient "on demand" system as a replacement, however that was before our solar panels were installed so it's still relatively new. Downside will be that without a battery we can never have hot water production during a blackout (the only benefit of the old system) or use the stove.
Nice! What a coincidence, I have a Reclaim system in my garage that I’m just about to have installed! Looking forward to using my solar power directly for hot water instead of exporting it for 6c and then buying it back for 19c/kWh into my old rusting conventional system!
Your figures are very similar to mine after conversion. Had an on demand gas at the old house, an old off peak tank at the current house and converted this to a Rheem 320L heat pump unit. We are on a 5 kW (rated ) solar system. South Aus, near Port Wakefield. Instant reduction in our power bill. I recommend this to everyone. Our unit cost $4000 installed. I'm keeping my old tank. Going to set it up as a standby solar cell only heater for outdoor hotwater for washing the doggies.
I understand that in Australia there isn't a lot of need for heating, but here in Finland heat pumps of various kinds are used extensively for heating buildings and water also. The most effective ones use drill wells where heat is transferred from the soil by a circulating fluid, such as ethanol, but the initial cost is high, about $10,000-$20,000 for a single family house. A cheap alternative is a heat pump which extracts heat from outdoor air, and those are as cheap as $2,000, including installation. Their disadvantage is that efficiency falls when temperature gets cold, and they completely stop producing heat at -30..-25 Celsius.
Looks good on the install of Arthur, and they did a pretty good job on insulating it. Looks pretty good, and only criticism is the airflow around that evaporator, should be a little further out, along with the AC units, to get good airflow around them, which does make a big difference to off coil pressures in the system. The R744 is a good refrigerant, though the pressures at the top end of the system are scary high, 40 bar plus, but at least a failure is just going to be noisy, and pop the TP valve for a few minutes as it vents. Should have had a measure of your hot water use, water meters are pretty cheap (funny though the last one I bought the brass was cheaper than the plastic, probably because the plastic ones are sold at a massive mark up, as they do not get stolen) and work well as baseline for water use (more data better, allowing you to see split of home water use for hot water, cold water and garden, which likely is the biggest use) and power use. But yes you will be saving money off the bat, essentially whatever the gas bill is, of which I would say most went to keeping that pilot flame lit all the time, and the gas usage would probably be overall less than the pilot flame use. As to pipe temperature drop, it is lowest at full flow, do another test with low flow, like you would use to wash your hands, and compare again with the radiated heat in the roof, easily going to be 10C at low flow, where the water has longer to lose heat in the pipe.
I just found a shower head flow meter and temp meter on ebay for $20. Didn't even think to look for that. I didn't want to screw up the new copper pipe work just to install a proper flow meter. EDIT: Nope, the ebay one is just a temp meter, uses the water flow to power it.
@@EEVblog Just a thought, I used water meters at a previous job so I could monitor water use on the ion exchange resin, and also budget the cost per batch.
I'm not sure I'm that keen to get exact data. I'd want it logged as well, and then I'd also need a automated temp loggers as well. I'd be doing Reclaim's R&D for them at that point! They should just publish some characteristic curves.
@@EEVblog They probably have not got the data other than under lab conditions, no real world data really. Easy enough to add in the data logger and water use monitoring, as most water meters have a built in magnetic wheel that generates a one pulse per 10l signal that you detect outside the case. Simple data logger integrated into the solar system data would not be much, just 4 channels to record ambient temp, inlet water, outlet water and pulse count.
@@EEVblog Incidentally, as a experiment go out tonight with your thermal camera, just before bed time, and long after showers are done, and look at the tank and heat pump, and look for the hot spots. Those are all heat leaks, that all are the majority of loss from the system. Add more insulation to cover those losses, which are all the exposed copper pipes on the hot loop and the overpressure valve, and you will see a few minutes less runtime on the system, as the majority of the static thermal loss is via the connections and pipes conducting heat away. Cheap upgrade that makes a big difference, especially on electric units, where this is around half the energy loss on the modern ones, the rest coming through the cavity for the electrical connection, and a small amount from the insulation around the tank. Incidentally make a calendar note to change the sacrificial anode on the unit in a year, order 2 spares now (while still available), and you can then extrapolate anode wear from the inspection, so you can roughly estimate lifetime. Your anode will wear first, then the tank will corrode through, though the heat exchanger is likely the first part to fail. Anode typically lasts 2 years or so, depending on the water softness, and when it is gone your tank is the sacrificial anode instead. By me a new electric heater is only $400, so cheap to replace with the identical one.
I would be very surprised if it's actually more efficient in colder weather. Basic thermodynamics says the highest COP should be at the highest ambient air temperature.
According to the designer (I contacted him), yes it performs better in colder climates. With C02, the colder in ground water temp to higher the COP. But also the higher the ambient temp the higher the COP.
@@EEVblog to prove this to us you should make a video about the phase changes of multiple refrigerants and their resulting maximum efficiency temperature deltas! :P
@@shittubes What the designer was saying is that it performs better with lower cold-water temperature. But it also performs better with higher ambient air temperature. Therefore, Dave is getter poor performance, as he is only using a small amount of hot water tank capacity. So the system has to reheat a lot of warm water already in the tank at a greatly reduced COP. My simmilar system only uses 1kW/h per day.
@@SqueakySnow i agree 100%, given the placement of the valve that goes from the tank to the heatpump, if he doesn't use most of his tank's capacity that water will be way too warm for getting to any high COP. where i live there are also other more elaborate systems with multiple valves at different heights to optimize this slightly, but i guess it's just not needed with this abundance of solar energy in australia
@@EEVblog that makes sense that the COP would be higher with a colder water temperature. But I think you'll still use more energy overall, heating cold water than warm water.
I'm wondering if you were underestimating the amount of hot water you were consuming from the old gas system. The one time my gas system went out it took like under an hour to heat the whole tank from ambient to hot. So you wouldn't run out of hot water unless you all had long hot showers back to back, as it is heating the water at a reasonable rate compared to your usage. As opposed to your new system which is entirely stored hot water at the time that you are using it.
I’ve got solar panels and an immersion heater for hot water. There’s a controller which uses PWM to vary the power going into the heater to match what would have been exported. This is great because it can use anything from 0 to 3kW to exactly use the right amount. There’s a late evening boost in case the sun didn’t shine enough. Wonder if the extra efficiency of a heat pump would be worth it here… also is it possible to vary the power consumed to match that being exported, like the immersion heater? Most heat pumps have inverter control now but can that be coupled to the export power?
I need one of those temper valves! I'm up in PNG and have the roof mounted solar water heater. Every few months I go up and pressure wash the dirt and junk off the panel and the next week the water is absolutely scalding!
The diagram @33:15 is showing lower COP at lower temperatures for both refrigants, so the efficiency in colder tasmania should be worse, not better. Perhaps they measured efficiency through a heat wave..
Oh that's interesting it's two pieces! Over here in the US we just started pushing for more efficient water heaters although they were fairly well efficient already. as nobody likes their hot water getting cold that they paid for. The units now have everything in the top foot and a half section of the water heater. They also include electric back up or/and boost. And there's a temperature range adjustment because well bathing is one temperature and sanitization and commercial kitchens or another so you have to find a setting for your liking and safety. within that range you also have to keep in mind more energy usage for higher temperatures. We have what is called a mixing valve same thing as you're calling a temper valve. It's not used very commonly as it's more normally a matter of setting the temperature on the water heater. However in places where you would need extra extra hot water and not so hot water say sharing a industrial kitchen with a bathroom or similar. It can be also used to prevent pipe freezing by circulating some of your hot water back into the cold water lines on outside wall sections of additions.
To measure cop. Turn off heater. Remove tempsensor. Flush out all old hot water. Start heatpump and log electrical energy until "cold out" reaches 60°C.
Yes! It's so out of the norm for me to see water piping and appliances outside!... But even in the US (where I am) it is also the norm in warm climates... But it was already -12c the other day where I live, and winter is just getting started, so I can only dream about that!
I use direct DC from PV to electric hot water heater elements. I am working on a project to divert some of the input dc from PV before it gets to the controller ( on separate battery system). Then any excess not needed to keep the batteries full will go instead to heat the water - no conversion losses by controller or inverter.
@@AttilaTheHun333333 Critical failure of the pressure vessel. My grandmother had one go through her first floor. Didn't make it through the roof, but damaged the kitchen that was sitting above it.
Realy liked it, wondering why this is not a standard for residential house, or apartments. It could even reduce cost of heat pumps if they are produced in huge numbers.
You could possibly fit a recycling pipework set up to the tank to reduce the cold spot effect at the bottom of the tank ( brings to mind Appollo 13 stirring the tanks). Also the effect of ground cold on the mains water feed will affect how much power you use to warm the tank.
My gas bill tells me how many TH I have used over the month. I read through the utilities website and found (TH) is Therm. Therm is apparently 100 cubic feet of natural gas. 1 Therm is also 100,000 BTU or 105,480,400 joules. I was digging into all this to try and figure out some of the math like you did as a possible comparison of different water heating choices. I then remembered this exercise is almost pointless because I not only have a gas water heater, I also have a gas furnace and a gas stove.
This is a useful video because I am thinking about swapping out my solar hot water system for a heat pump. The solar hot water is great on sunny days when the only energy comes from the few watts consumed by the circulation pump. However on rainy days like today, it can chew power with a 2.3kw booster. I have a sensor in line with the booster thermostat about 30cm from the top of the tank. To take that from 45 to 53-degrees C took 4.75kWh (then the sun came out about gave me another 5-degrees for “free”). The tank has a thermowell about 30cm from the bottom for the solar pump sensor. When the tank was reading 53 at the top, the bottom was reading 51C. On a good sunny day the top of the tank can easily reach 73C. The water direct from the solar collector can be 100C+. However, just a few rainy days would put the heat pump in front.
Hi Mate, I think you'll find that if you used the full 400lt every day, your relative COP figures will be better still, much closer if not better than 5. This is because it takes about the same kWh input to heat from 20 to 45 degrees, as it does to heat the remaining 15 degrees to 60. This is due to the greater temp differential when heating at the lower temps, meaning you get better relative COP figures thrifty the first half of the heating cycle. This has an impact when factoring the volume. If you try it for a week, empty or the hot water prior to the daily heating cycle, so you're heating the full tank, not just 170lt, and redo your measurements and COP calculations, you'll find better relative efficiently and better overall COP when heating a larger volume of water.
Great video, very interesting and informative. I would like to do the same, but being in a rental I can't. Out of interest I decided to calculate our annual gas consumption in kwh to see where we stood. We have gas hot water storage, instant gas hot water in the kitchen and gas hydronic heating, our total gas consumption for the 12 months ending October '22 was 21095kwh, 58kwh/day. OUCH.
Got a 300 liter tank with a 500W heatpump on top. I have an esp8266 checking the shelly3EM power meter and if it sees more than 400W going from solar to net it switches the heatpump on. Off when solar doesent deliver of wifey is cooking or washing. Works quite well in summer and not at all in winter.
On other countries, such as Thailand where I live part time, we use tank less water heaters. One in each bathroom. They cost about $100 each. Our oldest one is a twenty year old Electrolux. Still works great. Truth be told, we only use them on cool days and there arent many of those.
In Europe we have solar systems too but for hot water we use vacuumed tubes with heat pipes in arrays of 10 to 30 pieces. Maybe if you account the solar panels efficiency per square meter the vacuumed tubes are more efficient. Plus in a no frost area you could use direct heating vacuumed tubes that heat the water directly in the tubes wich raises in an upper tank using no electric energy. Useful in no energy available environments.
I have the same tubes here in Perth WA. Its backed by an LPG fired on demand heater that only kicks in to boost the water temperature to 65C (if the inlet is below this) when a hot tap is turned on. Being LPG I run it on 8kg BBQ gas bottles. The LPG also feeds the gas hob. The warmest 6 months of the year I run on one gas bottle, the cooler 6 months I use one a month. At $30AU per re-fill my hot water and hob cooking is costing me $210 a year.
Dave, a medium sized single solar water heating pannel on the roof will give you more energy than half of the photovoltaics you've installed. In energy sources poor continental Europe photovoltaics are considered "they have more money than they know what to do with them". For europeans living in moderate climate zone with full four seasons with snow covered couple of months in the year living a house you can expect to find in their house hot water tank with 2 or 3 heat exchange coils - for solar, wood or gas burner and for a heat pump plus a direct heating element. High efficient solar heat pannels that requires pump for heat transfer fluid can heat your boiler from 5 - 8 degrees Celsius winter tap water temperature to over 30 degrees even in freezing cloudy period with short days and weeks without sun thus cut energy requirements from not free sources in half and in the summer it well produce heat more than needed.
4:26 Sure there is loss of heat from the exposed pipes. It's just that the boiler is hot enough that the pipe is maintained at the same temperature. If it is a particularly hot day, then the pipes through the roof might not lose too much heat but in winter it will be a different story.
You guys have some crazy good water down in Australia if that's only the second water heater your house has ever had. I don't know of too many places here in the US where water heaters can last that long. My dad wants to replace his gas water heater with a heat pump style as well. His water heater and furnace are in the same closet. He'll be able to use the Water heater to augment the Central Air conditioning in the summer.
Wow! Here (west coast Canada) water is soft but first gas heater lasted 11 years and worried as we are 11 years into the second. (Everyone in area has similar life spans)
@@tegra5971 There is a sacrificial rod in water heaters that needs to be replaced. If not then instead of the rod getting corroded it will start to corrode the tank. Look it up on youtube - sure there are videos explaining that. When those rods start to go bad sometimes it can make the water smell like rotten eggs. Those rods can be kind of hard to get out if the cap on them is all rusted in. I think ask this old house did a video on replacing them.
Outside water heaters are common in southern California, not so much in the Midwest. Gas in the US is measured in CCF or therms. CCF is hundreds of cubic feet; therms are CCF compensated for actual energy content. You can get gas water heaters with much higher efficiency. The one in my house in Ohio was rated for ~90% IIRC. It did have some odd things to get that efficiency. The flue shot out sideways and had a blower. The thermostat was weird: it controlled the blower, not the gas. The gas was controlled by a vacuum sensor on the flue. If the blower didn't start or was blocked, the gas wouldn't turn on.
14:15 You could directly compare the consumptions based simply on the bills and the price per unit of energy consumed (assuming the two systems are set at the same temperature). For the comparison to work though, you have to assume equal amount of cold water going in and to determine that you would need a flow meter on the inlet (as pointed out at 29:15). The bills might be higher than expected with the new system due to increased consumption. It's very easy for the consumer to assume that just because the new system is more economical on energy, then it will be fine to consume a little more hot water - but in practice it might prove hard to judge exactly when "a little more" becomes "a little too much".
First I grew up in a house with an 85°c hot water system, yes that's what came out of the taps. Secondly I just got a free heat pump hot water system at my business property due to a government program. Thirdly I live in the same city as you.
Tempering valves are awesome! Double your effective hot water buy heating the water in the tank hotter than normal and then mix down to 125 in the US. Be sure to get a spare since they do fail quicker than I thought. From experience. Mine failed closed thankfully but my wife found it not me. :(
The new plumbing standards will make a huge difference as well. The tempering valve effectively "extends" the amount of hot water you have available by mixing cold at the tank outlet so is more efficient. I'd imagine they also installed a cold water expansion valve as well which saves you from having hot water dumped out the valve (wasted energy) when the tank is heating.
The mixing valve does not affect the amount of hot water you effectively have. If you set your water faucet in the shower to keep a temp of say 45c (113f) then it doesn't matter where you mix that water as long as you mix it to the same temp. You can have a 20c and 65c supply to the shower then mix it down to 45c, or you can have a 20c and 65c at the hot water heater that mixes just a little down to 55c, then mix a little more from 20c and 55c at the shower. Either way the cold water is 20c and the hot water in the tank itself is at 65c. No matter what you do the water in the tank has to drop from 65c to 45c and where that drop happens doesn't matter. For the expansion tank, most places require it by code if you have a supply check valve at the meter, otherwise pressure could rise dangerously in the system and release the pressure release on the hot water heater.
@@2009dudeman There is efficiency loss in the piping, the heat radiates into the walls. By having an already lower temp transiting the piping through the house there is a lot less energy to lose. Hot water cylinders have always had expansion valves, but on the hot side rather than the cold side. This means that when the tank is heating and pressurising, the relief would come from the hot side, which is already heated water which is a waste of energy. Cold water expansion valves are part of the new standard so you are releasing water from the cold side instead of the hot side, so wasting a lot less energy.
@@ipullstuffapart I'm sure there is measurable loss, but whether that's significant or not depends highly on the specific system. But you generally aren't losing a lot except in the worst case. I have copper pipe, which is pretty much worst case for radiating and conducting heat from the water to the surrounding environment and even I have an almost non-noticeable difference from one side of the house to the other. I would guess maybe 1c difference off the cuff based on measurements taken over the years, but I have never measured one side right after the other, only during refit. If your house is newer and using PVC or pex the heat conduction through the pipe is minimal. The only way I could see it being worse is in our Michigan basements with copper pipe, you have ground temp air surrounding the pipe instead of internal piping with a full basement where air temps are controlled. But you can have foam wrap put on the pipe that reduces this heat loss significantly. When I put foam on my pipe the water in the line stayed hotter a little longer while sitting after using hot water but I felt no difference in water temp at the sink on the far side of the house. Legionnairea disease being a concern is the reason code prevents hot water side expansion as it's entirely possible to have water in a dangerous range for long periods of time in a hot water side expansion tank.
If you don't need 63°C turn it down to 50°C as you know and like your hot water You want to turn your mixing valve as low as possible because you mix the hot water with cold anyway to shower and whatnot. So better have a already not so hot (and not insulated!) pipe going thru your house (and loose less heat) then mixing it at the destination. You can also run the whole Tank cooler (if your heatpumnp controller supports that) Saves you energy in booth ways as the tank looses less and the heatpump will have a better COP Also you could set this thing up the way that it heats to 63°C only with excess solar power and drops down to 50°C at night (which might also get you through the night without drawing anything from the grid)
Some people are obsessed with bacteria growth like legionella, and when they are doing the regulations they may require such a temperature for any stored hot water to prevent it. In my system I have only flow heating (no storage tank) and indeed I have set it to 50degC as that is plenty hot enough.
Interesting, our heatpump hot water is all in one, the heatpump itself is sitting on top of the tank, it's pretty sweet, we run ours from 11-4 to make use of the higher air temp as much as the solar
Water flow meter also has a nice side job as a leak detector. I've got a hall-sensor based water meter reader after a broken underground pipe drained about half a year worth of water supply. I'm glad I did. Over the last year or so It has detected two minor leaks before they became a real problem.
@@mauricevandoeselaar There was no flow measurement for the old system and it was at best a guesstimate. Old system had temperature output set at 51C so a 31C above cold water input and it used 9kWh per day in average including the unknown loss through thermal insulation. To heat 170 liters by 31C you need just 170 * 31 *1.16 = 6.1kWh so unless 3kWh where lost to ambient trough that tank thermal insulation each 24h then more water was actually used.
@@electrodacus the old tank was only 170 l so it's safe to say that that is the maximum they used. And yes the old system was not that efficient. But the new system also only has to supply the same 6 kwh (its safe to assume they still use the same amount of water) not 12 because this tank is larger.
@@mauricevandoeselaar I'm fairly certain the new tank has better thermal insulation so even if larger losses to ambient should be lower. The thing is that losses to ambient are unknown thus you can not be sure that 3kWh where loses to ambient on the old tank or they where less and then he used more than 170 liters / 6kWh for water heating. In any case he uses around 3kWh now so if he has the same consumption and losses to ambient then COP is only 2 in any case less than 3 not around 4 as he concluded and nowhere near 5 they claimed. Ambient is quite warm so a heat pump can be fairly efficient especially at heating but since water needs to be heated to 63C from a 30C or so ambient the delta is still fairly significant. It is fairly hard to justify a heat pump as an investment even in best case where ambient is usually warm as at his location.
That's a great video, I have a 11.47kwh Solar system , I'm also getting a 16kw Sungrow battery soon. I'm thinking of getting one as well, for my house so everything can run on green energy. I like to know after 1 year of usage, would you still recommend. Thank you so much.
I'd think that the hot water heat pump's cold exhaust cold also be used for cooling the house in the summer? Of course there would be some annoying practical considerations, but theoretically that could make energy use even more efficient right? Is this done with any systems, or if not what are the main reasons why?
I don’t understand why you don’t just drive an immersion heater from the solar. Simple, minimal maintenance & efficient. I do this from my solar in the UK. It’s worked trouble free for 8 years now. Am I missing something?
Upgrading to a zero-emmission system around here (Austria, not Australia) also has a few possible government bonuses attached. But here, it's a monetary bonus, you can still put in whatever device you pick, but the refund is maxing out at some point. Is it really that they mandate a specific model or just that most people pick the bottom of the barrel then?
Good breakdown. Of course if you don’t have solar then you’d want to look at cost per kWh from the energy supplier. It maybe cheaper to use 9kwh/day of gas vs 3kwh/day of electricity.
A Thermocline is a _sharp_ temperature difference in water layers. Pretty sure you don't have the volume or horizontal currents to cause that. Even if you didn't have a bunch of turbulence whenever water was cycled in and out.
Too hot of water, yes, on my boat, we use waste heat form engines to heat the water. However that temp goes to about 78C, so it keeps it pretty hot! With only 11 gallons of hot water, being that hot, it limits usage pretty good and allows much longer use of the water before the need to run the generator to use the electric side. The hot water will remain hot for days. Funny seeing a "split" system, as our heat pump systems in the US are all in one units with the heat pump unit sitting on top of the tank.
9:58 "you don't want it too low because then you're using too much hot water to get the temperature that you want" Huh? The amount of water taken from the tank remains the same, the only difference is you mix in more cold water at that point (the standard thermostatic mixing valve) instead of at the tap. For highest efficiency set the temperature as low as possible while still able to get the temperature that you want and without any in-house thermostatic mixing valves/taps start to oscillate.
My only question, why use outdoor air for the heat? One of the benefits of a heat pump hot water heater in a hot climate is that you can get free cooling in your house!
Why didn’t you install an air handling unit inside your house to capture the refrigerant charge of state by recording heat from inside house to cool inside and put the heat into the water tank?
Hi, it's not my first time I put a thumbs up on a great video. But this is the first time I turn 999 thumbs up into a 1k Just sharing the little glimpse of joy!
With a fridge your dumping the heat into the house, air conditioner would be worthwhile although if its reverse cycle during winter you would cool your water.
You can, just place the heat pump next to your devices producing excess heat. They're people using a hot water heat pump to cool a wine cellar in their basement or using excess heat of a combustion based central heating/barn/server farm/household appliances. Of course if you care about the temperature in the room it's advisable to have some control over the airflow. You probably wouldn't want to do this in a heated room like a kitchen in a moderate or cold climate though...
Dave loved your blog, maybe you could comment on my experiance, I just had a Chinesium $2500 heat pump installed for $99 in Kincumber I have 3.3kw solar no battery, SO I programmed[installer did not set] to operate 9am to 3pm which, so far, has used the summer solar. My concern is the winter, the unit is set to just 65°C, not much headroom. The unit does have 1.7kw full freight heater which is selective to off. Bottom line, using solar [I see on last bill I have used some of the 222kwh feed in, there is only a change of $5 on the total bill for January. My old heater was 10 yo, a new heater for $99 is a good deal. IF it dies and no warranty I guess an off peak original will go back in. The subbies were doin 4 a day, my job was acceptable but sketchy, the electrical would not pass regs IMO but OK, the expansion valve drain will discharge on your feet, not legal but ok as they would say "existing" PS they reused my expansion valve insulation kit, just 600mm foam on the discharge, our villa is 34 years old, no pipe insulation, BUT lots of fibre in the roof, the 3/4" line is too big, holds lots of water to go cold, takes 30 seconds for hot water to reach taps. I intend to rerun the hotwater lines in 1/2" PEX, with a return loop to the tank as it takes 30 seconds for the hot water to reach the taps what do you think
You showed you outdoor AC units at the beginning. Don't they literally do the same thing as the heat-pump? So why is there no standarized mix-and-match system where one can just plug in any outdoor unit to any consumption device (water heater for warming, indoor AC unit for cooling)? And since heat echangers are quite efficient: why do we still connect the heat pumps with their respective devices with refrigerants? Wouldn't it be easier and safer to use something like glycol or even plain water?
What is the average price per kWh in Australia these days? Are you affected by all of sky high energy prices in Europe or is it still normal? In Norway we used to pay less than 5 cents per kWh for the last 20 years but now the prices are sky rocking. .30 Euro today and rising, estimated to reach 2 Euro per kWh maximum during december and january...
Another way you can Add Efficiency Is Burying A Coil Of The Cold Water Pipe 10 feet underground And That Would HEAT The incoming cold water up 20 to 30 points
That's weird. When my Reclaim was installed they used the GPO for the controller but insisted on hard-wiring the heat pump itself. I wonder if its a NSW/QLD thing
Commenting half-way through: Just sadface that it doesn't co-exist with the air conditioner pump; with a clever valve arrangement it could use solar to pull heat from the house to the water and only dump to atmo if the tank is full. Edit: So it occurs to me it wouldn't be difficult to duct the air-con hot air output to the heat pump input air (other than being ugly as sin). Seems crazy to dump that useful heat to atmo if you're just going to try to suck heat back out.
Why not direct solar collector for water? Additionally you would have an Inverter to warm up the water at night, but a big enough reservoir should be fine. Because your panels are going to have 25% efficiency tops, through a DC / DC you are looking at 23%. With a water solar collector you are looking at almost 100% efficiency for the same energy coming from the sun. Should be cheaper also and I wouldn´t think freezing is a problem in the land down under. In case you mentioned this, I´m still watching.
The thing is, with a cop of 4, you get the same efficiency as a direct solar collector system, but he already has the solar PV, and energy isn't wasted when the water is at temperature. Further there is the fact that this gets the water hotter than a direct collector system tends to. Had one of those before, and they can struggle. You can also boost from the grid when required and do so with the higher efficiency. Finally if you live in an apartment, this can be installed, whereas you can't do that with a direct capture system.
Makes no sense to waste valuable roof space with a solar hot water collector that ONLY does hot water. Using the space for solar panels can supply the EV, the house, the hot water, and everything else.
@@varno yes but usually you need to get the water up to 50C normally, in winter where the temperatures outside are around freezing (depending where you live) getting a cop of 4 is difficult with such a delta, but on a sunny day you can store enough hot water for the day. Even better inverter air-conditioning struggles in winter just to bring the output air around 30C and these heat pumps are essentially the same type of system. It makes sense to have a heat pump as an alternative as it's not going to be sunny every day or might need more water one day. In the end you could also use the system to warm your house so you get even more for your money, but generally I'm more in favor of diversifying your sources.
@@TrickyNekro I think you have been using older systems with worse refrigerants. This uses supercritical co2, which is ideal for these higher working temperatures, and is also well able to work down to colder temps too. Further this is an air-water heat pump system, so there is more efficiency in the condenser unit too.
Wait heat pumps work better when ambient temps are higher since they can warm the refrigerant easier. That's why until more recently heat pumps that aren't geothermal haven't been considered feasible in cold climates. Thinking through the thermal dynamics maybe the higher energy transfer into the refrigerant makes the pump design less efficient. Might have to whip out the termo books and see what's up.
Either Dave just got this completely backwards, or I'm taking crazy pills. Even the graph in his video at 33ish minutes shows that the COP rises with ambient temperature ruclips.net/video/DO9uccP49_g/видео.html Heat pumps somehow becoming more efficient when the temperature difference is larger seems evtremely unlikely and I'd need to see a detailed mechanism to believe that this would be the case. For additional evidence, each source I looked up on the internet also said that heat pumps get better with higher ambient temperatures (assuming you're using them for heating, not cooling, where of course the opposite is true).
Ambient air... my daily consumption on my reclaim has gone from 3kw/day start of October down to 2.2-2.5kw/day currently. It does jump about a "lot" with ambient air going from 15deg to 25deg. 2 showers a day & some washing up.
Best thing is that even on a cloudy day with a 4.5kw solar system, its 100% free energy at its 1kw/hr consumption!
From 3 kWh/day down to 2.2 - 2.5 kWh/day, supplying you free domestic hot water even on a cloudy day from a nominal 4.5 kW solar PV system is very nice. With a power draw of 1 kW it means the heat pump needs between 2 to 3 hours of operation in your particular use case and the solar system seems well matched to your needs.
@@sietuuba yes, on most days its enough to cover the hot water & do some other low current draw activities. However that may change in winter - i'll be adding more solar soon :)
Wouldn't a solar water heater be better and cheaper as no electricity is used at all? Maybe they're not that common there.
@@GeomancerHT They are quite common depending on where you are, new builds some councils mandate a solar water install. You are 100% correct - they're the most efficient way to heat water - however, they're not the most efficient use of roof space - thats the thing. If you have loads of roof space - its the best option. If you have limited roof - you're better doing solar, so that the other 1/2 the day its producing for you.
@@nateb3105 thank you!
As a canadian its very interesting to see all your utilities placed on the outside of the house. Your breaker, water tank and drain pipes being exposed give me the hee·bie-jee·bies. Must be nice to stay above freezing year long :)
HA ya in Montana everything is in the basement but in Arizona everything is outside I do miss the basement but in Arizona i get what I call perma hot dirt the water in summer is never below 90F
I live in Scandinavia. nothing is outside. if it was it would break in the winter.
same here, Czech Republic 😁
Came here for same comment - UK is all indoors
In Canada the cold supply line would freeze and you'd have to burn way more gas tokeep the water hot at -20C ambient. The supply line comes in the house at well over a meter deep and the main water pipes (supply, sanitation and storm) run at a number of meters deep in the street, all to avoid freezing up.
Another fun fact... the bigger the tank, the more efficient its heat retention (volume vs surface area). This also allows you to program the controller to not run the heat pump during certain hours (e.g. avoid high time-of-use electricity rates), and not have to worry too much about running out of hot water. I have my heat pump water heater programmed to not run between 4pm-9pm and its never been a problem for us.
Our heat pump water heater uses around 4kWh/day. That's about the minimum. But I also have a hot water recirculator and the pipes are pretty long. When I run the recirculator on a timer in the morning it adds 2kWh/day for 6 total. But its better doing that than wasting water witing for the hot to get to the shower.
Your 2.83kWh/day is pretty awesome. That is a number to be proud of! I mean, compare it to the solar output. Our upgraded 5kW solar system produces 30kWh/day+ during the summer and around 16kWh/day in the winter. And the water heater is using just a tiny bit of that... I'm a happy camper!
-Matt
Totally on point; big enough heaters are indeed useful for split tariffs. I've got a Stiebel Eltron SH120S in my flat, retrofitted with a ESP8266 based controller that allows me to turn it on and off from my home automation system. It works from 4 till 7 (end of the night trough), then 13 till 16 (afternoon trough). Six hours a day, though the night trough starts at 22. The reason why I don't want to turn it on in the evening is exactly what you mentioned: stand-by losses. Minimizing the time it's hot means minimizing the energy losses, though that tank is already real damn good in this regard (around 1kWh per day at 60 deg C).
Oh, and @EEVBlog finally got some insulation on these pipes now! I wonder why it wasn't there with the gas heater.
@@KeritechElectronics heh yah, I noticed the lack of insulation too but forgot to comment on it. The copper pipe is a big radiating surface. I forget what the wattage per foot is (copper pipe, 125F water, 70F air), but it is not insignificant. Multiply by 24 hours a day, 7 days a week... definitely not insignificant.
An outdoor water heater is such an unusual concept to me! We have to have all our stuff indoors because of freezing weather.
These work in alpine regions
You can set the mixing valve lower without fear of using more hot water, it will just mix in more cold at the valve as opposed to your tap. The only difference is the maximum temperature of "full hot" at your tap will be lower (which is what you seem to want).
As long as the water temperature (and usage pattern) is ower legionella bacteria survival criteria. According to wikipedia "At 50 °C (122 °F) - 90% die in 80-124 minutes" en.wikipedia.org/wiki/Legionella#Heat
@@AnatoFIN the hot-cold mixing happens after the tank. The tank is heated to 60+ degrees at least once a week. So no legionella risk by changing the tempering valve setting.
@@-vermin- Legionella can grow in the pipes. I would prefer if temperature was high enough to inhibit Legionelle growth from the tank trough the tempering vale to the tap.
I admit I'm no expert on this, but at least in Finland, ministry of environment regulation (1047/2017) specifies that hot water must be over 55°C everywhere in the hot water system to inhibit Legionella bacteria.
I set my heat pump tank (yes, my tank got its own heat pump as part of it) to 54 degrees celsius, with no anti legionella cycles because there's no need to go fast kill when the tank ramps up to slow kill twice a day and stays there for hours each time. And I discard the cold part from the pipe. I have it in a roofed outdoors area, kind of like a porch. I want to move it to the back garden washroom though, to reduce pipe length and act as a forced air intake into that unheated space. Valencian village, so even though air freezes in winter it's only in the night and usually less than two weeks, so no time for pipes that are being used to freeze, especially with insulation on them.
I installed a heat pump water heater and I'm thrilled by it.
I keep it on heat pump only mode and it does great. The water heater that came with the house was oil fired, and it wasted a lot of oil. Same with a gas unit, heat rises up through the flu pipe while it's off and convection cools the tank.
As a retired electrical/electronic engineer, I enjoy watching your knowledgeable and pragmatic engineering approach to problem solving. Well done!
400 Liters! The biggest residential tank I've seen in the US is 65 Gallons (240L), and that's "big". My husband would love to have that setup 🔥
In the US, the whole unit is typically installed inside so it does double duty cooling and dehumidifying the air, along with heating the water. That makes a lot of sense in the warmer southern climates. I was surprised to see yours mounted outside. This was really interesting. Thanks for sharing.
Interesting! How does that work in winter? Presuming the outside temperature does sometimes go below a comfortable room temperature, you’d be heating and cooling at the same time when the hot water heater is running. Or is there some kind of valve to send the cooled air outside in that case?
RickMakes I don't know if that is a regulation down under, but I have often wondered that myself. It makes no sense not to be trying to maximise the surroundings. How can rain pelting down on a hot water system be help its efficiency?
@@DodgyBrothersEngineering they drink so much Fosters, they've ceased to care.
@@DodgyBrothersEngineering usually there’s still roof overhanging the unit, and like Dave pointed out, it’s so well insulated it feels room temperature on the outside anyway
@@MattyEngland does Fosters still exist? I haven't heard that name in ages. I seldom drink at the pub, but I can't remember the last time I saw it.
I like the design of that. Here in the US they are a combined unit (at least the common residential units) with the compressor assembly sitting on top of the tank. I suspect the remote unit like that could be a little more efficient since you probably have a good bit more area for heat exchange. As it is, I'm using about 1/3-1/4 less power over our old resistive heater. (Varies by the temp in my garage). Still completely happy with the purchase, after the local rebate we got the unit will have paid for itself in under 2 years!
Given our current electricity rates, we're paying anywhere from $.30 to $.60 USD a day for hot water. That would have been between $1-2 usd with the resistive heater. Last week we averaged 4.2kWh /day power usage on the unit, and that's with 38-45 deg F air supply temps. This past summer when it was over 90f in the garage we were down near 3 kWh /day.
Same here, I love my hybrid... I keep it on heat pump only.
I had an old (1995!) oil fired cylinder and it was a huge waste of money and oil. It ran more often than my hybrid unit which pulls 450W. I left it in the house for a year after I bought the home, and then I kicked myself when I saw how fast it went through 125g of oil!
Let’s hear how cold your garage is in the winter time with that thing suckling all the heat out of your garage.
Tanks with the heat pump setup sitting on top are, or at least were, available in Australia.
Sanden makes a split unit available in the US. It's pricey though.
@@USA-GreedyMenOfNoIntegrity Quite cold, but who cares, its the garage. Makes it a bit nicer to work out there in the summertime though. The garage is to the side of the house as opposed to under or above, and the walls are well insulated between there and the living spaces. I'm also planning on ducting the intake to the attic which is directly above the unit, so it will have access to much warmer air temps almost year round.
I guess if you are always refrigerating your home and it never really freezes then it makes sense to have your hot water outside. Where I live, 60% of the year I'm heating my house, don't have AC, and we definitely get well below freezing. If a little heat gets out of the hot water tank, it just heats the house so it isn't wasted.
I am impressed by your triceps
Consider adding some insulation to the overpressure valve since it is hot losing some of your stored heat, even add more insulation to the exit hot water pipe.
OK, I'm about to start watching the video as a month ago I had installed a Reclaim heat pump and Earthworker 315litre storage. Two weeks ago we got the 6kW solar array done and set the Reclaim to mode 4 (only on between 10am and 4pm). It's been using 1kW between 10am and 11:30am-midday and so far I'm extremely happy with it. Looking forward to what you discover with your own system!
Great series of videos. Must watch for anyone considering to switch.
You can't ask for more than this: an example of a system installed with costs compared over a year.
I love your engineering breakdowns. I have a Rheem 50 US gallon heat pump water heater set to 120F or 49C and your KWh usage numbers almost exactly match my KWh daily usage. There are no mixer valve requirements here. It’s located in my garage, so it reclaims the heat from my and my wife’s cars. I am jealous that you have a stainless steel tank. Here it’s all about planned obsolescence, meaning a glass lined steel tank, UG…
I found similar performance with my 415L heat pump in Sydney. After 6 months of investigation, I figured out the real issue, built my own controller and it now uses around 1kW/h per day. You are getting too much reheating of hot water due to your oversized tank, which is lowering the COP.
yep, thats what i thought, he is wasting too much hot water every day, as he is not using it, and the tank is oversized for his house really, and its costing him to reheat it every day.
But the prices in nothing, as its not really noticeable to him, as he is getting energy from his solar.
"reheating of hot water"? that's not how thermal dynamics works...
With low water usage, the top half of the tank will be warm and the bottom cold. When the heat pump runs it will heat up the colder water at maximum COP, while the warmer water will be at much lower COP. You get surprising good temperature separation of hot and cold water in a tank.
The thermal interaction is quite complex and too long to discuss in a comment. If you want the full details you can read about my solution on the news site HACKADAY, search for HEAT PUMP and find the article written by Bryan Cockfield.
@@SqueakySnow the video in the article is no longer available
Dude; great work as always, thanks :) One point, and I know that you already know better: I would like to clarify for the benefit of any who are concerned, but not necessarily so conversant with energy, and especially within the wider political/environmental context.... Your comparisons between the actual water heating apparatus is of course absolutely correct, BECAUSE you are producing your own SOLAR derived electricity. For anyone using electrical power generated from a mix of primary energy sources, then to get a fair account of the overall energy consumed, then appropriate adjustments would needed to be included, for example, for coal fired generation:- 100 GJ (coal) in for 35 GJ (Electricity) out; along with the corresponding overall reduction in system efficiency and increase in overall environmental load (ignoring overall "embodied" energy considerations).
CO2 refrigerant mate, that's cool! (or Hot I mean!)
Really says something about the climate when you have the hot water tank OUTSIDE, jeez you aussies!
I think your PTC element calculation is spot on, that's more or less what I measure on our 200l hot water tank in the basement split between two apartments, so 3 adults and one child. (numbers from Norway for those playing along at home)
Recently I have been looking at a hot water tank with a heat-pump installed on top from Vaillant, it uses an R290 refrigerant I think, however for the life of me I just cannot get hold of any useful data for my region. Average yearly temp here is 7 degrees Celsius, so not particularly cold, but quite an expensive investment without knowing potential savings.
You are certainly building an excellent system in your home.
Fair play to you.
These videos are fascinating, seeing how your slowly improving the energy efficiency of your home.
When it get to winter in 7-8 months time where you are, you should do an update in how your heat pump is working in your coldest conditions where you are.
Have you say, your energy prices are so low, you do not appreciate just how low your energy prices are where you live, being in sydney where alot of your energy prices will be subsidised by your gov to attract investment there. All major cities have this advantage to live there, to draw investment and workers there.
If you can, you should do a series of videos on all your energy resources in your home, and show people how energy efficient your home is now, and break it down into segments.
Did you get your battery backup for your solar panels yet?
I’m a sparkie in nsw. The pcb on the heat pumps fail all the time, and generally the warranty on them is only 2-3 yrs on the board but 10yrs on the tank.
I’ve ended up replacing them back to element heaters as the price doesn’t suit most people for repair/replacement boards.
Hope you have better luck but you would have been better with an element heater and a day time timer
My townhouse has 6 split system heat pumps for heating/air conditioning installed about 15 years ago, 4 have now died.
On this exact brand and model?
Measure that temperature again to see if it was not a Fluke! Ha. Arthur looks nice.
I got a tempering valve on my hot water system with an electric storage heater... Mighty useful! They're not standard here in Poland, but I highly recommend them.
Apart from the high-ish COP 5 claimed by Reclaim, the real deal data loooks nice and I like that you state the limitations of your methodology, and how they can affect the tests.
Tank stratification very nicely explained!
Thank you for the detailed breakdown! We're in a similar boat as the one you were in; we've only the tankless as out last gas appliance.
In the whole last year, we've used 13,861 kWh of electric, and ~3600 kWh equ. of gas. The kicker is that with solar/batteries, the electricity cost $.0012/kWh, totaling $16.50, and the gas was $289 or $0.08/kWh.
It's amazing to me how much more expensive gas must be in Australia. I figure our daily kWh, was 9.8 where yours with gas is 12.8. So perhaps our usage with this setup could get down to ~2.14 kWh/day (I'd optimistically figured it would be below 2).
So if our electricity rate stays roughly the same, we'd pay less than a single dollar for a little under 800 kWh in water heating. That sure would beat the nearly $300 a year we're paying now! Lol
Depending on how good the heat pump is, if it is one with backup thermal elements you should try turning those off (its usually a configuration option) and see how well the heat pump does just by itself. Given where you live, it should work quite well.
I wound up getting a SanCO2 heat pump water heater. No backup heating element. Separate outside unit and in-basement 80 gallon steel tank. Its been wonderful. This particular model is designed to heat the water up above the biological survival temperature, e.g. 155F and higher, and has a mixing valve on the output to bring it down to something reasonable for the house hot water pipes (e.g. 125F). Hence also why the tank is steel. And since there is no heating element inside the tank, it is literally just a steel tank with some valves and insulation and there isn't a whole lot that can wear out. It should last a very, very long time.
So far the system has been wonderful. We have never run out of hot water. In fact, even if we use most of the tank the water never actually gets cold because the heat pump's water heating loop emits directly into the top of the tank. Takes water from the bottom and runs it through to the top.
Consumption is around 4kWh/day. If I run the hot water recirculator on a timer 15 minutes a day, consumption increases to around 6kWh/day.
It always amazes me when I see water products, like washing machines, and water heaters outdoors. I live in Colorado, and it will be -9 F on Thursday, for a high. Everything that can freeze is indoors.
We're thinking of moving away from our gas hot water system and stove as well. Unfortunately, since our (newer than yours) Rheem had the bottom rust out of the tank we got a far more efficient "on demand" system as a replacement, however that was before our solar panels were installed so it's still relatively new.
Downside will be that without a battery we can never have hot water production during a blackout (the only benefit of the old system) or use the stove.
Nice! What a coincidence, I have a Reclaim system in my garage that I’m just about to have installed! Looking forward to using my solar power directly for hot water instead of exporting it for 6c and then buying it back for 19c/kWh into my old rusting conventional system!
Your figures are very similar to mine after conversion. Had an on demand gas at the old house, an old off peak tank at the current house and converted this to a Rheem 320L heat pump unit. We are on a 5 kW (rated ) solar system. South Aus, near Port Wakefield. Instant reduction in our power bill. I recommend this to everyone. Our unit cost $4000 installed.
I'm keeping my old tank. Going to set it up as a standby solar cell only heater for outdoor hotwater for washing the doggies.
I understand that in Australia there isn't a lot of need for heating, but here in Finland heat pumps of various kinds are used extensively for heating buildings and water also. The most effective ones use drill wells where heat is transferred from the soil by a circulating fluid, such as ethanol, but the initial cost is high, about $10,000-$20,000 for a single family house. A cheap alternative is a heat pump which extracts heat from outdoor air, and those are as cheap as $2,000, including installation. Their disadvantage is that efficiency falls when temperature gets cold, and they completely stop producing heat at -30..-25 Celsius.
Newest air to air heatpumps can work down to -35C .. There might have been one -40C too..
I almost had a headache, until you said you got Mitsubishi!!!!
Looks good on the install of Arthur, and they did a pretty good job on insulating it. Looks pretty good, and only criticism is the airflow around that evaporator, should be a little further out, along with the AC units, to get good airflow around them, which does make a big difference to off coil pressures in the system. The R744 is a good refrigerant, though the pressures at the top end of the system are scary high, 40 bar plus, but at least a failure is just going to be noisy, and pop the TP valve for a few minutes as it vents.
Should have had a measure of your hot water use, water meters are pretty cheap (funny though the last one I bought the brass was cheaper than the plastic, probably because the plastic ones are sold at a massive mark up, as they do not get stolen) and work well as baseline for water use (more data better, allowing you to see split of home water use for hot water, cold water and garden, which likely is the biggest use) and power use. But yes you will be saving money off the bat, essentially whatever the gas bill is, of which I would say most went to keeping that pilot flame lit all the time, and the gas usage would probably be overall less than the pilot flame use.
As to pipe temperature drop, it is lowest at full flow, do another test with low flow, like you would use to wash your hands, and compare again with the radiated heat in the roof, easily going to be 10C at low flow, where the water has longer to lose heat in the pipe.
I just found a shower head flow meter and temp meter on ebay for $20. Didn't even think to look for that. I didn't want to screw up the new copper pipe work just to install a proper flow meter.
EDIT: Nope, the ebay one is just a temp meter, uses the water flow to power it.
@@EEVblog Just a thought, I used water meters at a previous job so I could monitor water use on the ion exchange resin, and also budget the cost per batch.
I'm not sure I'm that keen to get exact data. I'd want it logged as well, and then I'd also need a automated temp loggers as well. I'd be doing Reclaim's R&D for them at that point! They should just publish some characteristic curves.
@@EEVblog They probably have not got the data other than under lab conditions, no real world data really. Easy enough to add in the data logger and water use monitoring, as most water meters have a built in magnetic wheel that generates a one pulse per 10l signal that you detect outside the case. Simple data logger integrated into the solar system data would not be much, just 4 channels to record ambient temp, inlet water, outlet water and pulse count.
@@EEVblog Incidentally, as a experiment go out tonight with your thermal camera, just before bed time, and long after showers are done, and look at the tank and heat pump, and look for the hot spots. Those are all heat leaks, that all are the majority of loss from the system. Add more insulation to cover those losses, which are all the exposed copper pipes on the hot loop and the overpressure valve, and you will see a few minutes less runtime on the system, as the majority of the static thermal loss is via the connections and pipes conducting heat away. Cheap upgrade that makes a big difference, especially on electric units, where this is around half the energy loss on the modern ones, the rest coming through the cavity for the electrical connection, and a small amount from the insulation around the tank.
Incidentally make a calendar note to change the sacrificial anode on the unit in a year, order 2 spares now (while still available), and you can then extrapolate anode wear from the inspection, so you can roughly estimate lifetime. Your anode will wear first, then the tank will corrode through, though the heat exchanger is likely the first part to fail. Anode typically lasts 2 years or so, depending on the water softness, and when it is gone your tank is the sacrificial anode instead. By me a new electric heater is only $400, so cheap to replace with the identical one.
I would be very surprised if it's actually more efficient in colder weather. Basic thermodynamics says the highest COP should be at the highest ambient air temperature.
According to the designer (I contacted him), yes it performs better in colder climates. With C02, the colder in ground water temp to higher the COP. But also the higher the ambient temp the higher the COP.
@@EEVblog to prove this to us you should make a video about the phase changes of multiple refrigerants and their resulting maximum efficiency temperature deltas! :P
@@shittubes What the designer was saying is that it performs better with lower cold-water temperature. But it also performs better with higher ambient air temperature. Therefore, Dave is getter poor performance, as he is only using a small amount of hot water tank capacity. So the system has to reheat a lot of warm water already in the tank at a greatly reduced COP. My simmilar system only uses 1kW/h per day.
@@SqueakySnow i agree 100%, given the placement of the valve that goes from the tank to the heatpump, if he doesn't use most of his tank's capacity that water will be way too warm for getting to any high COP. where i live there are also other more elaborate systems with multiple valves at different heights to optimize this slightly, but i guess it's just not needed with this abundance of solar energy in australia
@@EEVblog that makes sense that the COP would be higher with a colder water temperature. But I think you'll still use more energy overall, heating cold water than warm water.
I'm wondering if you were underestimating the amount of hot water you were consuming from the old gas system.
The one time my gas system went out it took like under an hour to heat the whole tank from ambient to hot.
So you wouldn't run out of hot water unless you all had long hot showers back to back, as it is heating the water at a reasonable rate compared to your usage.
As opposed to your new system which is entirely stored hot water at the time that you are using it.
I’ve got solar panels and an immersion heater for hot water. There’s a controller which uses PWM to vary the power going into the heater to match what would have been exported. This is great because it can use anything from 0 to 3kW to exactly use the right amount. There’s a late evening boost in case the sun didn’t shine enough.
Wonder if the extra efficiency of a heat pump would be worth it here… also is it possible to vary the power consumed to match that being exported, like the immersion heater? Most heat pumps have inverter control now but can that be coupled to the export power?
As a canadian, it blows my mind that you would install this outside!
Getting rid of heat from the house is a bigger issue in Aus that retaining it.
I need one of those temper valves! I'm up in PNG and have the roof mounted solar water heater. Every few months I go up and pressure wash the dirt and junk off the panel and the next week the water is absolutely scalding!
The diagram @33:15 is showing lower COP at lower temperatures for both refrigants, so the efficiency in colder tasmania should be worse, not better. Perhaps they measured efficiency through a heat wave..
Oh that's interesting it's two pieces! Over here in the US we just started pushing for more efficient water heaters although they were fairly well efficient already. as nobody likes their hot water getting cold that they paid for. The units now have everything in the top foot and a half section of the water heater. They also include electric back up or/and boost. And there's a temperature range adjustment because well bathing is one temperature and sanitization and commercial kitchens or another so you have to find a setting for your liking and safety. within that range you also have to keep in mind more energy usage for higher temperatures.
We have what is called a mixing valve same thing as you're calling a temper valve. It's not used very commonly as it's more normally a matter of setting the temperature on the water heater. However in places where you would need extra extra hot water and not so hot water say sharing a industrial kitchen with a bathroom or similar. It can be also used to prevent pipe freezing by circulating some of your hot water back into the cold water lines on outside wall sections of additions.
To measure cop. Turn off heater. Remove tempsensor. Flush out all old hot water. Start heatpump and log electrical energy until "cold out" reaches 60°C.
Well done, great explanation of real world asap performance, get a battery and use off-peak electricity too
Will it last 40 years like the gas system though. That will be the real test. 🤔 How long will it take to pay for itself vs gas?
Technology Connections should be interested in this video since it’s Heat Pump.
Am thinking a tank mounted outside here in Scotland would be a large block of ice in the winter.....LOL!
Yes! It's so out of the norm for me to see water piping and appliances outside!... But even in the US (where I am) it is also the norm in warm climates... But it was already -12c the other day where I live, and winter is just getting started, so I can only dream about that!
It's going down to -34° tomorrow night where I live. It's so weird to me to install a hot water tank outdoors haha
He never fails to show his triceps in the thumbnail...😄
I use direct DC from PV to electric hot water heater elements. I am working on a project to divert some of the input dc from PV before it gets to the controller ( on separate battery system). Then any excess not needed to keep the batteries full will go instead to heat the water - no conversion losses by controller or inverter.
I like the idea of having it outdoors. That mitigates a good portion of the risk people here in the US face by having it in their basement or garage.
What risk? Leakage?
@@AttilaTheHun333333 Critical failure of the pressure vessel. My grandmother had one go through her first floor. Didn't make it through the roof, but damaged the kitchen that was sitting above it.
Realy liked it, wondering why this is not a standard for residential house, or apartments. It could even reduce cost of heat pumps if they are produced in huge numbers.
You could possibly fit a recycling pipework set up to the tank to reduce the cold spot effect at the bottom of the tank ( brings to mind Appollo 13 stirring the tanks). Also the effect of ground cold on the mains water feed will affect how much power you use to warm the tank.
My gas bill tells me how many TH I have used over the month. I read through the utilities website and found (TH) is Therm. Therm is apparently 100 cubic feet of natural gas. 1 Therm is also 100,000 BTU or 105,480,400 joules. I was digging into all this to try and figure out some of the math like you did as a possible comparison of different water heating choices. I then remembered this exercise is almost pointless because I not only have a gas water heater, I also have a gas furnace and a gas stove.
So what you’re saying is that you’ll be installing a heat pump stove?
This is a useful video because I am thinking about swapping out my solar hot water system for a heat pump. The solar hot water is great on sunny days when the only energy comes from the few watts consumed by the circulation pump.
However on rainy days like today, it can chew power with a 2.3kw booster. I have a sensor in line with the booster thermostat about 30cm from the top of the tank. To take that from 45 to 53-degrees C took 4.75kWh (then the sun came out about gave me another 5-degrees for “free”). The tank has a thermowell about 30cm from the bottom for the solar pump sensor. When the tank was reading 53 at the top, the bottom was reading 51C.
On a good sunny day the top of the tank can easily reach 73C. The water direct from the solar collector can be 100C+.
However, just a few rainy days would put the heat pump in front.
Hi Mate,
I think you'll find that if you used the full 400lt every day, your relative COP figures will be better still, much closer if not better than 5. This is because it takes about the same kWh input to heat from 20 to 45 degrees, as it does to heat the remaining 15 degrees to 60. This is due to the greater temp differential when heating at the lower temps, meaning you get better relative COP figures thrifty the first half of the heating cycle. This has an impact when factoring the volume.
If you try it for a week, empty or the hot water prior to the daily heating cycle, so you're heating the full tank, not just 170lt, and redo your measurements and COP calculations, you'll find better relative efficiently and better overall COP when heating a larger volume of water.
Great video, very interesting and informative. I would like to do the same, but being in a rental I can't. Out of interest I decided to calculate our annual gas consumption in kwh to see where we stood. We have gas hot water storage, instant gas hot water in the kitchen and gas hydronic heating, our total gas consumption for the 12 months ending October '22 was 21095kwh, 58kwh/day. OUCH.
WHAT! 58kWh/day!
Got a 300 liter tank with a 500W heatpump on top. I have an esp8266 checking the shelly3EM power meter and if it sees more than 400W going from solar to net it switches the heatpump on. Off when solar doesent deliver of wifey is cooking or washing. Works quite well in summer and not at all in winter.
On other countries, such as Thailand where I live part time, we use tank less water heaters.
One in each bathroom.
They cost about $100 each.
Our oldest one is a twenty year old Electrolux. Still works great.
Truth be told, we only use them on cool days and there arent many of those.
In Europe we have solar systems too but for hot water we use vacuumed tubes with heat pipes in arrays of 10 to 30 pieces. Maybe if you account the solar panels efficiency per square meter the vacuumed tubes are more efficient. Plus in a no frost area you could use direct heating vacuumed tubes that heat the water directly in the tubes wich raises in an upper tank using no electric energy. Useful in no energy available environments.
I have the same tubes here in Perth WA. Its backed by an LPG fired on demand heater that only kicks in to boost the water temperature to 65C (if the inlet is below this) when a hot tap is turned on. Being LPG I run it on 8kg BBQ gas bottles. The LPG also feeds the gas hob. The warmest 6 months of the year I run on one gas bottle, the cooler 6 months I use one a month. At $30AU per re-fill my hot water and hob cooking is costing me $210 a year.
Dave, a medium sized single solar water heating pannel on the roof will give you more energy than half of the photovoltaics you've installed. In energy sources poor continental Europe photovoltaics are considered "they have more money than they know what to do with them". For europeans living in moderate climate zone with full four seasons with snow covered couple of months in the year living a house you can expect to find in their house hot water tank with 2 or 3 heat exchange coils - for solar, wood or gas burner and for a heat pump plus a direct heating element. High efficient solar heat pannels that requires pump for heat transfer fluid can heat your boiler from 5 - 8 degrees Celsius winter tap water temperature to over 30 degrees even in freezing cloudy period with short days and weeks without sun thus cut energy requirements from not free sources in half and in the summer it well produce heat more than needed.
I just bought the Rheem/Solarhart equivalent, keen to see how the first bill comes out!
4:26 Sure there is loss of heat from the exposed pipes. It's just that the boiler is hot enough that the pipe is maintained at the same temperature. If it is a particularly hot day, then the pipes through the roof might not lose too much heat but in winter it will be a different story.
You guys have some crazy good water down in Australia if that's only the second water heater your house has ever had. I don't know of too many places here in the US where water heaters can last that long. My dad wants to replace his gas water heater with a heat pump style as well. His water heater and furnace are in the same closet. He'll be able to use the Water heater to augment the Central Air conditioning in the summer.
Very common here for tanks to last many decades.
Yeah they must have soft water there. Around here without a water softener that water heater would have been full of lime many years back !
Wow! Here (west coast Canada) water is soft but first gas heater lasted 11 years and worried as we are 11 years into the second. (Everyone in area has similar life spans)
@@tegra5971 There is a sacrificial rod in water heaters that needs to be replaced. If not then instead of the rod getting corroded it will start to corrode the tank. Look it up on youtube - sure there are videos explaining that. When those rods start to go bad sometimes it can make the water smell like rotten eggs. Those rods can be kind of hard to get out if the cap on them is all rusted in. I think ask this old house did a video on replacing them.
Outside water heaters are common in southern California, not so much in the Midwest.
Gas in the US is measured in CCF or therms. CCF is hundreds of cubic feet; therms are CCF compensated for actual energy content.
You can get gas water heaters with much higher efficiency. The one in my house in Ohio was rated for ~90% IIRC. It did have some odd things to get that efficiency. The flue shot out sideways and had a blower. The thermostat was weird: it controlled the blower, not the gas. The gas was controlled by a vacuum sensor on the flue. If the blower didn't start or was blocked, the gas wouldn't turn on.
Yanks are weird.
14:15 You could directly compare the consumptions based simply on the bills and the price per unit of energy consumed (assuming the two systems are set at the same temperature). For the comparison to work though, you have to assume equal amount of cold water going in and to determine that you would need a flow meter on the inlet (as pointed out at 29:15).
The bills might be higher than expected with the new system due to increased consumption. It's very easy for the consumer to assume that just because the new system is more economical on energy, then it will be fine to consume a little more hot water - but in practice it might prove hard to judge exactly when "a little more" becomes "a little too much".
I’m a few months in on my ‘cheap’ Chinese heat pump that was $33 on the government scheme, it’s a Midea model and is working great so far.
No Really Great Video. And A Very Very
Thourough Explanation Of It.
Great Dane. Thanks For The Vids.
First I grew up in a house with an 85°c hot water system, yes that's what came out of the taps.
Secondly I just got a free heat pump hot water system at my business property due to a government program.
Thirdly I live in the same city as you.
Tempering valves are awesome! Double your effective hot water buy heating the water in the tank hotter than normal and then mix down to 125 in the US. Be sure to get a spare since they do fail quicker than I thought. From experience. Mine failed closed thankfully but my wife found it not me. :(
The new plumbing standards will make a huge difference as well. The tempering valve effectively "extends" the amount of hot water you have available by mixing cold at the tank outlet so is more efficient. I'd imagine they also installed a cold water expansion valve as well which saves you from having hot water dumped out the valve (wasted energy) when the tank is heating.
The mixing valve does not affect the amount of hot water you effectively have. If you set your water faucet in the shower to keep a temp of say 45c (113f) then it doesn't matter where you mix that water as long as you mix it to the same temp. You can have a 20c and 65c supply to the shower then mix it down to 45c, or you can have a 20c and 65c at the hot water heater that mixes just a little down to 55c, then mix a little more from 20c and 55c at the shower. Either way the cold water is 20c and the hot water in the tank itself is at 65c. No matter what you do the water in the tank has to drop from 65c to 45c and where that drop happens doesn't matter.
For the expansion tank, most places require it by code if you have a supply check valve at the meter, otherwise pressure could rise dangerously in the system and release the pressure release on the hot water heater.
@@2009dudeman There is efficiency loss in the piping, the heat radiates into the walls. By having an already lower temp transiting the piping through the house there is a lot less energy to lose.
Hot water cylinders have always had expansion valves, but on the hot side rather than the cold side. This means that when the tank is heating and pressurising, the relief would come from the hot side, which is already heated water which is a waste of energy. Cold water expansion valves are part of the new standard so you are releasing water from the cold side instead of the hot side, so wasting a lot less energy.
@@ipullstuffapart I'm sure there is measurable loss, but whether that's significant or not depends highly on the specific system. But you generally aren't losing a lot except in the worst case. I have copper pipe, which is pretty much worst case for radiating and conducting heat from the water to the surrounding environment and even I have an almost non-noticeable difference from one side of the house to the other. I would guess maybe 1c difference off the cuff based on measurements taken over the years, but I have never measured one side right after the other, only during refit. If your house is newer and using PVC or pex the heat conduction through the pipe is minimal. The only way I could see it being worse is in our Michigan basements with copper pipe, you have ground temp air surrounding the pipe instead of internal piping with a full basement where air temps are controlled. But you can have foam wrap put on the pipe that reduces this heat loss significantly. When I put foam on my pipe the water in the line stayed hotter a little longer while sitting after using hot water but I felt no difference in water temp at the sink on the far side of the house.
Legionnairea disease being a concern is the reason code prevents hot water side expansion as it's entirely possible to have water in a dangerous range for long periods of time in a hot water side expansion tank.
So weird to see a hot water tank outside! Wouldn’t happen here in the Uk 😊
Only because someone would nick it for the copper....... andas for Aussie electrics Brrrrrrrrrrrrrr
All that uninsulated pipework too!
Haha, agree with both of you. Someone would steal it, and the uninsulated pipes do look weird 🙂
If you don't need 63°C turn it down to 50°C as you know and like your hot water
You want to turn your mixing valve as low as possible because you mix the hot water with cold anyway to shower and whatnot. So better have a already not so hot (and not insulated!) pipe going thru your house (and loose less heat) then mixing it at the destination.
You can also run the whole Tank cooler (if your heatpumnp controller supports that)
Saves you energy in booth ways as the tank looses less and the heatpump will have a better COP
Also you could set this thing up the way that it heats to 63°C only with excess solar power and drops down to 50°C at night (which might also get you through the night without drawing anything from the grid)
Some people are obsessed with bacteria growth like legionella, and when they are doing the regulations they may require such a temperature for any stored hot water to prevent it.
In my system I have only flow heating (no storage tank) and indeed I have set it to 50degC as that is plenty hot enough.
I've watched loads of your videos and I had no idea you had a second channel😂
Interesting to see the temper-valve being external. I'm used to them being built into the output of the tank so you can't bypass them.
Would it be more efficient to run the heat pump at a lower temperature? Running a legionella cycle once a week?
I'd love to have a "temper valve" actually. If I set the boiler to 90°C, it'll happily spew 90°C out of the tap lol. instant burn if you touch that !!
Interesting, our heatpump hot water is all in one, the heatpump itself is sitting on top of the tank, it's pretty sweet, we run ours from 11-4 to make use of the higher air temp as much as the solar
Yes a water flow meter on the cold input line will have been helping a lot with efficiency calculation.
Water flow meter also has a nice side job as a leak detector. I've got a hall-sensor based water meter reader after a broken underground pipe drained about half a year worth of water supply. I'm glad I did. Over the last year or so It has detected two minor leaks before they became a real problem.
Why? For the old system 170 l was taken as more or less how much is used. At least with that number the comparison is done.
@@mauricevandoeselaar There was no flow measurement for the old system and it was at best a guesstimate.
Old system had temperature output set at 51C so a 31C above cold water input and it used 9kWh per day in average including the unknown loss through thermal insulation.
To heat 170 liters by 31C you need just 170 * 31 *1.16 = 6.1kWh so unless 3kWh where lost to ambient trough that tank thermal insulation each 24h then more water was actually used.
@@electrodacus the old tank was only 170 l so it's safe to say that that is the maximum they used. And yes the old system was not that efficient. But the new system also only has to supply the same 6 kwh (its safe to assume they still use the same amount of water) not 12 because this tank is larger.
@@mauricevandoeselaar I'm fairly certain the new tank has better thermal insulation so even if larger losses to ambient should be lower.
The thing is that losses to ambient are unknown thus you can not be sure that 3kWh where loses to ambient on the old tank or they where less and then he used more than 170 liters / 6kWh for water heating.
In any case he uses around 3kWh now so if he has the same consumption and losses to ambient then COP is only 2 in any case less than 3 not around 4 as he concluded and nowhere near 5 they claimed.
Ambient is quite warm so a heat pump can be fairly efficient especially at heating but since water needs to be heated to 63C from a 30C or so ambient the delta is still fairly significant.
It is fairly hard to justify a heat pump as an investment even in best case where ambient is usually warm as at his location.
That's a great video, I have a 11.47kwh Solar system , I'm also getting a 16kw Sungrow battery soon. I'm thinking of getting one as well, for my house so everything can run on green energy. I like to know after 1 year of usage, would you still recommend. Thank you so much.
so glad it doesnt snow where i live
I see that tricep popping big man
I'd think that the hot water heat pump's cold exhaust cold also be used for cooling the house in the summer?
Of course there would be some annoying practical considerations, but theoretically that could make energy use even more efficient right? Is this done with any systems, or if not what are the main reasons why?
I don’t understand why you don’t just drive an immersion heater from the solar. Simple, minimal maintenance & efficient. I do this from my solar in the UK. It’s worked trouble free for 8 years now. Am I missing something?
tempering valves are always on the outside .... Make sure the tank water temperature is at or above 55 degC .
Upgrading to a zero-emmission system around here (Austria, not Australia) also has a few possible government bonuses attached. But here, it's a monetary bonus, you can still put in whatever device you pick, but the refund is maxing out at some point. Is it really that they mandate a specific model or just that most people pick the bottom of the barrel then?
420l is just enormous. The largest boiler I've ever seen was around 200l for a typical family with kids taking a bath every day.
Good breakdown. Of course if you don’t have solar then you’d want to look at cost per kWh from the energy supplier.
It maybe cheaper to use 9kwh/day of gas vs 3kwh/day of electricity.
The latest war took care of that problem. Gas price increased by more than 120% - suddenly these heaters become feasible.
A Thermocline is a _sharp_ temperature difference in water layers. Pretty sure you don't have the volume or horizontal currents to cause that. Even if you didn't have a bunch of turbulence whenever water was cycled in and out.
Too hot of water, yes, on my boat, we use waste heat form engines to heat the water. However that temp goes to about 78C, so it keeps it pretty hot! With only 11 gallons of hot water, being that hot, it limits usage pretty good and allows much longer use of the water before the need to run the generator to use the electric side. The hot water will remain hot for days. Funny seeing a "split" system, as our heat pump systems in the US are all in one units with the heat pump unit sitting on top of the tank.
9:58 "you don't want it too low because then you're using too much hot water to get the temperature that you want"
Huh? The amount of water taken from the tank remains the same, the only difference is you mix in more cold water at that point (the standard thermostatic mixing valve) instead of at the tap.
For highest efficiency set the temperature as low as possible while still able to get the temperature that you want and without any in-house thermostatic mixing valves/taps start to oscillate.
My only question, why use outdoor air for the heat? One of the benefits of a heat pump hot water heater in a hot climate is that you can get free cooling in your house!
Why didn’t you install an air handling unit inside your house to capture the refrigerant charge of state by recording heat from inside house to cool inside and put the heat into the water tank?
Hi, it's not my first time I put a thumbs up on a great video.
But this is the first time I turn 999 thumbs up into a 1k
Just sharing the little glimpse of joy!
Great video. It would be ideal if we could dump thermal energy from a refrigerator or air conditioner into a water tank for hot water.
With a fridge your dumping the heat into the house, air conditioner would be worthwhile although if its reverse cycle during winter you would cool your water.
You can, just place the heat pump next to your devices producing excess heat. They're people using a hot water heat pump to cool a wine cellar in their basement or using excess heat of a combustion based central heating/barn/server farm/household appliances. Of course if you care about the temperature in the room it's advisable to have some control over the airflow. You probably wouldn't want to do this in a heated room like a kitchen in a moderate or cold climate though...
Dave loved your blog, maybe you could comment on my experiance, I just had a Chinesium $2500 heat pump installed for $99 in Kincumber I have 3.3kw solar no battery, SO I programmed[installer did not set] to operate 9am to 3pm which, so far, has used the summer solar. My concern is the winter, the unit is set to just 65°C, not much headroom. The unit does have 1.7kw full freight heater which is selective to off. Bottom line, using solar [I see on last bill I have used some of the 222kwh feed in, there is only a change of $5 on the total bill for January. My old heater was 10 yo, a new heater for $99 is a good deal. IF it dies and no warranty I guess an off peak original will go back in. The subbies were doin 4 a day, my job was acceptable but sketchy, the electrical would not pass regs IMO but OK, the expansion valve drain will discharge on your feet, not legal but ok as they would say "existing" PS they reused my expansion valve insulation kit, just 600mm foam on the discharge, our villa is 34 years old, no pipe insulation, BUT lots of fibre in the roof, the 3/4" line is too big, holds lots of water to go cold, takes 30 seconds for hot water to reach taps. I intend to rerun the hotwater lines in 1/2" PEX, with a return loop to the tank as it takes 30 seconds for the hot water to reach the taps what do you think
You showed you outdoor AC units at the beginning. Don't they literally do the same thing as the heat-pump?
So why is there no standarized mix-and-match system where one can just plug in any outdoor unit to any consumption device (water heater for warming, indoor AC unit for cooling)? And since heat echangers are quite efficient: why do we still connect the heat pumps with their respective devices with refrigerants? Wouldn't it be easier and safer to use something like glycol or even plain water?
What is the average price per kWh in Australia these days? Are you affected by all of sky high energy prices in Europe or is it still normal? In Norway we used to pay less than 5 cents per kWh for the last 20 years but now the prices are sky rocking. .30 Euro today and rising, estimated to reach 2 Euro per kWh maximum during december and january...
Another way you can Add Efficiency Is Burying A Coil Of The Cold Water Pipe 10 feet underground And That Would HEAT The incoming cold water up 20 to 30 points
That's weird. When my Reclaim was installed they used the GPO for the controller but insisted on hard-wiring the heat pump itself. I wonder if its a NSW/QLD thing
Weird. It's only 1kW with 2kW peak.
In NSW they re-used the existing wiring circuit & hard wired mine. Switching the breaker to peak at the board
Commenting half-way through: Just sadface that it doesn't co-exist with the air conditioner pump; with a clever valve arrangement it could use solar to pull heat from the house to the water and only dump to atmo if the tank is full.
Edit: So it occurs to me it wouldn't be difficult to duct the air-con hot air output to the heat pump input air (other than being ugly as sin). Seems crazy to dump that useful heat to atmo if you're just going to try to suck heat back out.
You could probably do somethign tricky like that if you really wanted to.
The heat pump produces cold as by product of heating the water right? Could you use it to cool the house in the summer?
If you installed indoors you could but then during winter your cooling your house.
Why not direct solar collector for water? Additionally you would have an Inverter to warm up the water at night, but a big enough reservoir should be fine. Because your panels are going to have 25% efficiency tops, through a DC / DC you are looking at 23%. With a water solar collector you are looking at almost 100% efficiency for the same energy coming from the sun. Should be cheaper also and I wouldn´t think freezing is a problem in the land down under. In case you mentioned this, I´m still watching.
The thing is, with a cop of 4, you get the same efficiency as a direct solar collector system, but he already has the solar PV, and energy isn't wasted when the water is at temperature.
Further there is the fact that this gets the water hotter than a direct collector system tends to. Had one of those before, and they can struggle. You can also boost from the grid when required and do so with the higher efficiency.
Finally if you live in an apartment, this can be installed, whereas you can't do that with a direct capture system.
Makes no sense to waste valuable roof space with a solar hot water collector that ONLY does hot water. Using the space for solar panels can supply the EV, the house, the hot water, and everything else.
@@EEVblog And you mentioned that in the first minute of the video!
@@varno yes but usually you need to get the water up to 50C normally, in winter where the temperatures outside are around freezing (depending where you live) getting a cop of 4 is difficult with such a delta, but on a sunny day you can store enough hot water for the day.
Even better inverter air-conditioning struggles in winter just to bring the output air around 30C and these heat pumps are essentially the same type of system.
It makes sense to have a heat pump as an alternative as it's not going to be sunny every day or might need more water one day.
In the end you could also use the system to warm your house so you get even more for your money, but generally I'm more in favor of diversifying your sources.
@@TrickyNekro I think you have been using older systems with worse refrigerants. This uses supercritical co2, which is ideal for these higher working temperatures, and is also well able to work down to colder temps too.
Further this is an air-water heat pump system, so there is more efficiency in the condenser unit too.
Wait heat pumps work better when ambient temps are higher since they can warm the refrigerant easier. That's why until more recently heat pumps that aren't geothermal haven't been considered feasible in cold climates.
Thinking through the thermal dynamics maybe the higher energy transfer into the refrigerant makes the pump design less efficient. Might have to whip out the termo books and see what's up.
Either Dave just got this completely backwards, or I'm taking crazy pills. Even the graph in his video at 33ish minutes shows that the COP rises with ambient temperature ruclips.net/video/DO9uccP49_g/видео.html
Heat pumps somehow becoming more efficient when the temperature difference is larger seems evtremely unlikely and I'd need to see a detailed mechanism to believe that this would be the case.
For additional evidence, each source I looked up on the internet also said that heat pumps get better with higher ambient temperatures (assuming you're using them for heating, not cooling, where of course the opposite is true).
Also for some of the heat pumps COP drops when outside temperature drops in minus degrees.