Inside CCHRC: Thermal storage
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- Опубликовано: 9 янв 2022
- 79% of the energy consumption accounts for space heating in a single household in Alaska. This video explores the use of thermal storage to mitigate the cost of space heating while pursuing the use of renewable resources to heat the living space.
In the fall of 2013, a 25,000-gallon tank was buried next to the CCHRC building addition. The CCHRC aims to heat the new building without the use of fossil fuel. Bruno Grunau, CCHRC research engineer, explains that the thermal storage will provide 40 to 45% of heat required to heat the building. Grunau, also shows what consideration went into the use of thermal storage in his own home in Fairbanks.
The irony of the BP banner hanging off the balcony
Thank you for this video quite a few good ideas i can use. Especially the fabric stratifier and the buried tank with just a thin liner
Awesome video and great explanation of how your system works.
Wonderful video, very good description of the stratification.
Fantastic idea !
Tank you so much for sharing !
👍
First time I've seen your channel, just subscribed. LOVE what your doing and looking at doing something similar. I may incorporate some of your ideas. TY for sharing.
Excellent setup, I will be building a more basic system to experiment on at home. Loving these different ways of thinking!
wow! fantastic intructive video! the stratifier is especially clever! I'd use a closed separated heat transfer system though with glycol as transfer medium. as a Swedish eco architect I think I can safely say this method will be very useful in heating with low environmental load in colder climates all around the world. thanks!
do they use an electric heatpump to further crick up the efficiency?
@@WillemsMathias Yes indeed. 4,5-5,5 COP dependent on the make of the heat pump (fex. water/water)
I've never thought of water stratifying like that, that's so cool!
I have a cool idea for a quick project for that tank;
Make a display and a line of thermo-probes that find the levels of water temperature changes, just like your diagram.
You could probably hack one togather in a couple of days with an arduino or raspberry pi.
this is the way to go! thanks for sharing
I’ve been plumbing for 5 years now and it’s sad how much I just learnt! ENERGY COMPANIES ARE EVIL. THIS MAN IS A SAINT!!!
Very impressive technology!
Is there a way to heat without using any wood to supplement? Would a larger tank carry you over? How many days of heat do you get with this system?
Hi Bruno, you told in the video about the data ; is that available. Please can you show us where the data is accessible? I did search for this kind of system to build next to our new to build home.
Maybe I did miss it some how; the water tight 1/8" foil, what kind of material is that?
Is there any follow up about the 25000 tank and appandages?
Do you have somewhere more info and data about your water box under your home?
Please let the info come!! Thank you.
Water without pressure has a limit to how much energy it can store. Whereas if you were using sand as the storage medium instead you could heat it to 600 degrees. And since it is a semi fluid you can get heat to stratify in it readily.
Which liquid medium would you use ? I've seen oil based video solutions but fire hazard and pressure explosions are a concern but if underground the risk is mitigated.
You’d have to use a considerable degree of solar concentration to get 600° either F or C, though obviously a lot more in the case of Celsius. I’d use air as my transfer medium but it would require some sort of pump for circulation. Maybe multiple, porous, ceramic risers for the stratification system as sand will not disperse heat along strata as readily as in water. Of course, if you’re using combustion as your heat source, 600° is easily obtainable.
Not sure if the greater complication would be worth it. Those high pressure air pumps could be expensive or dodgy or both, IYAM, and you might need a tracking array to achieve those temperatures.
@@q.e.d.9112 no. Use electric inductive air heating and pump the air through tubes. That is how Polar Night is doing it.
honestly people, we should simply be using nuclear reactors
But that's useless if you don't have a source reaching those temps. 90C is already pushing it with solar heating. They're not using electricity for heating; others doing it like that is very irrelevant.
if i unterstood correctly
he needs to nonstop burn wood in the winter to get his tank onto the used temperature?
so he can use that tank in the summer and doesnt need extra fuel based heat
is it usefull to do that kind of heating? why not use solarpower to get electrical heat?
Thank you so much for the video, GREAT implantation. Are there any data on the internet yet ?What have you used for electronic compenens for Control of the temps? The stratefire what is it made of ? Please make some updates. Greatings from Denmark
I would think any pipe that has fine holes in will surfice. Personnally I would keep the tank water separate and use indirect piping as a heat exchanger. So the tank water never leaves the tank.
@@dcawkwell how can you then get the stratification?
Nnn. Ok I boo I Kp p PLLC
@@ybaggi You just have coils that reaches over the layers, it has the same effect. The water that circulates in the floor heating will coil from the bottom to the top that way the cold water leaving the floors will incremently get hotter as it moves up in the coil. You can also place the coils in different levels depending on your heat source. The solar collectors wont heat as high temperature as the masonary heater for example. But when you have this many heat sources and usages it sure is clever and flexible to use that stratifier sock he has.
Great work! Please work to simplify and reduce costs.
Thank you!
Hello: I am interested in how well the water stratifying sock is working? Any info you can send me would b great! I am considering doing a similar water storage idea. thank you, Ben
How do you calculate the volume of water or sand you need to heat the structure for a given time? Is there a reference for BTUs per pound of storage substance?
Really cool setup. Perhaps in the future you can try to get more thermal storage capacity out of that tank by utilizing the latent heat of fusion also. And combine that with a heat pump.
@Tom WaterFooler latent heat from the water turning from a liquid to ice, the phase change.
Historic hotel In Colorado- We have an large boiler tank that we are thinking about spray foam insulating, filling the tank with sand or rocks and burying under an outside dual purpose music stage/coffee shop seating area,. We have plenty of sunshine and hope to provide at least some some degree of heat during the winter. We would like to find a use for this tank, and expand our outside activities.
Superb.
and what happened ? how many wood is gone for the winter? how long the storage holds between the burns ? 2 - 3 - 5 days?
I'm looking to advise a customer on replacing a fossil-fueled boiler with a heat pump. The Daikin Altherma system looks promising. Daikin has many high-production info resources, but not much boots-on-the-ground how do you install and configure it type information. My main concern is matching the existing cast-iron-radiator system to the heat pump -- or replacing the existing cast-iron radiators with Altherma convector-radiator units. Would I need to get new electric to these, to operate the convecting fan? Is the fresh-air pipe needed for proper operation of the unit for heat-only (or for cooling -- to manage condensation or what?)
Well…
Nice project sir… this is great NEWS for anybody in the US and Canada… maybe …
Here in Europe/Germany about ten years ago, a engineer build himself a new house and had the same type of storage tank sitting in the middle of the house… he actually build his house AROUND the tank … and is for over ten years now not only energy self reliant, but his house is using LESS energy overall and he is in surplus… married with two kids … all the usual appliance.
Curious how top of tank closes up ?
Very interesting concept! Here in Sweden we use geothermal heating with deep vertical bore holes. I'm curious if you know how your system compares to it?
The deeper the better. The earth is warmer there. Free warmth. This system here needs the warmth to be put in first before you can extract it.
good job! 👍
I don't know how the copper pipe would react to it, but way more heat can be stored in the same water volume with potassium nitrate and sodium nitrate salts dissolved in the water. I think 40% potassium to about 60% sodium mix being most effective and of course, the more dessolved in, the more heat it can hold. I don't think they're near as corrosive as sodium chlorite (seasalt, table, common salt) and they are good fertilizers.
Mmmm tasty, im definitely hiring you for my plumbing needs.
how you prevent humidity coming to house? If you put tank under ground and if it leak heat to ground that ground will be warmer than cellar floor. That wil push humidity from ground to building.
Show the url to the heat balance calc... rhetorical?
Definitely interested in how this is working out, would love to do something very similar just south of you.
Is the tank cheaper than using a borehole to store heat?
Why do you need the stratifier sock? What happens if you don't have it? - Wouldn't the water move by itself per temperature & buoyancy?
I remember years ago the Japanese company Toshiba I believe is the one that was trying to develop these RTG devices which would provide heat for at least forty years and do it safely. That will be a perfect solution for a low pressure heating system that would last a lifetime.
...except the power levels are likely way too low, or the price so astronomical, or those combined with the containment concerns involved with radioactive materials that would make such devices unsuitable for much other than space probes and a few other rather unique circumstances.
So I looked them up and I can’t find any details about this project on there website…
How hot do you run your tank, and how hot can the vinyl liner and the Styrofoam withstand?
máš to ve videu ty cype
Maybe consider putting a "Greenhouse" outside and Surrounding the Primary house, to also allow a Growing Space in the Mid Space outside the house, but inside the Greenhouse?
I've see such in both Norway and in Sweden, on RUclips! Alaska should be similar benefits!
I am fascinated by all this, but go back to comparing all this set-up to just having buried air tubes to harvest Earth ambient temp air (55F in Wisconsin) to feed into a high efficiency heat exchanger (Mini split) system in winter with solar and batteries. Adding reflective material in winter months to harvest more lumens, remove in the Spring. I agree, start with a building that needs less heat and cooling (SIP'S are 2 1/2 times stronger and 15 times tighter than stick built) and add these systems. I think I would go with a sand battery under the house "charged" over the summer and fall.
how much maintenance would it need ?
how is the system worhink, after 1 year ?
I’m in a slightly warmer climate in the mountains of Japan, and am about to build a ducted air system using a sand battery of 3 cubic meters with solar panels running the heating elements.
The idea is to get the core above 600 degrees Celsius, and top it up on sunny days, i wonder how they’ll compare?
How has this system worked for you? I've been thinking of doing the same. Ty
Tiur outdoor water tank : shouldn’t I be standing up to better separate the different layers of warm and colder water ?
Nice system
how thick is the 25000g tank insulation?
awesome indoor pool
So wats the total cost ... to install
Are there any calculations that show how much of the winter heating requirement this storage covers ?
I'm guessing not very much.
Alternatively, please advise of water volumes, insulation specs and solar panel output, so we can do our own calculations.
yeah, its called thermodynamics
mass*specific heat*temp=energy
assuming a spherical chicken in a vacuum, the results follow easily. However including the various losses and other poor assumptions take it from 5th grade to phd real fast
@@5347robo I studied Engineering, so am familiar with thermodynamics 🙂
I just would like to see some evidence of the calculations for this installation, as most people just don't put a big expensive tank in their garden without doing some calculations to show how much energy can be stored and how long that will last for. So capacity as you suggest, plus heat loss, solar input calcs and requirements for the house.
If I do it, I need to estimate the volume of their tank, estimate the insulation spec etc. Would be far more interesting to see the actual calculations for this installation, with real dimensions.
I guess it might be more interesting in climates where there is more winter sun & scope for solar in that season, as I really doubt this will have anywhere near enough capacity or insulation for a proper winter season with less sun.
@@jxj2684 ah, I see I too would like to see the real world performance data.
It doesnt look like they cut corners, so I would assume its relativley efficient
08:26 - How long will that weave stay free of limescale?
So you want to match the incoming water with the right heat layer in the tank so you don't dilute or average out the whole tank I take it?
Correct. If the bottom half is 70 degrees and the top half is 150 degrees you can still effectively heat using the 150 degree water. You need a temperature difference for the water to do any real work.
If it were averaged out to 110 in the tank then it wouldnt be hot enough to use for thr domestic hot water and it would not fully heat the house either (though could still perhaps keep it warmish).
Think about your water heater, it does this same stratification. If you are taking a shower youbare happy as lon as the water comes out hot right? Maybe there is only 5 gallons of hotnwater left in the tabk, but younare happy. If it were all mixed up partway through the shower and the temp dropped to 75 you would no longer be happy with the showet
What does it give you one or two days of heat?
I have thought about using solar water heating, but always come up against water freezing in the exterior system when it is not producing heat. How are you able to overcome that barrier in Alaska?
The most common solution is using a glycol water mix. The glycol drops the freezing point way down but it's more expensive than water. Another low tech solution would be a drainback system. Basically a valve opens and all the water drains down to an insulated tank. A problem with a drainback system is that if installed incorrectly not all water will drain and there will be ice damage.
My system uses 50 percent glycol as you would use in a normal Car radiator, it’s not a problem in solar heating systems these days.
Mine is from a German company called “Sonnencraft “
Don't be nuts! How could you ever afford to build it and then let it freeze? This is inter seasonal storage, and once it is warm you would never allow it to get to freeze. You would pump it out rather than incur the cost of glycol. You could however make a business case for a PCM at about 50'C.
I'm looking to utilize a liquid to liquid heat pump system, 3 reservoirs 1 hot ,1 cold,1 neutral. Each faucet should have a return line for flushing the undesired water temp out of the pipe. When point of use reaches temperature solenoid opens allowing water to flow out of faucet. I thought about applying such a system to the fridge, A/C, etc. Utilizing a central heat pump setup would greatly help efficiency imo. Imagine a central geothermal heat pump system for a small neighborhood. Maintain it just like an essential utility like water or gas. Energy use on the grid would be dramatically reduced, especially if the system was powered via solar.
Great idea for a cold area. I do just the opposite for a hot area
What are the caloric losses from the tank walls?
300mm EPS 0,114 W/(m²K). Tank area is 24m². So it will leak 2.7 watts every kelvin/centigrade above ambient. So when water is heated to 60C (140F) then tank leaks 100 watt. Luckily almost all heat leaks into the house so it's actually not a loss, rather a useful heating.
I am interested how it works for you. I have never heard of a stratifier. One problem I see though, is that water conducts heat extremely well. Also moving water around in a tank, even if it is injected at the right level will cause currents which will cause the different layers to mix. You will likely have to heat up large quantity of water in order to heat up enough water to heat the coil. That will take a long time, and by that time the tank will be at about a uniform temperature.
I does not work like you mentioned, a warmer water acts like an oil and water, the layers in the tank never mix with each other. This is convection principle or whatever it's called. The heat accumulator should be always heated up from the top to the bottom, I mean, using the main source of energy, so you always have the energy available from the tank even if the tank is not fully "charged".
@@udaizd You are correct, it's the same as normal hot water immersion tanks work in the home, the hot and cold water split with all the heat up top, and we have been using this system for over 100 years now.
@@udaizd This video shows the mixing of hot and cold water. Also the dissipation (at least somewhat) of heat over ten-minute period. In the original video it would take probably take two days or a week or a month or something like that to get enough hot water. This would allow for a lot of dissipation of heat even if the water layers didn't mix.
ruclips.net/video/H0xB15fNzHc/видео.html
The Thermal mas was 8' x 9'' x 10' 720 cubic Feet.
Why not have done a 20' x 20' x 2' (800 cubic ft) 'sub-sub floor 'slab', since you were building up anyways?
This would given you have options as to how that heat gets up through the subfloor (air circulation path, floor heating circulation (lass draw horsepower for lift needed over lt) . Dual 10' x 20' x 2' can be done, depending on the sub floor, or if the bottom of a basement area, even as a greenhouse floor. Done using the same design as for a slab containers. Circulation of a store to release differential system can be done from the house wake/sleep south/north areas back/forth to regulate. Straight copper manifold is more efficient transfer of heat than the single coil method.
What is R-70 walls and R-115 ceiling?
Yet it is still oil and chemicals that give you steel, solar panels, etc. Green is good and needs to be our goal but we must learn how to make oil more efficient and less polluting because it is still the key to all the other energy sources, even when we reduce our dependance upon it. This was a great video.
R1.15 in the ceiling? In Belgium my ceiling was insulated to R1.7, about 5 years ago, and it was deemed insufficient in the building report, so I put another layer of insulation to bring it up to R3.20 which is the most common now. I can't imagine living under a R1.15 ceiling in Alaska! 🥶
I think it’s in inch pound units. R-115 is the equivalent of 20.7 m2K/W
He said R115 in the ceiling and R70 in the wall, not R1.15. It is R values in the inch pound system because he is in not america. The R value unit there is in (°F⋅ft2⋅h/BTU) the metric R values are in (K⋅m2/W) the conversion is the R_metric * 5.68 = R_inch-pound . So the insulation in metic R is R 20.25 for the celing and R 12 in the walls. So the celine R value is around 12x higher then you have.
Don't really get how you're going to prevent conduction from equalizing your temps within days .
Bad audio everything unclear . why the huge tank outside ??? When you have the tank inside ?
Sorry why when you speak off green energie, we can see the logo of BP ??? On one of the first image of your video.
How are you handle the pressure differences when the tank is heating up?
volná hladina cype, liquid pressure=atmosferic pressure. Did you seen all video
Why is the Storage Tank not buried deeper?
Cost ?
Any concerns about Legionnaires disease? Algae growth?
Because it is a closed loop system the water in the tank doesn't get extracted. Fresh water flows through the heat exchanger (copper pipe spiral) in a just in time, as needed for showers etc. Heat exposure time is too little for Legionäre bacteria to occur. Most algae problems occur only when the water is exposed to sunlight which doesn't occur in his system.
I wonder what it cost to do this... Anyone know
So around that water tank is concrete?
Nice how much did it cost?
how about putting it directly in the house
What is the CO2 equivalent effect of using spray foam insulation instead of blanket insulation?
neser s CO2, aspoň něco týpek dělá.
I did a quick calculation on this tank. From the volume I calculated the area of the tank to be approx. The insulation is perhaps 2"-4", 5 tol 10 c, The area approx. 130 m2. The insulation used look like something that have a Lambda = 0,038 W/mK . To get any meaningful heat form the water it need to be above 20C. This means a dT of at least 20. So, the lowest heat loss from the tank to the ground will with 10 cm insulation be 1 kW. Hopefully the peak can be 40C in the tank, with a heatloss of 2 kW, or close to 50 kWh/day. If you take heat out of the tank to heat your house and hot water, the tank will most likely be "empty" after 45 days. Any link available to the online data mentioned to be available?
I am not a native English speaker but will try my best.
You are missing a crucial point in the insulation theory. After some years a heat gradient will be created around the tanke effectively making the dirt work as insulation. You should take the temperature delta between the exterior air and the tank water. Then you will have an additional 10 meters of insulation once steady state has been achieved.
Look at, Borehole Thermal Energy Storage you only insulated the shortest distance to the air. The rest is considered thermal mass and insulation.
@@arvidjohansson3120 , I am aware of borehole energy storarge, and the effekt will kick in for this tank to. How much hard to say. The best way to put the tank in to ground to get benefit of the heat going out intp grouund would be to digg it down vertical, now horizontal to much heat loss upward to the air.
I’d love to see you add “health” and “air quality” sensors to this. From what I’m looking at, there’s a potential for bacteria issues, and maybe radon from the basement(?). Just spit-balling challenges. Love most of the design overall. As others have said, I’d be curious about how using a molten-salt form of energy storage would change the dynamics. All the best to you.
Maybe UV lighting inside the tanks to control bacteria?
I'm unsure if bacteria will really be a problem. The potable water is completely contained in that copper coil heat exchanger. The in-floor heating and solar-thermal panel water is the only water that is cycling in the main body of the tank.
nice. used thermosypion shower and laundry for years.. no problem with 160 degree water...
scald guard shower! salvage electric water heater... 2 3x7 boxed and glazed panels .. big tank stratification.. next is sand battery. dc direct.. for hvac
@coldclimatehousing I'd just heard about sand batteries in Finland
I have did see Sand because you can heat it over 500Deg C so better as water and longer storage !! What you think ??
I wonder if that tank would work better filled with sand and the water ran in a closed loop...
Idea to consider is wood chips and vegetable oil wick 👌🏻
Wouldn't the polystyrene and vinyl liners start leeching chemicals into the water due to all that heat ?
no problem, drinkable water goes trough that coil and never touches with tank water.
What is your opinion on sand or salt as a battery instead of h20. Both store so much more heat than h20.
Actually, sand holds 5 times less energy per kilogram. Water holds 4186 joules per kilogram and sand holds about 800 joules per kilogram. Sand can go higher temperature, but you're not getting above 80°C with flat plate solar heat collectors regardless so there's no point, water is the perfect candidate. And it's pretty much free and can be moved around much more easily in pipes.
Another problem with going higher temperature is the the hotter something gets, the faster it loses its heat to the environment.
wow , wow !
I'm looking in net of the fabric stratifier, and can't find. This is your solution or You bought it at the market?
I was wondering if there's a brand or source for fabric stratified as well
It looks like under tent breathable fabric sock...
I read some articles, and found that sbdy used Nylon 6-6 den200 fabric.
@@averon-off-grid Nice from you to share !! : )
Very interesting system. Please let us know when performance data is online for viewing. (Hopefully your instrumentation system is as well thought out as the space heating system itself.)
At the end of the day, it's the system performance data over time and in various outside temperature scenarios that is where the rubber meets the road. Green technologies have to work and deliver at cost/btu. Plus there is the question of embodied energy in the materials used - systems have to be widely deployable to begin to make a dent in global energy impact.
Still, every creative experiment is a learning opportunity, no matter how it turns out. Hope you'll freely share your performance results so we can all understand how things are performing.
P.S. I encountered an interesting experiment in small, passive solar heated shelters for homeless people that didn't seem to work and I have always wondered if the problem was thermal stratification. If so, it could have remedied with a little solar PV powered computer fan to force the stratified hot air at the top of the shelter to mix with the cold air at floor level. (Sometimes an idea is almost at the finish line and just needs a little tweak to work reasonably well.)
Hopefully you've thought of everything in this cool (warm actually) system design...
Add a Phase Change Material (PCM) to your hot water tank for a boost to your heat storage. If you could find a source of cheap wax, fill a number of balloons with it and toss them in. That would add an additional 200kJ of heat per kg of wax as long as the temperature of your tank stayed above 130F long enough to melt all of it.
😅😅😅😊😊
7:25
7:25
7:25 7:30
8:01
molten salt is a good thermal energy retainer and transfer medium used in solar farms.
if the tank could be pressurized to only 5 psi then a cryocooler could provide you with liquid co2 in the summer that can be used to not only spin a turbine as it expands but also provide cooling for the house..using solar power to run the turboexpander could make it net zero or even positive
I'd love to see your calculations and hate to write cheques for materials and installation for what you describe. There is no suggestion we need electrical generation from the client here. Surely using solar and to run a heat pump would be better if heat not electricity is the name of the game.
Can someone explain me what is that 7:30 white condom for?
Tank not buried fylly below the ground trips my OCD
if the tank is buried at 6 feet then the constant temp should mean that the water inside never drops below 58 degrees.. meaning you are only having to heat the water 12 degrees F or so. or even if too expensive to dig that deep thermal ground loops that only open once the water temp has dropped would accomplish the same thing??
Except in Alaska they still have permafrost
It doesn't look like its insulated very well to me.
Can someone explain me what is that white condom for?
I want to do the same, but to charge the "battery" every day, not an entire season. I want to use a tank for 1000 liters
Who came up with a pressure sock idea? A small wind turbine or solar panel running a water pump activated by a thermostatic switch would run the water only when the sun is up for recirculation or when programed differetly. A copper coil of pipe wrapped around the chimney of a rocket stove would heat up all in floor heating if the ground collection stopped working, fyi.
How do we flip this tech around to cooling homes in arid deserts ? And : Is it possible ? Is it viable ? Is it easily constructable ?
Use solar electricity in the Winter to run a chiller to freeze a giant block of ice. This way you get the benefit of having phase change which allows more storage of energy with less space. The main issue is the expansion when the water freezes and dealing with containment. Maybe just freeze giant blocks floating in a insulated pool so the water doesn't freeze near the containment walls which allows the water level to rise instead of freezing and pushing the walls out.
Here is my idea:
Build with ICF construction. Usually it has horizontal rebar every 24" but it has rebar hangers every 12" so half way between the rebar put in horizontal PEX tubing similar to radiant flooring but in the exterior wall. Maybe cheat the PEX toward the interior side.
Manifold all of that in a way that individual loops can be isolated if anything starts to leak.
Now outside bury a large geothermal PEX loop about 10-12' deep.
Fill the system with water and antifreeze and circulate that with a pump.
The thermal mass of the concrete in the walls will make temperature fluctuations slow and the ground source water should fluctuate probably between the high 50s and low 70s. With foam insulation on both sides of the concrete, thermal gradients will be formed, one on the outside going from essentially the outside air temperature to the ground temperature and one from the ground temperature to the inside, through the foam to the inside air temperature.
If it works the way I imagine, it should greatly reduce HVAC requirements because it will use that ground source without needing a heat pump, then your AC/heat pump is only working to adjust your temperature between ground temperature and your thermostat setting.
I just wish I knew an engineer who could tell me if it would work and help me size the ground source loop...
I'm confused about the focus on renewable energy sources instead of using readily available resources. While I understand the importance of energy efficiency in order to save money and make our energy go further, I don't see the benefit of adding an additional layer of complexity by relying on unreliable sources of energy.
Have you looked at sand for your energy storage rather than water....much more efficient as you would heat the sand box with hot water from your panels and heat the building with a coil in the sand also.
If l am correct a city in Finland uses this method to heat all the residents buildings!
To je dobrý úlet. Kdyby si raději za ty prachy postavil pasivní dům, nemusel topení řešit. Jen je potřeba navštívit takový dům a přepnout ze starého myšlení na vytápění na myšlení úspory a využití energie a trochu se uskromnit v rozměrech domu. Já takový dům navštívil a jsem z toho nadšený, venku bylo -1°C a uvnitř bez topení seděli v kraťasech v 22,5°C. V krušných mrazech musí přitápět rekuperací. Spotřeba celého domu za rok 6MW. Podpořit to ještě FVE, tak to bude půlka. Pecka a budoucnost energetické úspory. Jen na to stát neslyší, ten podporuje uhlo/plyno/elektro barony. Stavit dnes dům, měl bych jasno
6MHh