DESIGN: DIY Truck Camper Van Build Hydronic Heating | Air Water Floor Tanks
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- Опубликовано: 18 сен 2024
- Adding hydronics to your van build or upgrading an RV or Camper heating solution?
We're upgrading our heating system by adding a fully featured Hydronic Heating setup in our DIY flatbed Truck Camper for a variety of reasons:
-Improving our cold weather options with inexpensive heating source
-Adding radiant floor heat
-Leverage the free engine coolant to heat water
-Grow our hot water storage
-Improve heat sources in our external bag boxes
This hydronic heating system contains a lot of automation to control heating from the engine coolant or our diesel heat exchangers.
This video walks through the full system design and part 2 will take you through the install.
Love the way you've laid out your system and modes! Makes explaining the system so simple.
Great concept and great build 👍 Hope to implement some of your designs in my own build.
There is a PDF with a more complete writeup of the concepts and rationale with material detail at WorkingOnExploring.com/TechDocs
Nice! Looking forward to the install!
Thanks...its been quite a challenge because of tight spaces being so hard to film.
Thank you 👍
Very interesting
Nice layout and explanation. I’m looking at building a small (500 cubic foot ) pop up truck camper. No water system. I was wondering about a hydronic diesel system vs air diesel system. I like the concept of using the truck engine to pre heat the camper, also wondering if a re-purposed auto heater core with fan would work inside the camper. I realize the hydronic will need both a elect water pump and a fan, I also realize if the heater core is mounted exposed it will radiate some heat without a fan. I will use manual ball valves to control the truck engine coolant flow.
I think that is valid thinking. Anyway you can use waste engine heat is good....40 years ago, I had a pickup with a camper shell that I took an entire heater assembly (core and blower) out of a car and mounted it in the back with the hoses through the floor and it worked very well when driving. It was a solution to drive from college in MA to home in MT on winter break with people and cargo in the back.
1) I have and love to use my 5kW diesel air heater but if you were to go that way, get a 2kW unit. The soot up when running on low and unless it really cold, it slows down to minimum pretty often. My 5kw is too much even for my space and I have thought of downsizing it. I think no matter what you do with an engine-based heater, you will need something that works at other times and the redundancy of a diesel air heater is good.
2) With objects in the space that can absorb the heat, it will stay warm for an hour or two (I had no insulation anywhere) but otherwise it cools down pretty quickly. It might be interesting to just have a large(r) coolant tank in the back (size/shape of a steel 5-gallon fuel can?) that gets to 200F on the drive. thats a lot of thermal mass you can heat quickly. Put insulation around it with a small air space. Blow air into the space with a variable speed fan and have an outlet so you can control how much heat comes off of it. With this you could both preheat and store some heat for later.
3) A vehicle heater core would work fine but the squirrel cage blower is noisy. I would use several 'high static pressure' 120mm or 140mm low speed (1800) rpm fans. These are specifically made to move air through water/ air heat exchangers that gamer CPU cooling systems use. Auto heater blowers operate with engine and road noise so don't need to be very quiet. There are any number of these auxiliary (heater core and fan in a metal box) heaters on eBay but they either use squirrel cage fans or standard computer fans that blow little if they have to push through the heat core. You can identify a high static pressure fan because it has more, broader blades that almost fully cover the fan arc. Do a search for them and you'll see what I mean. I use this one; www.amazon.com/gp/product/B07CG2PGY6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
and this one
www.amazon.com/gp/product/B08T183TJR/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1
Great setup! I've seen similar setups, not as complete as yours, that use the calorifier and ALSO include a coolant expansion tank? If there is enough space to install the expansion tank - is it beneficial with your setup?
I have a small, pressurized coolant tank (pressure relief cap on a radiator overflow tank from a Cooper Mini) that I theorize is adequate for expansion when kept half full so I didn't install a bladder tank on the coolant side. On the DHW side I have two RV 'accumulators', one at the pump discharge (deals with pump pulsation and cold water buffering) and one on the calorifier inlet, ahead of the reverse flow check valve to deal with expansion in the hot side of the calorifier.
I am not absolutely sure that the coolant expansion tank is adequate in every situation. I have experienced a couple of minor coolant leakages over the past couple years I can neither find nor attribute to a specific event so I am contemplating installing a small bladder type expansion tank just in case there actually is a pressure problem I can't specifically identify.
Well done, I’m enjoying watching all the build videos. You have some great ideas which are well executed. I assume your expansion tank on the hydronic system is pressurized to the same value as the engine cooling loop. Have you had any issues with vapor lock or purging air from the system?
Thanks!
The cap pressure on both the engine tank and cabin tank are 16psi. I'm sure that when the engine runs, it produces more pressure than when the coolant heater runs because the engine (often) gets to 230F but the coolant heater only ever gets to 90C/194F. I have not actually measured the pressure it reaches but know the cabin side experiences whatever pressure the engine side produces because I don't shut off both the supply and return hoses anywhere other than between the engine and calorifier. Because I want water heated any time I drive, these valves are open almost all the time the engine is on. I initially only had one valve between them and had a small 'fluid migration' problem where coolant in the cabin would, over the course of a couple weeks, overfill the engine coolant tank. This is why I added the return side valve at the engine which has largely stopped that (and it ensures that if I had a leak in the cabin hydronic side, I could isolate the engine to prevent loss of engine coolant. I may still add a return side valve to the cabin heat loop to prevent both tanks from ever being open to the other at the same time if the migration problem is not completely stopped (would need to show it is completely reversed from last time).
This system is going to be awesome after it's installed and debugged. I may have missed this, but are you able to have a mode where you can heat the cabin AND the hot water for showing at the same time?
It is done and works. The cabin heat by coolant heater and water heating by coolant heater are separate as you correctly observe. Running parallel circuits creates flow control problems where coolant can go mostly to one circuit or the other effectively making one work barely and the other work only fair. It only takes 10 minutes to heat a tank of water so while the cabin heat is running, I can just switch over to water heating for 10 min then back to cabin heat, likely without any discomfort to the cabin.
@@WorkingOnExploring makes sense. Can’t wait to see the video of this system functioning. Also, am I correct by assuming you will be using engine antifreeze as the “water” in the entire system?
@@SquarebodyTruckCamper yes. Because it is one coolant loop that is switched by the ball valves to operate in sections, it has to use the same coolant as the engine which is a 50-50 mixture of shell rotella extended life coolant and distilled water. To create isolation, I could have installed a heat exchanger between engine and cabin systems (which I have) but don't like the additional complication.
thank you for this great video, can this system swap the water tank by replacing the one i found call Incline Engine Heat Transfer Water Heater (4.2 Gallons) from van land? also i wish it can be operator by the LCD like the rixen's Hydronic Heating
All calorifiers are a water tank with an internal heat exchange coil for coolant. Some have two heat exchange coils. They are constructed in multiple sizes and shapes of the tank depending on the manufacturer and intended use. The one I use is cylindrical and the one you cited is rectangular. They do the same thing. The one you cite is very expensive ($1879 vs ~$600). Rectangular tanks are also not structurally as able to tolerate pressure as cylindrical tanks.
I'm not familiar with the operation of RIxen's control. They might be making a better-adapted control for use in RV's as I definitely think that is something that could be a desirable product but I'm also sure it won't work the same on all coolant heaters. Not all coolant heaters operate the same so that is something you should investigate thoroughly before you buy. You have to keep in mind that the primary purpose of most coolant heaters is to preheat a cold diesel engine and their controls will be designed around that. Some coolant heaters are designed for use as supplemental cabin heaters (such as for busses) and will have different control strategies than engine heaters. Similarly, use in RV's may create a need for either water heat or space heat, both of which require different control strategies. I have taken this all into consideration when selecting a coolant heater made to heat an engine and to build controls that make it useful to heat water, heat a living space, and still preheat an engine. My control system requires frequent hands-on and is definitely not a 'set it and forget it' automation. You will have to decide for yourself if what you want to do can be adapted by the control that your coolant heater comes with.
@@WorkingOnExploring thank you so much for the information and i think your system are far best i could ever find on the internet just feels if i can control them in one touch screen that will be to perfect solutions like this touch screen ruclips.net/video/ExoOEDlTz70/видео.html thanks again for your great information really appreciates your input.
I watched the video showing the Rixen system. It is clear that Rixen has developed its own control that manages the coolant heater as well as supplementary system pumps and 120VAC immersion heater. It is a costly system @$5,200. Rixen sells the controller separately for $1,000. It would not expect this to work with coolant heaters other than Espar but it could.
Wow that's an elaborate system, I have a couple of questions the heat exchanger that you're mounting underneath the truck how is that protected from below freezing temperatures? Where would I get the diagram that you built this system from?
The 'calorifier' (not just a HX) is made by SureCal and sold by 'Heatso' in the UK. It is a horizontal copper hot water tank (also has 120V/1kw heater) that stores 20l of water (other sizes and orientations available). it is insulated with rigid polypropylene foam. It is protected from freezing by 1) keeping hot water in it, 2) insulating and heat taping the exterior water lines that run to it 3) bundling the exterior water lines with the heater hoses that run 180F coolant too and from it when the coolant heater is running. 4) mostly the strategy is, to keep hot water in it, and using an asymmetric timer, I circulate water through the whole water system and back to the fresh tanks for the 30s ever 30min, 24/7 when the freeze protection system is turned on. The timer can do any duration on both open and closed from 1s to 100d so if/when I hit cold weather again and my 30s/30m isnt right I can easily change it.
The system diagram is available on WorkingOnExlporing.com/TechDocs about halfway down the first section on the left. See 'Maximus Hydronic Heating System Plan'. Its a PDF. Originally created in MS Visio if you want that, I can provide it.
I just noticed you posted 5 days ago...somehow I missed it...sorry.
One other note on keeping the calorifier from freezing....the default is to let it be heated by the engine whenever the truck runs. Since that occurs regularly (but not necessarily daily) and gets to 180F pretty quickly, even in freezing weather, I'd guess that running the truck 1x is good to keep it from freezing for 24 hours. When below freezing, I intend to use the coolant heater to do cabin heating because it also provides heat to the battery, gray tank and calorifier so I can run the fresh system heating...
I realized today that the hydronic system diagram doc on my website also includes a lot of written description and planning info as well.
Thank you very much for your detailed video. Do you have a link of where you purchase your Chinese hydranic heater? Are you happy with it? I’m looking for reputable seller
I am happy with the heater BUT 1) I purchased it with the 'new' control that wasn't described in the manual. I spent considerable time figuring it out and writing my own manual which is posted on; wokingonexploring.com/techdocs. I do like the new control and chose it because it was a not a membrane keypad (old one) that I don't feel are particularly reliable. It does have a lot of Chinese status icons which I had to get translated by a friend and still don't really know what they mean precisely (also in my manual). I believe I have a good enough idea where to start troubleshooting if one should illuminate. 2) I purchased it from www.aliexpress.com/item/3256803096628968.html?spm=a2g0o.order_list.0.0.21ef1802z4liPZ&gatewayAdapt=4itemAdapt
The reseller is 'szyiqitrading store' which I do not recommend. I asked them several times for help on the appropriate manual and was met with silence. It is made by and I would order from 'HCalory' (Hcalory.com), the Hong Kong manufacturer, directly. I believe they also have an aliexpress store. I also reached out to them for help with the control instructions and they responded quickly but would not help since I did not buy it from them. I am not too optimistic that they could have helped because I suspect an English translation of the manual is not done. The manual it did come with was particularly terrible (even as far as most Chinglish manuals go) but was somewhat helpful in divining what the functions were so I could figure out how the new control could do the same things. I did send them my manual and asked for their review/help and have not heard back from them. At this point, I don't expect to. I think most of the Chinese 'resellers' are likely to have no better tech support than any other, especially since I doubt that any technical support documents from any of the manufacturers exist. I do believe that a single electrical manufacturer is making the internal circuit boards and control panels for numerous 'manufacturers' of these heaters that are just making molds and reverse engineering the hardware from Espar. It appears the manual I got with my heater was written by the controller designer but only identified them in a round about way (no name, no revision , no date, nothing uniquely identifying the author). 3) Overall, I do like the heater and bought it because it appeared to be the most robust (and is is) . It is ALL aluminum castings. The coolant outlet elbows are fiberglass reinforced plastic (likely PPS) and work well. The wire harness is well made as were most of kit components. I did not use the inevitably cheap Chinese hose clamps but everything else was well done (I'm a retired mechanical engineer/manufacturing engineer). It did not include a tee to tap into the fuel line but everything else was there. 4) I bought additional exhaust pipe and a second muffler (amazon). It is not loud but does have a high pitched whine that needs to be muffled by something that I have yet to develop. I think I may open up the mufflers I got an pack them with glass fiber or find a small generator muffler that actually has some material inside it is likely to work. 5) The fuel pump is FAR quieter than the one on my diesel air heater and is just the loudness I want it. I can hear it if I am trying to hear it working but otherwise, is not noticeable. 6) The connection of the right angle coolant connectors need some special inspection/attention. They are held on by an ''X' clamp and single screw and sealed with two silicone o-rings. Both were improperly assembled/secured and leaked badly out of the box.
Hi. Fantastic video, well done! I love that you designed a system with all 4 mode options, this is exactly what I wanted for my campervan conversion but didnt know how to go about it exactly. I definitely have a better idea thanks to you, thank you! Could you send links to all of the parts used in your system please? I dont know where to find these & which are the right parts I need. I would really appreciate this as I dont know anything about the ball valves, mechanical switches etc but am trying to learn. I like you, want to be able to heat the water for shower, dishes etc from either the vans engine or diesel water heater or solar/batteries/240V (Im in UK). I also want to be able to include hot air in the campervan from the system, is it therefore possible to connect 4 hot air matrix vents to this system? (One in lounge area, one in shower, one in rear garage & one in front cab. I have an extended length Peugeot Boxer which is US Ram Promaster equivalent)? I'd appreciate any help & advice you can offer me. Thanks again for the brillaint informative video. Regards Tracey
Tracy,
Happy to help. The first place to look is on my blog WorkingOnExploring.com/TechDocs. About half way down in the first section is an area with hydronic info. Links for videos on the right and on the left is 'Maximus' Hydronic System Plan' hyperlink. Download the plan and study it. In there you will find a lot of information on parts and wiring diagrams although there is not a detailed bill of materials, there is general information. There are no specific links to material sources but some products are named and a search using the terms I use should be able to get you close. Much of what I bought was from Amazon or eBay. The coolant heater I bought on AliExpress. If, after reading through all of that, you have some specific questions, send me an email at WorkingOnExploring@gmail.com
Which pex manufacturer you recomend ?
I see little difference in the major brands. I think that RV systems get so much less use than residential systems that likely failure due to matrial reliability differences really doesn't play into the decision. RV systems are also typically more accessible and therefore more easily repaired. I use Bluefin (supplyhouse.com) mostly and have previously used Apollo (Lowes). I also don't get hung up on limiting myself to 'oxygen barrier' material although I use it where possible That is only a factor for systems containing steel or cast iron components which I don't have other than the engine block. Using automotive coolant/distilled water mix that contains corrosion inhibitors as also a reason to ignore it.
There are more likely several more relevant factors when choosing a piping system;
1) PEX-A vs. PEX-B; expansion fittings (PEX-A) provide better flow but are not repairable (only replaceable by cutting out) which severely impacts any ability to make field repairs. There are multiple types of 'crimp' clamps but only one that is easily removable and rated as reusable up to 3x and that is 'PEX LOCK' (not sure of spelling). Additionally, they also don't require a special tool (vise grip or channel lock pliers will do) making them far easier to change or repair in the field.
2) An RV is not a house and has shorter runs and far more challenging routing. I use 3/8 diameter pipe in my fresh water and some of my parallel hydronic circuits. It is flexible enough to avoid fittings between the supply hub and fixture. While I don't like push to connect fittings (mostly referred to as 'Shark bite'), I do use them on 3/8 pex to avoid significant restrictions of internal fittings.
what's the name of the switch at 5:00? I want to get one, couldn't find it.
uxcell 4P5T 4 Pole 5 Position 2 Deck Band Channel Rotary Switch Selector with Plastic Knob a.co/d/doHlnA0
This is a 4P5T (literally 4 pole,5 throw) rotary switch. The 4 pole means it controls 4 separate devices simultaneously. The 5 throw means it has 5 positions. To produce this number of outputs (4x5=20) it needs more space than a single disc can accommodate so it becomes '2 decks' meaning 2 discs on a common shaft. Depending on the number of devices (X) you want to control and the number of modes (Y), search for ' (X)P(Y)T rotary switch'. I got this cheap Chinese made one from Amazon for ~$12 (more now). It has very adequate performance for the relatively infrequent switching used. A high performance one will likely be over $100.
Each or the 4 poles of the switch have one input and 5 outputs (One for each of the 5 'throw's). In each of the 5 positions, the input is connected to the respective output. I connect a 24V positive (because my battery is 24V and I purchased 24V valves) to the input. The 4 valves are control type CR02 (important) and receive operating power with 3 wires (there are other control types with 3 wires that operate differently so be sure). You need to ensure you buy an appropriate control type valve. There are control types that are inappropriate (see the reference doc below). The three wires are one negative and a positive for open and a positive for closed. The appropriate positive is (open or closed) is connected to the appropriate output for the desired mode. There is a wiring diagram of the switch wiring in my 'hydronic system concept document' (or similar words) at WorkingOnExploring.com/TechDocs
@@WorkingOnExploring thank you so much, gonna start my hydronic project soon 😀
Which brand of Chinese heater did you use?
I have an HCalory 5kW, 24V coolant heater and really like it. I bought it after I already had a no-name air heater and wish I had also bought their air heater although my no-name has worked flawlessly for 3 years.
Thanks for the tip. In my case, I have a tiny 2002 VW Eurovan Weekender and I'm trying to design a simple, compact auxiliary heating circuit to tee into the existing rear passenger heater circuit fan while parked, currently its heat source is coming from the engine. I don't want to run the engine all night just to heat the small cabin area and I'd like to also have an on-demand water heater for outdoor showers as a bonus.
Your design provides a wealth of information, however it has way more capability than I require for my simple task. The Chinese heaters seem like the ideal fit, considering they are much cheaper than the German Espar units...factor of five. I'll likely go with that same unit, as you seem to have had success so far. Also, thanks for posting your video as it gives me some good leads to parts like the control valves which I will no doubt need to exclude the main engine circuit while running the parking heater. Your video is the best one I have found so far...no fluff just the straight goods! Additionally, I was thinking, at times I may want to include the auxiliary circuit backwards to the engine circuit to pre-heat the engine in freezing climates (Canada's winters). Those valves would be ideal. I wonder if you have any suggestions for this?@@WorkingOnExploring
You can reach me directy at WorkinOnExploring@gmail.com. I see you're wanting 3 things (in priority); 1) Cabin heat, 2) hot water, and 3) engine preheat.
Cabin heat may be challenging because a 5kW coolant heater is probably about 2x your need. Some people have sooting problems with diesel air heaters when running throttled down for very long. Coolant heaters also don't operate on interior temperature control like a thermostat-controlled aire heater. The way the coolant heater operates, you are not in direct control of the burner capacity. I don't think they make 2kW coolant heaters but they do make 2kW air heaters.
I can see an alternative if you are willing to settle for not having the engine preheat. I'd start off with a 2kw diesel air heater for cabin heat. Since you have engine coolant going to your rear heater, you could install a calorifier under the cabin and that would use that engine coolant to heat water. You end up arriving with great hot water for a shower. Something like this; www.heatso.com/surecal-horizontal-10-liter-2-64-gal-single-coil-calorifier/ they make 10, 15 and 20l versions depending on how much space you have and how much water you want. They are similar in price so if you have space for a larger one, you'd be advised to get it. I have a 20l and it heats up to 80C in about 20 minutes of driving (as long as the engine heats up quickly.....when really cold, it takes my engine a long time to heat up) and stays relatively hot for ~12 hours.
This combination keeps plumbing and operation simple. if you want to add a coolant heater to heat the calorifier, it is relatively simple to add valving to also get circulate it to reheat the engine too. Doing these two is not hard, but 3 or 4 things gets a lot harder to control. Probably the biggest problem would be controlling space heating. The coolant heater would be shutting down very often and your interior temp would be like a yo-yo. Rixens (Rixens.com) has a proprietary controller that consolidates functions. It's $1k and I believe only works with a Espar heater. They sell kits which are also VERY pricey.
PDF layout? List of components?
workingonexploring.com/TechDocs has a lot of technical resources including a 'Hydronic System Concept' document that goes dep into materials and strategy as the schematic for the system and for the electrical. If you have specific questions, email me at WorkingOnExploring@gmail.com
thanks@@WorkingOnExploring