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Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 12:12 pm
by cornfused
Now that it is turning colder, I am back to thinking about heating my trailer. I currently use a 1500w space heater with a built in thermostat when I have electricity handy, and a mr buddy catalytic non vented heater for use when electricity is not available. I am impressed that the 1500w space heater is able to keep my trailer nice and warm inside even with camping out in 10deg F with blowing snow. The Mr Buddy also works well, but I only use it as needed because burning the propane adds to condensation build up in the trailer.
Thinking about how Overthetop has experimented with heating via his water heater, it got me thinking about using solar water heaters to heat the trailer. These pool heaters really got my attention also.
http://www.target.com/p/aquaquik-solar- ... 10679233-2
Now I realize that adding gallons of heated water storage to a trailer will add some weight, and isn't practical for some of the builders here who really have to watch their weight, but I'm really toying with the idea of adding an insulated tank and putting one or up to 3 of these on the roof and seeing if I can get to the point of heating my trailer to a comfortable temp and maintaining it through the night. If all else fails I could add a heating element to the tank to keep the temp going via my batter bank at the early hours of the morning.
I need to do some calculations to see how much water I would need to have in storage to try and equal the 1500w that I know heats the trailer through the night...
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 12:31 pm
by cornfused
Ok, so If I figured this right... 1500w for 8 hrs comes in at around 41,000BTU of storage. Using this chart, if I can heat the water up enough to have a 50 degree temp drop I would need around 100 gal of heated storage to make this work. So is adding roughly 1000lbs to my trailer worth "free" heating? I'm not sure, but I think I could build a system to do it for under the cost of one of the diesel heaters like a Espar or cheaper Planar which is my other option since I'm pulling it with a diesel truck...

Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 12:38 pm
by lrrowe
cornfused,
I am investing the possibility of using a solar system for my water heat needs in my home radiant heat system that I had added myself during our new house construction. So I do have a little knowledge in this area.
I agree with you that you would need a storage tank and the fluid needs to be an antifreeze type so you could not even use it for regular water use. It would need to be a closed circuit. My plan for my house would require a 200 gal storage tank. Think of the tank as a buffer to manage the hot fluid for peaks and valleys of use needs.
But could you not use this heater coil with an Attwood heater that has the separate heating coils built into the heater. Then just run a fan across your heater coil device. The required explanation is a little more detailed then this, but hopefully it gives something to think about.
It fits one of my options I have considered for quite awhile.
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 12:56 pm
by cornfused
I was planning on using antifreeze of some kind probably RV or some other non toxic just in-case of leaks.
For heating, what I was thinking of using was a motorcycle radiator that I have laying around that already has a 12v fan mounted to it. I would have to look up what it's specs are, because I'm sure it's efficiency of heat transfer might be too low given the lower temp difference than the 190 degree engine temp it was designed for.
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 12:59 pm
by lrrowe
Were you going to use the motorcycle radiator with the fan instead of the coil unit?
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 1:10 pm
by Shadow Catcher
Other than the fact that "she who must be obeyed" is a fair weather camper... and we have an eberspacher heater. I have played with the idea of using the 6gal water heater an oil cooler as radiator 12 case fan and 12V solar heat water pump.
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 2:22 pm
by Rainier70
Fun idea and interesting concept, but besides the weight, there are the complications of dealing with a lot of plumbing that may spring leaks with vibration. It also looks a little spendy to me once you add up all the hoses, plumbing, pumps, tanks, chemicals, heat exchangers, fans, and solar collectors. How much more battery usage? Would you need bigger solar panels and batteries? I would also have to factor in the cost of my drop in gas mileage due to the added weight. I'm not trying to nay-say, because I would love to see this in action. I just think it is more for larger units that stay in one place for long periods of time.
For me, I couldn't do the weight or sacrifice the room for the water storage. I went with the very simple NuWay Propane stove. It has kept my ct toasty on even single digit nights.
Don't wait until it is too cold though......
http://johnhartstudios.com/bc/2014/12/0 ... er-8-2014/ 
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 2:37 pm
by hankaye
Rainier70, Howdy;

,

,

2X.
hank
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 4:05 pm
by lrrowe
May all be true, but isn't it fun to dream up these wild ideas and then throw them over the wall to see what happens.
Remember, Rube Goldberg was my mentor.
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 4:12 pm
by cornfused
Ya, I kind of doubt I will act on it, but I do think it would be a possibility, especially if you got creative with a heat exchanger in a hot water heater. Probably need to go "overthetop" on insulation also...

The other random thought I had to make it work was to put radiant heat in the floor of the trailer along with a lot of insulation. I would think you could get quite a bit of "stored energy" in the floor heating coils during the day and let it cool down over night. It would probably keep it above freezing in the trailer, but there would be some decent temp swings from late in the day to mid morning...
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 5:44 pm
by lrrowe
I too have thought about the in-floor heating, especially that I am using it now in my house. Heck, I even have the sub floor clearances and insulation already in place.
But what stops me is only the heat absorbion and release. Radiant heat warms the objects and what can we put in the trailer to absorb, hold and release the heat. Tile? No. Too heavy and would probably break loose with all the road caused vibration. Metal, no, too heavy and difficult to install ( for me at least). And I doubt that my 1/2 in plywood flooring with whatever I use over it will help. I will keep thinking about it and researching for ideas until I am ready to seal the floor.
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 5:57 pm
by KennethW
If you are thinking of using RV antifreeze It is not truly antifreeze as it does freeze. It just does not expand when it freezes as not to break pipes.
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 6:25 pm
by lrrowe
If I did it with either the Attwood heater with internal and independent coils I first would look at using regular water and draining the line after each use during freezing weather. This would be something I could do easily with a small portable 12 volt air pump. If I did use an antifreeze type fluid, I would research more into what the solar hydronic installers use.
Re: Random solar heating thoughts...

Posted:
Tue Dec 09, 2014 6:45 pm
by MtnDon
KennethW wrote:If you are thinking of using RV antifreeze It is not truly antifreeze as it does freeze. It just does not expand when it freezes as not to break pipes.
There is special polypropylene based anti freeze for hydronic heating. It's non toxic and required by law if anti freeze is used in any residential or commercial system, due to hazards if a spill occurs. It's not cheap.
Re: Random solar heating thoughts...

Posted:
Wed Dec 10, 2014 12:11 am
by OverTheTopCargoTrailer
WTF ......
..is this Enginering for NASA Mars launch here today
I told you guys already 100 times, get 6 home depot buckets $18, fill with 140 deg water
And your trailer will be boiling hot all night long. If its -500 F then just get up at 1 am and reheat
the water. The more insulated your water tank the slower the heat is released.
OTTCT ..... Uses 35 gal 120 deg F and keeps his little shack warn for 48 hours.
10 gal on Propane heats about 1,800 gallons water from 60 to 120 ......
Water heater cost $600 can do 7.5 GPM !!
Guys please try to keep it simple - before you try to heat the moon rover.