Wacky idea on a heater!!!

[steve wolverton]

This is what I bought. It has a bult in thermostat (60 to 80 deg) Wall mountable (removable for the warm season) and cost less than 20 bucks at Wallmart or Lowes. I plan to hang it from my cabnet door.

It looks like I'm going to be getting something like this as well. I'm sort of weird in that I have to have white noise to sleep well (fan, ac humming, etc.) and I was really hoping to find a 5000 BTU AC with a heater. The fan runs all the time so I don't have 'breaks' in the cooling or heating period. Last camping trip with a small heater caused me to wake up everytime the heater kicked on. That made for a long night. I wish I could find a heater that had a fan that would run even when the heating element wasn't on.

[Scooter]

Couldn't 12v lights also be rigged as small heaters? Although I'm aware 12v heaters are a big draw on battery power, I've certainly noticed heat coming from my reading lights and overhead light (and they take a looong time to drain my big ole trollin' motor battery). In a small 4x8, every little bit helps.

I'd leave 'em on overnight if it wasn't so bright. As my wife says, close my eyes, it'll get darker.

[angib]

Here's the 'hydronic' system applied to the Generic Benroy:



It's the water heater that takes up all the space - though of course it does also provide hot water!

I can't prove that the Toyota Corolla heater matrix (chosen just because the car is sold both here and in the US) is powerful enough , as carmakers don't publish heater powers! Gut feel says it would be enough, but there's space to put something bigger in.

The piping circuit needs some thought. At least two non-return valves are required (one on the cold feed and one in the heating circuit) and the water heater itself needs to be investigated to see if whatever it uses to protect against thermal expansion can serve the whole heating circuit - this is likely as we're only adding less than 1/2 gallon to the existing 6 gallon capacity.

Andrew

[bdosborn]

I can't prove that the Toyota Corolla heater matrix (chosen just because the car is sold both here and in the US) is powerful enough , as carmakers don't publish heater powers! Gut feel says it would be enough, but there's space to put something bigger in.

The piping circuit needs some thought. At least two non-return valves are required (one on the cold feed and one in the heating circuit) and the water heater itself needs to be investigated to see if whatever it uses to protect against thermal expansion can serve the whole heating circuit - this is likely as we're only adding less than 1/2 gallon to the existing 6 gallon capacity.

I have an automatic transmission cooler left over from an aborted tranny swap that I'm going to try. They're pretty cheap compared to heater cores. I've been looking at watercooling for computers to get an idea of what kind of parts to use and the typical computer heat exchanger is rated for about 350w or around 1,000 BTU, with fan assist. My tranny cooler is a bit bigger than the ones I've seen for computers so I figure it will work for an area as small as a trailer.

An RV hot water heater is different from a residential type in that its designed to have an air bubble in the top to accomodate thermal expansion. A common mistake is to pressure fill the RV heater to eliminate the bubble. As a result of this design, drawing water from the bottom of the tank and returning to the top works better if you're using a pump. Don't know how this would affect things for the pumpless design but I'm interested to learn how it would perform.

Here's a circulating pump I'm looking at:

http://www.sidewindercomputers.com/swmc12vdcpu.html

Its real easy to spend a lot of money on a DC hot water circulating pump...
Bruce
P.S. From the meager information I've been able to find, a typical residential thermostat contact is rated for 3 amps, so it should control a small pump and fan without having to use a contactor.

[ARKPAT]

angib Posted: Tue Oct 31, 2006 10:35 am Post subject:

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Here's the 'hydronic' system applied to the Generic Benroy:



It's the water heater that takes up all the space - though of course it does also provide hot water!

I can't prove that the Toyota Corolla heater matrix (chosen just because the car is sold both here and in the US) is powerful enough , as carmakers don't publish heater powers! Gut feel says it would be enough, but there's space to put something bigger in.

The piping circuit needs some thought. At least two non-return valves are required (one on the cold feed and one in the heating circuit) and the water heater itself needs to be investigated to see if whatever it uses to protect against thermal expansion can serve the whole heating circuit - this is likely as we're only adding less than 1/2 gallon to the existing 6 gallon capacity.

Andrew

Andrew That looks like a good idea. Althought why not embed the core piping just under the floor on a reflective foil on insulation ( shinny side foil facing up to the floor ) under the piping just like some houses are done; but smaller piping and less number of coils. Then set the heat range to lowest setting for the heater.

I'm not sure if it is overkill; but I might try it anyway.



Pat

[Endo]

I wish there was something with less power or had a variable heat setting below 750 watts. My tear is only 12 volt but it wouldn't be that hard to add one circuit of 110 volt. Danny

Here is a 12 volt option for you. It's 300 watts.
http://www.quadratec.com/products/92060_00.htm

[dacrazyrn]

Dee Bee posted this gem http://www.heatstick.com/
I am looking in to transforming it to use a 12volt bulb (and candle-since ya gotta love candlelight). Need to test which bulbs would give off a decent amount of heat to warm everything up and radiate it out.
thinking like an old hurricane lamp (I have 2 oil burners in my house with the reflectors behind) with a "tin shade" to block the light to sleep mounted on the wall like the above lamps.
with candle thinking of those 12 hour survival candles and a spring mech (like in my my trusty candle lantern to feed it up.

[halfdome, Danny]

I wish there was something with less power or had a variable heat setting below 750 watts. My tear is only 12 volt but it wouldn't be that hard to add one circuit of 110 volt. Danny

Here is a 12 volt option for you. It's 300 watts.
http://www.quadratec.com/products/92060_00.htm

This looks promising but will it overcome my two group 24 batteries connected to a 110 volt onboard battery tender? How many amps would 300 watts draw? The best heating option we have experienced so far is two extra 30 deg sleeping bags over the pair of 30 deg bags we are sleeping in. It dropped to 20 deg last night but the garage was about 40 deg. I pre-heated the tear with a MR. Heater on low for awhile, we were very warm. Danny

[bdosborn]

300W/12V=25 Amps.
Assuming a 175 amp-hour capacity for two group 24 batteries you could run it for 3.5 hours continuously. But, my 1500W AC electric heater ran for 1 minute every hour when it was around 40F outside with two people and a dog inside a 4'x8' tear.
Bruce

[halfdome, Danny]

300W/12V=25 Amps.
Assuming a 175 amp-hour capacity for two group 24 batteries you could run it for 3.5 hours continuously. But, my 1500W AC electric heater ran for 1 minute every hour when it was around 40F outside with two people and a dog inside a 4'x8' tear.
Bruce

Bruce, Did you take into account that they are hooked to a charging 1.25 amp Battery Tender Plus? I don't really know if it would take longer to replenish power used at the same time it is charging and we would eventually drain the batteries. We watch TV and it seems to go right back up in volts in no time but that's only for a couple of hours of viewing at the most. Danny

[angib]

Bruce,

That looks like a neat little pump - small but with enough capacity for this job. My only query is over the 140degF temperature limit as some water heaters will go past this - my house system goes to 150 degF, though the hot water is then close to scalding.

I keep meaning to draw out a piping schematic as I think this system needs quite bit of kit. This is assuming that the water heater is also used to supply hot water - and it seems a bit silly not to use it for that as well!

Pat,

I did think about floor heating but it seemed to me that with the mattress covering all of the floor, there would be nearly as much insulation between the coils and the 'room' as between the coils and the outside.

Andrew

[halfdome, Danny]

Pat,

I did think about floor heating but it seemed to me that with the mattress covering all of the floor, there would be nearly as much insulation between the coils and the 'room' as between the coils and the outside.

Andrew

How about the walls then? Danny

[bdosborn]

300W/12V=25 Amps.
Assuming a 175 amp-hour capacity for two group 24 batteries you could run it for 3.5 hours continuously. But, my 1500W AC electric heater ran for 1 minute every hour when it was around 40F outside with two people and a dog inside a 4'x8' tear.
Bruce

Bruce, Did you take into account that they are hooked to a charging 1.25 amp Battery Tender Plus? I don't really know if it would take longer to replenish power used at the same time it is charging and we would eventually drain the batteries. We watch TV and it seems to go right back up in volts in no time but that's only for a couple of hours of viewing at the most. Danny

Nope, didn't include the battery tender.
25A-1.25A=23.75 so it doesn't help much. Lets assume the heater runs about 30 minutes when you first turn it in on and 5 minutes every hour for 8 hours. That's a little over an hour of total use (assuming you don't open the doors a lot and your tear is insulated) so you'd only be using about a third of your battery capacity. The only issue then would be charging up the battery the next day. I think it will take several days to charge your batteries after one nights use of the heater with the battery charger you have.

If you have your battery charger plugged in why not plug in a milkhouse heater and then you don't have to worry about the batteries?

Bruce

[bdosborn]

Bruce,

That looks like a neat little pump - small but with enough capacity for this job. My only query is over the 140degF temperature limit as some water heaters will go past this - my house system goes to 150 degF, though the hot water is then close to scalding.

I keep meaning to draw out a piping schematic as I think this system needs quite bit of kit. This is assuming that the water heater is also used to supply hot water - and it seems a bit silly not to use it for that as well!

Yeah I saw the temperature rating too. I'll have to fiddle with the heater thermostat to make sure it doesn't get too hot.

What does "needs a lot of kit" mean? That's not one of those "down the gurgler" kind of phrases is it?
Bruce

[Guy]

Dear Andrew and Bruce,

Here is a site I have used before. Go to "systems" and they will have plans and all the tech info on the questions you have posed.

http://www.radiantec.com/index.htm