Modification ideas for boondocking

[Bluebeard]

I've got some ideas and I thought I'd run it by you guys (gals):

First of all I have an 2002 Arctic Fox 24-5N 5er which I plan on exclusively using for boondocking in the high mountain western states. I bought the trailer for a song, and I am not concerned about losing resale value. No hookups- ever- so here are my thoughts:

1. I will NEVER use the rooftop air conditioner. NEVER. And if I were in a location where I needed cooler "conditioning" I would most likely build a 5 gal bucket swamp cooler. So I was thinking of taking off the AC from the roof and putting a vent in there. However, the AC hole in the roof has remote vent lines taking off from the cut out in the roof. So I was thinking, for heating and cooling, to modify the vent fan such that the actual fan was located BELOW the intakes to the vents. If I wanted to spread conditioned air (hot or cold) through out the trailer, I just need to turn on the fan with the vent top closed, and I would assume the air would be spread around the camper. Yes/No?

2. I plan on putting in a Cat heater as the cycling of the forced air fan on the furnace at night keeps me awake. So I was thinking of replacing the stock furnace with a Wave 6 heater mounted pretty much in the same location as where the furnace was. I was thinking of taking out the furnace, and then putting in a low speed (quiet) muffin type fan at the entrance of the heater ducts where the furnace used to be and to have a switch where I could turn on the muffin fan on the really cold nights to circulate (at a low speed) the cabin heat down to the basement.

Is this plausible? Any suggestions for a decent 4' 12v fan that is quiet and moves air?

3. Has anyone ever considered setting up a mini drainback solar hydronic system on the roof to preheat the water for the hot water heater? I would be pretty simple to set up with some black tubing on the roof, and it would run on sunny days. When you came back from hiking, maybe the water in the hot tank would be 120F, so you wouldn't need to fire up the furnace.

Thanks for any insight.

[Rice]

Bluebeard wrote:
I've got some ideas and I thought I'd run it by you guys (gals):

Thank you for including us gals.

Bluebeard wrote:
3. Has anyone ever considered setting up a mini drainback solar hydronic system on the roof to preheat the water for the hot water heater? I would be pretty simple to set up with some black tubing on the roof, and it would run on sunny days. When you came back from hiking, maybe the water in the hot tank would be 120F, so you wouldn't need to fire up the furnace.

I'm not sure if you're trying to get hot water or hot air (or both), but I'm a fan of free hot water and have my eye on this in case we ever quit using our satellite internet dish and free up some unshaded roof space: RV Solar Hot Water Kit

[reed_cundiff]

Some good ideas on thread

We have an Olympian Wave 8 that will keep main cabin of 34' 5th wheel in low 60s when outside is in teens. The Open Range series are inexpensive but have R30 top and bottom and R9 on side. We bought the double pane window option and are happy we did.

We have worried about freezing pipes in basement (main luggage compartment) but we leave on one or two of the 30 W halogen lamps at night and it keeps the basement in mid to high 30s when 10 F outside. We have 9.6 kW of LFP so this is no problem.

The LFP are not supposed to be charged at high C when below freezing so we shall put a small electric heater in the front luggage compartment to keep the temperature above freezing. It is to be noted that we are "Goldilockers" as in "not to hot and not to cold, just right!" However, we still have spent nights down to below 10 F and have to worry about damaging the battery suite.
Reed and Elaine

[toddb]

SteveAE wrote:


Bluebeard,
Just some thoughts for you:
- If you use the same water heater that you have hooked up to your potable water, look for (or build) a radiator that is safe to use with potable water. I would not want to introduce a vehicle radiator into my water system.
- To get higher water temps (necessary to avoid the dreaded "wind chill" effect) you will want to increase the water heaters thermostat temp.
- As mentioned by another poster, you will have to drain the system whenever you want to store your trailer. Yes, you can get around this but using a separate water heater and system filled with a water/alcohol solution, but that adds expense...and also further reduces system efficiency.
- A typical RV water heater is about 12K BTU and has an efficiency of maybe 60% (on propane). Then you have losses in the plumbing...say another 20%. So you maybe get total system efficiency (as far a heat transfer goes) of 40%. Or, 4.8K BTU of heat output for your 12K BTU of energy input. On top of that, you then have to provide electricity to run the pump and fan. Assuming you only use 1 amp per hour, that's still 24 amp hrs per day...or about 12% of a typical golf cart battery. But, since you shouldn't draw a lead acid battery below 50%, this means that you just burned up about 24% of your of the usable power from a single golf cart battery just to run the system for 24 hours. Perhaps this would be acceptable for a mild climate, but in more severe winter climates, it is much more much more efficient to use a 6K BTU Wave heater (maybe 95% efficient so ~5.7K BTU heat out for 6K BTU of energy input) with zero electrical consumption at all. Yes, I do have to open the windows for both ventilation and to eliminate moisture. But gosh, even with an electric heater (for those rare times I have the luxury of plugging in), I still have to provide about the same amount of ventilation to get rid of the moisture that we (2 people and one dog) exhale.

So from my experience, and the temps that I camp in, the simple hydronic system using the domestic water heater just didn't cut it. Now had I had the $$$ to install an Espar diesel heater, then that might have been a different story. Anyway, just trying to save you some work and $$$, but whatever you do, I wish you the best and look forward to hearing your final solution.

The efficiency numbers are sort of moot point. The boiler doesn't need to put out 10K btu, it's not raising 40* water to 140, it's recovering 120* coolant to 140*. For our scale it's fine if it takes 2 extra minutes to recover, and consumes half the propane and less than half the power. On 8 hours of run time and a 50% duty cycle my 6v batteries don't fall below 12.3V, and my solar panel recovers them by noon.

[Bill_Satellite]

You mention that you had no problem keeping the RV at 58 degrees when you camped in 38 degree outside temps. That means you were simply cold and not freezing! Cold, in any form, is not my idea of a comfortable solution. I would need to have some "real" heat to get us from 58 degrees to what I would consider comfortable.

[SteveAE]

Bluebeard wrote:
Todd- I am assuming you are using a different water heater for hot water? Atwood doesn't make a heater for "solar" does it? It would be nice to use the same water heater for both. At my house I have a AO Smith Vertex tank water heater that supplies 4 gpm of 160F water (Something like that)- so it has a tank, runs my hydronic floor loops and I get unlimited hot showers from it. I'd love to have a mini version of that in my rv.

Bluebeard,
Just some thoughts for you:
- If you use the same water heater that you have hooked up to your potable water, look for (or build) a radiator that is safe to use with potable water. I would not want to introduce a vehicle radiator into my water system.
- To get higher water temps (necessary to avoid the dreaded "wind chill" effect) you will want to increase the water heaters thermostat temp.
- As mentioned by another poster, you will have to drain the system whenever you want to store your trailer. Yes, you can get around this but using a separate water heater and system filled with a water/alcohol solution, but that adds expense...and also further reduces system efficiency.
- A typical RV water heater is about 12K BTU and has an efficiency of maybe 60% (on propane). Then you have losses in the plumbing...say another 20%. So you maybe get total system efficiency (as far a heat transfer goes) of 40%. Or, 4.8K BTU of heat output for your 12K BTU of energy input. On top of that, you then have to provide electricity to run the pump and fan. Assuming you only use 1 amp per hour, that's still 24 amp hrs per day...or about 12% of a typical golf cart battery. But, since you shouldn't draw a lead acid battery below 50%, this means that you just burned up about 24% of your of the usable power from a single golf cart battery just to run the system for 24 hours. Perhaps this would be acceptable for a mild climate, but in more severe winter climates, it is much more much more efficient to use a 6K BTU Wave heater (maybe 95% efficient so ~5.7K BTU heat out for 6K BTU of energy input) with zero electrical consumption at all. Yes, I do have to open the windows for both ventilation and to eliminate moisture. But gosh, even with an electric heater (for those rare times I have the luxury of plugging in), I still have to provide about the same amount of ventilation to get rid of the moisture that we (2 people and one dog) exhale.

So from my experience, and the temps that I camp in, the simple hydronic system using the domestic water heater just didn't cut it. Now had I had the $$$ to install an Espar diesel heater, then that might have been a different story. Anyway, just trying to save you some work and $$$, but whatever you do, I wish you the best and look forward to hearing your final solution.

[Jframpey]

Anyone have any experience with these?
Vented oil heaters
I'm a little skiddish about using unvented heaters where I sleep... I'm not sure how the fuel is delivered - on board tank or remote? But they are recommended on some tiny house websites.

[creeper]

Look at the Dickinson boat propane heaters. No threat of suffocating yourself to death. Very efficient and little clearance issues.

[westend]

Todd,
Thanks for the reply. Good information about the shortcomings of using an existing heater and the filtration issues. I had already assumed the heat exchange area would be warmer than areas farther away. But, hey, 58f is a lot better than 30f. The hydronic heating is very intriguing.

[toddb]

Yes, the fan moves the hot air not radiant heat. The radiator was scrap from work, I just had to reweld a crack on it. I would think any truck heater core would suffice. I removed the old heater and shifted things around to get it fit. I use another unit for hot water, I searched for a suburban motor aided water heater since they have a heat exchanger built in but never located one, new they are ~$500 but it would allow one unit to do both jobs.

westend, we've camped to low 30s without any trouble keeping the trailer at 58*. The thermostat isn't ideally positioned so I think it gets a little warmer in the rear of the trailer(26' toyhauler) the way the airflow is directed. The only things I've done are lined the bottom of the trailer with coroplast and the wife made heavy curtains that snap to walls around the windows. My first rev used the water heater with a circulation pump to make a hot water loop, but all the junk from the anode/calcium kept plugging the filter up.

I was going to use a catalytic heater but we camp in northern AZ, generally over 7600' and it's extremely dusty.

[westend]

Todd,
What kind of ambient temperatures have you used your hot water system in and did the system heat the trailer well?

I'm thinking of running a loop off my existing water heater and trying out a similar type of heating system. I'd use it to heat a certain area of my trailer rather than relying on it to heat the whole interior.

[Bluebeard]

Todd- I am assuming you are using a different water heater for hot water? Atwood doesn't make a heater for "solar" does it? It would be nice to use the same water heater for both. At my house I have a AO Smith Vertex tank water heater that supplies 4 gpm of 160F water (Something like that)- so it has a tank, runs my hydronic floor loops and I get unlimited hot showers from it. I'd love to have a mini version of that in my rv.

[Bluebeard]

Todd- so you aren't using an "infloor" hydronics, but a fan blowing through a radiator? THAT would simplify the hydronics immensely. Where did you get the radiator? Can you add the link? That would be really easy to set up and it wouldn't dry out the air like the furnace would OR make it damp inside like burning propane would. Did you take out the furnace and put the radiator there instead? I am assuming your RV is different from mine. Cool idea.

[toddb]

This is the setup. Atwood 6gal water heater, 140* thermostat. Topsflo PV water pump/filter. The radiator is about 8x8x2.5" thick with a 140mm pc case fan that moves a good amount of air. I epoxied a well on the side of the water heater for a thermostatic switch, it closes at 100* and opens at 85* to interlock the pump and fan. I turn on the water heater manually then let the thermostat control the pump and fan via small relay.

It's quiet, doesn't dry out the air and pulls 1.2-1.3A running and the propane consumption is about 35% of the old heater. It'll cycle on for about 25min and off about the same, the water heater usually cycles on during the pump off time or close to it.

[Bluebeard]

n7bsn- you are right about the climate- I misspoke. In my elderly age, sometimes I forget. This area was noticed for its cold climate in the Summertime (and most cold days year-round). It gets cold here, but Cutbank Montana and North Dakota gets a LOT colder in the Wintertime. We still have cold winter nights, but the cold winter DAYS, is where the mid-west wins for sure. My bad.

I am sure my AF isn't dual pane. I must be the "lucky" 5%.

Thanks for clarifying the facts.