Alde Heat Distribution

AnOldUR

On the nuCamp Facebook group there was a post about using a JEGS heater in a T@B. It would not replace the Alde. It would replace the aluminum convectors and change the heat distribution to allow for forced air instead of solely being convection. This sounds interesting to me. I'm considering a variation on this, but was curious of opinions here on the forum.

https://www.amazon.com/gp/product/B07HB9QWHW/ref=ox_sc_saved_title_4?smid=A30XU5Y510T9EB&psc=1

RTWCTS

115W divided by 12V is about a 9A draw per hour. Do you have the battery capacity to support that? Or is this for when you are on shore power? It can work, of course. These are just my initial reactions to the mod.

AnOldUR

@RTWCTS Most of our time is spent dry camping, so draw on the battery is a concern. The JEGS has a three speed motor with the lowest setting drawing about half that amperage (still fairly high). With the small size of a 320 cabin, the low speed should be all that's needed. Also, it would not have to run continuously. A thermostat in the glycol line might work.

Actually, looking at that Facebook post had me thinking of a similar concept instead of the JEGS. I've always thought that the convectors under the bed were not very efficient. Not enough of the heat makes it into the cabin. My thought was to eliminate them and only use the convectors under the bench seat. To increase their effectiveness, I'd add a booster fan to the wood panel below the seat. This fan draws less than 2 amps on high and could be set to only run when heat from the Alde is present. My guess is that the forced air would heat the trailer faster than convection.

Grumpy_G

One of the features of the Alde system is the fairly quiet operation, adding fans will increase the noise level, pretty substantially in case of the Jegs heater (Jegs sells parts for performance cars+trucks where noise is not a major concern). 
The other potential issue is that the Alde system does not generate that much heat compared to a vehicle engine or a home furnace (which is why it takes so long to heat the cabin from low temps). That doesn't change when finding new ways to transfer the heat into the cabin. 

Mickerly

With our 320CS the biggest problem is both convectors are covered when the bed is made. I built an extension to the aft vent allowing the heat to get above the mattress. That helped a lot. Then I covered the open areas around the convector box in underseat cabinet with cardboard taped in place. That helped more. Now, it heats reasonable fast and is responsive to changing the thermostat.

I thought about putting a fan under the bed, but I like the silent heat. Add a light rain on the aluminum top and I get amazing sleep.

If you don't mind the fan noise, it looks like a good idea.

fstop32

I placed a 3" x 3" three speed computer fan at floor level and modified the center bench support to be a duct so I could pick up cooler air at floor level and gently push it toward the back and up through the large convector.  At low and medium speed you can't hear the fan at all.  The idea has worked well, still quiet with just a bit of "forced air" movement.

Basil48192

For those considering either of the blower options above, be sure to check the glycol pressure drop across the new coil(s) as compared to the original design.  I have no idea how much pressure the Alde pump can generate, but it's worth looking into before making a change.  

AnOldUR

Basil48192 said:

... I have no idea how much pressure the Alde pump can generate, but it's worth looking into before making a change.  

I hadn't thought about that. The open expansion tank means this is not a sealed system, but the pump does create pressure in the system that could be restricted by the flow through the JEGS core. Definitely something to consider.

I'm going to try the booster fan method rather than the JEGS. Since it will use the existing convectors under the passengers side bench seat, there should not be any change in flow rates.

The booster fan came late yesterday and I got a chance to test it out this morning. At the highest fan speed it's pretty loud, but the lower speeds are not bad. The lowest speed draws less than .1 amps, while the boost setting pulls 1.6 amps. My guess is that I will never need to use over the "4" setting that draws a little over .2 amps. Since the fan will cycle on and off, running down my LiFePO4's should not be a problem. These number are through a 120V to 12V power supply. There may be some inefficiency there. When tied directly to the T@B's 12V system power consumption may be a little different. It will be interesting to see how the heat distribution works. Will the highest speed pull too much air past the convectors and be counter productive?

Tabaz

A few years ago I extended the Alde loop into the area under the floor to keep the tanks warm in winter.  Five mini-convectors were added in the extended loop under the floor.  The existing pump worked fine with the added piping.  In fact, I kept the pump setting at 2.5.

AnOldUR

Sunday project. Finished the fan install. I ran the Alde on electric and the fan seems to distribute the heat well. Hard to be certain with the trailer in the garage. The thermostat does a good job of turning on the fan when the Alde is supplying heat to the convector and turning off when they cool down. We're due to replace the Rhomar this winter. I'll remove the convectors under the bed at that time. Thinking about how to use the space gained for storage.

We're heading to Upstate New York on the 14th, so it'll get a better test then. Lows will be close to freezing.

ybakos

@Mickerly Sounds super interesting, could you share a couple photos, please?

AnOldUR

Home from that five night Finger Lake vineyard/brewery tour. Temps had water in dogs bowl frozen in the morning. No hookups at any of the five Harvest Host sites. The blower made a big difference in the speed and dispersing of the Alde heat. Also the air movement kept the condensation to a minimum. This may make the top of the list of the many mods done to our 320.

The only down side is that there in no differential in the thermostat setting. When the set temperature and duct temperature were close it would repeatedly cycle on and off until there was enough of a difference in the two. If I were to do it again I'd look for a duct fan with at least a few degrees of differential or one that was user settable.

Mickerly

I tend to default to simple first. We needed heat above the bed. So, I extended the vent.

Mickerly

It is a ceda bed slat with two spacers. The cushions hold it in place.

Slackers

I've tried using a USB powered fan under the bed which helps, but isn't nearly as robust or efficient as the ideas listed above.

AnOldUR

Agree @Slackers. I also put a fan under the bed in an attempt to force air up through the back. It worked, but only to a small extent. I was very pleased with how much heat was forced out by the duct fan under the bench seat. Once I remove the rear convectors under the bed and the heat loss there, I suspect it will be even better.