Heat Recovery Ventilators

calameda

Member
Anyway, i decided i’m building my own HRV with filters, a very high efficiency insulated aluminum core that is washable, PWM adjustable speed high efficiency fans with DC brushless motors w/sound deadening material, in a package that is suitable for van (or RV) life.

Sounds ideal! any interest in building more? Then sell your business to Dometic? :)
 

TAOspinner

New member
There are more issues with these:
1. inlet and outlet air are in the same location
2. the core becomes contaminated over time.
3. dehumidifying is based on the % of moisture in the intake ( see reason 1 ) air.


Best is a dehumidifier and/or cold air inlet to the furnace or to a hydronic air handler View attachment 816162 and an open vent/window to discharge moist air.
Adding an outside vent to the heater is the cheapest option but it actually is no better that opening a window as far as efficiency goes because now the heater is having to heat that cold air instead of the cabin air requiring much more energy to do so.
 
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TAOspinner

New member
Sounds ideal! any interest in building more? Then sell your business to Dometic? :)
After testing the one i build, I’d definitively consider building more. I’ll need to create special vent covers for the fresh and exhaust. Anyone desire to help with this? 🙂
A 3D printed model would be great to start with…
 

TAOspinner

New member
So I did a bit more digging into the Lunas eGO as well as the E2 units.
And again, HRV units have their place, but you have to decide whether or not it is justified for your use case.

For those interested in these... there are a couple of items Id suggest you look into further
There doesnt look to be sufficient data for both the E2 and the eGO, so data looks to overlap... YMMV
But extreme cold operation and noise are two concerns of mine, besides what Ive already expressed in the thread so far.


For extreme cold... this seems like a legit issue. 35% ? Thats awfully low.

53475813156_22c9b5072a_b.jpg



Which seems contrary to this claim with regards to frosting, claiming testing and operation down to -32 without "active prost protection"
53474919137_5ee810ca4d_o.jpg




And finally, specific to the eGO, the noise issue. Looks like up to 38dB, which would definitely bother me....
especially when you factor in the oscillation. The fans cycle back and forth.... constantly

53476129914_0e36aa13e7_b.jpg

Yes, because the unit is not insulated from the outside air, humid cabin air will more easily condense and freeze near the outer portion of the inlet. Also, the fan is on the inside of the core which creates a lower pressure on the inlet side further reducing the air’s temperature.
Another problem with these single source units is that during the outflow a low pressure condition is created within the cabin. There is no way around it that air will infiltrate through small cracks in the air barrier of the cabin thereby negating the purpose.
 

Alloy

Well-known member
Adding an outside vent to the heater is the cheapest option but it actually is no better that opening a window as far as efficiency goes because now the heater is having to heat that cold air instead of the cabin air requiring much more energy to do so.
Adding and an outside vent to the heater is better because the wasted heat if the exhaust can be used the heat the incoming air.

This is a concentric vent I made.

20171127_125615.jpg
 

Seaweed

New member
Interesting thread, we have Lunos HRV units in our house in VT. It isn’t completely passive/net zero but close and they are awesome keeping the air quality high in the winter. We turn them off for the summer when we start opening windows.
 

kurad

New member

I bookmarked these a while ago when I saw the price of the Lunos devices. You can't really compete with a ceramic core but looks like a fun project and quite doable.
 

Alloy

Well-known member

I bookmarked these a while ago when I saw the price of the Lunos devices. You can't really compete with a ceramic core but looks like a fun project and quite doable.

Anyone thinking of these should read posts #54 and #59
 

montaillou

New member
Thread is not too old...
I've been working on an expedition mini home build for a few years now. I want to use a C ERV because I plan on making the living area fairly air tight and am worried about co2 build-up. I have read the posts about "just leaving a window cracked at -20" and I suppose if you like it brisk this works for you. However, my heat will come from a wood/coal stove that I will bank when I sleep. The stove draws from the outside, so that's not an issue, but the coals will die out before I wake and leaving a window cracked will mean waking up in the cold which I would prefer not to do. While not fatal, I would just prefer to preserve heat/cold when possible. Also, the outside air quality might not always be great and some ERV's come with filtration units. Again, there could be a work around, but why not just get something that will do it all if you can afford it? I intend to live 24/7 in this space for at least 2 - 10 years (engine gods willing). I have a full shower that I will sparingly use, but there will be some steam. Also a small space gets humid fast when you track snow/water inside.

Power is a consideration as I have a solar powered battery bank (24v) powered by 8 panels. While I believe my energy supply is sufficient, I don't want to waste power if I don't need to. Fuel is the one resource I can't replace easily and will only be used to move the truck. My a/c (Red Dot) is battery powered. I have tried to accumulate energy efficient appliances, but there are some things that just don't work that way.

Does anyone have experience with either the Mini or Climate from Accurasee? My living area is a little under 100 sq/ft & the ceiling is just over 6', and though the Climate is overkill the literature suggests it uses less electricity compared to the Mini. I am looking at wall mounted units as my solar panels use up the roof. I have also looked at the Pioneer Ecoasis150 which has purports to monitor the air for co2 build-up. However, the Pioneer does look like it uses more electricity than the Accurasee. My walls are approximately 3" thick.
 

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