Hey guys, I am the guy behind the OpenERV company, who designed the TW4 and WM12 ERV units.
I'm sorry I don't have a bunch of units ready to ship out, as the site says it's still in beta, I am to be honest kind of taking my time because I have another project, the big quiet fan, which is actually funded a little better, and thus I've been directing most of my time to that. But I do advance this a bit most days. I have a twitter where I tweet my progress : @open_erv, and also I'm on bluesky.
I have shipped a few units to other engineers who have/will test the units so I can share third party confirmation for any skeptics.
To clarify some of the discussion, it is not a counterflow heat exhanger, it is a regenerative type. https://en.wikipedia.org/wiki/Regenerative_heat_exchanger. I prefer this type because they can recover latent heat more effectively than recouperative (such as counterflow) type, and latent heat is 40-50% of the total energy content of the air, seasonal average in Ottawa or Toronto.
I am hoping to get the machine tested by the PassiveHaus institute to show beyond doubt how good the efficiency is with a third party test. I have no doubt, I have tested it myself, though.
These can theoretically handy any temperature differential, but the TW4 and WM12 are currently made of a polymer that I wouldn't trust in an extremely hot climate combined with direct sunlight. For that reason, I am focussed on cold climate scenarios. I am pretty sure it will not frost up even in extremely cold weather like -30. I used it last year in my window and had no problem, and it did get to like -25 at least iirc.
I'm sorry I don't have a bunch of units ready to ship out, as the site says it's still in beta, I am to be honest kind of taking my time because I have another project, the big quiet fan, which is actually funded a little better, and thus I've been directing most of my time to that. But I do advance this a bit most days. I have a twitter where I tweet my progress : @open_erv, and also I'm on bluesky.
I have shipped a few units to other engineers who have/will test the units so I can share third party confirmation for any skeptics.
To clarify some of the discussion, it is not a counterflow heat exhanger, it is a regenerative type. https://en.wikipedia.org/wiki/Regenerative_heat_exchanger. I prefer this type because they can recover latent heat more effectively than recouperative (such as counterflow) type, and latent heat is 40-50% of the total energy content of the air, seasonal average in Ottawa or Toronto.
I am hoping to get the machine tested by the PassiveHaus institute to show beyond doubt how good the efficiency is with a third party test. I have no doubt, I have tested it myself, though.
These can theoretically handy any temperature differential, but the TW4 and WM12 are currently made of a polymer that I wouldn't trust in an extremely hot climate combined with direct sunlight. For that reason, I am focussed on cold climate scenarios. I am pretty sure it will not frost up even in extremely cold weather like -30. I used it last year in my window and had no problem, and it did get to like -25 at least iirc.