Is there a source in the US for efficient air to air counterflow heat exchangers? We can't easily use the "magic box" energy appliances developed for Passive House homes in Europe in the US market because of power differences, support, etc. Can we buy just the core counterflow heat exchanger? I could probably gut a US market HRV to get one, but I don't want the fans and I have been led to believe that the German market counterflow heat exchangers are more effective than the cross flow heat exchangers used widely in the US market. Thanks!

This looks interesting - anyone have any experience with this company's products? http://www.klingenburg-usa.com/en/products/cf-advantages.html

That looks great. How complicated would the plumbing be on this ?

I have been looking at Mitsubishi system that should also be available in the U.S. as a fully operational system to suit U.S. voltages.  It is still a cross flow but I think the efficiency is somewhat similar to the one you have shown.  If anybody has any first hand experience with these I would be interested in hearing their comments before I go ahead with a purchase. 

http://www.mitsubishielectric.com.au/2154.htm

The heat exchanger element is replaceable and has the advantage over the aluminium type that it also provides some humidity control as well.  May not be a factor in your location but is for me. 

If you search for Lossnay on the US Mitsubishi site you should be able to find it.

Regards Stephen from Australia

 

This is the residential forum and these systems are designed for commercial applications. I have yet to see a highly efficient residential system and never seen one with the counter flow. Maybe I can just get the core and make a box to put it in, add some fans,controls,dampers, and then you have a standard HRV or ERV. Until the last few years good residential models weren't even available and then the ones on the market today are not near to 90% efficient. The best one I have found is the Fantech ERV or HRV, not because of the efficiency rating, it isn't that efficient.

http://www.fantech.net/hrv_erv.htm
http://www.fantech.net/controls1.pdf

What does make the system efficient is the user friendly controls, 3 fan speeds, overrides, dehumidifaction override, timer that allows for setting of 15on/45off, 20on/40off, 30on/30off, You can add up to 3 boost switches, exterior dehumidistat, and some units actually have a recirculating mode that allows you to take air in from one location within the house and circulate it throughout. What I have found, is that by making it user friendly the homeowner has greater control over the indoor air quality. We have even gone back in after on HVAC guy installed a different HRV unit that didn't even have a timer switch and replaced this 2 year old unit with one of these. HRV or ERV is the question and this is reliant on where you live. Here in the cold Northeastern US I use an HRV, but if I were in a more humid climate the ERV would be the choice. What I have found is that using an ERV as suggested by other professionals is not the right choice when you have a very tight house, especially if it's an ICF house. The ERV units don't allow you to expel the moisture from within the building and in one case neccesitated the use of a dehumidiifier to control the moisture levels, not great for an energy efficient house. Even through HRV units are not designed to control humidity they can and do work for this purpose. If the exterior air is dryer than the indoor air then the unit will bring dry air into the building and expel the moisture. But if it is extremely humid then the opposite is true and the unit brings moisture into the building. Here is the thing, when it is extremely humid in this region we don't ussually have need of this unit running. Like currently, the wheather has been extremely lousy here in NE with more rain in June than I have ever seen and temps way below normal. So even here in late june with daytime highs in the 60-70's we typically have the windows open and the unit is shut off. I tell my customers to only run the unit, when all of the windows are shut. If you have a window or two open shut the unit off entirely and let mother nature do it's thing.

Tom Pittsley
[email protected]
www.eebt.org

The Lossnay core technology has been available in residential units in the US for over 25 years, currently under the RenewAire brand.  The units are single speed, using @ 1 watt per cfm and less than 1 watt of standby power consumption. 

RenewAire only produces ERVs, which have been successfully used, primarily in northern tier states, a geographical area many manufacturer's claim to be HRV acceptable only.  Always read and follow each manufacturer's recommendations for their product.  (An HRV manual may also tell you to turn off the unit in summer.)  I use my EV200 year round (when the windows are closed), and this unit can be used in ME, FL, CA or WI.  

A properly sized RenewAire ERV can reduce excessive humidity from a tightly built house (in winter).  All of my installations have done this successfully in WI.  It can maintain a higher ventilation rate, with better sensible recovery than similarly sized units, while not overdrying, when properly run.  Always compare HVI certified products, and efficiency ratings at similar airflows, not orientation of airflow.  Some brands use counterflow, others cross flow based on their design.

Just like some auto manufacturer's do not recommend E85 fuel for any of their models, and others do for selected models; so air exhangers differ by manufacturer, and within their own product lineup.