Most efficient HRV/ERV product for small airtight space, all seasons?
Hi, I’m building a mobile office using a heavily-insulated, airtight 20-foot shipping container. All heating/cooling is via a single heat pump powered by batteries and 2000 watts of solar panels on the roof; this will have no windows. It will be used in New England, so cold winters and hot summers.
I wanted to know what the most efficient heat recovery ventilation would be for such a small space, that I can actually buy in the US.
So far the best candidates I’ve found are:
– Zehnder Novus 300 HRV (claims certified 93% efficiency by Passive House Institute) http://zehnderamerica.com/products/heat-and-energy-recovery-ventilation-units/
– TwinFresh Comfo (claims sensible efficiency of 91%, no PHI cert that I can find, but affordable price and smaller footprint, plus it is a 12v DC system so more compatible with my solar than the Zehner which is AC)
http://www.homedepot.com/p/VENTS-US-TwinFresh-Comfo-32-CFM-Power-5-in-Single-Room-Energy-Recovery-Ventilator-TwinFreshRA1502/204785337
Are there any other products that meet or exceed the efficiencies of these? In my situation, would a central HRV like the Zehnder be better, or a pair of the TwinFresh synchronized for intake/outtake? Thanks for the help.
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Replies
Efficiency Dude,
Lunos fans claim a heat recovery efficiency of 90.6%. Note that there are various ways to determine HRV efficiency, so you might want to delve a little deeper into these claims if the efficiency matters to you.
Efficiency Dude,
I hope you have a backup plan for space heat. During the winter in New England, it's easy to get three weeks of cloudy weather. I don't know what kind of battery you think is going to power a heat pump through three cloudy weeks in December.
Certainly, 2 kilowatts of PV on the roof will be close to useless from November 1 to February 10.