If you live in a cooling dominated or less than 4000 HDD climate - you might skip this article. Else - in the world of heat/energy recovery mechanical ventilation there exists this nemesis known as dew-point temperature..... and when this is associated with really cold outside conditions - this results in frost accumulation on a heat (energy) exchanger core. You have warm moist air from inside the building exposed to a very cold surface. There is no magic here- condensation at best, and frost at worst is going to happen. Basically- the manufacturer must ensure that the core is not exposed to conditions that will result in frost accumulation on the core. Every manufacturer has slightly different strategies based on the design of the core. The UltimateAir RecoupAerator’s core is a random matrix fiber - and as designed does not start to frost until outside temperature drop below 12 F. That is assuming that inside relative humidity at around 70 F is at or above 25%RH.... inside relative humidity plays a big role in whether or not frost occurs.
The most common defrost strategy employed by manufacturers is known as ‘recirculation defrost’. This strategy temporarily allows the leaving air to be redirected into the incoming air duct to warm it up enough to keep the core from frosting. This cylce is generally 25-75% of an hour, every hour depending on outside temperature. NOTE- that while this is happening - there is no (or very little) fresh outside air coming in. This effectively lowers your fresh air ventilation rate... and turns your mechanical ventilator into a recirculation fan pushing air around for little reason.
UltimateAir has provided a pre-heat - pulse modulated solution that allows for no decrease in ventilation. This is the most efficient solution which ensures the fresh air required for the health of the occupants in the home. This is one of many other methods that best keep the incoming air at or above 12 F.
That is the short of it. Defrost is a fairly complex notion to discuss with regard to the cost associated with it. Know that UltimateAir has your health in mind first.
Contact UltimateAir for more details.
The most common defrost strategy employed by manufacturers is known as ‘recirculation defrost’. This strategy temporarily allows the leaving air to be redirected into the incoming air duct to warm it up enough to keep the core from frosting. This cylce is generally 25-75% of an hour, every hour depending on outside temperature. NOTE- that while this is happening - there is no (or very little) fresh outside air coming in. This effectively lowers your fresh air ventilation rate... and turns your mechanical ventilator into a recirculation fan pushing air around for little reason.
UltimateAir has provided a pre-heat - pulse modulated solution that allows for no decrease in ventilation. This is the most efficient solution which ensures the fresh air required for the health of the occupants in the home. This is one of many other methods that best keep the incoming air at or above 12 F.
That is the short of it. Defrost is a fairly complex notion to discuss with regard to the cost associated with it. Know that UltimateAir has your health in mind first.
Contact UltimateAir for more details.
