Energy recovery is trending and rightly so, but there are some important factors to consider that are still being forgotten.
In HVAC the kW load demand required for fresh air purification is quickly outgrowing the energy required due to building thermal transmission.
As building materials and design have improved, it has reduced thermal losses. But our acute awareness and regulatory requirements for fresh air (air changes per hour) has increased.
While in the past fresh air treatment might have only required 20 per cent of total demand, today this can reach in excess of 70 per cent. Clearly saving energy for fresh air treatment must be applied.
As we introduce fresh air we must expel stale air. This exhaust air is poor in terms of quality but rich in terms of energy as it has already been heated or cooled to room temperature. Recovering the energy from this exhaust air is the target.
Many other companies have also understood this requirement and Air Handling Units (AHUs) are frequently equipped with Enthalpy Wheels.
But there is a design flaw, they recover energy between fresh air and exhaust air directly. This method works well in high or low ambient temperature because the temperature between the two are high but extreme weather only occurs one to three per cent of the time. What about the other 97 per cent.
Thermodynamic Energy Recovery (THOR) is different. This is why.
Cooling in packaged air conditioning systems is done via the refrigeration cycle where a compressor compressors gas and condenses the gas to liquid (hot side is typically 50oC) and then expands the same gas (cold side is typically 7oC). The compressor uses the most energy in this process and more than the ventilation fans.
THOR uses the exhaust air over the refrigeration condenser (in cooling mode) and reduces the hot side from the typical 50oC to approximately 35oC. In doing this the compressor uses less power. This effect is irrespective of ambient temperature and as such THOR has high efficiency in more climatic conditions.