Evaluation of an air-to-air heat exchanger.

Tests a room-size, residential air-to-air heat exchanger for effectiveness of heat recovery. Conducts experiments in a small wood frame building, the Test Chamber, on the roof of the lab building. Determines heat recovery efficiency by comparing actual heat loss to that expected due to mechanically induced ventilation. The heat exchanger recovers almost 50% of the heat contained in the outgoing air flow. Additional experiments quantify effects of fan power consumption and heat conduction through the case of the device. Concludes that the heat exchanger itself works at an efficiency less than the manufacturers claim.