Frosting and leakage testing of air-to-air energy recovery systems.

Reports investigation of the limiting conditions that produce frosting on air-to-air heat exchangers. Also determines the adequacy of provisions for the prevention of frosting and ice buildup. Four types of heat exchanger were investigated as part of a more general investigation of the operating characteristics of air-to-air heat exchangers. Also reports investigation for various types of energy recovery systems of the cross leakage or contamination of the fresh air by the exhaust air.