The design of a low cost ventilation air heat exchanger which utilizes plastic sheets as the heat transfer surface is presented. Laboratory tests on such acounter flow heat exchanger have demonstrated very high values of overall heat transfer coefficients, heat exchanger effectiveness, and temperature recovery when the flow is laminar and buoyancy effects assist the heat transfer. The costs of such heat exchangers would make them attractive for many building applications.
A study was made of one hundred subjects who were exposed to air flow with a turbulence as occuring in typically ventilated spaces. Turbulent air flow is seen as more uncomfortable than laminar flow. Each subject participated in three experiments at air temperatures of 20, 23, and 26 degrees C, withvarying air velocity and turbulence intensity. Recommends a reduction of velocity limits specified in existing standards.
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