(A) study on the thermal characteristics of a double-spiral heat exchanger using a thermo-electric cooler

Abstract

A double spiral heat exchanger used as a novel dehumidifier is proposed and constructed, by merging the merits of the double spiral configuration and the advantages of thermo-electric coolers (TECs). Numerical work to verify previous reports is initially conducted, along with other preliminary experiments related with the heat removal capacity of the TEC. Following the integration of various sub parts into an operating dehumidifying system, further experimentation is conducted to obtain temperature profiles in the dehumidifier for various inlet air temperature and humidity conditions. The formed condensate is removed from the dehumidifier through condensate wicks attached to the bottom plate of the dehumidifier. The amount of condensate is measured using a precision scale. The temperature profiles obtained for dry and moist air inlet conditions show that the heat removed consists of only sensible heat in the case of dry air and both sensible and latent heat for moist air. The sensible heat is calculated using the well-known LMTD heat exchanger analysis. The latent heat is accounted for using the psychrometric chart. The sum of the sensible heat transfer and the latent heat transfer in the double spiral heat exchanger adds up to approximately equal the heat removed through the TEC. The operating dehumidifier yields daily condensate amounts in between 160g and 200g over a 24 hour period for the given inlet moist air conditions.