EXPERIMENTAL-STUDY OF HEAT-TRANSFER CHARACTERISTICS OF MAT-TYPE ADSORPTION HEAT-PUMP

A silica gel-tube module (ST-module) was provided as a heat exchanger for an adsorption heat pump (AHP). A multiple adsorbent-tube (MAT) type adsorber containing the ST-modules was proposed and applied to the AHP for the silica gel/water vapor system. Heat transfer characteristics in the AHP with the MAT - type adsorber were studied on the basis of the results compared with those in the AHP with a packed bed type adsorber. Both the maximum temperature rise in the evaporator and the times required to reach the initial temperatures in the adsorption and desorption processes for the AHP with the MAT-type adsorber were reduced to about one-tenth of those for the AHP with the packed bed type adsorber. In the evaporator of this AHP, cold heat below 280 K was obtained at the adsorption process. Based on pressure profiles of water vapor in the adsorption process, it was found that the pressure difference between the adsorber and the evaporator contributed to pumping-up of the heat in the AHP. Therefore, enhancement of heat transfer in the adsorber of the AHP was achieved and the possibility of its application to an airconditioner for producing cold heat energy was suggested.