Plate Heat Exchanger Adsorber for a Regenerative Adsorption Heat Pump

The state of the art in regenerative adsorption (solid-vapor) heat pumps achieved to date is a maximum Coefficient of Performance for Cooling (COPC) of 1.1 with 70% regeneration of waste heat. A number of configurations for the heat exchanger within the adsorbent bed have been investigated, including concentric tube, shell and tube, serpentine flat pipe, spiral flat pipe, and single-pass plate type. However, to date, compact (or multiple pass plate) heat exchangers for use with adsorbent beds have not been studied. This investigation explains the challenges involved in this application, and describes the design and analysis of three configurations of a compact heat exchanger for use with solid adsorbent. The prinicipal figure of merit affecting both coefficient of performance, COPC, and specific cooling power, SCP (W cooling per kg adsorbent), is defined as NTU divided by the ratio of non-adsorbent (“dead”) to adsorbent (“live”) thermal masses. The best of the three configurations consists of thin adsorbent (zeolite) tiles epoxied to the heat exchanger plates (sheets) with screen wire pin fins in the oil passages to enhance heat transfer.