Performance of two-step thermoelectric-adsorption heat pump for harsh environment electronics cooling

Performance of a two-stage thermoelectric adsorption heat pump for electronics cooling in a thermally harsh environment has been presented. Adsorption heat pumps have few moving parts, which make them suitable for use in harsh environments that are prone to mechanical shock and high temperatures. Use of a thermoelectric device for heat regeneration during the adsorption-desorption process promises to make the system compact enough for electronic enclosures. Two-step adsorption aims to reduce the thermal variations at the hot and cold faces of the thermoelectric device, thus enhancing its performance. Here, adsorption takes place at two different pressures and this requires two evaporators at two different temperatures. This is unlike most `conventional' adsorption systems where adsorption takes place at a single evaporator pressure. An experimental setup (for two-step adsorption) was fabricated and tested for a heat rejection temperature of 185°C and cooling load of up to 6 W. Experiments were also carried out for a single step (conventional) adsorption cycle for similar conditions. This allowed comparing the performance of two-step `modified' adsorption cycle vis-à-vis single step `conventional' adsorption cycle. COPs of 0.2 and 0.3 were observed for conventional and modified cycles respectively.