Design, fabrication, and experimental demonstration of a microscale monolithic modular absorption heat pump

The first ever conceptualization, design, fabrication and successful experimental demonstration of a thermally activated microscale absorption heat pump for miniaturized or mobile applications is reported here. Several-fold enhancements in coupled heat and mass transfer possible in microscale passages remove significant hurdles that have hindered the implementation of thermally activated heat pumps. Cooling capacities of 100 W–10 s of kW are possible through minor changes in component geometry. These mass-producible miniaturized systems can be packaged as monolithic full-system packages or as discrete, distributed hydronically coupled components integrated into buildings. A 300 W nominal cooling capacity ammonia–water absorption heat pump with overall dimensions of 200 × 200 × 34 mm and a mass of 7 kg was fabricated and tested over a range of heat sink temperatures from 20 to 35 °C with 500–800 W of desorber heat input to yield cooling duties of 136–300 W.

► First ever demonstration of a thermally activated microscale monolith absorption heat pump. ► Microscale heat and mass transfer and component integration enables miniaturization. ► Cooling of 300 W achieved with 200 × 200 × 34 mm, 7 kg unit. ► Modular: large capacity range possible through minor changes in component geometry.