Miniature heat pumps for portable and distributed space conditioning applications

The Pacific Northwest National Laboratory (PNNL) is developing a miniature absorption heat pump for a range of microclimate control applications, including manportable cooling and distributed space conditioning. The miniature absorption heat pump will be sized to provide 350 W cooling, will have dimensions of 9 cm×9 cm×6 cm, and will weigh approximately 0.65 kg. Compared to a macroscale absorption heat pump, this represents reduction in volume by a factor of 60. A complete manportable cooling system including the heat pump, an air-cooled heat exchanger, batteries, and fuel is estimated to weigh between 4 and 5 kg, compared to the 10 kg weight of alternative systems. Size and weight reductions are obtained by developing a device that can simultaneously take advantage of the high heat and mass transfer rates attainable in microscale structures while being large enough to allow electric powered pumping