Simplified Experiment and Analysis of the Heat Driven Zeolite Heat Pump

Future space missions will encounter a range of challenging thermal environments. The extended missions require a new generation of heat pump technologies. Zeolite/vapor heat pump technology (1) utilizing a condensing/evaporating refrigerant holds considerable promise for space applications due to the variable temperature and variable load capabilities of these systems. Zeolite heat pump systems involve no moving parts and could be made lightweight. To understand the performance of the zeolite/vapor heat pump, a bench scale zeolite/vapor heat pump test stand was built at the Johnson Space Center. The core of the test stand is a 0.12 meter in diameter by 0.33 meter long adsorption/desorption heat exchanger bed, which was loaded with one pound of zeolite beads along with a heat transfer material, Duocell. The test bed was designed for evaluating heat transfer performance for one pound of zeolite with a given heat source of 100 watts applied to the water in the evaporator. This paper will discuss the design and construction details of the test bed, as well as the test results. A math model for predicting the heat transfer of the adsorption/desorption bed has been developed in parallel with testing of the zeolite/vapor heat pump test stand. The mathematical model of the adsorption process in the system will be discussed. Comparison between test data and the thermal modeling results will be presented.