Abstract
Representative reversible endothermic chemical reactions (paraldehyde depolymerization and 2-proponal dehydrogenation) are theoretically assessed for their use in a chemical heat pump design for compact thermal management applications. Equilibrium and dynamic simulations are undertaken to explore the operation of the heat pump which upgrades waste heat from near room temperature by approximately 20 degrees in a minimized system volume. A model is developed based on system mass and energy balances coupled with kinetic equations to ascertain mixture conditions at each state point in the loop, as well as mass flow rate, minimum work input, and minimum endothermic reactor volume according to defined reservoir temperatures and desired heat load. Assuming that a pervaporation process is employed in both reaction systems to achieve the requisite mixture compositions for sustained operation, the simulations show that the chemical heat pump can pump 5Wof power with endothermic reactor volumes of as little as 60–93 cm3, depending on the selected chemical reaction. Low exergy efficiencies remain a significant design consequence, but the system performance in terms of environmental impact and COP are comparable with, and in some cases better than, the performance of alternative technologies under the same conditions.
Keywords
Miniature chemical heat pump, thermal management, energy conversion, paraldehyde depolymerization, 2-propanol dehydrogenation
Date of this Version
2012
DOI
http://dx.doi.org/10.1016/j.enconman.2012.04.015
Published in:
S. Flueckiger, Z. Yang and S. V. Garimella, “Thermomechanical Simulation of the Solar One Thermocline Storage Tank,” ASME Journal of Solar Energy Engineering, Vol. 134, 041014, 2012.