Magnesium oxide/water chemical heat pump to enhance energy utilization of a cogeneration system

A chemical heat pump using a magnesium oxide/water reaction system is expected to be applicable to cogeneration systems using gas engine, diesel engine, and fuel cells. The operability of the heat pump was examined experimentally under hydration operation pressures between 30 and 203 kPa. In the experiment, a reactant having high durability for repetitive operation was packed in a cylindrical reactor. The cycle of operation was repeated under various thermally driven operation conditions. The forward and reverse reactions were studied by measuring the reactor bed temperature distribution and the reacted fraction changes. The reactor bed stored heat at around 300-400 degrees C by the dehydration reaction and released heat at around 100-200 degrees C by the hydration reaction under the heat amplification mode operation. The practical possibility of the reactor bed was discussed based on the experimental results. The heat pump is expected to be applicable for load leveling in a cogeneration system by chemically storing surplus heat during low heat demand and supplying heat during peak demand. It was shown that the chemical heat pump would be able to improve the efficiency of energy utilization in cogeneration systems while also helping to reduce energy consumption and global carbon dioxide emissions. (c) 2004 Elsevier Ltd. All rights reserved.