REVIEW ON HEAT AND MASS TRANSFER ENHANCEMENT OF THERMOCHEMICAL HEATING PIPE SYSTEMS

The high energy demand to accommodate heating and cooling in building has put tremendous pressure on research to develop more ‘greener’ heating and cooling systems. The conventional vapour compression systems became desirable for new and existing buildings for heating and cooling application due to the fact that the system is well developed and commercially available. However, these conventional systems consume high energy and considered not environmentally friendly with the usage of hydrofluorocarbons as refrigerants. Thermochemical adsorption heat pump is thought to be an alternative solution. However, some limitations such as low thermal conductivity in the adsorbent bed is one of the problems that this new system would face in competing with the conventional heating and cooling systems. Thus, this review would emphasize on various techniques investigated by many researchers on solving low thermal conductivity and the various methods on enhancing heat and mass transfer in the adsorbed bed/pipe. Common techniques used to enhance heat and mass transfer in the adsorbed bed/pipe include introduction of fin type adsorbent tube/ heat exchanger, amalgamated adsorbent bed with metal foam, consolidated adsorbent, adsorbent coating and adsorbent with multi cooling tubes. However, hitherto, the reviewed concluded that the embedding of the adsorbent material into the heat exchanger might be the most promising method which would attain better cooling power.