Efficient adsorption refrigerators integrated with heat pipes

Abstract

Several novel ideas to use heat pipes in adsorption water chiller or ice maker are presented in this paper. Experimental results have shown that the adsorption refrigerators are very efficient. The first example of such systems is a small scale silica gel–water adsorption water chiller with cooling power rated as 10 kW; the system could be powered by 60–100 °C hot water, a cooling COP = 0.4 has been achieved when driven by 85 °C hot water. This adsorption chiller has been used for solar powered air conditioner and also as the chiller for CCHP system. The second example is a silica gel–water adsorption room air conditioner powered by 80 °C hot water. The system is very compact and is suggested for potential applications of micro CCHP system based on fuel cells. The system has a COP of over 0.3 and cooling power of about 1 kW. The third example is the use of split heat pipes to heat or cool the adsorber for making ice in fishing boats. The application of these technologies avoids the corrosion of adsorber at the heating phase by exhausted gases and at the cooling phase by seawater, and also has the advantage of high heat transfer performance. With such arrangement and careful considerations of the arrangement of wicks in heat pipes, and also the use of composite adsorbent (calcium chloride and activated carbon)-ammonia adsorption pair, the system test has shown the specific refrigeration power for more than 730 W/kg at −15 °C.