Development of a Small-Capacity Adsorption System for Heating and Cooling Applications

This paper describes the prototype of a small adsorption heat pump working on the adsorption pair silica gel-water. The developed system consists of two modules, each containing an adsorption reactor and a second heat exchanger for evaporation and condensation of the working fluid. The two modules are operated periodically in order to obtain a quasi-continuous heating or cooling output. A reliable control unit has been developed and implemented in the machine. Hot water provided at temperatures of 80°C to 95°C is used to drive the machine, and heat from the low-temperature heat source (10°C to 20°C) is upgraded to the intermediate temperature level of about 35°C to 45°C, which is suitable for low-temperature heating systems such as wall or floor heating installations. For cooling applications, chilled water of 10°C to 15°C is produced in an almost continuous mode. The first prototypes have been tested. Heating coefficients of performance (COPs) of more than 1.3 and cooling COPs for air-conditioning purposes (12°C to 15°C) of 0.5 have been achieved. The machine provided a mean heating power of up to 15 kW and a cooling power of up to 8 kW.