DEVELOPMENT OF AN OPTIMISED SOLAR DRIVEN DIFFUSION-ABSORPTION COOLING MACHINE

摘要

Currently there are no thermally driven cooling machines available on the market, which could provide smaller cooling capacity for cooling buildings of less than 10 kW. This paper is focused on the development and testing of an optimised single-stage solar heated ammonia-water (NH3-H2O) Diffusion- Absorption Cooling Machine (DACM). The designed cooling capacity of the cooling machine is 2.5 kW at evaporator temperatures between –10 and +5°C with indirect heating through commercial vacuum tube collectors. The indirectly heated, solar powered generator (bubble pump) represents the main new feature of this cooling machine. The first prototype of the DACM was designed, developed and built in the Building Physics laboratories at the University of Applied Sciences Stuttgart, Germany in October 2000 within a European JOULE-CRAFT program. A series of measurements from November 2000 to March 2002 were undertaken for the pilot plant of the DACM. The results show that COP values range from 0.1 to 0.3 and the cooling capacity of the pilot plant could reach 1.5 kW, but the operation stability was insufficient. In order to increase the cooling capacity and the COP, it was found that further optimisation of the internal fluid cycles and reduction of the heat losses were necessary. These findings led to produce a second prototype that was more compact and built in November 2002 using partly standard components such as plate heat exchangers.