DEVELOPMENT OF A 50 KW ABSORPTION CHILLER

摘要

A research project with participation of an energy provider (Vattenfall Europe), who operates large district heating systems, was set up with the aim of developing high efficient absorption chillers in the range of 50 - 320 kW. A cost effective system set up for the entire cooling generation including reject heat, hydraulic components and control is headed for. In a first step a 50 kW absorption system was developed, tested, and is already running in a demonstration plant since late 2010. At the same time, the development of bigger systems is ongoing. The project is supported by the Federal Ministry of Economics and Technology represented by Project Management Julich (PTJ). The chiller operates in between 25% and 140% load at a thermal COP in the range of 0.8 and can be turned down to a part load of 5%. While driving heat can be used from 55°C up to 110°C at the inlet, reject heat inlet temperatures up to 45°C are feasible for standard operation. Even higher reject heat temperatures are viable without danger of crystallization. The only drawback is the lower cooling power density than specified in the project aims. Therefore, also operation in heat pump mode can be envisaged. The flow rates in external circuits are almost free to choose, with the variability for stable conditions limited to a range of 10-25% of nominal flows on the lower level. Various figures showing variations of temperatures and flow rates to operate chiller will be presented. System layout, including commercially available dry reject heat systems, allow for parasitic electric EER values lower than 6% of cooling load. Experimental results of the 50 kW absorption system surpass the performance targets while at the same time a lower price than offered by today's market seems to be achievable. System demonstration and development of up to 320 kW cooling load is under way and will be finished in 2012.