Heat Rejection Control Strategy for Stationary Tests of Discontinuous Thermally Driven Chillers
Abstract
Sorption machines for heating and cooling have the capability to be supplied with waste heat or heat out of renewable energy sources. Especially in areas with a high solar radiation in Europe, the use of thermally driven chillers have the potential to be an alternative to common compression chillers. In the summer period, when air conditioning in buildings is needed, sorption chillers can significantly reduce the high electrical energy consumption, reducing the load peaks on the electric grid. Therefore the development of this technology shows increasing interest. On this basis, since 2010, Eurac and Velta Italia began to collaborate at the development of an innovative standardized system used to cover thermal loads for heating, cooling and domestic hot water preparation, through the exploitation of a large fraction of solar energy. The project objective is the development of a system consisting of solar collectors, hot water tanks, a thermally driven chiller and a compression heat pump in combination with a floor distribution system, used for heating in the winter as well as for cooling in summer. The target selected are residential buildings with surfaces between 150 and 250 m2. Within this project, stationary tests were carried out in laboratory on the employed sorption machine to verify manufacturer’s performance values, to define and develop a control strategy for the heat rejection system and to validate simulation’s results. The paper presented shows the preliminary results of the stationary tests carried out to define a control strategy for the heat rejection system to be used both during the tests and on-site operation.