Monitoring and simulation of an existing solar powered absorption cooling system in Zaragoza (Spain)

In 2007 and 2008 the performance of a solar powered absorption cooling installation was analyzed. The solar cooling system consists of 37.5 m2 of flat plate collectors, a 4.5 kW, single effect, LiBr–H2O rotary absorption chiller and a dry cooler tower. The performance analysis of the solar driven chiller shows average values of COP close to 0.6 in 2007 and between 0.46 and 0.56 in 2008. Concerning to the average cooling power, the chiller reaches values between 4.0 and 5.6 kW in 2007 and between 3.6 and 5.3 kW in 2008.During the analysis phase, a detailed model of the solar cooling system was developed using the simulation environment TRNSYS. The results of the simulation were validated with the experimental ones, and presented in this paper. The measured data as well as the simulation results of the installation show the strong influence of the cooling water temperature and the generator driving temperature on the COP. For this reason an alternative heat rejection sink was design. Among the alternatives, a geothermal sink was chosen since there is a water well located in the surroundings of the solar cooling installation. The first results of the studies carried out show an improvement on the COP up to 42%.