A case study based comparison between solar thermal and solar electric cooling

The need for energy for refrigeration purposes increases with the wealth of population in industrialized countries, thus it has been growing strongly in the last decades. One of the causes of hot temperature and the need for refrigeration is the solar radiation, therefore, it sounds reasonable to try to exploit this renewable energy resource to satisfy the cooling loads of buildings. There are different strategies and technologies to exploit the energy gathered from solar rays for this purpose. Two are the most common options in commercial applications: solar thermal cooling where the cooling is provided by an absorption chiller working thanks to a high temperature fluid heated by the Sun and solar electric cooling, which conversely adopts photo-voltaic panels to generate the electricity required to run a standard compression chiller. A comparison on large-scale case study represented by a hospital building has been carried out. The outcomes of the study evidence a strong dependence of the economic convenience depending on the assumptions made and the technical constraints. This enhances the importance of an accurate analysis of the location, the loads requests and the possible economic incentives, before the adoption of such technologies.