Simple calculation tool for central solar heating plants with seasonal storage

Central Solar Heating Plants with Seasonal Storage (CSHPSS) are able to produce thermal energy from solar radiation during all the year providing a significant part of the residential sector demands for Space Heating (SH) and Domestic Hot Water (DHW), using district heating systems. The yearly dynamic simulation is a complex process requiring local detailed climatic and demand data in order to properly design/sizing the plant components to reach the desired solar fraction. In this paper is proposed a simple method for the calculation of CSHPSS using demand data and easy to find available public climatic data. The proposed method is a useful tool to evaluate the CSHPSS system at early project stage as well as to perform parametric analysis in order to establish optimization and design criteria. The method is completely described and applied for a specific location in Spain to size the main components of the system which are the solar collector field area and the volume of the seasonal storage. It is also applied to perform a comparative analysis of CSHPSS located in different climatic areas of Spain. The obtained results reveal that the location of the plant and the different demands corresponding to different climatic areas affect very significantly the sizing and design criteria of CSHPSS.