ENERGY OPTIMIZATION OF A SOLAR COOLING PLANT WITH PCM HEAT STORAGE

摘要

A key factor for the energy optimization of a solar heating/cooling plant is the design of the heat storage, also related to the solar field size and performance. Latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. There are large numbers of PCMs that melt and solidify at a wide range of temperatures, making them attractive in a number of applications. This study aims to evaluate the potential of integrated solar absorption cooling and heating systems with "traditional" sensible versus "innovative" PCMs heat storage tank. The TRNSYS software tool was used as a basis for assessment for a typical residential building application. A first set of simulations was used to optimize the size of the solar collectors field varying the heat storage volume and the climate (three different locations were considered: Venice, Rome and Trapani (Italy)) for a sensible heat storage tank. The same optimization was implemented for a latent heat storage tank for four different PCMs and varying different characteristics (such as shape, size, arrangement) of the PCMs. Results indicate that the "PCM system" allows better annual energy performances with respect to the "sensible system". Anyway, these results are strictly connected to the temperature level of the phase change, and so to the solar collectors field size and characteristics, the storage tank volume and obviously to the temperature of the heat loads.