Solar Water Heater with PCM

The one of the most important part of a solar collector system is the solar tank. The solar collectors work daytime only, and its power depends on the weather. The hot water consumption in family houses is generally bigger in the evening and in the morning, so it is necessary to store the utilized energy. The collectors transform but not store the solar energy. The storage is necessary to accomplish in a heat-insulated tank, placed in tempered space. According the current architectural tendencies the boiler rooms are smaller, so the putting of the currently available solar tanks is very difficult. It is necessary to store the energy in a little space. The solution of the problem is the solar tank particularly filled with phase change material. This tank has smaller dimensions and bigger heat capacity than the conventional tanks. The other important advantage of a PCM solar tank is the possibility of the operating of the collectors at lower temperature. It could result a higher efficiency of the solar collector system. The storage system consists of two simultaneously functioning heat-absorbing units. One of them is a solar water heater and the other a heat storage unit consists of PCM. The solar water heater functions normally and supplies hot water during the day. The storage unit stores the heat in PCM.s during the day and supplies hot water during the night and overcast periods. The storage unit utilizes small cylinders made of filled with paraffin (PCM) as the heat storage medium and integrated with a solar collector to absorb solar energy. The performance of this PCM based thermal energy storage system is compared with conventional sensible heat storage system and the conclusions drawn from them are presented.