In solar thermal installations with large capacity, both solar cooling and solar heating are provided synergistically, yielding a complete annual utilization. During the cold season, solar heat serves for space heating. During the warm season, solar heat is converted into useful cold by means of sorption cooling devices, avoiding overheating of the solar thermal system. A favorable situation is given when radiative heating and cooling facilities, e.g., floor or wall heating systems or activated ceilings, are applied for transferring heating and cooling to the room at moderate heating and cooling temperatures.
Low-temperature heat storage based on phase-change material can be applied to cope with the given system requirements. During heating operation, the PCM heat storage balances heat generation by the solar system and other heat sources and the supply to the consumer. Thus, a low operating temperature of the solar thermal system is accomplished, yielding efficient operation with optimum solar gain. In cooling mode, the PCM heat storage serves as a reject heat sink for the absorption chiller in addition to a dry cooling system. By that means, heat rejection of the chiller is shifted to periods with lower ambient temperatures, i.e., nighttime or off-peak hours, and, thus, the necessity of a wet cooling tower is eliminated, allowing for a substantial reduction in operational effort, water consumption, and cost.
A detailed discussion of the system concept together with a modeling of the annual operation are presented. The thermal design of the PCM heat storage and preliminary experimental results are discussed.
Units: Dual
Citation: ASHRAE Transactions, Vol. 113, pt 1, Dallas 2007
Product Details
- Published:
- 2007
- Number of Pages:
- 8
- File Size:
- 1 file , 2.1 MB
- Product Code(s):
- D-DA-07-010
