Central solar heating

Central solar heating is the provision of central heating and hot water from solar energy by a system in which the water is heated centrally by arrays of solar thermal collectors (central solar heating plants - CSHPs) and distributed through district heating pipe networks (or 'block heating' systems in the case of smaller installations).

For block systems, the solar collectors are typically mounted on the building roof tops. For district heating systems the collectors may instead be installed on the ground.

Central solar heating can involve large-scale thermal storage, scaling from diurnal storage to seasonal thermal energy storage (STES). Thermal storage increase the solar fraction - the ratio between solar energy gain to the total energy demand in the system - for solar thermal systems. Ideally, the aim for applying seasonal storage is to store solar energy collected in the summer time to the winter month.

Compared to small solar heating systems (solar combisystems), central solar heating systems have better price-performance ratios due to the lower installation price, the higher thermal efficiency and less maintenance. In some countries such as Denmark large-scale solar district heating plants are financially fully competitive to other forms of heat generation.^[1]

Central solar systems can also be used for solar cooling in the form of district cooling. In this case, the overall efficiency is high due to the high correlation between the energy demand and the solar radiation.