Solar thermal cooling

In a solar cooling installation, a solar thermal collector system drives a thermally driven chiller, such as an adsorption chiller. A very elegant aspect of solar cooling is the close match of supply and demand: cooling is mostly needed during times of high solar irradiation.

The main function of storage in a solar cooling installation is peak shaving. In times of low cooling demand, the storage is charged; in times of peak demand, the chiller and storage are turned on simultaneously, providing the required peak cooling power.

Storage is a valuable addition to conventional compression coolers as well. Having a diurnal storage makes it possible to run the cooler at night, at low electricity prices, sharply decreasing the operating costs of the cooling system. In addition, this decreases the electricity demand during peak hours, decreasing the load on the grid and the chance of blackouts.

The solar cooling market

With 64 million units sold, the world residential air conditioning market grew by 10% in 2006, and continues to expand steadily. The main reasons for this expansion are the rapid growth of the Chinese market and the recent heat waves in Europe, doubling the AC demand.

The Chinese market reached over 20 million units in 2006, becoming the world's largest single market. The market did not grow more rapidly than in 2004-5, most likely due to the rapid economic growth, the worsening situation of electric power supply, and the recent government policy reinforcing control on the real estate boom. The USA and Japanese markets have remained stable at 16 million and 8 million units sold, respectively.

Because solar cooling is still a young technology on the market, the residential cooling market is currently still completely dominated by "on-demand" compression coolers.

However, with the expected increase of blackouts in the electricity grids, combined with a rising electricity price, the market for solar cooling systems, and as such for advanced cold storage systems, is expected to grow rapidly over the next few years.

More information

This information is also available in an information leaflet on thermal energy storage for solar heating. More details can be found in one of the PREHEAT reports, Heat storage technologies: markets, actors, potentials.