Solar cooling is currently still one of the less well-known technologies. Many customers are unaware that a solar plant can also be used for cooling purposes. But the idea is in fact very simple: In summer, when there is an increased demand for cooling because of the solar radiation that occurs, the energy which is obtained is utilised to drive a thermal refrigerating machine that provides the necessary cooling capacity.
Simplified diagram of a solar cooling system:
1 Collector field 4 Back-up heating system
2 Heat exchanger 5 Absorption refrigerating machine
3 Buffer store 6 Cooling tower
Solar energy is a solution that provides promising opportunities. It can be used in virtually all buildings to operate the cooling circuits and therefore to air-condition rooms. The cooling load is usually provided if solar energy is available and therefore the cooling demand of a building is approximately equivalent to the solar radiation. Solar air-conditioning systems are usually operated with entirely non-hazardous operating liquids such as water or brine solutions. They are energy-efficient and environmentally friendly and can be employed either as independent systems or in conjunction with conventional air-conditioning systems. The primary aim is to use solar technologies with "zero emissions" to reduce the level of energy consumption and CO2 emissions.
Solar cooling has lots of advantages:
• Solar cooling is particularly useful in the summer months because of the increased
amount of solar energy that is available and the demand for cooling energy.
The match between the plants performance profile and the consumption profile
makes it possible to have a very efficient energy supply system without the need
for a large store.
• Conventional air-conditioning systems have a substantially higher level of electricity
consumption, which represents an enormous load for the power grids. For solar
cooling, only approx. 20 % of the power needed for conventional cooling is required.
• Solar plants are environmentally friendly. Solar cooling reduces the burden on the
environment to a minimum. These plants are operated with environmentally
friendly refrigerants and they do not emit any CO2 emissions. This represents a
significant step towards achieving the EU’s climate targets.
• Compared to conventional cooling systems, the life time of the components of a
solar plant is substantially longer (20-25 years).
• Cost savings also play a crucial role.
This means that the ongoing energy costs, e.g. for gas, coal, oil, are substantially
reduced as the solar cooling is operated using solar energy.
Costs are only incurred for any back-up system that may be required.
• As solar plants contain virtually no moving parts, the maintenance and repair costs
are reduced considerably.
Possible areas of use for solar cooling:
• Office buildings
• Multi-family houses
• Industry and commerce