Solar cooling

Cheap, autonomous cooling system opens up new possibilities • 13 Aug 2015

A new TNO concept enables cheap, sustainable cooling that, in contrast to air-conditioning, for instance, does not depend on external energy like electricity. This is particularly useful where electricity is either absent, expensive or subject to unreliable supply.

The first application for this is a joint project in India whose aim is to establish an efficient cool chain for food products from source to supermarket, thereby reducing the deterioration of the vegetable and fruit harvest and thus loss of income for rural growers.

The technology combines existing concepts like adiabatic cooling with new elements like use of solar heat. Cooling at night or during cloudy conditions is possible through smart buffering. Depending on the level of humidity, the system provides not only cooling but also water.

How does it work?

The TNO Solar Cooling System, a pilot of which is soon to be built, uses an environmentally-friendly solution that extracts the water from humid warm air. Solar heat is used to extract that water from the solution and to transport it as water vapour to the dried air. There the water vapour is adiabatically cooled and the air becomes some 15 degrees cooler. TNO believes there are possibilities to lower the temperature even further.

Self-sufficient and cheap

The main benefits of the system are that it is entirely self-sufficient and its operating costs are very low during use. It is robust with a long life expectancy, and the use of existing technology and cheap materials make the price of the end product low. The system is able to supply cheap, environmentally-friendly and stand-alone cooling in countries with a lot of sun. The first application in India is geared to cooling cold stores and trucks in rural areas. However, since air-conditioners make up 40% of India’s electricity consumption, the application seems to be an obvious alternative to air-conditioners in buildings. Closer to home, there is also potential in the leisure market (campers, caravans).


Through further application of the system TNO also sees possibilities to employ the same principle to extract CO2 from biogas and make it suitable as a fuel, which would give people in remote rural areas the chance to quickly and cheaply convert biomass into a gas that can be used as a fuel for transport and cooking. TNO is investigating these possibilities via the EU Switch Asia Programme.


TNO offers India a new solar-based cooling application for food security

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