Using solar energy to cool
Light and heat from the sun have been used as energy sources since ancient times. The development of technologies such as photovoltaic (PV) panels, pumps and fans has facilitated the conversion of sunlight into useful energy outputs. Despite the energy potential of the sun, its applicability in cooling processes has been limited. This issue was addressed by the EU-funded project ‘Development and implementation of a cost effective adsorption refrigeration system utilising high temperature (120°C) solar compound parabolic collectors (CPC)’ (Socold). Consortium partners developed and implemented the prototype of the solar collector and also two adsorption refrigeration prototypes. Using compound parabolic concentrator (CPC) technology, an optimised plate collector was constructed that was capable of providing medium temperatures of up to 120 degrees Celsius during operation. This provided an important advancement to flat plates that could not provide a high enough temperature for the regeneration process of the adsorbent. The main innovation of this project was the development of two adsorption chiller prototypes working on different temperature levels. One machine aimed at a temperature level suitable for air conditioning and the second machine would be used for food preservation. The adsorption heat pump prototype consisted of four chambers: an evaporator, two adsorbers and a condenser. These were connected in such a way to lead condensed water permanently from the condenser to the evaporator, guaranteeing a continuous operation. Overall, the Socold CPC collector offered a good compromise between investment costs and efficiency and was, therefore, a very important development on the solar thermal market. Implementation of the product is expected to boost solar cold production.
