Skip to main content

Development and implementation of a cost effective adsorption refrigeration system utilising high temperature (120°C) solar Compound Parabolic Collectors (CPC) (SOCOLD)

Final Report Summary - SOCOLD (Development and implementation of a cost effective adsorption refrigeration system utilising high temperature (120°C) solar Compound Parabolic Collectors (CPC))

The performance of a thermal operated cooling device is of course strictly dependent on the particularly used heat source. The consortium of this project was not only aiming at the development of an adsorption refrigeration machine, but also on the optimization of the appropriate heat source. An advanced flat - plate collector with focusing characteristics utilising the so-called CPC (compound parabolic concentrator) technology would deliver energy on a temperature level of 120 degrees Celsius.

Besides the prototype of the collector also two adsorption refrigeration prototypes would be developed, implemented and scrutinised throughout the test stage. The main goal was finding alternative cooling methods for two different temperature ranges. On the one hand, air should be conditioned, on the other hand, cold should be provided on a temperature level of -20 degrees Celsius.

Adsorption is the reversible attachment of gas molecules within the pores of a highly porous adsorbent agent, whereby the vapour of the cooling medium is thermally compressed. The sorption agent is assembled within a heat exchanger and alternately - depending on the process stage - charged with either heating or cooling medium.

The most obvious advantage of adsorption refrigeration machines over conventional absorption and compression chillers is due to the fact that no moving parts in the depressurised areas of the device are needed.

The treatment of both adsorption agents and their combination with the active heat exchanger surface would be above all a target for possible innovations. Two prototype adsorption chillers, working on different temperature levels would be constructed and manufactured based on the gained results of these investigations and the end-user requirement specifications.

A final assessment of all project results in terms of economical, socio-economic and logistic aspects would be performed by local experts. A simulation tool, describing the whole process would be developed. This tool would help to dimension and design adsorption refrigeration chillers within the near future.

The adsorption heat pump prototype consisted of one or more heat pump modules, switching unit (pipes and valves), controller and electronic parts. Each heat pump module was divided into the four chambers evaporator, adsorber 1 + 2 and condenser, which were connected by self operating steam valves. The external re-circulation would lead condensed water permanently from the condenser to the evaporator; so a continuous operation was guaranteed.

The purpose of this system was to provide cold on a temperature level of 0 degrees Celsius to -4 degrees Celsius. The final application area of FROST was the conservation of perishable products like food. The system has been constructed and was installed in July 2006 at the Asociacion of the Meat Industry of Asturias (Noreña, Spain).

The main innovation of this project was the development of two adsorption chiller prototypes working on different temperature levels. One machine would aim at a temperature level suitable for air conditioning and the second machine would be used for food preservation where temperatures around the 2 degrees Celsius were needed.

The optimised CPC collector was capable of providing medium temperatures of up to 120 degrees Celsius during operation. This was of great importance for new applications of adsorption chillers within the context of solar air conditioning or cooling. Normal flat plate collectors could not provide high enough a temperature for the regeneration process of the adsorbent. Consequently, costly vacuum collectors had to be implemented to run available ab- or adsorption chillers. The new CPC collector offered a good compromise between investment costs and efficiency and was therefore a very important development on the solar thermal market, which would help to boost solar cold production.

Related documents