Preliminary experimental results with a solar driven ejector air conditioner in Portugal


A small scale solar driven air conditioner is described.

It is composed of solar thermal collectors and an ejector cycle.

Experimental results with system performance indicators are discussed.

Average thermal COP of 0.26 and electrical COP of 4.3 were obtained.

Adequate choice of spindle position improved COP by 35%.


The first experimental results with a small scale solar driven ejector cooling system installed in Porto, Portugal are reported. The system is constituted by three sub-systems: solar collector field, cooling cycle and thermal energy distribution sub-systems. The novelty in the cooling cycle is a 1.5 kW nominal capacity variable geometry ejector using R600a as working fluid. The integrated system is designed such that it can be used for cooling (summer) and heating (winter) of a 16 m2 test room. Experimental performance data, including e.g. collector efficiency, COP, cooling power, were collected between April and July 2016. The results indicated that the cooling capacity ranged from 1 to 2 kW depending on the operating conditions. Thermal COP of the ejector cycle was found to vary between 0.15 and 0.40. Average electrical COP was 4.6. The results indicated excellent working stability on clear days and on partially cloudy days with short interruptions of the solar radiation (<20 min). The benefits of using a variable geometry ejector and optimal operation are also demonstrated.


  • Solar air conditioning;
  • Ejector cooling;
  • Variable geometry ejector;
  • Experimental work;
  • Performance analysis

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