Solar cooling with water–ammonia absorption chillers and concentrating solar collector – Operational experience

Concentrating solar collectors provide high efficiency at high driving temperatures favourable for thermally driven chillers. Therefore, they offer applications for hot climates and industrial process integration, especially in combination with NH3–H2O chillers that provide refrigeration temperatures below 0 °C. The presented solar cooling installation comprises a linear concentrating Fresnel collector that provides the driving heat for two NH3–H2O absorption chillers at temperatures up to 200 °C. Chilled water temperatures are produced in the range between −12 °C and 0 °C. Collector capacities reached up to 70 kW at peak times and the total cooling capacity of both chillers showed peak values up to 25 kW. For good operating conditions, the thermal system EER was 0.8 and an electrical system EER of 12 was easily achieved. The system showed a sound operating behaviour. The performance of different operation and control strategies was analysed, evaluated and enhanced within the two year operation phase.