IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask A Report A-D3b, Date: December 2010
Configuration
Heat storage
Cold storage
Auxiliary heater
Use of auxiliary heating system
Auxiliary chiller
2 m 3 water
0.2 m³ water
District heat
Space heating in winter
no
System scheme
System performance
Over the summer period 2009 (July-Sept) a thermal coefficient of performance of 0.6 was
observed. About 1/3 of the cooling demand was delivered by free cooling, 2/3 by solar
cooling. The electrical coefficient of performance for free cooling was COPel = 1.8, for solar
cooling a COP el = 1.6 was measured. The overall coefficient of performance for the summer
period was approximately COP el = 1.7.
In the winter period from October 2009 to April 2010 the average coefficient of performance
for free cooling was about COP el . = 8.2, no solar cooling was observed.
System reliability and overall success of the installation
The whole system is running reliably but with a poor overall performance, especially the
electrical consumption is very high. The chiller was running very reliably throughout the
whole summer. It also brought the expected power level and reached a feasible COP as well.
Free cooling mode is activated mainly in night times and running on a poor power level. The
two largest electrical loads are the cooling tower and the pump towards the cooling tower.
These two consumers are responsible for more than 75% of the electrical consumption. The
reason for the high electrical consumption of the cooling tower is its high fan power which is
not speed-regulated. Due to this a high potential in the improvement of the control system
can be observed, mainly through an adequate control of the cooling tower. Small changes in
hydraulic design can also decrease the electrical consumption, especially for free cooling.
Photos
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