IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask A Report, Date: November 2010
4 Monitoring Results
4.1 Annual / Monthly Data
As an overview the solar energy source management is shown in Figure 5. Start of
monitoring is July 2009 at the left side of the graph. The first cooling season lasts until
October 09 including free cooling. Q3 represents the sum of solar heating and the heat from
the conventional system. The solar fraction in summer is 100% (no heat backup) in winter
the solar fraction for heating drops down from approximately 20% in Nov09 to 7% in Dec09.
The highest fractions occur in spring (30% in Feb10; 60% in March10). The overall solar
efficiency is approximately 30%, including efficiencies up to 40% in summer and 10% during
winter.
Figure 5: Solar energy management over the whole measuring period July 2009 to
September 2010
In the first cooling season the primary energy ratios (PER) of the SHC plant are lower than
the defined reference system (Figure 6). As a result of these PER negative savings in terms
of primary energy occurred!
After improvements and changes in May 2010 the fraction of primary energy savings got
slightly positive. Higher values are expected for the cooling season 2011 with further
improvements. Since operation started in July 2009 savings of 14% could be achieved. If the
first (negative) cooling period is excluded the fraction of primary energy savings is greater
20%. Taking into account the 100% solar cooling plant with no conventional backup this
value has to be improved.
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