Abstract :
In April 2001 the new European Standard EN 12975:2000: ‘‘Thermal solar systems and components––Solar Collectors’’
was established. With the publication of this European standard all national standards, related to the same
topic, have to be withdrawn by the nations of the European Community. Now only one standard for testing solar
collectors is valid throughout Europe.
This European Standard specifies test methods for validating the durability, reliability and safety requirements for
liquid heating collectors. The standard also includes two alternative test methods for the thermal performance characterization
for liquid heating collectors. Apart from the well-known test method under steady-state conditions according
to ISO 9806-1, ISO 9806-3 and ASHRAE 93-77 the EN 12975 permits a quasi-dynamic test method for the
thermal performance characterization of solar thermal collectors.
This paper presents the improved approach to outdoor performance testing of solar thermal collectors under quasidynamic
test conditions. The test requirements and collector theory are closely connected to those long agreed on for
steady-state testing, as described in the ISO and ASHRAE standards mentioned above. The most important effects for
the all day performance of the collector are taken into account. The test method covers most collector designs on the
market today (except ICS type). Only some correction terms are added to the basic collector models of the present
steady-state test methods. Still this limited change will allow test data to be collected and used from whole days.
An important fact is that the collector model used for the parameter identification is written so that the error in
collector output power is minimized. Therefore an accurate long-term prediction of the collector performance can be an
integral part of the test method, where the same collector model and parameters are used for both testing and prediction.
2003 Elsevier Ltd. All rights reserved.
