MeQuSo – Development of methods for quality as-sessment of large solar thermal plants under real operating conditions

Heat consumers of large solar thermal plants usually demand guaranteed minimum yields from the plant builder or operator. In solar contracting, operator and customer agree on the heat price beforehand. This places high demands on the technical and economic planning reliability. The correct forecast of the solar yield is hindered considerably by the uncertainty about the thermal performance of the deployed collectors under the given operating conditions.

After the inauguration of a solar thermal plant, the performance needs to be assessed and it has to be evaluated if the guaranteed yields have in fact been reached (proof of yield). As the operating conditions (weather, system temperatures, load profiles, etc.) can considerably deviate from the calculation assumptions, there is no easy answer to this question.

The project MeQuSo addresses these issues by developing an in-situ test of the power output for large collector arrays and pratical methods to prove the power output and solar yield of large solar thermal plants.

The aim of the in-situ power output test is to assess the thermal performance of the deployed collectors under real operating conditions in the field. This test adapts the quasi-dynamic collector test according to ISO 9806:2013 to collector arrays. Contrary to the norm test, this test can be carried out based on commercial measurement equipment, as it is customarily available in large solar thermal systems.

Regarding the methods to prove the power output and solar yield of large solar thermal plants, the collector is in the spotlight. The methods are based on data gained during plant operation and should be applicable to commercial measurement equipment as well. After a short period, it shall be assessable if the collectors and the solar system as a whole meet the targeted yields.