The Technical University of Denmark does research in large-scale solar collectors.

Abstract from DTU-homepage regarding the conference publication:

The test method of the standard EN12975-2 (European Committee for Standardization, 2004) is used by European test laboratories to determine the efficiency of solar collectors. In the test methods the mean solar collector fluid temperature in the solar collector, Tm is determined by the approximated equation where Tin is the inlet temperature to the collector and Tout is the outlet temperature from the collector. The specific heat of the solar collector fluid is in the test method as an approximation determined as a constant equal to the specific heat of the solar collector fluid at the temperature Tm. The power produced by the solar collector during a test period is determined by the product of the specific heat, the mass flow rate and the temperature increase of the solar collector fluid. The solar collector efficiency is in the standard determined by measurements at different temperature levels. Based on these efficiencies, an efficiency equation is determined by regression analysis. In the test method, there are no requirements on the ambient air temperature and the sky temperature. The paper will present an evaluation of the test method for a 12.5 m² flat plate solar collector panel from Arcon Solvarme A/S. The solar collector panel investigated has 16 parallel connected horizontal absorber fins. CFD (Computational Fluid Dynamics) simulations, calculations with a solar collector simulation program SOLEFF (Rasmussen and Svendsen, 1996) and thermal experiments are carried out in the investigation. The investigations elucidate: • How the mean solar collector fluid temperature Tm is underestimated by the approximated equation in the test standard and how the collector efficiency equation is influenced by the underestimation of Tm. The dependence of the volume flow rate is shown; • How the use of the approximated specific heat of the solar collector fluid is influencing the collector efficiency expression; • How the temperature levels used is influencing the collector efficiency expression; • How the measured collector efficiency is influenced by the weather conditions such as the ambient air temperature and the sky temperature. Based on the investigations, recommendations for change of the test methods and test conditions are considered. The investigations are carried out within the NEGST (New Generation of Solar Thermal Systems) project financed by EU.

The Danish Engineering Newspaper did present the following news about a new very large CSHP plant:

Place: Denmark, Brænderup (near Horsens), at the mainland.

Size: 8.000 m² solar collector field, sized to deliver 10% of the district heating demand.

Of the 13 million total cost, the 3.5 millioner DDK are funded by a public body, Energinet.dk, that last year did analyse solar and district heating lead to positiv economical results. This analysis pointed out that this is due to the fact that the heat- or power plant can be turned of for some periods, where the price for power is too low to produce.
The maximum effect is estimated to 6 MW heat, with an annual production of approx. 4,000 MWh heat, leading to a yearly emission reduction of 4,300 tons CO2. The plant is designed by consultant company Planenergi and Ramboll, Denmark with Arcon solar collector producer, the same companies as involved in most of the plants in Denmark.