THERMAL PERFORMANCE OF SOLAR DISTRICT HEATING PLANTS IN DENMARK

摘要

The market for solar heating plants connected to district heating systems is expanding rapidly in Denmark. Itrnis expected that by the end of 2014 the 10 largest solar heating plants in Europe will be located in Denmark.rnMeasurements from 23 Danish solar heating plants, all based on flat plate solar collectors mounted on thernground, shows measured yearly thermal performances of the solar heating plants placed in the interval fromrn313 kWh/m~² collector to 493 kWh/m~² collector with averages for all plants of 411 kWh/m~² collector for 2012rnand 450 kWh/m~² collector for 2013.rnTheoretical calculations show that for temperature levels higher than about 55℃ the thermal performance ofrna solar collector field based on concentrating tracking solar collectors is higher than the thermal performancernof a solar collector field based on flat plate collectors.rnIt is estimated that there are potentials for further improvements of the cost/performance ratio for solarrncollector fields, both with flat plate collectors and with concentrating tracking solar collectors.rnIt is recommended to continue monitoring and analysis of all large solar heating plants to document thernreliability of the solar heating plants. It is also recommended by parallel theoretical and experimentalrnapproach to investigate in detail the thermal performance of differently designed solar collector fields in suchrna way that their thermal performance can be determined by theoretical calculations in the future. This will bernuseful in connection with development of improved solar collectors for solar heating plants and inrnconnection with optimization of future solar heating plants.rnFurthermore, it is recommended to continue the development of long term heat stores for solar heating plantsrnand to elucidate how best to integrate solar heating systems in the future energy system