Abstract :
In this paper the realistic behaviour and efficiency of heating systems were analysed, based on long term monitoring
projects. Based on the measurements a boiler model used to calculate the boiler efficiency on a monthly basis was evaluated.
Comparisons of measured and calculated fuel consumptions showed a good degree of similarity. With the boiler
model, various simulations of solar domestic hot water heating systems were done for different hot water demands and
collector sizes. The result shows that the potential of fuel reduction can be much higher than the solar gain of the solar
thermal system. For some conditions the fuel reduction can be up to the double of the solar gain due to a strong increase
of the system efficiency. As the monitored boilers were not older than 3 years, it can be assumed that the saving potential
with older boilers could be even higher than calculated in this paper.
2006 Elsevier Ltd. All rights reserved
