Solar District Heating Taking the Full Summer Load in Cities
Abstract
Solar District Heating has been used in combination with biomass to cover the summer heat demand, in new quarters to support heating and hot water with long term storage and in cities to replace a small portion of summer load coming from fossil fuels. This presentation will demonstrate that even in big cities- like Graz- the summer load can be completely switched from fossil fuels to waste heat and solar heat. This can be achieved by decentral use of area for placing the panels, integrating the existing volume of district heating and existing tanks as a storage to balance solar gains and demand. Moreover, through placing storage tanks at relevant customers the peak load management in winter can be supported with the same tank that is helping solar in summer to balance the energy flow. So additional customers can be supplied with the same distribution pipes used more efficiently. Technical and economical feasibility is proven; reduction of burning gas is a goal in most political programs. Still there is significant hesitation in district heating companies.