ABSTRACT
A research programme “Solarthermie 2000” has been launched in Germany focussing on the development and market introduction of large solar heating plants without and with seasonal storage in the period 1994–2000. The first two pilot plants with seasonal storage will be realized under this programme in Hamburg (3,500 m2 collector area and 5,000 m3 water storage volume) and in Friedrichshafen (5,600 m2 collector area and 12,000 m3 water storage volume). This paper describes the optimization of the overall system including heat storage, collector array, distribution network, house substations and control strategy. The overall economic optimization also includes the cost/savings ratio of additional insulation and the heat distribution system in the houses. The thermal performance of the whole system including the houses has been simulated with the program TRNSYS 13.1.
The fuel consumption for heating and domestic hot water in the Hamburg project will be about 40 kWh/(m2a) when related to the living area which means a 75 % reduction compared to 1994 German standard. The fuel demand in the Friedrichshafen project will be 45 kWh/(m2a) and 70 % savings compared to the 1994 standard. The solar contribution in the project in Hamburg is 64 % and 50 % in Friedrichshafen. The solar heat costs in the two projects are 0.33 DM/kWh in Friedrichshafen and 0.39 DM/kWh in Hamburg. Solar heat from large plants with seasonal storage has similar or lower costs as most additional insulation measures.
