Enhancing district heating performances with solar thermal energy use: a case study at 2,000 m above sea level

The paper presents a study on the integration of a solar thermal system in an existing DH system in a mountain village. The system is located at approximately 2,000 m above sea level and the total number of buildings supplied by the network is 180, for a total heated volume of approx. 1,000,000 m3. The energy is currently produced by five natural gas engines and eight boilers, for a total available thermal power of about 30 MW. The high altitude of the location and the consequent clear atmosphere, and the long presence of the snow on the ground determine a very high level of direct, diffuse and reflected solar radiation. A solar thermal system can be an interesting solution for the reduction of the operating cost of the existing system. Large surfaces are available near the heat and power production site and on the roofs of some of the main thermal users, widespread along the net. A preliminary analysis of available solar radiation and sizing of the solar system is developed in the paper, to determine the optimal configuration to maximise the contribution of renewable energy in the DH system.