Optimization of the air-to-water heat exchanger configuration and system integration in multicomponent solar thermal systems
In the former Soviet Union often "open" district heating networks have been built in the past. In contrast to the usual Central European technology while the hot water is taken directly from the district heating network without intermediate heat exchanger. The appropriate amount of cold fresh water is fed centrally in the district heating plant and brought by burning gas or coal on the (summer) use temperature of about 60 to 70 ° C. This construction of district heating networks makes the use of solar collectors interesting because, for example in district heating Bishkek (Kyrgyzstan) must be heated in the summer per hour between 2,000 m³ and 4,000 m³ of water from 12 ° C to the use temperature niveau. But not only the high rate of fresh water with very low inlet temperatures makes many sites with open district heating networks in the former Soviet republics attractive for the use of solar energy. A preliminary experiment with non-covered panels in Bishkek showed that due to the special geo-climatic conditions (strong continental climate) in addition to the exposure, the enthalpy of ambient air can be used for heat gain. In a cooperative project, which is funded by the Volkswagen Foundation, a new type of solar thermal system has been built to produce hot water in collaboration with scientists from the Kyrgyz Technical University in Bishkek in summer 2004 for the first time. The system was previously developed at the University of Kassel and then installed on the heating plant "rotor" in the district Djal capital.
- Kirgisische Staatliche Technische Universität, Bischkek, Kirgisistan
- Bischkekteploenergo (Betreiber der ca. 60 Heizwerke in Bischkek)