Solar Water Preheating for Open District Heating Nets – Optimization of the Air-To-Water Heat Exchanger Design
Abstract
District heating nets for heat supply are very common in cities of the CIS. In contrast to the EU countries some district heating nets in the CIS are constructed as an open-circuit system regarding the hot water supply (Budig et al. 2008)1, e.g. in Bishkek, the Capital of the Kyrgyz Republic. In such systems hot water itself is delivered to the consumers via the district heating net, whereas in closed systems only heat is supplied. A simplified scheme of an open-circuit system of the combined heat and power plant (CHP) in Bishkek is shown in Fig. 1. This district heating net supplies 350,000 inhabitants in the city center with the base load of around 2,600 m³ of hot water per hour and the peak load up to 3,000 m³/h. Beside this CHP in Bishkek there are over 60 boiler houses with much smaller open district heating nets for remote city areas.