Performance of Riga District Heating Rehabilitation Project in Aspects of Automated Control

Abstract

In the interconnected Rigas Siltums district heating system the only safe alternative for reconstruction of customer substations is to replace the elevator points by automated individual Heat Substations (AIHS) comprising heat exchangers for both the domestic hot water and for the space heating. This results in major benefits for the District heating system. First, it is a natural boundary between the district heating system and the building internal side, and the responsibilities can be easily defined. As the primary and the secondary sides will be separated by heat exchangers, the distribution system can be operated at the higher pressure if required for optimized utilization of the plants. The temperature level in the building radiator system is independent of temperature in the distribution system. All water losses in the building will be the responsibility of the building owner, and he will have all the incentives to prevent leaks. Any water leakages from the building heating system will only result in rather small amounts of water compared to the volume available when the whole district heating system is directly connected