Cogeneration Unit with Absorption Heat Pump for DH System

District heating systems proved to be among the most efficient energy supply systems for the cold climate regions. They are comparatively easy to optimize to ensure high efficiency. District heating plant Imanta has undergone several reconstructions in order to become a high efficiency boiler plant. Firstly the ordinary boiler plant with steam and hot water boilers has been reconstructed to be the cogeneration plant supported with the hot water boilers. Then one of the cooling towers has been replaced by the absorption heat pump/chiller thus installing the closed cooling water circulation system and recovering 2 MWth low grade heat otherwise lost in the atmosphere and producing atmospheric pollution. The driving force for the absorption heat pump is steam produced by the steam boiler already located in the boiler plant. The efficiency of the absorption heat pump is closely related with the supply and return water temperature regimes of district heating network. They are regulated according the actual outside temperature. The more efficient energy production system allows decreasing the fuel consumption for the same amount of the produced energy with lower expenses for the energy production and reduced amount of the polluting emissions into atmosphere.