Objetivo To install in the Danish town of Frederikshavn a large Diesel driven heat pump, using sewage water as heat source for district heating. To demonstrate the heat pump's performance and energy saving capability in comparison with a conventional boiler of same capacity. The annual oil saving is estimated at 56% or 4420 tons.The heat pump plant was handed over to the Municipality of Frederikshavn, Denmark, at the end of October 1981.The heat pump now is integrated into the district heating system, where the base-load is produced by a garbage-burning plant. The total annual number of operating hours for the heat pump was expected to be around 6,500, but the actual needs of the town during the initial years of operation reduced this figure. The heat source is to the effluent from a sewage plant, with a temperature varying from 6 to 16 deg.C. The diesel engine runs on 1500 SRW fuel oil and it is found that the heat recovery system can be operated at stable conditions even though the exhaust gas is cooled to 30 degree before entering the chimney.All systems were tested under normal running conditions at different load levels and outputs. After elimination of start-up difficulties, including compressor problems, all systems functioned according to plan and test results were within expectations.The Primary Energy Ratio (COP) was found to be 1.87 at maximum output with the engine running on diesel oil, and 1.81 when running on heavy fuel (1500 SRW).ECONOMIC CONSIDERATIONS.Although total cost of this prototype heat pump plant came to 26.6 M. DKr (3.74 M. ECU), further installations would cost approximately 15.5 M. DKr (2.18 M. ECU) each, but would permit similar fuel savings.If the heat pump plant is regarded as a pure energy supplier (where there has generally to be a full stand-by production capacity), for a mean investment of 15.5 M. DKrs, the payback time would be 6.74 years.On the other hand, if the heat pump is regarded as an energy saving investment only, the additional investment with respect to a conventional boiler (approx. 5.5 M. DKrs) is to be considered; thus, to save 4420 tons of oil per year, an additional investment of 15.5 - 5.5 = 10.0 M. DKrs is required. In this case, payback time would be 4.4 years.These payback times derive essentially from annual savingswhich depend upon the price of fuel plus operational and maintenance costs. However, because the running time of the heat pump during its early years of operation was reduced for reasons that were totally independent of the system, the payback time of the Frederikshavn plant has increased.The project process can be described as a heat pump driven by a diesel engine. The heat pump takes energy from a low temperature heat source and delivers it to a district heating net. The diesel engine is equipped with a total waste heat recovery system, which gives a further rise in temperature of water supplied to the heating net.The heat pump plant is located in the area of the sewage plant near the existing discharge for the sewage water. the cleaned water is discharged to the sea after cooling in the heat pump. The heat pump plant, consists of :- a 3000 kW, 16 cylinder, 4 stroke diesel engine,- a gearbox to drive compressor and electric generator- a 710 kW electric generator with thyristor regulation,- a heat pump system consisting of a two-stage compressor, condenser, sub-cooler for liquid refrigerant, economizer, evaporizer and superheater for evaporated vapour,- a waste heat recovery system that picks up additional heat from the engine's cooling system and exhaust gases,- and a computerized automatic control system.The automatic control system adjusts and regulates the heatpump operation in accordance, with the temperatures of the district heating net and of the heat source (sewage water) which vary with seasonal conditions. A yearly maximum production of 11.5 MW of heat energy and 0.7 MW of electrical energy is achieved from the plant for an oil energy consumption of 7.7 MW. Programa(s) ENG-ENALT 1C - Programme (EEC) of financial support for projects to exploit alternative energy sources, 1979-1984 Tema(s) 1.3 - ENERGY INDUSTRY Convocatoria de propuestas Data not available Régimen de financiación DEM - Demonstration contracts Coordinador BURMEISTER & WAIN SCANDINAVIAN CONTRACTOR A/S Aportación de la UE Sin datos Dirección TORVEGADE 2 1449 Copenhagen Dinamarca Ver en el mapa Coste total Sin datos
