Skip to main content
European Commission logo print header
Contenu archivé le 2022-12-27

GAS ENGINE POWERED HEAT PUMP WITH HEAT EXTRACTION FROM THE SOIL FOR SPACE HEATING

Objectif

The aim of the project is to demonstrate the use of a gas compression heat pump with the soil as heat source in the heating range power above 1 000 kW. Energy savings of 50% compared with a conventional boiler plant are envisaged.
During the heating periods 1982/83 and 83/84 there were longer non-availability periods of the plant mainly due to damage of the soil heat exchangers, corrosion problems in motor heat exchangers, motors failures etc.
In the heating period from October 1983 to end of April 1984 - excluding the three months interruption due to the motor failure - 919.7 MWh were produced at a gas consumption of 558 MWh, corresponding to an average PER of 1.51 or an energy saving of 51.5% compared with conventional production by the gas boilers with 80% efficiency.
Although the actually measured heat demand was in a very good accordance with the design, the expected energy cost savings were not reached. This means that the total operating costs of the gas heat pumps are always higher than those of the gas boiler. It is estimated that break even can be reached at 160% higher than today's (1985-86) gas cost value.
The heating plant of the district building in Warendorf consists of a combination of two gas heat pump units with three gas boilers to cover the peak load and produce hot water. The heat pumps are dimensioned for coverage of the transmission heat demand of 1 150 kW, two soil heat exchangers (6 800 m2, 2 100 m2) are used as heat source for the heat pumps, the heat exchangers consist of pe-tubings in parallel one besides the other in plane, they are installed in 2 depths of 0.8 and 1.8 beneath the soil surface.
The building under consideration having 17.700 square m. of heated area, was designed to have a K value of 0.2 W/square m.K. and the load was calculated under 21 Deg. C inside and 12 Deg. C outside design temperatures.
The infiltration coefficient was taken as 9,4 cubic m/h sq. m. of window surface, corresponding to an air charge of 1 time per hour.
At present energy price levels the heat pump heating capacity was designed to be about 60% of the total transmission heat demand. The construction of the plant implies the combination of both heat pumps connected to a common evaporator and condenser. Each screw compressor used, being slide valve regulated, is directly coupled to gas-otto 6 cylinder drive engine rated at 13 kW output. The refrigerant R-12 is evaporated in a flooded type evaporator of 440 kW capacity, at 10 Deg. C evaporating temperature. The condenser is an ordinary bundle type condenser, rated as 680 kW, at 55 Deg. C condensing temperature.
Heat is extracted from soil and rain water using a brine circuit operating at 2 to 5 Deg. C lower than corresponding soil temperature, and 5 Deg. C temperature differential across the evaporator. The maximum heat absorption coefficient amounts to 49 W/sq. m. of soil area.
Heating water flows first through a low temperature circuit operating at
50.9 Deg. C, and consisting of the oil-coolers, condenser and gear coolers. A partial flow of the heating water is then passed through the high temperature circuit operating at 63.5 Deg. C, consisting of the motor jacket heat exchanger and waste gas heat exchangers. A buffer store integrated into the heat pump system stores the high temperature heat and supplies the impulses for switching on and off the heat pumps and the boiler.
A special characteristic of this installation is that the mechanical room is located in the attic of the building and sound proofing is ascertained by a proper design.
Saving of 51.5% versus 55 % expected.

Appel à propositions

Data not available

Régime de financement

DEM - Demonstration contracts

Coordinateur

KREIS WARENDORF
Contribution de l’UE
Aucune donnée
Adresse
LANGE KESSELSTRAßE 4-6
4410 WARENDORF
Allemagne

Voir sur la carte

Coût total
Aucune donnée