20 SMALL GAS-FIRED ABSORPTION HEAT PUMPS

Cel

An absorption heat pump (AHP) designed for heating small residential buildings was to be tested in practical operation. The test should prove the reliability and efficiency of this AHP and it should answer to the question whether the commercial use of the AHP will be possible or not. 15 units were planned to operate in single family houses and 5 units in the manufacturer's laboratory.
The 10 AHPs installed in residential buildings gave the following cumulative values:
Operating time: 35,728 h
Heating energy produced: 196,537 kWh
Gas consumption, related to natural gas with a calorific value of 8.30 kWh/m3: 20,087 m3
Auxiliary electric power consumed: 14,735 kWh
Based on these data, the average heating COP of all AHPs taken over the total operating time is 1.179. On the average, 73,6% of the heating operation were covered by the AHP.
As a matter of fact, with the individual AHPs, there were found considerable deviations from the average annual values, these deviations depending on the characteristics features of the installation and the individual requests of the users, f. ex.
Heating COP: 0.928 - 1.360
Demand in auxiliary power: 0.266 - 0.489 kW
Operating time quota: 50.9 - 98.7%
According to the individual data, the heating COP is the higher, the lower is adjusted the heating water flow temperature. The auxiliary power consumption which considerably influences the efficiency depends on the possible placing of the heat source air ducts and the water pipes connecting the AHP to the heating network.
The field test confirmed the performance data of the laboratory tests. In addition the winter operating conditions brought a lot of suggestions for improving the control system. Last not least several technical defects were disclosed, which can be eliminated now by comparatively few additional expenditure.
Economic aspects:
The AHPs installed in residential buildings brought the following average values:
Operating time: 3,573 h
Saving of natural gas L (compared to a boiler offering an annual COP of 0.7): 1,374 m3/unit
Excess consumption of auxiliary electric power compared to a boiler: 1,206 kWh/unit
Energy cost saving: 769. DM/unit
Due to this figures the energy prices of early 1983, when the project was submitted, and the predicted increase of these prices at that time would have defined a payback period of 7 years, related to the additional expense of the AHP compared to a boiler.
As a consequence of falling and now at low level stagnating prices of fuel oil and natural gas the effect of saving energy costs by using an AHP has been reduced to 25% of the abovementioned value. Taking into consideration the capital expenses required by the higher investment costs, it will be impossible to reach a suitable payback period, i.e. a payback period shorter than the service life of the AHP.
The project started in January 1984 and ended in September 1986. It was executed in 4 stages:
Stage 1
Modification of the prototype to a similar serial-construction
Stage 2
Production of 15 AHPs
Stage 3
Installation and taking into operation of 10 units in residential buildings in the Remscheid area and of 5 units at J. Vaillant GmbH
Stage 4
Record and evaluation of measuring data, after-sales service, after the conclusion of the test the dismantling and examination of the AHPs
The AHP was a gas-fired air-to-water heat pump using as agent NH3 and as solvent H2O. The nominal output was 12.5 kW at an outside temperature of - 5 deg. C. and water temperatures of 56/42 deg. C. In the case of higher heat demand, the AHP was cut off and a second heat generator took over the heating. The AHP and the second heater were provided with a common automatic control system allowing the automatic operation of the heating system and the continuous adjustment of the AHP's heat output depending on the real heat demand.

Program(-y)

ENG-ENALT 2C - Programme (EEC) of demonstration projects relating to the exploitation of alternative energy sources and to energy saving and the substitution of hydrocarbons, 1983-1985

Temat(-y)

3.1 - BUILDINGS

Zaproszenie do składania wniosków

Data not available

System finansowania

DEM - Demonstration contracts

Koordynator

JOHN VAILLANT GMBH

Wkład UE

Brak danych

Adres

BERGHAUSER STRASSE 40
5630 REMSCHEID 1
Niemcy

Koszt całkowity