Dynamic Matching Feature Of Hybrid Heat Sources For Ammonia Absorption Heat Pump

Ammonia absorption heat pumps, as a common form of absorption heat pump,due to its well adaptation in the north cold area and energy saving potential are widelyapplied. The heat source of the generator of the absorption heat pump can useparabolic trough collectors, which can automatically tracking the sun, to collect heat.However, due to the influence of random factors, such as days and nights, sunny orcloudy days etc., the solar radiation reached on the ground is intermittent and unstable.Just rely on the heat gained by parabolic solar collectors to drive ammonia absorptionheat pump in cold region is not sufficient. To meet the needs of heating demand, athermal oil boiler, as the auxiliary equipment, is needed. The matching problems ofthe two are studied in this paper.According to the actual design condition, the hourly heat load of the building inwinter seasons were calculated, and then according to the performance of ammoniaabsorption heat pump, the heat load needed for the generator side was calculated.Then a program was written to calculate the heat gained by parabolic solar collectorsand thermal oil boiler according to the designed condition of the system. The dynamicmatching properties of the parabolic collectors and the thermal oil boiler wereanalyzed under the influence of many factors such as outdoor temperature and directsolar radiation. In the paper the index of solar contribution was put forward toevaluate the solar heat gain of the total heat demand. The paper also analyzed theadvantages and disadvantages of the absorption heat pump driven by composite heatsource. Finally, the paper calculated the energy consumption of the absorption heatpump and regular electric heat boiler for the building heating, and the payback periodof investment and the impact on the environment. In addition, the best solar collectorarea was calculated, which guarantee low utilization rate of thermal oil boiler andinitial investment of the system.The results show that the heat gained of parabolic solar collectors and heatdemand of thermal oil boiler are influenced by various factors and change with factors.It has the minimum solar contribution in November. With the area of solar collectorsincrease, solar contribution increased. Driven by the composite heat source, in the first few hours, it need electrical heating auxiliary, then in the following hours, parabolicsolar collectors can completely meet the demand of heat of generators and thus thesystem meets the load of the office building in Tianjin. Compared with electric hotwater boiler, the energy consumption of ammonia absorption heat pump can savecosts about65000Yuan every year, reduce carbon emissions58984kg, and thepayback period is14.5years. The optimum collector area was determined throughinitial investment and the utilization rate of thermal oil boiler. When the area of solarcollectors of each group is60m2, it has the lowest initial investment payback period.