| In recent years, with the increasing demand of energy conservation and pollution prevention, the energy complementary applications were become a trend. Solar energy has greater impacted by geography and weather, even not well meet energy demand,air source have poor performance to adapt to low temperature.a combination that can achieve better energy use. In this paper, new heat exchanger in winter operation, the air go through the medium of a solar hot water pipes first, this will increase the air temperature, and then through the medium of refrigerant lines, the evaporation temperature increase and the unit COP improve also.The new heat exchanger can be more effective to solute the problems of the traditional outdoor heat pump air conditioning unit running low efficiency in winter, frost, defrost action frequent and improve the reliability of the device operation, have high efficiency characteristics. The design features can effectively improve the air source heat pump operating conditions in winter, reduce or avoid the frost of air source heat pumps, which can not only ensure efficiency of the system, but also achieve the purpose of energy saving.The design have significant social and economic benefits, and a great development and application potential.This paper firstly used by EVCP-COND heat exchanger simulation software to simulation and optimization the number of branches,form of flow path,In order to determine the optimal branches number of exchanger, and by way of three different forms of flow lines are optimized to get the best heat flow path layout, as a basis for determining the arrangement of the heat exchanger.Experiment was carried out on 60Kw-capacity heat pump unit with new heat exchanger in Enthalpy difference lab. Single air source heat pump operation and dual-source units performance were studied. Focuses on the changes of evaporator outlet temperature, the air temperature,the unit heating capacity, the total input power, energy efficiency of air source heat pump when affected by fan flow and ambient temperature,from the changes we can see when a single air source heat pump is running, the fan frequency adopt 25-45Hz have better plant performance.The experimental study of multi-source heating show SA-ASHP unit performance has improved significantly than S-ASHP, and with the increase of solar hot water temperature to enhance the effect is more obvious.When the solar hot water temperature 30 ℃ under standard working conditions(ambient temperature at 7 ℃), the unit heat exchange increase of 42%, up to 64.86kw. The unit energy efficiency can increase by 39%, increased from 2.26 to 2.91.With the decrease of temperature, heat transfer, energy efficiency of solar hot water conditions have significant increase than no solar hot water conditions,and with the ambient temperature decreases, the solar hot water has more significant role. The most significant increase is when the ambient temperature at -5 ℃ and solar hot water temperature is 20 ℃, the heat transfer and COP is increased by 23.3%,18.9%. than the conditions without solar water.By analyzing the utilization of solar hot water heating on the nominal conditions (ambient temperature at 7 ℃)we can see that the solar heating effect is significant when water temperature at.20℃.With the increase of water temperature, the air is gradually heated; When it reaches 30 ℃,the outlet air temperature from evaporate is above the ambient temperature,, the absorbed heat of evaporator is mainly from the solar water, while mbient air is no longer providing heat to the evaporator.When solar water temperature at 20 ℃ and 25 ℃,the utilization of solar collectors is around 58%, about 42% of the heat is dissipated to ambient air.When the water temperature at 30 ℃,the utilization decreased to 46.5%. Therefore, the optimum coll ector area is 112 m2 by further analysis with Trnsys,which plays a guiding role in the practial application of the unit. |
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