| Gas-driven engine heat pump is a kind of heat pump device,which uses clean energy-natural gas as its input energy source.It has several advantages such as high primary energy ratio,wide range of operating ambient temperature,superior ability of refrigerant capacity regulating,do not depend on electric power supply.Under the government policy of energy conservation and pollution emissions reduction work,proportion increase of natural gas consumption,gas-driven engine heat pump has a broad application prospect.Thermal energy storage is a method of improving the energy consumption efficiency in users’ position.It serves for building energy conservation.This method is valued by more and more scholars.This paper focused on reducing building energy consumption and improving the matching degree of building load supply.The three points of building energy saving,gas-driven engine heat pump,energy storage were been united.Energy storage type gas-driven engine heat pump(ESGEHP)was established.The main research contents and results are as follows:The schematic and key components of ESGEHP system were introduced.The system’s heat balance model was analyzed and system theory model was improved.The efficiency evaluation method was given.Tests of the system which in the zone of economic engine speed(1200 r/min-2000 r/min)were been designed both in cooling season and heating season.Fuel consumption quantity,refrigerating capacity,heating capacity,heat recovery capacity and system efficiency were calculated.It was pointed out that the system is more economic and efficient in 1200 r/min-1600 r/min.When engine speed is higher than 1600 r/min,the economy will decline and operating efficiency will be lower.4 working modes of ESGEHP system were designed,including low load mode(Mode L),part load mode(Mode P),full load mode(Mode F)and over load mode(Mode O).The operating strategy was developed based on each mode.According to building load,system’s operating zones were divided.And the relationship between energy storage and building load was discussed.This paper used DesignBuilder software to build two types of models: Office Building and Villa.Building cooling and heating load simulation was carried out in four climatic typical areas including severe cold area,cold area,hot-summer and cold-winter area,hot-summer and warm-winter area.The composition of whole year cooling/heating load and daily variation characteristics of building load in different types of buildings were discussed.Application comparison between ESGEHP and GEHP system in a building in Tianjin was shown as: After using ESGEHP system,the daily average PER in summer testing day is reduce by 1.83% in order to maintain the balance of energy storage,but the fuel consumption is saved 7% and the matching degree of building load is increased by 79%.In winter testing day,the daily average PER is increased by 1.43%,fuel consumption is saved 3.8% and the matching degree of building load is increased by 37.5%.According to the simulation results of building load,applicability analysis of ESGEHP system was carried out.It was pointed out that ESGEHP system is especially suitable for areas with high winter heating load and low summer cooling load,which has obvious effect on buildings with large daily load fluctuation,and has better energy saving effect.The shortcomings of the traditional GEHP system that the load supply is too high at low building load and insufficient at high building load were solved. |
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