空调热水器系统研究毕业论文外文文献翻译.docx

1、空调热水器系统研究毕业论文外文文献翻译外文翻译(英文原文)ABSTRACTThe working principles and the basic features of air conditioning water heater (ACWH) system are introduced in this paper. The air conditioning water heater system can operate in five modes: water-heating only, space-cooling and water-heating, space-heating and w

2、ater-heating, space-cooling, space-heating. Comparatively, the system can provide much better energy performance and higher equipment utilization throughout a year, and cause less thermal pollution than heat pump water heater and common air conditioner. A prototype with five modes was assembled and

3、tested at the ambient temperature from -7 to 43, especiallywhen frosting. When it works in the water-heating mode, it can supply 55 hot water within two minutes, and thecondensing pressure is just same with common air conditioner. When some modes switch, the temperature of theoutlet hot water is con

4、stant. Theoretical analysis and experimental study were done to the ACWH in this thesis:1. The prototype was tested in the air-conditioner laboratory of GREE. The testing data indicate that the prototypeaccords well with the national standards of air conditioner and heat pump water heater.2. Based o

5、n the experimental results, analysis was done on the ACWH in main operating modes and some importantconclusions were given，The results indicate that the new system can save energy through multi-duties, and it can work stably in five workmodes with high efficiency. Compared with other models, the new

6、 system also includes air-conditioning unit andwater heater unit, but with fewer components and higher reliability. Based on common air conditioner, this systemcan offer a practicable solution coupling air conditioner and water heater. It must be changing the markets of bothair conditioner and water

7、 heater. 1. INTRODUCTIONThe heat pump water heater (HPWH) has been used since 1950s, mainly for household applications. It absorbs heatenergy from the ambient air to acquire hot water. In the last 20 years, the study intends to design heat pump waterheater with high reliability and practicability, a

8、nd many manufacturers turn to offer this production based onenvironmental protection and energy saving. In South Africa, HPWH has penetrated 16 percent of the market sharefor commercial water heaters.Because of the highly primary cost, it is difficult to become the alternative to the common water he

9、ater. However, ifwe can offer an air conditioner coupled with HPWH system, which can act as air conditioner and water heater withthe main components such as heat exchangers, compressor, four-way valve, and capillary tube, the primary cost willbe reduced and it can realize multifunction easily. In su

10、mmer, with the recovery of the waste heat of condensation, itcan offer “free” hot water, and also can improve the coefficient of performance (COP) of the air conditioner. Whenair conditioner is not required in spring and autumn, it can operate in HPWH mode. As the enhancement of the yearroundutiliza

11、tion, it can be more efficient and is expected to become a strategy solving the air conditioning and hotwater applications. Here we demonstrate an air conditioning water heater (ACWH) system, and the performanceanalysis is described in this article.1. THE PRINCIPLE OF ACWHThe schematic diagram of ai

12、r conditioning water heater system is shown in Figure 1. The system can offer thefollowing five operating modes. Mode 1 is only for heating water; mode 2 can act as space-cooling and waterheating;mode 3 can realize both space-heating and water-heating; the other two modes are the same with thecommon

13、 air-conditioning circles. The switching among all these modes is by means of on-off controls of thesolenoid valves and four-way valve. Each mode will be demonstrated as follows.1.1 Water Heating Mode2.1 Water Heating ModeThe system can operate in two heating modes. The one is direct heating water;

14、the other is heating water with waterrecycle in the adiabatic water tank. The controller can adjust the operating mode according to the water level sensorsin the tank. A water valve is placed at the hot water outlet which can be adjusted to control the water flow and keepthe condensing pressure cons

15、tant. When the tap water goes into the water-refrigerant heat exchanger (WRHE), itwill be heated to 50-55 directly within two minutes. If needed, the outlet water temperature can be set byadjusting the water valve.As shown in Figure 1, when the power is on, the compressor sucks low-pressure refriger

16、ant gas and then dischargeshigh-pressure gas into water-refrigerant heat exchanger (WRHE), where refrigerant is condensed and water is heateddirectly. After heat exchanges, the liquid refrigerant flows across four-way valve, then it is throttled to lowtemperatureand low-pressure liquid and gas by an

17、 electronic expansion valve. Refrigerant flows into outdoor aircooledcondenser where it is evaporated and becomes low-pressure gas. When the low-pressure gas returns to thecompressor, the circle begins again. In this mode, valve 1 is closed and valve 2 is open. When heating water, theoutdoor air-coo

18、led unit acts as evaporator, and the indoor fan doesnt run. The COPw is presented as a function ofpower Qw and the electric power W as shown in Equation (1).COPw=Qw / W=MCT (1)Where M is the mass flow of water; C is the specific heat of water;T is the water temperature difference betweenoutlet and i

19、nlet of the water-refrigerant heat exchanger (WRHE).1.2 Space-cooling and Water-heating (SCWH) ModeIn summer, with the recovery of condensing heat, the indoor air is cooled down at the same time. Compared withwater-heating mode, the high-temperature refrigerant is also condensed in the WRHE directly

20、, and then goesthrough the air-cooled condenser to be super-cooled where the outdoor fan doesnt run. It is throttled by capillary 1to low-temperature liquid and gas, and the indoor air exchanges heat with returned refrigerant. In this mode, valve 1is open and valve 2 is closed. This mode can act as

21、space cooling and water heating at the same time. However, it isnot necessary to recover the entire condensing heat which can be released in the air-cooled condenser. The totalcapacity is the sum of cooling capacity Qc and heating capacity Qw, and then total COPcw can be shown as theEquation (2).COP

22、cw=(QcQw)/W (2)2.3 Space-heating and Water-heating ModeRefrigerant flows across WRHE, evaporator, capillary 2, capillary1, and air-cooled condenser in turn. Space-heatingand Water-heating can realize in theory. This mode sometimes may not meet customers expectations, so that it mustoperate combined

23、with the water-heating mode and spacing-heating mode. If needed, an electric heater is available2.4 Space-cooling Mode and Space-heating ModeIn these two modes, refrigerant doesnt flow across WRHE or the water pump and inlet valve are closed, and thecondensing heat is completely released by the outd

24、oor or indoor heat exchanger. In fact, it is the same with a normalair conditioner, and is not described any more as above. In summer, space-cooling mode can be replaced by theSCWH mode, which can use the water-cooled and air-cooled heat exchangers at the same time. The performance ofthe system will

25、 be improved significantly with the enhancement of heat transfer.3. EXPERIMENTSExperimental research was performed at an air-enthalpy test laboratory which can also supply water with requiredtemperature and mass flow. The laboratory includes outdoor chamber, indoor chamber and control room. It consi

26、stsof insulated walls, air-handling equipments, temperature and humidity collection system, air volume testingequipment, electric control system and computer handling unit. The cooling and heating capacity can be tested byair-enthalpy test. Air handling equipments are provided in both test chambers

27、to control the dry bulb and wet bulbtemperatures, as well as humidity. The indoor unit of air conditioning was placed in one chamber; the outdoor unitand adiabatic storage tank were placed in another chamber. T-type thermocouples were placed at each temperaturetest point and pressures were tested by

28、 the pressure sensors. All the testing data can be collected and displayed bythe computer handling system.3.1 Prototype DesignThe prototype includes outdoor unit, indoor unit, and an adiabatic storage tank. Based on a common air conditioner,the system adds a water-refrigerant heater exchanger, a sto

29、rage tank, several solenoid valves, and water pump. The storage tank is an insulated cylinder and water capacity is about 800L. The prototype was designed based on theschematic diagram shown in Figure3.2 Experimental Test ConditionsIn mode 1, the ambient temperature was from -7 to 43, and the inflow

30、 water temperature was from 9 to 30.The outlet water temperature was set to 55 by adjusting the water valve. The other four modes operated only inthe nominal test conditions according to the national standards of air conditioner and heat pump water heater. Theexperimental test conditions are shown i

31、n Table4. RESULTSThis study emphasizes on the direct heating water. Mode 1 was tested in temperature conditions, while mode 2 justoperated in the standard testing condition shown in table 1. The prototype is different from a common heat pumpwater heater, which can offer hot water within 2 minutes by

32、 means of heattransfer of large temperature difference.The experimental results were discussed combined with the first two modes as follows.4.1 Hot Water OutputThe curves of hot water output are shown in Figure 2 at different inflow water and ambient temperatures. As shownin Figure 2, the hot water

33、output tends to rise more rapidly at higher ambient temperature or inflow watertemperature. It can offer about 400L hot water each hour when the inflow water temperature is 15 and ambienttemperature is 20. From this figure, we can know that the hot water output is relative to the parameters of theinflow