Weak current College】 【household air-conditioning refrigerant charge calculation.

<br> Each air conditioners design there how can I determine the refrigerant charge, particularly in the capillary for throttling device of air conditioners, due to capillary control capability with thermostatic expansion valve, charge of change on its performance. Current research in this field, .the lack of mature theoretical calculation method, the manufacturers had to take the test, an estimate based on the experience of more than one test, in order to finalize the best charge. The repetition of work is not only costly and time consuming. In order .to determine the best injection quantity so simple, this steady performance simulation system, based on the best split-type air conditioners for the calculation of the charge and determine system best charge principle: when the air conditioner's structure size and working conditions, cooling capacity meet .the design requirements, the system of maximum-efficiency ratio. At this point, air conditioner and all parts in top working condition. I have divided the KFR-32GW / H cross type air conditioner test repeatedly, calculation and test results are. <br .> 1. charge calculation <br> Refrigerant in the refrigeration system state can be divided into single phase and phase two, the two parts of the refrigerant mass calculation should be considered. <br> 1.1 single-phase district quality calculation <br> Single .-phase district refrigerant density computing simpler, in a single area of all parts of the refrigerant through the integral calculation. <br> 1.2 two-phase district quality calculation <br> Charge calculation of difficulty in two-phase area of refrigerant, the key .is a two-phase district cavitating coefficient calculation. In a two-phase cavitation coefficient fixed area model and the validation context, many scholars have already done a lot of work. <br> 2. charge on the effect and the performance of test results .<br> Different refrigerant charge performance of the air conditioner is not the same. I divided the KFR-32GW / H cross-type air conditioners in different charge under calculation and experiment. <br> Test conditions: outdoor temperature: 35 ± 0.5 ℃ .; wet bulb temperature: 19.5 ± 0.3 ° c; the temperature in the ball room: 27 ± 0.5 ℃; capillary specifications: length 450mm \ diameter X1.4mm. <br> In order to verify the model, the parameter changes, the determination .of the air conditioner's steady-state parameter. With the steady state calculation results layout along the refrigerant flow direction by 14 on thermocouple and two pressure gauges measure the various parts of the import and export parameters. <br> Refrigerant charge determination using electronic scale, .up to its range, the accuracy of ± 6kg 2g. Add liquid seperator and refrigerant cylinders with plastic hose connection, when the tube is measured for gas. <br> With the increased charge quantity: <br> ① condensing and evaporation pressure is increased .; <br> ② compressor suction temperature lower, when the drop to the evaporator outlet as saturated or two-phase State compressor suction temperature stopped declining. When the refrigerant charge to 690g, evaporator outlet no superheat, evaporator with maximum efficiency; <br> .③ as the compressor suction temperature drop, compression ratio changes, the exhaust temperatures drop in the compressor, which is conducive to the compressor working stability; <br> ④ in 690g following, with charge of increased cooling capacity increase quickly, and when greater than .690g, cooling capacity increase. This is mainly due to charge up to 740g, evaporator outlet for two-phase zone, chill-out is not full, but the compressor input power as the charge increases. Energy efficiency ratio of the peak there is a .clear, that is, when the 690g maximum-efficiency ratio; and when a charge or is less than this value, the energy efficiency ratio are declining, largely due to charge lower evaporator outlet for superheat is large, heat transfer area does not take full .advantage of the cooling capacity, therefore, decline is large, this compressor input power reduction. When the charge is large, the evaporator outlet for two-phase zone, chill-out is not full, the input power increase, cooling capacity changes not obvious ., therefore energy efficiency than the down. <br> Test and calculation showed that at best charge near the air conditioner's maximum-efficiency ratio and higher cooling capacity. At this point the evaporator outlet basic to saturation, area. In actual, the condenser outlet .not measured undercooling, this is because the process structure and measuring instrument accuracy on the reasons, in which case the condenser heat transfer area has also been fully utilized. <br> Theoretical calculation of optimal charge for actual value 685g, and very close to each .other. <br> 3, the impact of the system's total charge quantity factors <br> 3.1 refrigerant flow total internal <br> Generally, the larger the accumulated flow content, the refrigerant charge should also be more. System fluid pipe length on the .total charge for greater impact. <br> 3.2 device running the condition <br> When the air conditioner operation changes the operating mode, it may require system charge different. <br> 3.3 capillary dimensions <br> Capillary length-to-system best .charge having an effect, different capillary length will change the amount of refrigerant circulation and air conditioner in the Department of State. By calculating and specimen KFR-32GW / H at the cross test, when air conditioners-capillary length increased to 450mm, best refrigerant .charge to 690g. <br> 3.4 lubricant quantity <br> Refrigerants in the lubricating oil is solubility, solubility of oil in the refrigerant quantity as the temperature and the oil mass, thus determining the total charge should consider this part of the amount of the .refrigerant. <br> 4. conclusions <br> ① This article adopts Hughmark model calculation conditioner two-phase refrigerant volume area is feasible, it is the whole charge calculation of the key. <br> ② When cooling capacity to meet the requirement, .to the maximum-efficiency ratio to determine the best charge air conditioners is feasible. <br> <br> <br>.