The air source heat pump water heater has been born in China for more than ten years. At present, there are more than 300 manufacturers in the air source heat pump water heater industry in China. In order to standardize the development of the industry, as early as April 2006, the General Administration of Quality, Technical Supervision, Inspection and Quarantine listed the heat pump water heater with a power greater than 24.36 kW / h in the catalogue of industrial product production license forensics, less than 24.36 kW / h is included in the CCC certification, which provides requirements for the industry access of the product and provides legal administrative basis. To ensure that the air source heat pump water heater can operate safely for a long time, it is necessary to analyze and study the maximum load condition of the unit. According to the standard simulation user use, when is the worst use of the unit, with this problem, we conduct research and experimentation. Because the compressor can be divided into fixed frequency machine and frequency conversion machine, the frequency conversion machine can be controlled according to the sensor and program in the unit. The actual input power of the compressor is controlled by the electronic control board. The maximum load condition is more complicated. For analysis, the following analysis and testing are carried out using a fixed frequency compressor as an example. 2 Standard study of maximum load conditions At present, there are two national standards for heat pump water heaters in China, namely GB/T 21362 - 2008 heat pump water heaters for commercial or industrial use and similar purposes, and GB/T 23137 - 2008 household and similar heat pump water heaters. These two standards have basically covered the heat pump water heater products in the existing market. The two standards have basically the same definition and working conditions for air source heat pump water heaters. 2. 1 Comparison of maximum load conditions parameters The maximum load conditions are as follows: (1) The maximum load conditions for domestic and primary heated commercial air source heat pump hot water machines are water side: inlet temperature 29, outlet temperature, air side: dry bulb temperature 43, wet bulb temperature 26GB / T213622008 air source heat pump hot water machine test condition project use test (or hot water side) initial water temperature termination water temperature heat source side (air side) dry bulb temperature wet bulb temperature heat pump nominal condition maximum load industrial type 15 55 20 15 low temperature type 9 55 7 6 common type 29 55 43 26 low temperature type 29 55 38 23 air source heat pump hot water machine maximum load condition table type one heating type household commercial cycle heating type household commercial common type commercial low temperature type water side Inlet water temperature / initial water temperature Outlet water temperature / Termination water temperature 29 55 Air side dry bulb temperature Wet bulb temperature 43 38 26 23 ( 2) Circulating heating commercial ordinary air source heat pump hot water machine maximum load condition is initial water temperature 29, the water temperature is terminated 55, while the air side is: dry bulb temperature, wet bulb temperature 26. (3) The maximum load condition of the circulating heating commercial low temperature air source heat pump water heater is the initial water temperature 29, the termination water temperature 55, and the air side is: dry bulb temperature 38, wet bulb temperature 23. 2. 2 Comparison of maximum input power under maximum load conditions According to the standard test conditions and the calculation method in the standard, the three maximum load conditions are obtained: (1) Household and primary heated commercial air source heat pump water heaters under their maximum load conditions, due to their evaporator side and condensation The working condition of the device side is certain, and the parameters such as evaporation temperature, condensation temperature, evaporation pressure and condensing pressure in the unit are basically stable, so the unit power is also stable. After the test is stabilized, its maximum power should be stable within a certain range. (2) The circulating heating commercial air source heat pump hot water machine has no change in the air side dry and wet bulb temperature under its maximum load condition, but the input power of the unit is also increasing due to the continuous increase of the water tank temperature. 3 standard test verification 3. 1 Household and primary heated commercial air source heat pump water heater The 380V 3N 50Hz air source heat pump water heater with a heating type KQR - 16S produced by a factory was tested as an example, and the test data was obtained. 3. 2 circulating heating commercial ordinary air source heat pump water heater The circulating heating type commercial common model produced by a factory is: KFXRS- 17II 380V 3N 50H z air source heat pump hot water machine as an example to test, get time? Enter the power curve as shown in the test data. 3. 3 circulating heating commercial low temperature air source heat pump water heater The circulating heating commercial common model produced by a factory is: DKFXRS-17II 380V 3N 50H z air source heat pump water heater as an example, the test data is shown. 4 Conclusion (1) Household and primary heated commercial air source heat pump water heaters have stable input power to the unit under maximum load conditions. (2) Under the maximum load condition of the circulating heating commercial air source heat pump water heater, the input power of the unit increases continuously with the water temperature of the water tank. It is not difficult to find that the circulating heating commercial air source heat pump water heater can calculate the power consumption of the unit under the maximum load condition and the test according to GB/T21362-2008 Appendix B. The final state input power has a large deviation, which is caused by the formula of B3.1. Analysis B3. 1 Formula E = N 0 /H (E is the power consumption of the unit, N 0 is the total power consumption of the heat pump water heater for one cycle), it can be seen that E is the average value of an integral, so the calculated The power consumption is lower than the final input power. It is not difficult to understand that the worst case of the maximum load condition is when the unit is in the unit of heat equal to the tank being stabilized in the water and running continuously, that is, the air side dry and wet bulb temperature of the unit is constant, and the water side circulation flow is constant. Appears during steady operation under effluent temperature conditions. Therefore, enterprises should pay attention to this point when designing this type of unit and marking the maximum input power in the nameplate. 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Discussion on the Maximum Load of Air Source of Constant Frequency Compressor
1 Air source heat pump water heater is a new generation of hot water production equipment after boilers, gas water heaters, electric water heaters and solar water heaters. Air source heat pump water heaters are quickly recognized by consumers in the market for their high efficiency, energy saving, environmental protection, safety, comfort, and convenient installation, and have developed into an energy-saving and environmentally-friendly emerging industry.