Constant temperature and humidity test chamber compressor power consumption - Database & Sql Blog Articles

Original source: constant temperature and humidity test chamber compressor power consumption editing: Lin frequency instrument

The medium temperature refrigerant used in the single-stage refrigeration cycle in the constant temperature and humidity test chamber is R404A. The evaporation temperature is -46.5 °C (R22/-40.7 °C) at one atmosphere, but the heat transfer temperature difference of the air-cooled condenser is usually taken. Around 10 °C (in the forced air cooling cycle, the temperature difference between the evaporator and the inner box), that is, the box can only produce a low temperature of -36.5 ° C, of ​​course, by lowering the evaporation pressure of the compressor, R404A can be cooled The minimum evaporation temperature of the agent is reduced to -50 ° C; therefore, to obtain a low temperature of -50 ° C and below, it is necessary to use a medium-temperature refrigerant and a low-temperature refrigerant cascade refrigeration cycle to obtain a low temperature of -50 ° C to -80 ° C, Low temperature refrigerant is generally selected R23, its evaporation temperature is -81.7 ° C under one atmosphere.

The minimum evaporation temperature of a single-stage vapor compression refrigerator in a constant temperature and humidity test chamber depends mainly on its condensing pressure and compression ratio. The condensing pressure of the refrigerant is determined by the type of refrigerant and the temperature of the environmental medium (such as air or water). Under normal circumstances, it is in the range of 0.7~1.8Mpa. The compression ratio is related to the condensing pressure and the evaporation pressure. When the condensing pressure is constant, as the evaporation temperature decreases, the evaporation pressure also decreases accordingly, thus increasing the compression ratio. It will cause the temperature of the exhaust gas of the compressor to rise, the lubricating oil will become thinner, and the lubrication condition will be deteriorated. In severe cases, even carbonation and cylinder pulling will occur. On the other hand, the increase of the compression ratio will lead to the gas transmission of the compressor. The coefficient is reduced, the cooling capacity is reduced, and the actual compression process deviates from the isentropic process. The compressor power consumption increases, the refrigeration coefficient decreases, and the economy decreases.

The constant temperature and humidity test chamber is suitable for instrumentation materials, electrical, electronic products, household appliances, automobile and motorcycle parts, chemical coatings, various electronic components and other related products in high temperature, low temperature, humidity environment, storage, transportation, Adaptability test at the time of use. This test equipment is mainly used for environmental simulation test of the physical and other related characteristics of the product under the conditions of low temperature and high temperature according to the requirements of national standards or user-defined requirements. After the test, the test is passed. To determine the performance of the product, whether it can still meet the predetermined requirements, in order to facilitate product design, improvement, identification and factory inspection.

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