The working medium circulating in the refrigerated cold […]
The working medium circulating in the refrigerated cold room is called refrigerant. When the refrigerant passes through the evaporator, it draws heat from the object to be cooled, and then discharges the heat to the atmosphere (environment) through the condenser through the cooling water. Ammonia (R717) is used as a refrigerant. When water is present, ammonia corrodes copper and its alloys (except tin bronze), and presents an explosion hazard when mixed with air (explosion concentration is 16-25% by volume) Special attention should be paid during operation. For other properties, please refer to the relevant information. Freon (R22) as a refrigerant, due to the refrigeration system should pay attention to the oil return, to ensure that the refrigeration system is dry and does not leak.
Freon refrigerant described in this note specifically refers to the R22 working medium, the following will not be described. Refrigerant saturation state, the pressure and temperature between the corresponding relationship, that is, a certain pressure, the temperature is also certain, if you know the condensing pressure (exhaust pressure), evaporation pressure (suction pressure), you can from ammonia or freon heat The nature of the table to find the corresponding condensation temperature and evaporation temperature.
Frozen oil quality is good and bad direct impact on parts wear and compressor life, it must choose high-quality frozen oil. For ammonia or Freon refrigerants should be used as specified in the compressor oil. When not available reference to the use of ZBF34003-86 "frozen oil" No. 46 freezer oil. Not allowed to use animal oils, vegetable oils and animal and vegetable oils mixed in use, if the viscosity decreased by 15%, the color of the oil becomes dark, in order to prevent carbon deposition should be promptly replaced with new oil.
Exhaust pressure and condensing pressure are approximately the same, (in fact, due to slight differences in pipeline loss, the general design conditions of pressure loss of 0.01MPa) both and the cooling water temperature, water and condensation area, exhaust pressure (condensation Pressure) With the cooling water temperature decreases, cooling water volume increases and decreases; otherwise it rises. Exhaust pressure increases, not only the exhaust temperature and lower cooling capacity, increasing power consumption, so in operation should minimize exhaust pressure (condensing pressure). When the water temperature is constant, in order to reduce the exhaust pressure to increase the amount of water consumed by the power, a lot of increase, it is not necessarily economical, both should be considered.