What is the effect of pressure and temperature on the refrigeration system?

refrigeration system has failed, generally through watching, listening, touch to understand the operating state of the systemWhen the operating pressure and temperature of the system exceed the normal range, in addition to indoor and external environmental temperature deterioration, there will be problems, which is an important basis for determining the root cause of the fault, the refrigeration system pressure and temperature detectionthe pressure of refrigeration system: refrigeration system in operation can be divided into high, low pressure two partsThe high-pressure segment is called high pressure from the exhaust port of the compressor to the throttle valveThe suction port pressure of the compressor is called the suction pressure, the suction pressure is close to the evaporation pressure, the difference between the two is the flow resistance of the pipelinefor convenience, the evaporation pressure and condensation pressure of the refrigeration system are detected at the suction and exhaust ports of the compressorThat is, commonly referred to as the suction and exhaust pressure of the compressorThe purpose of detecting the suction and exhaust pressure of the refrigeration system is to obtain the evaporation temperature and condensation temperature of the refrigeration system, so as to obtain the operation of the refrigeration systemthe temperature in the refrigeration system: the temperature in the refrigeration system covers a wide range of areas, such as evaporation temperature, suction temperature, condensation temperature, exhaust temperature, etcThe evaporation temperature and condensation temperature are the determining effect sits on the operating conditions of the refrigeration system.evaporation temperature: refers to the temperature at which the liquid refrigerant boils gasification in the evaporatorExample: the evaporation temperature of the air-conditioning unit is 5 to 7 degrees as the evaporation temperature of the air-conditioning unit zuijia, that is to say, the air-conditioning unit design evaporation temperature is between 5 and 7 degrees, when the air-conditioning unit after maintenance in commissioning, if the evaporation temperature can not reach 5 to 7 degrees, should find out the reasonand evaporation temperature can not be directly detected, only by detecting the corresponding evaporation pressure to obtain its evaporation temperature, by consulting the refrigerant saturation temperature pressure control tablecondensation temperature: the temperature at which the refrigerant's superheated vapor condenses into a liquid after heating in the condenserThe condensation temperature can not be directly detected, only by detecting its corresponding condensing pressure, and then by consulting the refrigerant saturation temperature pressure control tableThe condensing temperature is high, the condensing pressure is relatively high, they correspond to each other Condensation temperature is very high, the unit load is heavy, the motor overload, the operation is not favorable, its cooling capacity correspondingly decreases, the power consumption increases, should be avoided. exhaust temperature: refers to the temperature of the compressor exhaust port (including the temperature at which the exhaust port takes over) Detection of exhaust temperature must have a temperature measurement device, the general small machine is not set up, temporary measurement can be used semiconductor point thermometer detection, but the error is larger The exhaust temperature is affected by the suction temperature and condensation temperature, the suction temperature or condensation temperature increases, and the exhaust temperature increases accordingly, so the suction temperature and condensation temperature must be controlled in order to stabilize the exhaust temperature. inhale temperature: refers to the temperature of the gas that the compressor inhales the connecting tube Detection of suction temperature needs to have a temperature measurement device, the general small unit does not set up a temperature measurement device, maintenance and commissioning generally with the hand touch estimation, air-conditioning unit suction temperature generally requires control of 15 degrees for about Exceeding this value has some effect on the cooling effect II, the effect of the change of suction pressure refrigeration system the factors of low suction pressure: the suction pressure is lower than normal, the factors are insufficient cooling capacity, cold load is small, expansion valve opening is small, condensation pressure is low (refers to the capillary system), and the filter is not smooth. factors with high suction pressure: the suction pressure is higher than normal, the factors are excessive refrigerant, large refrigeration load, large expansion valve opening, high condensation pressure (capillary system) and poor compressor efficiency , the impact of exhaust (condensation) pressure changes on the refrigeration system the factors of high exhaust pressure: when the exhaust pressure is higher than normal, there is generally a low flow of cooling medium or high temperature of the cooling medium, excessive refrigerant charge, large cold load and expansion opening. low exhaust pressure factors: the exhaust pressure is lower than normal, the factors are low compressor efficiency, insufficient refrigerant volume, cold load is small, expansion valve opening is small, filter is not smooth, including expansion valve filter and low temperature of cooling media. four, the relationship between the suction temperature and the exhaust temperature
in fact, the exhaust temperature of the system is closely related to the suction temperature As the suction temperature increases, the exhaust temperature is relatively higher, and the reverse is lower By figuring out their relationship, you can master and control them well, making the refrigeration system work better. five, compression condensing unit about the temperature changes on the refrigeration system the impact of exhaust temperature: summer situation, the compressor exhaust temperature is relatively high, hands can not touch According to national standards, the exhaust temperature of the R22 refrigeration system should not exceed 150 degrees, which is abnormal the exhaust temperature is very high: is the compressor's inhale temperature is very high, or condensation temperature is too high caused, must be noted The exhaust temperature is too low, the hand touch exhaust pipe is not hand, which indicates that the suction temperature is particularly low, the compressor may be wet travel operation or the system is quite low operating Compressor wet travel is easy to damage the valve structure, refrigerant operation is very small, will affect the motor winding heat, accelerate the aging of insulation material. the effects and causes of the high temperature of the enclosure: the surface temperature of the case exceeds the normal range, mainly the suction temperature of the refrigeration system is over (above 15 degrees) Too high hot steam into the compressor, absorb the heat inside the case, so that the temperature of the vapor is higher, so that the temperature of the case increases The temperature of the superheated vapor rises very high, the temperature of the machine case also rises very high, is not conducive to the cooling of the oil, which will affect the lubrication of moving parts, accelerate wear, serious so that the bearing holding shaft (bite to death) It also causes the exhaust temperature to rise. the effect and cause of the low temperature of the case: the surface temperature of the case is lower than the normal range, the reason is that the suction temperature is too low (less than 15 degrees) It is beneficial for the cooling of both the frozen oil and the motor winding, but the cooling capacity decreases When the suction temperature is particularly low, will make most of the machine shell exposed, there is a risk of liquid attack, this is a fatal blow to the compressor, should pay special attention At the same time, a large amount of refrigerant is dissolved in the frozen oil, which is not conducive to the lubrication of moving parts. the temperature of the capillary tube: under normal circumstances, the capillary tube is cool and dewy, there is a liquid flowing sound Unusual: 1, the surface is very cold and dew, but the flow sound is louder, the reason is insufficient refrigerant, 2, the surface is not cool, not exposed, can not hear the flow of sound, the reason is filter blocking or capillary blocking. the temperature of the evaporator: under normal circumstances, the outer surface of the evaporator is very cold, its dew drops continue to drip down, in and out of the wind temperature is larger, usually at 12 to 14 degrees, abnormal situation, evaporator surface is not too cold, dew is not much, or not dew, you can hear the refrigerant flow sound is very loud, in and out of the wind temperature difference is small This is due to insufficient refrigerant, or low opening of the expansion valve the environmental temperature requirements of outdoor units: According to national standards, outdoor units in the ambient temperature of 35 degrees below the temperature, air-conditioning units should ensure normal operation, and can achieve the product nameplate of the refrigeration capacity and other indicators When the ambient temperature in the range of 35 to 43 degrees, air conditioning units can run, but can not guarantee its mimgpai standard refrigeration capacity, it has been at full load operation, this is the condensing temperature, pressure, exhaust temperature are quite high, if the indoor machine heat is larger, the electronic control protector may move, cut off the power supply, stop operation When the outdoor temperature exceeds 43 degrees, the air-conditioning unit is in overload operation, which will cause the action of the electronic control device, cut off the power supply, stop the operation. the requirements of indoor air-conditioning temperature: indoor normal temperature value zui high should not exceed 30 degrees as well If the temperature of more than 30 degrees, the air-conditioning unit may be in the operation of overload conditions, the condensing temperature of the refrigeration system and exhaust temperature will rise, may also lead to electrical protector action, cut off the power supply, the operation of the air-conditioning unit is not conducive to the operation of the unit.