【 Weak current College 】 refrigeration equipment debugging and running parameters analysis---Power By 【 China power house network 】

Refrigeration equipment debugging is device running parameter adjustment to the desired range. The parameters of the refrigeration appliance running: evaporating temperature and evaporation pressure; condensing temperature and condensing pressure; compressor suction and discharge temperature and suction and exhaust pressure; throttle refrigerant liquid temperature before; two levels of compression refrigeration system of intermediate pressure, etc. These operating parameters is not fixed, but with the external conditions (such as the cooling water temperature, cooling object cooling load) changes. Therefore, when you debug in refrigeration equipment, must be based on the external conditions and characteristics of various operating parameters, adjusted so that they are reasonable, affordable and safe running of the value.
　　
A) evaporation temperature and evaporation pressure
　　
Evaporation temperature and evaporation pressure is determined based on the user's requirements. Device running evaporating temperature, according to the temperature of the cooling medium and work characteristics to determine. Adjust the evaporating temperature, actually adjust evaporation temperature and cooling medium temperature difference between the values. From the perspective of heat transfer, thermal heat transfer made big, its effect is good, cool down quickly. But increased heat temperature, evaporation temperature decreasing. The compressor refrigeration capacity, when some condensing temperature, evaporation, the lower the temperature, the smaller its cooling capacity, due to insufficient cooling capacity, which is the giant of the cooling medium temperature drop down. While smaller temperature difference, the heat effects, compressor cooling capacity while increasing, but the evaporator heat is not sufficient. Therefore, we should be based on different forms of refrigeration equipment, reasonable choice of temperature difference.
　　
According to JB/T4329-97 volumetric water (heat pump) unit standard requirements of the condition of water chiller for cooling water inlet water temperature is 12 ° c, temperature 7 ° c, the export of the cooling water inlet water temperature 30 ° c to 35 ° c water temperature for export. So the chiller in the factory, automatic control and protection components of value, will enable the chiller in nominal condition of the running state. Due to the increase of water temperature on the cold water unit economics very favorable. Run, to meet the air conditioning use requirements, maximize cooling water temperature. If the actual use of the unit's long-running cold water outlet temperature is 7 ° c, when ordering the contract should indicate the need for cooling water temperature requirements. Therefore, the actual operation of the unit, according to the specific requirements of air conditioning object, you can apply the cold water outlet temperature increase or decrease as appropriate. In General, the temperature is cold water evaporation from water temperature low 2 ~ 4 ° c, the control of evaporating temperature in 3 to 5 ° c range. For cooling liquids of evaporator, its evaporation temperature should be cooling liquid temperature low 4 ~ 6 ℃.
　　
Adjust the evaporation temperature and cooling medium temperature difference, really, the throttle valve hole opening.
　　
There are now commonly used to throttle, manual choke valve, thermostatic expansion valve and constant expansion valves, ball valves, etc. We in the debug runtime, mainly by observing changes in evaporation pressure to determine the expansion valve to open degree is moderate. If the valve is open through small, inadequate for liquid, vapor pressure and evaporation temperature drops, the compressor suction superheat, exhaust temperature also increases; and for the amount of excess, the evaporation pressure and temperature is rising, the evaporation of excess liquid, also makes densener accident. So correctly control throttle opening is run in regulation the evaporation temperature and evaporation pressure of one of the main method. In addition, when the cooling load and compressor capacity, if the evaporator heat area design is too small or the internal and external surface dirt, then make the temperature decreased; such as excessive heat exchange surface, the evaporation temperature rise; if the cooling load and evaporator heat area are unchanged, the compressor capacity increase, the evaporation pressure and temperature reduction, capacity decreases, the evaporation temperature and pressure.
　　
B) condensing temperature and condensing pressure
　　
Refrigeration systems for condensing pressure to high pressure in the table indicates the pressure, absolute pressure, check the refrigerant thermodynamic properties of table-related. In General, the condensing temperature than cooling water inlet temperature 5-7 ° c higher than forced ventilation cooling air inlet temperature: 10 ~ 15 degrees centigrade. When evaporation temperature does not change, the condensation temperature, condensing pressure also increases the compression, the compressor, gas coefficient decreases, the compressor refrigeration capacity and power consumption reduction, increased. In addition, the condensing pressure, compression and exhaust temperatures to rise. If the exhaust temperature is too high, then the compressor lubricating oil lubrication thinned, impact, when the exhaust temperature and lubricating point close to the door, you will make some Lube carbonization and accumulate on the effect of exhaust valve, the valve sealing performance, in addition, the valve plate, cover with spring, etc.
　　
Condensing temperature is too high, from the design perspective because condensation area is too small. At this point, you cannot shut down the compressor discharge one condenser thermal steam condensing all, and only for liquid at high pressure and temperature condensation. In this case, increase the size or reduce the condenser in parallel number of compressor operation.
　　
Running, condenser surface oil film, scale or system have a small amount of air and other Non-Condensable gases that can be increasing the heat transfer resistance, enabling timely refrigerant vapour condensation. Usually approach is regularly put on oil, air and water quality situation periodically clear scale.
　　
Lower condensing temperatures on the operation of the refrigeration unit; its measures have two aspects: one is to reduce the condenser cooling water inlet temperature; 2 increase the cooling water. But cooling water temperature depends on the atmospheric temperature and relative humidity, the effects of changes in natural conditions and restrictions; and increase the cooling water is easy, but increase the cooling water flow, caused by the cooling water pump power consumption increased, excessive velocity also aggravate water wear should be fully taken into account.
　　
In addition, the cooling water is open-cycle system, cooling tower in the atmosphere. Dust, debris and corrosive gases in the atmosphere and harmful substances are dissolved in water, causing oxidation under the Sun, and reproduction of microorganisms in water, cooling water systems work in serious harm. As a result ofThis provision, the relevant practice for the cooling water system and condenser pipes must be thoroughly cleaned every year to ensure the normal work performance condenser.
　　
C) compressor suction temperature
　　
Compressor suction temperature, positive displacement compressors, is the compressor suction chamber temperature of the refrigerant gas in. Breathe in the high temperature, high discharge temperature, the refrigerant is inhalation, than rongda compressor unit volume small refrigeration quantity; on the contrary, the compressor suction temperature is low, the unit volume cooling capacity. But the compressor suction temperature too low can cause the inhalation of liquid refrigerant is compressor, so that the reciprocating densener phenomenon.
　　
In addition, the compressor suction pipe length and bandaging of insulation performance is good or bad, the size of the superheat, also has a certain influence. Suction temperature control in the refrigeration appliance suction superheat is 5 ~ 10 ° c, the regenerative heat exchanger of freon system suction superheat is 15 ° c is quite appropriate. Therefore the machine running the operation, it should be noted that the compressor suction temperature control, usually with adjustable thermostatic expansion valve adjustment screw to adjust the size of the TSC.
　　
D) compressor discharge temperature
　　
Compressor discharge temperature is refrigerant compressed after the high-pressure overheated steam. Due to the emission of refrigerant compressors for hot steam, its pressure and temperature corresponding relations between does not exist. Compressor discharge temperature can be obtained from the exhaust pipe at the thermometer readout.
　　
Exhaust pressure usually slightly higher than the condensing pressure and the condensing temperature exhaust temperature is much higher. Exhaust temperature and type of the refrigerant, main and suction temperature, pressure and pressure ratio, and as they grow and improve. Condensing temperature and exhaust temperature is too high on the compressor running are negative and should be prevented.