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A condensing temperature
There is the pressure of the refrigerant condensed in the condenser the gas is condensed into fluid pressure, the pressure inside the condenser refrigeration system can not be measured, in fact, the refrigerant in the exhaust pipe and the pressure drop in the condenser is actually very small, so no matter which design debug or maintenance, is generally believed that the exhaust gas pressure is approximately equal to the condensing pressure.
Condensation temperature and condensation pressure correspondence, i.e., the saturation temperature at condensation, the condensation temperature is not equal to the temperature of the cooling medium, there are heat transfer temperature difference between the two.
So, how to determine the condensing temperature?
According to experience condensing temperature, the system temperature = + (10 ~ 15 ℃); We conditioned summer ambient temperature of 35 ℃ examples.
The air-conditioning in summer outdoor temperature of about 35 degrees, at this time we can estimate the condensation temperature: condensation temperature = 35 + (10 ~ 15 ℃) = 45 ℃.
Condensation temperature corresponding to the condensation pressure is the pressure (the refrigerant temperature may be provided by a number of public gauge query words) if the discharge pressure of the refrigeration system if the pressure is lower than this, the amount of charge of refrigerant consider whether less than normal and the like;
Filling amount of exhaust gas pressure in the system if pressure is higher than this, consider whether the high side of the refrigerant, the adequacy of the condenser heat exchanger, the expansion valve opening degree is too small and the like.
Second, the evaporation temperature
Evaporating temperature is the temperature at which the liquid refrigerant boils. When the refrigerant flow rate constant, the lower the vapor pressure, the lower the evaporation temperature. However, continued reduction in the evaporation temperature of the system, the cooling capacity of the refrigeration compressor will continue to decrease, the cooling speed is not necessarily faster, but also at the low evaporation temperatures, lower coefficients refrigeration system .
So, how to determine the evaporation system pressure is normal?
According to experience evaporation temperature, ambient temperature = air-conditioning system - (10 ~ 15 ℃); our summer (set room temperature in 22 ℃) air conditioner as an example:
Summer air conditioning indoor unit temperature is 22 degrees, at this time we can estimate the evaporation temperature: evaporation temperature = ambient temperature - (10 ~ 15 ℃); i.e., the evaporation temperature = 22- (10 ~ 15 ℃) ≈12 ℃;
Evaporation temperature corresponding to the evaporation pressure is the pressure, (the refrigerant temperature may be provided by the public Encyclopedia query gauge number), if the evaporation pressure of the refrigerant is lower than the system pressure, consider whether there is a heat exchanger of the evaporator problem, the expansion valve whether the next degree too.
If the evaporation pressure of the system pressure is higher than this, consider the amount of charge consider whether the high side of the refrigerant, the expansion valve opening degree is too large and the like.
Third, the intake air temperature
It refers to the compressor suction temperature at the suction valve or the temperature of the compressed refrigerant into the buckle at. To ensure the safe operation of the compressor, to prevent liquid hammer phenomenon punch cylinder, intake temperature slightly higher than the required number of evaporation temperature, i.e. the refrigerant vapor becomes superheated gas.
Intake air temperature is normal, may be fed directly to the expansion valve opening degree is proper. Many people know that the suction superheat degree, the suction superheat know most preferably 5 ~ 7 ℃;
But many newcomers do not know the real meaning of existence this parameter; suction superheat know, we can calculate the system's normal intake air temperature.
Intake air temperature = + Suction superheat evaporation temperature, such as:
We know that the evaporation temperature is a refrigeration system 12 ℃; The optimum suction superheat is 5 ~ 7 ℃; In this case we can calculate the optimal temperature of the intake system is about 17 ℃;
We can feel the temperature, to determine at this time of the intake air temperature is normal. For example the touch than 17 ℃ intake pipe to the ice, we can determine the opening degree of the expansion valve at this time or a large amount of refrigerant charge; if intake temperature than 17 ℃ to hot, the expansion valve can be determined at this time the smaller the opening degree of the refrigerant or the filling less.
If no condensation intake pipe, intake air temperature is too high the description, check the refrigerant filling amount is less a small opening or expansion of the valve. If the intake pipe frost (ice), described a low intake temperature, check the amount of refrigerant charge or whether multiple expansion valve opening degree is large.
Fourth, the exhaust gas temperature
Exhaust gas temperature is the temperature of the exhaust gas of the compressor for power, the available temperature measurement obtained from the exhaust pipe. Level and pressure ratio and exhaust gas temperature proportional to the temperature of intake air. The pressure ratio, the higher the intake air temperature, the higher the exhaust gas temperature
Many peers have not heard the term "exhaust gas superheat", "exhaust superheat": compressor discharge pipe (or a condenser inlet temperature) difference between the saturation temperature corresponding to the condensation pressure.
A normal discharge superheat of the refrigeration system 20 ~ 30 ℃. Therefore, we can experience this value to determine whether the normal exhaust gas temperature; for example: a condensing temperature of 45 ℃ air conditioner, the exhaust gas temperature at this time is normal should be:
The temperature of the exhaust gas discharge superheat = + condensing temperature = 25 + 45 = 70 ℃;
6.3.5 Operating current
Running current compressor There are many factors, such as:
Poor heat dissipation outside the machine;
External supply voltage abnormality;
Air cooling system;
Poor oil return, resulting in high shell / internal temperature;
Impurities in the system, too much water,
In addition, we talk about the impact of the refrigerant and the compression ratio and the current:
How many compressed refrigerant
The degree of refrigerant compression (compression ratio)
It is actually very good understanding, for the first: the more compressed refrigerant compressor, the compressor is the harder it is compressed, the current also big. The second respect: the higher the degree of compression of the refrigerant (compression ratio increases), the more work the compressor, the corresponding current is large.
Therefore, the operating current of the compressor, to a large extent reflect the amount of refrigerant charge cooling system is normal. Usually a current value on the nameplate number of refrigeration equipment.