Why is throttling valve not replaced by an isentropic turbine in the ideal Vapour compression refrigeration cycle?
Why is the throttling value not replaced by an isentropic turbine in the ideal vapour compression refrigeration cycle? Because the feed is a liquid and the effluent is fairly low quality, the average specific volume of the working fluid in the turbine is very small. the turbine will produce very little work.
How is the throttling process in Vapour compression refrigeration cycle carried out?
When the refrigerant enters the throttling valve, it expands and releases pressure. Consequently, the temperature drops at this stage. Because of these changes, the refrigerant leaves the throttle valve as a liquid vapor mixture, typically in proportions of around 75 % and 25 % respectively.
Why turbine is not used in place of expansion valve?
Expansion valve has diaphragm and sensing element or power element where it sensed load and according to that diaphragm functions and controlled flow of liquid refrigerant to freezer. turbines can not handle variable load conditions .
Why are Vapour absorption system better than compression system?
Vapor compression system does not work well at partial load. The performance is very poor. In vapor absorption system, if the liquid refrigerant leaves the evaporator, the refrigerating effect is reduced but the system functions well without any problem.
What is superheat in HVAC?
“Superheat is a measured value,” Tomczyk said. “It is the difference between two temperatures. Superheat is measured as the difference between the actual temperature of refrigerant vapor at a certain point and the saturation temperature of the refrigerant.
What happens if superheat is too high?
Too high of a superheat can cause the heat of compression to increase, causing the temperature at the discharge valves to increase. If the temperature increases beyond its safe operating temperature, it will cause damage to the compressor.
How much superheat should I have?
Superheat for most systems should be approximately 10F measured at the evaporator; 20F to 25F near the compressor. If the suction pressure is 45 psi, (which converts to 22F) and the suction temp is 32F, the system still has 10F of superheat.