Question 180Refrigeration/AC - Assistant Engineer70% to pass
The thermostatic expansion valve in a refrigeration system further opens when the diaphragm flexes downward. With all other conditions being the same, what single condition causes this?
AI Explanation
The correct answer is C) an increase in sensing bulb temperature.
The thermostatic expansion valve in a refrigeration system functions to maintain a constant superheat at the outlet of the evaporator. When the sensing bulb temperature increases, the pressure in the sensing bulb also increases, causing the diaphragm to flex downward. This opens the valve further, allowing more refrigerant to flow into the evaporator, which in turn increases the evaporator pressure. The other options, such as an increase in evaporator pressure (A) or an increase in the superheat setting (D), would have the opposite effect on the valve's opening.
Related Questions
#178 When the sensing bulb of a thermostatic expansion valve is charged with a fluid different from the charge used in the system, what name of the charge is associated with the power element? #179 Through which of the components shown in the illustration is flash gas formation a normal occurrence? Illustration GS-RA-25 #181 A typical shipboard domestic multi-box refrigeration system operates with one compressor and condenser. What is the purpose of the sensing line connected to the thermal bulb at the evaporator coil outlet? #182 Which of the following illustrated expansion valves is designed to maintain a constant evaporator pressure rather than a constant evaporator superheat? Illustration GS-RA-24 #183 Besides the evaporator pressure, the thermal expansion valve reacts directly to changes in what parameter?