Question 180Refrigeration & AC - Assistant Engineer
70% to passThe 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?
Aan increase in the evaporator pressure
Ba decrease in sensing bulb temperature
Can increase in sensing bulb temperature
Dincreasing the superheat setting of the valve
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.
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