Question 174Refrigeration/AC - Assistant Engineer70% to pass
In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly upon what factor?
AI Explanation
The correct answer is C) temperature of the evaporator coil outlet.
In a refrigeration system, the pressure within the power element of a thermostatic expansion valve depends directly on the temperature of the refrigerant leaving the evaporator coil. This is because the power element is connected to the outlet of the evaporator, and the pressure it experiences is a function of the temperature at that point. As the evaporator coil outlet temperature changes, the pressure in the power element changes accordingly, which then adjusts the opening of the expansion valve to maintain the desired superheat.
The other answer choices are incorrect because they do not directly determine the pressure in the power element. The compressor suction pressure (A) and the temperature in the box (B) affect the system but do not directly influence the pressure in the power element. The heat transferred from the saturated liquid in the evaporator (D) is a result of the temperature at the evaporator outlet, not a direct determinant of the power element pressure.
Related Questions
#172 When a refrigeration compressor has developed a high head pressure as a result of a refrigerant overcharge, what should be done to compensate for or to correct this situation? #173 In a refrigeration system, the bulb for the thermal expansion valve is always located where? #175 What is one function of the thermal expansion valve used in a refrigeration system? #176 Which of the following illustrated thermal expansion valves would be appropriate to use on an evaporator coil with a 2 psi pressure drop, where externally adjustable superheat and a replaceable power element are both desired? Illustration GS-RA-06 #177 In a vapor compression type refrigeration cycle, the refrigerant temperature decreases the most when passing through which system component?