[Daily Question] Registered Cost Engineer – Installation Measurement: Multiple-choice Questions with Open Options, 1.7.2022

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Units equipped with a four-way control valve, which allows for the switching between the condenser and the evaporator within the unit, thereby enabling switching between cooling and heating modes; such units that can provide cooling in summer and heating in winter are (). A. Centrifugal chiller unit B. Piston-type air-cooled chiller unit C. Absorption chiller unit D. Geothermal heat pump 【Answer】D 【Explanation】 Heat pump air-conditioning units: During cooling in summer, the indoor heat exchanger is converted into an evaporator using a four-way valve, allowing the liquid refrigerant to vaporize and thereby absorb heat from the indoor air ； And change the outdoor heat exchanger into a condenser, releasing the heat of condensation into the outdoor air. During winter heating, the four-way valve is used to convert the indoor heat exchanger into a condenser, thereby using the heat released during the condensation of the refrigerant to warm the indoor air; at the same time, the outdoor heat exchanger is converted into an evaporator, which absorbs low-grade heat from the outdoor air.