In heat pump systems, two ______ devices are used.

In heat pump systems, two ______ devices are used.

• A. Compressor
• B. Expansion
• C. Condenser
• D. Evaporator

Answer: (B)

The main idea is metering refrigerant flow through expansion devices. In heat pump systems, the liquid refrigerant must be slowed down and reduced in pressure before it enters the evaporator so it can absorb heat effectively. When a system uses two evaporator circuits or two stages, each circuit needs its own metering point to control how much refrigerant enters it. That’s why two expansion devices are used — they precisely throttle the high‑pressure liquid to the low‑pressure side for each evaporator path, helping the system regulate capacity and maintain efficiency in both heating and cooling. The other components (compressor, condenser, evaporator) are essential, but they don’t describe having two separate metering points.

The main idea is metering refrigerant flow through expansion devices. In heat pump systems, the liquid refrigerant must be slowed down and reduced in pressure before it enters the evaporator so it can absorb heat effectively. When a system uses two evaporator circuits or two stages, each circuit needs its own metering point to control how much refrigerant enters it. That’s why two expansion devices are used — they precisely throttle the high‑pressure liquid to the low‑pressure side for each evaporator path, helping the system regulate capacity and maintain efficiency in both heating and cooling. The other components (compressor, condenser, evaporator) are essential, but they don’t describe having two separate metering points.