Free sample · interactive 3D training
How a heat pump works
Follow the refrigerant around a split heat pump in cooling and heating mode: compressor, reversing valve, metering device and both coils.
Read the whole walkthrough
1. A heat pump moves heat
It does not make heat, it moves it. A sealed loop of refrigerant picks heat up in one coil and drops it off in the other. In cooling mode the indoor coil collects heat from your home and the outdoor coil rejects it outside.
2. Compressor · the heart
The compressor squeezes low-pressure refrigerant vapor into hot, high-pressure gas. That pressure is what drives the refrigerant around the loop. Cool vapor comes in on the suction side, and hot gas leaves on the discharge side.
3. Scroll compressor
Inside, two interleaved spirals: one fixed, one orbiting. Gas is trapped at the rim in crescent-shaped pockets, swept inward as the pockets shrink, and leaves at the center at high pressure and temperature.
4. Reversing valve · cooling mode
The reversing valve is a four-way switch. In cooling mode, hot gas from the compressor is steered to the outdoor coil, and the cool vapor returning from the indoor coil is steered back to the compressor.
5. Reversing valve · heating mode
A small pilot solenoid shifts a slide inside the valve. The same hot gas now feeds the indoor coil, and the outdoor coil becomes the suction side. The loop runs backwards, so the coils swap jobs.
6. Metering device · the pressure drop
Warm liquid refrigerant squeezes through a tiny opening in the metering device. Pressure and temperature fall sharply, so what leaves is a very cold liquid and vapor mix, ready to absorb heat in the coil that follows.
7. Coils and fans · heat in, heat out
Air moves across each coil. In cooling mode the indoor coil is the evaporator: cold refrigerant absorbs heat from the air and boils to vapor. The outdoor coil is the condenser: it dumps that heat outside as the vapor turns back to liquid.
8. Checks a technician makes
Gauges and clamp thermometers on these lines give superheat and subcooling, which show whether the charge and airflow are right. Always confirm airflow first, and only certified technicians may open the refrigerant circuit.
Hands-on practice
Heating call: follow the refrigerant
It is a cold morning and the thermostat is calling for heat. Show that you can find the parts that make a heat pump move heat inside.
Click the Practice button in the player. You click parts in the 3D model and make the calls a technician would, with hints, feedback and a star score. Inside SOPpal, finishing a task earns XP.
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