Complex sentence: In comparison, a compressor refrigerator uses an electrically powered compressor to increase the pressure on the gaseous refrigerant, the resulting hot high pressure gas is condensed to a liquid form by cooling in a heat exchanger with the external environment (usually air in the room).
Split into simpler sentences: In comparison, a compressor refrigerator uses an electrically powered compressor to increase the pressure on the gaseous refrigerant. The resulting hot, high-pressure gas is condensed to a liquid form by cooling in a heat exchanger ("condenser") that is exposed to the external environment (usually air in the room).