What is a typical purpose of a liquid-to-suction heat exchanger in refrigeration systems?

What is a typical purpose of a liquid-to-suction heat exchanger in refrigeration systems?

• A. Increase suction pressure
• B. Increase liquid sub-cooling
• C. Increase discharge pressure
• D. Reduce refrigerant charge

Answer: (B)

The main idea is to subcool the liquid refrigerant after it leaves the condenser. A liquid-to-suction heat exchanger uses heat transfer from the hot liquid to the colder suction gas returning to the compressor, cooling the liquid below its condensation temperature. This subcooling means that when the liquid expands, more of it stays liquid in the evaporator, reducing flash gas and allowing more of the refrigerant to absorb heat in the evaporator—improving refrigeration effect and overall efficiency. At the same time, the suction gas is warmed slightly, increasing the compressor’s suction superheat, which helps prevent liquid from entering the compressor. This device does not purposefully raise suction pressure, raise discharge pressure, or reduce the refrigerant charge.

The main idea is to subcool the liquid refrigerant after it leaves the condenser. A liquid-to-suction heat exchanger uses heat transfer from the hot liquid to the colder suction gas returning to the compressor, cooling the liquid below its condensation temperature. This subcooling means that when the liquid expands, more of it stays liquid in the evaporator, reducing flash gas and allowing more of the refrigerant to absorb heat in the evaporator—improving refrigeration effect and overall efficiency. At the same time, the suction gas is warmed slightly, increasing the compressor’s suction superheat, which helps prevent liquid from entering the compressor. This device does not purposefully raise suction pressure, raise discharge pressure, or reduce the refrigerant charge.