Investigation of energy-efficient strategy for direct expansion air-cooled air conditioning systems

• Combined theoretical–empirical models for performance prediction of the DX air conditioning system.
• Field tests conducted for a real building's air-cooled DX rooftop package.
• Numerical algorithm developed and implemented in transient simulation software.
• Liquid pressure amplification method appears to be effective for the study.
• About 25.3% in average and up to 42% drop in energy consumption.

This paper addresses the energy saving significance of air-cooled direct expansion (DX) air conditioning systems using liquid pressure amplification (LPA) technology along with proposed theoretical–empirical models for the system components. This method utilizes a refrigerant pump in the liquid line to allow the system operation at lower condensing pressure. An actual DX rooftop package is used for data collection. The performance of the proposed method is simulated using transient simulation software. Simulation tool was validated by comparing predicted and measured power consumption of the rooftop package. Results show that up to 42% power savings can be obtained using this approach.