Capacity control of a vehicle air-conditioning system using pulse width modulated duty cycle compressor

Abstract

The air conditioning system is the most significant auxiliary load on a vehicle where the compressor consumed the largest from the engine, leading to high fuel consumption. Depending upon nature, the variable-capacity compressor reduces cycling on/off. It delivers cooling/heating to a cabin without adjusting the engine rpm, offering superior part-load performance to improve comfort. Consequently, power consumption is growing as an increase in inefficiency. Additionally, systems with continuous compressor modulation can automatically change their energy consumption as required. The paper aims to save energy by reducing fuel consumption in the system. It is because this technology helps us to deduct energy consumption. The test facilities were designed to determine the system capacity with refrigerant side capacity measurement with a mass flow rate of the refrigerant and enthalpy difference across the evaporator. R-134a is considered a refrigerant in this system. Pulse width modulation (PWM) with a duty cycle is used as a command controller or method of reducing power by pulsing its electrical current by effectively chopping it into discrete parts to control the capacity. The results demonstrate that a system consumed 1.2 kW power at 900 rpm, having 4 kW of the capacity. The system also utilized 2 kW power at 2500 rpm with 4.6 kW capacity, which directs the slight increase in power consumption with a significant increase in capacity. Systems with continuous compressor modulation automatically adjust their energy consumption according to the needs of the application. By using this technology of air conditioning, the owner can reduce energy consumption.

Keywords

• Air conditioner Compressor Duty cycle Energy saving Pulse width modulation