Potential Energy Saving by Variable Speed Control of Compressor for Roof-Top Bus Air Conditioning System
[html] Henry Nasution [a, b], Md Nor Musa , Hayati Abdullah , Mat Nawi Wan Hassan , Mohammad Akmal Baharain , Sapiah Sulaiman , and Mohamed Khamis Mansour [c]
a Department of Mechanical Engineering, Faculty of Industrial Technology
Universitas Bung Hatta, Indonesia
b Department of Thermo-Fluids, Faculty of Mechanical Engineering
Universiti Teknologi Malaysia
Tel: +607 5534878, +607 5533333 Fax: +607 5566159
c Department of Mechanical Engineering, Faculty of Engineering
Alexandria University, Egypt
Email: henrynasution@yahoo.com
Email: mdnor@fkm.utm.my
Email: hayati@fkm.utm.my
Email: matnawi@fkm.utm.my
Email: akmal@utm.my
Email: sapiah@utm.my
Email: mdkhamis@gmail.com
Abstract - The potential of a variable speed compressor running with a controller to provide enhanced load-matching capability, energy saving and thermal comfort for application in roof-top bus air conditioning system is demonstrated. This paper presents an algorithm developed based on fuzzy logic control (FLC) and programmable logic control (PLC), which allows selected compressors to run at the appropriate operating speed. The main objective of the experimental work is to evaluate the energy saving obtained when the FLC and PLC algorithm, through an inverter, continuously regulates the compressor speed. It demonstrates better control of the compressor operation in terms of energy consumption as compared to the control by using a thermostat imposing on/off cycles on the compressor at the nominal frequency of 50 Hz. The experimental set-up consists of original components from the air conditioning system of a compact passenger vehicle. The experiments were conducted with temperature set-points for the conditioned space of 22 C. Measurements were taken at a time interval of one minute. The experimental results indicate that the proposed technique can save energy and improve indoor comfort significantly for roof-top bus air conditioning systems compared to the conventional (on/off) control technique. The experimental results also showed that more energy saving can be obtained through the use of FLC when compared to the PLC and on/off control.
Conclusion - A series of experiments for a variable speed automotive air conditioning system has been conducted at various frequencies from 5 to 50 Hz. The impact of variable speed of the cabin temperature and energy consumption has been analyzed experimentally. The results indicate that the cabin temperature and energy consumption is dependent on the frequency of the motor. The temperature of the cabin decreases as the frequency of the motor increases, and vice versa. The inverter allows for more than one temperature setting. When the frequency increases, the cabin temperature decreases while the energy consumption increases. A higher energy saving is achieved when the motor runs at a lower frequency. The high energy saving at a lower frequency is mostly due to the lesser compressor energy consumption. The application of variable speed controls to air conditioning offers the potential for substantial energy savings for energy efficient application. The study indicates that the cabin temperature may be controlled by an inverter driven motor to achieve energy savings. The study has shown that FLC gives a higher saving and provides a better control when compared to the PLC and on/off controller. [/html]