1. Department of Energy Technology, School of Energy, Environment and Materials, King Mongkut's University of Technology, Thonburi, Bangkok 10140, Thailand e-mail:
2. Department of Energy Technology, Faculty of Industrial Education and Technology, King Mongkut's University of Technology, Thonburi, Bangkok 10140, Thailand e-mail:
3. Department of Alternative Energy Development and Efficiency, Ministry of Energy, 17 Rama I Road, Kasatsuk Bridge, Pathumwan, Bangkok 10330, Thailand e-mail: