Energy and Power Engineering, 2014, 6, 69-81 Published Online May 2014 in SciRes. http://www.scirp.org/journal/epe http://dx.doi.org/10.4236/epe.2014.65008 How to cite this paper: Kritsanawonghong, S., et al. (2014) Feasibility Study of Optimal Sizing of Micro-Cogeneration Sys- tem for Convenience Stores in Bangkok. Energy and Power Engineering, 6, 69-81. http://dx.doi.org/10.4236/epe.2014.65008 Feasibility Study of Optimal Sizing of Micro-Cogeneration System for Convenience Stores in Bangkok Suapphong Kritsanawonghong 1 , Weijun Gao 1 , Pawinee Iamtrakul 2 1 Department of Architecture, Faculty of Environmental Engineering, The University of Kitakyushu, Kitakyushu, Japan 2 Department of Urban Environmental Planning and Development, Faculty of Architecture and Planning, Thammasat University, Pathum Thani, Thailand Email: suapphong@yahoo.com Received 22 March 2014; revised 22 April 2014; accepted 29 April 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract In this paper, the optimization of micro-cogeneration (µ-CHP) system sizing for convenience stores in Thailand is conducted under the present condition of fuel prices and tariff rates. The as- sessment of (µ-CHP) system performance is analyzed by using Primary Energy Saving (PES) Ratio for evaluating the energy performance. Also, the Annual Cost Saving Ratio (CSR) and Payback Pe- riod (PBP) are used for evaluating the economic performance of µ-CHP system. The analysis re- sults show the optimal size of µ-CHP system under possible conditions including the operating schedule and system’s efficiency were conducted. Keywords Convenience Stores, Micro-Cogeneration System, Energy Efficiency, Economic Assessment, Thailand 1. Introduction The utilization of alternative energy is one of the effective methods to improve the energy efficiency and reduc- tion of primary energy demand, i.e. the implementation of PV system or other available energy sources in each area. Cogeneration, which was also called Combined Heat and Power or CHP, is the high efficient system to generate power (electricity) and thermal energy from a single fuel source. The CHP system has been widely used as the effective technology for power generation with lower cost and also reduced environmental emissions