Screening Tool for the Evaluation of Combined Cooling, Heating, and Power Systems in Existing Office Buildings

Abstract

Combined Cooling, Heating, and Power (CCHP) systems have been widely recognized as a key alternative for heat and electricity generation because of their ability to consume fuel more efficiently, which translates into a reduction in carbon dioxide emission, considered the main factor contributing to global warming. However, economic analyses do not always favor the implementation of this technology. Even though CCHP systems offer other benefits such as power reliability, power quality, and fuel source flexibility, they are often negated as a feasible alternative because of these poor economic indicators. Therefore, a more comprehensive evaluation of the system should be considered. This is particularly true in an environment where economic, environmental, political, and logistical problems associated with increasing centralized electrical power production are becoming more difficult to overcome. In addition, as consumers continue to be more involved and to develop a better understanding of energy choices, the demand for technology that better meets their energy needs is increasing. To promote the development of CCHP projects, it is important to facilitate, without any cost, a first order analysis of this technology to determine if a more cost intensive, in-depth analysis should be performed. This analysis can be done by using screening tools such as the CCHP Screening Tool for Existing Office Buildings (CCHP-ST-EOB) proposed in this study. Screening tools should be as accurate as possible while maintaining the simplicity of their data input in order to make it easy to use by a broad audience that may include building owners and managers without engineering background. In this sense, the CCHP-ST-EOB uses a methodology that translates energy consumption from utility bills as input into hourly energy consumption for a more accurate analysis of the matching between the demand and supply sides. This tool takes into consideration partial load efficiencies for the power generation unit and absorption chiller for a more realistic simulation of the system performance. Results are presented in terms of cost, primary energy consumption, and CO2 emission. The tool is available to be downloaded free of charge at http://microchp.msstate.edu/thankyou.html.