Design considerations for combined cooling, heating, and power systems at altitude

Combined cooling, heating, and power (CCHP) is a technology that makes better use of fuels as consequence of its high overall efficiency, which can be as high as 80%. CCHP systems aid in the reduction of energy consumption by recovering otherwise wasted heat and using it to provide heating and cooling. As a result, they also have the potential to reduce carbon and other pollutant emissions. Generally, for CCHP systems’ components, manufacturers include specifications on the performance of the equipment. However, these specifications are normally given for sea level operation. Changes in altitude affect the performance of any of the CCHP systems’ components that are open to the atmosphere due to changes in the properties of the air, such as atmospheric pressure and humidity. This study focuses on considerations for CCHP systems design at altitude. The analysis covers the processes affected by altitude and their specific application on how to assess the performance of the individual components of CCHP systems when operating at altitude. This paper also summarizes the analysis by presenting equations that can be used in the design stage of CCHP systems in order to account for equipment capacity variation, or in simplified simulations such as those for screening tools, without having a detailed simulation that some times are not cost-effective due to the time and human effort to accomplish it.