Cooling, heating, and power energy performance for system feasibility

Buildings with heating and cooling energy requirements are usually supplied by separated systems such as furnaces or boilers for heating, and vapour compression systems for cooling. For these types of buildings, the use of cooling, heating, and power (CHP) systems is an alternative for energy savings. Different investigations have claimed that the use of CHP systems reduces the energy consumption related to transmission and distribution of energy. However, most of these analyses are based on the reduction of operating cost without measuring the actual energy use reduction. In this study, the definition of building primary energy ratio (BPER) is introduced as a new parameter to evaluate the CHP energy performance. BPER measures the variation of the building primary energy (BPE) when the building is operated without a CHP system versus the BPE when a CHP system is used. Results show that using the thermal efficiency alone is not the best approach to describe the CHP system energy performance and that using the BPER provides a more comprehensive CHP evaluation. For this investigation, values of BPER greater than 1 indicate that primary energy is being saved for that specific time, which makes this concept a reliable tool for the CHP design and operational control.