تجزیه و تحلیل و بهینه سازی سیستم CCHP بر اساس انرژی، اقتصادی، و ملاحظات زیست محیطی

Analysis of combined cooling, heating, and power (CCHP) systems is frequently based on reduction of operating cost without measuring the actual energy use and emissions reduction. CCHP systems can be optimized based on different optimization criterion such as: energy savings, operation cost reduction or minimum environmental impact. In this study, CCHP systems operated following the electric load (FEL) and the thermal load (FTL) strategies are evaluated and optimized based on: primary energy consumption (PEC), operation cost, and carbon dioxide emissions (CDE). This study also includes the analysis and evaluation of an optimized operational strategy in which a CCHP system follows a hybrid electric–thermal load (HETS) during its operation. Results show that CCHP systems operating using any of the optimization criteria have better performance than CCHP systems operating without any optimization criteria. For the evaluated city, the optimum PEC and cost reduction are 7.5% and 4.4%, respectively, for CCHP-FTL, while the optimum CDE reduction is 14.8% for CCHP-FEL. Results also show that the HETS is a good alternative for CCHP systems operation since it gives good reduction of PEC, cost, and CDE. This optimized operation strategy provides a good balance among all the variables considered in this paper.

The term CCHP (combined cooling, heating, and power) describes all electrical power generation systems that utilize recoverable waste heat for space heating, cooling, and domestic hot water purposes. The main difference between CCHP systems and the typical methods of electric generation is the utilization of the waste heat rejected from the prime mover in order to satisfy the thermal demand of a facility (cooling, heating, or hot water needs). One of the most basic goals of CCHP systems is to ensure that it is a more attractive option than traditional power supply. The end goals of CCHP systems are to ensure reduction of primary energy, cost, emissions, or a combination of all of them. To achieve these goals, CCHP are usually operated using two basic strategies: following the electric load (FEL) and following the thermal load (FTL). However, in addition to the operation strategies it is necessary to apply optimization criteria to guarantee the benefits of CCHP systems over conventional technologies. The CCHP operation strategy will dictate the loading and fuel consumption of the prime mover and thus the energy consumption profile of the CCHP system.

This paper presented an analysis and optimization of CCHP systems operated FEL and FTL. The system was optimized based on different optimization criterion: energy savings, operation cost reduction or minimum environmental impact. An operational strategy in which a CCHP system follows a hybrid electric–thermal load (HETS) during its operation was also analyzed and evaluated. All the strategies were compared based on: PEC, operation cost, and CDE. From the results, for the evaluated city, it can be concluded that all the optimization criteria yield better results than CCHP operating FEL or FTL without any optimization. Also, that the best optimization criterion is the PE-O since it minimizes the PEC, while reducing cost and CDE. For CCHP-FTL, the results obtained for the operation cost and the CDE using the PE-O are similar to the optimized cost and CDE obtained for CCHP systems operating under the OC-O and ER-O. For CCHP-FTL the cost is 15% higher than the optimal cost obtained using the OC-O; while the CDE is 7.7% higher than the optimal value obtained using the ER-O