سیستم های نیروی خنک کننده و حرارت ی ترکیب شده عملیات هیبرید الکتریکی حرارتی

Micro-combined cooling, heating and power (mCCHP), typically designated as less than 30 kW electric, is a technology that generates electricity at or near the place where it is used. The waste heat from the electricity generation can be used for space cooling, space heating, or water heating. The operation of mCCHP systems, while obviously dependent upon the seasonal atmospheric conditions, which determine the building thermal and power demand, is ultimately controlled by the operation strategy. Two of the most common operation strategies are to run the prime mover in accordance to either electrical or thermal demand. In this study, a mCCHP system operating following a hybrid electric-thermal load (FHL) is proposed and investigated. This operation strategy is evaluated and compared with mCCHP systems operating following the electric load (FEL) and operating following the thermal load (FTL). This evaluation and comparison is based on site energy consumption (SEC), primary energy consumption (PEC), operational cost, and carbon dioxide emission reduction (CDE). Results show that mCCHP systems operated following the hybrid electric-thermal load have better performance than mCCHP-FEL and mCCHP-FTL. mCCHP-FHL showed higher reductions of PEC, operational cost, and carbon dioxide emissions than the ones obtained for the other two operation strategies for the evaluated case.

A typical mCCHP system consists of a power generation unit (PGU), a heat exchanger to recover heat from the PGU exhaust, an absorption chiller system to generate chilled water, a heating coil, and an auxiliary boiler (see Fig. 1). The difference between mCCHP systems and the typical methods of power plant electric generation is the use of the waste heat rejected from the PGU in order to satisfy the thermal demand of a facility. Traditional power plants convert about 30% of the fuel’s available energy into electric power since most of the energy content of the fuel is lost at the power plant through the discharge of waste heat. In addition, energy losses occur in the transmission and distribution of electric power to individual users. However, mCCHP systems produce both electric and useable thermal energy onsite or near site, reducing the energy losses that occur in the transmission and distribution, converting as much as 80% of the fuel into useable energy.

This study proposed and investigated a mCCHP system operating following a hybrid electric-thermal load strategy. The proposed operation strategy is evaluated and compared with mCCHP systems operating following the electric load and mCCHP systems operating following the thermal load. The evaluation and comparison was based on SEC, PEC, operational cost, and CDE. Results show that mCCHP-FHL has better performance than mCCHP-FEL and mCCHP-FTL. mCCHP-FHL showed higher reductions of PEC, operational cost, and carbon dioxide emissions than the ones obtained for the other two operation strategies for the evaluated case. This is mainly due to the fact the mCCHP-FHL follows the operation strategy, either electric load or the thermal load that consumes less primary energy through the year