Evaluation of performance of combined heat and power systems with dual power generation units (D-CHP).

摘要

In this research, a new combined heat and power (CHP) system configuration has been proposed that uses two power generation units (PGU) operating simultaneously with different operational strategies (D-CHP). The performance of the proposed D-CHP system configuration, with one PGU operated at a constant base load and the other operated following the electric load, is quantified in terms of operational cost savings, primary energy consumption (PEC) savings, and carbon dioxide emissions (CDE) savings over a reference case employing a conventional, separate heat and power system. D-CHP system performance is also compared to standard, single PGU operational strategies. The D-CHP system configuration is first examined for four different building configurations simulated using the weather of Chicago, IL. Then, the D-CHP system feasibility study is extended to examine a full-service restaurant benchmark building in nine different U.S. climate zones. Next, the D-CHP configuration is simulated under a second operational strategy, in which one PGU operates base-loaded while the other follows the thermal load, and the two D-CHP strategies are compared. Additionally, the effect of thermal storage on D-CHP system performance is examined. Finally, the D-CHP configuration is extended to a combined cooling, heating, and power configuration (D-CCHP), and the feasibility of this configuration is examined. In addition to D-CHP and D-CCHP systems performance analyses, the parameters of power-to-heat ratio; cost, emissions and primary energy consumption spark spreads; cost and emission ratios; and thermal difference are proposed and examined as performance indicators. It was determined that D-CHP and D-CCHP system strategies can be a viable alternative to traditional CHP system or combined cooling, heating, and power (CCHP) system operational strategies, in terms of operational cost, PEC, and CDE performance. Generally, the D-CHP and D-CCHP configurations are found to perform comparably to or better than traditional CHP and CCHP configurations.