To improve the overall thermal efficiency of the organic Rankine cycle（ ORC）, a simulation study was carried out for a combined heat and power（ CHP） system, using the Redlich-Kuang-Soave（ RKS） equation of state....To improve the overall thermal efficiency of the organic Rankine cycle（ ORC）, a simulation study was carried out for a combined heat and power（ CHP） system, using the Redlich-Kuang-Soave（ RKS） equation of state. In the system,R245 fa was selected as the working fluid. A scroll expander was modeled with empirical isentropic expansion efficiency.Plate heat exchangers were selected as the evaporator and the condenser, and detailed heat transfer models were programmed for both one-phase and two-phase regions. Simulations were carried out at seven different heat source temperatures（ 80,90, 100, 110, 120, 130, 140 ℃） in combination with eight different heat sink temperatures（ 20, 25, 30, 35, 40, 45, 50,55 ℃）. Results showthat in the ORC without an internal heat exchanger（ IHE）, the optimum cycle efficiencies are in the range of 7. 0% to 7. 3% when the temperature differences between the heat source and heat sink are in the range of 70 to90 ℃. Simulations on CHP reveal that domestic hot water can be produced when the heat sink inlet temperature is higher than40 ℃, and the corresponding exergy efficiency and overall thermal efficiency are 29% to 56% and 87% to 90% higher than those in the non-CHP ORC, respectively. It is found that the IHE has little effect on the improvement of work output and efficiencies for the CHP ORC.展开更多
A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump(AHP) in a gas-steam combined cycle(GSCC) power plant. The system can decrease energy c...A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump(AHP) in a gas-steam combined cycle(GSCC) power plant. The system can decrease energy consumption and further improve the energy utilization. The performance evaluation criteria are calculated, and exergy analysis for key components are implemented in terms of the energy and exergy analysis theory. Besides, the change of these criteria is also revealed before and after modification. The net power output approximately increases by 21738 kW, and equivalent coal consumption decreases by 5.58 g/kWh. A 1.81% and 1.92% increase in the thermal and exergy efficiency is respectively obtained in the new integrated system as the heating load is 401095 kJ at 100% condition. Meanwhile, the appropriate extraction parameters for heating have been also analyzed in the two systems. The proposed scheme can not only save energy consumption but also reduce emission and gain great economic benefit, which is proven to be a huge potential for practical application.展开更多
This study presents an ORC-HP combined system driven by diesel engine exhaust. This paper focuses on the feasibility and performance of the combined system under heating mode to heat a coach. The performances of the c...This study presents an ORC-HP combined system driven by diesel engine exhaust. This paper focuses on the feasibility and performance of the combined system under heating mode to heat a coach. The performances of the combined system with different parameters, including condensation temperature and evaporation pressure in ORC system, gas cooler outlet pressure, gas cooler outlet temperature and evaporation temperature in HP system, have been analyzed. The results show that the combined system can fully meet the demand of heat production. The optimal flow division ratio(rp) of 0.32 is selected by analyzing the system performance. Low condensation temperature is beneficial to the combined system performance. There exists a suitable range of evaporation temperature, gas cooler outlet pressure and gas cooler outlet temperature to achieve excellent performance. The heating coefficient of performance(COP_h) shows a first increasing and then decreasing trend with gas cooler outlet pressure, namely there exists an optimal gas cooler outlet pressure that achieves the maximum COP_h. The maximum total efficiency, COP_h and heating capacity can reach up to 48.44%, 4.78 and 176.56 kW, respectively. These results show significant energy savings by applying the ORC-HP combined system.展开更多
基金Special Fund for IndustryUniversity and Research Cooperation(No.2011DFR61130)
文摘To improve the overall thermal efficiency of the organic Rankine cycle（ ORC）, a simulation study was carried out for a combined heat and power（ CHP） system, using the Redlich-Kuang-Soave（ RKS） equation of state. In the system,R245 fa was selected as the working fluid. A scroll expander was modeled with empirical isentropic expansion efficiency.Plate heat exchangers were selected as the evaporator and the condenser, and detailed heat transfer models were programmed for both one-phase and two-phase regions. Simulations were carried out at seven different heat source temperatures（ 80,90, 100, 110, 120, 130, 140 ℃） in combination with eight different heat sink temperatures（ 20, 25, 30, 35, 40, 45, 50,55 ℃）. Results showthat in the ORC without an internal heat exchanger（ IHE）, the optimum cycle efficiencies are in the range of 7. 0% to 7. 3% when the temperature differences between the heat source and heat sink are in the range of 70 to90 ℃. Simulations on CHP reveal that domestic hot water can be produced when the heat sink inlet temperature is higher than40 ℃, and the corresponding exergy efficiency and overall thermal efficiency are 29% to 56% and 87% to 90% higher than those in the non-CHP ORC, respectively. It is found that the IHE has little effect on the improvement of work output and efficiencies for the CHP ORC.
基金supported by National Natural Science Foundation of China No. 51274224the China Scholarship Council (CSC) (No. 201706440092)
文摘A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump(AHP) in a gas-steam combined cycle(GSCC) power plant. The system can decrease energy consumption and further improve the energy utilization. The performance evaluation criteria are calculated, and exergy analysis for key components are implemented in terms of the energy and exergy analysis theory. Besides, the change of these criteria is also revealed before and after modification. The net power output approximately increases by 21738 kW, and equivalent coal consumption decreases by 5.58 g/kWh. A 1.81% and 1.92% increase in the thermal and exergy efficiency is respectively obtained in the new integrated system as the heating load is 401095 kJ at 100% condition. Meanwhile, the appropriate extraction parameters for heating have been also analyzed in the two systems. The proposed scheme can not only save energy consumption but also reduce emission and gain great economic benefit, which is proven to be a huge potential for practical application.
基金financially supported by National Natural Science Foundation of China (Grant No. 51776005, Grant No. 51376011)National Key R&D Program of China (Grant No. 2016YFE0124900)
文摘This study presents an ORC-HP combined system driven by diesel engine exhaust. This paper focuses on the feasibility and performance of the combined system under heating mode to heat a coach. The performances of the combined system with different parameters, including condensation temperature and evaporation pressure in ORC system, gas cooler outlet pressure, gas cooler outlet temperature and evaporation temperature in HP system, have been analyzed. The results show that the combined system can fully meet the demand of heat production. The optimal flow division ratio(rp) of 0.32 is selected by analyzing the system performance. Low condensation temperature is beneficial to the combined system performance. There exists a suitable range of evaporation temperature, gas cooler outlet pressure and gas cooler outlet temperature to achieve excellent performance. The heating coefficient of performance(COP_h) shows a first increasing and then decreasing trend with gas cooler outlet pressure, namely there exists an optimal gas cooler outlet pressure that achieves the maximum COP_h. The maximum total efficiency, COP_h and heating capacity can reach up to 48.44%, 4.78 and 176.56 kW, respectively. These results show significant energy savings by applying the ORC-HP combined system.
