Thermodynamic analysis of a novel combined heat and power system incorporating a CO2 heat pump cycle for enhancing flexibility

Chen, Heng; Yao, Xianhuai; Li, Juan; Xu, Gang; Yang, Yongping; Liu, Wenyi; Chen, Honggang

doi:10.1016/j.applthermaleng.2019.114160

Cited by 11 publications

(2 citation statements)

References 51 publications

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“…Excavating the peak shaving capacity of CHP units is a crucial measure to promote the consumption of renewable power generation [1]. To solve the above problems, a large number of scholars have carried out heat-power decoupling technology research, Energies 2022, 15, 9337 2 of 21 such as coupling electric boiler heating [2][3][4], coupled heat pump heating [5][6][7], additional heat storage equipment [8,9], high back-pressure heat supply transformation [10,11], lowpressure cylinder cut-out heating transformation [12] and bypass heating [13] technologies, the peak shaving ability of CHP units has been improved.…”

Section: Introductionmentioning

confidence: 99%

Optimal Multi-Mode Flexibility Operation of CHP Units with Electrode Type Electric Boilers: A Case Study

Dong

et al. 2022

Energies

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With the in-depth development of flexibility retrofit in combined heat and power (CHP) units, the unit commitment mode of energy supply equipment in CHP plants is more flexible. This paper presents a multi-mode flexible operation method for CHP plants with electrode electric boilers. Firstly, a simulation model of the operation characteristics of each unit in different operation modes is established, and the corresponding features of electrical and thermal outputs are obtained. Subsequently, a decision-making model of the unit commitment mode of energy supply equipment is set up, and the selection rules of the unit commitment mode of the unit under low heat load, medium heat load, and high heat load are achieved. Finally, under different unit operation combinations, a plant-level optimum load dispatch model is obtained, and the actual operating data of the CHP plant is used for optimization and comparison analysis. The results show that compared to the unit commitment mode of high back pressure and low-pressure cylinder cutting-off (HBP + LPCC), the unit commitment mode of high back pressure and extraction heating (HBP + EH) has more room for energy-saving optimization. Under the premise of safe and reliable operation, the high back pressure (HBP) unit can be loaded as much as possible. While in the combined operating of HBP + EH, the energy-saving space for optimized load dispatching is not large, so a fixed proportion of the electrical load may be considered; under the auxiliary service subsidy policy, the input power of the electric boiler can be appropriately increased; the greater the heat load of the whole plant, the more pronounced the energy-saving effect of optimum load dispatch.

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Section: Introductionmentioning

confidence: 99%

Optimal Multi-Mode Flexibility Operation of CHP Units with Electrode Type Electric Boilers: A Case Study

Dong

et al. 2022

Energies

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“…The results revealed that the COP and other performance indicators of the system improved by utilizing zeotropic mixture, and the introduced system was technically reliable and economically appealing. A similar concept with a CO 2 ‐based heat pump was assessed, and the productivity of the proposed plant was analyzed thermodynamically by Chen et al 36 The heat pump was employed in such a way to utilize the excess generated power of the CCHP plant to produce district heating load. The model's findings demonstrated that employing the heat pump within the system could boost the electric efficiency of the system up to 7.7%.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic and thermoeconomic analyses of an ejector/booster enhanced heat pump system with zeotropic mixture

2020

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Summary In the current investigation, a novel ejector‐enhanced heat pump system was presented and comprehensively evaluated using zeotropic mixtures. In the suggested plant, a booster was added to the conventional ejector‐enhanced system to expand its performance. Moreover, the suggested plant was modeled in a way to operate zeotropic mixtures, in order to maximize the productivity of the system. The plant was investigated with regard to energy, exergy, and thermoeconomic analyses to have a deep insight of the performance characteristics, that is, exergy efficiency, COP, and unit price of the product. To this end, a parametric evaluation was conducted to predict the performance characteristics of the plant by changing the value of different input variables. The results of exergy analysis indicated that the maximum exergy annihilation (7.784 kW) was associated with the ejector. The proposed system was also compared with a conventional system, and the findings unfolded that the COP of the proposed system surpassed the conventional system by up to 25%. Moreover, the outcomes of thermoeconomic analysis showed that the unit product cost of the proposed system is 133.596 $/GJ. The outcomes further demonstrated that the highest performance of the plant was concluded using R‐600/R‐143a mixture fluid with R‐600 mass fraction of 0.45. The sensitivity evaluation further indicated that, by enhancing the condenser temperature, exergetic efficiency and heating load increased while COP and unit cost of product decreased. Moreover, there was an optimum local point, in terms of exergetic efficiency (29.5%), when the booster pressure ratio is about 1.4. In addition, at the ejector pressure lift of 1.15, the exergetic efficiency was maximized locally. The heating load of the system, however, increased continually with increasing pressure lift. The proposed system showed a decent functionality with respect to thermodynamic and thermoeconomic criteria.

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Thermodynamic analysis of a parallel type organic Rankine cycle and ejector heat pump combined cycle

Zhang

Lin

Tan

2021

Applied Thermal Engineering

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Thermodynamic analysis of a novel combined heat and power system incorporating a CO2 heat pump cycle for enhancing flexibility

Cited by 11 publications

References 51 publications

Optimal Multi-Mode Flexibility Operation of CHP Units with Electrode Type Electric Boilers: A Case Study

Optimal Multi-Mode Flexibility Operation of CHP Units with Electrode Type Electric Boilers: A Case Study

Thermodynamic and thermoeconomic analyses of an ejector/booster enhanced heat pump system with zeotropic mixture

Thermodynamic analysis of a parallel type organic Rankine cycle and ejector heat pump combined cycle

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