IIR document

Coupling control of superheat and nitrogen oxides for gas engine heat pump.

Author(s) : LIU F., ZHAO N., TIAN C., MA Z., CHEN Z.

Type of article: IJR article


Gas engine heat pump (GEHP) is gradually developing due to the high energy efficiency. However, the gas engine is easily disturbed by load fluctuation, which affects the stability of GEHP operation and causes higher nitrogen oxides (NOx) emission concentrations. Therefore, an efficient control method is necessary to ensure system stability, improve energy efficiency and reduce NOx emissions. In this paper, a coupling control strategy of superheat and NOx is proposed. The results show that the superheat can maintain stability with the small overshoot and adjustment time of less than 400 s when the engine speed changes. When the superheat setting value changed continuously, the superheat overshoot and error are less than 0.5 °C and the adjustment time is about 100 s. Meanwhile, the system outlet temperature is stable, the overshoot is less than 1 °C. The amplitude variation of the refrigerating capacity is similar to the amplitude variation of the superheat. The variation range of total heat capacity is greater than that of refrigerating capacity. In addition, the performance and emission of the GEHP are respectively studied when the superheat is 4 °C and 7 °C, at the optimum excess air coefficient. The NOx emissions are always below 100 ppm, but the primary energy ratio (PER) is higher under the superheat of 4 °C. Therefore, the proposed coupling control strategy can achieve good stability, excellent performance and emission characteristics.

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Pages: 91-102


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  • Original title: Coupling control of superheat and nitrogen oxides for gas engine heat pump.
  • Record ID : 30029531
  • Languages: English
  • Source: International Journal of Refrigeration - Revue Internationale du Froid - vol. 137
  • Publication date: 2022/05
  • DOI: http://dx.doi.org/10.1016/j.ijrefrig.2022.02.011
  • Document available for consultation in the library of the IIR headquarters only.


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