IIR document

Transient simulation of R744 hybrid ground coupled heat pump with Modelica.

Number: pap. ID40

Author(s) : JIN Z., EIKEVIK T. M., NEKSÅ P., et al.


This article attempts to investigate the Air-conditioning application of R744(CO2) as a working fluid for a ground coupled heat pump (GCHP) .The system utilises a combination of ambient air and ground as a heat sink in AC mode. According to the characteristic of reverse transcritical CO2 cycle and ground heat exchanger, CO2 GCHP dynamic models are developed and the transient performance is simulated in the Modelica/ Dymola environment. During the simulation, the short term response borehole model is utilized to analyse the transient thermal response of borehole to the CO2 GCHP system. Simulation result shows the outlet fluid temperature from the borehole has a significant effect on the CO2 heat pump system, while the introduced air-cooled gas cooler well improves the concerned performance, meanwhile the optimal capacity of air-cooled gas cooler and its optimal operating pressure is also provided. The developed hybrid CO2 GCHP system shows good competitiveness in the air conditioning application and the optimal averaged system COP is obtained with 3.45.

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Pages: 7 p.


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  • Original title: Transient simulation of R744 hybrid ground coupled heat pump with Modelica.
  • Record ID : 30013147
  • Languages: English
  • Source: 11th IIR Gustav Lorentzen Conference on Natural Refrigerants (GL2014). Proceedings. Hangzhou, China, August 31-September 2, 2014.
  • Publication date: 2014/08/02


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