Share

IIR document

Quantification and comparison of COP improvement approaches for large-scale ammonia heat pump systems.

Author(s) : HARTMUND JORGENSEN P., OMMEN T., ELMEGAARD B.

Type of article: IJR article

Summary

The number of large-scale heat pumps (HP) implemented in Danish district heating networks has increased in recent years. The installations are often custom-made solutions designed carefully to obtain a high Coefficient of Performance (COP). This study aims at quantifying and compare five approaches for improving the COP of a heat pump, with a one-stage ammonia cycle used as the reference case with sink temperatures of 50 °C/80 °C (in/out) and source temperatures of 10 °C/3 °C. The approaches include increased complexity of cycle layout, optimization of intermediate pressure in two-stage cycles, a connection of HP cycles in series, optimization of load share between heating capacity for HPs in series, and optimal design of heat exchanger networks (HEN). The latter is based on an implementation of pinch analysis to HP HENs. The results revealed an improvement in COP by +15.8% obtained with increased complexity of cycle layout (two-stage cycle with a low-stage desuperheater) compared to a COP of 2.98 for the reference case. Connecting up to three one-stage HPs and two-stage cycles in series improved COP by 4.42% and 24.5%, respectively. The benefit of optimal load share and intermediate pressure was less than 0.5 % points for all configurations compared to reference values based on theoretical approaches. Exploiting the potential for optimal HEN increased the potential to 10.4% for one-stage cycles in series and nearly 29% for two-stage cycles increasing the COP to a maximum of 3.84.

Available documents

Format PDF

Pages: 301-316

Available

  • Public price

    20 €

  • Member price*

    Free

* Best rate depending on membership category (see the detailed benefits of individual and corporate memberships).

Details

  • Original title: Quantification and comparison of COP improvement approaches for large-scale ammonia heat pump systems.
  • Record ID : 30028720
  • Languages: English
  • Subject: Technology
  • Source: International Journal of Refrigeration - Revue Internationale du Froid - vol. 129
  • Publication date: 2021/09
  • DOI: http://dx.doi.org/10.1016/j.ijrefrig.2021.04.016
  • Document available for consultation in the library of the IIR headquarters only.

Links


See other articles in this issue (32)
See the source

Indexing