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Experimental investigation of steady and transient heating performance of a variable-speed air-source heat pump.

Author(s) : YOUSAF S., TANVEER M. M., BRADSHAW C. R.

Type of article: IJR article

Summary

High-fidelity experimental investigation of split heat pump systems in steady and transient behaviour remains limited, particularly with variable speed and cycling operation relevant to the real world use. This work investi gates steady-state and dynamic performance for a 14kW variable-speed R-410A split heat pump tested in heating mode in a twin psychrometric chamber. Steady-state tests (𝑛=33) spanning outdoor temperatures from -8.3◦C to 15.6◦C yielded heating capacities of 3.6-16 kW and COP values of 3.2–5.5, with part-load operation (40-100%) maintaining high efficiency (COP= 4.8-5.1). Dynamic tests (𝑛=10) include cold- and warm-start operation at AHRI H1 (outdoor dry bulb = 8.3◦C) and H3 (outdoor dry bulb = −8.3◦C) conditions, with cold-start time con stants exceeding warm-start by 10–20%, indicating slower system response due to thermal soak and refrigerant redistribution from extended off-periods. Circuit-level temperature measurements revealed non-uniform temper ature distributions among parallel circuits (up to 10 °C spread) during startup and shutdown, suggesting poten tial refrigerant maldistribution. Measurements include refrigerant pressures and temperatures at component in lets/exits, air-side conditions, compressor shell temperatures, circuit by circuit temperatures along with ancillary component thermal response. This study enhances understanding of heat pump operation through steady-state characterization across broad operating conditions and transient startup/shutdown sequences including com pressor and fan speed cycling. These data enable calibration and validation of empirical maps, gray-box models, and high-fidelity steady-state and dynamic models, complete with heat exchanger circuit layouts, compressor specifications, refrigerant charge data, and system architecture. This dataset enables examination of how startup and cycling behavior drives deviations between steady state laboratory ratings and transient operation, providing experimental grounding for models that capture transient operation. All experimental data is publicly available, providing a validation benchmark for future empirical, physics-based, and reduced-order models.
 

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Details

  • Original title: Experimental investigation of steady and transient heating performance of a variable-speed air-source heat pump.
  • Record ID : 30034984
  • Languages: English
  • Subject: Technology
  • Source: International Journal of Refrigeration - Revue Internationale du Froid - vol. 188
  • Publication date: 2026/08
  • DOI: http://dx.doi.org/ 10.1016/j.ijrefrig.2026.106988

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