Numerical simulation of unsteady airflow organization and cold island effect in air source heat pump unit
During winter heating operations, the cold air discharged by air source heat pump (ASHP) units accumulates around them, resulting in a cold island effect that decreases the system's heating capacity. This paper presents an unsteady computational fluid dynamics (CFD) simulation model to investig...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-10-01
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| Series: | Case Studies in Thermal Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X25010172 |
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| Summary: | During winter heating operations, the cold air discharged by air source heat pump (ASHP) units accumulates around them, resulting in a cold island effect that decreases the system's heating capacity. This paper presents an unsteady computational fluid dynamics (CFD) simulation model to investigate the airflow organization of a single ASHP unit. It examines how environmental temperature, wind speed, and air volume influence airflow patterns and analyzes the effects on the coefficient of performance (COP). The findings reveal a maximum relative error of 14.5 % between the simulated and experimental COP results. The airflow organization progresses through three stages: viscosity-dominated, accelerated suction, and periodic ejection. The cold island effect can lead to a 3.28 % drop in baseline COP compared to the theoretical COP, with decreases reaching 4.17 % at an ambient temperature of 15 °C and 6.54 % at an air volume of 13527 m3/h. The research findings of this study provide a basis for the quantitative engineering analysis of performance degradation in single-unit air-source heat pump systems caused by the cold island effect. Additionally, the introduction of a non-steady-state model offers new insights into the precise characterization of the cold island effect in air-source heat pump units. |
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| ISSN: | 2214-157X |