Effects of reversing valves on heat pump performance

Damasceno, G.; Rooke, S. P.; Goldschmidt, Victor

doi:10.1016/0140-7007(91)90081-q

Cited by 8 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where φ SP is the opening setpoint, which is either 1 or 0 depending on the on/off status of each check valve. The heat loss from the high pressure side is primarily driven by the temperature difference between the discharge gas and the suction gas, and can be characterized by heat transfer loss/gain coefficients (Damasceno, Rooke, and Goldschmidt 1991).…”

Section: Component Modelsmentioning

confidence: 99%

Transient Simulation of an Air-source Heat Pump under Cycling of Frosting and Reverse-cycle Defrosting

Ma¹,

Kim²,

Braun³

2023

Linköping Electronic Conference Proceedings

View full text Add to dashboard Cite

Frost accumulation is a common but undesired phenomenon for air-source heat pump (ASHP) systems in winter operations. Reverse-cycle defrosting that applies heat to the outdoor coil by reversing the thermodynamic cycle, is one of the predominant means for periodic removal of the accumulated frost. This paper presents a dynamic modeling framework for ASHPs under cycling of frosting and reverse-cycle defrosting operations. A uniform model structure was applied to frost formation and melting models, which were incorporated into the evaporator model, without a need for reinitializing the system when the operating mode switches between heating and defrosting. The developed model was simulated to predict transients of a residential ASHP under multiple cycles of frosting and defrosting operations, and results yielded good agreement with measurements.

show abstract

Section: Component Modelsmentioning

confidence: 99%

Transient Simulation of an Air-source Heat Pump under Cycling of Frosting and Reverse-cycle Defrosting

Ma¹,

Kim²,

Braun³

2023

Linköping Electronic Conference Proceedings

View full text Add to dashboard Cite

show abstract

“…Krishnan [5] evaluated the impact of the four-way reversing valves on the performance of the heat pump air conditioning system and pointed out that the poor performance of the four-way reversing valves could lead to a 5% reduction in the efficiency of the whole system. Damasceno [6] discussed the influence of the four-way reversing valves on the heat pump air conditioning system through a mathematical model in terms of heat transfer, pressure drop and leakage. It was found that the pressure drop loss had the greatest impact on the system performance in the cooling condition, while in the heating condition, the pressure drop loss became the second impact factor.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Effects of Slider Structure on the Reversing Performance of Four-Way Reversing Valve

Zhang

Wang

et al. 2023

Processes

View full text Add to dashboard Cite

Unsmooth reversing is one of the most common faults in the four-way reversing valve of the air conditioning system, and the airflow in the valve chamber and the shape of the slider of the reversing valve are the main factors in unsmooth reversing. In order to study the influence of the airflow in the chamber and the slider shape on the reversing process, the fluid flow in the valve chamber of a four-way reversing valve is obtained using computational fluid dynamics (CFD) simulations, and the influence of the slider structure on slider thrust and resistance of the four-way reversing valve is analyzed. Four-way reversing valves with no-cutting, straight-cutting and arc-cutting sliders are employed to evaluate the reversing characteristics. A pressure measuring device for a four-way reversing valve chamber is designed, which is performed to test the chamber pressure of three different types of sliders of four-way reversing valves. The maximum error of experimental tests and simulations is within 5% of engineering tolerance, so as to verify the reliability of numerical simulation. The resistance-to-thrust ratio of the slider is raised to evaluate the performance of the reversing, which can guide the design of the valve and slider. The results indicate that the chamber pressure and resistance-thrust ratio with the cutting slider are reduced, which is beneficial to the reversing of the four-way reversing valve. Compared with the straight-cutting structure, the arc-cutting slider four-way reversing valve has a more stable reversing process and better comprehensive reversing performance. Results demonstrate that both the straight-cutting structure and arc-cutting structure of the slider can improve the process performance but the arc-cutting slider is better.

show abstract

“…The heat loss on the suction side is most affected by the main material of the four-way reversing valve, followed by the connecting material and valve seat [16]. Four-way reversing valves with different thermal conductivity materials have a significant impact on refrigeration systems [17,18]. They analyzed the results of two materials with different thermal conductivity, stainless steel and copper, and pointed out that compared to copper materials, using stainless steel materials with low thermal conductivity can increase energy efficiency by at least 1% [19].…”

Section: Introductionmentioning

confidence: 99%

Research on Flow-Induced Excitation Characteristics of a Four Way Reversing Valve

Zhang¹,

Wu²,

Yuan³

et al. 2023

Preprint

View full text Add to dashboard Cite

The four-way reversing valve is a key component determining whether a heat pump air conditioning system can work. Studying the four-way reversing valve is of great significance for improving the performance of the heat pump air conditioning system. In this paper, the control equation of the sliding block movement process is constructed to simulate the reversing process of the four-way reversing valve in fluid mechanics, and a detailed study is carried out from the sliding block speed, sliding block acceleration, sliding block force, refrigerant leakage, and other aspects. Research has shown that optimizing the structure of the slider can greatly improve the working performance of the four-way reversing valve. Increasing the height of the slider not only improves the pressure relief ability of the four-way reversing valve and prevents the slider from being damaged by high-pressure gas impact, but also reduces the leakage of refrigerant during the directional process; When reducing the length of the slider, although it will improve the pressure relief capacity of the four-way reversing valve, it also increases the amount of refrigerant leakage. The research results provide a theoretical basis and improvement direction for designers to improve the performance of four-way reversing valves.

show abstract

Effects of reversing valves on heat pump performance

Cited by 8 publications

References 1 publication

Transient Simulation of an Air-source Heat Pump under Cycling of Frosting and Reverse-cycle Defrosting

Transient Simulation of an Air-source Heat Pump under Cycling of Frosting and Reverse-cycle Defrosting

Investigation of Effects of Slider Structure on the Reversing Performance of Four-Way Reversing Valve

Research on Flow-Induced Excitation Characteristics of a Four Way Reversing Valve

Contact Info

Product

Resources

About