Dynamic simulation of electronic expansion valve controlled refrigeration system under different heat transfer conditions

Shang, Yujia; Wu, Ai‐Guo; Fang, Xing; You, Yuwen

doi:10.1016/j.ijrefrig.2016.07.020

Cited by 24 publications

(6 citation statements)

References 21 publications

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“…The EVTMS without BC and motor waste heat recovery, that is, only for cabin thermal comfort, is defined as the baseline EVTMS. The effects of refrigerant charge ( Rc ) and EXV opening ( N EXV ) on HP system performances have been verified. In this section, the effects of Rc and N EXV on the baseline EVTMS performances are studied by experiments, and the optimum Rc and N EXV are determined.…”

Section: Baseline Evtms Resultsmentioning

confidence: 99%

Analyses of an integrated thermal management system for electric vehicles

Tian

2019

Int J Energy Res

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Summary Electric vehicle thermal management system (EVTMS) is a promising method to solve cabin thermal comfort and electronics waste heat. In this paper, an integrated EVTMS combining heat pump, battery cooling, and motor waste heat recovery was proposed. EVTMS performance tests were firstly carried out in the environment chamber with variations of refrigerant charge, electronic expansion valve (EXV) opening, compressor speed, environmental temperature, and waste heat amount. Moreover, the comprehensive energy, exergy, and thermo‐economy analyses for EVTMS were performed based on the experimental results. The results demonstrate that the optimum refrigerant charge for baseline EVTMS is 810 g, and the optimum EXV opening is in the range of 70% to 90%. Accordingly, the percentage of cooling capacity reduction (PCCR) and the percentage of waste heat recovery (PWHR) are in the range of 26.3% to 32.1% and 18.73% to 45.17%, respectively. The exergy destruction ratio of the scroll compressor and external heat exchanger is more than 80%. With the utilization of the proposed EVTMS, the operation cost per hundred kilometers for heating mode is decreased 20.83% compared with that of positive temperature coefficient heaters.

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Section: Baseline Evtms Resultsmentioning

confidence: 99%

Analyses of an integrated thermal management system for electric vehicles

Tian

2019

Int J Energy Res

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“…The expansion valve regulates and reduces the pressure of the high-temperature refrigerant after it is condensed in the condenser. The mass flow rate of refrigerant through the expansion valve can be expressed by Equation ( 11) [39]: The key to modeling the compressor is to establish the relationship between refrigerant flow rate and frequency of the compressor, which can be described by a fitting curve provided by the manufacturer, derived as shown in Equations ( 4)-( 6) [38]. As expressed in Equations ( 7)-( 10), the water-side heat exchange Q w of the condenser is equal to the heat exchange Q rc of the refrigerant side.…”

Section: Heat Pump Modelingmentioning

confidence: 99%

Operational Strategy of a DC Inverter Heat Pump System Considering PV Power Fluctuation and Demand-Side Load Characteristics

Li,

Lu,

Sun

et al. 2024

Buildings

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With the increase in application of solar PV systems, it is of great significance to develop and investigate direct current (DC)-powered equipment in buildings with flexible operational strategies. A promising piece of building equipment integrated in PV-powered buildings, DC inverter heat pump systems often operate with strategies either focused on the power supply side or on the building demand side. In this regard, the aim of this study was to investigate the operational strategy of a DC inverter heat pump system for application in an office building with a PV power system. Firstly, the PV power fluctuation and demand-side load characteristics were analyzed. Then, a series of heat transfer and heat pump system models were developed. A reference building model was developed for simulating the performance of the system. A control logic of the DC inverter heat pump was proposed with a certain level of flexibility and capability considering both the characteristics of the PV power generation and the demand-side heating load. MATLAB/Simulink 2021 software was used for simulation. The simulation results show that the DC inverter heat pump is able to regulate its own power according to the change signal of the bus voltage such that the DC distribution network can achieve power balance and thus provide enough energy for a room. This study can provide a reference for developing flexible operational strategies for DC inverter heat pump systems. The proposed strategy can also help to improve the systems’ performance when they are applied in buildings with distributed PV systems.

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“…The expansion process is considered to be isenthalpic, and thus the refrigerant mass flow rate across the expansion valve can be written as [27] m ex = A ex C ex 2ρ ex,in (P ex,in − P ex,out ) (10) where C ev is the discharge coefficient of the expansion valve provided by the manufacturer; ρ ev,in is the refrigerant density at the valve inlet, P ev,in and P ev,out are the inlet and outlet pressures of the expansion valve, respectively; and A ev is the effective passage flow area of the expansion valve, which is [28] A ex = φ ex A ex.nm (11) where φ ex is the opening degree of the expansion valve and ranges from 0% to 100%; and A ex is the nominal orifice cross sectional area of the expansion valve.…”

Section: ) Expansion Valvementioning

confidence: 99%