Distributed and non-steady-state modelling of an air cooler

Wang, H. W.; Touber, S.

doi:10.1016/0140-7007(91)90082-r

Cited by 92 publications

(21 citation statements)

References 12 publications

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“…The air side heat transfer coefficient is calculated by Bansal's correlation [13] . Wang's correlation [14] is adopted to estimate the heat transfer coefficient of the refrigerant side.…”

Section: Evaporator Modelmentioning

confidence: 99%

Dynamic simulation and performance investigation of no-frost refrigerator: Part I mathematical model

Su¹,

Chen²,

Zhi-jiu³

et al. 2009

J. Shanghai Jiaotong Univ. (Sci.)

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A dynamic approach for the modeling, simulation and analysis of no-frost Refrigerator (RF) is discussed. In Part I, the complex interactions among the components in the cooling system are analyzed in detail, based on which the modeling simplifications are proposed. Then, the mathematical models for the evaporator, cabinet and duct-fan are presented. The whole system is divided into two subsystems-refrigerant cycling system and air cycling system. In order to simplify the model, two closed-loop systems are broken into the compressor component and the evaporator component, respectively. A general distributed parameter model is employed for evaporator with homogeneous flow to simplify the two-phase evaporating flow region. The z-transfer function model is used to describe the cabinet load. Computational fluid dynamics (CFD) method is employed to obtain the pressure drop and flow rate curve of the duct-fan model. Nomenclature a, ai-Coefficient of the equations A-Area, m 2 b, bi-Coefficient of the equations cp-Specific heat capacity at constant pressure, J/(kg·K) C-Thermal capacity, J/K D-Diameter, m h-Specific enthalpy, J/kg L-Length or thickness, m p-Pressure, Pa qm-Mass flow rate, kg/s Q-Heat transfer rate, W T -Temperature, K u-Velocity, m/s V -Volume, m 3 x-Average mass quality α-Heat convection coefficient, W/(m 2 .K) β-Thermal leakage factor, W/(m.K) η-Length along the air flow direction, m θ-Temperature, ℃ μ-Dynamic viscosity, kg/(m·s) ξ-Length along the tube, m

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“…The air side heat transfer coefficient is calculated by Bansal's correlation [13] . Wang's correlation [14] is adopted to estimate the heat transfer coefficient of the refrigerant side.…”

Section: Evaporator Modelmentioning

confidence: 99%

Dynamic simulation and performance investigation of no-frost refrigerator: Part I mathematical model

Su¹,

Chen²,

Zhi-jiu³

et al. 2009

J. Shanghai Jiaotong Univ. (Sci.)

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“…The local heat transfer coefficient for two-phase flow is calculated from a correlation which is based on the Lockhart-Martinelli parameter [12], in which…”

Section: Heat Transfer Coefficients Inside the Copper Coilmentioning

confidence: 99%

Performance analysis of an air-source heat pump using an immersed water condenser

Huide

et al. 2009

Front. Energy Power Eng. China

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A distributed model of an air-source heat pump (ASHP) system and its experimental setup using an immersed water condenser were presented. Dynamic performance of the ASHP was then evaluated by both simulation and experiment. The results indicated that the system coefficient of performance (COP) decreased as the condenser temperature increased, ranging from 4.41 to 2.32 with the average COP equaling 3.29 during the experiment. Comparisons between simulation results and experimental measurements demonstrated that the model was able to yield satisfactory predictions. Furthermore, temperature profiles of the refrigerant in the evaporator and condenser were also given. This paper provides the theoretical and experimental background for ASHP system optimization and a valuable reference for a solar air-source heat pump water heater when the solar irradiation energy is insufficient on cloudy or rainy days.

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“…According to the parameter lumped characteristics, dynamic models can be classified into 3 models: single-node model [4][5][6][7][8][9][10][11][12] , multi-node model [96][97][98][99][100] and zone model l [94,95] . But we will not address them here because of limited space.…”

Section: Evaporator and Condenser Modelmentioning

confidence: 99%

Simulation technology for refrigeration and air conditioning appliances

Ding

2006

CHINESE SCI BULL

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Simulation technology has been widely used for performance prediction and optimal design of refrigeration and air conditioning appliances. A brief history of simulation technology for refrigeration and air conditioning appliances is reviewed. The models for evaporator, condenser, compressor, capillary tube and thermal insulation layer are summarized, and a fast calculation method for thermodynamic properties of refrigerant is introduced in this paper. The model-based intelligent simulation technology and the simulation technology based on graph theory are also illustrated. Finally, an updated trend of simulation technology development for refrigeration and air conditioning appliances is discussed.The output of refrigeration and air-condition appliances have been increasing rapidly in recent years, especially in China. For example, the annual output of room air conditioners in China is over two thirds of the world total, and the use of air conditioners consumes a lot of electricity, amounting up to 40% of the total electricity consumption in the summer in some cities like Shanghai. Therefore it is an important target to make the design process of refrigeration appliances more efficiently and to improve the product performance. Computer simulation technique is one of valuable means to accomplish this target [1][2][3] .The traditional methods for designing refrigeration and air-conditioning appliances are: to determine the required performance object of a product at first, then to estimate the working conditions, and to calculate the structural parameters at last. This process is very straightforward and quite easy to be understood. But the actual performance of the product might obviously deviate from the required one because there is no accurate model available in the design process. In order to let the products have the desired performance, the processes of developing prototypes, testing their performance and modifying their structures have to be repeated many times, which will increase the cost and delay the completion of the design process.With the computer simulation method, the working conditions and the structural parameters of the product are given, and then the performance is predicted. After predicting the product performance by simulation, the configuration parameters of the product can be evaluated easily. In order to get a group of suitable configuration parameters of the product, the original parameters should be adjusted according to the simulated results, and simulation with the adjusted structural parameters will be done again. The process of modifying the parameters and simulating with modified parameters will be repeated many times until a set of the most suitable parameters is obtained. Such a computation process is an optimization process, which can be implemented by adding some optimization programs or directly operated by users based on their experience. In order to obtain a perfect optimization result quickly, the initial parameters should not be far away from the optimal ones. It is recomme...

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Distributed and non-steady-state modelling of an air cooler

Cited by 92 publications

References 12 publications

Dynamic simulation and performance investigation of no-frost refrigerator: Part I mathematical model

Dynamic simulation and performance investigation of no-frost refrigerator: Part I mathematical model

Performance analysis of an air-source heat pump using an immersed water condenser

Simulation technology for refrigeration and air conditioning appliances

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