The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform

Kai Choong Leong - One of the best experts on this subject based on the ideXlab platform.

  • Numerical modeling of a zeolite/water adsorption cooling system with non-constant Condensing Pressure☆
    International Communications in Heat and Mass Transfer, 2008
    Co-Authors: Y. Liu, Kai Choong Leong
    Abstract:

    A new transient two-dimensional model with non-constant Condensing Pressure for a zeolite/water adsorption cooling cycle is proposed in this paper. This numerical model focuses on the heat and mass transfer behaviors in the adsorber and is solved by the control volume method. Due to the heat transfer limitation in the condenser, the simulated Pressure during the isobaric generation phase of the cycle is not constant and will decrease with time. Compared with the model for constant Condensing Pressure, the cycle duration and cycled adsorbate for the base case are increased. Furthermore, the effect of mass flow rate of condenser cooling water on system performance is also investigated. It is found that both COP and SCP increase with an increase in the mass flow rate of cooling water in the condenser.

  • numerical modeling of a zeolite water adsorption cooling system with non constant Condensing Pressure
    International Communications in Heat and Mass Transfer, 2008
    Co-Authors: Y. Liu, Kai Choong Leong
    Abstract:

    A new transient two-dimensional model with non-constant Condensing Pressure for a zeolite/water adsorption cooling cycle is proposed in this paper. This numerical model focuses on the heat and mass transfer behaviors in the adsorber and is solved by the control volume method. Due to the heat transfer limitation in the condenser, the simulated Pressure during the isobaric generation phase of the cycle is not constant and will decrease with time. Compared with the model for constant Condensing Pressure, the cycle duration and cycled adsorbate for the base case are increased. Furthermore, the effect of mass flow rate of condenser cooling water on system performance is also investigated. It is found that both COP and SCP increase with an increase in the mass flow rate of cooling water in the condenser.

Y. Liu - One of the best experts on this subject based on the ideXlab platform.

  • Numerical modeling of a zeolite/water adsorption cooling system with non-constant Condensing Pressure☆
    International Communications in Heat and Mass Transfer, 2008
    Co-Authors: Y. Liu, Kai Choong Leong
    Abstract:

    A new transient two-dimensional model with non-constant Condensing Pressure for a zeolite/water adsorption cooling cycle is proposed in this paper. This numerical model focuses on the heat and mass transfer behaviors in the adsorber and is solved by the control volume method. Due to the heat transfer limitation in the condenser, the simulated Pressure during the isobaric generation phase of the cycle is not constant and will decrease with time. Compared with the model for constant Condensing Pressure, the cycle duration and cycled adsorbate for the base case are increased. Furthermore, the effect of mass flow rate of condenser cooling water on system performance is also investigated. It is found that both COP and SCP increase with an increase in the mass flow rate of cooling water in the condenser.

  • numerical modeling of a zeolite water adsorption cooling system with non constant Condensing Pressure
    International Communications in Heat and Mass Transfer, 2008
    Co-Authors: Y. Liu, Kai Choong Leong
    Abstract:

    A new transient two-dimensional model with non-constant Condensing Pressure for a zeolite/water adsorption cooling cycle is proposed in this paper. This numerical model focuses on the heat and mass transfer behaviors in the adsorber and is solved by the control volume method. Due to the heat transfer limitation in the condenser, the simulated Pressure during the isobaric generation phase of the cycle is not constant and will decrease with time. Compared with the model for constant Condensing Pressure, the cycle duration and cycled adsorbate for the base case are increased. Furthermore, the effect of mass flow rate of condenser cooling water on system performance is also investigated. It is found that both COP and SCP increase with an increase in the mass flow rate of cooling water in the condenser.

H. Asada - One of the best experts on this subject based on the ideXlab platform.

  • Modeling of vapor compression cycles for advanced controls in HVAC systems
    Proceedings of 1995 American Control Conference - ACC'95, 1995
    Co-Authors: Xiangdong He, H. Asada
    Abstract:

    This paper presents a new lumped-parameter model for describing the dynamics of vapor compression cycles. In particular, the dynamics associated with the two heat exchangers, i.e. the evaporator and the condenser, are modeled based on a moving-interface approach by which the position of the two-phase/single-phase interface inside the one-dimensional heat exchanger can be properly predicted. This model relates critical performance outputs, such as evaporating Pressure, Condensing Pressure, and superheat, to actuating inputs including compressor speed, fan speed, and expansion valve opening. In view of regulating multiple performance outputs in modern heat pumps and air conditioning systems, this model is highly useful for the design of multivariable feedback control.

Tengfei Zhang - One of the best experts on this subject based on the ideXlab platform.

  • a general model for two stage vapor compression heat pump systems
    International Journal of Refrigeration-revue Internationale Du Froid, 2015
    Co-Authors: Shuang Jiang, Shugang Wang, Tengfei Zhang
    Abstract:

    Abstract Two-stage vapor compression technology has high potential of performance improvement for cold climate heat pumps, and there are several types of inter-stage configurations that need to be evaluated before making a choice. A general model of these configurations is first derived from a subcooler cycle and then is extended to be capable of evaluating many other inter-stage configurations by employing an “input domain”. The model is solved with a sequential algorithm and an analytical initial solution of the intermediate Pressure is presented. After an experimentally validation with additional calculations of the subcooling parameter, the evaporating and Condensing Pressure, this general model is then used in the performance comparison and analysis of eight different inter-stage configurations. At last, case studies show that, this general model is capable of performing performance comparison among cycles with different types of inter-stage configurations, as well as refrigerant selection and operational analysis.

Xiangdong He - One of the best experts on this subject based on the ideXlab platform.

  • modeling of vapor compression cycles for multivariable feedback control of hvac systems
    Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 1997
    Co-Authors: Xiangdong He, Harry H Asada
    Abstract:

    This paper presents a new lumped-parameter model for describing the dynamics of vapor compression cycles. In particular, the dynamics associated with the two heat exchangers, i.e., the evaporator and the condenser, are modeled based on a moving-interface approach by which the position of the two-phase/single-phase interface inside the one-dimensional heat exchanger can be properly predicted. This interface information has never been included in previous lumped-parameter models developed for control design purpose, although it is essential in predicting the refrigerant superheat or subcool value. This model relates critical performance outputs, such as evaporating Pressure, Condensing Pressure, and the refrigerant superheat, to actuating inputs including compressor speed, fan speed, and expansion valve opening. The dominating dynamic characteristics of the cycle around an operating point is studied based on the linearized model. From the resultant transfer function matrix, an interaction measure based on the Relative Gain Array reveals strong cross-couplings between various input-output pairs, and therefore indicates the inadequacy of independent SISO control techniques. In view of regulating multiple performance outputs in modern heat pumps and air-conditioning systems, this model is highly useful for design of multivariable feedback control.

  • Modeling of vapor compression cycles for advanced controls in HVAC systems
    Proceedings of 1995 American Control Conference - ACC'95, 1995
    Co-Authors: Xiangdong He, H. Asada
    Abstract:

    This paper presents a new lumped-parameter model for describing the dynamics of vapor compression cycles. In particular, the dynamics associated with the two heat exchangers, i.e. the evaporator and the condenser, are modeled based on a moving-interface approach by which the position of the two-phase/single-phase interface inside the one-dimensional heat exchanger can be properly predicted. This model relates critical performance outputs, such as evaporating Pressure, Condensing Pressure, and superheat, to actuating inputs including compressor speed, fan speed, and expansion valve opening. In view of regulating multiple performance outputs in modern heat pumps and air conditioning systems, this model is highly useful for the design of multivariable feedback control.