A comparison between finite volume and switched moving boundary approaches for dynamic vapor compression system modeling

Pangborn, Herschel C.; Alleyne, Andrew G.; Wu, Ning

doi:10.1016/j.ijrefrig.2015.01.009

Cited by 59 publications

(26 citation statements)

References 11 publications

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“…As a result, the simulation of the start-up process of the heat pump, which for example starts with the evaporator being totally in the two phase mode and ends with the creation of a superheating zone, is not possible. Switching between various Moving Boundaries implementations, leading to a Switching Moving Boundary model, seems to allow the examination of the heat pump operation during start up and shutdown procedures [65][66][67], but since in this work attention was given mainly to the continuous operation of the cascading hybrid system under varying conditions, the classical but simpler moving boundary models described in [68] by Willatzen et al was employed. In the next section, a general overview of the methodology is presented, while the complete set of equations is included in the Appendices A and B.…”

Section: Heat Exchangers Modelsmentioning

confidence: 99%

Hybrid Adsorption-Compression Systems for Air Conditioning in Efficient Buildings: Design through Validated Dynamic Models

et al. 2019

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Hybrid sorption-compression systems are gaining interest for heating/cooling/ refrigeration purposes in different applications, since they allow exploiting the benefits of both technologies and a better utilization of renewable sources. However, design of such components is still difficult, due to the intrinsic complexity of the systems and the lack of reliable models. In particular, the combination of adsorption-compression cascade unit has not been widely explored yet and there are no simulations or sizing tools reported in the literature. In this context, the present paper describes a model of a hybrid adsorption-compression system, realised in Modelica language using the commercial software Dymola. The models of the main components of the sorption and vapour compression unit are described in details and their validation presented. In addition, the integrated model is used for proving the feasibility of the system under dynamic realistic conditions and an example of the technical sizing that the model is able to accomplish is given.

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Section: Heat Exchangers Modelsmentioning

confidence: 99%

Hybrid Adsorption-Compression Systems for Air Conditioning in Efficient Buildings: Design through Validated Dynamic Models

et al. 2019

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“…More details about the MB method can be found in [3,36]: The differential equations of the working fluid mass conservation, working fluid energy conservation, heat source energy conservation, and tube wall energy conservation are listed in Equations (1)-(4) respectively considering the above assumptions. More details about the FV method can be found in [34]:…”

Section: Condenser and Receiver Modelmentioning

confidence: 99%

“…The expander was replaced with a nozzle model in this paper [34]. The working fluid mass flow rate, the output power of the expander, and the working fluid enthalpy at the outlet of the expander can be described as Equations (12)- (14), respectively:…”

Section: Pump and Expander Modelmentioning

confidence: 99%

Dynamic Performance Comparison of CO2 Mixture Transcritical Power Cycle Systems with Variable Configurations for Engine Waste Heat Recovery

Wang

Tian

et al. 2019

Energies

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Carbon dioxide transcritical power cycle (CTPC) is suitable for engine waste heat recovery owing to its advantages, such as compact construction and high decomposition temperature. In addition, the addition of refrigerant can further improve the performance of pure carbon dioxide (CO2). Because there are limited studies considering the dynamic performance of CTPC systems with CO2 mixture as the working fluid (CMTPC), let alone the dynamic performance comparison of different structures of the CMTPC system, the object of the current work was to compare the dynamic performance, including the off-design performance and dynamic response speed, of four kinds of CMTPC systems, as well as their sensitivity to system input parameters. The dynamic models of four CMTPC systems were established and validated against experimental data, which includes basic CMTPC (B-CMTPC), CMTPC with a preheater (P-CMTPC), CMTPC with a recuperator (R-CMTPC), and CMTPC with both a recuperator and preheater (PR-CMTPC). Based on the dynamic models, the off-design performance and dynamic response speed of four CMTPC systems were compared by changing the engine load. The fluctuation amplitude and response time of a R-CTPC system are the maximum under off-design conditions. Moreover, the sensitivity analysis demonstrates that different output parameters of four CMTPC systems have differing sensitivity to input parameters. It is necessary to pay attention to the more sensitive input parameters under the specific working condition to avoid system damage or unsafe operation.

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“…In a "switched" MB (SMB) model, the governing equations are derived separately for each possible combination of fluid phase zones in the heat exchanger, which are treated as modes of the plant [14]. The model then switches between the set of equations for each mode in order to accurately capture the component behavior across multiple phase flow combinations.…”

Section: Nonlinear Modelsmentioning

confidence: 99%

“…The air inlet temperature to each heat exchanger will be treated as a disturbance signal in this work. A complete derivation of the nonlinear VCS models can be found in [15], and their validation with a 1kW experimental system can be found in [12] and [14].…”

Section: Fig 3 Condenser Modementioning

confidence: 99%

Switched linear control for refrigerant superheat recovery in vapor compression systems

Pangborn

Alleyne

2016

Control Engineering Practice

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Extended durations of liquid refrigerant ingestion by the compressor of a vapor compression system (VCS) can lead to damage or failure of this component. While this can be prevented by inserting an accumulator between the evaporator and compressor, this addition of hardware may be undesirable for applications in which the weight or size of the thermal management system is critical. As an alternative, this paper proposes a switched Linear Quadratic Gaussian (LQG) design to quickly recover the presence of a superheated phase at the exit of the evaporator using feedback control. Stability analysis of the closed-loop switched system is presented, and application of the control approach in both simulation and on an experimental VCS testbed demonstrate the success of the control design.

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A comparison between finite volume and switched moving boundary approaches for dynamic vapor compression system modeling

Cited by 59 publications

References 11 publications

Hybrid Adsorption-Compression Systems for Air Conditioning in Efficient Buildings: Design through Validated Dynamic Models

Hybrid Adsorption-Compression Systems for Air Conditioning in Efficient Buildings: Design through Validated Dynamic Models

Dynamic Performance Comparison of CO2 Mixture Transcritical Power Cycle Systems with Variable Configurations for Engine Waste Heat Recovery

Switched linear control for refrigerant superheat recovery in vapor compression systems

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