Advances of Zero Flow Simulation of Air Conditioning Systems using Modelica

Dermont, Pieter; Limperich, Dirk; Wíndahl, Johan; Prölß, Katrin; Kubler, Carsten

doi:10.3384/ecp16124139

Cited by 3 publications

(4 citation statements)

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“…A conventional remedy for this behavior is to replace the singular part with locally non-singular substitute resulting in a finite derivative at the point; this process is often referred to as regularization. According to Dermont et al (2016), a regularized pressure drop correlation is necessary for a complex thermo-fluid model to compute under zero flow conditions. The builtin implementation of power function that employs such regularization for terms in Eq.…”

Section: Figure 1 Staggered Grid Schemementioning

confidence: 99%

“…Simulation of system dynamics under such conditions presents numerical challenges, such as problems with robustness and an attendant increase in simulation time due to direction switching flows. In recognition of these problems, Dermont et al (2016) proposed an approach to improve zero-flow simulation based on a systematic analysis of heat transfer coefficients. Although this approach was shown to increase simulation robustness under (near) zero-flow conditions, the presented use cases ran much slower than real time.…”

Section: Introductionmentioning

confidence: 99%

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Performance Enhancements for Zero-Flow Simulation of Vapor Compression Cycles

Qiao¹,

Laughman²

2023

Linköping Electronic Conference Proceedings

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Models that correctly describe the dynamic behavior of vapor compression cycle at low or zero refrigerant mass flow rates are valuable because they can be used to handle low load, on/off cycling and inactive component conditions. However, low- or zero-flow simulation imposes significant computational challenges because of high frequency oscillations in mass flow. We explore techniques that may be used for improving robustness and performance of low- or zero-flow simulation. Comparisons are conducted to demonstrate the efficacy of the proposed techniques. It is shown that these techniques can result in simulations that are more robustand significantly faster than real-time.

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Section: Figure 1 Staggered Grid Schemementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Performance Enhancements for Zero-Flow Simulation of Vapor Compression Cycles

Qiao¹,

Laughman²

2023

Linköping Electronic Conference Proceedings

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“…The components used in the present investigation have been updated to stream connectors (Franke et al, 2009). The modifications for heat transfer coefficient and pressure drop characteristics as suggested by Dermont et al (2016) have been incorporated. The PCM model is developed for the present investigation and is discussed in detail.…”

Section: Model Developmentmentioning

confidence: 99%

Modeling Heat Pump Recharge of a Personal Conditioning System with Latent Heat Storage

Dhumane

Ling

Aute

et al. 2019

Linköping Electronic Conference Proceedings

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Roving Comforter provides personal cooling in the range of 150 W using vapor compression cycle (VCC) up to 4 hours. During this operation, the condenser heat is stored in a latent heat storage made of phase change material (PCM). This heat needs to be discharged before next cooling operation. A heat pump mode is considered and analyzed for this heat discharge in the present article. The cycle is modeled using CEEEModelicaLibrary, which is a commercial package for complex vapor compression systems. Equations and assumptions involved in modeling some of the components is presented. Programming and modeling decisions for PCM modeling are discussed in detail. A parametric study is conducted with the heat pump system model to identify merits and demerits of operating heat pump cycle at various compressor RPM's.

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“…Dermont et al [19] highlight the fact that simulations involving reversible or zero mass flow rates are challenging for numerical solvers to handle since the solver is required to take very small time steps to ensure convergence. The authors recommend a series of techniques for more robust modelling of such cases.…”

Section: Numerical Treatmentmentioning

confidence: 99%

Development of a Numerical Tool for Dynamic Simulations of Two-Phase Cooling Systems

Bhanot¹,

Dhumane²,

Petagna³

et al. 2019

Int. j. simul. model.

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In this article, the development of a simulation tool for two-phase cooling systems is discussed. The targeted application is modelling of the two-phase pumped loop systems used for Silicon tracking detector cooling at CERN. These systems are similar to vapour compression systems in that the thermal dynamics of such systems are dictated by the two-phase fluid present inside the heat exchangers. To properly account for such dynamics, non-homogenous void fraction based two-phase flow models (used for accurate modelling of vapour compression systems) have been incorporated. The tool has been validated against measurements taken for an R-410A-based residential heat pump unit. Both the heating and cooling mode have been simulated and the results have been compared against measured data. The simulated transients are found to compare well against measured trends. The simulations proceed faster than real-time. The tool shows readiness for use in the design of future detector cooling systems.

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Advances of Zero Flow Simulation of Air Conditioning Systems using Modelica

Cited by 3 publications

References 0 publications

Performance Enhancements for Zero-Flow Simulation of Vapor Compression Cycles

Performance Enhancements for Zero-Flow Simulation of Vapor Compression Cycles

Modeling Heat Pump Recharge of a Personal Conditioning System with Latent Heat Storage

Development of a Numerical Tool for Dynamic Simulations of Two-Phase Cooling Systems

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