Coupling indoor airflow, HVAC, control and building envelope heat transfer in the Modelica<i>Buildings</i>library

Wetter, Michael; Tian, Wei; Li, Dan; Jin, Mingang; Chen, Qingyan

doi:10.1080/19401493.2015.1062557

Cited by 46 publications

(16 citation statements)

References 14 publications

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“…However, at present, it is not possible to conduct a full-scale real-time CFD simulation due to limitations in the computational and storage capacities. Consequently, most of the integrated building energy and airflow simulations conduct a limited number of steady-state CFD airflow simulations, allowing for the assessment of building energy performance [35]. This study relied on performing CFD simulations at representative times of the year.…”

Section: One-way Coupling Strategymentioning

confidence: 99%

Quantifying Impacts of Urban Microclimate on a Building Energy Consumption—A Case Study

et al. 2019

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This paper considered an actual neighborhood to quantify impacts of the local urban microclimate on energy consumption for an academic building in College Park, USA. Specifically, this study accounted for solar irradiances on building and ground surfaces to evaluate impacts of the local convective heat transfer coefficient (CHTC), infiltration rate, and coefficient of performance (COP) on building cooling systems. Using computational fluid dynamics (CFD) allowed for the calculation of local temperature and velocity values and implementation of the local variables in the building energy simulation (BES) model. The discrepancies among the cases with different CHTCs showed slight influence of CHTCs on sensible load, in which the maximum variations existed 1.95% for sensible cooling load and 3.82% for sensible heating load. The COP analyses indicated windward wall and upstream roof are the best locations for the installation of these cooling systems. This study used adjusted infiltration rate values that take into account the local temperature and velocity. The results indicated the annual cooling and heating energy increased by 2.67% and decreased by 2.18%, respectively.

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Section: One-way Coupling Strategymentioning

confidence: 99%

Quantifying Impacts of Urban Microclimate on a Building Energy Consumption—A Case Study

et al. 2019

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“…As another reference, we also conducted the corresponding FFD simulation for each case. The FFD code we used was the one implemented in the Modelica Buildings Library [22] through the research of coupling FFD with Modelica [23]. This FFD code uses the laminar viscosity, first-order time splitting method for solving the equations, and linear semilagrangian scheme for the convection term instead of the high-order hybrid interpolation scheme [11] for the consideration of speed performance.…”

Section: Performance Evaluation Of Sfdmentioning

confidence: 99%

A state-space method for real-time transient simulation of indoor airflow

Wang

Pan

Zhu

et al. 2017

Building and Environment

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Inhomogeneous airflow distribution is common in air-conditioned rooms, especially the large open spaces. To evaluate the thermal comfort of such space, or the control performance of the Heating, Ventilation, and Air Conditioning (HVAC) systems in an efficient way, one will need a fast prediction method to simulate the airflow and temperature distribution. This paper proposes a discrete state-space method, called state-space fluid dynamics (SFD), for the fast indoor airflow simulation. To handle time-varying velocity and temperature field, SFD converts all the governing equations of fluid dynamics into the form of a state-space model. Four typical cases are selected to evaluate both the accuracy and speed of SFD, compared with fast fluid dynamics (FFD), which is another fast airflow simulation program. Results show that SFD is capable of achieving faster-than-real-time airflow simulation with an accuracy similar to FFD. The computing time of SFD is longer than FFD when the time step size is the same. However, SFD can generally produce better results than FFD when the time step size is larger, which allows SFD run faster than FFD.

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“…Recently, there is an emerging interest in using fast fluid dynamics (FFD) for indoor environment simulation instead of full-scale CFD because of superior computational speed of FFD (Zuo et al, 2016). Compared with CFD, however, FFD possesses many limitations.…”

Section: Introductionmentioning

confidence: 99%

Coupled Simulation of a Room Air-conditioner with CFD Models for Indoor Environment

Qiao

Han

Nabi

et al. 2019

Linköping Electronic Conference Proceedings

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Coupled simulation of building energy systems (BES) and computation fluid dynamics (CFD) often focuses on the integration of air handlers with indoor environment, and does not incorporate vapor compression systems into the analysis, yielding inaccurate prediction of building energy consumption. This paper presents a coupled simulation to explore the pull-down performance of a room air conditioning system. The dynamic models of the air-conditioner are constructed in Modelica, whereas the indoor environment is simulated in OpenFOAM. Dynamic characteristics will be compared with different vane angles and airflow modes. Numerical simulations demonstrate that both vane angle and airflow mode exhibit pronounced impact on the pull-down time. Meanwhile, the well-mixed assumption that most of building energy simulation programs are built upon exhibits drastically different dynamic characteristics compared to the detailed CFD model, suggesting that neglecting non-uniform air flow and temperature distributions in buildings might lead to significant errors in control design.

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Coupling indoor airflow, HVAC, control and building envelope heat transfer in the ModelicaBuildingslibrary

Cited by 46 publications

References 14 publications

Quantifying Impacts of Urban Microclimate on a Building Energy Consumption—A Case Study

Quantifying Impacts of Urban Microclimate on a Building Energy Consumption—A Case Study

A state-space method for real-time transient simulation of indoor airflow

Coupled Simulation of a Room Air-conditioner with CFD Models for Indoor Environment

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