A comparison of winter heating demand using a distributed and a point source of heating with mixing ventilation

Kuesters, A.; Woods, Andrew W.

doi:10.1016/j.enbuild.2012.07.045

Cited by 15 publications

(4 citation statements)

References 19 publications

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“…L and M are the grid points numbers in the x and y coordinates, respectively, and , ( ) and , ( ) are the weighting coefficients. The 1 st order weighting coefficients , (1) and , (1) can be determined as follows:…”

Section: Methods Methodologymentioning

confidence: 99%

“…Within the last decades, convection problems in cavities which are combined with internal or external heating have attracted much interest from researchers. The internal flow, according to the natural convection inside cavities, is particularly complex because of the interaction between the thermal boundary layer (near the cavity walls) and other fluid parts, where it has been studied numerically and experimentally due to various practical applications [1][2][3][4][5][6]. According to previous studies, natural convection that is combined with internal or external heating has many applications, such as solar energy collection-Singh and Eames [7], building and ventilation-DeBlois et al [8], cooling of electronic equipment-Bairi et al [9], and nuclear reactors-Tseng et al [10], and in many other applications.…”

Section: Introductionmentioning

confidence: 99%

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An Efficient Numerical Simulation of 2D Natural Convection in an Inclined Cavity with Internal Heat Generation Using Differential Quadrature Method

Alesbe

Aljabair

Jalil

2021

Walailak J Sci & Tech

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Natural laminar convective fluid flow has been simulated inside inclined rectangular cavities with and without internal heat generation for different aspect ratios and inclination angles. The most important basic dimensionless parameters for this problem are the external Rayleigh number (RaE) and the internal Rayleigh number (RaI), where RaE refers to the effects of the differential heating of the side walls and RaI refers to the amount of heat produced internally. Results were obtained for 4 cases with 192 tests: case (1), RaI = 0 without internal source generation, and cases (2, 3, and 4) with internal source generation for RaI = RaE, 10 RaE, and 100 RaE, respectively. In all cases, the parameters of study changed as 103 ≤ RaE ≤106, 0 ≤ RaI ≤ 107, inclination angle from 0 to 60 deg., and aspect ratios of the enclosure from 0.5 to 2. Results were represented graphically for flow and thermal fields as a streamline, isothermal contours, and Nusselt number. The computed results show that the strength of convection currents is measured by the internal energy. Finally, it is illustrated that by using a few grid points and a shorter CPU time for calculation, the present method can produce accurate numerical results. Also, increase in RaI leads to increasing heat transfer rate and its direction out from the cavity at both hot and cold walls. For lower values of RaI, heat transfer diffusion is more prominent, while for higher values of RaI, convection outweighs diffusion. HIGHLIGHTS Natural laminar convective fluid flow inside inclined rectangular cavities with and without internal heat generation for different aspect ratios and inclination angles has been simulated The most important basic dimensionless parameters, the external Rayleigh number (RaE) and the internal Rayleigh number (RaI) are studied DQ method performance was excellent The obtained computational results indicate that the strength of the convection currents depends on the internal energy Accurate numerical results can be obtained by the present method using a few grid points and shorter CPU time for calculation GRAPHICAL ABSTRACT

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Section: Methods Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Efficient Numerical Simulation of 2D Natural Convection in an Inclined Cavity with Internal Heat Generation Using Differential Quadrature Method

Alesbe

Aljabair

Jalil

2021

Walailak J Sci & Tech

View full text Add to dashboard Cite

show abstract

“…In recent years, there have been major advances in the engineering theory of buoyancy ventilation, otherwise known as the art of "emptying a filling box" [50][51][52]. Researchers have solved problems such as how to keep the emptying air from stratifying to save energy on colder days [53,54], how to differentially size openings in a multistorey building according to the vertical pressure gradient [55,56], and how to switch to downdraft mode on hotter days with the help of cooling from a concentrated or distributed source [57][58][59][60] Unlike stochastic wind forces, buoyancy forces can be balanced and harnessed in a stable and continuous feedback loop. Sustaining this loop in temperate weather is straightforward.…”

Section: Thermal Mass and Buoyancy Ventilationmentioning

confidence: 99%

The Optimal Tuning, within Carbon Limits, of Thermal Mass in Naturally Ventilated Buildings

Craig¹

2019

Preprint

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What proportions should a thermally massive building have? How should the thermal mass be distributed? Should the "massing" change with the choice of material? This paper shows how to optimize the physical proportions of a building so that it synchronizes ambient heat exchanges in a natural feedback cycle. An internal mass is thermally coupled with buoyancy ventilation; the cycle is driven by the daily swing of outdoor temperature. Tripling up functions in this way—so that structural materials can reliably cool and power the ventilation for buildings—could help decarbonize the construction industry and provide an effective strategy for adapting to life-threatening heatwaves. Based on harmonic analysis, the method allows designers to thermally tune the form and mass of a building to meet chosen targets for temperature and ventilation in free-running mode. Once the optimal balance of exchange rates is known, design teams can proportionally vary the building height and ventilation openings against the surface area and thickness of an internal thermal mass. The possible permutations are infinite but parametrically constrained, allowing teams to fairly compare the functional and environmental credentials of different construction materials while they produce and evaluate preliminary options for organizing the exterior form and interior spaces of a building. An example study suggests that thin-shell structures of minimum weight, and even timber buildings, may be optimally tuned to produce ample ventilation and temperature attenuation.

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“…Also the stratified flow characteristics are dependent upon the flow parameters and the geometry of the space. A comparison of winter heating demand using a distributed and a point source of heating in the case of constant mixing ventilation was predicted by Kuesters and Woods (2012). They demonstrated that strong two layer stratification was developed in the space, whereas with low ventilation flux or large heat supply the stratification is weak.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Stratified Flow Temperature Profiles in a Fully Insulated Environment

Awad¹,

Olimat²,

Almagableh³

et al. 2014

RJASET

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The aim of the study is to present an analytical model to predict the temperature profiles in thermal stratified environment. Thermal stratification is encountered in many situations. The flow of contaminants and hydrocarbons in environment often get stratified. The prediction of temperature profiles and flow characteristics are essential for HVAC applications, environment and energy management. The temperature profiles in the stratified region are successfully obtained, in terms of flow-operating functions. The analytical model agrees well with the published experimental data as well as the related closed-form solutions, which is helpful for HVAC applications. The model will be further developed and incorporated within a numerical model in order to investigate the flow field characteristics and establish correlations for a wide range of parameters.

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A comparison of winter heating demand using a distributed and a point source of heating with mixing ventilation

Cited by 15 publications

References 19 publications

An Efficient Numerical Simulation of 2D Natural Convection in an Inclined Cavity with Internal Heat Generation Using Differential Quadrature Method

An Efficient Numerical Simulation of 2D Natural Convection in an Inclined Cavity with Internal Heat Generation Using Differential Quadrature Method

The Optimal Tuning, within Carbon Limits, of Thermal Mass in Naturally Ventilated Buildings

Prediction of Stratified Flow Temperature Profiles in a Fully Insulated Environment

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