scholarly journals Insulation Performance Comparison of Curtain Wall Systems with Existing Pipe Frames and Truss-Shaped Insulation Frames

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4682
Author(s):  
Bo-Hye Choi ◽  
Seung-Yeong Song
Keyword(s):  
Surface Temperature ◽  
Heat Loss ◽  
Three Dimensional ◽  
Performance Comparison ◽  
Base Case ◽  
Loss Reduction ◽  
Curtain Wall ◽  
Thermal Bridging ◽  
Steady State Heat Transfer ◽  
Insulation Performance

The purpose of this study was to compare insulation performance between a base case that applied the existing steel pipe frame and an alternative case that reduced thermal bridging by applying a truss-shaped insulation frame (TIF) to a back frame type curtain wall. Insulation performance was compared by obtaining the effective U-factor and the lowest indoor surface temperature through a three-dimensional steady-state heat transfer simulation. In addition, mock-up tests were performed to compare the U-factors of the base case and alternative case. The simulation results showed that the effective U-factor of the alternative case was 36% lower than in the base case, a significant heat loss reduction. The lowest indoor surface temperature of the alternative case was 0.5 °C higher than in the base case, showing that the surface condensation risk also decreased. In the mock-up test results, the alternative case U-factor was 33% lower than in the base case, confirming the associated large heat loss reduction. For the base case, both the effective U-factor by simulation and the U-factor by the mock-up test were much higher than the design U-factor according to the Korean Design Standard, which neglects thermal bridging, indicating a significantly increased heat loss caused by this factor. For the alternative case, however, both U-factors were similar to the design U-factor.

The Research of Warmth Retention Property of Non-Woven Wadding

2011 ◽  
Vol 197-198 ◽  
pp. 1708-1711
Author(s):  
Cheng Qian
Keyword(s):  
Heat Loss ◽  
Air Permeability ◽  
Loss Reduction ◽  
Warmth Retention

Nowadays in the market, there are many kinds of warm retention materials. Although each material has its own heat loss reduction, there should be methods for evaluating the warmth properties and giving out reliable results. In this paper, the warmth retention properties of three typical non-woven wadding were studied. On the basis of four warming related tests and analyses, the conclusions were got that after filming, because of existence of motionless air, their warmth retention properties increase obviously. In the same time, the air permeability of the three non-woven wadding decrease clearly because of the film on the wadding surface which obstructs air from flowing easily.

Optimization of heat loss reduction from the gas holder: Analytical study

1987 ◽  
Vol 27 (2) ◽  
pp. 127-131 ◽  
Author(s):  
G.N. Tiwari ◽  
Y.P. Yadav ◽  
A. Srivastava
Keyword(s):  
Heat Loss ◽  
Analytical Study ◽  
Loss Reduction

scholarly journals The Challenge of the Urban Compact Form: Three-Dimensional Index Construction and Urban Land Surface Temperature Impacts

2021 ◽  
Vol 13 (6) ◽  
pp. 1067
Author(s):  
Han Yan ◽  
Kai Wang ◽  
Tao Lin ◽  
Guoqin Zhang ◽  
Caige Sun ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Urban Form ◽  
Three Dimensional ◽  
Compact Form ◽  
Landsat 8 ◽  
Driving Mechanism ◽  
Building Density ◽  
Building Height

Cities are growing higher and denser, and understanding and constructing the compact city form is of great importance to optimize sustainable urbanization. The two-dimensional (2D) urban compact form has been widely studied by previous researchers, while the driving mechanism of three-dimensional (3D) compact morphology, which reflects the reality of the urban environment has seldom been developed. In this study, land surface temperature (LST) was retrieved by using the mono-window algorithm method based on Landsat 8 images of Xiamen in South China, which were acquired respectively on 14 April, 15 August, 2 October, and 21 December in 2017, and 11 March in 2018. We then aimed to explore the driving mechanism of the 3D compact form on the urban heat environment (UHE) based on our developed 3D Compactness Index (VCI) and remote sensing, as well as Geo-Detector techniques. The results show that the 3D compact form can positively effect UHE better than individual urban form construction elements, as can the combination of the 2D compact form with building height. Individually, building density had a greater effect on UHE than that of building height. At the same time, an integration of building density and height showed an enhanced inter-effect on UHE. Moreover, we explore the temporal and spatial UHE heterogeneity with regards to 3D compact form across different seasons. We also investigate the UHE impacts discrepancy caused by different 3D compactness categories. This shows that increasing the 3D compactness of an urban community from 0.016 to 0.323 would increase the heat accumulation, which was, in terms of satellite derived LST, by 1.35 °C, suggesting that higher compact forms strengthen UHE. This study highlights the challenge of the urban 3D compact form in respect of its UHE impact. The related evaluation in this study would help shed light on urban form optimization.

A CFD-Based Parametric Study on Modification of Discrete Sister Holes Location for the Film Cooling Flow

2014 ◽  
Author(s):  
Siavash Khajehhasani ◽  
Bassam Jubran
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Base Case ◽  
Spanwise Direction ◽  
Cooling Performance ◽  
Cooling Flow ◽  
Lift Off ◽  
The Individual

A numerical study on the effects of sister holes locations on film cooling performance is presented. This includes the change of the location of the individual discrete sister holes in the streamwise and spanwise directions, where each one of these directions includes 9 different locations, The simulations are performed using three-dimensional Reynolds-Averaged Navier Stokes analysis with the realizable k–ε model combined with the standard wall function. The variation of the sister holes in the streamwise direction provides similar film cooling performance as the base case for both blowing ratios of 0.5 and 1. On the other hand, the spanwise variation of the sister holes’ location has a more prominent effect on the effectiveness. In some cases, as a result of the anti-vortices generated from the sister holes and the repositioning of the sister holes in the spanwise direction, the jet lift-off effect notably decreases and more volume of coolant is distributed in the spanwise direction.

scholarly journals Three-dimensional cellular premixed flames generated by hydrodynamic and diffusive-thermal instabilities (Effects of unburned-gas temperature and heat loss)

2019 ◽  
Vol 85 (879) ◽  
pp. 19-00274-19-00274
Author(s):  
Satoshi KADOWAKI ◽  
Masato NOGAMI ◽  
Thwe Thwe Aung ◽  
Toshiyuki KATSUMI ◽  
Wataru YAMAZAKI ◽  
...  
Keyword(s):  
Heat Loss ◽  
Premixed Flames ◽  
Three Dimensional ◽  
Gas Temperature

Research on Simulation of Operation of DSG Collectors Based on Analysis of Scientific Materials

2011 ◽  
Vol 282-283 ◽  
pp. 710-715 ◽  
Author(s):  
Teng Gao ◽  
Jun Zhao ◽  
Bin Yang ◽  
Fu Wang
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Energy Balance Equation ◽  
Basic Program ◽  
Transfer Model ◽  
Fluid Temperature ◽  
Steam Generation ◽  
Collector Efficiency ◽  
Steady State Heat Transfer ◽  
Fluid Parameters

In this paper, a direct steam generation (DSG) collector is researched. To determinate the DSG collector efficiency, a simplified heat loss correlation is applied. A one-dimensional steady state heat transfer model and an energy balance equation for DSG collector are developed. A Visual basic program coupled with fluid parameters is compiled to compute fluid temperature, heat transfer coefficient and heat loss along the absorber tube by iterations for given accuracy. The variation trends of many kinds of fluid parameters along the absorber tube are revealed. The effect of length of dry steam region on collector efficiency is accounted for also.

Heat transfer of three-dimensional micropolar fluid on a Riga plate

2020 ◽  
Vol 98 (1) ◽  
pp. 32-38 ◽  
Author(s):  
S. Nadeem ◽  
M.Y. Malik ◽  
Nadeem Abbas
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Differential Equations ◽  
Surface Temperature ◽  
Ordinary Differential Equations ◽  
Nonlinear Partial Differential Equations ◽  
Three Dimensional ◽  
Nonlinear Ordinary Differential Equations ◽  
Exponential Order ◽  
Riga Plate

In this article, we deal with prescribed exponential surface temperature and prescribed exponential heat flux due to micropolar fluids flow on a Riga plate. The flow is induced through an exponentially stretching surface within the time-dependent thermal conductivity. Analysis is performed inside the heat transfer. In our study, two cases are discussed here, namely prescribed exponential order surface temperature (PEST) and prescribed exponential order heat flux (PEHF). The governing systems of the nonlinear partial differential equations are converted into nonlinear ordinary differential equations using appropriate similarity transformations and boundary layer approach. The reduced systems of nonlinear ordinary differential equations are solved numerically with the help of bvp4c. The significant results are shown in tables and graphs. The variation due to modified Hartman number M is observed in θ (PEST) and [Formula: see text] (PEHF). θ and [Formula: see text] are also reduced for higher values of the radiation parameter Tr. Obtained results are compared with results from the literature.

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