scholarly journals Transparent Vacuum Insulation Panels

2021 ◽  
Author(s):  
Takao Katsura
Keyword(s):  
Thermal Conductivity ◽  
Low Cost ◽  
Conductivity Measurement ◽  
Test Method ◽  
Total Thickness ◽  
Gas Barrier ◽  
Vacuum Insulation ◽  
Apparent Thermal Conductivity ◽  
Heat Flux Meter ◽  
Insulation Performance

New, low-cost transparent vacuum insulation panels (TVIPs) using structured cores for the windows of existing buildings are proposed. The TVIP is produced by inserting the structured core, the low-emissivity film, and the adsorbent into the transparent gas barrier envelopes. In this chapter, the authors introduce the outlines, the design and thermal analysis method, the performance evaluation (test) method. Firstly, five spacers, namely peek, modified peek, mesh, silica aerogel, and frame, are selected as the structured core. The effective thermal conductivity of TVIPs with five different spacers is evaluated at different pressure levels by applying numerical calculation. The result indicated that TVIPs with frame and mesh spacers accomplish better insulation performance, with a center-of-panel apparent thermal conductivity of 7.0 × 10−3 W/m K at a pressure of 1 Pa. The apparent thermal conductivity is the same as the value obtained by the simultaneous evacuation thermal conductivity measurement applying the heat flux meter method. Furthermore, using a frame-type TVIP with a total thickness of 3 mm attached to an existing window as a curtain decreases the space heat loss by approximately 69.5%, whereas the light transparency decreases to 75%.

scholarly journals Applying Petroleum Pressure Buildup Well Test Procedure on Thermal Response Test—A Novel Method to Improve Accuracy of Thermal Conductivity Determination

2017 ◽  
Author(s):  
Tomislav Kurevija ◽  
Kristina Strpić ◽  
Sonja Koščak-Kolin
Keyword(s):  
Thermal Conductivity ◽  
Test Procedure ◽  
Thermal Response ◽  
Conductivity Measurement ◽  
Test Method ◽  
Test Time ◽  
Testing Time ◽  
Well Test ◽  
Improve Accuracy ◽  
Ground Conductivity

Theory of the Thermal Response Testing (TRT) is a well-known part of sizing process of the geothermal exchange system. Multiple parameters influence accuracy of effective ground thermal conductivity measurement; like testing time, variable power, climate interferences, groundwater effect etc. To improve accuracy of the TRT we introduced procedure to additionally analyze falloff temperature decline after power test. Method is based on a premise of analogy between TRT and petroleum well testing, since origin of both procedures lies in diffusivity equation with solutions for heat conduction or pressure analysis during radial flow. Applying pressure build-up test interpretation technique to the borehole heat exchanger testing, greater accuracy could be achieved since ground conductivity could be obtained from this period. Analysis was conducted on coaxial exchanger with five different power steps, and with both direct and reverse flow regime. Each test was set with 96hr of a classical TRT, followed by 96hr of temperature decline, making it almost 2000 hours of cumulative borehole testing. Results showed that ground conductivity value could vary as much as 25% depending on test time, seasonal period and power fluctuations while thermal conductivity obtained from a falloff period gives more stable values with only 10% value variation.

scholarly journals Experimental Verification of Use of Vacuum Insulating Material in Electric Vehicle Headliner to Reduce Thermal Load

2019 ◽  
Vol 9 (20) ◽  
pp. 4207 ◽  
Author(s):  
Baek ◽  
Lee ◽  
Kim
Keyword(s):  
Thermal Conductivity ◽  
Energy Conditions ◽  
Insulation Material ◽  
Cooling Period ◽  
Vacuum Insulation ◽  
Heating And Cooling ◽  
Cabin Temperature ◽  
Materials Used ◽  
Insulation Performance ◽  
Reduced Surface

In electric vehicles (EVs), the use of high-temperature heat transfer components that effectively block external heat and minimize cooling losses can increase vehicle mileage during heating/cooling operations and improve passenger comfort. In particular, in ensuring high thermal insulation, the car headliner forms an important component for effectively managing environmental heat energy and heating and cooling processes inside the EV. In this study, we have proposed and experimentally verified the use and efficacy of vacuum insulation material in the headliner of EVs to reduce the heat load. The thermal conductivity and air permeability of various conventional insulating and vacuum insulation materials used for the headliner were compared to accurately predict the vacuum insulation material performance. We found that the vacuum insulation material affords reduced surface roughness and thermal conductivity and high formability relative to conventional insulation. We also confirmed consequent improvements in the insulation performance by comparing the characteristics of the proposed vacuum-insulation-material headliner (relative to conventional materials) via prototyping and reliability testing. With the “improved” headliner, in summer, the temperature of the automobile cabin was lowered by 2.8 °C, and the cabin temperature was lowered by 3.9 °C during the cooling period relative to conventional insulators, which proves that the cabin temperature can be maintained at a low value during summer parking or cooling. In winter, the cabin temperature was found to be 7.7 °C higher than that obtained with the conventional insulator, which indicates that the cabin temperature can be maintained higher via reduction in the heat loss (because of using vacuum insulation) under the same heating energy conditions during winter.

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