Study on Evaluation Index of Cold Insulation Performance

2012 ◽  
Vol 516-517 ◽  
pp. 1201-1204
Author(s):  
Hai Qian Zhao ◽  
Zhong Hua Wang ◽  
Xiao Yan Liu ◽  
Zhi Guo Wang

The outer surface temperature of cold insulation structure must be higher than air dew point temperature is stipulated in national standard.But the outer surface temperature of cold insulation structure and air dew point temperature normally wave in a certain range with the change of environmental parameters. In Practical application, it is difficult to determine the relationship between these two temperatures. Functional relationship between the outer temperature, air dew point temperature and environmental temperature or humidity is fitted.The influence of the air temperature and humidity is analyzed. Some suggestions about design and evaluation index of cold insulation are offered based on this research.

2020 ◽  
Author(s):  
Rui Wang

<p>    In this work, the relationship between daily extreme precipitation and temperature is investigated by using rain gauge precipitation data and corresponding the Integrated Global Radiosonde Archive over eastern China during 1998-2012. Eventually, 14 stations are selected to explore the relationship in eastern China (MEC) and southeastern China (SEC). The result shows that daily extreme precipitation intensity increases approximately 7% when near surface temperature increases 1 °C in MEC and SEC, which generally follows Clausius–Clapeyron (CC) rate (CC rate describes the increasing rate of water vapor with temperature). Moreover, the regression slopes for the logarithmic daily extreme precipitation intensity and near surface temperature range from 3% °C<sup>-1</sup> to 9% °C<sup>-1</sup> at the selected stations in MEC and SEC. However, extreme precipitation intensity decreases with near surface temperature when the temperature is higher than 25 °C. That is, the increase of extreme precipitation with near surface temperature performances single peak structure in MEC and SEC. The variation of extreme precipitation and near surface dew point temperature shows the similar pattern in MEC and SEC (The transition dew point temperature is also about 25 °C). Therefore, <strong>it could be deduced that extreme precipitation intensity does not always increase with climate warming in MEC and SEC.</strong> In addition, precipitable water, which corresponds to extreme precipitation event, increases with near surface temperature at CC rate. <strong>It is found that the increase rate of precipitable water with temperature is closer to CC rate than that of extreme precipitation.</strong></p>


MAUSAM ◽  
2022 ◽  
Vol 53 (4) ◽  
pp. 417-424
Author(s):  
SUTAPA CHAUDHURI ◽  
SURAJIT CHATTOPADHYAY

The concept of Multi Layer Perceptron and Fuzzy logic is introduced in this paper to recognize the pattern of surface parameters pertaining to forecast the occurrence of pre-monsoon thunderstorms over Kolkata (22 ° 32¢ , 88 ° 20¢ ).   The results reveal that surface temperature fluctuates significantly from Fuzzy Multi Layer Perceptron (FMLP) model values on thunderstorm days whereas on non-thunderstorm days FMLP model fits well with the surface temperature.   The results further indicate that no definite pattern could be made available with surface dew point temperature and surface pressure that can help in forecasting the occurrence of these storms.


2012 ◽  
Vol 9 (3) ◽  
pp. 3029-3062 ◽  
Author(s):  
Z. Sun ◽  
Q. Wang ◽  
Z. Ouyang ◽  
Y. Yang

Abstract. A modified Priestley-Taylor (P-T) equation was proposed by Venturini et al. (2008) to map actual evapotranspiration (ET) based solely on satellite remote sensing data, involving a parameter based on a scaled temperature between dew point temperature and surface temperature. In this study, however, theoretical analyses and field experimental evidence show that it is hard to obtain this scaled temperature using dew point temperature and surface temperature. This study also presents a new parameterization method using air temperature, surface temperature, and surface temperature of a reference dry surface. The actual ET estimates obtained by means of our proposed parameterization method are validated at a site scale, and a case study is conducted to map actual ET from Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER) images using our proposed method. Results of ground-based validation and a case study of mapping ET using ASTER images indicate that the improvement on the modified P-T equation proposed by Venturini et al. (2008) can contribute to generating reliable actual ET.


Author(s):  
BH Poon ◽  
AW Gorny ◽  
KY Zheng ◽  
WK Cheong

Introduction: The Singapore Armed Forces (SAF) collaborated with the Meteorological Service Singapore (MSS) to study the relationship between weather parameters and the incidents of exertional heat injury (EHI) to mitigate the risk of EHI in a practical manner. Methods: Data from the SAF’s heat injury registry and MSS’ meteorological data from 2012 to 2018 were used to establish a consolidated dataset of EHI incidents and same-day weather parameters rank-ordered in deciles. Poisson regression modelling was used to determine the incidence rate ratios (IRRs) of the EHI, referencing the first decile of weather parameters. Two frames of analysis were performed - the first described the relationship between the weather parameters and the adjusted IRR for the same day (D), and the second described the relationship between the weather parameters and the adjusted IRR on the following day (D+1). Results: For wet-bulb temperature, the IRR on D+1 approximated unity for the first nine deciles but rose to 3.09 at the tenth decile. For dew-point temperature, the IRR on D+1 approximated unity for the first nine deciles but rose to 3.48 at the tenth decile. By designating a single dew-point temperature cut-off at  25.1°C (transition between the ninth and tenth decile), the adjusted IRR on D +1 was 2.26 on days with dew-point temperature  25.1°C,. Conclusion: Integrating the data from the SAF and MSS demonstrated that a dew-point temperature ≥ 25.1°C on D correlates statistically with the risk of EHI on D +1and could be used to supplement the risk mitigation system.


2015 ◽  
Vol 752-753 ◽  
pp. 628-631
Author(s):  
Hana Sevcikova ◽  
Eva Rykalová ◽  
Radek Fabian ◽  
Zdenek Perina ◽  
Marcela Halirova ◽  
...  

Article deals with the issue of mold in masonry structures. Attention was focused on the critical detail at expansion joint. Variants of solved detail are focused on the process of surface temperatures in the structure. This detail needs to be solved because of revitalization of the structure. Isotherms of the critical inner surface temperature and dew point temperature were used for the evaluation of the variants.


2022 ◽  
pp. 1420326X2110564
Author(s):  
Chuanmin Tai ◽  
Guansan Tian ◽  
Wenjun Lei

Condensation is a major issue in the safe operation of utility tunnels. To address the condensation problem, the indoor air temperature, relative humidity (RH) and surface temperature in an urban utility tunnel in Jining were continuously measured, and the condensation conditions were surveyed and analysed. The results indicated that under natural ventilation conditions, the air temperature in the comprehensive cabin varied from 23.4°C to 24.5°C, the RH fluctuated between 86.4% and 95.3%, and the corresponding air dew point temperature (DPT) remained in the range of 22.2°C–22.9°C. The surface temperature of the water supply pipeline ranged from 17.8°C to 18.5°C, which was far lower than the DPT in the tunnel, resulting in serious condensation. A water supply pipeline with an anti-condensation design was developed based on environmental test data. A 25-mm-thick rubber plastic sponge insulation layer was used to thermally insulate the water supply pipeline, preventing further dew condensation. Furthermore, mechanical ventilation had little effect on reducing the RH in the tunnel and may actually cause dew condensation; therefore, a ventilation control mode was proposed in this study. These results are expected to provide basic data for further research and reference for the safe management of utility tunnels.


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