Study of Effect of Thermal Diffusivity on Ground Temperature for Malaysian Climate

2014 ◽  
Vol 554 ◽  
pp. 301-306 ◽  
Author(s):  
Taib Mohd Yusof ◽  
Shahrani Anuar ◽  
Hassan Ibrahim
Keyword(s):  
Thermal Diffusivity ◽  
Empirical Equation ◽  
Electricity Consumption ◽  
Ground Temperature ◽  
Passive Cooling ◽  
Ground Heat Exchanger ◽  
Application Analysis ◽  
Main Input ◽  
Local Weather ◽  
Temperature Amplitude

Ground has been proven that it is able to supply cooling and heating resulting in significant reduction of electricity consumption. This paper discusses potential of ground towards implementation of ground thermal storage by using ground heat exchanger (GHE) to supply passive cooling for any application. Analysis has been conducted based on empirical equation from conduction heat transfer for depth up to 6 m and thermal diffusivity from 0.04 to 0.1 m2/day. The main input parameters were obtained from local weather station for three consecutive years. The results showed that significant reduction of temperature occur at depth below than 2.0 m in which cooling can be supplied constantly throughout the year. Temperature amplitude also gets attenuated relatively with depth in which amplitude less than 1°C occur at depth more than 4 m for thermal diffusivity 0.04 m2/day. In addition, thermal diffusivity plays important role in determining ground temperature variation. It has been obtained that the temperature amplitude significantly increase when the thermal diffusivity increase. Therefore, this paper had suggested that the application of GHE should be placed in condition of thermal diffusivity 0.06 m2/day and below.

scholarly journals Comprehensive Studies of the Processes of the Molecular Transfer of the Momentum, Thermal Energy and Mass in the Nutrient Media of Biotechnological Industries

2022 ◽  
Vol 9 (1) ◽  
pp. 18
Author(s):  
Aleksandr G. Novoselov ◽  
Sergei A. Sorokin ◽  
Igor V. Baranov ◽  
Nikita V. Martyushev ◽  
Olga N. Rumiantceva ◽  
...  
Keyword(s):  
Thermal Diffusivity ◽  
Dynamic Viscosity ◽  
Empirical Equation ◽  
Molecular Diffusion ◽  
Transport Coefficients ◽  
Molecular Transport ◽  
Rolling Ball ◽  
Molecular Transfer ◽  
Exchange Processes ◽  
Different Temperatures

This article puts forward arguments in favor of the necessity of conducting complex measurements of molecular transport coefficients that quantitatively determine the coefficients of dynamic viscosity, thermal diffusivity and molecular diffusion. The rheological studies have been carried out on the viscometers of two types: those with a rolling ball (HÖPPLER® KF 3.2.), and those with a rotary one (Rheotest RN 4.1.). The thermophysical studies have been performed using the analyzer Hot Disk TPS 2500S. The measurements have been taken in the temperature range of 283 to 363 K. The concentration of dry substances has varied from 16.2 to 77.7% dry wt. An empirical equation for calculating the density of aqueous solutions of beet molasses has been obtained. The diagrams of the dependence of the dynamic viscosity on the shear rate in the range of 1 s−1 to 500 s−1 at different temperatures have been provided. The diagrams of the dependence of the coefficients of thermal conductivity and thermal diffusivity on the temperature and the concentration of dry substances have been presented, and empirical equations for their calculation have been obtained. The findings can be used for engineering calculations of hydrodynamic and heat-exchange processes in biotechnological equipment.

scholarly journals Field measurement of ground temperatures in Bandung: devices and the results of measurement

2020 ◽  
Vol 200 ◽  
pp. 02009
Author(s):  
Muhammad Nur Fajri Alfata ◽  
Amalia Nurjannah
Keyword(s):  
Temperature Sensor ◽  
Field Measurement ◽  
Ground Temperature ◽  
Passive Cooling ◽  
Temperature Profiles ◽  
Temperature Changes ◽  
Ground Temperatures ◽  
Different Depths ◽  
Measurement Devices ◽  
Main Component

Ground cooling is considered to be one of the passive cooling strategies in buildings although its application is rarely found in Indonesia. Effectiveness of this strategy depend on the ground temperature profiles. Meanwhile, comprehensive data of ground temperature as a basis of design for ground cooling are still rarely found in Indonesia. This research aims to develop the measurement devices for collecting ground temperatures data and to investigate the ground temperatures in different depths (i.e., 1m, 2m, …, 9m). For measurement, an instrumentation system was developed with the main component of Arduino Mega 2560 as microcontroller. T-type thermocouples with diameter of 0, 5mm mounted in the metal cones were used as the temperature sensor and placed at the different depths. The field measurement was conducted from August to November 2019 in Bandung, West Java, Indonesia. This study demonstrated that the developed instrument system had good performance both in measuring and data acquisition. Model equation was developed to predict the ground temperature at certain depth regardless ground materials and humidity level. The results indicated that the ground temperature significantly lower to 5m-depth. However, the reduction of the temperature after 5m was not significant; the deeper the ground, the temperature changes are negligible.

Analysis on variations of ground temperature field and thermal radius caused by ground heat exchanger crossing an aquifer layer

2020 ◽  
Vol 276 ◽  
pp. 115453
Author(s):  
Z.D. Ma ◽  
G.S. Jia ◽  
X. Cui ◽  
Z.H. Xia ◽  
Y.P. Zhang ◽  
...  
Keyword(s):  
Temperature Field ◽  
Heat Exchanger ◽  
Ground Temperature ◽  
Ground Heat Exchanger

scholarly journals Efficiency and area demand of multi-layer ground heat exchanger using phase change of water

2019 ◽  
Vol 282 ◽  
pp. 02027
Author(s):  
Hauke Hirsch ◽  
Hans Petzold ◽  
John Grunewald
Keyword(s):  
Heat Exchanger ◽  
Numerical Simulations ◽  
Heat Pump ◽  
Simulation Software ◽  
Passive Cooling ◽  
Ground Heat Exchanger ◽  
Pump System ◽  
Heat Pump System ◽  
German Standard ◽  
The Impact

We conducted numerical simulations of a heat pump system connected to a horizontal ground heat exchanger (HGHX), using a coupling of the hygro-thermal simulation software DELPHIN with Modelica. The aim was to study the influence of different HGHX sizes and assemblies as well as the impact of passive cooling on the systems efficiency. We found that the required ground area could be reduced by up to 70 % compared to the recommendation of German standard when the pipes are placed in multiple layers. Passive cooling is possible but has a negligible effect on the systems efficiency.

scholarly journals Air Pollution and Post-COVID-19 Work Resumption: Evidence from China

2021 ◽  
Author(s):  
Yu Zheng
Keyword(s):  
Air Pollution ◽  
Fixed Effects ◽  
Early Stage ◽  
Electricity Consumption ◽  
Weather Conditions ◽  
Policy Implications ◽  
Positive Relation ◽  
Industrial Enterprises ◽  
Local Weather ◽  
Work Resumption

Abstract To cope with the coronavirus disease (COVID-19), national or subnational regions have carried out anti-pandemic measures such as locking down, which may improve their air quality. This paper examines the relation between air pollution and work resumption from a novel post-pandemic perspective. Using unique data on detailed industrial electricity consumption in China, this paper doesn't find a positive relation between post-COVID-19 work resumption and air pollution during the early-stage recovery. This result is obtained after controlling for province and date fixed effects, as well as local weather conditions. However, the positive relation is found for a particular subsample of large industrial enterprises and April. This finding indicates that large industrial enterprises may recover first, and the resumption is progressing gradually. Finally, several policy implications are provided, which are essentially helpful for other countries’ post-pandemic recovery.

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