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Experimental Study on Phase Change Materials for Cold Energy Storage System
Xuan-Vien Nguyen,
Thanh-Huy Tran
Issue:
Volume 9, Issue 2, June 2020
Pages:
51-55
Received:
22 March 2020
Accepted:
7 April 2020
Published:
17 April 2020
Abstract: Cold Thermal Energy Storage (CTES) is a technology with a high potential for different cooling applications. Many previous works have investigated energy efficiency of different cold units by applying CTES systems using phase change materials (PCMs). Phase change materials (PCMs) are generally regarded as a promising material for storing thermal energy. This work presents an experimental study on phase change materials for cold storage application. The experimental process of phase-change materials is based on the following chemicals: water, propylene glycol (C3H8O2), glycerin (C3H8O3), parrafin oil (white oil LP-70), and sodium polyacrylate (C3H3NaO2)n. The temperature changes over time as ice charging and discharging the phase-change materials are investigated. At the same time, the work try to analyze the physical and chemical properties of the aforementioned phase-change materials. The results indicate that the discharging process of paraffin and glycol is rapid. As for water and sodium polyacrylate, the discharging time is slower than that of paraffin and glycol. And finally, for glycerin, the loading time is slowest compared to other chemicals, the discharging time is also slowest compared to the other four chemicals. This indicates that the latent heat of glycerin has high value, long melting time and deep ice storage temperature. This is a suitable material for use in cold storage systems as a phase change material.
Abstract: Cold Thermal Energy Storage (CTES) is a technology with a high potential for different cooling applications. Many previous works have investigated energy efficiency of different cold units by applying CTES systems using phase change materials (PCMs). Phase change materials (PCMs) are generally regarded as a promising material for storing thermal en...
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Environmental Impacts Analysis of Mining on the Surrounding Communities: A Case Study of Rutongo Mines Ltd in Rulindo District, Northern Province of Rwanda
Hyacinthe Kazindu,
Christophe Mupenzi,
Abias Maniragaba
Issue:
Volume 9, Issue 2, June 2020
Pages:
56-69
Received:
10 March 2020
Accepted:
1 April 2020
Published:
14 May 2020
Abstract: Mineral exploitation contributes significantly to economic growth and development in most world economies. However, from the detection of minerals to their exploitation, there are a number of procedures and methods applied to attain the main objective of economic growth through the exploitation of natural resources. This study examined some known methods of mineral extraction and their impact on environmental degradation and community resources as well. To achieve this objective, data was collected in the mining zones and its surrounding community. Four (4) communities (Masoro, Ntarabana, Cyinzuzi and Murambi) within Rutongo Mines zone were covered; a total of 100 respondents were contacted for relevant information through questionnaire and interviews. The collected data was analyzed using tools like Microsoft word, Microsoft Excel and Arc GIS. The results from data analysis showed that mining activities depleted environmental resources like soil, water, and vegetation; spatial analysis revealed that 509.12 ha were converted from crop land to bare land between year 2010 and 2018 while 193.12 ha of forest land was converted also to bare land; this land cover change impacted the community resources causing shortage and loss of many assets accessed by them. The finding highlighted remarkable relationship between poor methods in minerals exploitation and environmental degradation. In addition to this, illegal mining contributes to rivers pollution, air pollution and deforestation. Therefore, mitigation measures for environmental protection should be implemented this include soil erosion control measures like radical terraces, reforestation and anti- erosion ditches.
Abstract: Mineral exploitation contributes significantly to economic growth and development in most world economies. However, from the detection of minerals to their exploitation, there are a number of procedures and methods applied to attain the main objective of economic growth through the exploitation of natural resources. This study examined some known m...
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The Effect of Heat Transfer Fluid Velocity on Heat Exchange Efficiency in Cold Energy Storage Tank: A Numerical Simulation Study
Xuan-Vien Nguyen,
Thanh-Hau Nguyen,
Trang-Doanh Nguyen,
Tien-Fu Yang
Issue:
Volume 9, Issue 2, June 2020
Pages:
70-74
Received:
14 April 2020
Accepted:
5 May 2020
Published:
14 May 2020
Abstract: Developing a cold thermal energy storage (CTES) technology is one of the most effective methods to solve energy shortage and environmental pollution all over the world. The current study deals with the modelling and simulation of a cold thermal energy storage tank consisting of an polyvinyl chloride pipe (PVC) heat exchanger partially filled with a phase change material (PCM). Water, as the heat transfer fluid (HTF), flows through the inner tubes and the outer one while propylene glycol as the phase change material fills. This paper focuses on studying the effect of the velocity characteristics on the heat transfer efficiency of polyvinyl chloride pipe (PVC) heat exchanger in cold thermal energy storage system by the numerical simulation. In this paper, the detail of heat transfer performance within the heat exchanger is numerically solved using computational fluid dynamics (CFD), for various velocity as well as different heat transfer for optimal design. Several results of changes in the temperature field at the outlet of the cold thermal energy storage tank are presented when the inlet water velocity changes from 1 m/s to 1.4 m/s. The results indicate that low input water velocity will provide better heat exchange efficiency. However, it is required to make sure that the flow inside the heat exchanger is the turbulent flow because the study uses turbulent flow modules.
Abstract: Developing a cold thermal energy storage (CTES) technology is one of the most effective methods to solve energy shortage and environmental pollution all over the world. The current study deals with the modelling and simulation of a cold thermal energy storage tank consisting of an polyvinyl chloride pipe (PVC) heat exchanger partially filled with a...
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Design and Realization of a Mixed Solar Cooker: Application to the Cooking of the Sorghum Wort
Guy Bertrand Tchaya,
Jean Materne Ango,
Etienne Tchoffo Houdji,
Darmand Roger Djoulde,
Noël Djongyang
Issue:
Volume 9, Issue 2, June 2020
Pages:
75-80
Received:
20 December 2019
Accepted:
7 January 2020
Published:
4 June 2020
Abstract: The depletion of fossil energy and his consumption in cooking as the use of firewood are contributing to increase the problem of climate change. It is urgent to find alternative energy sources to take over the situation when the areas are being blessed with higher solar energy potential. The present work concerns design and realization of a mixed solar cooker. It consists of a parabolic reflector of 1m diameter and 0.24m focal point and a box type size of 8.064 dm3. The temperature and irradiance measurements were carried out using a pyranometer and PT 100 sensors. The data were recorded using an acquisition unit (ALMEMO 2390). The design was made by a basic theoretical model developed from the heat transfer equations and simulated using MATLAB software. The tests carried out show that without a sun tracking and without regulating, the temperature inside the cooker rises and reaches the maximum of 95.5°C for a day during which the average irradiance is 690.13 W⁄m2. Without temperature regulation and with manual sun tracking, the temperature is not constant and the maximum value obtained in the cooker is 168°C for an average irradiance of 716.86 W⁄m2. The cooking of 2 litres of sorghum wort was carried out through manual temperature regulation of 80°C for 1 hour and 16 minutes under an average irradiance of 555.52 W⁄m2.
Abstract: The depletion of fossil energy and his consumption in cooking as the use of firewood are contributing to increase the problem of climate change. It is urgent to find alternative energy sources to take over the situation when the areas are being blessed with higher solar energy potential. The present work concerns design and realization of a mixed s...
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Estimation of Wind Energy Potential for Two Locations in North-East Region of Nigeria
Abdullahi Ahmed,
Bashir Isyaku Kunya
Issue:
Volume 9, Issue 2, June 2020
Pages:
81-87
Received:
29 February 2020
Accepted:
26 March 2020
Published:
13 July 2020
Abstract: This paper presents an estimation of wind power potential of North East, Nigeria (Bauchi and Maiduguri) on the basis of monthly wind speed data at 10m height from the ground. The data for the locations were collected from Nigeria metrological station, Abuja for the period of (2013-2017). Mean monthly values were used in calculation of Weibull distribution parameters c (scale factor ms-1) and k (shape factor). The Weibull results shows that for Bauchi, the shape factor ranges from 2.86 – 5.96 and scale factor ranges from 2.32ms-1 – 2.54ms-1 while Maiduguri the shape factor ranges from 2.66 – 5.52 and values of scale factor ranges from 4.74ms-1 – 5.89ms-1. It is evident that the maximum average monthly value of wind speed in Bauchi occurs in year 2017 with value of 3.8ms-1 in the month of May while the maximum average wind speed in Maiduguri occurs in year 2013 with value of 8.5ms-1 in the month of December. The probability distribution function f(V) of wind speed, together with the duration function T(V) was evaluated for the period under investigation. From the statistical analysis of distributions, the Weibull distribution was found to have better fittings in the probability distribution functions f(V) and T(V). The value of power density was computed to be 33.47W/m2 (class I) & 374.62W/m2 (class II) and energy density was also computed to be 24.9 kWh/m2 & 278kWh/m2 for both Bauchi and Maiduguri respectively.
Abstract: This paper presents an estimation of wind power potential of North East, Nigeria (Bauchi and Maiduguri) on the basis of monthly wind speed data at 10m height from the ground. The data for the locations were collected from Nigeria metrological station, Abuja for the period of (2013-2017). Mean monthly values were used in calculation of Weibull distr...
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