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Audit of Electricity Generation in University of Lagos, Nigeria
Oluwatosin M. Dada,
Ilesanmi A. Daniyan,
Temitayo M. Azeez,
Olalekan O. Adaramola
Issue:
Volume 5, Issue 2, April 2016
Pages:
29-33
Received:
18 November 2015
Accepted:
29 November 2015
Published:
21 March 2016
Abstract: Electricity is indispensable to a nation’s economic development. In this paper, analysis of energy sources was carried out to ascertain their costs. The selected energy alternatives are PHCN 132 kV/33 kV/11 kV Substation and Captive Cummings Diesel generator. The case study-site was University of Lagos, Akoka located within Lagos, a commercial city in Nigeria. Practical surveys and data collection were carried out from the power house coupled with their load estimation to obtain the total cost of electricity consumed. The results indicate that, on a monthly basis, the university spends about $820,000 on diesel generator and $228,500 on PHCN.The results also show that other alternative energy sources should be included in the overall energy mix in order to minimise the total power cost of the university.
Abstract: Electricity is indispensable to a nation’s economic development. In this paper, analysis of energy sources was carried out to ascertain their costs. The selected energy alternatives are PHCN 132 kV/33 kV/11 kV Substation and Captive Cummings Diesel generator. The case study-site was University of Lagos, Akoka located within Lagos, a commercial city...
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Thermal Properties of (Na0.6K0.4)NO3 Thermal Storage System in the Solid-Solid Phase
Halima Ibrahim ElSaeedy,
Maryam Ayidh Saad Al Shahrani,
Karam Fathy Abd El-Rahman,
Sayed Taha Mohamed Hassan
Issue:
Volume 5, Issue 2, April 2016
Pages:
34-38
Received:
22 February 2016
Accepted:
6 March 2016
Published:
29 March 2016
Abstract: The thermal behaviour for the DTA, DSC and TGA measurements have been carried on the solid phase transformation for the binary eutectic mixture of 60 wt% sodium nitrate (NaNO3) and 40 wt% potassium nitrate (KNO3). Thermal energy storage materials are important for the technology that is applied to reduce cost solar thermal power generation. The NaNO3-KNO3 system is a binary inorganic salt system and it is one of the most promising thermal storage materials. The methods are based on the principle that a change in the physical state of a material is accompanied by the liberation or absorption of heat. The various techniques of thermal analysis are designed for the determination of the enthalpy accompanying the changes in the physical properties of the material. The thermal measurements showed a reversible phase transition at ~114°C during heating process and at ~108°C during cooling process. It has been shown also the presence of thermal hysteresis during this transformation with a magnitude of the hysteresis temperature ~8°C. The thermogravimetery analysis (TGA) indicated that the eutectic system (Na0.6K0.4)NO3 is thermally stable up to the melting point at ≅225°C. This means that the sample under study is structurally stable. DTA measurements were also carried out for the sample at different heating rates of (2, 5, 10, 15 and 20°C/min). Some thermal parameters such as the transition point, enthalpy and the activation energy for the transformation process were estimated at each heating rate. It has been also shown that these parameters are affected by the heating rate. The noticeable effect of heating rate on the thermal parameters means that the heating rate is a main factor to change the thermal interaction potential of the Na and K atoms around the nitrate group (NO3-) during the phase conversion for the eutectic (Na0.6K0.4)NO3 system.
Abstract: The thermal behaviour for the DTA, DSC and TGA measurements have been carried on the solid phase transformation for the binary eutectic mixture of 60 wt% sodium nitrate (NaNO3) and 40 wt% potassium nitrate (KNO3). Thermal energy storage materials are important for the technology that is applied to reduce cost solar thermal power generation. The NaN...
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Prandtl Number Effect of Mixed Convection Heat and Mass Transfer in a Triangular Enclosure with Heated Circular Obstacle
Sayeda Fahmida Ferdousi,
Md. Abdul Alim,
Raju Chowdhury
Issue:
Volume 5, Issue 2, April 2016
Pages:
39-47
Received:
11 January 2016
Accepted:
2 February 2016
Published:
6 April 2016
Abstract: The effect of Prandtl number of mixed convection heat and mass transfer in a triangular enclosure with heated and concentrated circular obstacle is analyzed by solving mass, momentum, energy and concentration balance equations. The left lower middle and right upper middle walls are kept at low temperature and concentration. All others wall are assumed to be adiabatic. The lower wall is moving in the +x direction and all others walls are maintained at no-slip condition. Moreover, Galerkin Weighted Residuals finite element method is applied to solve the governing equations. The study is performed for different values of Prandtl number, Richardson number and buoyancy ratio. A simple transformation is employed to transfer the governing equations into a dimensionless form. The result shows that at high Pr heat transfer rate increase rapidly and at low Pr it increases linearly with the increase of Ri. However, buoyancy ratio and Lewis number plays an important role for the flow, temperature and concentration fields.
Abstract: The effect of Prandtl number of mixed convection heat and mass transfer in a triangular enclosure with heated and concentrated circular obstacle is analyzed by solving mass, momentum, energy and concentration balance equations. The left lower middle and right upper middle walls are kept at low temperature and concentration. All others wall are assu...
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Thermal Analysis and Modelling of Thermal Storage in Solar Water Heating Systems
Samuel Sami,
Jorge Zatarain
Issue:
Volume 5, Issue 2, April 2016
Pages:
48-59
Received:
7 March 2016
Accepted:
13 March 2016
Published:
10 April 2016
Abstract: A numerical mathematical model has been developed to predict the thermal behavior of phase change material during thermal storage in a thermal tank. The model is based upon energy conservation equations and includes fusion of the phase change material. The thermal behavior of the phase change material during charging and discharging have been studied numerically, and analyzed under different conditions. Comparisons were made against experimental data for validation purposes of the predictive model. The model fairly predicted experimental data obtained at various inlet conditions of the phase change material.
Abstract: A numerical mathematical model has been developed to predict the thermal behavior of phase change material during thermal storage in a thermal tank. The model is based upon energy conservation equations and includes fusion of the phase change material. The thermal behavior of the phase change material during charging and discharging have been studi...
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Optical Fiber Daylighting System Featuring Alignment-Free
Ngoc Hai Vu,
Seoyong Shin
Issue:
Volume 5, Issue 2, April 2016
Pages:
60-66
Received:
3 May 2016
Published:
4 May 2016
Abstract: We present a cost-effective optical fiber daylighting system composed of prism and compound parabolic concentrator (P-CPC). Our simulation results demonstrate an optical efficiency of up to 89% when the concentration ratio of the P-CPC is fixed at 100. We have also used a simulation to determine an optimal geometric structure of P-CPCs. Because of the simplicity of the P-CPC structure, a lower-cost mass production process is possible. Our quest for an optimal structure has also shown that P-CPC has high tolerance for input angle of sunlight. The high tolerance allows replacing a highly dual precise active sun-tracking system with a single sun-tracking system as a cost-effective solution. Therefore, our results provide an important breakthrough for the commercialization of optical fiber daylighting systems that are faced with challenges related to high cost.
Abstract: We present a cost-effective optical fiber daylighting system composed of prism and compound parabolic concentrator (P-CPC). Our simulation results demonstrate an optical efficiency of up to 89% when the concentration ratio of the P-CPC is fixed at 100. We have also used a simulation to determine an optimal geometric structure of P-CPCs. Because of ...
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An Environmental Value Model to Examine Recycling and Green Development in the Traditional Chinese Medicine Industry
Zhang Haibo,
Shen Yuan,
Shen Junlong,
Yuan Pan
Issue:
Volume 5, Issue 2, April 2016
Pages:
67-72
Received:
3 May 2016
Published:
4 May 2016
Abstract: Green development is a new model of development for China's economy to create a new normal by transforming and upgrading the TCM industry. A green TCM industry must solve the problems of three wastes because wastes generated from processing Chinese medical material (CMM) resources seriously pollutes the ecological environment and puts pressure on the environment. From the environmental value model and green economy theory, this study explains the social value of the environment, clarifies the social costs of TCM resources that create negative externalities from waste generated in the TCM industry. This study on the internal mechanism of external effects and discussion of the green economy model and use of green technology to recycle TCM waste proposes an economic network model to promote the use of technology to reuse TCM waste in a green network of industries.
Abstract: Green development is a new model of development for China's economy to create a new normal by transforming and upgrading the TCM industry. A green TCM industry must solve the problems of three wastes because wastes generated from processing Chinese medical material (CMM) resources seriously pollutes the ecological environment and puts pressure on t...
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A Novel Technique to Design Flat Fresnel Lens with Uniform Irradiance Distribution
Pham Thanh Tuan,
Vu Ngoc Hai,
Seoyong Shin
Issue:
Volume 5, Issue 2, April 2016
Pages:
73-82
Received:
4 May 2016
Published:
5 May 2016
Abstract: In this paper, we propose a novel technique to design flat Fresnel lens to achieve big concentration ratio, high uniform irradiance distribution while keeping F-number small using both refraction and total internal reflection (TIR) phenomena. Also, this method can be used to design concentrated photovoltaic (CPV) system without secondary optics lens (SOE). In this technique, Fresnel lens is constructed by many prisms, which are built by ideal Cartesian oval. The design process of Fresnel lens was performed using Matlab program. Ray tracing technique has been used to optimize the structure of lens using LightToolsTM software. The simulation results have been shown that Fresnel lens has a good optical property such asconcentration ratio is 2500x, F-number =0.4, and high uniform irradiance distribution.
Abstract: In this paper, we propose a novel technique to design flat Fresnel lens to achieve big concentration ratio, high uniform irradiance distribution while keeping F-number small using both refraction and total internal reflection (TIR) phenomena. Also, this method can be used to design concentrated photovoltaic (CPV) system without secondary optics len...
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Numerical Analysis of Thermosyphon Solar Water Heaters
Samuel Sami,
Edwin Marin,
Jorge Rivera
Issue:
Volume 5, Issue 2, April 2016
Pages:
83-89
Received:
26 January 2016
Accepted:
3 February 2016
Published:
11 May 2016
Abstract: This paper presents the modeling and simulation as well as validation of a natural circulation closed thermosyphon glass tube solar collector water heater. Energy conservation equations for the heat transfer fluid flow and the storage tank were written in finite-difference form, integrated and solved to yield the characteristics of the thermosyphon system at different solar insolations and water mass flow rate conditions as well as water temperatures. Comparison between experimental data and numerical prediction of the proposed showed that the model predicted fairly the evacuation of storage tank temperature at various initial temperature of the water at the storage tank.
Abstract: This paper presents the modeling and simulation as well as validation of a natural circulation closed thermosyphon glass tube solar collector water heater. Energy conservation equations for the heat transfer fluid flow and the storage tank were written in finite-difference form, integrated and solved to yield the characteristics of the thermosyphon...
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