New Mathematical Model of Solar Flux Radiation for Double-Pitched Roof Surface

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Mohamed Harimi ◽  
Kiam Beng Yeo ◽  
Nordin Othman
Keyword(s):  
Mathematical Model ◽  
Natural Ventilation ◽  
Cooling System ◽  
Point Of View ◽  
Solar Flux ◽  
Passive Cooling ◽  
Proposed Model ◽  
The Difference ◽  
The Impact ◽  
Passive Cooling System

The aim of this research is to simplify an existing model (model-1) of solar flux radiation containing many parameters as compared to a new mathematical model (model-2) using just two independent variables, time and roof's angle of inclination. The impact of the solar radiation on the surface of the roof in Sabah (state of Malaysia) has been examined under different orientations and slopes by means of model-1 at different time of the day. Furthermore, the data of solar flux radiation computed using model-1 has been explored to develop the model-2 from which the correlation coefficient of 0.87 was achieved using regression analysis. It has been proven statistically using the t-test that the difference between the existing model-1 and the proposed model-2 is not significant. The new mathematical model-2 developed can be applied for a double-pitched roof at any given orientation in the area of Sabah only, where the slope of the roof and the local time have to be taken from 0 to 75 degrees and from 7 hrs to 17 hrs, respectively. Additionally, the method used in the derivation of this new model can also be employed for other states of Malaysia as well as other countries. From a technical point of view, the architects or designers can use the proposed model for a quick estimation of solar flux radiation, to identify the type of insulations to be applied under the roof or above the ceiling, as well as the size area of the natural ventilation and the decision-making on the thermal system to be employed, either as an active or a passive cooling system.

scholarly journals Performance evaluation of sub ground passive cooling system with Ecotech software simulation (Case study: Pasio Christi Church at Cibunut, Kuningan, West Java)

2021 ◽  
Vol 878 (1) ◽  
pp. 012006
Author(s):  
I Musdinar ◽  
R A Ardli
Keyword(s):  
Performance Evaluation ◽  
Cooling System ◽  
Passive Cooling ◽  
West Java ◽  
Tropical Regions ◽  
Software Simulation ◽  
Church Building ◽  
The Difference ◽  
Passive Cooling System ◽  
The Church

Abstract The church in Cibunut, Kuningan, West Java has implemented a sub ground passive cooling system in its renovated building in 2018. This sub ground passive cooling system has not been widely applied in tropical regions, however the church is trying to implement it. This system is supported by making air wells and flowing cold air through distribution pipes into the room. Because not many people have implemented this system, performance evaluation through an ecotect software simulation is used to determine the success of the system in cooling the room. The research was carried out with the following steps: (i) Data collection in the form of CAD drawings of Cibunut Church building, (ii) Simulation using ecotect software, and (iii) Analysis of simulation results with thermal comfort standards in the tropics. The results of this study are conclusions from the results of simulations and analyzes, as an illustration in applying of the sub ground passive cooling system. This research helps illustrate the difference between buildings that have not applied sub ground passive cooling and buildings that have applied sub ground passive cooling.

scholarly journals Thermal condition in Semarang Cathedral’s passive cooling system

2018 ◽  
Author(s):  
Augi Sekatia ◽  
Bangun I. R. Harsritanto ◽  
Erni Setyowati ◽  
Gagoek Hardiman
Keyword(s):  
Thermal Condition ◽  
Cooling System ◽  
Passive Cooling ◽  
Passive Cooling System

Numerical Thermal Performance Investigation of an Electric Motor Passive Cooling System Employing Phase Change Materials

2021 ◽  
Author(s):  
Ali Deriszadeh ◽  
Filippo de Monte ◽  
Marco Villani
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Electric Motor ◽  
Phase Change Materials ◽  
Cooling System ◽  
Passive Cooling ◽  
Time Step ◽  
Cooling Performance ◽  
Passive Cooling System ◽  
Change Material

Abstract This study investigates the cooling performance of a passive cooling system for electric motor cooling applications. The metal-based phase change materials are used for cooling the motor and preventing its temperature rise. As compared to oil-based phase change materials, these materials have a higher melting point and thermal conductivity. The flow field and transient heat conduction are simulated using the finite volume method. The accuracy of numerical values obtained from the simulation of the phase change materials is validated. The sensitivity of the numerical results to the number of computational elements and time step value is assessed. The main goal of adopting the phase change material based passive cooling system is to maintain the operational motor temperature in the allowed range for applications with high and repetitive peak power demands such as electric vehicles by using phase change materials in cooling channels twisted around the motor. Moreover, this study investigates the effect of the phase change material container arrangement on the cooling performance of the under study cooling system.

scholarly journals Modeling a Passive Cooling System for Photovoltaic Cells Under Concentration

2007 ◽  
Author(s):  
Allison Gray ◽  
Robert Boehm ◽  
Kenneth W. Stone
Keyword(s):  
Solar Irradiance ◽  
Waste Heat ◽  
Cooling System ◽  
Photovoltaic Cells ◽  
Theoretical Data ◽  
Photovoltaic System ◽  
Passive Cooling ◽  
Cell Temperature ◽  
Worst Case ◽  
Passive Cooling System

Cooling of photovoltaic cells under high intensity solar irradiance is a major concern when designing concentrating photovoltaic systems. The cell temperature will increase if the waste heat is not removed and the cell voltage/power will decrease with increasing cell temperature. This paper presents an analysis of the passive cooling system on the Amonix high concentration photovoltaic system (HCPV). The concentrator geometry is described. A model of the HCPV passive cooling system was made using Gambit. Assumptions are discussed that were made to create the numerical model based on the actual system, the methods for drawing the model is discussed, and images of the model are shown. Fluent was used to compute the numerical results. In addition to the theoretical results that were computed, measurements were made on a system in the field. These data are compared to the theoretical data and differences are calculated. Theoretical conditions that were studied included uniform cell temperatures and worst case weather scenarios, i.e., no wind, high ambient conditions, and high solar irradiance. The performance of the Amonix high concentrating system could be improved if more waste heat were removed from the cell. Now that a theoretical model has been developed and verified, it will be used to investigate different designs and material for increasing the cooling of the system.

scholarly journals Active cooling photovoltaic with IoT facility

2021 ◽  
Vol 12 (3) ◽  
pp. 1494
Author(s):  
Muhammad Nizam Kamarudin ◽  
Sahazati Md. Rozali ◽  
Mohd Saifuzam Jamri
Keyword(s):  
Real Time ◽  
Cooling System ◽  
Solar Panel ◽  
State Of Charge ◽  
Photovoltaic System ◽  
Passive Cooling ◽  
Active Cooling ◽  
Passive Cooling System ◽  
Pv Power Generation ◽  
Sunlight Intensity

Harvesting energy from the sun makes the photovoltaic (PV) power generation a promising technology. To obtain a consistent state of charge (SOC), consistent energy must be harvested and efficiently directed to the battery. Overcharging or undercharging phenomena decreases the lifetime of the battery. Besides, the effect of irradiance toward solar in term of sunlight intensity effects the efficiency and hence, sluggish the SOC. The main problem of the solar panel revealed when the temperature has increased, the efficiency of solar panel will also be decreased. This manuscript reports the finding of developing an automatic active cooling system for a solar panel with a real time energy monitoring system with internet-of-things (IoT) facility. The IoT technology assists user to measure the efficiency of the solar panel and SOC of the battery in real time from any locations. The automatic active cooling system is designed to improve the efficiency of the solar panel. The effectiveness of the proposed system is proven via the analysis of the effect of active cooling toward efficiency and SOC of photovoltaic system. The results also tabulate the comparative studies of active-to-passive cooling system, as well as the effect of cooling towards SOC and efficiency of the solar panel.

scholarly journals KGPMH: A hybrid approach for solving a novel facility location problem

2021 ◽  
Author(s):  
Maryam DehghanChenary ◽  
Arman Ferdowsi ◽  
Fariborz Jolai ◽  
Reza Tavakkoli-Moghaddam
Keyword(s):  
Mathematical Model ◽  
Location Problem ◽  
Hybrid Approach ◽  
Facility Location Problem ◽  
Evaluation Function ◽  
Genetic Approach ◽  
Hub Location ◽  
Hub Location Problem ◽  
Proposed Model ◽  
The Impact

<pre>The focus of this paper is to propose a bi-objective mathematical model for a new extension of a multi-period p-mobile hub location problem and then to devise an algorithm for solving it. The developed model considers the impact of the time spent traveling at the hubs' network, the time spent at hubs for processing the flows, and the delay caused by congestion at hubs with specific capacities. Following the unveiled model, a hybrid meta-heuristic algorithm will be devised that simultaneously takes advantage of a novel evaluation function, a clustering technique, and a genetic approach for solving the proposed model.</pre>

Assessing the impact of agrochemicals on schistosomiasis transmission: A mathematical study

2021 ◽  
pp. 2150049
Author(s):  
Liming Cai ◽  
Peixia Yue ◽  
Mini Ghosh ◽  
Xuezhi Li
Keyword(s):  
Mathematical Model ◽  
Sensitivity Analysis ◽  
Numerical Simulations ◽  
Disease Transmission ◽  
Agricultural Pollution ◽  
Parasitic Disease ◽  
Mathematical Study ◽  
Proposed Model ◽  
Existence And Stability ◽  
The Impact

Schistosomiasis is a snail-borne parasitic disease, which is affecting almost 240 million people worldwide. The number of humans affected by schistosomiasis is continuously increasing with the rise in the use of agrochemicals. In this paper, a mathematical model is formulated and analyzed to assess the effect of agrochemicals on the transmission of schistosomiasis. The proposed model incorporates the effects of fertilizers, herbicides and insecticides on susceptible snails and snail predators along with schistosomiasis disease transmission. The existence and stability of the equilibria in the model are discussed. Sensitivity analysis is performed to identify the key parameters of the proposed model, which contributes most in the transmission of this disease. Numerical simulations are also performed to assess the impact of fertilizers, herbicides and insecticides on schistosomiasis outbreaks. Our study reveals that the agricultural pollution can enhance the transmission intensity of schistosomiasis, and in order to prevent the outbreak of schistosomiasis, the use of pesticides should be controlled.

Noise reduction of enhanced acoustic balconies on a high-rise building block

2021 ◽  
Vol 263 (1) ◽  
pp. 5327-5334
Author(s):  
SK Tang ◽  
Rudolf YC Lee
Keyword(s):  
Noise Reduction ◽  
Natural Ventilation ◽  
Traffic Noise ◽  
Elevation Angle ◽  
Noise Levels ◽  
Indoor Space ◽  
New Device ◽  
Air Inlet ◽  
The Difference ◽  
The Impact

A new device called 'enhanced acoustic balcony' is installed in a new housing estate in Hong Kong. It is intended to help reduce the impact of traffic noise on the residents. This balcony is basically an enlarged form of a plenum window and with three openings. Apart from the outdoor air inlet, there is the balcony door and a side-hung window on the interior balcony wall for natural ventilation of the indoor space. Sound absorption of NRC 0.7 is installed on the balcony ceiling and its sidewall facing the incoming traffic noise and an inclined panel is installed outside the balcony to provide noise screening. A site measurement of its noise reduction is carried out in the present study in a newly completed housing block. A 28 m long loudspeaker array is used as the sound source. The indoor noise levels are measured according to ISO standard. The results show that the difference between indoor and outdoor noise levels in the presence of this balcony form varies over a relatively narrow range between 10 to 13 dBA for an elevation angle from 25 to 60 deg. There is a weak increase of the noise level difference with elevation angle.

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