Parametric Study of Photovoltaic Thermal Solar Collector Using An Improved Parallel Flow

2020 ◽  
Vol 2 (1) ◽  
pp. 19-24
Author(s):  
Sakhr Mohammed Sultan ◽  
Chih Ping Tso ◽  
Ervina Efzan Mohd Noor ◽  
Fadhel Mustafa Ibrahim ◽  
Saqaff Ahmed Alkaff
Keyword(s):  
Thermal Conductivity ◽  
Energy Balance ◽  
Parametric Study ◽  
Solar Collector ◽  
Parallel Flow ◽  
Operating Conditions ◽  
Balance Equations ◽  
Conductivity Type ◽  
Pv Module ◽  
Sunny Weather

Photovoltaic Thermal Solar Collector (PVT) is a hybrid technology used to produce electricity and heat simultaneously. Current enhancements in PVT are to increase the electrical and thermal efficiencies. Many PVT factors such as type of absorber, thermal conductivity, type of PV module and operating conditions are important parameters that can control the PVT performance. In this paper, an analytical model, using energy balance equations, is studied for PVT with an improved parallel flow absorber. The performance is calculated for a typical sunny weather in Malaysia. It was found that the maximum electrical and thermal efficiencies are 12.9 % and 62.6 %, respectively. The maximum outlet water temperature is 59 oC.

Modelling of the Ventilation Unit for a Stand Alone Solar Collector

2013 ◽  
Vol 330 ◽  
pp. 687-692 ◽  
Author(s):  
Jean Louis Canaletti ◽  
Christian Cristofari ◽  
Gilles Notton
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Energy Balance ◽  
Low Temperature ◽  
Solar Collector ◽  
Main Role ◽  
Balance Equations ◽  
Temperature Heat ◽  
Long Time

The work described in this paper concerns a part of the modelling of a standalone air solar collector producing low temperature heat. The main role of the system is to avoid freezing temperatures and to reduce humidity in a room or in an unoccupied home during a long time, with only solar radiation. In view to dispose an essential sizing tool for this solar collector, we developed a mathematical model based on energy balance equations and on the characteristics of the system. This model allows simulation of the aerolic and thermal behaviour of the solar collector. It was validated using experimental data collected by telemetry in six operating sites. We present here the behaviour model of the ventilation unit part.

The Implementation of the Data Validation Process in a Gas Turbine Performance Monitoring System

2005 ◽  
Author(s):  
Pen-Chung Chen ◽  
Helmer Andersen
Keyword(s):  
Energy Balance ◽  
Performance Measurement ◽  
Gas Turbine ◽  
Mass Flow ◽  
Measurement Data ◽  
Measured Data ◽  
Operating Conditions ◽  
Data Validation ◽  
Balance Equations ◽  
Validation Process

It is an important issue for the power generation industry to minimize maintenance cost; increase plant reliability and availability and enhance equipment performance. Knowing the operating conditions of a gas turbine, engineers can analyze and optimize the process throughout the operation. The accuracy of the performance measurement data is very critical in the gas turbine operation, because it is the foundation of the analysis. To verify the accuracy of measurement data, this paper will present a mathematical approach based on the data validation process. The data validation process is a method for correcting and verifying the measurement data and associated uncertainties by satisfying the different conservation laws like mass balance, energy balance and other related balances. The data validation process will increase the overall accuracy of the measurement data. The procedure of data validation will be illustrated by determining the inlet mass flow of a compressor. For the practical purpose, the measurement data presented in this paper is acquired from a commercial gas turbine plant. The inlet mass flow of compressor can be calculated using multiple mass- and energy balance equations. The result of the comparison of the initial measured data and the validated data will be discussed. This paper will also show that the data validation process can identify serious measurement errors and eliminate the common contradictions among the balance equations. After applying the data validation method on the performance measurement data, plant users will have more confidence to optimize the daily operation. The data validation is an auxiliary method to evaluate the quality of measured data and uncertainties. However, it still cannot replace the accurate and calibrated measurement equipments during the performance test. The data validation approach is used as an auxiliary tool for Alstom’s Plant Monitoring and Diagnostic System (AMODIS) [1], which can optimize plant operation and enhance turbine monitoring in critical areas for early warning.

Effects of Ambipolar Diffusion on Prominence Thread Models

1994 ◽  
Vol 144 ◽  
pp. 315-321 ◽  
Author(s):  
M. G. Rovira ◽  
J. M. Fontenla ◽  
J.-C. Vial ◽  
P. Gouttebroze
Keyword(s):  
Energy Balance ◽  
Transition Region ◽  
Ambipolar Diffusion ◽  
Line Profiles ◽  
Balance Equations ◽  
Model Calculations ◽  
Partial Frequency ◽  
Frequency Redistribution ◽  
Partial Frequency Redistribution ◽  
Theoretical Structure

AbstractWe have improved previous model calculations of the prominence-corona transition region including the effect of the ambipolar diffusion in the statistical equilibrium and energy balance equations. We show its influence on the different parameters that characterize the resulting prominence theoretical structure. We take into account the effect of the partial frequency redistribution (PRD) in the line profiles and total intensities calculations.

The Dynamic Modeling of PEMFC System for Automotive Application

2008 ◽  
Author(s):  
Sanggyu Kang ◽  
Kyoungdoug Min
Keyword(s):  
Energy Balance ◽  
Thermal Management ◽  
Dynamic Modeling ◽  
Management System ◽  
Mass Conservation ◽  
Cell System ◽  
Operating Conditions ◽  
Automotive Application ◽  
Thermal Management System ◽  
Control Volumes

Water and thermal management are crucial factors in determining the performance of PEMFC for automotive application. In order to investigate the effect of cell humidity and temperature on the performance of PEMFC, a dynamic model of a PEMFC system for automotive application has been developed by using Matlab/Simulink®. The model is composed of a PEM unit cell, membrane humidifier, and thermal management system (TMS). At first, fuel and air are well hydrated by the shell and tube humidifier, then humidified fuel and air flow into the PEMFC for electrochemical reaction. PEMFC temperature was maintained at a constant level by the thermal management system. The active area of PEM model is 240 cm2. The cell was discretized into several control volumes in the through-plane to resolve energy balance and species diffusion. The membrane humidifier model is also discretized into three control volumes in the through-plane to resolve the mass conservation and energy balance. Fuel and air are hydrated by the diffusion of the water through the membrane. The thermal management system consists of radiator, fan and pump. De-ionized water cools down the temperature of PEMFC. In order to validate the model, the model was compared with a corresponding experiment. Comparison shows that simulation results are in good agreement with experiments. And the dynamic response of PEMFC with regard to the change of current was also investigated. The model is useful to elucidate the relationships between operating conditions such as air relative humidity, temperature, etc. It is expected that this dynamic modeling of PEMFC system can contribute to the design optimization of PEM fuel cell system for vehicle application.

The Efficiency of Tidal Fences: A Brief Review and Further Discussion on the Effect of Wake Mixing

2013 ◽  
Author(s):  
Takafumi Nishino ◽  
Richard H. J. Willden
Keyword(s):  
Energy Balance ◽  
Theoretical Investigation ◽  
Three Dimensional ◽  
Physical Factors ◽  
Balance Equations ◽  
Order Model ◽  
Near Wake ◽  
New Model ◽  
Actuator Disk ◽  
Limiting Efficiency

Recent discoveries on the limiting efficiency of tidal fences are reviewed, followed by a new theoretical investigation into the effect of wake mixing on the efficiency of ‘full’ tidal fences (i.e. turbines arrayed regularly across an entire channel span). The new model is based on the momentum and energy balance equations but includes several unclosed terms, which depend on the actual (three-dimensional) characteristics of turbine near-wake mixing and therefore need to be modelled empirically. The new model agrees well with three-dimensional actuator disk simulations when those unclosed terms are assessed based on the simulations themselves, suggesting that this low-order model could serve as a basis to analyse how various physical factors (such as the design of turbines) affect the limiting efficiency of tidal fences via changes in those terms describing the characteristics of turbine near-wake mixing. Also discussed is the effect of wake mixing on the efficiency of ‘partial’ tidal fences.

Characteristics of Flame Bases for V-Gutters Stabilized Premixed Flames

2013 ◽  
Author(s):  
Fan Gong ◽  
Yong Huang
Keyword(s):  
Thermal Conductivity ◽  
Temperature Gradient ◽  
Equivalence Ratio ◽  
Premixed Flames ◽  
Flame Stabilization ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Heat Conducting ◽  
Inlet Velocity ◽  
The Impact

The objective of this work is to investigate the flame stabilization mechanism and the impact of the operating conditions on the characteristics of the steady, lean premixed flames. It’s well known that the flame base is very important to the existence of a flame, such as the flame after a V-gutter, which is typically used in ramjet and turbojet or turbofan afterburners and laboratory experiments. We performed two-dimensional simulations of turbulent premixed flames anchored downstream of the heat-conducting V-gutters in a confined passage for kerosene-air combustion. The flame bases are symmetrically located in the shear layers of the recirculation zone immediately after the V-gutter’s trailing edge. The effects of equivalence ratio of inlet mixture, inlet temperature, V-gutter’s thermal conductivity and inlet velocity on the flame base movements are investigated. When the equivalence ratio is raised, the flame base moves upstream slightly and the temperature gradient dT/dx near the flame base increases, so the flame base is strengthened. When the inlet temperature is raised, the flame base moves upstream very slightly, and near the flame base dT/dx increases and dT/dy decreases, so the flame base is strengthened. As the V-gutter’s thermal conductivity increases, the flame base moves downstream, and the temperature gradient dT/dx near the flame base decreases, so the flame base is weakened. When the inlet velocity is raised, the flame base moves upstream, and the convection heat loss with inlet mixture increases, so the flame base is weakened.

scholarly journals Improving the quality of alumina-containing sinter using water-cooled furnace shell

2012 ◽  
Vol 44 (3) ◽  
pp. 281-286
Author(s):  
A.V. Aleksandrov ◽  
V.V. Aleksandrov
Keyword(s):  
Thermal Conductivity ◽  
Steady State ◽  
Heat Exchange ◽  
Energy Balance ◽  
Cold Water ◽  
Sintering Temperature ◽  
Radiant Heat ◽  
Thermal Processes ◽  
Technical Solutions

This article deals with the use of computer modeling to develop technical solutions to ensure better quality of alumina-containing sinter. The simulation accounted for the influence of the feed materials on the thermal processes in the furnace. The energy balance (including thermal conductivity, heat convection and radiant heat exchange) was solved assuming steady state. A good correlation was observed for the actual and calculated temperatures of the solids and gases, with less than 15% discrepancy. Using the model of the furnace investigated the possibility of lowering the temperature of sintering by removing heat from the outside of the furnace shell. To reduce the sintering temperature to 1000 ?C length of the refractory lined steel is 5 m, the height of the lining should not exceed - 0.06 m, the required rate of cold water - 54.7 m3/h

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