A novel multi-layer manifold microchannel cooling system for concentrating photovoltaic cells

2015 ◽  
Vol 89 ◽  
pp. 214-221 ◽  
Author(s):  
Kaijun Yang ◽  
Chuncheng Zuo
Keyword(s):  
Cooling System ◽  
Photovoltaic Cells ◽  
Microchannel Cooling ◽  
Manifold Microchannel

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.

Multiobjective Design Optimization of Microchannel Cooling System Using High Performance Thermal Vias in LTCC Substrates

2013 ◽  
Vol 10 (1) ◽  
pp. 40-47 ◽  
Author(s):  
Aparna Aravelli ◽  
Singiresu S. Rao ◽  
Hari K. Adluru
Keyword(s):  
Heat Transfer ◽  
Design Optimization ◽  
High Performance ◽  
Cooling System ◽  
Optimization Technique ◽  
Optimization Theory ◽  
Thermal Design ◽  
Design Variables ◽  
Microchannel Cooling ◽  
Multiobjective Design

Increased heat generation in semiconductor devices for demanding applications leads to the investigation of highly efficient cooling solutions. Effective options for thermal management include passing of cooling liquid through the microchannel heat sink and using highly conductive materials. In the author's previous work, experimental and computational analyses were performed on LTCC substrates using embedded silver vias and silver columns forming microchannels. This novel technique of embedding silver vias along with forced convection using a coolant resulted in higher heat transfer rates. The present work investigates the design optimization of this cooling system (microheat exchanger) using systems optimization theory. A new multiobjective optimization problem was formulated for the heat transfer in the LTCC model using the log mean temperature difference (LMTD) method of heat exchangers. The goal is to maximize the total heat transferred and to minimize the coolant pumping power. Structural and thermal design variables are considered to meet the manufacturability and energy requirements. Pressure loss and volume of the silver metal are used as constraints. A hybrid optimization technique using sequential quadratic programming (SQP) and branch and bound method of integer programming has been developed to solve the microheat exchanger problem. The optimal design is presented and sensitivity analysis results are discussed.

Modeling Size Effects of a Portable Two-Phase Electronics Cooling Loop With Different Refrigerants

2010 ◽  
Author(s):  
Tom Saenen ◽  
Martine Baelmans
Keyword(s):  
Size Effects ◽  
Cooling System ◽  
Electronics Cooling ◽  
Simple Algorithm ◽  
System Model ◽  
Two Phase ◽  
Component Mixture ◽  
Pressure Losses ◽  
Microchannel Cooling ◽  
Cooling Loop

A one dimensional dynamic system model is developed to accurately simulate a two-phase microchannel electronics cooling loop. This model is based on the single component mixture equations for mass, momentum and energy. These equations are solved numerically using a finite volume method in conjunction with the SIMPLE algorithm. To calculate the pressure losses and heat transfer state of the art empirical correlations are used. Furthermore size effects of a typical microchannel cooling system are investigated with the new model. Special attention is given to the accumulator size and its limitations for portable applications. A simple model to investigate the accumulator size effect on the loop is developed and compared to numerical results obtained from the system model. The influence of various loop parameters and possible improvements are also investigated. Finally the effect of using different coolants is studied.

Computational Analysis of Nanofluid Cooling of High Concentration Photovoltaic Cells

2014 ◽  
Vol 6 (3) ◽  
Author(s):  
Z. Xu ◽  
C. Kleinstreuer
Keyword(s):  
Reynolds Number ◽  
Energy Use ◽  
Volume Fraction ◽  
Cooling System ◽  
Optimal Parameter ◽  
Photovoltaic Cells ◽  
System Efficiency ◽  
Operational Parameters ◽  
High Concentration ◽  
Temperature Range

High concentration photovoltaic devices require effective heat rejection to keep the solar cells within a suitable temperature range and to achieve acceptable system efficiencies. Various techniques have been developed to achieve these goals. For example, nanofluids as coolants have remarkable heat transfer characteristics with broad applications; but, little is known of its performance for concentration photovoltaic cooling. Generally, a cooling system should be designed to keep the system within a tolerable temperature range, to minimize energy waste, and to maximize system efficiency. In this paper, the thermal performance of an Al2O3-water cooling system for densely packed photovoltaic cells under high concentration has been computationally investigated. The model features a representative 2D cooling channel with photovoltaic cells, subject to heat conduction and turbulent nanofluid convection. Considering a semi-empirical nanofluid model for the thermal conductivity, the influence of different system design and operational parameters, including required pumping power, on cooling performance and improved system efficiency has been evaluated. Specifically, the varied system parameters include the nanoparticle volume fraction, the inlet Reynolds number, the inlet nanofluid temperature, and different channel heights. Optimal parameter values were found based on minimizing the system's entropy generation. Considering a typical 200-sun concentration, the best performance can be achieved with a channel of 10 mm height and an inlet Reynolds number of around 30,000, yielding a modest system efficiency of 20%. However, higher nanoparticle volume fractions and lower nanofluid inlet temperatures further improve the cell efficiency. For a more complete solar energy use, a combined concentration photovoltaic and thermal heating system are suggested.

A Numerical Study of Flow and Temperature Maldistribution in a Parallel Microchannel System for Heat Removal in Microelectronic Devices

2012 ◽  
Author(s):  
Manoj Siva ◽  
Arvind Pattamatta ◽  
Sarit Kumar Das
Keyword(s):  
Heat Exchanger ◽  
Cross Section ◽  
Design Theory ◽  
Cooling System ◽  
Search Algorithm ◽  
Numerical Study ◽  
Heat Removal ◽  
Flow Distribution ◽  
Microchannel Cooling ◽  
Flow Maldistribution

A common assumption in basic heat exchanger design theory is that fluid is distributed uniformly at the inlet of the exchanger on each fluid side and throughout the core. However in reality, uniform flow distribution is never achieved in a heat exchanger and is referred to as flow maldistribution. Flow maldistribution is generally well understood for the macrochannel system. But it is still unclear whether the assumptions underlying the flow distribution in conventional macrochannel heat exchangers hold good for microchannel system. In this regard, extensive numerical simulations are carried out in a ‘U’ type parallel micro-channel system in order to study flow and heat transfer maldistribution and validated with in-house experimental data. A detailed parametric analysis is carried out to characterize flow maldistribution in a microchannel system and to study the effect of geometrical factors such as number of channels, n, Area of cross section of the channel Ac, manifold cross section area Ap, and flow parameter such as Reynolds number, Re, on the pressure and temperature distribution. In order to minimize the variation in pressure and to reduce temperature hot spots in the microchannel, a Response surface based surrogate approximation (RSA) and a gradient based search algorithm are used to arrive at the best configuration of microchannel cooling system. A three level factorial design involving three parameters namely Ac/Ap, Re, n are considered. The results from the optimization indicate that the case of n = 5, Ac/Ap = 0.12, and Re = 100 is the best possible configuration to alleviate flow maldistribution and hotspot formation in microchannel cooling system.

Cooling of Microelectronic Devices Packaged in a Single Chip Module Using Single Phase Refrigerant R-123

2009 ◽  
Author(s):  
Tushara Pasupuleti ◽  
Satish G. Kandlikar
Keyword(s):  
Single Phase ◽  
Cooling System ◽  
Electronic Devices ◽  
Working Fluid ◽  
Practical Application ◽  
Microelectronic Device ◽  
Single Chip ◽  
Microelectronic Devices ◽  
Cooling Devices ◽  
Microchannel Cooling

An approach towards practical application of microchannel cooling system is necessary as the demand of high power density devices is increasing. Colgan et. al. [1] have designed a unit known as Single Chip Module (SCM) by considering the practical issues for packaging a microchannel cooling system with a microelectronic device. The performance of the SCM has already been investigated by using water as working fluid by Colgan et. al. [1]. Considering the actual working conditions, water cannot be used in electronic devices as the working fluid because any leakage may lead to system damage. Alternative fluids like refrigerants were considered. In this research, the performance of SCM has been studied by using refrigerant R-123 as working fluid and compared with water cooled system. Cooling of 83.33 W/cm2 has been achieved for a powered area of 3 cm2 by maintaining chip temperature of 60°C. The heat transfer co-efficient obtained at a flowrate of 0.7 lpm was 34.87 kW/m2-K. The results obtained indicate that from a thermal viewpoint, R-123 can be considered as working fluid for microelectronic cooling devices.

A Honeycomb Microchannel Cooling System for Microelectronics Cooling

2011 ◽  
Vol 32 (7-8) ◽  
pp. 616-623 ◽  
Author(s):  
Xiaobing Luo ◽  
Yonglu Liu ◽  
Wei Liu
Keyword(s):  
Cooling System ◽  
Microchannel Cooling ◽  
Microelectronics Cooling
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