Modeling and simulation of a simple glass window
TL;DR: In this paper, a mathematical model with numerical simulations of the heat transfer across a simple glass window is presented, which is two-dimensional, transient based upon the energy equation with a source term to account for the solar radiation absorbed through the glass sheet.
Abstract: This paper presents a mathematical model with numerical simulations of the heat transfer across a simple glass window. The model is two-dimensional, transient based upon the energy equation with a source term to account for the solar radiation absorbed through the glass sheet. Variable incident solar radiation and external ambient temperature are considered in the numerical simulations. The governing equations and the associated boundary conditions are discretized by the finite difference approach and the ADI scheme. Numerical simulations are realized for the cases of clear and absorbing glass to show the effect of the glass thickness on the total heat gain, the solar heat gain and the shading coefficient.
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TL;DR: In this paper, the authors presented a one-dimensional transient heat transfer model, the Semi-Transparent Photovoltaic module Heat Gain (SPVHG) model, for evaluating the heat gain of semi-transparent PV modules for building-integrated applications.
Abstract: This paper presents a one-dimensional transient heat transfer model, the Semi-transparent Photovoltaic module Heat Gain (SPVHG) model, for evaluating the heat gain of semi-transparent photovoltaic modules for building-integrated applications. The energy that is transmitted, absorbed and reflected in each element of the building-integrated photovoltaic (BIPV) modules such as solar cells and glass layers were considered in detail in the SPVHG model. Solar radiation model for inclined surface has been incorporated into the SPVHG model. The model is applicable to photovoltaic (PV) modules that have different orientations and inclinations. The annual total heat gain was evaluated by using the SPVHG model. The impacts of different parameters of the PV module were investigated. It was found that solar heat gain is the major component of the total heat gain. The area of solar cell in the PV module has significant effect on the total heat gain. However, the solar cell energy efficiency and the PV module's thickness have only a little influence on the total heat gain. The model was also validated by laboratory tests by using a calorimeter box apparatus and an adjustable solar simulator. The test results showed that the simulation model predicts the actual situation well.
202 citations
TL;DR: This survey, although extensive cannot include every paper; some selection is necessary, is intended to encompass the English language heat transfer papers published in 2003, including some translations of foreign language papers.
Abstract: The present paper is intended to encompass the English language heat transfer papers published in 2003, including some translations of foreign language papers. This survey, although extensive cannot include every paper; some selection is necessary. Many papers reviewed herein relate to the science of heat transfer, including numerical, analytical and experimental works. Others relate to applications where heat transfer plays a major role not only in man-made devices, but in natural systems as well. The papers are grouped into categories and then into sub-fields within these categories. We restrict ourselves to papers published in reviewed archival journals. Besides reviewing the journal articles in the body of this paper, we also mention important conferences and meetings on heat transfer and related fields, major awards presented in 2003, and books on heat transfer published during the year.
106 citations
Cites background from "Modeling and simulation of a simple..."
...Heat transfer across a glass sheet is modeled to show the impact of glass thickness on total heat gain, and shading coefficient [1619]....
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TL;DR: In this article, the authors investigated the balance between the energy needs for heating and cooling the space that the shading device is used for and the energy that was used for lighting the same space and the amount of energy that a fixed shading device can produce.
Abstract: The use of external fixed shading devices to adjust solar influx radiation and to save energy is well known. However, fixed shading devices can reduce daylight availability, increase artificial light needs and block the beneficial winter solar radiation. This paper is part of a research on the characteristics of the optimum shading device. The aim is to investigate the balance between the energy needs for heating and cooling the space that the shading device is used for and the energy that is used for lighting the same space and the energy that the shading device can produce. In order to investigate the balance between the above mentioned parameters, thirteen types of fixed shading devices have been studied and categorized according to their energy performance, for a single occupant office room. The same office room is tested for two different Mediterranean latitudes in Athens and in Chania, Crete in Greece and for two different south facing windows’ sizes. The thermal behavior of the devices is assessed through computer simulation application and the daylight analysis is assessed with both computer simulation and physical modeling. Stable parameters were the internal loads in the office room, the south orientation of the facade and the type of glazing. Variable parameter was the type of the fixed shading device. The study shows that all shading devices with integrated south facing PV can efficiently produce electricity which may be used for lighting. The study highlights the fact that shading devices such as Surrounding shading, Brise–Soleil full facade and Canopy inclined double work efficiently against thermal and cooling loads and may be used to produce sufficient electricity and control daylight. The study defines the geometrical parameters that will be incorporated to the overall characteristics of the optimum fixed shading device and proposes new fields of development for the BIPV technologies.
105 citations
TL;DR: In this paper, the authors investigated the thermal performance of glazed solar chimney walls (GSCW) under the tropical climatic conditions of Thailand and reported that the induced airflow rate was about 0.13-0.28m 3 /s.
Abstract: This paper reports investigation on the thermal performance of glazed solar chimney walls (GSCW) under the tropical climatic conditions of Thailand. The GSCW consisted of double glass panes with an air layer and openings located at the bottom (room side glass pane) and at the top (ambient side glass pane). A prototype of GSCW was integrated into the southern wall of a small room of 2.8 m 3 volume. Its dimensions were as follows: 0.74 m height, 0.50 m width and 0.10 m air gap. The size of openings was 0.05 × 0.5 m 2 . With a clear glass of 6 mm thickness, velocity field measurement indicated that the induced airflow rate was about 0.13–0.28 m 3 /s. The temperature difference between room and ambient was less than that with a single layer clear glass window. The reduction of daylight due to the double glass layer is negligible. Comparison between simulated and experimental results showed a reasonable agreement, therefore, the developed numerical model is valid and could be used as a tool for the design of GSCW.
72 citations
TL;DR: In this paper, a PV-Trombe wall (PV-TW) is installed in a fenestrated room with heat storage to approach the practical application of PV-TW.
Abstract: In this paper, a PV-Trombe wall (PV-TW) installed in a fenestrated room with heat storage is investigated to approach the practical application of PV-TW. Based on an updated mathematical model, theoretical simulation has been conducted for PV-TW in this case. Furthermore, field testing for this case has also been performed to validate the model, and then the simulated and experimental results are compared and found in considerably good agreement. The testing results show that a significant indoor temperature increase can be obtained in a fenestrated room with PV-TW and heat storage. Meanwhile, the experimental daily average electrical efficiency of this PV-TW can reach 10.4%.
68 citations
Cites methods from "Modeling and simulation of a simple..."
...When a window is introduced, the modeling and simulation of a simple glass window was implemented [10], and the influence of window on the effective solar absorptance was estimated by calculating the redistribution of solar energy in rooms [11]....
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References
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Book•
01 Jan 1970
TL;DR: A review of thermodynamic properties of Moist Air can be found in this paper, where the authors also present a detailed discussion of the direct contact transfer process between Moist air and water.
Abstract: I INTRODUCTION 1 Introduction to Heating, Ventilating, Air Conditioning, and Refrigeration 2 Review of Thermodynamics, Fluid Mechanics, and Heat Transfer II REFRIGERATION 3 Mechanical Vapor-Compression Refrigeration Cycles 4 Mechanical Vapor-Compression Refrigeration Components and Systems 5 Absorption Refrigeration 6 Ultralow-Temperature Refrigeration: Cryogenics III PSYCHROMETRICS 7 Thermodynamic Properties of Moist Air 8 Psychometric Processes and Applications 9 The Psychrometer and Humidity Measurement IV HEAT- AND MASS-TRANSFER PROCESSES AND APPLICATIONS 10 Direct-Contact Transfer Processes Between Moist Air and Water 11 Heating and Cooling of Moist Air by Extended Surface Coils 12 Human Thermal Comfort and Indoor Air Quality 13 Solar Radiation V HEATING- AND COOLING-LOAD CALCULATIONS IN BUILDINGS 14 Winter Design Heat Loss 15 Instantaneous Heat Gain 16 Instantaneous Cooling Load 17 Energy-Estimation Methods VI AIR AND WATER DISTRIBUTION SYSTEM DESIGN 18 Air-Distribution System and Duct Design 19 Hydronic System Operation and Design Appendix A Thermodynamic and Thermophysical Property Tables Appendix B Weather Data Appendix C Refrigerant, Cryogenic, and Psychrometric Charts Index
796 citations
TL;DR: In this article, the authors present a review of heat-mirror deposition technology including chemical vapor deposition using hydrolysis and pyrolysis reactions, dc and rf sputtering using reactive, biased and nonreactive techniques, vapor deposition and ion plating.
Abstract: Heat-mirror coatings are important as transparent insulation for a host of applications, including building window glazings. They reduce thermal emittance of glass and polymeric substrates, thereby decreasing the effective radiative loss of a glazing or window assembly. Properties of coatings and substrates, as well as various window designs, are detailed. The paper reviews heat-mirror deposition technology including chemical vapor deposition using hydrolysis and pyrolysis reactions, dc and rf sputtering using reactive, biased and nonreactive techniques, vapor deposition and ion plating. The properties of single-layer films including coatings of In 2 O 3 :Sn, doped SnO 2 , Cd 2 SnO 4 , noble and transition metal films are enumerated. Multilayer films described include dielectric overcoated metals such as ZnS/metal/ZnS, Bi 2 O 3 /Au/Bi 2 O 3 and TiO 2 /Ag/TiO 2 . Electrical, solar and infrared radiative properties are tabulated. Much of the data presented is also useful for photovoltaic and collector applications. New and innovative materials systems are suggested.
291 citations
TL;DR: In this paper, the authors present a review of the state-of-the-art of the science and technology of vacuum glazing, and their method of manufacturing in the laboratory.
Abstract: This paper reviews the current state-of-the-art of the science and technology of vacuum glazing. The construction of vacuum glazing, and its method of manufacture in the laboratory, is described. Experimental data are presented on the magnitude of heat flows through vacuum glazing. Gaseous heat transfer is negligible, and the internal vacuum is shown to be stable over many years, in well-manufactured glazing. Values of air-to-air, centre-of-glazing thermal conductance have been achieved ranging from 3 W m −2 K −1 (for vacuum glazing with no internal low emittance coating) to 0.8 W m −2 K −1 (for samples with two internal low emittance coatings). The overall heat transport rate through 1 m×1 m samples of vacuum glazing has been measured in accurately calibrated guarded hot box instruments. The results obtained agree to within experimental error (±6%) with those estimated on the basis of local measurements of heat transfer due to radiation, pillar conduction and lateral heat flow through the edge seal. Sources of mechanical tensile stress in vacuum glazing are identified. Stresses due to atmospheric pressure occur in the vicinity of the pillars, and (in poorly designed glazing) near the edge seal. Stresses due to temperature differences are influenced by many factors including the external heat transfer coefficients, level of insulation of the glazing, edge insulation, and edge constraints. Methods of estimating these stresses are discussed. It is shown that vacuum glazing can be designed with adequately low stresses, and low thermal conductance.
185 citations
TL;DR: In this article, the results of a numerical and experimental study on thermally efficient windows were presented, which indicated large reduction in the infrared and ultraviolet radiations while maintaining good visibility.
Abstract: This paper presents the results of a numerical and experimental study on thermally efficient windows. Experimental investigation using spectrophotometry was realized on simple and composite glass samples filled with air or phase change material. The transmittance and reflectance tests indicated large reduction in the infrared and ultraviolet radiations while maintaining good visibility. The number of glass sheets, their thickness and the gap between them were also investigated. The numerical model is based upon one-dimensional formulation of the composite window. The program was optimized and the predicted results are presented and discussed.
128 citations
TL;DR: In this article, an external wall system for solar space heating and daylighting composed of transparent insulation material (TIM) and translucent phase change material (PCM) is presented.
Abstract: An external wall system for solar space heating and daylighting composed of transparent insulation material (TIM) and translucent phase change material (PCM) is presented. This system enables selective optical transmittance of solar radiation. Visible light is mainly transmitted and invisible radiation is mainly absorbed and converted to heat, causing in particular phase change. The storage medium is also the absorber. The concept of the system is presented in detail together with the investigations carried out, including a brief outline of modeling, optical experiments on PCM samples and long-term experiments on a prototype wall as well as numerical simulations. The results indicate a promising thermal–optical behavior of the system. For instance in a Swiss lowland climate (Zurich-airport) a mean energy flux of 13 W m −2 (system efficiency 0.27) was calculated through a south facing TIM–PCM wall into the building during the month with the lowest irradiation (December). The parameters of the prototype wall with a mean melting temperature of the PCM of 26.5°C were assumed. When considering the percentage of time in which the building does not lose energy through the south facing TIM–PCM wall, a maximum can be reached with a mean melting temperature of approximately 20 to 21°C. In this case energy losses through the facade occur only during 1% of the time. With regard to the practical application of the system in buildings, aspects of reliability and durability have to be further investigated.
104 citations