Development of a Computer Model for Solar Simulation and Shaded Fenestration Design

2001 ◽  
Author(s):  
John Kie-Whan Oh ◽  
Jeffrey S. Haberl ◽  
Larry O. Degelman
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Computer Model ◽  
Thermal Performance ◽  
Energy Efficient ◽  
Design System ◽  
The Sun ◽  
Physical Test ◽  
Shading Device ◽  
Solar Simulation

Abstract The goal of this study was to develop a computer model for solar radiation calculation and display and a shaded fenestration design system that can be used by architectural and engineering designers. This computerized model calculates the amount of insolation and transmitted solar radiation through a shaded window as well as the heat transfer through it. The computer model, called Shaded Fenestration Design (SFD), contains various functions relating to solar simulation such as: display of the sunpath diagrams and the accompanying shading mask protractor, display of the hourly intensity of solar radiation onto the path of the sun for horizontal and vertical surfaces at varying off-south azimuths, and simulating the thermal performance of a shaded fenestration. The model also provides graphical aids for energy-efficient shading device design with use of various kinds of sunpath diagrams and solar radiation diagrams. The model performs solar radiation simulation using the methods developed in the ASHRAE Handbook, Duffie and Beckman, and Kreider and Rabl. An anisotrophic sky model was applied for the calculation of solar radiation on a titled surface and the transmitted solar radiation through a single-glazed window. A part of the model was validated experimentally using a physical test box and was also compared to simulated results from the DOE-2 program; however, the validation is not included in this paper.

scholarly journals AN EXPERIMENTAL VERIFICATION OF INFLUENCING FACTORS ON THE MECHANISM OF HEAT TRANSFER IN THE CAVITY ROOF VENTILATION

2015 ◽  
Vol 5 (2) ◽  
Author(s):  
DRAGANA TEMELJKOVSKI
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Solar Radiation ◽  
Thermal Performance ◽  
Experimental Verification ◽  
Thermal Damage ◽  
Building Envelope ◽  
Cooling Effect ◽  
The Sun ◽  
Key Words Temperature

The roof, as a part of the building envelope with the thermal performance that’s a major requirement for guaranteeing a comfortable and hygienic interior climate, provides protection from thermal damage incurred by the sun. To improve this protection ability, the use of a ventilated roof can be considered, which has a ventilation layer known as a cavity, beneath the roof cover panel. Based on the proposed mechanism of heat transfer and the influence of such factors as cavity ventilation, the slope of the roof, intensity of solar radiation, the size and shape of the cavity, and panel profiles, airflow and temperature distribution are analyzed in the cavity, in an effort to improve the cooling effect of ventilation in the cavity of the roof. In this study, the influence of these elements on airflow is studied. Key words: temperature distribution, cooling effect, air flow, thermal comfort, ventilation channel.

Assessment of the Thermal Performance of Alternate Firing Schemes in Oxygen-Fired Glass Melting Furnaces

2003 ◽  
Author(s):  
Kris L. Jorgensen ◽  
Satish Ramadhyani ◽  
Raymond Viskanta
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Computer Model ◽  
Thermal Performance ◽  
Glass Melting ◽  
Side Wall ◽  
Shear Stresses ◽  
Heat Transfer Characteristics ◽  
Unstable Flow ◽  
Transfer Characteristics

Three firing schemes for an industrial oxygen-fired glass melting furnace were examined to determine the thermal performance and relative merits of each scheme. A comprehensive computer model was used to investigate the effects of each scheme on the combustion and heat transfer in the furnace. The three-dimensional computer model, suitable for predicting and analyzing fluid flow, combustion and heat transfer has been used to simulate the combustion space of the furnace. The turbulent flow field is obtained by solving the Favre averaged Navier-Stokes equations and using the k-ε model to calculate the turbulent shear stresses and close the equation set. The combustion model consists of a single step, irreversible, infinitely fast reaction. A mixture fraction is used to track the mixing of fuel and oxidant and thus reaction progress in this mixing limited model. An assumed shape PDF method is utilized to account for turbulent fluctuations. Radiative heat transfer in the combustion gases and between surfaces is modeled using the discrete ordinates method coupled with the weighted-sum-of-gray-gases model. The model furnace for all three firing schemes was the same size and shape, was charged from the rear end wall and was pulled from the front wall. The three schemes investigated were: 1) non-interlaced side-wall fired, 2) interlaced side-wall fired, and 3) end fired. The results show that all three arrangements provide similar thermal performance and heat transfer characteristics. However, the flow field for the non-interlaced arrangement is very complex in the region where jets from opposing walls meet at the furnace center line. This type of jet interference can lead to unstable flow, particularly at the centerline of the furnace. Unstable flow conditions can affect the heat transfer characteristics of the furnace and make the furnace difficult to operate. Conversely, the interlaced and end-fired schemes do not exhibit the jet interference seen in the non-interlaced arrangement. While the results indicate that the thermal performance of all three arrangements were similar, the possibility of jet interference suggests that an interlaced or end-fired arrangement is preferable.

scholarly journals Heat Conduction On Pan Using Portable Parabolic Stove With Addition Of Flat Mirror

2020 ◽  
Vol 6 ◽  
Author(s):  
Benedictus Mardwianta ◽  
Abdul Haris Subarjo ◽  
Wayan Wiardefan
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Solar Radiation ◽  
Surface Temperature ◽  
Experimental Method ◽  
Wall Temperature ◽  
Open Space ◽  
The Sun ◽  
Parabolic Mirror ◽  
Flat Mirror

This research aims to develop the parabolic stove with addition of some flat mirrors around the parabolic mirror. It will increase the heat transfer of conduction in the pan. The parabolic itself has around and concave shape, making it suitable for concentrating solar energy. The experimental method was carried out in this research and the test was carried out in an open space with solar radiation intensities with ranging from 169.6 W/m² to 974.4 W/m². The results of heat conduction on a pan without the addition of a flat mirror generate a 105.15 Watt, addition of one flat mirror will generate a 174.82 Watt, addition of two  flat mirrors will generate a 259.24 Watt, addition of three flat mirrors will generate a 342.79 Watt and addition of four flat mirrors will generate a 412.26 Watt. The heat conduction depends on the intensity of the sun caught by the reflector. If the sun intensity decreases, the surface temperature between of the outer pan wall (T1) and the inner wall temperature (T2) will decrease too. Keywords: Heat conduction, sun intensity, parabolic stove

Experiment of a Flat Plate Solar Water Heater Collector with Modified Design and Thermal Performance Analysis

2014 ◽  
Vol 624 ◽  
pp. 332-338 ◽  
Author(s):  
Shouquat Hossain ◽  
Ali Wadi Abbas ◽  
Jeyraj Selvaraj ◽  
Ferdous Ahmed ◽  
Nasrudin Bin Abd Rahim
Keyword(s):  
Heat Transfer ◽  
Solar Radiation ◽  
Flat Plate ◽  
Thermal Performance ◽  
Solar Water Heater ◽  
Water Heater ◽  
Pipe Surface ◽  
Solar Water ◽  
Useful Heat ◽  
Absorber Surface

An investigation is reported of the thermal performance of a flat plate solar water heater with a circulating absorber pipe surface. The thermal performance of the 2-side parallel serpentine flow solar water heater depends significantly on the heat transfer rate between the absorber surface and the water, and on the amount of solar radiation incident on the absorber surface. The modified pipe arrangement has a higher characteristic length for convective heat transfer from the absorber to the water, in addition to having more surface area exposed to solar radiation. It means during the operation of water heater, more solar energy is converted into useful heat. However, this modification has reduced the efficiency of the system marginally.

Performance Study of a Bi-Directional Thermodiode Designed for Energy-Efficient Buildings

2002 ◽  
Vol 124 (3) ◽  
pp. 291-299 ◽  
Author(s):  
Wongee Chun ◽  
Kuan Chen ◽  
Hyung Taek Kim
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Energy Efficient ◽  
Onset Time ◽  
Incident Radiation ◽  
Maximum Temperature ◽  
Performance Study ◽  
Energy Efficient Buildings ◽  
Diode System ◽  
Shading Device

A new, bi-directional thermodiode designed for energy-efficient buildings was constructed and tested. Experimental results are presented and discussed for solar-heating applications. The thermodiode system consisted of a number of rectangular loops filled with water. The tilting angle of the loops can be altered to reverse the direction of natural convection within the loops for bi-directional operations. The horizontal segments of the loops were attached to metallic panels facing indoors or outdoors. The amount of thermal radiation incident on the outdoor-facing surfaces can be adjusted by rotating the panels or by installing a removable shading device in front of the surfaces. Results of the indoor tests for winter use of the diode showed an onset time between 7 to 20 min for natural convection to be induced throughout the loops in the thermodiode. Before the throughflow started, the fluid in the heated copper tubes reached its maximum temperature. A sudden drop and rebound in this temperature was observed immediately after the onset of throughflow. After that, temperatures at different locations on the thermodiode rose at approximately the same rate until a steady state was reached. During the cool-down phase, the temperatures decreased at the same rate without humps, indicating only conduction took place in the rectangular loops when the thermodiode was reverse-biased. A simple analytical model was developed to estimate the temperature variations and heat transfer rates in the diode system. The diode under forward-biased condition increases the heat transfer rate by nearly 100 times for an incident radiation of 600 W/m2.

scholarly journals Evaluation of Building Energy Performance with Optimal Control of Movable Shading Device Integrated with PV System

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1799
Author(s):  
Dong Eun Jung ◽  
Chanuk Lee ◽  
Kwang Ho Lee ◽  
Minjae Shin ◽  
Sung Lok Do
Keyword(s):  
Heat Transfer ◽  
Optimal Control ◽  
Solar Radiation ◽  
Radiation Effects ◽  
Radiation Energy ◽  
Energy Performance ◽  
Control Logic ◽  
Pv System ◽  
Cooling Period ◽  
Shading Device

Among the envelope components (e.g., walls, roofs, floors, and windows, etc.) affecting the cooling and heating load of buildings, windows are the most thermally vulnerable. Shading devices can minimize the thermal load on windows due to solar radiation and decrease radiation effects. However, the load changes due to convection and conduction should be considered. Therefore, when a shading device is applied to a window, control logic for thermal blocking and heat retention is necessary to prevent the load changes. In addition, by combining the opposite features of photovoltaic (PV) that require solar radiation and the shading device to block solar radiation, energy-saving and production can be achieved simultaneously. Therefore, this study minimized the thermal effects of windows using a movable shading device integrated with PV and evaluated the PV power generation. This study evaluated the effects on window heat transfer by applying artificial intelligence techniques, which have recently attracted attention, to system operation. To achieve this, artificial neural network (ANN)-based control logic was developed, and the control performance of the system was assessed using simulations. In ANN control, the window heat transfer was 86.3% lower in a cooling period and 9.7% lower in a heating period compared with that of a shading device fixed at 45°. Furthermore, the PV system produced 3.0 to 3.1% more electric power under optimal control during the cooling period.

scholarly journals Assessment of the energy efficiency of a window system with a shading device of the egg-crate type

Vestnik MGSU ◽  
2021 ◽  
pp. 655-665
Author(s):  
Chan Ngoc Tran ◽  
Nguyen Thi Khanh Phuong ◽  
Ekaterina V. Gorbarenko
Keyword(s):  
Energy Efficiency ◽  
Solar Radiation ◽  
High Energy ◽  
Regression Equations ◽  
The Sun ◽  
Heat Gain ◽  
Window System ◽  
Gain Reduction ◽  
Shading Devices ◽  
Shading Device

Introduction. The article proposes a new energy efficiency assessment method based on a new technique used to calculate the window heat gain. The proposed method takes account of the coefficient of irradiance reduction by the sun shading device. The study was carried out for the shading device of the egg-crate type. Materials and methods. Calculations are based on the projection of a sunbeam performed for a fraction of a window area in the shade. They take account of the coefficient of irradiance reduction applied due to the presence of the sun shading device. A shading device reduces the irradiance, caused by diffused solar radiation, and coefficient Kbt is applied to demonstrate this process. This coefficient was identified in an experiment and expressed in the form of regression equations. To evaluate the energy efficiency with regard for the effectiveness of shading devices, coefficient of solar radiation gain reduction β was developed. This coefficient is described by the ratio of the value of solar radiation incoming through a glazed window in the presence of shading device QK to the value of solar radiation incoming through a glazed window that has no shading QKo. The software programme was used to verify the calculations of the heat gain from the solar radiation incoming through the window system with regard for the shading device in various geographical regions in summer (in Hanoi and Moscow). Results. The results, obtained using the proposed methodology and the observation data, show an insignificant difference in the relative value of β; and they demonstrate a major error when qwindow, or the absolute value of heat entering the room, is taken account of. The heat load, incoming through the window system, is down by 42–45 % in Moscow and by 45–53 % in Hanoi in the hottest period of the year if shading devices are used. Conclusions. The proposed methodology and computer software, used for a quick assessment of the energy efficiency of a window system equipped with shading devices, allow to design building envelopes that feature high energy efficiency in terms of air conditioning systems, given that coefficient of radiation gain reduction β is taken account of.

scholarly journals A thermo-bio-architectural framework (ThBA) for finding inspiration in nature: Biomimetic energy efficient building design

2021 ◽  
Author(s):  
◽  
Marzieh Imani
Keyword(s):  
Heat Transfer ◽  
Case Studies ◽  
Thermal Performance ◽  
Energy Efficient ◽  
Energy Use ◽  
Thermal Adaptation ◽  
Building Design ◽  
Energy Performance ◽  
Efficient Design ◽  
Wide Range

<p>Design inspired by nature has been known as biomimicry or biomimetic design that is believed to transform human technologies into a sustainable status through translation of biological models, systems, and processes. Considering energy efficiency as one of the aspects of sustainability in the concept of bio-inspired building design, the problem was how to access the solutions best matched to the design problem. Various tools for finding existing knowledge from a different domain are described but as yet there appears to be no tool for allowing building designers to access the efficient ways found in nature of producing energy, using energy, and recycling resources. What the research investigated was to find if it is possible to develop a generalised thermo-bio-architectural (ThBA) framework by use of which architects would be able to improve the energy performance of buildings in a wide range of climates, by following a systematic process that methodically connects design thermal challenges to thermal adaptation principles used in nature.  The ThBA was developed by studying biology to find how thermal regulation strategies used by living organisms can be classified and generalised. The proposed ThBA was confirmed and evaluated before it was used for the rest of the research. The biological part of the ThBA was assessed by biological experts within a focus group session. Having the ThBA confirmed, the research also investigated how the heat transfer principles in buildings can be articulated to be linked to the generalised thermal adaptation strategies in nature. For this, a series of case studies were selected and for each an energy simulation was run to analyse its thermal performance and identify its thermal challenges.  Then, the ThBA was used to introduce innovative solutions for improving the thermal performance of the case studies with big energy use to reveal unexpected techniques or technologies. This, however, necessitated its reconfiguration so as to be useful for architects.  Testing the ThBA for two extreme climates in New Zealand, highlighted the fact that the simple translation of the majority of biological thermal adaptation principles are being used by architects, although for some, the architectural equivalents did not function in exactly in the same way as biological thermoregulation strategies. The differences were seen either in the central thermoregulatory principles or the broader properties within which the key principles fitted. Apart from that, for both architectural and biological thermoregulatory strategies the heat transfer parameter and methods were the same. Given that, in a context where biomimicry is understood as the imitation of complicated thermoregulatory solutions in nature for which innovation is evolutionary achieved, the term biomimetics seems to not have a place in the context of bio-inspired energy efficient design considering the current state of technology. The ThBA, however, suggested a few strategies that might address opportunities for designing a new generation of buildings in the future. This implies that the ThBA is more useful for researchers than architects.</p>

scholarly journals A thermo-bio-architectural framework (ThBA) for finding inspiration in nature: Biomimetic energy efficient building design

2021 ◽  
Author(s):  
◽  
Marzieh Imani
Keyword(s):  
Heat Transfer ◽  
Case Studies ◽  
Thermal Performance ◽  
Energy Efficient ◽  
Energy Use ◽  
Thermal Adaptation ◽  
Building Design ◽  
Energy Performance ◽  
Efficient Design ◽  
Wide Range

<p>Design inspired by nature has been known as biomimicry or biomimetic design that is believed to transform human technologies into a sustainable status through translation of biological models, systems, and processes. Considering energy efficiency as one of the aspects of sustainability in the concept of bio-inspired building design, the problem was how to access the solutions best matched to the design problem. Various tools for finding existing knowledge from a different domain are described but as yet there appears to be no tool for allowing building designers to access the efficient ways found in nature of producing energy, using energy, and recycling resources. What the research investigated was to find if it is possible to develop a generalised thermo-bio-architectural (ThBA) framework by use of which architects would be able to improve the energy performance of buildings in a wide range of climates, by following a systematic process that methodically connects design thermal challenges to thermal adaptation principles used in nature.  The ThBA was developed by studying biology to find how thermal regulation strategies used by living organisms can be classified and generalised. The proposed ThBA was confirmed and evaluated before it was used for the rest of the research. The biological part of the ThBA was assessed by biological experts within a focus group session. Having the ThBA confirmed, the research also investigated how the heat transfer principles in buildings can be articulated to be linked to the generalised thermal adaptation strategies in nature. For this, a series of case studies were selected and for each an energy simulation was run to analyse its thermal performance and identify its thermal challenges.  Then, the ThBA was used to introduce innovative solutions for improving the thermal performance of the case studies with big energy use to reveal unexpected techniques or technologies. This, however, necessitated its reconfiguration so as to be useful for architects.  Testing the ThBA for two extreme climates in New Zealand, highlighted the fact that the simple translation of the majority of biological thermal adaptation principles are being used by architects, although for some, the architectural equivalents did not function in exactly in the same way as biological thermoregulation strategies. The differences were seen either in the central thermoregulatory principles or the broader properties within which the key principles fitted. Apart from that, for both architectural and biological thermoregulatory strategies the heat transfer parameter and methods were the same. Given that, in a context where biomimicry is understood as the imitation of complicated thermoregulatory solutions in nature for which innovation is evolutionary achieved, the term biomimetics seems to not have a place in the context of bio-inspired energy efficient design considering the current state of technology. The ThBA, however, suggested a few strategies that might address opportunities for designing a new generation of buildings in the future. This implies that the ThBA is more useful for researchers than architects.</p>

scholarly journals Thermal Performance on Parabolic Solar trough Collector by using Rgo/Water Nanofluid

2020 ◽  
Vol 8 (6) ◽  
pp. 1406-1411
Keyword(s):  
Solar Radiation ◽  
Flow Rate ◽  
Thermal Performance ◽  
Mass Fraction ◽  
Pure Water ◽  
The Sun ◽  
Parabolic Trough ◽  
Heating Systems ◽  
Solar Water Heating ◽  
Solar Water

The solar water heating systems are one of the popular devices to harness the sun radiation incident on the surface of earth at free of cost. The ASHARE standards 93-86 were followed to study the thermal performance of parabolic solar trough collector using rGO/water nanofluid with the mass fraction of 1% used as a working coolant. To enhance the efficiency regarding temperatures variations, flow rate, and incident solar radiations was examined. These results show that influencing of nanofluid on the collector had more efficient than with pure water owing to solar radiation and flow rate. The efficiency of solar parabolic trough collector has improved with an effect of nanofluid compared to pure water.

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