Many studies have been developed and carried out in terms of modeling of parabolic trough solar collector (PTSC) technology. In the following, 13 research papers related to the present work are studied, analyzed, and summarized.
Yaghoubi [15] evaluated the heat loss in the heat collector field of 250 KW solar power plant in Iran for several conditions. Experimental and numerical analysis have been made for comparison. Three different tubes are used; vacuum, lost vacuum and broken glass, and an infrared camera (IR) is used to evaluate the temperatures around the tube. The results showed that the heat loss of the lost vacuum (air) tube is 40% higher than the vacuum tube, so 3-5% of the efficiency of the collector is reduced. For the broken glass, the calculations showed that the thermal performance is reduced 12-16%.
Archer [16] developed a mathematical model of parabolic trough collector used for solar cooling and heating by using energy balance correlations between the absorber tube, glass tube, and surrounding. The proposed model is validated with experimental data at several operating cases which are HTF, direct normal solar radiation, wind velocity, and temperature. The results of comparison between the mathematical model and the experimental data indicate some differences including high measured glass temperature and low measured efficiencies. These differences are attributed to heat loss at the supports and the connectors and the low assumption of the absorptivity. Some recommendations have been suggested regarding the bellow connection and glass tube.
Gong [16] conducted a theoretical and experimental study to evaluate the heat loss of parabolic trough collector in China, Sanle3. Firstly, 1-D model is dev...
... middle of paper ...
...ate. In this model, the receiver is divided into several segments, and heat transfer balance equations which rely on the collector type, optical properties, heat transfer fluid (HTF), and ambient conditions are applied for each segment. That leads to predicate temperatures, heat loss, and heat gain of the parabolic trough. Results indicated that with the increase in temperature of absorber tube and heat transfer fluid (HTF), the heat loss of the parabolic trough collector increases and also heat gain decreases.
In this thesis, a 2-D model has been developed. The PTC is divided into several segments, and heat balance correlations are applied for each segment of the trough. This model estimates the thermal performance of the whole system as well as heat lost to the ambient. Validation of the model has been carried out also through preforming tests on the PTC.
Despite generating electricity with fossil fuels for years and years there is a much better way that does not harm the environment. Using Solar panels does not produce any carbon dioxide unlike fossil fuels that “produces huge volumes of carbon dioxide, which is a gas that influences the global climate” (“Solar Power Vs. Fossil Fuels”). Having the choice to get power in a new way that saves the environment, home owners should not have to think twice about trying solar. In fact if home owners collect some amount of watts per hour on Monday, that will not reduce the amount of solar energy a home owner can collect on Wednesday or any other day that week. They can always keep collecting the power. No matter what people may argue about how much coal, natural gas and petroleum remains buried in the Earth, those fossil fuels will run out far earlier than the life of the sun ("Solar Power Vs. Fossil Fuels"). Home owners should invest in solar energy because solar systems have very dependable technology with little maintenance, they offer financial savings and they are better for the environment.
With knowledge of a pool boiling curve, it is possible to predict the amount of heat transfer induced by the boiling of a fluid. The level of heat transfer that can be obtained for engineering applications is highly dependent on the difference in temperature between the heating surface and the surrounding fluid. The shape of this curve is dependent on the shape of heating surface as well as the material properties of the heated surface and fluid. Both empirical constants and dimensionless numbers are used to form a boiling curve. Optimal operation conditions for an application can be predicted with the understanding of how different factors can shape the boiling curve [1].
Step 2: The absorbance (A) is defined via the incident intensity Io and transmitted intensity I
The Solyndra Company, founded in 2005 by Christian Gronet, designed, manufactured, and sold a unique type of solar panels. They were termed “solar photovoltaic (PV) systems” and were designed for large, flat to low sloped commercial building roofs. The panels were designed to have the best performance when mounted horizontally and to be installed very close together so that they covered a much higher percentage of the roof top thus producing more electricity than the typical flat panel solar panels by comparison. This was created through the production by absorbing light from all directions including indirect and reflected light as well as direct sunlight when combined with a white roof. This was due to the design of having rolled its copper indium gallium selenite or CIGS into a cylindrical shape. Each tube had 40 of them in each 1-meter-by-2-meter panel (Solyndra, 2008).
Refrigeration, the production of cold, is an essential practice for present-day living. It is used in a many place like the processing and preservation of food, conditioning of air for comfort, manufacture of chemicals and other materials, cooling of concrete, medical applications etc. Refrigeration is defined as the science of maintaining the temperature of a particular space lower than its surrounding space. Refrigeration and air conditioning involves various processes such as compression, expansion, cooling, heating, humidification, de-humidification, air purification, air distribution etc. In all these processes, there is an exchange of mass, momentum and energy. All these exchanges are subject to certain fundamental laws. Hence to understand and analyses the refrigeration and air conditioning systems, a basic knowledge of the laws of thermodynamics, fluid mechanics and heat transfer is essential.
Three types of heat transfers help solar cookers use the sun’s energy to cook food. Heat is always transferred from the warmer object to the cooler object. Heat is also transferred to and through some materials better than others. The three types of heat transfers are radiation, conduction, and convection. Convection is the heat transfer by movement through materials such as air or a liquid. Materials like these are called mediums. Convection is the primary way heat can be transferred through liquids and gases. To classify a heat transfer as convection, hot air has to rise up to equally heat the air around it. Box solar cookers have to retain this hot air to cook food, so the cookers have to have lids with a transparent covering. The transparent covering shuts in all of the hot air and keeps out the cool air. The second heat transfer is the transfer of heat between two objects, or substances, that are directly in contact with each other. This heat transfer, called conduction is the primary way heat can be transferred through solids. In gases and liquids, conduction works poorly because the atoms have a great deal of space between them. Since they have a lot of space between each other, they can’t communicate heat to one another. The solid, aluminum foil, is commonly used in homemade solar ovens because it is a metal. It is well known metal is a great conductor of heat. Since metal (aluminum) is a great conductor of heat, whatever comes in contact with it will gradually absorb the heat from the metal. The third type of heat transfer is radiation. Radiation is the transfer of energy (heat) through space by electromagnetic waves. Solar energy reaches Earth by radiation (Pearson 485). When an energy wave comes directly in contact with...
This chapter explains the passive solar design techniques both in general context as well as in context of havelis. It also explains the key factors of passive solar design used in havelis of Rajasthan.
Heat transfer from high temperature heated surfaces finds considerable application in engineering. Because of its large number of applications in industries, considerable efforts have been made by researchers to investigate various aspects of the heat transfer and its fundamental principles involved. Fluid flow problems involving heat transfer viz. in presence of convention and radiation represents an idealization of many meaningful problems in engineering practice. Due to the presence of higher level of temperature required in many system like boiler, nuclear reactor; the effect of radiation heat transfer increases. So, there becomes a need of including radiative effect of the participating medium and also their boundary conditions. Keeping this in mind, an attempt was made to investigate the heat transfer in the Indian Pressurized Heavy Water Reactor (IPHWR) during Loss of Coolant Accident (LOCA) with low steam flow. This study will help in estimating the safe working limits for the heat dissipation in the reactor.
Cengel, Y. A., & Boles, M. A. (2011). Thermodynamics: An engineering approach (7th ed.). New York, NY: McGraw-Hill.¬¬¬¬
The sheffler concentrator is designed in such a way that all the rays that are parallel to the axis of parabolic shape of concentrator are converged towards the focus. So, if the concentrator is aligned in such a way that its axis points towards sun almost all the incoming radiations will be reflected towards the focus of the concentrator. Scheffler concentrators can provide high temperature of about 500 ֯ C for many applications such as kitchen cooking, sterilization and steam generation etc. The utilization of Scheffler concentrators has gained progressive popularity in many regions of the world (Scheffler,
Siegel, RP. "Solar Thermal: Pros and Cons - Part 1: Solar Heating and Cooling." Triple Pundit RSS. N.p., 21 May 2012. Web. 04 Mar. 2014. .
How Efficient is Solar Energy Technology? Engineering Challenges. n. d. a. d. a. d. d. 8 April 2014. http://www.engineeringchallenges.org/cms/8996/9082.aspx>. How do Nuclear Plants Work?”
Solar water heaters work by using energy from the sun. There are two types of systems for solar water heaters, an open system and a closed system (“Tapping into the Sun”). These systems depend on the type of climates they are installed in (“Tapping into the Sun”). Open systems are worth the installation if the weather is year round sunny, closed systems are better if the weather gets cold. The water cannot be run during winter so the system will be switched to fuel and in the summertime when it is warm, so the sy...
I am certain that all have heard of the terms green house gases, fossil fuels, and global warming. Have you ever questioned what will happen if nothing is done about the environmental problems facing the world today? What if I answer you that, we can merely use the power from the sun to power up our entire planet without the use of harmful energy sources, which affect our atmosphere? The power from the sun is what we call solar power. Solar power is the energy that comes from the sun as light and heat energy, and then it is later converted into electrical energy through solar panels (Nelson, 2008). This kind of power is completely free, right? Why should we put a lot of expense on other sources of energy, when there is a complete free and healthy power? It is evident that solar energy is a healthy source of energy, which will help stop global warming all together, but it is economically efficient to switch everything to solar energy. Solar energy is capable of becoming the world's future power supply because, it is renewable, eco-friendly, and extremely efficient when strategically placed.
Solar Cell Experiment Aim: To see how individual factors affect the output of a solar cell. Factors affecting the output of a solar cell: This experiment is going to be performed in the confines of a school laboratory, and so the complexity and cost of the experiment(s) should reflect this. However, to see how different factors affect the solar cell output, I will need to perform at least two experiments. The question is, which ones? · Distance from the light source will affect the solar cell output, because intensity of light on the solar cell will decrease, the further away from the light the cell is.