CHAPTER: 2
OVERVIEW OF SOLAR COLLECTOR
2.1 OVERVIEW OF SOLAR COLLECTOR : Solar collectors are special type of heat exchangers that transform solar radiation energy into thermal energy. The key component of all solar system is the solar collector. This is a device which absorbs the solar radiation from sun converts into heat and transfers this heat to a fluid ( air, water, oil ) passes through the collector. The solar energy collected is carried from the circulating fluid either directly to the hot water or to a thermal energy storage tank from which can be utilized for use at night or cloudy days. There are basically two types of solar collectors: non-concentrating/stationary and concentrating. A non-concentrating collector
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2.1. When solar radiation passes through a transparent cover and impinges on the blackened absorber surface of high absorptivity, a large portion of this energy is absorbed by the plate and then transferred to the transport medium in the fluid tubes to be carried away for storage or use. The underside of the absorber plate and the side of casing are well insulated to reduce conduction losses. The liquid tubes can be welded to the absorbing plate, or they can be an integral part of the plate. The liquid tubes are connected at both ends by large diameter header …show more content…
One or more sheets of glass or other diathermanous (radiation-transmitting) material. Tubes, fins, or passages. To conduct or direct the heat transfer fluid from the inlet to the outlet. Absorber plates. Flat, corrugated, or grooved plates, to which the tubes, fins, or passages are attached. The plate may be integral with the tubes. Headers or manifolds. To admit and discharge the fluid. Insulation. To minimise the heat loss from the back and sides of the collector. Container or casing. To surround the aforementioned components and keep them free from dust, moisture,
Solar energy is energy taken from the light that reaches earth's surface from the sun. There are four different kinds of solar energy, which are active solar systems, passive solar systems, photovoltaic cells and concentrating power systems. An active solar systems is a system that captures solar energy by mechanical means. Common active solar systems are often in buildings or homes. Some examples are roof collectors and water heating. Low Intensity and high variability have limited the use of active solar energy in Canada. A pass...
... heat. The tube-within-a-tube is constructed by placing one tube within a second tube. The shell and tube condenser uses cool water in the tubes and feeds the hot refrigerant in and condenses the refrigerant when it comes in contact with the tubes. Evaporative condenser uses open spray or spilled water to cool a condenser.
...enters in the pervaporation membrane unit in which a membrane is employed for separation. Only the refrigerant is passed through the membrane and collected on the other side. Vacuum is created at the downstream of the membrane. The refrigerant is condensed and throttled to the evaporator to produce cooling and then is absorbed in the absorber and the cycle repeats. The schematic diagram of this cycle is shown in Figure 8. The COP of the cycle utilizing pervaporation membrane process for vapour desorption is low as compared to conventional absorption systems as pervaporation process requires very high solution feed flow rate. The authors obtained a COP of 0.06 for their prototype working on the pervaporation membrane principle, they argued that the low COP is due to the high circulation ratio as high feed flow rate is required to operate such pilot membrane module.
The comparison between the vapour compression and vapour absorption systems are given in Table 1
good emitter of heat radiation so a lot of heat will be lost to the
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...
The sun has been a major aspect of life since the beginning of time. People used many other forms of energy before electricity was discovered. There has been a debate over energy resources for years. Many people are worried about what current energy resources may be doing to the environment. Oil spills and nuclear power plant mishaps have only been a few accidents that have had a big impact on the environment and the people who inhabit it. There are plenty of energy sources that do not harm the environment and are still able to get the job done. Solar energy is one energy alternative that will insure the betterment of the country and, at the same time, protect the natural environment.
Focusing sunlight to evacuated tube: A reflected surface with high specular reflectivity is utilized to focus light from the sun onto a small cooking region. Contingent upon the geometry of the surface, sunlight can be concentrated by a few requests of size creating temperatures sufficiently high to dissolve salt and noticed metal. For most household solar cooking applications, such high temperatures are not really required. Solar cooking items, along these lines, are ordinarily intended to accomplish temperatures of 150 °F (65 °C) (preparing temperatures) to 750 °F (400 °C) (flame broiling/singing temperatures) on a sunny day
Solar distillation uses the heat of the sun directly in a simple piece of equipment to
Nothing can make us happier throughout the year than having a sun-kissed tan. Solariums, also known as sun beds or tanning booths, are a popular way to achieve an amazing tan in a short time.[1] Solarium tanning involves lying in a horizontal booth for 3 to 5 minutes which surrounds you with ultraviolet light (as seen in picture). However, anti-solarium campaigners have caused a great debate as to whether solariums are a safe machine to use. Although, most forget that there is one important difference; when you are out in the sun, you cannot control the amount of UV light you are exposed to, because it is affected by changes in the atmosphere. Indoor tanning is one way to regulate the amount of UV light you are exposed to, because it is a controlled environment.
... temperature of 112 0C also and a pressure 2.5 bar. Cooling water is used to condense the vapor exiting column. Remaining methane and hydrogen are separated in reflux drum where the vapor stream is combined with other gases streams. The overhead of first and second separator are combined to form fuel gas. The liquid stream exiting in the bottoms of the reflux drum is pumped at pressure of 3.3 bar for discharging pressure. The pump stream is separated in two streams. One stream is to feed to tray one of the column and the other one stream is cooled down to 38 0C in heat exchanger. Then, the cooled product stream is sent to storage.
In 1910, Arthur Eddington, a British Astrophysicist, discovered solar winds. Solar winds are basically a continuous flow (they are never ending basically) of particles from the sun. They are also known as stellar winds. Their usual way out of the sun is the coronal holes. Their main cause is an expansion of gases in the corona, which is the outer layer of the sun. The idea that the corona is plasma was thought of by Richard C. Carrington. The temperature of the corona is 2,200,000 degrees Celsius. It is so hot that not even the sun’s gravity can contain it. It heats gases and makes them expand. The gas items run into each other as they are heated. As a result, they lose their electrons. Then, the atoms become ions with a positive charge, the electrons and ions (which are mostly Hydrogen ions) make up the solar wind. The velocity of solar winds goes from 250 to 1000 kilometers every second. It has a density of 82 ions for every cubic inch, or 5 ions per cubic centimeter. Solar winds are the cause of many occurrences in the solar system like Mercury having no atmosphere, and Venus’ acidic, radiation filled clouds. They are also known as electrically charged hurricanes.
In thermodynamics Refrigeration is the major application area, in which the heat is transferred from a lower temperature region to a higher temperature region. The devices which produce refrigeration are known as Refrigerators and the cycle on which it operates are called refrigeration cycles. Vapour compression refrigeration cycle is the most regularly used refrigeration cycle in which the refrigerant is alternately vaporized and condensed and in the vapor phase it is compressed. Gas refrigeration cycle is the well-known refrigeration cycle in which cycle refrigerant remains in the gaseous phase throughout the cycle. Cascade refrigeration are the other refrigeration cycles discussed in this chapter; absorption refrigeration is the one more refrigeration cycle which is used where the refrigerant is dissolved in liquid before it is compressed. One more refrigeration in which refrigeration is produced by passing the electric current through two dissimilar materials is called as the thermoelectric refrigeration.
First of all, solar energy is the energy produced when the sun heats the solar panel. Thus, when the sun heats the panels, it produces electricity. Solar power produces energy during the day and can store energy for the night. Solar power does not pollute the environment. However, it has high maintenance cost, and it takes a lot of land space.
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.