Drying plays a major role in which the free water molecules are removed leaving the essential bound water molecules. The ancient method used to preserve food is natural sun drying. But natural sun drying has many disadvantages such as uncontrolled drying, contamination by birds, insects and dust, climatic adversities etc. The quality of the product is found to be less and cannot be exported. It also requires more labour and the process is found to be slow. The main objective of the present work was to improve the quality of copra produced in a forced convection solar dryer. But it has been reported that the efficiency of evacuated tube collector is very high as compared to the efficiency of flat plate collectors.
However, the some experimental
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The hot air from the drying collector outlet is connected to the inlet of drying chamber. The blower is attached at the inlet of the drying collector for conducting the experiment of forced convection.
Fig. 1 Indirect type forced convection solar dryer
C. Experimental Procedure
Broken copra’s are uniformly spread in the trays and are kept inside the chamber for solar drying. In the designed solar dryer, air is blown into the evacuated tube collector with the help of the external device blower. The solar radiation falling on the collector, the collector gets heated up and transfers heat to the air flowing through the drying collector. This hot air enters the inlet of the drying chamber where copra is loaded in two trays. The moving hot air evaporates the water content (moisture) of the copra under the basic mechanism of removal of moisture from the surface of the product to the surrounding followed by the removal of moisture from inside the product to the surface [4]. The velocity of the air at the tray was adjusted by using a control valve. During the experiments, temperatures at various locations in the solar collector and the drier chamber, ambient dry and wet bulb
As a result of the design parameters from the experimental column, the following design is proposed: the column will run at a vapor velocity of 4.85 ft/hr and will have a HETP of 4.30 inches. This will result in a packing height of 38.7 feet. The reboiler will have an area of 113.52 ft2 and the area of the condenser will have a value of 45.54 ft2 in which heat exchange will take place.
The comparison between the vapour compression and vapour absorption systems are given in Table 1
...ut there is increase in water uptake ratio and cooking loss. Plasma treatment greatly affected the textural properties leading to reduction in hardness and stickiness of rice. With the results of water uptake kinetics it can be concluded that water uptake followed first order reaction. Basic information obtained from this study can be used to develop instant rice and other food products where cooking time is important factor particularly in designing of electric rice cookers. After application of plasma the results of contact angles and surface energies showed an increase in hydrophilic nature responsible for more water uptake. It can be concluded that the utilization of cold plasma, a novel technology in whole grain processing, not only maintained the high nutritional values of basmati rice, but also provided a better textural quality and reduction in cooking time.
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.
Tanning is a very controversial issue today. Tanning can take place directly under the rays of natural sunlight or in a tanning bed full of lights emitting fake rays on the same spectrum as the sun. Some say one is better than the other and vice versa. However, using a tanning bed to gain your summer bronze is a bad idea and there are quite a few reasons why.
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. .
With the ever growing increase in population, the demand for energy is increasing every day, and our dependence on non-renewable energy will one day come to an end. Energy is readily available everywhere and can be primarily classified into two principal groups, non-renewable and renewable. Non-renewable energy comes in numerous forms such as coal, oil, natural gas. However, these types of non-renewable energy resources are only available in limited supplies, and once they 're used up, they cannot be replaced. Renewable energy is an alternative to the traditional energy resources that we as a society currently use i.e. oil, coal, and natural gas. Non-renewable energy is also very expensive with regards to retrieving it from the earth and as we all know it causes substantial harm to our environment. Renewable energy or if you prefer green energy are resources that consist of solar, wind, water (hydro), biomass, and geothermal. Furthermore, renewable energy is energy that we do not have to fear about depleting because it is replenished naturally over moderately short periods of time.
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?”
... 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.
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...
Process bc : This high pressure and high temperature vapour then enters a condenser where the temperature of the vapour first drops to saturation temperature and subsequently the vapour refrigerant condenses to liquid state .
spoilage. To keep the food from spoiling, usually in only a few days, it is
Hot Water Heaters: The easiest way to exploit solar radiation is as thermal energy. One way to harness this solar energy is to heat water. Aro...
Freeze drying has been around and successful for a long time. The freeze drying method was first seen the ancient Indian tribes. The Peruvian Incas were the approximately the first to use this clever method. They did this by leaving their food out and allowing it to set in the cold weather and freeze. Then, the Incas stamped on their food to squash out any left over water. They then left their crushed food out in the sun in order to dry it. Freeze drying was later seen in World War II. This method was used in a slightly different way than the Incas, however. The military crews in WWII used ...