THERMOELECTRIC COOLING
In thermoelectric cooling Peltier’s effect is used to cause heat flux between the junctions of different types of materials. A Peltier heater/cooler transfers heat from one side of the device to the other by consuming electrical energy. This device is also known as a Peltier device, Peltier heat pump, solid state refrigerator, or thermoelectric cooler (TEC). Since there are more economical and easy ways of achieving cooling, Peltier’s devices are mostly used for cooling purposes. However, since a single device can be used for both heating and cooling, the desirability of Peltier’s device is more. By connecting a thermoelectric refrigerator to a DC voltage, one side of the peltier device cools while the other stays warm. The effectiveness of cooling depends on the amount of current and how well the heat is removed by the pump from the hot side. Peltier coolers and thermoelectric generators are exact opposites of each other. Peltier cooler uses power to generate temperature difference, whereas, thermoelectric generator uses temperature difference to generate power. Both the above mentioned devices have operations closely related to one another (both are thermoelectric effect applications), and therefore their constructions, raw materials used and designs are somewhat similar.
Figure 6: Peltier element schematic: Thermoelectric legs are thermally in parallel and electrically in series.
Figure 7: Peltier element (16x16 mm)
As compared to an ideal refrigerator(Carnot cycle), the thermoelectric junctions are 5-10% efficient, whereas, the conventional compression cycle systems(compression/ expansion used by reverse Rankine systems) have 40-60% efficiency. Therefore, thermoelectric cooling, due to it’s a ...
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...iency is governed by the figure of merit, ZT. Even though there is no above limit for ZT, no thermoelectric material has a value greater than 1. 2010 devices focus more on reliability and portability than efficiency.
Internal combustion engines capture 20-25% of the released energy during fuel combustion. Increase in the rate of conversion increases mileage and more electricity can be used for on-board controls and comfort and safety features such as navigation systems, stability control, telematics, electronic breaks etc. Shifting the energy withdrawn from the engine to the electrical load in the car is also possible eg. Electrical coolant pump operation.
The heat produced during generation of electricity can be used for alternative uses by cogeneration power plants. Such systems along with solar thermal energy generation can be applications of thermoelectrics.
Muller, S., Prowse, D. L., & Soper, M. E. (2012, September 25). CompTIA A+ Cert Guide: Power Supplies and System Cooling | Foundation Topics | Pearson IT Certification. Retrieved March 20, 2014, from http://www.pearsonitcertification.com/articles/article.aspx?p=1945640
An Investigation Into How the Thickness of Insulation Affects the Time a Drink Takes to Cool Down
Electric Cars use the energy stored in a battery (or series of batteries) for vehicle propulsion. Electric motors provide a clean and safe alternative to the internal combustion engine. There are many pros and cons about electric cars. The electric vehicle is known to have faster acceleration. They produce no exhaust.
Pelican products have been made for extreme conditions and are being used in defence, emergency services and expeditions in extremely remote areas. These coolers are now available to you.
[5] Borgnakke, C., Sonntag, R., 2008, “Fundamentals of Thermodynamics, 7th edition,” John Wiley & Sons, Inc., Hoboken.
One of the greatest accomplishments and innovations of human history thus far is the invention of the electric refrigerator. Such a simple concept has literally changed how the entire world stores food and has saved millions of lives in the process. Refrigeration as we know it has only been around since the 1930’s, and in less then a hundred years has been greatly taken for granted. Since the influence of electrical engineering in the modern refrigerator, refrigeration has gone from storing food in an ice cellar to being able to have two dedicating refrigeration units with controllable temperatures and even an ice machine attached. Without electricity modern refrigeration would be drastically different, using instead previous refrigeration
good emitter of heat radiation so a lot of heat will be lost to the
Refrigeration Refrigeration is defined as “The process of removing heat from an enclosed space, or from a substance, to lower its pressure.” (First website given in bibliography) In simpler terms, it is removing heat from states of matter in order to keep them cooler. The basic need for refrigeration is to cool food and beverages, as they often get spoilt if the temperature is high. Before actual refrigerators and other such mechanical systems were introduced, it was very common for people to cool their food with ice and snow.
Saini, Keshav. "Solar Thermal Energy Pros and Cons | Environmental Issues." Environmental Issues Blog. N.p., 6 Jan. 2012. Web. 04 Mar. 2014. .
In this case study I will be discussing advantages and disadvantages of electric cars. Electric cars are cars that are powered by electricity. Electric vehicles are an important part of cutting emissions and reducing global warming. The battery of an electric car stores electrical energy. The electric motor is coupled to the wheels through gears; it converts 59-60% of electrical energy into the wheels. The battery runs the motor which allows the car to move. Electric cars are necessary as they will save money, because electricity is cheaper than gas. Also electric vehicles will help reduce global warming and pollution. However, some people say that electric cars still have environmental costs. The electricity used to recharge EV batteries has to come from somewhere in the world, and now, most electricity is generated by burning fossil fuels. Although electric vehicles are classified as green cars, purists will not appreciate the toxicity of the batteries.
Engineers’ main job is to solve problems and design things that make people’s life easier. One of the problems refrigeration engineers had to deal with at the beginning of the 20th century was how to ma...
Most people today fill up their car with different qualities of petrol, because that's what the average car takes. They don't usually consider an alternative for the petrol that they load into their cars. Although petrol is widely used, it is not the only source for a car to get its power from; diesel and electricity are alternatives to the general petrol used by most cars. Although different from each other, diesel and electricity are alternatives to the average gasoline received at a gas station. Diesel is a more concentrated type of fuel that is usually used by big automobiles because they require a lot of power in a little amount of time. Electricity is a method that uses the power of batteries to produce a low horsepower but, nevertheless fast automobile. Electric cars are generally created to be soundless and environment friendly. The purpose of this paper is to classify and educate the reader of the different types of fuel available for an automobile to use: petrol, diesel, and electricity. The general petrol, used by most people, is usually the only type of fuel accepted on the average car in the United States today.
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.
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...