REVIEW OF LITERATURE
2. 1 Introduction
In research of applied thermo dynamics even while we've been observing heat copy from a system at higher temperatures compared to that at lower temp. Now in the study of refrigeration we are observing various methods of cooling the items and maintaining the temperatures of body at values lower than surrounding temps.
According to American modern culture of Heating up, Refrigeration and Air-conditioning Technical engineers (ASHARE) Refrigeration is the technology of providing and retaining heat below that of the encompassing (ambient) temperature.
In the olden days around 2500 years B. C. Indians, Egyptians, etc. , were producing snow by keeping water in the porous posts open to cool atmosphere during the night period. The evaporation of water in almost cool dried out air followed with recitative warmth transfer in the clear nighttime caused the forming of ice even when the ambient heat range was above the freezing temp. Further references can be found which support the use of ice in China 1000 years BC. Nero, the emperor, was using snow for cooling beverages. Further, the East Indians were able to produce refrigeration by dissolving salt in water as soon as 4th century A. D. , of course, on very small scale. The usage of evaporative cooling down is another software of refrigeration used olden days. The chilling of drinking water in earthen pots for drinking purpose; is the most typical example where the evaporation for drinking water through the skin pores of earthen pot is supported with cooling of drinking water.
The fore said ways of the production of cooling weren't simple for the commercial use scheduled to very small amount of ice production. Option of natural glaciers in limited areas and unavailability of good quality insulation limited the application of ice to those localities only. These all led to the introduction of artificial refrigeration aspect, a few would be provided here. Thomas Harris and John Long got the earliest British parent in 1790. Down the road in 1834 Jacob Perkins developed palm operated refrigeration system using ether (volatile) as the working liquid. Ether vapor is sucked by the hand-operated compressor and then high temperature and pressure either vapor is condensed in this cooled chamber (condenser). Water ether is finally throttled to the lower pressure, and therefore evaporation of the water in chamber A decreases the temperature of water adjoining the vessel. Finally ice is made. In this technique, ether is utilized over and over in the cyclic process with negligible wastage.
In 1851, Dr. John Garrie of Florida, a physician obtained the first American patent of your frosty air machine to create ice in order to get rid of people suffering from the high fever. Instead of air or ether, sulphuric ether was used by Dr. Wayne Harrison of Australia in 1860, the worlds first installation of refrigeration machine for brewery. The steam engine works as a vitality source which drives the compressor for the pressurization of sulphuric ether vapor, which is, in turn, condensed and is also allowed to expand and evaporate in order to produce refrigeration. Dr. Alexander Kirk of England constructed a cold air machine is 1861 similar compared to that of Dr. Gorrie. Air was compressed by way of a reciprocating compressor motivated by a vapor engine operating on coal. His genuine machine used about 1 kg of coal to produce 4 kg of ice (around).
In the 19th century, there was tremendous development of refrigeration systems to displace natural glaciers by artificial snow producing machines. Alas steam engine, an extremely low speed electricity developing source, was used to drive the compressor, making very poor performance of the refrigeration system.
Some Recent Developments of in Refrigeration
In the start of 20th century, large size refrigeration machines were under progress. By 1904 about 450 ton cooling system for air conditioning the brand new York Stock Exchange was installed. In Germany people used air-con in theatre for comfort purposes. In around 1911 the compressor rate grew up between 100 to 300 rpm. The first two-stage modem compressor was brought under use within 1915.
During the civil warfare there is an acute shortage of the supply of natural ice from the north. Hence, Ferdinand Care of the USA developed vapour-absorption refrigeration system ammonia as a refrigerant and water as a absorbent. The system consists of an evaporator, an absorber, a pump, a generator, a condenser and an extension device. The evaporated vapor is assimilated by the weak ammonia-water mixture in the absorber yielding strong aqua ammonia. The pump gives this strong solution into the generator where heat transfer from a burner separates ammonia vapor and the vulnerable ammonia water profits to the absorber. Alternatively the ammonia vapor condenses in the condenser before being throttled. The throttled ammonia water gets into the evaporator resulting in completion of the cyclic process.
In the beginning of 2 decades of the twentieth century, the development in refrigeration system was restricted to refinement in cool air machines and vapor compression thermoelectric, pulse tube refrigeration systems, etc. The trends are vortex pipe, steam-jet refrigeration system, option of materials of specific properties for thermoelectric materials. The possible use of waste products heat or solar technology in case of vapor-absorption and thermoelectric systems has resulted in development of several commercial items nowadays especially because of the like hood of future energy problems, the world will face.
A condenser is a high temperature exchanger is which de-superheating of temperature vapor changes the phase from vapor to liquid and sub cooling down of condensate occurs. The condenser is an important device found in the high pressure side of a refrigeration system. Its function is to remove warmth of hot vapor refrigerant discharged from the compressor. The hot vapor refrigerant contains the heat consumed by the evaporator and heat of compression added by the mechanical energy of the compressor motor. The heat from the hot vapor refrigerant in a condenser is removed first by transferring it to the wall space of the condenser pipes and then from the tubes to the condensing or chilling medium. The cooling medium may be air or normal water or a combination of the two. An air cooled condenser is one in which the removal of warmth is done by air. It includes metal or copper tubing through which the refrigerant moves. How big is tube usually runs from 6mm to 18mm external diameter, depending upon the size of the condenser. Generally copper tubes are used because of its excellent heat copy capability. The condensers with metallic tubes are being used in ammonia refrigerating systems. Most the local refrigerators uses the natural convection air cooled condenser. The present work refrigerator uses the natural convection air cooled condenser. In natural convection air cooled condenser, heat transfer from the condenser coils to the air is by natural convection. As the environment touches the warm condenser pipes, it absorbs temperature from the refrigerant and therefore the temps of air boosts. The heated air being lighter, rises up and cool air from below increases to take away the heat from the condenser. This circuit proceeds in natural convection air cooled condensers. This work is an experimental method of increase the heating to be turned down in the condenser as well as boost the performance of the machine. In case the condenser is having more fins spacing then the number of fins available at the condenser are less. Because of this surface area lessens. Therefore less high temperature transfer occurs. Alternatively if the condenser is having less fins spacing then your variety of fins available at the Condensers will be more. Therefore more temperature rejection takes place in the condenser. Due to more heating rejection sub cooling occurs at the exit of the condenser which escalates the performance of the system.
Decreasing energy ingestion and increasing efficiency is one of the most important points in our era. Learning to be a matter of primary importance in air-con, industrial and commercial cooling down applications, supermarket cooling, blast freezing and process cooling applications, energy efficiency influences design of chillers (and its own equipment such as condensers, compressors etc. ) and urges manufacturers to build up powerful, energy-efficient, environment friendly, economic, and extended life products.
Becoming a subject of principal importance in air conditioning, industrial air conditioning, supermarket chilling, commercial chilling, blast freezing and process cooling applications, etc. , energy efficiency influences the design of chillers that account for a significant percentage of the vitality consumption in vegetation. Legal legislations that for the brief run limit, and over time prohibit the utilization of liquids of high global warming potential, that are damaging to the ozone part are also important on designs. Since air cooled condensers are among the essential components of air conditioning groups, efforts to really improve their energy efficiency are created incessantly, the related nationwide and international standards are upgraded and limitations on their energy consumptions are always increasing.
Our declaration will present -in the light of the latest relevant standards- specific and comparative information on applications aimed at improving the power efficiency in air cooled condensers, highlighting the importance of energy efficiency in cooling installations.
2. 2 The result of condensation temperatures on capacity
The condensation temperature of the refrigerant is known as to be 6C - 20C above air inlet temperatures for standard purposes. The condensation heat range varies based on the ambient temperature in which the system will operate. This said, the condensation temperature for applications is commonly used as 30-60C.
Factors taken into account for identifying the condensation temperature
- Ambient heat,
- Thermo physical properties of the refrigerant,
- Properties of the picked compressor and
- The proportions of the condenser.
While providing the nominal condenser capacity in condensers according to the Euro vent Standard, the environment inlet temps and condensation heat range are considered as 25C and 40C respectively. In other words, T = 15 C.
A low value should be determined for the temperature differential T, in places of high ambient temperature. For example, while planning for the conditions of Antalya the T value should be selected within the number of 7 - 10 C. For systems that will operate in outdoor conditions in conditions of Turkey, the temps differential should be reduced as one moves from the north to the south and options should be made accordingly. It must always be considered that High Compression Temperatures creates a load on the compressor that reduces efficiency and shortens its useful life. It will be quite beneficial in the design for the condensation heat range to be specified only possible. However, in a few conditions it is not possible to take a low value for the condensation heat range. For example in Midsection East countries where the outdoor heat range is 50C-55C, high condenser temp is inescapable.
The following example shows the compressor absorbed vitality at various condensation temperature ranges and the achieved cooling capacities for a semi-hermetic type HGX4/555-4 model compressor manufactured by BOCK, which uses R134A gas. The chilling gas selected for the example is R134A. As seen from the desk, when the condensation heat rises from 30C to 60C, the compressor pulls 25% more electric power while the cooling down capacity drops by 38. 5%, the COP value lessens by 51% and the a product that is 38. 5% greater can be used to achieve the cooling capacity announced in the look.
2. 3 Tried and True for Millennia
Copper tubing has been around use by civilization for a large number of years, and it's been found present in this inflatable water lines of Old Egypt.
Modern-day residences having copper pipes installed 70 years back are still working well in today's day and require far less to fix and change than alternate methods. If you undertake copper, you will have hardly any maintenance, whereas even stainless steel begins to rust over time, especially if it is not painted or coated.
There are a great variety of uses for copper tubing. If you invest a higher degree into copper, you may well be in a position to easily reclaim your investment with high rates of come back for reuse and recycling for example. Copper is a fantastic renewable resource because it is easily recycled.
Beneficial Characteristics of Copper Tubing
- Proven Longevity
- Comparably Lightweight
- Resistant to Corrosion
- Can Be Produced to Shape
- Largely Nontoxic and Non Carcinogenic
2. 4 Copper Condenser Coils
Condensers are one of the prominent uses of copper tubing. Changing gases into fluids arise at appropriate heat dew point. Copper's fantastic heating copy rates are one of the better choices for achieving this goal, exceeding other temperature transfer tubes materials (such as light weight aluminum in cases like this) by almost 800% while preserving a strong, light structure. Having a higher heat transfer rate renders less total materials necessary for a given space, allowing for more compact, light and portable, and simple condenser applications that lessen back again pressure. CTCG develops condensers with copper tubes, aluminum tubes, and stainless steel tubes, to customer prints--but we highly recommend copper tubes for condenser applications.
2. 5 All Designs Accepted for Review
Whether your coil is, serpentine, coaxial, or completely tailored, all designs are accepted for review. Both hard drawn and annealed, versatile copper tubing acceptable for developing and coiling. Easily outsource development works of custom copper tubes coils or buy bulk loads of custom and non-custom length copper tubes, including level wound coils, normal water tubes and piping, refrigeration tubes, DWV and capillary tubes.
Providing Tubes Coils for Most Industries
Copper matches many industries' highest criteria for excellence; thus we recommend the use of copper for your applications in
- The Aerospace Industry,
- Construction Industry,
- Freon Recycling Industry,
- Medical Industry, and the
- AC & Refrigeration Industry
Most projects can be easily made, including such items as gas turbines, imaginative tasks, diagnostic hardware, in one to four weeks (and sometimes faster). Check our present inventory to see what pipe types can be serviced this month
2. 6 Why Copper
Copper tubes is the perfect material for most applications. Its strength, the convenience with which it is fabricated and soldered, and its high conductivity to heating is invaluable along the way of building homes and industrial buildings, specifically for the refrigeration and air conditioning equipment installed.
Tubing made from copper is mostly of the naturally-sourced materials that are 100% recyclable, so no metallic is lost in reclaiming copper from pipes no longer needed, so that it is a great choice for future years.
