PART A
TITAL OF MICRO PROECT :- PREPARE REPORT ON REFRIGERATION AND AIR
CONDITIONING
Brief Introduction :
REFRIGERATION :In air refrigeration, the air is used as a refrigerant. In olden days, air was widely used in commercial applications because of its availability at free of cost.Since air does not change its phase i.e. remains gaseous throughout the cycle,therefore the heat carrying capacity per kg of air is very small as compared to vapour absorbing systems
AIR CONDITIONING:-The air conditioning is that branch of engineering science which deals with the study of conditioning of air i.e. supplying and maintaining desirable internal atmospheric condition for human comfort, irrespective of external condition.
Aim of micro project :
1 . Prepare technical report
2.show the attitude of enquiry
3.work independently for responsibility
4.participate effectively in group work
5.work persistently achieve the target
Part B
Title :- “PREPARE REPORT ON REFRIGERATION AND AIR CONDITIONING‘ ’
Aims/Benefits of the Micro-Project :-Refrigeration may be defined as the process of reducing and maintaining a temperature of a space or material below that of the surroundings. This is accomplished by removing heat from the body being refrigerated and transferred it to another body whose temperature is higher than that of the refrigerated body or space. It is evident that refrigerating and heating are actually opposite ends of the same process. Often, it is the desired result that distinguishes one from the other. Refrigeration is basic to the heating, ventilation and air conditioning industry. One of the most important applications of refrigeration has been the preservation of perishable food products, food processing, packaging, storing and transportation by storing them at low temperatures. The effect of storage temperature on useful storage life of food products is given in Table 1 . Refrigeration systems are also used extensively for providing thermal comfort to human beings by means of air conditioning. Air Conditioning refers to the treatment of air so as to simultaneously control its temperature, moisture content, cleanliness, odour and circulation, as required by occupants, a process, or products in the space. The subject of refrigeration and air conditioning has evolved out of human need for food and comfort. The purpose of refrigerator is to transfer heat from a cold chamber which is at a lower temperature than that of its surrounding. .
Course outcome :-
1 .Illustrate the fundamental principles and applications of refrigeration and air conditioning system
2. Obtain cooling capacity and coefficient of performance by conducting test on vapour compress ion refrigeration systems
3.Present the properties, applications and environmental issues of different Refrigerents
4.Calculate cooling load for air conditioning systems used for various
5. Operate and analyze the refrigeration and air conditioning systems.
Output of micro project
Identity the refrigeration and air conditioning
Increase knowledge about refrigerator and air conditioning
Increase communication skill
Ex perience team work
Ability the face all problems
Skill developed in micro project :- .
1 . Learning the fundamental principles and different met hods of refrigerat ion and air
cond it ioning.
2. St udy of various refrigerat ion cycles and evaluate performance using Mollier chart s and/ or
refrigerant property tables.
3. Comparat ive st udy of different refrigerants wit h respect to propert ies, applicat ions and
environment al issues.
4. Underst and the basic air cond it ioning processes on psychomet ric charts, calculate cooling
load for its applicat ions in comfort and indust rial air cond it ioning.
5. St udy of t he various eq uipment-operat ing principles, operat ing and safety controls
em ployed in refrigerat ion air conditioning system
6.Principle of refrigeration and air conditioning:-
REFRIGERATION :- The principle of refrigeration is based on second law of thermodynamics. It satest hat heat does not flow from a low temperature body to a high temperature body without the help of an external work. In refrigeration process, since the heat has to Hot Body be transferred from a low temperature body to a high temperature body some external work has to be done according to the second law of work shown thermodynamics as work shown. This external work is done by means of input compressor, condenser etc. Refrigerator The machine, which works under this principle and serves the purpose of refrigeration is called a Refrigerator.
AIR CONDITIONING :-First, an air conditioning system serves several purposes. We do have air-conditioners in our homes, offices, cars and elsewhere, used for providing a cool and dry atmosphere. Although the air conditioning process provides cool air, its primary purpose, as the term describes, is for conditioning the air (or atmosphere) to that is comfortable for humans.Air conditioning has evolved with time. A foretime, men invented various mechanisms for the aim of accomplishing this purpose. Modern air-conditioning works with the principle of thermodynamics. They literally helps in the transfer of heat within areas.This article provides information on the working principle of the air-conditioning system. A very basic air-conditioner constitutes some components working in a cycle toachieve the aim. This parts function to actualizing the operation. Proper understandings of the role they play enable one to correctly determine the principles of the working of an air-conditioner.
APPLICATIONS :-
Application of refrigerating :-
1 .A refrigerator is an insulated box in which low temperature is maintained to facilitate
sa lt or medium-term storage of food.
2.The refrigerator is usually specified as per volumetric capacity on the inside.
3.It is available in the capacity of 65 liters, 1 00 liters, 1 65 liters, 275 liters, to double door
refrigerator of capacity as large as 1 000 liters.
4.Large size refrigerator comes with independent compart ments as per food categories.
5.So you get freezer cabinet, vegetable pulls out compartment and so on.6.Most of the
refrigerator comes with painting Stell sheet cabinet on the outside with strong industrial
plastic inner cabinet for rust proofing shown in the figure.
7.In early refrigerators, cork expanded polystyrene ( Thermocol ) sheets or granules
were used for insulat ions.
8.But nowadays polyurethane foam is the most common insulation used in in the
refrigerator.
9.The door of the cabinet is provided with a neoprene rubber gasket to prevent leakage
of air from t he cabinet.
10.The inner cabinet and the inner panel of the door are suitably formed to provide trays
fo r different cat egories of food.
11 .Small refrigerator 1 65 liters the circulation of air for cooling is by natural convection.
12.This allows a range of temperature from -20 degree Celsius in the freezer cabinet at
the top to about 5 degree Celsius in the vegetable tray located at the bottom.
13.The trays are not solid to allow air flow through the trays for circulation of air.
14.The temperature is maintained within a range by cyclic control.
15.The compressor cuts off at lower end i.e cut off temperature and restarts at Higher
end i.e cut in temperature.
Application of air conditioning:
1 .Air conditioning can be defined as conditioning the air for a natural and comfortable atmosphere within the living area, particularly office.
2.Filtering air for dust particles, mould, insects, and many other micro organism living in air.
3.Employed in large supercomputer halls to small desktops rooms for keeping them their cool and for their prolonged working.
4. Constant temperature is to be maintained in the tool room as you know metal are not so trusted with changing temperature for their dimensions.
5.Air conditioning helps the shop owners for a good sale. Or maybe that is why we hang out in malls more often in college days.
6.Air conditioner keeps the boss cool in office. Just imagine what it would be like a sweaty red boss.
7.Air conditioners can keep your food fresh for a little longer. Sometimes even for 2 year in cold rooms.
8. Air conditioner is used in Operation theatre so that patients could get well soon other than getting his wounds septic due to the microorganisms present in air, which as stated, in a condition without AC
9.Did mentioned that ACs are used in car and another such vehicle for the comfort of the rider. Airplane too.
10. Testing rooms are generally air conditioned.
ELEMENTS OF REFRIGERATION AND AIR CONDITIONING :-
Refrigeration:-
Compressor: The function of the compressor is to compress the input refrigerant of low pressure and low temperature. As a result the pressure and the temperature of the refrigerant increases. Generally reciprocating compressors are used in a refrigeration system. An external motor is used to drive the compressor.
2. Condenser: The condenser is a coil of tubes, which are made of copper. This is used to condense the refrigerant which is in the form of vapor. And convert into liquid.
3. Expansion Valve: this is otherwise called throttle valve. This valve is used to control the flow rate of refrigerant and also to reduce the pressure of the refrigerant.
4. Evaporator: This is the part in which the cooling takes place. This is kept in the space where cooling is required. It is a coil of tubes made up of copper..
Air conditioning :-
1 . Circulation fan
2. Compressor
3. Condenser
4. Dryer
5. Evaporator
6. Supply Duct
7. Supply outlet
8. Return outlet
9. Filters
ADVANTAGES OF REFRIGERATOR :-
The basic advantage of air refrigeration is the working substance which is always available in the atmosphere.The refrigerant (air) is free of cost and the system is simple to understand. The refrigerant keeps the container cool by breaking the bacterial involvement. There is no danger of fire due to the leakage of refrigerant from the pipes(if any).
DISADVANTAGES OF REFRIGERATOR:-
The running cost of t he refrigeration is high because the Coefficient of Performance(C.O.P) is very low. Per One Tonne of refrigeration, the quantity of refrigerant used is high compared to systems. In Environment, as the air contains moisture which can affect the danger of frosting at the valves.
ADVANTAGES OF AIR CONDITIONING :-
Most people use air conditioners to stay more comfortable in their homes or offices during hot and humid summer weather. Under extreme conditions, air conditioners may keep elderly and other vulnerable people safer from heat-induced health problems. Air conditioners are used in many commercial settings not only for increased comfort but for decreasing heat stress on delicate machinery such as computers, and reducing food spoilage in grocery stores and restaurants.
DISADVANTAGES OF AIR CONDITIONING:-
Air conditioners use a lot of electricity. This creates both financial disadvantages for the people who have to pay for the power, and more generalized environmental disadvantages caused by power production. Because a large percentage of electricity is created by coal-burning power plants, air conditioning contributes indirectly to the release of greenhouse gases and other pollutants. In addition, according to The Independent, spending too much time in an air-conditioned environment can contribute to health problems such as asthma, tightness in the chest and other respiratory ailments.
