COOLING SYSTEMS
ABSTRACT: In order to maintain good steady conditions of any structure or device either it is mechanical or electrical the fore most important thing is cooling of the systems so as to increase its life and performance. Cooling system is an apparatus or equipment employed to keep the temperature of a structure or device from exceeding limits imposed by needs of safety and efficiency. If overheated, the oil in a mechanical transmission loses its lubricating capacity, while the fluid in a hydraulic coupling or converter leaks under the pressure created. In an electric motor, overheating causes deterioration of the insulation. The pistons in an overheated internal-combustion engine may seize (stick) in the cylinders. Cooling systems are employed in automobiles, industrial plant machinery, nuclear reactors, and many other types of machinery. The cooling agents customarily employed are air and a liquid (usually water or a solution of water and antifreeze), either alone or in combination. In some cases, direct contact with ambient air (free convection) may be sufficient; in other cases, it
may be necessary to employ forced-air convection, created either by a fan or by the natural motion of the hot body. Liquid is typically moved through a continuous loop in the cooling system by a pump.
COOLING SYSTEMS: Cooling system is an apparatus or equipment set up in different systems like automobiles, industrial plant machinery, nuclear reactors, and many other types of machinery so as to maintain the temperature of a system from exceeding limits imposed by needs of safety and efficiency. In addition to this overcooling can have negative effects on the system. Overcooling can reduce the system performance and shorten the systems service life. Cooling systems are used to manage systems heat. Cooling systems must be properly designed, operated and maintained for proper engine operation and service life. HISTORY: The first cooling system was ice harvesting or ice refrigeration. This system is the first cooling system which is implemented by using ice as the working fluid.
Later on in In 1820, British scientist and inventor Michael Faraday discovered mechanical cooling system with ammonia as working fluid. In 1902, the first modern electrical air cooling system unit was invented by Willis Haviland Carrier in Buffalo, New York. NECESSITY OF COOLING SYSTEMS: A cooling system is a part of the engine that prevents engine breakdown due to overheating. All the parts that make up the cooling system have only one purpose and that is to make sure that the circulation of the coolant inside the engine can absorb and release heat. In an aircraft, cooling systems are required to keep the cabin temperatures at a comfortable level. Similar in every heat generating system we need cooling systems in order to obtain a better performance of the system. WORKING OF COOLING SYSTEMS:
These cooling systems work on theory of heat transfer. Heat transfer is a discipline of thermal engineering that concerns the generation, use, conversion, and exchange of thermal energy and heat between physical systems. Mechanism Of Heat Transfer:
Conduction: The transfer of energy between objects that are in physical contact Convection: The transfer of energy between an object and its environment, due to fluid motion Radiation: The transfer of energy to or from a body by means of the emission or absorption of electromagnetic radiation Advection The transfer of energy from one location to another as a side effect of physically moving an object containing that energy METHODS OF COOLING: 1. AIR COOLING
2. WATER COOLING/LIQUID COOLING 3. STEAM COOLING AIR COOLING: Air cooling is a method of dissipating heat. It works by making the object to be cooled have a larger surface area or have an increased flow of air over its surface, or both. An example of the former is to add fins to the surface of the object, either by making them integral or by attaching them tightly to the object's surface (to ensure efficient heat transfer). In the case of the latter it is done by using a fan blowing air into or onto the object one wants to cool. In many cases the addition of fins adds to the total surface area making a heat sink that makes for greater efficiency in cooling.
THE HEAT DISSIPATED DEPENDS UPON FOLLOWING FACTORS: SURFACE AREA OF METAL INTO CONTACT WITH AIR MASS FLOW RATE OF AIR TEMPERATURE DIFFERENCE BETWEEN THE HEATED SURFACE AND AIR CONDUCTIVITY OF METAL ADVANTAGE OF AIR COOLING Lighter in weight because of absence of the radiator the cooling jackets and the coolant.
Can be operated in extreme climates, where water may freeze. Maintenance is easier because the problem of leakage is not there. Engine warms up faster than water cooled engine. Anti-freeze not required.
DIS-ADVANTAGES: Less efficient cooling because the co-efficient of heat transfer of air is less than that of water. Not easy to maintain even cooling all around the cylinder, distortion of cylinder may take place. Air cooled engines are more noisy because of the absence of cooling water which acts as sound insulator. WATER COOLING: Water cooling is a method of heat removal from components and industrial equipment. As opposed to air cooling, water is used as the heat conductor. Water cooling is commonly used for cooling automobile internal combustion engines and large industrial facilities such as steam electric power plants, hydroelectric generators, petroleum refineries and chemical plants. Other uses include cooling the barrels of machine guns, cooling of lubricant oil in pumps; for cooling purposes in heat exchangers; cooling products from tanks or columns, and recently, cooling of various major components inside high-end personal computers. The main mechanism for water cooling is convective heat transfer.
MAIN PARTS OF RADIATOR
UPPER TANK. LOWER TANK. CORE. OVERFLOW PIPE. DRAIN PLUG.
TYPES OF WATER COOLING SYSTEM THERMOSYPHON SYSTEM. PUMP CIRCULATION SYSTEM. COMPONENT OF WATER COOLING SYSTEM
RADIATOR. PRESSURE CAP AND EXPANSION RESERVOIR. THERMOSTAT PUMP FAN AND BELT HOSES WATER JACKETS IN CYLINDER BLOCK AND HEAD
TEMPERATURE GUAGE. TYPES OF RADIATOR TUBULAR TYPE CELLULAR TYPE STEAM JET COOLING: Steam jet cooling uses a high-pressure jet of steam to cool water or other fluid media. Typical uses include industrial sites, where a suitable steam supply already exists for other purposes or, historically, for air conditioning on passenger trains which use steam for heating. Steam jet cooling experienced a wave of popularity during the early 1930s for air conditioning large buildings. Steam ejector refrigeration cycles were later supplanted by systems using mechanical compressors. ADVANTAGES: It is a much more efficient system at detracting heat away from the processor and outside of the system. Another benefit of a liquid cooling is the reduction of noise within the computer. Fans or other cooling system tend to make large and unfavored noises. It increases the efficiency of the system. DISADVANTAGES: A liquid cooling system tends to take over a lot of space. Liquid cooling systems are new to the technical world, so it requires some skills. Even though you could buy a whole kit, it still needs to be custom, seeing that each PC has its own size and such. OVER COOLING may decrease the efficiency of the system. CONCLUSION: In present heat generation systems these cooling systems play a vital role in their performance improvement. So proper utilization of these systems can make the systems to run at economic rates.
