Internal Combustion Engine It is an engine that generates motive power by the burning gasoline, oil, or other fuel with air inside the engine, the hot gases produced being used to drive a piston or do other work as they expand. This force moves the component over a distance, transforming chemical energy into useful mechanical energy. of The first commercially successful internal combustion engine was created by Étienne Lenoir around 1859 and the first modern internal combustion engine was created in 1876 by Nikolaus Otto. Internal Combustion Engines (ICE) are the most common form of heat engines, as they are used in vehicles, boats, ships, airplanes, and trains. They are named as such because the fuel is ignited in order to do work inside the engine. The same fuel and air mixture are then emitted as exhaust. How does this engine work? Combustion, also known as burning, is the basic chemical process of releasing energy from a fuel and air mixture. In an internal combustion engine (ICE), the ignition and combustion of the fuel occurs within the engine itself. The engine then partially converts the energy from the combustion to work. The engine consists of a fixed cylinder and a moving piston. The expanding combustion gases push the piston, which in turn rotates the crankshaft. Ultimately, through a system of gears in the powertrain, this motion drives the vehicle’s wheels. There are two kinds of internal combustion engines currently in production: the spark ignition gasoline engine and the compression ignition diesel engine. Most of these are fourstroke cycle engines, meaning four piston strokes are needed to complete a cycle. The cycle includes four distinct processes: intake, compression, combustion and power stroke, and exhaust. Spark ignition gasoline and compression ignition diesel engines differ in how they supply and ignite the fuel. In a spark ignition engine, the fuel is mixed with air and then inducted into the cylinder during the intake process. After the piston compresses the fuel-air mixture, the spark ignites it, causing combustion. The expansion of the combustion gases pushes the piston during the power stroke. In a diesel engine, only air is inducted into the engine and then compressed. Diesel engines then spray the fuel into the hot compressed air at a suitable, measured rate, causing it to ignite. Diesel Engine Like a gasoline engine, a diesel engine is a type of internal combustion engine. Combustion is another word for burning, and internal means inside, so an internal combustion engine is simply one where the fuel is burned inside the main part of the engine (the cylinders) where power is produced. That's very different from an external combustion engine such as those used by old-fashioned steam locomotives. In a steam engine, there's a big fire at one end of a boiler that heats water to make steam. The steam flows down long tubes to a cylinder at the opposite end of the boiler where it pushes a piston back and forth to move the wheels. This is external combustion because the fire is outside the cylinder (indeed, typically 6-7 meters or 2030ft away). In a gasoline or diesel engine, the fuel burns inside the cylinders themselves. Internal combustion wastes much less energy because the heat doesn't have to flow from where it's produced into the cylinder: everything happens in the same place. That's why internal combustion engines are more efficient than external combustion engines (they produce more energy from the same volume of fuel). How does a Diesel Engine work? A diesel engine works differently from a petrol engine, even though they share major components and both work on the four-stroke cycle. The main differences are in the way the fuel is ignited and the way the power output is regulated. In a petrol engine, the fuel/air mixture is ignited by a spark. In a diesel engine, ignition is achieved by compression of air alone. A typical compression ratio for a diesel engine is 20:1, compared with 9:1 for a petrol engine. Compressions as great as this heat up the air to a temperature high enough to ignite the fuel spontaneously, with no need of a spark and therefore of an ignition system. A petrol engine draws in variable amounts of air per suction stroke, the exact amount depending on the throttle opening. A diesel engine, on the other hand, always draws in the same amount of air (at each engine speed), through an unthrottled inlet tract that is opened and closed only by the inlet valve (there is neither a carburetor nor a butterfly valve). When the piston reaches the effective end of its induction stroke, the inlet valve closes. The piston, carried round by the power from the other pistons and the momentum of the flywheel, travels to the top of the cylinder, compressing the air into about a twentieth of its original volume. As the piston reaches the top of its travel, a precisely metered quantity of diesel fuel is injected into the combustion chamber. The heat from compression fires the fuel/air mixture immediately, causing it to burn and expand. This forces the piston downwards, turning the crankshaft. As the piston moves up the cylinder on the exhaust stroke, the exhaust valve opens and allows the burned and expanded gases to travel down the exhaust pipe. At the end of the exhaust stroke the cylinder is ready for a fresh charge of air. Gas or Petrol Engine A gasoline engine is a type of heat engine, specifically an internal combustion, that is powered by gasoline. These engines are the most common ways of making motor vehicles move. While turbines can be powered by gasoline, a gasoline engine refers specifically to piston-driven gasoline engines. Gasoline engines are a lot of the reason why the world takes so much oil out of the ground to refine into petroleum products like gasoline. Worldwide, transportation is roughly 18% of our primary energy use and gasoline is a little less than half of that.[2] This means that gasoline engines use roughly 8% of the total primary energy of the world. How does a Gasoline or Petrol Engine work? Spark ignition gasoline and compression ignition diesel engines differ in how they supply and ignite the fuel. In a spark ignition engine, the fuel is mixed with air and then inducted into the cylinder during the intake process. After the piston compresses the fuel-air mixture, the spark ignites it, causing combustion. The expansion of the combustion gases pushes the piston during the power stroke. In a diesel engine, only air is inducted into the engine and then compressed. Diesel engines then spray the fuel into the hot compressed air at a suitable, measured rate, causing it to ignite. Gasoline Engine Steam Turbine In general, a steam turbine is a rotary heat engine that converts thermal energy contained in the steam to mechanical energy or to electrical energy. In its simplest form, a steam turbine consist of a boiler (steam generator), turbine, condenser, feed pump and a variety of auxiliary devices. Unlike with reciprocating engines, for instance, compression, heating and expansion are continuous and they occur simultaneously. The basic operation of the steam turbine is similar to the gas turbine except that the working fluid is water and steam instead of air or gas. Since the steam turbine is a rotary heat engine, it is particularly suited to be used to drive an electrical generator. Note that about 90% of all electricity generation in the world is by use of steam turbines. Steam turbine was invented in 1884 by Sir Charles Parsons, whose first model was connected to a dynamo that generated 7.5 kW (10 hp) of electricity. Steam turbine is a common feature of all modern and also future thermal power plants. In fact, also the power production of fusion power plants is based on the use of conventional steam turbines. How does a Steam Turbine work? The thermal energy contained in the steam is converted to the mechanical energy by expansion through the turbine. The expansion takes place through a series of fixed blades (nozzles), that orient the steam flow into high speed jets. These jets contain significant kinetic energy, which is converted into shaft rotation by the bucket-like shaped rotor blades, as the steam jet changes direction. The steam jet, in moving over the curved surface of the blade, exerts a pressure on the blade owing to its centrifugal force. Each row of fixed nozzles and moving blades is called a stage. The blades rotate on the turbine rotor and the fixed blades are concentrically arranged within the circular turbine casing. In all turbines the rotating blade velocity is proportional to the steam velocity passing over the blade. If the steam is expanded only in a single stage from the boiler pressure to the exhaust pressure, its velocity must be extremely high. But the typical main turbine in nuclear power plants, in which steam expands from pressures about 6 MPa to pressures about 0.008 MPa, operates at speeds about 3,000 RPM for 50 Hz systems for 2-pole generator.(or 1500RPM for 4-pole generator), and 1800 RPM for 60 Hz systems for 4-pole generator (or 3600 RPM for 2pole generator). A single-blade ring would require very large blades and approximately 30 000 RPM, which is too high for practical purposes. Therefore, most of nuclear power plants operates a single-shaft turbine-generator that consists of one multi-stage HP turbine and three parallel multi-stage LP turbines, a main generator and an exciter. HP Turbine is usually double-flow reaction turbine with about 10 stages with shrouded blades and produces about 30-40% of the gross power output of the power plant unit. LP turbines are usually double-flow reaction turbines with about 5-8 stages (with shrouded blades and with free-standing blades of last 3 stages). LP turbines produce approximately 60-70% of the gross power output of the power plant unit. Each turbine rotor is mounted on two bearings, i.e. there are double bearings between each turbine module. Gas Turbine A gas turbine is a type of turbine that uses pressurized gas to spin it in order to generate electricity or provide kinetic energy to an airplane or jet. The process to do so is called the Brayton cycle. In all modern gas turbines, the pressurized gas is created by the burning of a fuel like natural gas, kerosene, propane or jet fuel. The heat generated by this fuel expands air which flows through the turbine to supply useful energy. How does a Gas Turbine work? Gas turbines are theoretically simple, and have three main parts: 1. Compressor- Takes in air from outside of the turbine and increases its pressure. 2. Combustor- Burns the fuel and produces high pressure and high velocity gas. 3. Turbine- Extracts the energy from the gas coming from the combustor. Compressor In Figure, air is sucked in from the left and input to the compressor which consists of many rows of fan blades. In some turbines, the pressure of the air can increase by a factor of 30. Combustor The high-pressure air flows into this area, which is where the fuel is introduced. The fuel gets injected constantly into this part in order for the energy through the turbine to be constant. Turbine The turbine is connected to the compressor blades by a shaft, and they spin separately. The compressor connects to the turbine which is connected to an output shaft, and because the turbine spins separately, it can get up to tremendous speeds due to the hot gas flowing through it. This final shaft generates enormous amounts of horsepower, with large airplane turbines generating nearly 110000 hp - twice the power generated by the Titanic. Condenser Condenser, device for reducing a gas or vapour to a liquid. Condensers are employed in power plants to condense exhaust steam from turbines and in refrigeration plants to condense refrigerant vapours, such as ammonia and fluorinated hydrocarbons. The petroleum and chemical industries employ condensers for the condensation of hydrocarbons and other chemical vapours. In distilling operations, the device in which the vapour is transformed to a liquid state is called a condenser. All condensers operate by removing heat from the gas or vapour; once sufficient heat is eliminated, liquefaction occurs. For some applications, all that is necessary is to pass the gas through a long tube (usually arranged in a coil or other compact shape) to permit heat to escape into the surrounding air. A heat-conductive metal, such as copper, is commonly used to transport the vapour. A condenser’s efficiency is often enhanced by attaching fins (i.e., flat sheets of conductive metal) to the tubing to accelerate heat removal. Commonly, such condensers employ fans to force air through the fins and carry the heat away. In many cases, large condensers for industrial applications use water or some other liquid in place of air to achieve heat removal. How does a Condenser work? The condenser coil is where the heat gets removed. The consolidating unit (some of the time inaccurately known as compressor) is situated outside. Its original capacity is that of a warmth exchanger, in which it gathers a substance (refrigerant) from it’s vaporous to the molten state. From that point, the latent heat is surrendered by the content and will exchange to the condenser coolant. In the refrigeration cycle, a warmth pump transfers warm from a lowtemperature close source into a higher temperature warm sink. Warm streams the other way as a result of the second law of thermodynamics. The most wellknown of the refrigeration cycles utilizes an electric engine to drive a compressor (situated inside the consolidating unit). Since dissipation happens when warmth is retained, and buildup occurs when heat is discharged, aeration and cooling systems are intended to utilize a compressor to cause weight changes between two compartments, and effectively draw refrigerant around. Inside the condenser, the refrigerant vapor is compacted and constrained through a warmth trade loop, gathering it into a fluid and dismissing the heat already retained from the cold indoor zone. The condenser’s heat exchanger is for the most part cooled by a fan blowing outside air through it. Evaporator The evaporator works the opposite of the condenser, here refrigerant liquid is converted to gas, absorbing heat from the air in the compartment. When the liquid refrigerant reaches the evaporator, its pressure has been reduced, dissipating its heat content and making it much cooler than the fan air flowing around it. This causes the refrigerant to absorb heat from the warm air and reach its low boiling point rapidly. The refrigerant then vaporizes, absorbing the maximum amount of heat. This heat is then carried by the refrigerant from the evaporator as a low-pressure gas through a hose or line to the low side of the compressor, where the whole refrigeration cycle is repeated. The evaporator removes heat from the area that is to be cooled. The desired temperature of cooling of the area will determine if refrigeration or air conditioning is desired. For example, food preservation generally requires low refrigeration temperatures, ranging from 40°F (4°C) to below 0°F (-18°C). A higher temperature is required for human comfort. A larger area is cooled, which requires that large volumes of air be passed through the evaporator coil for heat exchange. A blower becomes a necessary part of the evaporator in the air conditioning system. The blower fans must not only draw heat-laden air into the evaporator, but must also force this air over the evaporator fins and coils where it surrenders its heat to the refrigerant and then forces the cooled air out of the evaporator into the space being cooled. How does an Evaporator work? The air conditioners compressor changes the refrigerant gas to a liquid under high pressure. The liquid refrigerant flows into the evaporator through a very tiny orifice. As the liquid enters the evaporator and progresses through its coils, it picks up heat from the air passing through it, causing it to evaporate, thus cooling the room. Refrigeration Refrigeration, or cooling process, is the removal of unwanted heat from a selected object, substance, or space and its transfer to another object, substance, or space. Removal of heat lowers the temperature and may be accomplished by use of ice, snow, chilled water or mechanical refrigeration. Refrigeration is the process of removing heat from an enclosed space, or from a substance, and rejecting it elsewhere for the primary purpose of lowering the temperature of the space or substance and then maintaining that lower temperature. The term cooling refers generally to any natural or artificial process by which heat is dissipated. The field of study that deals with artificial production of extremely low temperatures is referred to as cryogenics. Cold is the absence of heat, hence in order to decrease a temperature, one "removes heat," rather than "adding cold." To satisfy the Second Law of Thermodynamics, some form of work must be performed when removing heat. This work is traditionally mechanical work, but it can also be done by magnetism, laser, or other means. How does a Refrigeration work? 1. The compressor constricts the refrigerant vapor, raising its pressure and temperature, and pushes it into the coils of the condenser on the outside of the refrigerator. 2. When the hot gas in the coils of the condenser meets the cooler air temperature of the kitchen, it becomes a liquid. 3. Now in liquid form at high pressure, the refrigerant cools down as it flows through the expansion valve into the evaporator coils inside the freezer and the fridge. 4. The refrigerant absorbs the heat inside the fridge when it flows through the evaporator coils, cooling down the air inside the fridge. 5. Last, the refrigerant evaporates to a gas due to raised temperature, and then flows back to the compressor, where the cycle starts all over again. The main component of a refrigerator that needs power is the compressor. It is essentially a pump which is driven by a motor. The hum you hear when the fridge is on is that of the compressor working. The thermostat controls the temperature of the fridge by switching onand-off the compressor. Split Type Air Conditioner When someone refers to a split air conditioner, they are referring to the way in which the unit is set up. A split air conditioner is composed of two separate units, a condensing unit and an evaporative coil (known as a “condenser,” and a “coil” respectively in short-hand or slang). It is from these two separate units that a split air conditioner gets its name. These units are joined by a set of copper tubing known as a “line-set,” which transfers refrigerant from one unit to another. A split air conditioner consists of an outdoor unit and an indoor unit. The outdoor unit is installed on or near the exterior wall of the room that you wish to cool. This unit houses the compressor, condenser coil and the expansion coil or capillary tubing. The sleek-looking indoor unit contains the cooling coil, a long blower and an air filter. How does a Split Type Air Conditioner work? A split air conditioner is made up of two primary parts that a very familiar: the evaporator and the compressor. Both of these elements exist is more common central air units and wall air conditioners. The difference with a mini-split system is that they are separated into two different, distant components, one being outdoors and one being indoors. The outdoor section is a compressor that initiates the cooling process, while the indoor component consists of an evaporator and fan. The two sections are connected with a set of electrical wires and tubing, also called lines, used to transport air between the two sections. It's these lines that allow the split AC to be considered ductless, and the fact that the wires and tubing are so small and discreet compared to large ducts is where the "mini" split name comes from. Chiller / Evaporative Condenser An evaporative condenser is used to remove excess heat from a cooling system when the heat cannot be utilized for other purposes. The excess heat is removed by evaporating water. The evaporative condenser has a cabinet with a water-sprayed condenser, and it usually has one or more fans. The excess heat is removed by evaporating water. In an evaporative condenser the primary coolant of the cooling system is cooled, which is the opposite of a cooling tower. Evaporator condensers are more expensive than dry coolers and are primarily used in large cooling systems or systems where the outdoor temperature is high. In many locations around the world, regulations limit the physical size of a cooling system and this in turn limits the use of evaporative condensers. Spraying a condenser with water exploits the fact that the dew point temperature is lower than the air temperature and that a wet surface transfers heat more efficiently. How does a Chiller work? Evaporative Condenser is also named Evaporative Cooler. It’s a type of cooling equipment utilizing the evaporation of partial spray water, to absorb the heat from the flowing gaseous refrigerant of high temperature inside the condensing coils, and cool the refrigerant from gaseous state to liquid form. In an evaporative cooling system, compressor discharges high pressure evaporated refrigerant in gas form, which passes through the heat exchange coils of evaporative condenser, and exchanges heat with spray water outside the heat exchange coils. After entering heat exchange coils from upper inlet, gaseous refrigerant is gradually cooled to be liquid form from top down. The strong wind of fans makes spray water fully cover the heat exchange coil evenly, and this tremendously increases the heat exchange efficiency. Partial calefactive spray water gets vaporized and takes away massive heat with the air flow. Small water drops in hot air are intercepted by highly efficient drift eliminator, collected and fall back to PVC fill together with hot spray water, then gets cooled by flowing air, eventually return to the spray water basin after temperature decreased. This whole process is recycling by the circulating pump when the evaporative condensers are working. The evaporated spray water is made up automatically by water level regulator. Cooling Tower A cooling tower is a heat rejection device, which extracts waste heat to the atmosphere though the cooling of a water stream to a lower temperature. The type of heat rejection in a cooling tower is termed "evaporative" in that it allows a small portion of the water being cooled to evaporate into a moving air stream to provide significant cooling to the rest of that water stream. The heat from the water stream transferred to the air stream raises the air's temperature and its relative humidity to 100%, and this air is discharged to the atmosphere. Evaporative heat rejection devices such as cooling towers are commonly used to provide significantly lower water temperatures than achievable with "air cooled" or "dry" heat rejection devices, like the radiator in a car, thereby achieving more cost-effective and energy efficient operation of systems in need of cooling. Think of the times you've seen something hot be rapidly cooled by putting water on it, which evaporates, cooling rapidly, such as an overheated car radiator. The cooling potential of a wet surface is much better than a dry one. How Does a Cooling Tower work? Cooling towers are a special type of heat exchanger that allows water and air to come in contact with each other to lower the temperature of the hot water. During this process, small volumes of water evaporate, lowering the temperature of the water that’s being circulated throughout the cooling tower. In a short summary, a cooling tower cools down water that gets over heated by industrial equipment and processes. The hot water is usually caused by air conditioning condensers or other industrial processes. That water is pumped through pipes directly into the cooling tower. Cooling tower nozzles are used to spray the water onto to the “fill media”, which slows the water flow down and exposes the maximum amount of water surface area possible for the best air-water contact. The water is exposed to air as it flows throughout the cooling tower. The air is being pulled by an motordriven electric “cooling tower fan”. When the air and water come together, a small volume of water evaporates, creating an action of cooling. The colder water gets pumped back to the process/equipment that absorbs heat or the condenser. It repeats the loop over and over again to constantly cool down the heated equipment or condensers.
