Heat exchangers are devices that provide the flow of thermal energy (enthalpy) between two or more fluids, between a solid surface and a fluid, or between solid particulates and a fluid, at different temperatures. Heat exchanger are used in wide variety of application that involve heating or cooling of a fluid stream of concern, evaporation or condensation of a single or multi component fluid steam, and heat recovery or heat rejection from a system. It mostly use in power production, process, chemical and food industries, electronic, environmental engineering, waste heat recovery, manufacturing industry, air conditioning, refrigeration, space application and vessel. In some heat exchangers, the fluids exchanging heat are in direct contact, …show more content…
The portion of the surface that also separates the fluids is referred to the primary or direct surface. To increase heat transfer area, appendages also known as fins may be intimately connected to the primary surface to provide extended, secondary, or indirect surface. Thus, the addition of fins reduces the thermal resistance on that side and thereby increases the net heat transfer from the surface for the same temperature difference. The heat transfer coefficient can also be higher for fins. (Chapter 17, heat exchangers, by R.K. Shah and D.P. Sekulic from University of Kentucky, Retrieved 28 September 2014 , 15.30 …show more content…
The hot steam at A recovers some of the heat from B. The heat transfer occurs through a separating wall or through the interface between steams. For the regenerators or in storage type heat exchanger, the same flow passage is alternately occupied by one of the two fluids. During the cold fluid flow through the same passage, stored energy will extracted from the matrix and the thermal energy is not transferred through the wall because the hot fluid stores it in the matrix. This cycle have showed in figure 2, when the solid is in the cold steam A, it loses heat and difference in the hot steam, it will gains
Two equations were used in this experiment to determine the initial temperature of the hot water. The first equation
When there is a heat exchange between two objects, the object’s temperature will change. The rate at which this change will occur happens according to Newton’s Law of heating and cooling. This law states the rate of temperature change is directly proportional between the two objects. The data in this lab will exhibit that an object will stay in a state of temperature equilibrium, unless the object comes in contact with another object of a different temperature. Newton’s Law of Heat and Cooling can be understood by using this formula:
Convection is a transfer of internal energy into or out of an object by the physical movement of a surrounding fluid that transfers the internal energy along with its mass. According to Oxford Dictionary, convection is the movement caused within a fluid by the tendency of hotter and therefore less dense material to rise, and colder or denser material to sink under gravity's influence, that results in transfer of heat. Two fluids are liquid and gas.The fluid above a hot surface expands, becomes less dense, and rises.This applies to objects such as steam from a hot cup of coffee turning cool, ice melting like heat moving to ice from the air, or frozen material becoming raw like how frozen food thaws more quickly under cold running water. When
Refrigeration, the production of cold, is an essential practice for present-day living. It is used in a many place like the processing and preservation of food, conditioning of air for comfort, manufacture of chemicals and other materials, cooling of concrete, medical applications etc. Refrigeration is defined as the science of maintaining the temperature of a particular space lower than its surrounding space. Refrigeration and air conditioning involves various processes such as compression, expansion, cooling, heating, humidification, de-humidification, air purification, air distribution etc. In all these processes, there is an exchange of mass, momentum and energy. All these exchanges are subject to certain fundamental laws. Hence to understand and analyses the refrigeration and air conditioning systems, a basic knowledge of the laws of thermodynamics, fluid mechanics and heat transfer is essential.
Water is heated in the first container (1) which produces steam. The steam carries heat, called latent heat. A pump on the wall of the first container (1) pumps the steam into the second container (2). The steam from the first container (1) heats the syrup and boils it, creating sugar crystals, in the second container (2), using up the latent heat in the steam from the first container (1). The evaporating syrup creates it's own steam, with latent heat as well. A pump on the opposite wall of the second container, (2), pumps the latent heat in the steam into the third container (3).
Latent heat thermal storage is an alternative to the sensible heat system. This system operates by making use of the ability of the material to store energy through its ability to phase change from solid to liquid or liquid to solid. (Sharma, Tyagi, Chen, & Buddhi, 2009). The process relies on the chemical properties of the chosen material where heat is absorbed or release as the material undergoes a phase change from solid to liquid or vice versa. (Sharma, Tyagi, Chen, & Buddhi, 2009). The process starts when the temperature reaches the required temperature-phase change temperature- and stays constant until the whole process change is finished. Most of the latent heat thermal storage systems are currently based on solid to liquid transition.
Conduction, convection and radiation are the three methods through which heat can be transferred from one place to another. The (www.hyperphysics.com) first method is the conduction through which heat can be transferred from one object to another object. This process is defined as the heat is transmitted from one to another by the interaction of the atoms and the molecules. The atoms and the molecules of the body are physically attached to each other and one part of the body is at higher temperature to the other part or the body, the heat begins to transfer. A simple experiment through which conduction can be understood easily is as follows. First of all, take a metallic rod of any length. Hold the rod in the hand or at any stand made up of the insulator so that the heat does not transfer to the stand. Heat up the one end of the rod with the help of the spirit lamp. After sometime, touch the other end of the end, the other end of the becomes heated too and the temperature of the other end of the rod has also increased. Although only one end of the rod is heated with the spirit lamp, but the other end of the rod has also been heated. This is represents that the heat has been transferred from one end of the rod to the other end of the rod without heating it from the other end. So, the transformation of the heat is taking place. This process is called the conduction. Conduction is a process which is lead by the free electrons. As the conduction happens occurs only in the metallic materials, the reason for it is that the metals has the free electrons and they can move freely from one part of the body to another part of the body. These electrons are not bounded by the nucleus so, they can move ea...
Conduction, convection and radiation are the three methods through which heat can be transferred from one place to another. The (www.hyperphysics.com) first method is the conduction through which heat can be transferred from one object to another object. This process is defined as the heat is transmitted from one to another by the interaction of the atoms and the molecules. The atoms and the molecules of the body are physically attached to each other and one part of the body is at higher temperature to the other part or the body, the heat begins to transfer. A simple experiment through which conduction can be understood easily is as follows. First of all, take a metallic rod of any length. Hold the rod in the hand or at any stand made up of the insulator so that the heat does not transfer to the stand. Heat up the one end of the rod with the help of the spirit lamp. After sometime, touch the other end of the end, the other end of the becomes heated too and the temperature of the other end of the rod has also increased. Although only one end of the rod is heated with the spirit lamp, but the other end of the rod has also been heated. This is represents that the heat has been transferred from one end of the rod to the other end of the rod without heating it from the other end. So, the transformation of the heat is taking place. This process is called the conduction. Conduction is a process which is lead by the free electrons. As the conduction happens occurs only in the metallic materials, the reason for it is that the metals has the free electrons and they can move freely from one part of the body to another part of the body. These electrons are not bounded by the nucleus so, they can move easily. And when the temperature of the ...
Colorimetry is the process of determining the concentration of a substance of a substance by measuring the relative of light. The instrument used is called a calorimeter. Colorimetry is the scientific method that is used to classify the colours of the spectrum.
Heat is thermal energy being transferred from one place to another, because of temperature changes. This can take place by three processes. These three processes are known as conduction, convection, and radiation.
Peoples are always trying different techniques to beat the scorching heat, specifically in summer season. Recently, there many methods that proved their quality in reducing the atmospheric temperature to the required rates. There are three main types of evaporative cooling systems which are sprinkler systems, pad systems and Fogger systems. This project interested in the last one. Fogger system is defined as a type of nozzles that sprays water with high-pressure (up to 200 psi) or low pressure (less than 50 psi) to the air as a fine fog or mist. These fine fog or mist evaporates into the outdoor air in order to cool this air which is located beside the fogger (Giacomelli, 2003).
... temperature of 112 0C also and a pressure 2.5 bar. Cooling water is used to condense the vapor exiting column. Remaining methane and hydrogen are separated in reflux drum where the vapor stream is combined with other gases streams. The overhead of first and second separator are combined to form fuel gas. The liquid stream exiting in the bottoms of the reflux drum is pumped at pressure of 3.3 bar for discharging pressure. The pump stream is separated in two streams. One stream is to feed to tray one of the column and the other one stream is cooled down to 38 0C in heat exchanger. Then, the cooled product stream is sent to storage.
Process da: This low temperature liquid then enters the evaporator where it absorbs heat from the space to be cooled namely the refrigerator and becomes vapour
A steam turbine's two main parts are the cylinder and the rotor. As the steam passes through the fixed blades or nozzles it expands and its velocity increases. The high-velocity jet of steam strikes the first set of moving blades. The kinetic energy of the steam changes into mechanical energy, causing the shaft to rotate. The steam then enters the next set of fixed blades and strikes the next row of moving blades. As the steam flows through the turbine, its pressure and temperature decreases, while its volume increases. The decrease in pressure and temperature occurs as the steam transmits energy to the shaft and performs work. After passing through the last turbine stage, the steam exhausts into the condenser or process steam system. The kinetic energy of the steam changes into mechanical erringly through the impact (impulse) or reaction of the steam against the blades.
Fluid motion over the objects surface is inducted by mechanical means. This is externally introduced by way of a pump or fan.