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Heat loss by conduction, convection and radiation
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With the development of society, scientists invent new efficient and effective technologies for humanity to live with comfort, and thermal insulation system is one of these to serve people by reducing undesirable heat loss or gain and decreasing the energy demands of heating and cooling systems. In summer, the amount of heat entering through walls and ceilings is reduced, keeping the home cooler. In winter, insulation helps to keep warmth inside the home.
This article will explain three principles of thermal insulation systems in building, namely conduction, convection and thermal radiation, then discusses three applications in home, finally shows the significance of the thermal insulation systems for humanity.
Generally, Mukherjee (2013,
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Normally, gas and liquid are collectively named fluids and their molecules can move freely so most of time the process of heat transfer is completed by the movement of molecules. When some molecules absorb heat energy, the density of this group of molecules decreases so they move upwards and other close cooler molecules fill the vacancy and this happens again to keep fluid molecules move in a circle. This phenomenon is called convection (Kreith, F et al. 2010). A common knowledge that hot air or hot water rises, can be explained. Applied to the thermal insulation of one house, it means that the house must be tightly sealed to prevent hot air from escaping outside and being replaced by cold air from outside in winter. Airtightness is not easy to achieve in construction. Because hot air rises, thermal insulation of the roof or ceiling is extremely important to prevent heat …show more content…
From perspectives of environment, insulation is the most cost effective way of reducing energy consumption and also can help to protect environment. As thermal insulation system maintains the temperature in rooms, it controls thermal energy loss or gain depending on different seasons; the demands of using air conditioners or fireplaces are reduced. In summer, citizens can hold patience to against sweltering hot weather without air conditioners, and in winter there is no need to burn wood or coal while a thick coat can solve all problems. As a result, the greenhouse gases emission is reduced as the amount of fuel burnt to produce electricity keeps falling. Furthermore, insulation reduces average home heating and cooling costs so the burden of increasing energy can be afforded. As the right insulation is a once-only cost that lasts for the life of the building and requires no further
An Investigation Into How the Thickness of Insulation Affects the Time a Drink Takes to Cool Down
Heat is lost through the atmosphere because of combustion. a process where a substance and oxygen or other elements combine to produce heat and light (fire). Combustion of alcohol produces water. and carbon dioxide. Therefore the amount of heat which is not being used to heat the water lost through the air.
... the sun isn’t as high up in the sky. Large open spaces and a covered loft promote stack ventilation which also further increase the comfort zone. A mud room/hallway doubles as an airlock during extreme temperature months. The addition of active systems suffices for the rest of the heating load. On the roof positioned is a solar hot water panel which has access to solar gain. A small tankless electric water heater boosts stored hot water temperatures when needed. The ultimate goal is to simply reduce energy use by half of what the average household uses. The equipment chosen is an Eemax Electric Tankless Hot Water Heater. A solar hot water panel mounted on the dormer heats water through glycol exchange. A tankless electric hot water heater 1) boosts the solarheated stored water if it is below desired temps and 2) provides back up water heating during cloudy periods.
Studies have shown that big changes in temperature do not affect the capability of insulation. In one experiment, materials were set to a high heat of 300 degrees Celsius. After six months in this environment, the substances were cooled to room temperature. The dielectric constant showing the level of insulation had not changed ("Teflon PTFE fluoropolymer resin" 28).
Another type of window that is used commonly to keep the home cool is tinted glass. Tinted glass and tinted window films are used on buildings to reduce heat gain through windows. Advancements in tinted glass have now allowed us to make the glass appear just as a regular window that you can see through. The tinted glass solution is also used in many vehicles and private rooms for privacy and to keep them cool in the summer to save on energy costs.
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 ...
Conduction can be seen when the ice touched the cans full of insulation. The cooled cans touched the installation inside the can making it cooler. Convection can be found al over the place in our experiments. When we heated our model dwelling with the heat lamp the outside of the house heated. This in turn heated the air inside making the air temperature rise.
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...
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.
Despite the fact that novel technologies are continuously under development to complement existing practices in coming up with greener buildings, the universal intent is that such structures are designed to diminish the general effect on the built environment on health of the humans in addition to the natural environment via: Diminishing environmental degradation, pollution and waste, improving productivity of the employee and guarding occupant health, efficient usage of water, energy, in addition to other resources.
Heat energy is transferred through three ways- conduction, convection and radiation. All three are able to transfer heat from one place to another based off of different principles however, are all three are connected by the physics of heat. Let’s start with heat- what exactly is heat? We can understand heat by knowing that “heat is a thermal energy that flows from the warmer areas to the cooler areas, and the thermal energy is the total of all kinetic energies within a given system.” (Soffar, 2015) Now, we can explore the means to which heat is transferred and how each of them occurs. Heat is transferred through conduction at the molecular level and in simple terms, the transfers occurs through physical contact. In conduction, “the substance
Well-recognized cities worldwide have built over the years great buildings with a variety of designs and concepts however consequently too much building has been making grievous decrease on energy efficiency. Now, “Green Architecture” has been popularized and as a result a modicum of energy efficiency has increased and also it has substantiated a new perspective, a new versatile way on architecture.
Research on fuel poverty and the health impacts of affordable warmth initiatives have to date primarily been conducted using quantitative and statistical methods, limiting the way how fuel poverty is understood. (Grey et al, 2017). The study found that insulating existing houses led to a significantly warmer, drier indoor environment and resulted in improved self-rated health, self-reported wheezing, days off school and work, and self-reported visits to general practitioners as well as a non-significant trend for fewer hospital admissions for respiratory conditions. Insulation was associated with a small increase in bedroom temperatures during the winter (0.5 °C) and decreased relative humidity (−2.3%), despite energy consumption in insulated houses being 81% of that in uninsulated houses” (i.e. a 19% reduction). The in-home temperatures increased in both the child's bedroom (0.57 °C) and the living room (1.10 °C), despite a small, but insignificant drop in overall energy consumption.
Household energy conservation is a very practical and realistic approach to conserving energy within our society. US households consume a tremendous amount of natural gas as well as electric energy. It has been calculated that the amount of energy consumed within the US increased exponentially from about 1850 to 1975. If energy continued to increase at this rate, we would be experiencing severe energy shortages in our current society. Luckily, steps towards conservation, including various energy regulations, have curbed that growth somewhat, brining the predicted 160 Qbtu/yr for the year 2000 down to around 93.8 Qbtu/yr by the year 1996. However, household energy usage is still a major issue as households consume about 38% of the total consumed energy and contribute greatly to natural gas consumption and issues such as global warming. Therefore, it is important that people understand how we use energy in the household and what steps can be taken to conserve that energy.
Life changed immensely in the 20th century as air conditioning and refrigeration systems became more efficient and controllable. Air Conditioning and Refrigeration play important roles in providing human comfort, food processing, storage, and many other industrial processes. We chose this topic because our life would be difficult without AC and Refrigeration. This paper will talk about the history of air conditioning and refrigeration, the role of engineers in designing and building it, people’s life before and after air conditioning and refrigeration, and finally Applications in the area of achievements and future developments.