seminar code
07-08-2014, 11:36 AM
Requirement of Air Conditioning
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INTRODUCTION
Air conditioning and refrigeration are provided through the removal of heat. Heat can be removed through radiation, convection, and by heat pump systems through a process called the refrigeration cycle.
Refrigeration conduction media such as water, air, ice, and chemicals are referred to as refrigerants. An air conditioning system, or a standalone air conditioner, provides cooling, ventilation, and humidity, control for all or part of a house or building.
The refrigeration cycle uses four essential elements to create a cooling effect. The system refrigerant starts its cycle in a gaseous state. The compressor pumps the refrigerant gas up to a high pressure and temperature. From there it enters a heat exchanger (sometimes called a "condensing coil" or condenser) where it loses energy (heat) to the outside. In the process the refrigerant condenses into a liquid. The liquid refrigerant is returned indoors to another heat exchanger ("evaporating coil" or evaporator). A metering device allows the liquid to flow in at a low pressure at the proper rate. As the liquid refrigerant evaporates it absorbs energy (heat) from the inside air, returns to the compressor, and repeats the cycle. In the process heat is absorbed from indoors and transferred outdoors, resulting in cooling of the building.
In variable climates, the system may include a reversing valve that automatically switches from heating in winter to cooling in summer. By reversing the flow of refrigerant, the heat pump refrigeration cycle is changed from cooling to heating or vice versa. This allows a residence or facility to be heated and cooled by a single piece of equipment, by the same means, and with the same hardware. Central, 'all-air' air conditioning systems (or package systems) with a combined outdoor condenser/evaporator unit are often installed in modern residences, offices, and public buildings, but are difficult to retrofit (install in a building that was not designed to receive it) because of the bulky air ducts required to carry the needed air to heat or cool an area.
Importance of A/C in Human Life
The most common, and arguably most important, use for refrigeration is food preservation. It used to be that people had to go to a market every day and buy fresh groceries before they perished. Early methods of food preservation such as cold cellars and salting were expensive, difficult to regulate, and didn’t maintain the same quality as what we are used to today. After the discovery of bacteria the importance of refrigeration became clear. Low temperatures slow chemical and biological processes including bacterial growth which spoils food. Modern refrigeration provides an environment too cold for harmful bacteria to flourish, keeping people healthy.
With contemporary refrigeration units I can buy lunch meat on Sunday and have it last all week long. A reliable method for keeping foods cold means I have to shop less frequently. It also allows for foods to be frozen and eaten out of season. Even if I ran out of my frozen fruits and vegetables, I could also buy out-of-season edibles from a place where they are in-season. Foods can be refrigerated and transported across the country and across the world. This means that I can now have a more diverse diet than what is grown in my area. Current refrigeration technology has changed our diets and lifestyles to be more diverse and healthy.
Refrigeration, especially at very low temperatures, has had an incredible impact on the medical world as well. Human tissue deteriorates quickly when it is not supported by a body. Organ transplants have had a much higher success rate since we started cooling the transported organs. Sperm and egg donation wouldn’t be possible without a way to preserve the cells. My dad is a doctor, and works at a sperm bank. Without refrigeration he wouldn’t have a job and there would be many potential parents without children. Many modern technologies rely on the ability to cool products.
ENERGY CONSERVATION
Definition of Energy Conservation:
Energy conservation refers to reducing energy through using less of an energy service. Energy conservation differs from efficient energy use, which refers to using less energy for a constant service. For example, driving less is an example of energy conservation. Driving the same amount with a higher mileage vehicle is an example of energy efficiency. Energy conservation and efficiency are both energy reduction techniques.
Increasing energy costs, inadequate electricity generation and distribution infrastructure and increasing demand for refrigeration and air-conditioning (RAC) are the problems faced by the users of refrigeration and air-conditioning systems. Effects of these problems can be reduced, by the HVACR community by implementing energy conservation measures in RAC.
GREEN BUILDING
Definition of Green Building:
There are many definitions of what a green building is or does. Definitions may range from a building that is “not as bad” as the average building in terms of its impact on the environment or one that is “notably better” than the average building, to one that may even represent a regenerative process where there is actually an improvement and restoration of the site and it’s surrounding environment. The ideal “green” project preserves and restores habitat that is vital for sustaining life and becomes a net producer and exporter of resources, materials, energy and water rather than being a net consumer. A green building is one whose construction and lifetime of operation assure the healthiest possible environment while representing the most efficient and least disruptive use of land, water, energy and resources. The optimum design solution is one that effectively emulates all of the natural systems and conditions of the pre-developed site – after development is complete.
Energy efficiency
Green building has a great advantage of reducing both embodied and operating energy consumption. Studies proved that those buildings which are built with wood will have a lower embodied energy than buildings made of brick, steel or other materials. What about operating energy? Designers try to find solutions to reduce it too. They use extra-insulation, high-performance windows, and passive solar design. The latter is very efficient especially if the windows are effectively placed. Also other ways of renewable energy are used too. Wind power and hydro power can also notably reduce the influence on environment.
Temperature Regulation
Urban heat islands are elevated temperatures mostly in urban areas, formed mostly on surfaces where permeable and moist became impermeable and dry due to some buildings, roads etc. Urban heat island effect is caused mostly by the heat holding properties of tall buildings and urban (often toxic) materials – asphalt, concrete. It can be compensated by more green areas around the buildings such as green roofs and rain gardens.
Indoor air quality
When constructing green buildings great emphases are put on the ventilation system. It can be powered in different ways – passively, naturally or mechanically. It doesn’t matter in which it is powered, the most important thing that a building should have a properly designed ventilation system in order to have a filtered andcleanerair. During construction low or zero emission materials are used. Most materials used for ordinary buildings are toxic, some of them radiate gases or include volatile organic compounds. It has a bad influence on occupant’s health and productivity. According to the data of the US Environmental Protection Agency indoor air pollution can be 2-5 times worse than outdoor air quality. It can cause early asthma and other respiratory disease. It is provoked by radon gas that’s found in conventional buildings. Another considerable feature of air quality is the control of dampness. If ventilation from bathrooms, kitchen and other isolated rooms is bad, it can lead to mold growth, dust mites or to the emergence of other bacteria. To avoid this problem effective ventilation system is not always enough; well-insulated building envelop is also needed
[attachment=66694]
INTRODUCTION
Air conditioning and refrigeration are provided through the removal of heat. Heat can be removed through radiation, convection, and by heat pump systems through a process called the refrigeration cycle.
Refrigeration conduction media such as water, air, ice, and chemicals are referred to as refrigerants. An air conditioning system, or a standalone air conditioner, provides cooling, ventilation, and humidity, control for all or part of a house or building.
The refrigeration cycle uses four essential elements to create a cooling effect. The system refrigerant starts its cycle in a gaseous state. The compressor pumps the refrigerant gas up to a high pressure and temperature. From there it enters a heat exchanger (sometimes called a "condensing coil" or condenser) where it loses energy (heat) to the outside. In the process the refrigerant condenses into a liquid. The liquid refrigerant is returned indoors to another heat exchanger ("evaporating coil" or evaporator). A metering device allows the liquid to flow in at a low pressure at the proper rate. As the liquid refrigerant evaporates it absorbs energy (heat) from the inside air, returns to the compressor, and repeats the cycle. In the process heat is absorbed from indoors and transferred outdoors, resulting in cooling of the building.
In variable climates, the system may include a reversing valve that automatically switches from heating in winter to cooling in summer. By reversing the flow of refrigerant, the heat pump refrigeration cycle is changed from cooling to heating or vice versa. This allows a residence or facility to be heated and cooled by a single piece of equipment, by the same means, and with the same hardware. Central, 'all-air' air conditioning systems (or package systems) with a combined outdoor condenser/evaporator unit are often installed in modern residences, offices, and public buildings, but are difficult to retrofit (install in a building that was not designed to receive it) because of the bulky air ducts required to carry the needed air to heat or cool an area.
Importance of A/C in Human Life
The most common, and arguably most important, use for refrigeration is food preservation. It used to be that people had to go to a market every day and buy fresh groceries before they perished. Early methods of food preservation such as cold cellars and salting were expensive, difficult to regulate, and didn’t maintain the same quality as what we are used to today. After the discovery of bacteria the importance of refrigeration became clear. Low temperatures slow chemical and biological processes including bacterial growth which spoils food. Modern refrigeration provides an environment too cold for harmful bacteria to flourish, keeping people healthy.
With contemporary refrigeration units I can buy lunch meat on Sunday and have it last all week long. A reliable method for keeping foods cold means I have to shop less frequently. It also allows for foods to be frozen and eaten out of season. Even if I ran out of my frozen fruits and vegetables, I could also buy out-of-season edibles from a place where they are in-season. Foods can be refrigerated and transported across the country and across the world. This means that I can now have a more diverse diet than what is grown in my area. Current refrigeration technology has changed our diets and lifestyles to be more diverse and healthy.
Refrigeration, especially at very low temperatures, has had an incredible impact on the medical world as well. Human tissue deteriorates quickly when it is not supported by a body. Organ transplants have had a much higher success rate since we started cooling the transported organs. Sperm and egg donation wouldn’t be possible without a way to preserve the cells. My dad is a doctor, and works at a sperm bank. Without refrigeration he wouldn’t have a job and there would be many potential parents without children. Many modern technologies rely on the ability to cool products.
ENERGY CONSERVATION
Definition of Energy Conservation:
Energy conservation refers to reducing energy through using less of an energy service. Energy conservation differs from efficient energy use, which refers to using less energy for a constant service. For example, driving less is an example of energy conservation. Driving the same amount with a higher mileage vehicle is an example of energy efficiency. Energy conservation and efficiency are both energy reduction techniques.
Increasing energy costs, inadequate electricity generation and distribution infrastructure and increasing demand for refrigeration and air-conditioning (RAC) are the problems faced by the users of refrigeration and air-conditioning systems. Effects of these problems can be reduced, by the HVACR community by implementing energy conservation measures in RAC.
GREEN BUILDING
Definition of Green Building:
There are many definitions of what a green building is or does. Definitions may range from a building that is “not as bad” as the average building in terms of its impact on the environment or one that is “notably better” than the average building, to one that may even represent a regenerative process where there is actually an improvement and restoration of the site and it’s surrounding environment. The ideal “green” project preserves and restores habitat that is vital for sustaining life and becomes a net producer and exporter of resources, materials, energy and water rather than being a net consumer. A green building is one whose construction and lifetime of operation assure the healthiest possible environment while representing the most efficient and least disruptive use of land, water, energy and resources. The optimum design solution is one that effectively emulates all of the natural systems and conditions of the pre-developed site – after development is complete.
Energy efficiency
Green building has a great advantage of reducing both embodied and operating energy consumption. Studies proved that those buildings which are built with wood will have a lower embodied energy than buildings made of brick, steel or other materials. What about operating energy? Designers try to find solutions to reduce it too. They use extra-insulation, high-performance windows, and passive solar design. The latter is very efficient especially if the windows are effectively placed. Also other ways of renewable energy are used too. Wind power and hydro power can also notably reduce the influence on environment.
Temperature Regulation
Urban heat islands are elevated temperatures mostly in urban areas, formed mostly on surfaces where permeable and moist became impermeable and dry due to some buildings, roads etc. Urban heat island effect is caused mostly by the heat holding properties of tall buildings and urban (often toxic) materials – asphalt, concrete. It can be compensated by more green areas around the buildings such as green roofs and rain gardens.
Indoor air quality
When constructing green buildings great emphases are put on the ventilation system. It can be powered in different ways – passively, naturally or mechanically. It doesn’t matter in which it is powered, the most important thing that a building should have a properly designed ventilation system in order to have a filtered andcleanerair. During construction low or zero emission materials are used. Most materials used for ordinary buildings are toxic, some of them radiate gases or include volatile organic compounds. It has a bad influence on occupant’s health and productivity. According to the data of the US Environmental Protection Agency indoor air pollution can be 2-5 times worse than outdoor air quality. It can cause early asthma and other respiratory disease. It is provoked by radon gas that’s found in conventional buildings. Another considerable feature of air quality is the control of dampness. If ventilation from bathrooms, kitchen and other isolated rooms is bad, it can lead to mold growth, dust mites or to the emergence of other bacteria. To avoid this problem effective ventilation system is not always enough; well-insulated building envelop is also needed