Building Performance - Assignment Example

Building Performance The structure selected was Greenwich millennium village. The Waste management and recycling: As it was d in case study of the construction, it was concentrated on innovative solutions and environment principles. It is for the sustainability, which is a result of organic incremental approach for housing construction. The important point observed in the case study was the recycling of 30 to 40 percent of the construction waste. Evaluation of the above point about recycling of the construction material: This involves the reduction of waste in construction process. This is capable of reducing the construction costs as the recycled material can be used in other constructions. If the recycling was done by other firm, the builder can sell the construction waste and can get monetary benefits which can compensate for the costs of construction. If the builder is big enough and is having own recycling process unit, he can use the recycled material in other constructions and can save investment on the constructions, which again reduces the construction costs. Regarding this positive evaluation, we must limit ourselves to reducing the construction costs only. This is because this is not the point to consider about the pollution involved in the recycling process and it will be considered separately. Evaluation of waste management and recycling of Construction waste: In the modern constructions the construction waste management at the site was considered as important component to increase sustainability of the building. The demolition debris and construction waste were the components that should be managed or recycled.1 The inclusion of the management along with recycling is due to the fact that only 20 percent of the waste was being recycled and the remaining waste is managed in the processes like land filling. The waste disposal causes an array of adverse effects. They are not felt by the people who are in building profession. They are now aware of the loss of the property, the materials wasted, embodied energy and the green house generation. All these things cause the environmental stressors, which are associated with giving rise to new materials. This stops usage of existing material. At present due to the decrease of land fills for the construction and demolition waste, the expenditure of the waste management was being increased. The higher distances that are to be travelled for hauling are increasing the fuel cost for the transportation. The fact that only 20 percent was being recycled, poses an opportunity of larger potential for the development in this sector. The recycling will ensure the availability of the resources for the future use. William McDonough considers waste as food in his book cradle to cradle. He tells this from the fact that the waste generated in the construction is the food for the industry (raw material). This usage of waste as food depends on technology available for the industry in using the waste as raw material. The important factor that can be considered before the management or the recycling of the waste is reusing. The waste from the demolition can be used on site or on the site else where. The wood materials can be used easily without any need of extra technology for the making of wooden articles required for the new construction. The gravel and aggregate products can be used in mixing concrete, but not all the gravel that is recovered from the debris. The gravel that contains minimum impurities can be used and the remaining can be sent for land filling or recycling plants. A part of the concrete that is obtained from the demolition can be used in filling the land and it finds very less usage in the construction site from where it was obtained. This can be sent for recycling or land filling. It will not find much use in the immediate construction. The bricks, stones and other masonry material, which is part of the demolition debris, can be used in the immediate construction if they are in good condition. For this purpose, care should be taken while in the demolition that it can be done without much spoiling of the bricks and wood. The ferrous and non ferrous metals find much use in recycling. These materials instead of reusing can be sent for recycling. This is because 75 percent of the demolition material that is recycled consists of ferrous and non ferrous metals. The plastic materials that are found in the demolition debris can be sent for the recycling process instead of reusing. These materials also form a large part of the material used for recycling form the demolition waste. The insulation material that is found in the demolition debris can be reused instead of recycling or land filling. This will reduce the construction cost and the transportation cost also. The reasons are that the insulation material is the substance that fills the gap between the walls and there is less chance for it to be spoiled in the demolition. So if it was retrieved carefully it can be reused resulting in the reduction of the construction costs. The un-tempered glass also can re used instead of recycling. The glass fittings can be removed without spoiling before demolition and can be used in the construction if needed and if the construction needs more sophisticated glass, they can be sold for the other constructions which need them. This brings in reduction of construction costs. The door and window assemblies also will find use in the reconstruction. They also can be reused instead of recycling. The alteration of these things require only carpentry work and need no extra technology, they can be used for the on going construction process. The fibrous acoustic materials can be sent for recycling, as they don't find much use in the immediate construction. These materials also form a substantial part of the materials that are recycled from demolition debris. The mechanical equipment can be reused or can be sold for minor constructions. It depends on the material used for the new construction. The lighting fixtures and electrical components can be sent for recycling as these materials also find enough use in the recycling process. The cardboard packing and packaging can be used for the same purpose if they are taken out before demolition without much damage. If not they can be sold as scrap resulting in the reduction costs. The planning of the waste management was considered as the part of the Greenwich millennium village project's development. The architectural and engineering services, the management consultant, contractors, and subcontractors were engaged in the waste management. But this involvement is due to the goals set by the owners and architects. The means, methods, techniques, sequences and procedures that are involved in the construction must contain the methods of waste disposal also. This project's design contributed the waste reduction in the following ways. Performing different functions with same material instead of using multiple materials causes optimization. This avoided the use of extraneous materials which increases the construction wastage. This was reflected in using less area and volume because the design caused less waste generation on the web site. The different methods involved in reducing cutting, special fitting and creating scrap involved in reducing the embodied energy and thus decrease of operational energy in the future. (The term embodied energy will be discussed in the later part of this paper.) The construction selected the systems that do require only minimum temporary support resulting in less debris during and after construction. Instead of using cement, the usage of cement tiles decreased the cement wastage on the construction site. The builders selected the materials that do not rely on adhesives. This system reduced the debris caused due to the empty containers. By selecting the material with integral finishing, the contractors reduced the usage of the materials that used for finishing, laminating and coating. The builder used the material that is not sensitive to damage, contamination and environmental exposure. This avoided the spoiling of the items on the site and reduced the waste. The minimum waste and debris diversion criteria were specified. This was included in the construction and demolition specification as criteria. The job site waste reduction was done by diverting the construction waste and demolition waste at the job site. By reducing the extra packing and packaging, the cardboard wastage was minimised. The builders purchased the materials in bulk, which reduced the packaging wastes. They used the containers which are reusable and even the packing materials used are retainable. This reduced the waste due to containers of the material. The usage of non returnable containers up to the maximum extent caused less waste. The builder used the direct sub contractors and trader who collect and keep scrap at cutting and fabricating works. The materials which are need a heat and mix, must be prepared according to the use by limiting their preparation. If they are wasted that environmental pollution and wastage caused by that is not reversible. The maximum number of damaged components is subjected to recycling. They arranged a return and buy back arrangements with the suppliers, which resulted in minimum wastage of the materials. There are contractors for taking the commingled debris and waste from the site. The builders engaged such a contractor and that reduced the piling of waste on site. The price that was spent on engaging a contractor for this purpose is not more than engaging a land fill process. Some times it was less also. The wood waste was sold as boiler fuel contractor engaged the individual recycling firms that deal in specific materials. This resulted in reusing or recycling of maximum material which is a part of C&D waste. Instead of dealing with a general waste hauler the contractor dealt with the individual recycling and reusing firms. This resulted in placing receptacles in the construction site, which enabled the work force on site to segregate material into the receptacles. In the absence of the receptacles, all the waste would have piled in a single space. The presence of receptacles of different substances made the segregation of the waste materials possible at the work place. The traders enter into the site and take their respective receptacles without much time spending on the site. This saves time for the contractors and the traders that deal with the waste material in construction. The segregation has another merit for its credit. The segregated material will give more price for the waste. The price of non segregated material is less than the segregated one. This further reduced the construction costs. The construction used a reasonable amount material, which was obtained for re use from a demolition. This again reduced the construction cost. The wood flooring, cabinetry, mechanical equipment are some of the list, which are obtained from a demolition site for the re using purposes. The uncertainty regarding the waste management, recycling and reusing is due to the non availability of the outlets that offer them. This makes the costs associated with these services exceed the costs when the construction was done without these management systems. But in case of Greenwich millennium village, the builder pre planned the waste management system and even arranged receptacles for the segregation of the waste and the traders who collect the segregated waste from the site. This made the cost of waste management to transform in to an income source which reduced the cost of construction. CO reduction : Due to reduction in the usage of conventional fuels for the generation of energy in the works like drawing water and for electrical appliances the CO2 emissions will decrease by approximately 5 to 6 percent in first year of operation. After that in the coming two years by adopting more modern technology and power saving appliances the CO2 can be reduced by 10 percent from the level that is 3 years back. The decrease of CO2 emissions is due to the usage of solar energy for the purposes of drawing of water and public lighting system. wall U value of about 0.2 W/M K The diagram below shows the temperature swing of the room. The temperature absorbed during the hot part of the day must go out during the colder part. The above diagram is adopted from http://www.energy.kth.se/courses/4A1622/TCIC2006-Assignment2.pdf For this purpose, the houses situated on the top floor middle floors and the down floors must have different wall U value. This will be a minimum of about 0.2 W/M K. The different values for the thickness of the walls and roofs and the substances used will be in such a manner to control radiation. The ventilation unit is given as optional to all the houses in the construction. By switching it on they can manage the temperature in the house as 25 degrees centigrade. If they want to save the power they can keep off the ventilation system. This was made possible by not making ventilation system individual instead of making it central. The decrease of the operational energy: The usage of renewable energy sources and the instruments resulted in the decrease of operational energy. 10 percent of the energy was saved operationally due to usage of solar heaters and wind mills. The public lighting system arranged in and around the construction will use solar panels and wind mills for the power that is needed for its working. This reduced the burden of power costs on the residents. This resulted in pollution free environment also. Though there is initial higher investment on solar panels it was made, keeping in mind the reduction of operational energy. In the construction itself the arrangements were made to decrease both embodied and operational energy. These arrangements are part of that planning which are supposed to decrease the operational energy. The above diagrams are adopted from http://oee.nrcan.gc.ca/publications/infosource/pub/ici/eii/m27-01-1350e.cfmattr=20 The usage of structural insulated panels, insulated concrete forms, aerated concrete blocks resulted in energy saving. These arrangements will save operational energy by avoiding over heating and over cooling. The moderate temperature maintained in the construction reduces the usage of A/C machines, coolers, fans and room heaters. This resulted in savings of the power resulting in saving of operational energy. The windows and doors were made with environmentally attractive material. This made possible the energy standard less stringent and cost effective. This resulted in recycled windows and less heated buildings. The energy consumers like electrical appliances were selected according to power save mode. The refrigerators, coolers, washing machines were selected in a manner to reduce power consumption. The modern appliances which have several electronic gadgets to work on power save modes are selected and installed. This resulted in decrease of the operational energy. The equipment that use renewable energy like sun and wind were arranged. The solar water heaters were arranged for the common use. The photo voltaic systems for the common lighting systems and wind turbines for the electricity that draws ground water were used. Fuel cells usage was avoided. The usage of fuel cells decreases the pollution and the operational energy. The pollution in the manufacturing of fuel cells results in increase of embodied energy and atmospheric pollution. Due to this reason the usage of fuel cells was avoided. The toilets and shower heads were selected to conserve the water. The good performance of them will result in water conservation. But this type of water conservation will be minimum and the arrangements like rain water conservation were made to make the water conservation maximum. Embodied energy: Embodied energy is the energy consumed by all the processes associated with the production of a building. These processes range form acquisition of natural resources to the product delivery. Mining, manufacturing materials, equipment and its transport also were included in the calculation of embodied energy. This is significant on life cycle impact of a construction. 1 Any construction is a complex combination of many materials. The materials in the building contribute to the embodied energy of the building. Even the renovation and the maintenance will add to the embodied energy of the construction. In the past it was thought that the embodied energy is small when compared with the operational energy. So the increase of embodied energy was not felt bad to decrease of operational energy. But recently it was discovered that the embodied energy of the construction is almost one tenth of the operational energy of the construction. If necessary precautions are not taken the embodied energy will be equal to 10 years of the operational energy of the building. The significant factor that plays a role in decreasing the effect of embodied energy is designing the building for long life and durability. When the building is designed for long life, the embodied energy will be less when compared to the operational energy. That is the same amount embodied energy will be used for longer life of a building, which causes less environmental pollution. The Life cycle assessment will assess the environmental adverse affects of the building. The depleting of resources, energy and water use, green house emissions and waste generation must be less to have less embodied energy. If there is no chance of decreasing the embodied energy the building must be designed for long life as the same depletion of resources will result in long life of the construction. The significance of embodied energy The materials chosen for the building reduced the embodied energy content. Instead of simply considering the low operational energy the steps were taken to have much less embodied energy. The operational energy depends on the residents of the construction. But embodied energy depends on the way and methods employed for the construction. So it was minimised by accurate planning. Previously the construction processes used to involve 1000 Giga Joules of energy, which can be considered as 15 years of operational energy. If the building life time is taken as 100 years this is almost one sixth part of it. But now a days the accurate planning and waste management and recycling the embodied energy was decreased to the 10 years of operational energy. The re usage of wood and insulation materials will further decrease the proportion of embodied energy when compared to operational energy. One factor that was used in the construction of Greenwich millennium village is the Thermal mass factor. Thermal mass is the capacity of a particular material to absorb the heat energy. The materials like concrete, bricks and tiles have high thermal mass and the timber and wood have low thermal mass. If the building is having a high thermal mass it will have cool day and warm nights. This is due to the fact that the heat takes time to enter in to the home and takes time to go out. By the time the heat enters into home, the night comes and it will be warm, and by the time it goes out it will be day and it will be cool. So to decrease the operational energy the materials such as bricks and concrete are preferred on every part of the construction. But to decrease the embodied energy along with operational energy, the walls are constructed with gaps and in those gaps the insulation material is filled. This reduces the usage of concrete and stones and decrease the embodied energy and decreases the operational energy also due to the insulation to the heat and cold. Picture adopted from: http://www.greenhouse.gov.au/yourhome/technical/fs17.htm High thermal mass is beneficial if there is remarkable difference between day and night temperatures. So the atmosphere in this area is suitable for the construction of high thermal mass constructions. The slab on the ground is constructed instead of a suspended slab because it had a greater thermal mass. This is due to the direct contact with the ground. The edges of the slab are insulated in the cold climates. The termite proofing was also done for the insulations of slab edges. the above picture is adopted from http://www.greenhouse.gov.au/yourhome/technical/fs17.htm The embodied energy is important due to the energy efficiency of the houses. The embodied energy is reduced if the energy efficiency is more. The energy used in transport the materials and workers to the site also was considered in calculating embodied energy. But the builders of Greenwich millennium village followed the waste management methods, so that the transportation of the materials and waste enabled the other constructions. So the embodied energy was decreased enabling them in decreasing in cost also. The materials used in the construction of building shell and the substances used in the construction of bathroom and kitchen fittings were selected to decrease the embodied energy. In these materials the recycled substances were used. This decreased the embodied energy. Care was taken by the builders to decrease both embodied and operational energy. Part 3 Comparison between Greenwich Millenium Village and the Solar low energy houses Before the comparison the following diagram will tell about the market penetration of a technology. This is because we are about to compare the low energy houses with that of Greenwich millennium village The above picture is adopted from www.ctg-net.com/Energetics/YourResources/gree The low energy buildings were built by using 25 percent energy used in most typical residential constructions today. But in the case of Greenwich Millenium village the energy was decreased by successfully using waste management and waste recycling. The low energy houses constructed were used far less energy than the Greenwich millennium village. In case of land fill, ozone depleting chemicals and even by reducing the purchased water they consumed far less energy than the Greenwich millennium village. But these low energy houses use the technology which is not cost effective. This type of technology was used in Greenwich millennium village only for common use systems like public lighting and water supply for the residents. They did not use the costly technology for the residences in the village. This is due to the fact of taking the cost effectiveness also into consideration. The Greenwich village consumes less energy due to usage of the the high cost solar technology for the common use, the energy consumption will not differ much from that of low energy houses. The energy consumption for the water heating in low energy houses is more in the case of low energy houses and it was reasonable in the case of Greenwich millennium village. Focussing on effects on the house in one season can affect the comforts in another season. The high thermal mass construction of Greenwich millennium village is suitable for the climate in all the seasons. But the low energy houses constructed will show their good effects only in winter season but not in all the seasons. In case of Greenwich millennium village both the tasks of using specific technologies and the technologies regarding the whole construction were used. But in the case of low energy houses only the technologies regarding the whole building were used. This effected the individual comforts of every house present in the building in the case of low energy houses. In case of Greenwich millennium village the high level insulation is preferred but not super windows. But in the case of low energy houses super windows were preferred to get the benefits of low E coatings and gas fillings. The mechanical ventilation systems were preferred in low energy houses, but in Greenwich millennium village, the system was optional. The individual houses can switch on or switch off the ventilation systems. This is not in the case of low energy houses as it was centralised. This can be considered as an advantage and a disadvantage. The mechanical ventilations system adjusts the ventilation of the house, but at the same time consumes more electricity. Passive solar gains cause space heating, but proper use of the technology will not cause it. But the proper use of the technology was not possible till now and the low energy houses cause space heating due to passive solar gains, which is not seen in Greenwich millennium village. But passive solar systems offer sun spaces in the dwellings, which are absent in Greenwich millennium village. But the amenities in the low energy houses were common type but the facilities in the Greenwich millennium village are individual residence oriented. In both the cases the effective way of reducing the water heating requirements were followed. IN the case of low energy houses, solar technology was used but in the case of Greenwich millennium village, both solar and wind mill technology used for water drawing and heating processes. This gives advantage for water heating in winter for Greenwich village as it depends not only on solar but also on wind mill technology. The solar space heating is technically feasible but not cost effective and was used in low energy houses. This increased the expenditure. These types of non feasible costs were not employed in the construction of the Greenwich millennium village. The complete dependence on photovoltaic was not cost effective. But this was followed in low energy houses. In the case of Greenwich millennium village wherever possible, the photovoltaic technology was used and option for the adoption of the technology in the future was given in the context where it was not used at present. This made the Greenwich both technologically feasible and cost effective. The lack of advanced calculation appears in the case of integrated design. The case of Greenwich village is not that type. They adopted the advanced technologies wherever possible and used present technologies leaving an option for the adoption of the advanced technologies in future. In the case of low energy houses the actual energy used or consumed exceeded the estimations. But in the case of Greenwich millennium village the energy estimations were done accurately and that resulted in accurate prediction of the energy consumption of the occupants. The training for the builders is necessary as it involves more technology and mechanical equipment in low energy houses. Even in the case of Greenwich millennium village also an accurate planning regarding the waste management, recycling which decreased both embodied energy and operational energy was followed. The technology used in the low energy houses is not cost effective and not commercially feasible. But the planning the technologies used in the Greenwich millennium village are feasible everywhere and easy to follow. The technology used in the low energy houses is in the experimental stage and the construction of low energy houses can be considered as an experiment. Whether it is a success or a failure, the construction can be considered as an experiment and the lapses can be corrected in the future. But that is not the case in Greenwich millennium village. Here the technology and the facilities were used in the manner that is feasible commercially. The prototypes used in the low energy houses can be considered as the laboratory testing of the techniques and the technology used. In the case of Greenwich millennium village the time tested technologies were used and the technologies were used in a limited manner. The Greenwich millennium village was a construction that is reflecting both the eco friendliness and the comforts. But the low energy houses were the ones which are the grounds of testing for the future energy saving houses. The low energy building have market in a number of countries. The experience in these construction can be used in constructing these type of houses in those countries. In case of Greenwich millennium village the type of technologies used and the way they plan the daily activities were extensively followed in all the countries, which are trying to build eco friendly houses. References: 1. Tom Napier, 2006, Construction waste management, Whole Building Design Guide, ,electronic, 30-11-06, http://www.wbdg.org/design/cwm.php 2. Technical manual, 2006, embodied energy, Your Home, ,electronic, 30-11-06, http://www.greenhouse.gov.au/yourhome/technical/fs31.htm 3. Anne Grete Hestnes, 1996, Final task management report, The royal ministry of industry, ,electronic, 30-11-06, http://www.iea-shc.org/outputs/task13/task13_advanced_solar_low_energy_buildings.pdf Read More