Welcome to my latest blog on all things to do with the environment, energy efficiency and technologies that can help you achieve savings in energy consumption and at the same time improve your carbon footprint. This is my initial set up of the page, with all comments, observations to follow soon. I have been involved in the industry for a few years now and hopefully you will find this blog both useful and informative. If you have any questions please feel free to email me at: generalcommentsplease@yahoo.com. Look forward to the following discussions that will inevitably follow on the environment, carbon footprinting and energy efficiency. Firstly, a discussion on how pollution from construction affects the environment.
Introduction
In terms of how the environment is effected by modern day construction techniques, pollution is quite a generic term. Covering subjects such as noise, fumes, demolition waste, Co2 emissions, etc. Perhaps the most lethal form of pollution today is the effect that Co2 production has on our environment. It is almost considered an undeniable fact that Co2 emissions is having a detrimental effect on the global atmosphere and is thought to be the most damaging gas to the environment.
The built environment
“The built environment is on of the most significant contributors to global warming” Builder (2007, p.18)
Not only does the energy used to extract, transport and build our environment contribute significantly to carbon emissions but so too does the energy used to maintain a building, according to a press release Eurima (2007, p.1) it is stated that as much as 40% of Europes Co2 emissions is as a direct result of energy used to maintain a building. To understand how this is so, one has to simply look at the services that a modern day building requires from day to day.
· Heating
The use of heating is a requirement in all buildings and how this is achieved will determine the efficiency of a building. Many large older office buildings will use a perimeter wet heating system, this needs to be heated via gas or oil fired burners.
· Lighting
Offices use a large amount of lighting, and, depending on the type of work that is conducted in offices will also determine the level of lighting required.
· Cooling
Cooling. It is becoming common place now to see offices with air conditioning or comfort cooling.
· Ventilation
Ventilation is often required in the workplace. Traditionally this is achieved through mechanical ventilation – requiring the use of additional electrical consumption.
· Refreshment facilities
Refreshment facilities for the use of hot drinks and food.
· ICT equipment
The energy required for PC use, printers, scanners, fax machines etc all a necesity in todays work place
· Sanitation
The use of water for washing and the flushing of toilets and urinals. It may seem odd to include water here, but it must be remembered to move water to a building requires energy
· Back up power services
The provision of generators to provide a continued electrical service in the event of power failure.
Some simple steps can be taken to reduce the amount of energy that the above processes use, are as follows:
· Lighting.
In new builds the most suitable solution is to maximise the use of natural daylight. Obviously the use of windows is considerd from the outset, but poor design can often lead to problems for occupants as well as the issue of maintenance. Often types of structure will not allow the use of windows, so artificial lighting is used, which, intialy is cheap and convenient. This can be overcome by the introduction of rooflights, which either channel natural daylight directly into a room or indirectly via refection. If artificial lighting must be used or alterations to a building is not possible, intelligent lighting controls should be retrofited and the use of high efficiency fluorescent lights should be considered. Intelligent lighting systems, through the use of photocells and proximity detectors can adjust lighiting levels (dimming if natural daylight is high) and switch off units during periods of non occupancy. This can result in high savings of electricity. The use of halogen spotlights are often seen in buildings, mainly for aesthetic reasons, to give an air of proffesionalism. Halogen spotlights are extremely inefficient and with the market saturation of LED’s (Light Emitting Diode) it is now affordable to replace a 25 Watt Halogen spotlight with a 3 Watt LED, the savings are evident.
· Cooling/Ventilation
For new buildings, cooling should be designed into the structure. A common (and cheap) approach is to ahieve a stack affect. A stack affect system utlises the difference in temprature and humidity to force air into a building and subsequently have a cooling affect by removing stale, hot air. Automated vents strategically placed within the building are operated by a building management system, opening and closing louvres as necessary to facilitate the effect. There are numerous other systems that can be used in addition to this, such as cooling the entire building fabric during hours of non occupancy by pumping chilled water through structural columns and beams, as well as having louvres open to allow the cooler night air into the building. By cooling the entire fabric if a building has a similar, reverse effect of a night storage heater. This system is not entirely green but does reduce the reliance on split air conditioning systems for example. Modern architectural designs are becoming increasingly bold in designing buildings geared towards efficiency. Tall structures especially create their only microclimate and designs taking this into account can use this effect and the phenomenon of the bernouli principle to produce forced ventilation for free cooling.
· Refreshment Facilities
To boil a kettle can use anything between 40 Watts and 150 Watts. This may not seem a great deal, but if this is considereed accumalatively then the consumption soon adds up. For example, a typical office building of 400 employees, may contain anything upto 40 kettles. So to do a simple calculation and using the lowest consumption figure the enery usage in one year may be as follows:
40 Watts * 6 boils a day * 40 Kettles * 7 (1 week) * 50 Weeks = 3,360,000 Watts or 3360Kwh per year. This is the equivalent to nearly 1 ½ Tonnes of Co2 per year. An alternative to this would be to install point of use hot water dispensers which have a far lower consumption. E.g. 800W per 24hrs * 4 dispensers * 351 days = ½ Tonne of Co2.
These are rough calculations and obviously there would be a cost implication, to work out the payback period and so on, but it does highlite how simple procedures can have significant impacts. Just this alone would prevent 1000 Kg of carbon emissions.
· ICT Equipment.
Similar calculations can be carried out to work our carbon savings for reducing the amount of printers used, moving to a centralised point of use for printing, faxing, scanning etc. Changing PC’s with energy hungry monitors to more efficient Flat screens.
· Sanitation.
Water savings are often disregarded which is probably due to an apprent abundant supply and also the general low cost. It should be noted, however that 97% of water on earth is seawater of which 2.7% of this is permanently frozen in the ice poles, leaving only 0.3% of fresh water according to Builder (2007, p.41)
A solution to reducing the use of water and consequntially reducing the electrical energy required to distribute water, rainwater harvesting is a feasible option. Recycling rain (grey) water is achieved through collecting the run off from rooftops and storing in an undeground tank. This can then be connected to the existing water system of a building and used alongside. The greywater can be used for flushing urinals and toilets. In a domestic sceneario water used from baths/showers or washing up of cutlery can also be utilsed, although this requires the additional use of a filtration system so it can then be reused. Rainwater harvesting systems can be retro fitted but work out far more cheaper if installed during a new build.
Some of the above procedures explained are relatively straight forward to implement and cheap, whilst others rely on installation at design stage, the intention is to identify how pollution of carbon can be reduced. To expand on this further microgeneration is explored.
Microgeneration
According to central government “microgeneration is the production of heat and/or electrcity on a small scale........from a low carbon source” Dti (sl).
Essentially microgeneration allows the user to provide their own electricity from sources that are either carbon neutral or have a very low carbon emission.
The following list is a number of technologies available and how they can be used to prevent carbon emissions.
· Solar photovoltaics
· Wind turbines
· Solar Thermal Hot Water
· Ground Source Heat Pumps
· Bio-Energy (Biomass)
· Fuel Cells
· Solar Photovoltaics
Solar photovoltaics has been established for decades now and has always been a very expensive form of producing free electric, although with improved technologies it is slowly showing signs of becoming more affordable. Solar Pholtaics or PV cells work buy a chemical reaction from sunlight acting upon silicon within the cell. The reaction produces electricity. This form of technology is used in many application from calculators and satelites to flat roof applications and glass curtain walling. It is completely free from carbon emissions and has a long shelf life. The main draw back with PV cells is that it is essentially weather dependant, this therefore requires electricity to be stored, for use on cloudy days for example. The produced electricity is stored in the form of batteries, similar to car batteries and can take up a lot of room and requires a maintenace regime by specialist contractors.
· Wind Turbines
Small scale turbines, as the name suggests rely on wind power to rotate the turbines and generate electricity. Very similar to how a traditional dynamo on bycicles is used, to power a light by using the turning wheel to rotate the dynamo, except in this instance it is wind turning the blades. This form of energy production is completely renewable and cheper than PV installations with shorter payback periods, although still expensive. Unfortunately this technology does not operate at 100% efficiency and is reliant on the environment, varing wind speeds will determine how much electricity can be produced. So this system will always require the use of other electrical sources during windless days, although it can be argued that
excess energy produced could also be stored in battery vats. No doubt that this would escalate the supply and installation cost significantly and deter potential clients.
· Solar Thermal Hot Water.
This system is perhaps the most easiest technology to install and also a lot cheper than other technologies. The principle is basic, with solar panels being fitted to a roof that collects heat from the suns radiation, this in turn is then used to heat water. This system is prolific in sunnier climates and despite the fluctuating weather in the UK the system is effective in the summer and also enough heat is generated in cooler months to produce approximateley 50% of heating requirements.
· Ground Source Heat Pumps
This technology often reffered to as geothermal energy uses the earth as a cooling and heating medium. At present there are a number of designs that are utilised, these are, horizontal loop system, vertical loop system and coil loop sytem. All of these achieve the same result of using the earth to extract the hot or cold energy from a refrigerant. The actual pump itself, as well as projecting the solution around the pipework boosts the cooling or heating capacity of the system. No doubt this is a very effective system and costs can be reasonable for basic installations. It must be noted that this sytem is not entireley a green technology, requiring the electrical energy for the heat pump, however claims of 3Kw of heating/Cooling for every 1Kw consumed. It should be noted however that the heat provided by geothermal energy is low grade, in other words it would not be suitable to replace an existing perimeter wet heating system but more to use it to reduce the heating requirement of existing plant, the tecvhnology is ideally suited to under floor heating, providing a permanent low grade heat output to the floor fabric.
· Biomass
Biomass is simply the production of crops for the use of burning in a purpose designed boiler or for the production of biofuel. This system is perhaps one of the cheapest available and easiest to use once installation of the required plant has taken place. It is effective and sourcing of the correct type of crop is becoming a lot easier due to continued press exposure with more farmers now becoming involved with the planting of the specialist crop. The major downfall of this technology is that the energy used in plant for farming and distribution of the fuel totally offsets the benefits it can be argued.
· Fuel Cells.
This is perhaps the most technically complex technology available on the market, originally developed by Nasa for use in shuttle expeditions, fuel cells are quite remarkable. A fuel cell will convert hydrogen into electricity with the only bi-product being water. There are an array of different types of fuel cells, but essentially they all achieve the same result. Again, as with other microgeneration the advances in science have enabled fuel cells to become affordable and products are just starting to emerge in the market. UPS systems announced its first fuel cell UPS order in July of this year. At the moment UPS (Uninteruptable Power Supply) is a very suitable use for fuel cells. Traditionally a UPS system is backed up by a fossil fuel burning generator to maintian electrical services during a power failure. Fuel cells can now replace the generator using hydrogen as a fuel source. The systems take up less space, are extremely quiet in operation and only produce water as a bi-product, which can easily be piped away from a building using a gravity feed. The price of hydrogen canisters are also begining to show favourable comparisons with fossil fuel. As with all systems there is a downside, which is production of Hydrogen. At present this is mainly achieved using electrcity generated from fossil fuel burning power plants. It is possible to extract Hydrogen from water and some experimental models are in the early design stage in an attempt to produce a fully renewable system.
“The activities of constructing and running a building have a major effect on the environment………….energy used in buildings is responsible for around half of the total production of carbon Dioxide gas” McMullan (2002, p.353)
Conclusion
It is without doubt that global warming is now given the attention and consideration that is required in an effort to make change happen and effectively prevent global warming from escalating to an irreversible level and protecting our environment. It is also widely accepted that air pollution through the manmade production of carbon emissions is a catalyst of global warming and the reduction of which will reduce the threat of climate change.
Central government appears to be stepping up its approach to climate change through various legislation, which has become a requirement since joining of the Kyoto protocol in 1997; requiring the UK to reduce its carbon dioxide emissions to 12.5% of 1990 levels by the year 2010, with a domestic target of 20% by 2010.
The climate change levy introduced in 2001 penalises companies for sourcing electricity from a non-renewable source, currently this is 0.43p per Kwh of power consumed, so by purchasing electricity from ‘green’ sources removes the levy. The building regulations have also recently gone through some changes. Part L of the regulations states that buildings must have a public display of the buildings energy rating – an effective way for companies to raise their profile by displaying an energy efficient poster showing a good rating. On a practical level new buildings must achieve a certain rating through increased energy performaning materials, plant etc before it can actually be built.
The role of central government is paramount in helping to reduce Co2 emissions. Through legislation and grants, newer, more efficient technologies can be harnessed. Without doubt, reducing the energy that buildings use will have a significant impact on the environment and micro generation is the technology that will help to achieve this.
Ironic then that over the decades, humanities drive for new technology e.g. the internal combustion engine, has in essence caused the problem of climate change, so it seems technology will solve the problem.
References
McMullan. R., (2002.) Environmental Science in Building. 5th ed. Hampshire: Palgrave
Department of Trade and Industry Fact Sheet., – Sources of energy file27590. [Online] Available at: <http://www.dti.gov.uk/files/file25790.pdf>
Builder and Engineer. C132, 06.07, p.18
Builder and Engineer. C132, 06.07, p.41
Eurima. S1, 12.06.07, p.1
I hope you have found this first post interesting. there will be more to follow soon on how you can achieve energy efficiency and how this affects the environment
