This essay has been submitted by a student. This is not an example of the work written by our professional essay writers.
Singapore has a few power stations which rely on external imports of fossil fuel to generate electricity. According to figure 1, electricity consumption is Singapore has been on the rise and this is a prevailing concern as our country's population is growing.
From figure 2, Singapore has the second largest increase in electrical tariffs since 2005
1.2 Measures HDB has implemented
To cope with the increasing demand, HDB has been constantly seeking find innovative ways to utilise energy efficiently.
HDB Greenprint and Eco-Town
HDB is looking into different ways to conserve energy like developing Punggol as the first eco-town in Singapore to test the new ideas and technologies. (http://app.mewr.gov.sg/web/Contents/Contents.aspx?ContId=1713) The aim is to develop and introduce effective planning and concepts for residents to adopt eco-lifestyles. It also aims to educate people to be part of 'go green' efforts. (HDB, 2010) Also, the HDB Greenprint, a framework of goal and strategies to guide greener HDB town development and create sustainable homes, that introduces the concept of green and sustainable lifestyles to other towns beyond Punggol. (MND, 2012). Solar panels and LED lightings will be implemented. The solar energy generated will be used to power lifts, lighting in common areas, and water pumps. (Alphonsus, 2012)
The criteria for the measures include:
Clean form of energy
The following table shows the three measures that we reviewed on
Benefits (include potential)
Figure 4: Solar panels installed on the roof of a HDB block (http://www.flickr.com/photos/37684278@N08/3469848211/in/photostream)
does not take up land space (Figure 3).
harnesses sun's energy, converting it to electrical energy.
Cost effective solutions to energy problems in places where there is no mains electricity
Need to be placed at sites where there is sunlight for electricity to be generated.
Placement of the solar panels is constrained within certain specific places.
Dependent on weather and sunlight is only available in the daylight.
Figure 5: Distribution of energy consumption of a HDB block (http://www.bri.sg/showcase/led-rd/)
Installation of LED lightings has significantly help Town Councils lower their energy bills -
Lightings altogether contribute to 50% of energy consumption in a HDB block (Figure 5)
High overhead costs -have to purchase LED in bulk thus making LEDs expensive
utilizes expensive sapphire-based technology which contributes to high costs of production
Figure 6: Water pumps
Have minimum bends and fittings to reduce head loss due to friction.
Optimizes the water system's performance and reduces energy cost.
Installed with sensors to activate pump when there is actual demand of water. (HDB, 2011)
No limitations - sized correctly for the block. (Lester Chia, email, 11 October 2012)
Figure 7 : Wind turbine
Converts kinetic energy from the wind into mechanical energy
Clean as it does not release greenhouse gases into the atmosphere
Does not consume fossil fuels
Singapore's weather conditions do not have strong wind patterns that the windmills need to acquire in order to generate power.
Set-up cost of building a windmill is costly hence not allowing for easy implementation
Figure 8 : Hydroelectric dam
Converts kinetic energy from moving water to chemical potential energy when stored in a battery which then translates into electricity.
Able to convert 90% of the available energy from electricity, more feasible than most efficient fossil fuel plants which are only 60% efficient.
Could not build dams near HDB flats as a result of not having a consistent large body of water
1.5 Analysis on the limitations of the measures that HDB can look into
Although both suggested measures produces clean energy, HDB is unable to build windmills as Singapore's weather conditions does not have strong wind patterns that the windmills need to acquire in order to generate power. Thus, it is not being able to generate enough power that is sufficient for use. Moreover, the set-up cost of building a windmill is costly hence not allowing for easy implementation by the relevant authorities and is not cost efficient. On the other hand, HDB may look into using the hydropower technology which Marina Barrage is currently benefitting from. However, since they could not build dams nearby HDB flats as a result of not having a consistent large body of water, the idea of building dams can hardly be implemented.
1.6 Inspiration: TOTO Faucet with a hydroelectric power generator
It occurred to us that the need of seeking sustainable energy resources is real; given the limited sources of energy supply we rely on, it will not be enough for our growing population. From figure 2, Singapore electrical tariffs are one of the highest in the world. Being small with limited space and supply of natural resources, Singapore is disadvantaged as it lacks multiple sustainable energy plants like windmills and hydroelectric dams. Since majority of the Singapore population stays in HDB flats and each flat has a few water tanks both on rooftop or ground floor, we would like to propose our idea that utilises hydropower technology using the water tanks as the water supply. From our survey (annex A), 96% of the respondents responded positively towards installing of this device in the faucet. Thus, we believe that we can expand the idea to a more large scale project, installing it at HDB instead.
2.1 Project Objectives
1. Â To ascertain the form of clean energy HDB can use to adapt to which is cost-efficient and allows for easy implementation
2. To come out with a detailed proposal for DAltMech
3. To work out the cost-benefit analysis of adapting the DAltMech technology
4. To review the proposal based on the interviews and survey gathered
Chapter 3 Product proposal (DAltMech)
3.1 Inspiration Leading Our Proposed Idea
Figure 7: TOTO's self-sustaining faucet (http://www.totousa.com/Green/Products/EcoPowerFaucets.aspx)
TOTO is the world's largest plumbing products manufacturer. They provide a complete line of commercial and decorative plumbing fixtures and fittings. (http://www.totousa.com/WhyTOTO/AboutTOTO.aspx). The technology that inspired us was the self-sustaining faucet technology, the TOTO EcoPower Technology. This technology works by harnessing energy from the water flowing through the tap to generate electricity (Figure 7) which is then stored in the rechargeable cells that power the Smart Sensor System (http://www.totousa.com/Green/Products/EcoPowerFaucets.aspx). Our idea uses the technology similar to TOTO EcoPower faucet that utilises the hydropower technology. Henceforth, adapting the mechanism of how EcoPower works but, in a different situation where a turbine wheel would be placed in the main pipes of the water tanks on the rooftop of HDB flats. (Figure 8)
3.2 How DAltMech works
Figure 8: Flowchart of how DAltMech works
Inspired by the TOTO EcoPower technology, we decided to adapt it and implement it for a much larger scale such as in HDB flats. Instead of implementing it at the tap, we decided to implement it at the pipe which connects our household water faucets to the main water tank on the rooftop of the flat (Figure 9). DAltMech adapts this technology which helps in harnessing energy using the water flow from the water tanks at the top of the HDB buildings. (Figure 8 & 9)
3.2.1 Location of DAltMech
Figure 9: Water tanks on top of HDB flats
Water flow in the water pipe connected to the water tanks (figure 9) occurs whenever there is water usage from any unit in the building. This water flow produced will then turn the turbine wheel, which will generate electrical energy. The electrical energy generated will then be transmitted across a wire connected to an external power storage, which can store the electrical energy over time (figure 8).
Figure 10: Layout of how the power grid is connected to the HDB flat
Hence, the power generated by the wheel in the water pipe at the rooftop (Figure 9) can be used to power the corridor lighting for the whole block (Figure 11). Thus the corridor lighting need not depend on the main electrical supply from the power grid (Figure 10).
Figure 11: How the power stored in the battery would be used for powering the corridor lightings
3.2.2 Placement of the wheel
Figure 12: Placement of the turbine wheel
Figure 13: Side view of wheel in the horizontal pipe
The more frequent usage of the water tanks on the rooftop would imply that the power generated by the wheel would be more as compared to implementing the wheel at the ground floor. The wheel would be placed in the horizontal pipe (figure 13) that is connected to the water tank (figure 12).
3.2.3 Size of the wheel
Figure 14: Cross-sectional area of wheel in pipe
This water pipe at the rooftop of a HDB flat (figure 12) has an internal radius of 20mm (figure 13). The internal radius of the pipe (figure 12) is 20mm (Lester Chia M.H, personal communication, 14 September, 2012). Thus the diameter of the wheel could be made at 36 mm (figure 14) so to avoid contact with the inner wall of the pipe, which will result in energy loss due to friction and wear and tear of the pipe.
3.2.4 Nozzle component
Figure 15: Location of the nozzle and wheel
Figure 16: Placement of nozzle and wheel components
Making use of the nozzle which jets water at the water buckets of the Pelton wheel (Figure 16), the nozzle will be placed in the component pipe right before the horizontal pipe (Figure 15). With reference to figure 17, the water flow from the nozzle will hit the runner with buckets which is the main component that converts the moving energy of the moving fluid into rotational energy that turns the turbine shaft. Since the nozzle targets water onto the wheel from the left side, this would result in the turbine turning clockwise. (Figure 17)
Figure 17: How the nozzle is angled tangentially to Pelton wheel
Figure 18: How the spinning of the Pelton turbine wheel generates energy (http://www.youtube.com/watch?v=2lrLtesjbtg&feature=youtu.be)
The spinning of the turbine would result in the simultaneous spinning of the Pelton shaft (Figure 18) which is connected to the generator as they are connected to each other. (Figure 17) Hence, this will produce power from the water flow that causes the wheel to spin. The power generated would then be stored in a battery for usage.
3.3 Materials used for DAltMech
Turbine and wheel
Figure 19: Pelton turbine wheel (http://www.microhydropower.com/our-products/pelton-wheel/)
We are using the Pelton Turbine wheel in DAltMech (figure 19). It consists of a wheel with a series of split buckets set around its rim; a high velocity jet of water is directed tangentially at the wheel (http://w3.tm.tue.nl/fileadmin/tm/TDO/Indonesie/Hydro_Power.pdf). This causes the water to leave the wheel at a lower speed, implying that most of the kinetic energy has been converted to electrical energy, leading to high efficiency of 90% (http://www.renewablesfirst.co.uk/pelton-and-turgo-turbines.html).
We decided to adapt these features for our wheel due to the high efficiency it creates. Furthermore, the Pelton wheel is able to be used for do-it-yourself application as it can have a diameter of 10cm (http://www.microhydropower.com/our-products/pelton-wheel/).
This shows that the wheel can be made small enough to fit into the pipe, thus making our project feasible.
Figure 20: LV750 by HI-POWER
The generator we are using is the LV750 by HI-POWER (Figure 20). It is HI-Power's latest and most efficient low-voltage brushless permanent magnet generator (http://www.nooutage.com/lv1400.htm). The space it occupies is 12 square inches, which means that it does not take up too much space and can be installed on HDB rooftops. It can generate a maximum power of 750W (http://www.homehydro.com/lv1500.html).
Figure 21: Durathon battery (http://geenergystorage.com/)
The battery we are using is the GE Durathon Battery (figure 21). It can store up to 577V of energy and deliver a power of up to 16.7 kW over 6 hours.
3.3.4 Cost of Materials
The table below shows the cost of each component and the total cost:
Cost of installation
Figure 22: Table of the respective cost of the components
3.4 Projected power generated
The projected power we have calculated is 528.3kWh. It is able to power up 65% of the power consumed by LED lights. Please refer to Annex B (Part 1) for the detailed calculations of the projected power generated.
3.5 How DAltMech addresses the needs of HDB
The LED lights in HDB consume a total of 800kWh of power per month (Lester Chia M.H, personal communication, 14 September, 2012). Given the power generated by our wheel in one month is 523.8 kWh, it can be used to power up 65% of the power consumed by LED lights. Thus it can help HDB to save 65% of the electrical bills.
Chapter 4 Review of DAltMech
4.1 Location of the DAltMech turbine wheel
Figure 23: Water supply to various floors of a 12-storey block
After an interview with HDB engineer Mr Lester Chia, he gave us a general layout of the HDB building and its components (figure 24). A usual 12-storey HDB building will have a water pump located at the ground floor (Figure 23) This pump would provide water for households in the first four storey. (Lester Chia M.H, personal communication, 14 September, 2012) Through this interview, we realised that there is another pipe in which we can place the turbine wheel. He mentioned that this pipe has a larger internal radius of 50 mm whereas at the pipe at the main water tank on top of the building has an internal radius of 20 mm. This bigger pipe is located at the ground floor while the small pipe is located near the water tank.
With these two pieces of information, we could place the turbine wheel at the pipe which water is just pumped from ground level to the water tank. Thus we hypothesize a larger internal radius will give a larger water flow rate, which in turn will generate a larger amount of electricity (http://www.articlesbase.com/environment-articles/hydro-energy-using-the-power-of-water-for-your-electrical-needs-5957734.html)
Figure 24: Layout of HDB buildings and its components
However, the amount of electricity generated is based on how fast the turbine wheel can turn which in turn is dependent on the speed of water flow (http://www.articlesbase.com/environment-articles/hydro-energy-using-the-power-of-water-for-your-electrical-needs-5957734.html).
The downside of this is that by installing the wheel in the pipe which water is just pumped from ground level to the water tank, it will lead to a reduced water velocity as proven by the Equation of Continuity.
Through our calculations, we found out that it is more worthwhile to install the wheel in the water pipe from water tanks as it is able generate more power.
Please refer to Annex B (part 2) for detailed calculations.
4.2 Position of DAltMech turbine wheel
Figure 25: Location of the wheel
Figure 26: Vertical placement of the wheel
The Pelton wheel is placed vertically in the pipe, with the buckets facing the water flow to prevent any obstruction to the water flow (figure 26). If the wheel is placed horizontally, the water would just be hitting against the wheel and the wheel will not turn as efficiently, leading to lower power output (figure 27). A nozzle is used to direct the water flow to the buckets. When water comes in contact with the buckets, pressure is exerted, turning the turbine. It is placed at the horizontal pipe (figure 25) instead of the vertical one as there will be jerks that obstruct the turning of the turbine when it comes in contact with water. This renders the project to be less efficient.
Figure 27: Energy efficiency of DAltMech
Figure 27 shows the efficiency of each components of DAltMech. As electricity flows through the turbine, generator and wheel, some energy will be loss to the surrounding. After some calculations (refer to Annex B part 3), we realised that the final energy stored in the battery is about 442.04 kW. This amount can help supply about 55% of the energy that LED lightings require. Thus, this renders our idea efficient as we are able to help lessen the amount of energy that we rely on from the mains.
4.4 Improvements to DAltMech
Another type of wheel that we can consider is the Turgo wheel (Figure 28).
Figure 28: Turgo turbine wheel
The table below shows the comparison between Pelton and Turgo wheel (figure 29).
Water strikes the blades at 180 degrees
Water strikes the blades at 20 degrees
Costs $95 (http://h-hydro.com/)
Figure 29: Table showing comparisons between Pelton and Turgo wheel
From the table, both wheels are 90% efficient, which means that there will be no difference in power loss if either wheel is used. For the Pelton wheel, water strikes the blades at 180 degrees, which results in the discharged fluid interfering with the incoming water flow (http://w3.tm.tue.nl/fileadmin/tm/TDO/Indonesie/Hydro_Power.pdf).
For the Turgo wheel, water strikes the blades at 20 degrees. This enables the water to turn the wheel and exit immediately without any interference. Thus, the Turgo wheel can have a smaller diameter than the Pelton wheel for the same amount of power to be generated. This will lead to a lower cost of wheel and installation. Lower cost is particularly important as if DAltMech were to be implemented for all HDB flats as a lot of savings will be reaped off. This fulfills one of the criteria that we had established: cost-efficient technology.
4.5 Cost-benefit analysis
The power generated by DAltMech is able to compensate for more than half of the power consumed by HDB LED lights. Since it is able to cover both the cost of implementation and compensate for more than half of the power consumed by HDB LED lights, it should therefore be implemented. (Please refer to Annex B, part 4 for a detailed cost-benefit analysis)
Through this innovation, it will help Singapore to gain international recognition as an innovation hub of promoting greener environments. It could also raise the awareness among Singaporeans on the issue of rising electrical tariffs and what is being done to conserve fossil fuels. HDB buildings will then be indirectly less dependent on power stations that rely on fossil fuel consumption. In the long run, this can lead to lesser pollution as less fossil fuel is burnt. These are the non-monetary benefits that will follow Singapore as she progresses further. Through this, we have met our objective of coming up with the cost-benefit analysis of adapting the hydropower technology to DAltMech.
Chapter 5 Conclusion
One of the strengths of our project is that after thorough research and calculations, we found that our idea is feasible as it is able to power up about 65% of the HDB lightings in a block if it were to be installed in one water tank. Thus it can help HDB to cut down on 65% of the electrical bills.
Another strength of our project is that it is cost efficient and the fact that it is not restricted to geographical constraints renders the project easy to implement. Our proposed idea can be installed and suited to Singapore's landscape. If it were to be implemented in all HDB flats, it will not change the whole Singapore landscape drastically.
One limitation of our project is that due to security reasons, we were unable to access the rooftop of our HDB flats where the water tanks are located. Thus we were unable to take actual photographs of the pipes there and measure them ourselves. There is also a possibility of other pipes on the roof which are larger in diameter. We could then place a larger wheel there and generate much more energy.
Another limitation is that the costs of maintenance are difficult to estimate. Thus the overall cost DAltMech will be higher than expected, leading to a possibility that the savings generated DAltMech will not be able to cover the cost of implementation throughout its life of 10 years.
5.3 Future Directions
The electrical bills saved can be used for Research & Development to develop better housing for the people. Furthermore, as HDB plans to build more houses to accommodate more people in the future, our proposed idea can help to reduce the amount of money paid for the energy consumed by the LED lights, which in the long run can help HDB save up a large amount of money despite its high initial capital costs. In the national context, if most HDB buildings decided to implement our idea, it can significantly reduce the amount of electricity provided by the power stations, leading to reduced air pollution and conserving the fossil fuels for future generations as well.