Engineering problem solving team report

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1.0 Introduction

This report seeks to find a solution to Bendee Downs energy supply problem by considering several renewable sources of electricity production, as well as reducing consumption through the use of energy efficient infrastructure. The renewable energy solution will need to reduce the community's reliance on the main power grid and provide opportunities to local residents through employment and future tourism within the region. Additionally, the renewable energy infrastructure within the built environment and the employment opportunities must consider the social and cultural traditions of the Kooma community.

Potentially viable renewable energy design solutions will be considered and evaluated in this report. These design solutions may consist of solar, bio-digesters, building efficiency, wind energy and water energy. Several Key considerations will need to be addressed in order to define the primary objectives of the proposed design concept, which will include social and cultural impact, design criteria, environmental impact, technical feasibility, cost feasibility and human factor design.

Using a matrix decision evaluation method, each proposed design options will be assessed using a point system. The evaluation criteria include necessary and desirable key considerations within the proposed design. The evaluation of the proposed renewable energy source is important in order to provide the best-fit solution for the Bendee Downs energy problem.

Bendee Downs is a remote rural 24,000 ha property located in South West Queensland (28°S, 146° W), the site experiences high temperatures year round and little rainfall. Kooma Traditional Owner's Association Incorporated ( KTOAI) were given ownership of the land in January 2000 in the hope that it could be used as a cultural exchange center as well as a tourist attraction to provide the local indigenous community with jobs and other opportunities. The KTOAI spokesperson Cheryl Buchanan had this to say of the development..(EWB Challenge 2010)

"To use the properties as a 'regional hub', a training ground and base for the renewal of all our people and the protection and wise management of all of our traditional lands. We wish to meet their cultural responsibilities; and further to set an example in our country of the importance of a sustainable and continuing connection to country through inclusive management as their ancestors did and make Kooma people proud."

Key Considerations

Environmental- Bendee Downs is a remote and isolated community, and has a high level of sunlight in both summer and winter with a maximum temperature of 54°C on an average day in summer. There are also high winds and large water flows throughout the year, dusty conditions and lightning strikes which can impact on an alternative energy source design. Therefore, the final solution of designing a renewable energy source to replace the main grid must take into consideration the climate, remoteness of Bendee Downs and the capacity of the community to maintain the equipment. The natural environment must be sustained while developing the alternative energy supply source and the land must be managed in line with the community's culture and traditions.

Reliability- The current energy supply is sourced from one main grid power and a 9.8KW photovoltaic system installed in 2009 (EWB 2009), However, with plans to use Bendee Downs to accommodate more residents and visitors, the reliability of the current energy supply is going to be affected. The alternative energy supply must be built to last longer and not break easily. Furthermore, the remoteness and fluctuations in weather conditions make it more important for the supply source to be reliable because of the difficulty of maintaining it.

Sustainability- Our focus is to achieve sustainability by:

Being continuously mindful of reducing environmental impact and protecting the land and its cultural heritage.

Contribute to the development of the local community.

Provide sustainable energy sources which will provide income and or reduce costs for the community, preferably locally sourced.

Set an example of sustainable land management; (EWB 2009)

Provide opportunities for Kooma people so they can come back to country (EWB 2009)

Energy Production- An estimate of the total energy requirements is necessary for the design of alternative energy supply source to ensure the requirements of the community are met. For the Shearing Shed, the cooking facilities must be considered which will be used to provide thirty breakfast and dinner meals and up to 150 lunchtime meals.

Cultural - It is vital when designing an alternative energy supply source to keep in mind the diverse culture, language and strong cultural traditions of the Indigenous community in Bendee downs by taking into account cultural aspects in the design and protecting cultural sites. By improving the lifestyle of the Kooma people at Bendee Downs through reliable energy supply more opportunities for individuals may draw them back to their community. The Elders of the community must be respected by discussing with them the plan to develop an alternative energy source and the impact it may have on the community.

Cost Feasibility - Bendee Downs has a limited budget from which energy use and other necessary goods and services are paid. A cost efficient energy supply source is necessary to assist the community of Bendee Downs with energy saving, reduce its energy bills and utilize efficient appliances within budget.

2.0 Design Objectives

To supply a renewable clean energy source to support future tourism in the region and future development of the shearing shed.

Reduce running costs of the property and offset future energy costs associated with the development of the shearing shed.

Address the energy demands at bendee downs

Take care of the environment

Become self-sufficient

Lead by example

Improve the reliability of electricity supply

Provide alternative sources of income to help manage the property at bendee downs

2.1 Key Considerations

Environmental: Aesthetics, noise pollution, impact on the natural surroundings.

Reliability: Technology used must be able to withstand the harsh environment of Bendee Downs; it must also have low maintenance requirements due to the remote nature of the site.

Sustainable: Technology used must be environmentally friendly relying on renewable energy sources.

Energy Production: Based on data provided on the EWB design brief we have calculated an estimated daily energy usage as 217KWH. Detailed calculation can be found in appendix A - Bendee downs power usage

Cultural: Project must be coordinated with KTOAI and provide opportunities to local population as well as maintaining the heritage of the land.

Cost feasibility: Project budget must meet government grant allocation and be below the cost of upgrading the mains grid.

2.2 Existing Energy Sources

Diesel generator - nonoperational.

Main power grid Shearing Shed.

9.8KW photovoltaic Power system

2.3 Current infrastructure includes:

There are several buildings onsite listed below, however our main focus for this challenge is the Bendee downs shearing shed. "Traditional Owners we feel it is very important now to reclaim the shearing shed and to turn it into a really exciting place of learning, art and culture". (EWB 2009)

Shearers accommodation

Shower Block

Toilet Block

Wool Classing Room

Generator Room

Airstrip

Homestead

However our main concern is

3.0 Alternative Solutions & Evaluation Strategy

3.1 Alternative Solutions

3.11 Design Concept 1: Modified Building Design for the Shearing Shed (Building Energy Efficiency)

Objective

A shelter that will provide comfortable living conditions throughout the year with minimal demand of the clean renewable energy that is produced onsite.

Existing Shearing Shed

- All floorboards need replacement.

- 8 structural roof beams.

- 25% of roof needs replacing.

Features of the proposed Energy Efficient Building Design of the Shearing Shed

- Passive heating and cooling technologies and within the architectural design.

- Insulation.

- Water storage and grey water recycling.

- Sanitation and water disposal.

- Solar and thermal mass heating and cooling.

Key considerations

- Wide fluctuations in temperature.

- Weather patterns (rainfall, dust storms, tropical down pours etc.).

- Accessibility to building materials.

- Soil conditions

- Visual impact on the landscape.

- Cost

3.12 Design Concept 2: Solar Energy

Introduction

The key objectives of the Kooma Energy Project were to make Murra Murra and Bendee Downs as energy efficient as possible through:

- Investigating and implementing energy saving options.

- Installing solar energy panels to connect into the grid.

Currently the electricity Bills are too high and with the plans for additional people onsite and tourism, this design concept aims at reducing the load on the electricity grid and allows for future development onsite.

Objective

Reduce the demand for electricity at Bendee Downs by installing solar hot water and change current electric cooking practices by designing and building a solar oven.

Proposed Design Concept

- Installation of Solar hot water opposed to electric heating.

- Design and build a large solar oven.

Existing Setup

- Electric stoves.

- Assuming electric water heating.

Design Considerations

- Hot water system needs to be able to supply hot water for approximately 50-100 people per day.

- Solar cooker needs to be sufficient to provide thirty breakfast and dinner meals and up to 150 lunchtime meals.

- Solar cooker may be too slow and unreliable for commercial cooking.

Key Considerations

- Weather patterns (rainfall, dust storms, tropical down pours etc.) 

- Accessibility to building materials.

- Visual impact on the landscape.

- Cost feasibility: Project budget must meet government grant allocation.

- Efficiency.

3.13 Design Concept 3: Water energy from the Nebine River

Objective

Create energy by constructing a micro hydro system on the Nebine River.

Features

- Efficient energy source.

- Cost effective.

- No reservoir required.

Key Considerations

Environmental

- Minimal land requirements.

- Produces clean energy.

Reliability

- Power output is dependent on the flow of the river.

- Distance between the power source and where energy is required will affect reliability.

Sustainable

- The size and flow of the Nebine may restrict future site expansion as the power demands grow.

Energy Production

- Typically produce up to 100kW of power.

Cultural

- No reservoir is required so would have visual impact on the land.

Cost Feasibility

- Small scale hydro power systems can cost from $1000 to $20000.

3.14 Design Concept 4: Bio-digesters

Introduction

Anaerobic digestion is widely used as a renewable energy source because the process produces a methane and carbon dioxide rich biogas suitable for energy production.

Objective

To build an anaerobic digestion plant that will use food scraps, grass clippings and any bio degradable material to turn into biogas and produce enough power to supply Bendee Downs.

Features

- Clean energy source.

- Recycles household waste.

- Relatively easy to run and maintain.

- Reduces methane emissions from landfills.

Key Considerations

Environmental

- Is clean and friendly on the environment.

- Uses household waste and animal remains to produce the energy.

- Optimal operation temperature is 47-51 degrees (suitable to Bendee Downs environment).

Reliability

- Is reliable as it produces energy on its own with little help.

- Produces consistent amounts of energy per kilogram of material.

Sustainable

- The atmosphere at Bendee Downs means that the system may require upgrades depending on production output of energy.

Energy Production

- 730 to 1300 Kwh per dry ton of food applied.

Cultural

- Might have an impact on the culture of Bendee Downs as it might visually affect the natural surroundings.

Cost Feasibility

- Can be anywhere between $450 000 and $1 250 000 depending on size of plant.

- Most effective size plant would be about $730 000.

3.2 Concept Evaluation

3.21 Key Evaluation Criteria

3.21. Design Criteria

The following design criteria have been formulated in conjunction with the design objectives in section 2.0. For a particular design solution to be viable it must at least comply with the necessary criteria which are the minimum specifications that have been identified by the client. All desirable criteria are additional specifications identified by this project team, which we consider will potentially add additional value to the design and help us to further evaluate other options.

All design concepts will be evaluated using the below evaluation matrix figure 1 which corresponds to the criteria below. Each concept is scored by a numbering system which identifies how many necessary and desirable criteria it complies with.

Our design team will evaluate each design concept based on the total number of necessary and desirable criteria it complies with, bearing in mind that for a design concept to be viable it must at least comply with all the necessary criteria.

Must rely on renewable source of energy, solar, wind etc... NECESSARY

Must be able to withstand environmental stresses such as flooding, storms, bush fires. NECESSARY

Must have safeguards in place to prevent injuries in operation. NECESSARY

Meet relevant Australian standards (building code/ manufacturing). NECESSARY

Aesthetics. DESIRABLE

Low impact manufacturing, recycled materials used in solutions. DESIRABLE

Minimal use of local natural resources (water, land use). DESIRABLE

3.22. Technical feasibility

Must provide reliable and properly conditioned electricity supply that can be used by appliances identified in this report. NECESSARY

Must supplement main grid usage by at least 50%.  NECESSARY

Must produce no pollutants or damage the natural ecology of the land. NECESSARY

Expandability for increases electrical loads in the future. NECESSARY

Provide 24hr hour supply year round. DESIRABLE

Produce all electricity needed. DESIRABLE

To be maintained by local Technicians. DESIRABLE

Minimal installation time and impact on site during construction. DESIRABLE

3.23 Human factor feasibility

Training in the proper use of the solution must be included to guaranty efficient operation. NECESSARY

Must be safe to operate and maintain. NECESSARY

Must not pose a hazard to public (noise, pollution, electrocution). NECESSARY

3.24. Social Cultural feasibility

Be aware of impact on the visual landscape and cultural sensitivities. NECESSARY

Must provide local employment opportunities (security, maintenance). NECESSARY

3.25. Financial feasibility

Raises revenue, excess electricity sold into grid. DESIRABLE

Preferably source labor and materials locally. DESIRABLE

Pays for itself in short time. NECESSARY

Government subsidy available. DESIRABLE

Ongoing maintenance costs. NECESSARY

Meets assumed budgets constraints. NECESSARY

3.3 Evaluation Matrix

Solar

Building Design

Hydro

Bio Digester

Design

Necessary (0-4)

Desirable (0-3)

4

1

4

3

3

2

4

1

Technical Feasibility

Necessary (0-4)

Desirable (0-4)

4

2

4

2

2

3

2

2

Human Factor

Necessary (0-3)

3

3

3

3

Social / Cultural

Necessary (0-2)

2

2

1

2

Financial

Necessary (0-3)

Desirable (0-3)

3

2

3

2

3

2

2

1

Totals

Necessary

Desirable

16/16

5/10

16/16

6/10

12/16

7/10

13/16

4/10

Figure 1 - Evaluation matrix table

4.0 Proposed Solution

After assessing the design concepts against the criteria and key considerations in our matrix evaluation table (refer to section 8.1 Appendix B - matrix evaluation table - Figure 1), Team 8s final design concept is to incorporate solar technologies with a modified building design of the shearing shed at Bendee Downs. By combining these solutions, Bendee Downs will be powered more efficiently through a renewable energy source, the sun. Solar energy is better suited to the Bendee Downs site with its year round sunlight, than other alternatives such as water energy from the Nebine River and the bio-digesters. (ref rain fall / wind sunlight data for bendee).

The household size, cost, space available, existing water heater, available energy sources and local climate were considered in determining the final proposed solutions which are the evacuated tube solar system with the modified building design of the shearing shed. The proposed design solutions are able to withstand environmental stress, rely on a renewable source of energy reducing pollution and reduce the use of local natural resources.

Evacuate Tube Solar hot water System

With such a broad range of solar power systems to choose from, a comparison was conducted on several potentially suitable systems for Bendee Downs. Refer to section 7.4 - Appendix A for a full comparison and Appendix B for a comparison of the advantages and disadvantages of the two most suitable systems, the flat plate collector system and evacuated tube system.

The findings showed the flat plate collectors and the evacuated tube collectors have very similar attributes. They both absorb the sun's rays through collectors on a roof. If there was certainty based on previous years that the climate and weather conditions would be sunny, all year round, the flat plate collectors would be more efficient, however temperatures can be as low as 4 degrees Celsius in winter.(Source: http://www.exploroz.com/Places/39464/QLD/Bendee_Downs.aspx)

Furthermore, taking into consideration that energy will need to be provided to approximately 30 people each day and to a number of appliances and hot water, the evacuated tube system appears to be more efficient.

This is a gas boosted system that is capable of absorbing sun's rays even on a cloudy day. Its technical feasibility proves to be reliable, compared to the other solar power systems and the amount of energy produced is enough to supply to Bendee Downs all year. Maintenance costs are low and the system is safe to operate. It is less costly to use and pollution friendly. Combined with a modified building design of the shearing shed all energy can be supplied from these combined solutions, reducing costs to the community and providing a reliable, low maintenance energy supply source.

This system is gas boosted and operates at a higher efficiency because the sun's rays are perpendicular to the tubes most of the day increasing the absorption of the sun's radiants. This type of solar system has low maintenance and is cheaper to run in the long run than the other hot water systems. Due to its highly efficient absorption of solar radiation even during overcast conditions, combined with excellent insulating properties, solar tube collectors can heat water all year round. (Source: ingenero)

The solar hot water system should face solar north with an orientation deviation of up to 45° from north and ensure that solar collectors are not shaded by trees or anything else that may shadow the collectors, particularly in winter when the sun is low. They need to be at an angle to the horizontal to maximize the amount of sunlight falling on the panels. The angle may vary from 17.5 degrees Celsius to 53 degrees Celsius. The angle of the collectors may need to be increased during winter and decreased during summer. A technician will need to make the adjustments, adhering to health and safety regulations.

Precautions must be taken during summer to prevent water from boiling, by using a heat dissipation device and a mixing valve to reduce water temperature at the tap to safe levels. (Source: Insloar.com.au)

Some advice to give to the community and users of the system is to carry out jobs that need hot water early in the day so that the water left in the tank will be reheated by the sun, ready for use at night.

Solar panels must be regularly cleaned to remove dust, which can be done with a broom with some detergent. (CONSIDER WHO WILL DO THIS AND HOW THEY WILL REACH THE PANELS)

The type of system that is most suitable for Bendee Downs depends on the number of people it will need to provide for and the number for appliances it will need to power. The Apricus 250L gas boosted system with 22 evacuated tubes solar hot water system is suitable and has the following specifications as listed in figure 1:

Product description

22 tubes collector

Overall length - 1

1980 mm

Overall height - 2

156 mm

Overall width - 3

1636 mm

Absorber area - 4

1.76 m ²

Aperture area - 5

2.07 m ²

Gross area

3.24 m ²

Gross dry weight - standard frame

71.3 kg

Standard pressure rating

800KPa or 116 psi

Fluid capacity

0.55 L

Recommended fluid flow rate

2 - 3 l/min

Collector efficiency

73 %

Gas Boost

Eternity 26

Gas input

195 MJ/h

water supply pressure

150 to 1200 KPa

Gas connection

20 BSP

Water connections

15 BSP

Ignition

Electronic

Gas type

Natural Gas/LPG

Electrical supply

240VAC

Energy ratings

5.44

Dimensions

520H x 170D x 350W mm

Weight

16 kg

Storage tank

250 Litres Tank

Size in litres (Actual)

250 (264)

Height

1620 mm

Diameter

580 mm

Weight empty

53 kg

Weight full

317 kg

Hot water outlet

1191 mm

Return flow to tank

370 mm

Cold water inlet

168 mm

Electric cable entry

143 mm

Optional Extras

High temperature tempering valve

Low angle frame can be used to raise the angle by 12 degrees

Mid angle frame suitable for flat roof or low pitched roof

High angle frame providing an adjustable range of 27 to 50 degrees

Wall mounting - the low, mid or high angle kits can be used to mount a collector on a wall

Pole mounting allowing orientation and angle to be easily set when a roof or wall mount is not suitable

Figure 1 - Apricus 250 Technical Specifications

(Source: http://www.energymatters.com.au/apricus-250l-gas-boosted-22-evacuated-tubes-solar-hot-water-p-269.html)

Cost

The Apricus 250L costs approximately $7,800 for each panel of 22 tubes plus mounting costs. Total cost is approximately $31,200 less Government rebates. The life expectancy of this system can range from 10 to 20 years and has little if any maintenance costs. The comparison of savings made in energy costs in the long run and the minimal impact on the environment makes this the best proposed solution for Bendee Downs, combined with the modified building design.

Modified Building Design

The second proposed solution in addition to the solar technology is a modified building design which can contribute to reducing the amount of energy consumed by the residence at Bendee Downs. Through energy efficient housing design the amount of natural airflow would increase along with shading, orientation, insulation and ventilation of the shearing shed. This can be achieved by replacing the floorboards, replacing the structural roof beams and 25 per cent of the roof. With these modifications, passive heating and cooling technologies can be implemented within the architectural design, insulation will assist with keeping the shearing shed cool in summer and warm in winter. The reliance on air conditioners, electric heating and other high energy items can be reduced.

Modifying the building design will create more work for the residence but because it impacts on the visual appearance of the shearing shed, close consultation with the residence will take place to ensure the cultural aspects of Bendee Downs are not interfered with.

5.0 Testing and Evaluation

6.0 Actions

The following actions must now be considered from this point on for successful project implementation.

Procurement of materials and services

Tender process

Dowling, David Graeme (2010, p. 478) This process results in companies submitting a tender (detailed quotation) to undertake specified work or provide services.

An advertisement must be placed for local businesses to submit tenders for providing materials and services considering the following criteria in selection:

Cost

Environmental credentials of supplier

Performance and efficiency of panels provided

Timeframe of installation and delivery of materials

Warranties offered.

Creating a Contract between the different parties involved in the project

Dowling, David Graeme (2010, p. 479) A contract is a legally binding agreement between two parties that requires the parties to perform certain obligations. It will set out the requirements and obligations expected to be complied with, or undertaken by, the respective parties.

Contracts will need to be created between the engineers, material suppliers/installers and the KWOI representatives of the Bendee Downs community. With these in place any problems that may arise during implementation can be more effectively resolved.

Research of Australian Standards to be followed during implementation

The following standards must be adhered to during installation of and testing of project:

AS/NZS 4509.1:2009 

Stand-alone power systems - Safety and installation 

AS/NZS 2712:2007 

Solar and heat pump water heaters - Design and construction 

AS 60068.2.9-2003 

Environmental testing - Tests - Guidance for solar radiation testing 

AS 4234-1994

Solar water heaters - Domestic and heat pump - Calculation of energy consumption 

Survey site

Perform solar radiation survey at the proposed site over a set period of time to determine solar activity. This will help more clearly define the number of panels necessary and the effect of overcast weather on output. Survey site and make sure there are no obstructions that can block sunlight reaching solar panels.

Community Consultation

From this point forward the Bendee Downs community must be kept informed as to how the project will proceed, what exactly it is and addressing any concerns that they have. The information presented must be tailored to the target audience not engineers.

This information can be distributed in a number different ways such as:

Flyers

Media, internet site, radio, TV

Town hall meetings

Surveys of opinions and focus groups can also be conducted in the community to gauge people's reaction to the proposed design.

7.0 Appendix A

7.1 Estimated Maximum load table - Next 5 years

From the information provided, we must be able to at least accommodate the following

30 x Breakfast meals

30 x Dinner meals

150 x lunch time meals

Additional cool / heating for tourists

Additional pumping

Item

Quantity

Power rating

Average usage (hrs)

Total power usage per day

Computers

10

250

10

25000

Air-conditioning / heating

10

1200

8

96000

Additional water pumps

1

400

16

6400

Fridge

1

540

24

12960

Freezer

2

475

24

22800

washing machines

1

500

4

2000

dryer

1

4000

2

8000

 

 

 

 

 

 

 

 

 

 

 

 

 

W

173160

 

 

 

KW

173.16

7.2 Estimated Maximum load table - Current

Item

Quantity

Power rating

Average usage (hrs)

Total power usage per day

 

 

 

 

 

Electric hot water

2

2700

12

64800

Electric stove

2

2600

6

31200

Water pump

4

600

16

38400

lighting / fans

1

400

16

6400

fridges

2

540

24

25920

freezers

2

475

24

22800

washing machine

1

500

4

2000

Dryer

2

3600

2

14400

General cooking appliances

1

200

6

1200

 

 

 

 

 

 

 

 

WH

207120

 

 

 

KWH

207.12

7.3 Bendee Downs Power usage / cost

- Current electricity bill $6000

- When the solar system is not generating electricity, such as overnight, or when Bendee Downs is using more electricity than the solar system is producing, electricity will be imported from the electricity grid at a cost of $0.18843/kWh.

- Electricity that is generated by the solar system and not used will be recorded by a meter and exported to the electricity grid, earning $0.44/kWh.

Given that the electricity bills are recorded as to high we can assume that the solar panels cannot produce enough power alone.

$6000 / $ 0.18843= 31,842.00 KHW per Quarter purchased from electricity grid.

= 167.50 KWH per day .

There is a 9800W Solar Panel system currently installed at Bendee Downs.

Therefore assuming average optimum production of 5hrs per day due to sunlight and conditions, the solar panels produce.

5 x 9.8KWH = 49 KWH per day.

or 

190 days x 49 = 9310 KWH per quarter.

Therefore total power demand is estimated at

9,310.00 + 31,842.00 = 41,152.00 KWH

Or

KWH per day....

7.4 - Solar hot water comparisons

SOLAR HOT WATER SYSTEMS

1. Flat plate collectors

2. Evacuated tube solar hot water system

3. Heat pump solar hot water system

DESCRIPTION

Collects radiant heat from sun to heat water through flat plates on roof.

Series of highly efficient tubes which absorb the sun's rays and retain the heat with higher heat retention rate.

Uses a bit of electricity to collect the sun's heat in the atmosphere.

FEATURES

Flat panels can weigh up to 200kg plus, which requires a specifically modified roof top to accommodate for this.

This electric boosted system operates at a higher efficiency than the flat panels because the sun's rays are perpendicular to the tubes most of the day increasing the absorption of the sun's radiant's. Weighs much less than the flat panels (around 96kg).

copper liquid filled heating element inside the vacuum tube

These tubes are capable of absorbing up to 92% of the heat from the sun. They absorb up to 40% more heat than a flat plate collector of the same surface area.

The system is also fitted with a 3600W element to provide back up during prolonged cloudy or cold weather or unusually high water usage

The pump comes on to circulate warm water if the manifold water temperature drops to 3C and turns off when it reaches 5C.

The hot water produced in the manifold is circulated down to the storage tank when its water temperature is 9C hotter than the tank temperature. It shuts off when the temperature difference is 5C or less. The pump will remain off once the tank temperature reaches 74C.

There is a pressure temperature relief valve on both the manifold and storage tank to vent steam should the temperature in either location reach 99C. There is also a solar tempering valve which mixes cold water with the tank water to maintain the water temperature to your taps at 50C to prevent the danger of scalding.

(Source: www.rpc.com.au)

Are efficient and economical water heaters

COST TO PURCHASE

For $8000, approximately 10 flat panel collectors can be purchased to cover a gross surface area of 20sq m (Source: solarhome.com.au).

315L electric boost 30 evacuated tubes is approx $6000 ( Source: http://www.enviro-friendly.com/evacuated-tube-solar-hot-water.shtml)

(need to look at how many would be required)

Approx $3500 each (need to look at how many would be required)

(REFERENCE)

INSTALLATION COSTS

Costly to install plates on the roof.

No installation costs, connection is similar to hot water system.

WHOLE OF LIFE COSTS (MAINTENANCE)

Low maintenance.

Low maintenance, cheaper to run in the long run than the other hot water systems.

Minimal maintenance costs.

APPROXIMATE MAXIMUM POWER SUPPLY

One collector will collect approximately 2829kWh of energy per year in Brisbane.

( Source: solavis)

Due to its highly efficient absorption of solar radiation even during overcast conditions, combined with excellent insulating properties, solar tube collectors can heat water all year round.

(Source: ingenero)

Dependent on absorbed heat.

CAN THE POWER DEMANDS OF BENDEE DOWNS BE MET

May be able to meet the power demands but with uncertainty.

Can meet the power demands of Bendee Downs, perhaps even exceed it.

Does not provide enough power required for Bendee Downs

LIMITATIONS

these types of collectors are much less efficient for domestic water heating. (Source: http://en.wikipedia.org/wiki/Solar_water_heating

The collector plates are inefficient when the sun strikes at different angles. The sun needs to be directly overhead the collector plates at midday for maximum efficiency.

Still requires small amount of electricity (approximately 5 watts).

Still requires small amounts of electricity to run.

IMPACT ON ENVIRONMENT

All reduce reliance on fossil fuels reducing pollution

7.5 Project Management plan

8.0 Appendix B

- Design concept Evaluation

Solar

Building Design

Hydro

Bio Digester

Design

Necessary (0-4)

Desirable (0-3)

4

1

4

3

3

2

4

1

Technical Feasibility

Necessary (0-4)

Desirable (0-4)

4

2

4

2

2

3

2

2

Human Factor

Necessary (0-3)

3

3

3

3

Social / Cultural

Necessary (0-2)

2

2

1

2

Financial

Necessary (0-3)

Desirable (0-3)

3

2

3

2

3

2

2

1

Totals

Necessary

Desirable

16/16

5/10

16/16

6/10

12/16

7/10

13/16

4/10

Figure 1 - design concept evaluation

Advantages

Flat Plate Collectors

Evacuated Tube Hot Water System

In areas with much sunshine and solar heat, a flat plate collector may be more efficient especially if its price compares favorably with that of an evacuated tube collector.

More of the sun's rays absorbed when cloudy than the flat plate or when there are low temperatures (e.g. during winter)

Tubes are strong

Light panels (96kg)

Minimum heat loss when liquid temp in collector is above ambient

Absorber plate area exceeds evacuated tubes'

Based on absorber plate area, many evacuated tube systems are more efficient than equivalent flat plate systems.

In extremely hot climates, flat-plate collectors will generally be a more cost-effective solution than evacuated tubes.

Evacuated tubes can therefore maintain their efficiency over a wide range of ambient temperatures and heating requirements.

There are minimal ongoing costs associated with this system, and heat is absorbed even on an overcast day.

Disadvantages

Flat Plate Collectors

Evacuated Tube Hot Water System

Heavy compared to ETHWS (approx 200kg each, SIZE)

Absorber plate area to gross area ratio is smaller (typically 60-80% of gross area) than for flat plates (Source: http://en.wikipedia.org/wiki/Solar_thermal_collector)

Is boosted by gas

9.0 Reference List

Author Unknown, (2010) "EWB Challenge 2010" viewed 10th September 2010 http://usqstudydesk.usq.edu.au/file.php/15777/pub/Assessment/EWB/EWB_Challenge_Design_Brief.pdf

Engineers without borders Australia 2009 - Kooma Energy project Announcementshttp://www.ewb.org.au/announcements/148/10209

Dowling, David Graeme 2010, Engineering Your Future an Australian Guide, John Wiley & Sons, Australia.

Department of Local Government, Planning, Sport and Recreation

Energy Efficient House Design for Tropical Queensland August 2005

http://www.dip.qld.gov.au/docs/planning/building_codes/housing/energy_efficient_housing.pdf

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