sustainable design for appledore island

7/23/2019 Sustainable Design for Appledore Island

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Sustainable Design

for Appledore IslandFinal Alpha Team Project

Cyara New

Reid BalkindAbhi GuptaValerie Katz

Yungton Yang


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Introduction

Appledore Island is located about six miles off the coast of Maine and New

Hampshire; the island is completely self-sufficient and is home to the Shoals Marine

Laboratory. Being self-sufficient, it produces its own power and freshwater and it

manages all of its wastewater.

To generate power, Shoals Marine Laboratory uses one of its three diesel

generators, arrays of solar panels, and a 7.5 kW Bergey Wind Turbine to provide

power in winter months when wind is more prevalent and the sun less intense. In

an effort to make the island more sustainable, the Alpha Team aims to move

Appledore Island away from diesel generators and towards cleaner sources of

energy.

Freshwater supply comes from a well that is twenty feet deep with a six-foot

diameter. The water from this well is treated by filtration and chlorination. If the

water level in this well gets too low, however, there will be mixing between this

fresh well and a saltwater watershed, making it unsuitable for consumption. To

prevent this during dry summers when the well is insufficient and cannot meet the

freshwater demand, a reverse osmosis unit desalinates salt water, a process that is

energy intensive. The Alpha Team aims to facilitate this process by producing the

requisite additional energy in a sustainable way, or determine a new process to

implement altogether.

Finally, the island treats wastewater through four septic systems, three leach

fields, four composting toilets, and a FRICKle filter that treats gray water. The

FRICKle filter contains foam media on which bacteria grow. These bacteria respire


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anaerobically and purify the water. All systems are therefore quite sustainable, but

there is room for additional considerations as there are still inefficiencies with the

FRICKle Filter.

The mission of Shoals Laboratory is toprovide education and research

programs that advance the 1) understanding of marine and coastal ecosystems and

2) development of sustainable solutions to environmental challenges (The Mission

of the Shoals Marine Laboratory). The Alpha Teams goal is to facilitate Shoals

Laboratorys second goal and help tocontinue the islands efforts of becoming

increasingly sustainable. This will be accomplished through the implementation of

sustainable designs to improve the islands energy systems by shifting away from

diesel, a freshwater supply independent of the existing well, and a better

wastewater treatment system.

Energy

While Appledore Island has made strides in its energy production via the

implementation of solar panel and a wind turbine, it still uses some diesel for fuel.

Several solar arrays are in place on top of dorms two and three, and a 7.5 kW wind

turbine was brought onto the island in 2007. Diesel fuel is still being used however

to supplement the energy provide via these sustainable methods. Based on the

average generator capacity utilization graph (Appendix A) it was determined that

the island uses diesel generators to obtain 652.5 kWh/day. At this rate the

Appledores greenhouse gas footprint is 163 kg CO2/ day. (Appendix A)


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Technologies Considered

To provide the island with more sustainable sources of energy to meet the

demand of 652.5 kWh/day currently being met by diesel fuel engines, several

green energy systems were considered. Solar panels with storage were considered

to harness solar energy, a wind turbine with hydrogen storage, fuel cells, and

batteries were considered to harness wind energy. Hydroelectric, geothermal, and

biomass systems were also considered.

Figure 1. Comparing Energy Type to Annualized Costs

In comparing the several energy systems available, the three cheapest

options were hydropower, solar with storage, and biomass. A detailed calculation of

the annualized costs can be found in Appendix B.

Wind power was also ruled out because the island has a wind turbine, and it

is primarily used in the winter, when the wind is the strongest. As the Alpha Team

seeks to replace diesel generator usage, most of which is during the summer on

$0.00

$2,000.00

$4,000.00

$6,000.00

$8,000.00

$10,000.00

$12,000.00

$14,000.00

Solar withStorage

Wind withStorage

Geothermal Hydropower Biomass (BFB)

Energy Source vs Annualized Cost


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Appledore, it is not reasonable to install another wind turbine. The annualized cost

of wind power was determined to be $13,030.17.

For a geothermal power plant, the Alpha Team recommends a flash steam

power plant because at 235C (Lecture Slides 2-25 Slide 5), the pressure of the

steam would be 100000 kPA (Appendix B Geothermal), and at this pressure steam

becomes a liquid. Flash steam must be 175-235 degrees, so the well needed to

extract this high temperature superheated liquid would be 2.5-3.5 km deep, making

geothermal an impractical endeavor. The cost of geothermal power was determined

to be $13,138.14 per year.

Hydroelectric Energy

Hydroelectric was another option explored, with an abundance of water

surrounding the island providing the requisite environment for this system.. All

calculations are available in Appendix B Hydroelectric. With the significantly low

annualized cost of $4,756.58 per year, hydroelectric was a very affordable choice for

Appledore. After calculation, however, is that it requires a massive area of 2,250,000

m2, or 617 acres. Considering the island spans only 95 acres, the proposal for such a

large basin is unreasonable. It would impede the marine activities that take place

around the island and seriously hinder research conducted by Shoals Laboratory.

Furthermore, the system would need to be located far enough from the island and

large enough (about 0.86 square miles) that it would not be worthwhile. The basin

would need to be 6 meters deep with a channel that is 30 m x 5 m, and would need

50 turbines each with a 0.108 m radius.


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Solar Energy

The Alpha Team recommends solar energy with storage to as a possibility to

eliminate diesel use because solar power is already used on the island and

extending this infrastructure is very viable and simple. All calculations are available

in more detail in Appendix B - Solar. Also it is cost effective at$9,880.07 per year.

We recommend BP 3160 solar panels whose max power output is 160 W per panel,

this equates to 836.8 Wh produced per panel per day. Because Appledore only

averages 5.23 peak sun hours per day, additional energy must be stored (Lecture

Slides 2-9 Slide 19). Accounting for inefficiencies with the inverter and battery, solar

panels must collect 1028.26 kWh/day. This equates to 1229 panels that would cover

approximately 16668 ft2.

Because solar panels are most efficient when they are perpendicular to the

suns rays these panels should be placed at an angle. However, during the summer

months, the sun is higher in the sky, and thus the panels should have a tilt less than

45 degrees. It is recommended to place solar panels at the locations latitudinal

angle, + 15 degrees, and so for a summer bias we subtract 15 degrees and

recommend that these panels be placed at about a 28 degree angle (Lecture Slides

2-9 Slide 17). At this angle the panels would cover 14,722 square feet. The

advantages of solar energy remain the time of maximum energy usage; the summer

provides the maximum output. The other advantage remains that the infrastructure

already exists. The problem, however, is the large amount of space needed to

accommodate the panels. However, in comparison to other sources, area usage is

low, and cost is not severely high. Our recommendation is that these panels be


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placed on top of buildings with appropriately slanted roofs before resorting to open

space on the north side of the island.

Biomass Energy

Biomass energy was the final option considered. Biomass energy very simply

utilizes different waste material for energy generation, with an efficiency of 90%

(What to Expect from Biomass Boiler Systems). There are many sources of fuel for

biomass systems, inclusive of wood pellets, wood chips, human and animal waste,

crop residue, and municipal solid waste (Types of Biomass Fuels). Furthermore,

there are two main types of biomass systems that the Alpha Team considered: the

combined cycle and the bubbling fluidized bed. In the first system, waste is burned

and the heat generated is used to boil water, which then turns into steam and turns

a turbine to produce electricity. The main fuel used is carbon based options, which

usually consists heavily of wood related waste and pellets. In the second system,

solid particles levitate above liquid moving at a low velocity, causing the particles to

act as a fluid. The bubble and fluid movement causes interactions with high heat

transfer, allowing for water to be boiled, which turns into steam and turns a turbine.

The main fuel used in this system is wood, plant remains, and solid waste. The Alpha

team recommends the utilization of the second system, simply because of the higher

number of feedstock options, and because the capital cost of a BFB is half as much as

a CC system ($4,114 vs $8,180) (Capital Cost for Electricity Plants). All calculations

are outlined in Appendix B Biomass. Because Biomass systems are generally used

for large scale energy production, it seems unfeasible for Appledore Island to

implement this system. If there was a larger energy need, biomass would be a viable


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option. Furthermore, biomass systems require a large amount of space for the

boilers and fuel storage (Advantages and Disadvantages of Biomass). Currently,

biomass energy would have an annualized cost of $11,846.90, but this is not

considering the cost of resources. Biomass fuel is very expensive, and even with the

use of waste from the island, fuel would need to be imported.

Energy Conclusion

With the technologies looked into: solar power, hydropower, and biomass

considered, solar was determined to be the best solution. Hydropower is the

cheapest option, but it is very space intensive. Biomass is economically viable for

large energy production needs, but for the small scale of Appledore is not feasible as

biomass may need to be imported. Solar power was determined to be the best

option. It is relatively cheap, and reliable as sun input is reliable in summer months.

Additionally solar arrays are already in place in Appledore, so extending this

existing system makes most sense.


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Drinking Water Treatment

Celia Thaxter Island Garden

Each season Shoals Laboratory uses about 157,029 gallons of water sourced

from both a well on the northern region of the island, as well as a reverse osmosis

unit (2014 Sustainable Energy Report 46-47). In the summer of 2014 the size of the

watershed was estimated to be 53,840 ft^2, but this well must be supplanted by a

reverse osmosis unit because if the water in the well runs too low, the risk is run of

contamination with saltwater.

Water conservation efforts on the island are evident as residents are

restricted to only two navy style showers a week in which water only runs during

rising. These efforts however can be improved with the Celia Thaxter Island Garden.

This garden was first cultivated in the late 1800s when by Celia Thaxter whose

father established a hotel on the island. She had a love for gardening and art, and her

prose and poetry received considerable fame. The garden drew in many artists and

writers and for this reason holds great historical value and is worthy of being

preserved (About Celia Thaxter's Island Garden). The flowers in the garden need

freshwater, however when water is limited it is difficult to justify using fresh well

water to cultivate the blooms when it is needed elsewhere. Our proposal is a rain

water collection system estimated roughly to cost around $4,000. The island

conducts tours of the garden seven times a summer, each tour with 24 people, and

each person is charged 100, this brings in a total $16,800, and it is reasonable to

have some of this revenue directed towards a system to make the garden more

sustainable.


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Because the well currently on the island is insufficient in dry years, other

freshwater sources are necessary. To meet the additional freshwater need options

considered included: digging another well, slow sand filter, rapid sand filter, and

solar distillation. Reverse Osmosis is currently in use on Appledore but uses a high

level of energy, making it necessary to consider other options. Solar distillation was

possibly the most environmentally friendly option as once it was built it would only

require upkeep to run and no further inputs. Comparatively, while the two types of

filtration would require upkeep and inputs to keep it running, they would still be

relatively minor complications for an operation this small. These two methods

would also take up very little space on the island and dont depend on

uncontrollable variables such as the sun.

Figure 2. Filtration System vs Annualized Cost

The rapid sand filter cost includes the cost of system installation, sand,

backwashing, chlorine, and the contact tank. The slow sand filter cost includes the

$0.00

$400.00

$800.00

$1,200.00

$1,600.00

$2,000.00

Slow Sand Filtration Rapid Sand Filtration Solar Distil lation

Filtration System vs Annualized Cost


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cost of the system installation, sand, chlorine, and contact tank. The solar distillation

cost only includes the cost of system install, per nature of the technology. All

calculations are outlined in Appendix C.

With slow sand and rapid sand filtration systems already partially or

completely in place on Appledore, the Alpha Team believes it is in the best interest

of the island to continue working with sand filters. However, because solar

distillation is so cheap, the Alpha team performed an analysis on all 3 systems.

Solar Distillation

Solar distillation utilizes solar energy in order to evaporate and purify salt

water. Because this process utilizes salt water versus fresh water which the other

two require it would put much less of a strain on the island. The fresh water source

has steadily grown smaller which poses a potential problem. This method uses solar

heat to evaporate salt water. A black heat-absorbent surface is placed at the bottom

of the container to help capture heat inside the container more quickly. The

evaporated water then condenses on the cool plastic of the top part of the container.

During the condensation part of the process much of the heat energy is reabsorbed.

This evaporated water is now pure of salt and bacteria and will drip down the side

to a collection basin where it can now be used to drink safely. This process isnt very

time efficient and does require a comparatively large area to hold all of the housings.

The upside to this process though is that it doesnt require any further treatment to

the water and the solar distillation housings only require the water to work. It is

also environmentally friendly in this regard. The annualized cost of the system is


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$617.51, which is outlined in Appendix C Solar Distillation. However, the size

required is 2592.5 m2, a very large section of space.

Rapid Sand Filtration

Rapid sand filtration utilizes porous media filtration in order to clean the

water of colloidal and suspended solid. It requires fresh water to run as it wont

clean the salt out of sea water. The water is run through a tank containing sand and

uses gravity to pull it through. The sand will remove any suspended solids in the

water. As the sand gets more clogged up the water will experience head loss or a

loss of pressure. In order to clean the sand it must be backwashed. Backwashing is

when water is forced the opposite way through the filter. The water will cause the

sand to expand and release all of the collected waste from the water. This process

does require energy to run. After the water is filtered through the sand it still may

have bacteria present, such as cryptosporidium or giardia lambia. Thus, it requires

disinfection which is accomplished with the use of chlorination. The water is sent to

a contact tank where it is exposed to chlorine that should kill varying levels of

bacteria depending on the amount of time spent in there. After leaving the contact

tank the water will be safe enough to drink. This process is very time efficient but

does have its fair share of downsides. First of all, it requires fresh water to run.

Second of all, it requires energy and chlorine to run which contribute to annual

costs. Another problem is that it does require the use of chemicals to clean the water

which is an area of concern for many people. The Alpha Team calculates a rapid

sand filter would need to be 0.043 m2. It would also require 78.792 kg of sand

initially and then 3.747 kg of chlorine per year with a contact tank with an area of at


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least 275 gal, and 3.5 kw/day to backwash. With these factors in mind the

annualized cost of a rapid sand filter would come out to $1,730.99. All calculations

are outlined in Appendix C Rapid Sand Filtration.

Slow Sand Filtration

Slow sand filtration is a process very similar to rapid sand filtration. Rather

than utilizing backwashing the sand, though, the top layer of sand must be replaced

every few months. This process has all the same pros and cons of rapid sand

filtration except for discrepancies in the price to run it and the fact that slow sand

filtration does require its consumers to be careful of water usage, as it does take

time for water to cleanse under this system. The slow sand filter would need to be

2.17 m2and would require 7000 kg of sand with the top 2 inches of it being replaced

yearly. It would also require the same amount of chlorine and a contact tank as the

rapid sand filter. This means that the slow sand filter comes out to be $859.26

annually. All calculations are outlined in Appendix C Slow Sand Filtration.

Drinking Water Conclusion

In conclusion, the Alpha Team recommends the use of a slow sand filter. It is

a cheap option for water purification and requires little space to operate. Although

the use of chlorine is a downfall of this process, the benefits are greater than the

losses, and ultimately beats out the other technologies. Rapid Sand filtration is very

expensive in regards to the other choices, while solar distillation is cheap and does

not use chlorination, but requires a large amount of space that would be difficult to

find on Appledore.


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Wastewater Treatment


The islands wastewater systems at the time being are relatively sustainable,

however the FRICKle filter has been having issues due to its design, so the Alpha

Team proposes wastewater treatment options for effluent from primary settling.

Two general methods were considered: combined blackwater and greywater

treatment and separate blackwater and greywater treatment. In combined

treatment systems, septic tanks are proposed for primary treatment, where solids in

the wastewater will settle and be anaerobically digested, with remaining liquid

waste being passed to a secondary treatment system. These secondary treatment

systems include constructed wetlands, leach fields, rotating biological filters, and

trickle filters. This provides 4 options in combined treatment, with the septic tank

paired with each secondary option. For separated systems, a composting toilet

would be used to separate and collect blackwater, with the remaining greywater

being treated in a secondary system, either constructed wetlands or leach fields.

This provides 2 separated treatment options, with the composting toilets paired

with the two secondary options. The Alpha Team compared the annualized costs of

the 6 options presented, and proceeded to conduct a more thorough review of the

top 2 options. All calculations are outlined in Appendix D.


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Figure 3. Wastewater Treatment Options vs Annualized Costs

The Alpha Team decided to consider two technologies for a combined system. We

would use either a septic tank with a constructed wetlands or a septic tank with a

leach field as they were by far the cheapest options.

Septic Tank

Septic Tanks are necessary for primary treatment of wastewater. In the

septic tank, solids settle and are anaerobically digested. The purpose of the septic

tank is to collect the solids and remove large pieces of material such that the

secondary treatment option can consume the remaining waste and cleanse it such

that consumption or environmental discharge is acceptable. The Alpha team

calculates that the annualized cost of this system is $1,193.30, compared to the

other primary treatment option of composting toilets which cost $6,708.59, nearly 3

times as much as septic tanks. Comparing size, the septic tank was 2400 gal, while

22 composting toilets would be needed, or about 2200 liters (581 gal). All

0.00

2000.00

4000.00

6000.00

8000.00

Septic + CW Septic +Leach

Septic +RBC

Septic +Trickling

Compost +CW

Compost +Leach

GW and Combined Systems Annualized Costs


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calculations are outlined in Appendix D, under the septic tank and composting toilet

sections.

Constructed Wetlands

The constructed wetlands receive wastewater from a pipe connected to the

septic tank. Wastewater can either flow above the existing soil, or it can flow

through the soil, such as gravel, clay, or sand. The flow of the wastewater is

relatively even, flowing across the width of the wetland. The Constructed Wetland

contains microorganisms known as periphyton that break down the pollutant in

wastewater, and much of the waste and excess concentration of nutrients are

consumed by the many plants that exist in the wetland. The purpose of the

constructed wetland is to mimic natural wetlands, and thus it is necessary to place

plants into the system. As saltwater is used from the ocean, it is necessary to use

saltwater plants such as saltmeadow hay, salt grass, sea lavender, and salt marsh

aster. The cost of just the wetlands is $435.36, while the cost of the combined septic

tank and constructed wetlands system is $1628.66. The size of the wetland is

3208.33 ft3. All calculations are listed under Appendix D Combined System

Constructed Wetland.

Leach Field

Leach fields are a secondary treatment option for wastewater, cleaning the

water after it has gone through a primary treatment option. The system generally

contains a large number of perforated pipes that leach wastewater from them into

the soil such that the microorganisms can cleanse it, but animals in the ecosystem

wont be able to reach it. The leach fields contain bacteria in the soil that remove


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dissolved organic material in the effluent. The annualized cost of the system is

$623.71, with a size of 4800 ft2. All calculations are listed under Appendix D

Combined System Leach Field.

Conclusion

After comparison of the constructed wetlands and leach field, the Alpha team

chose the constructed wetlands as the secondary treatment option for wastewater,

allowing for the entire system to be composed of a septic tank and a constructed

wetland. There were many considerations that led to this decision. As the

calculations show, the constructed wetlands is cheaper than the leach field by a cost

of $1628.66 to $1817.01, which is another good reason to use the constructed

wetlands over the leach field. The constructed wetlands also provides Appledores

inhabitants with an aesthetically pleasing piece of land and wildlife a habitat to live

in. Taking all of these considerations into account, it is clear why the septic tank and

constructed wetlands combination is better than the septic tank and leach field

system.


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System Placement

The placement of systems is dependent on existing infrastructure and the

natural characteristics of the island. The Alpha team recommends placing a Solar

Panel Field in an area that is large and open, such as the north side of Appledore

Island. These could hypothetically go anywhere there is room and direct sunlight.

Ideally, the Slow Sand Filtration would be placed in an area where the soil is mostly

sand as it requires a lot of sand to function. Further, close placement to housing and

Constructed

Wetlands

Solar Panel Field

Slow SandFiltration


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dormitories will provide fast access to drinking water for the population on the

island. Constructed Wetlands were placed very close to water in a marshy area,

necessary for water flow into the system. Placement also considered the location of

the restrooms, as it is necessary to treat the water in a timely manner without

allowing the harsh smell of the wastewater to reach the people of Appledore.

Conclusion

The most sustainable design for Appledore Island includes Solar Power for

Energy, Slow Sand Filter with Chlorination for Drinking Water, and Constructed

Wetlands with a Septic Tank for Wastewater. The Alpha Team finds solar power the

best option for energy because of its inexpensiveness and space efficiency.

Appledore currently uses solar power, making it viable to extend the infrastructure

onto more buildings or further onto the island. The next step is to increase the

production and application of the solar energy so Appledore no longer needs to use

Diesel Fuels. The Slow Sand Filter was chosen because it was the less expensive

compared to rapid sand. However, it does require a high usage of sand but it does

not backwash the water, which is important as energy demand does not increase.

Appledore must watch its water consumption as the slow sand filter cleans slowly,

and there will be less water available in comparison to other systems. As for

wastewater, Constructed Wetlands are the lease least expensive overall and

extendable. Because of their characteristics, it will provide a good habitat for

wildlife and blend in with the environment. The Constructed Wetlands are also

much smaller than the Leach fields, making it the best option for wastewater. The


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Alpha Team finds these to be the most sustainable options for Appledore moving

forward.

WORKS CITED

About Celia Thaxter's Island Garden.. (n.d). Retrieved May 5, 2015, from

http://www.sml.cornell.edu/sml_publiced_aboutthegarden.html

Advantages and Disadvantages of Biomass. Eco Home Essentials, 2015. Web. 11

May 2015.

Bach, Alan, Michelle Bowen, Paroma Chakravarty, and Sean Snow.2014 Sustainable

Engineering Report. Shoals Marine Laboratory, 2015.

Capital Cost for Electricity Plants. U.S. Energy Information Administration, April 12,

2013. Web. 11 May 2015.

Jones, Ben. What to Expect from Biomass Boiler Systems. The Green Home:

Construction and Lifestyle. Web. 11 May 2015.

The Mission of the Shoals Marine Laboratory. (n.d). Retrieved May 5, 2015, from

http://www.sml.cornell.edu/sml_welcome_mission.html

Types of Biomass Fuels. Types of Biomass Fuels. Hurst Boiler and Welding

Company, Inc., 2015. Web. 11 May 2015.


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Appendix A

Appledore Island information

The above graph (Lecture Notes 1-30 Slide 20) outlines the average generator

capacity utilization on Appledore over the course of 1 day. For a baseline, it is

assumed that the power used is 30 kW, and therefore the overall energy used per

day is 720 kWh. However, the Alpha Team aims to attain a more accurate measure

of energy used. Therefore, the graph was broken as follows:

30 kW * 12 hr + 26.25 kW * 3 hr + 21.25 kW * 6 hr = 652.5 kWh/day

Knowing the energy used per day, the amount of CO2 produced can be calculated.

. *

.

9. = 163 kg CO2/day

The rate at which energy is used can also be determined.

verage Generator Capa city Utilization over a Da y

0

10

20

30

40

50

60

10:15 AM 4:15 PM 10:15 PM 4:15 AM 10:15 AM

0%

15%

29%

44%

59%

74%

88%


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. = 27.1875 kW

Because Appledore only functions for 3 months of the year, costs, energy usage, and

other factors relying on time must keep this in consideration.

= 91.25 days 91 days

Appendix B

Energy Systems

Solar Energy

The annualized costs were calculated as follows. First, the uniformed costs:

Capital Cost = $4183/kW, Discount Rate = 0.05, Lifetime = 20 years

($4183*27.1875 kW)[ .(+.)]= $9125.61

Then the annualized costs were calculated by adding uniform and O&M Costs:

$9125.61 + ($27.75/kW/yr * 27.1875 kW) = $9,880.07

It is assumed that BP 3160 Solar Panels are used, which have a max power output of

160W, voltage of 35V, current of 4.5 amps, and a size of 31 x 63.(Lecture Slides 2-

9 Slide 22). Appledore has 5.23 Peak Sun Hours (Lecture Slides 2-9 Slide 23), or the

effective sunlight received per day. Therefore, the energy per panel per day is:

160 W * 5.23 PSH = 836.8 Wh /day / panel

Assuming the efficiency of the inverter is 0.75, and the efficiency of the battery is

0.8, the amount of energy needed to be stored is:

EPSH+ Enight =

. .

. +(. )

. .. = 1028.26 kWh

The number of panels needed are:


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*

. = 1229 panels

The area needed is:

(31 in * 63 in)*(1229 panels) = 2,399,836.5 in2= 16,665.53 ft2

The preferred angle for the panels is:

42.96 - 15 = 27.96 28

Shifting the area used by the panels to:

63 *cos(27.96) = 55.65 = Adjusted Side Length

31 * 55.65 = 1725 in2= Adjusted Area per panel

1725 in2 * 1229 panels *( )2= 14,722.4 ft2

Hydroelectric Energy



($2936*27.1875 kW)[ .(+.)]= $4372.42


$4372.42 + ($14.13/kW/yr * 27.1875 kW) = $4,756.58

Size of the basin was assumed to be 1500m x 1500m x 6m.

V = 13,500,000 m3

A = 2,250,000 m2

The channel has a length of 30m and width of 5m, having an area of 150 m2

. This

makes the velocity of fluid:

vfluid ==

*

= 4.167 m/s

Assuming the Alpha Team uses 50 turbines, each turbine will have a radius of :


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Etotal= Ptotal*

*

652500 Wh = Ptotal*

*

Ptotal= 27,187.5 W

Ptotal= nturbines* pturbines

27,187.5 W = 50 turbine * pturbines

pturbines = 543.75 W

pturbines=* Atpv

3 *efficiency

543.75 W =

r

2

(1027

)(4.167)

3

(0.4)

r = 0.108 m

Biomass Energy



($4114*27.1875 kW)

[

.

(+.)]= $8975.08


$8975.08 + ($105.63/kW/yr * 27.1875 kW) = $11,846.90

Wind Energy



($6230*27.1875 kW)[ .(+.)]= $11,018.29


$11,018.29 + ($74.00/kW/yr * 27.1875 kW) = $13,030.17


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Geothermal Energy



($6243*27.1875 kW)[ .(+.)]= $9549.39


$9549.39 + ($132/kW/yr * 27.1875 kW) = $13,138.14

Pressure of steam is calculated as stated:

1 Kb *

*

= 100,000 kPa

Appendix C

Drinking Water Treatment Systems

Chlorination

The annualized cost for chlorine were calculated.

Present cost * Chlorine (kg) = Annualized Cost

$10/kg * 3.747 kg = $37.47

Sizing for the contact tank was completed as follows:

Residual Chlorine = 1.2 mg/L

Concentration of E.Coli = 0.034 0.05 mg min/L

Concentration of Girardia = 47 150 mg min/L

Concentration = 150 mg/L = ConcC2 * time = ConcC2 * V/Q

150 = 1.2 *

.

V = 275 gal or 1041 L


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Slow Sand Filtration

The annualized costs were calculated. First, the annualized costs for the system:

Capital Cost = $100/m2, Discount Rate = 0.05, Lifetime = 15 years

($100*2.17 kW)[ .(+.)]= $20.91

Uniformized Cost + O&M Cost = Annualized Cost

$20.91 + $100.00 = $120.91

Then the annualized cost for the sand:

Capital Cost = $1/kg, Discount Rate = 0.05, Lifetime = 15 years

($1*7000 kg)[ .(+.)]= $674.40


$674.40 + $0.00 = $674.40

Then the annualized cost for the contact tank:

Capital Cost = $1/gal, Discount Rate = 0.05, Lifetime = 15 years

($1*275 gal)[ .(+.)]= $26.49


$26.49 + $0.00 = $26.49

The annualized costs were calculated by adding chlorine, system, contact tank, and

sand:

$37.47 + $120.91 + $674.40 + $26.49 = $859.26

The slow sand filter was sized as follows:

Assuming flow rate (Q) = 1.168 gal/min because demand = needed flow rate


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Assuming V = 0.05 gpm/ft2as average loading rate such peak loading rate does not

exceed 0.1 gpm/ft2

A =

=

.

. = 23.36 ft2= 2.17 m2

Amount of sand used:

Assuming depth of sand is 4 feet:

(23.36 ft2) * (4 ft) = 93.44 ft3

93.44 ft3 *,.

= 2.65 * 106cm3

Density of Sand = 2.65 g/cm3

Mass of Sand = 7000 kg

Rapid Sand Filtration



($100*0.043 m2)

[

.

(+.)]= $0.35


$0.35 + $500.00 = $500.35

Then the annualized cost for the sand:

Capital Cost = $1/kg, Discount Rate = 0.05, Lifetime = 20 years

($1*78.792 kg)[ .(+.)

]= $6.32


$6.32 + $0.00 = $6.32

Then the annualized cost for backwashing:


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Capital Cost = $4183/kW*70 GPD*0.05 kW/GPD = $14,640.5

Discount Rate = 0.05, Lifetime = 20 years

($14640.5)[ .

(+.)]= $1174.79


$1174.79 + $0.00 = $1174.79

Then the annualized cost for the contact tank:

Capital Cost = $1/gal, Discount Rate = 0.05, Lifetime = 20 years

($1*275 gal)[ .(+.)]= $22.07


$22.07 + $0.00 = $22.07

The annualized costs were calculated by adding chlorine, system, contact tank, and

sand:

$37.47 + $500.35 + $6.32 + $1174.79 + $22.07= $1,740.99

The rapid sand filter was sized as follows:

A ==

. .

= 23.36 ft2= 2.17 m2

Amount of sand used:

Assuming depth of sand is 27, or 2.25 feet:

Vsand= 1.05 ft3= 29,733 cm3

Density of Sand = 2.65 g/cm3

Mass of Sand = 78,792 g = 78.792 kg

Solar Distillation


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Capital Cost = $0.35/m2, Discount Rate = 0.05, Lifetime = 10 years

($0.35*2592.5 m2)[ .

(+.)]= $117.51


$117.51 + $500.00 = $617.51

The size of the Solar Distillation system was determined as follows:

A =.

Q =.

.

= 6366.74 L/day

E = 0.3

G =.

=

A =. .

../

= 2592.5 m2

Appendix D

Wastewater Treatment Systems

Septic Tank

The annualized cost of the septic tank was determined as follows:

Capital Cost = $3.60/gal, Discount Rate = 0.05, Lifetime = 20 years

($3.60*2400 gal)[ .(+.)]= $693.30


$693.30 + $500 = $1193.30

The size of the septic tank was determined as follows:


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V =

*

=

= 2400 gallons

Composting Toilet

The annualized cost of the composting toilet was determined as follows:

Capital Cost = $3000/unit, Discount Rate = 0.05, Lifetime = 15 years

($3000*22 units)[ .(+.)]= $6358.59


$6358.59 + $350 = $6708.59

The sizing of the toilets was completed as follows:

500 L/year urine * 0.25 years = 125 L/summer urine / person

50 L/year feces * 0.25 years = 12.5 L/ summer feces/person

160 people live on island at peak time

125 * 160 persons = 20,000 L urine

12.5

* 160 persons = 2,000 L feces

Each toilet holds 1,100 L of waste, with 22,000 L of waste

Thus number of toilets =,

/= 22 toilets

Combined System Constructed Wetland

The annualized cost of the combined constructed wetland was determined as

follows:

Capital Cost = $0.72/ft3, Discount Rate = 0.05, Lifetime = 20 years

($0.72*3208.33 ft3)[ .(+.)]= $185.36



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$185.36 + $250 = $435.36

The cost of the entire system is:

$435.36 + $1193.30 = $1628.66

Sizing for the wetlands were as follows:

Hydraulic Retention Time = 10 days

Flow rate from septic tank is 2400 gal

HRT == 10 days =

/

V = 24,000 gal *.

= 3208.33

Separated System Constructed Wetland

The annualized cost of the separate constructed wetland was determined as follows:


($0.72*2180 ft3)[ .(+.)]= $125.95


$125.95 + $250 = $375.95


$375.95 + $6708.59 = $7084.54

The sizing of the constructed wetland was completed as follows:

Assuming flow rate (Q) = 1677 gallons/day

Assuming Hydraulic Retention Time = 10 days

HRT == 10 days =

/

V = 16770 gal *.

= 2180


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Combined System Leach Field

The annualized cost of the combined leach field was determined as follows:


($0.70*4800 ft2)[ .(+.)]= $323.71


$323.71 + $300 = $623.71


$623.71 + $1193.30 = $1817.01

The sizing of the leach field was completed as follows:

Appledore Percolation rate = 36.3 min/in

Treatment Area = 2.00 ft2/gal/day

.

*

= 4800

Separate System Leach Field

The annualized cost of the separate leach field was determined as follows:


($0.70*3554 ft2)[ .(+.)]= $239.68


$239.68 + $300 = $539.68


$539.68 + $6708.59 = $7248.27

Sizing of the leach field was completed as follows:

Appledore Percolation rate = 36.3 min/in


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Treatment Area = 2.00 ft2/gal/day

Using Greywater Flow Rate of 1677 gal/day

.

*

= 3554

Rotating Biological Filter

The annualized cost of the RBC media was determined as follows:


($2.85*7360 ft2)[ .(+.)]= $1683.17


$1683.17+ $1500 = $3183.17

The annualized cost of the RBC tank was determined as follows:


($3.00*101.91 ft3)[ .(+.)]= $24.53


$24.53+ $1500 = $1524.53

The cost of the entire system is the media, tank, and septic tank:

$3183.17 + $1524.53 + $1193.30 = $5901.00

Sizing of the media is as follows:

BOD Removed = BOD5 * 0.5

441 * 0.5 = 220.5

220.5

30

= 190.5

190.5

*2400*3.785

* 2.2046* 10

-6

= 3.8


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3.8

*

.

= 7360media

Size of Tank was calculated as follows:

Assuming media of 3ft radius disk, area = 28.27 ft2

Area of a 12 ft radius disk = 113.097 ft2

. .9= 0.25 ratio

Therefore, to proportionally determine the surface area:

104,000 ft2* 0.25 = 25,996.09 ft2

Proportion of total SA to media area:

,99.9 = 3.532

Shaft length can then be determined as :

.= 7.078 ft

Volume then is determined as:

7.078 ft * 6 ft wide * 2.4 ft deep = 101.92 ft3

Trickling Filter

The annualized cost of the combined leach field was determined as follows:


($6500*1.817 m3)[ .(+.)]= $947.71


$947.71+ $1500 = $2447.71


$2447.71+ $1193.30 = $3641.00


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The sizing for the trickling filter is as follows:

2400 gal/day = 9.085 m3/day

Hydraulic Loading Rate =

= 10

=

9.

A = 0.9085 m2

V = 0.9085 m2* 2m = 1.817 m3

sustainable design for appledore island

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