Summation of Options & Recommendation

The above is a bare bones summary of this project and a side to side comparison of the options that were studied.

[1] “Student Group Aims to Electrify Sports Center with Bicycles.” Internet: http://indianapublicmedia.org/news/student-group-aims-electrify-sports-center-bicycles-22350/, [5 June 2012].

[2] “Working Bikes.” Internet: http://workingbikes.org/node/3445, [8 May 2012].

Week 9

This has been the final week of the project and the group has been working on putting together a final report and presentation. In order to sum up the project, the group has compiled all of the various data and performed cost analyses to create some conclusions. Using the bicycle to generate power has been deemed inefficient as it would not generate enough power to run the lights, satellite internet, and charge batteries, which were the uses preferred by the wildlife center. It would take 15-24 hours a day to generate  enough power for this. It was been estimated that the bicycle might be in use for 4-6 hours each day. This would produce 0.332 to 0.498 kWh of energy every day. It was previously calculated that for every litre of gas, 1.88 kWh of energy are produced. As 1 litre of gas costs $1, $1 provides 5.3 kWh of energy. According to these calculations, using the bicycle for 4-6 hours every day would amount to saving 6.2 to 9.3 cents a day. This amounts to an average of 7.75 cents a day [(6.2+9.3)/2]. Assuming the bicycle is used every day, it would take 15,133.5 days to gain back the cost of the bicycle, which is approximately 41.5 years.

Using the bicycle powered water pump and storing energy in batteries are the recommended course of action for the Bioko wildlife center. 

The water pump would be able to 5-10 gallons of water every minute to an altitude of 30 meters. The water tank at the wildlife center holds 300 gallons, however they do not use the full amount every day. Regardless, it would only take 30-60 minutes each day to completely fill the water tank.

The wildlife center currently uses 5-6 liters of fuel every day. Each liter of fuel creates 1.88 kWh of energy, which amounts to 9.4 to 11.28 kWh a day. According to the energy calculations, the center only uses 3.34 kWh each day, therefore wasting 6.06 to 7.94 kWh each day. By using the batteries to store the energy produced by the generator, the center would be able to save this wasted energy. As the generator is run for 4 hours each day, it uses 1.375 liters of fuel each hour and creates about 2.585 kWh of energy every hour. If the center only needs 3.34 kWh of power each day, this would cost about $1.8 in fuel and the generator would only need to be run for 0.705 hours each day. 
The center could also chose to run the generator for longer, but not every day. This would save the center $3.2-4.2 each day, amounting to $1168-1533 each year. 

Week 8

The group met with Professor Gallagher on Wednesday, May 24, to discuss how the project has progressed. All team members have made good progress on their individual tasks. A more accurate kWh estimation was calculated using the emailed information from Andrew Fertig. Janet was able to determine a more accurate evaluation as to how much water the bicycle powered water pump would be able to move. This account depends upon the height of the tank from the ground. Jon was able to use the calculated energy needs of the compound to determine the number of batteries needed to store the necessary energy. Details on this progress will be included in future posts.

It was beneficial to meet with Professor Gallagher as it helped the group make sure that the project was progressing as expected. Gallagher expressed no main concerns about the project, just mentioned a few small details such as being extremely detailed in the report, almost to the point of redundancy, and making sure to properly obtain and describe all references. The final report was also discussed and Gallagher gave a few recommendations as to how to set it up.

Generator Calculations

       New information provided by the graduate students at the field station can be used to estimate the energy production of the generator. The amount of gasoline burned in the generator corresponds to total energy created based on accepted values for the energy density of gasoline. One liter of gasoline contains 34 megajoules of energy, stored in the chemical bonds of each hydrocarbon molecule [1]. The energy produced is also affected by the amount of energy lost in the form of heat, unburned fuel, exhaust, friction, and engine cooling. A typical engine will run at around 25 to 30 percent efficiency [2]. Generators, in their conversion of mechanical energy to electrical, operate at around 60-70 percent. For the calculations, it can be assumed that the generator is 20% efficient in converting the chemical energy in gasoline to electrical.

Energy produced by the generator:

Assume: 5-6 liters are consumed, 34MJ/L of gasoline (energy density), 20% efficiency

Max:

20%*34MJ/L*6L(1hr/3600s)=11.3kWh

Min:

20%*34MJ/L*5L(1hr/3600s)=9.4kWh

These values,11.3 and 9.4kWh, are the upper and lower bounds of the energy produced by the generator in a period of usage, burning 5 to 6 liters of fuel. While this is the energy produced, this is not the amount of energy typically consumed at the station. The difference is lost in the form of heat, unbruned fuel, and electrical resistance. The purpose of the battery storage system would be to store all the energy produced by the generator at one time in the batteries. Then this energy could be utilized later on more efficiently.

[1] "Energy in natural processes and human consumption" Internet: http://www.ocean.washington.edu/courses/envir215/energynumbers.pdf, [13 May 2012].
[2] "Fuel Economy: Where the fuel goes" Internet: http://www.fueleconomy.gov/feg/atv.shtml, [15 May 2012].

Updated Daily kWh Usage

The group was able to contact several people who have been at the Bioko field station in order to obtain some necessary information about daily energy use, water usage, generator specifics, and so on. Using some of this information, some more accurate daily kWh usage was able to be determined.

The estimations of energy consumption are based on the follow specifications:


Lights
It was reported that there are 5-12 lights on at one time, including a large outdoor flood light. These lights are generic types of various wattage [1]. The following numbers were calculating assuming CFL bulbs. While it's unclear what types of bulbs the center is using, the following numbers could easily be obtained by switching to CFL bulbs. Furthermore, it would likely be beneficial if the center used CFL bulbs as these bulbs are more energy efficient. The flood light used in these calculations is an 60 watt LED flood light [2]. The calculations assume that the lights are on for four hours, except there is one light that is on all night, for approximately 12 hours [3].
The CFL bulbs use 16 watt hours of energy [4] and the LED flood light uses 15 watt hours [2]. Therefore, the center is using approximately 0.244 to 0.356 kWh a day. 

Laptops
The laptops are charged on a daily basis [1] and it has been assumed that there are around five people at the station at one time. This is double the prior estimate, which means that charging laptops would use 0.65 kWh a day. An additional 0.051 kWh a day is used to charge cameras, cellphones, and other small electronic devices. This amounts to 0.701 kWh a day. 


Internet
The internet modem used at the wildlife center is 110 volts [1]. The average 110 volt internet modem uses about 20 watt hours, which amounts to 0.08 kWh a day. 


These three categories are the sources that were originally intended to be powered by a bicycle. According to these new calculations, the center would need to produce 1.025 to 1.137 kWh a day. It was previously determined that 0.25 kWh could be produced per hour of cycling on the bicycle. It is still unknown exactly how much energy would be lost during the conversion process, but for these calculations the energy loss has been calculated in at 50%. Therefore, only 0.125 kWh would be produced an hour. As a result, it would take 8.2 to 9.1 hours of cycling each each to produce the necessary amount of energy.

In addition to the above categories, the center also has a TV, printer, and refrigerator [1]. The specs for these appliances are unknown, so averages were used for the kWh calculations. An LCD TV uses 111 watt hours [5]. If the TV is used for four hours a day, this uses 0.444 kWh a day. An average laser printer uses 460 watt hours [6]. If the printer is on for 5 minutes a day, this amounts to 0.38 kWh a day. A 12 cubic foot refrigerator uses 240 watt hours [7]. If the refrigerator is run for 4 hours a day, it uses 0.96 kWh a day. This amounts to 1.784 kWh a day. 


Therefore, the total daily energy usage is 2.809 to 2.921 kWh. 


[1] Fertig, A. (2012, May 14). Available e-mail: Andrew.Fertig@gmail.com Message: Field Station Specs
[2] "Best Home LED Lighting." Internet: http://www.besthomeledlighting.com/led_floodlight, [16 May 2012].
[3] "Time Zone Guide: Equatorial Guinea." Internet: http://timezoneguide.com/sunrise-sunset-EquatorialGuinea-Malabo.html, [16 May 2012].
[4] "Energy Use Calculator." Internet: http://www.thesolarguide.com/calc.aspx, [1 May 2012].
[5] "TV Power Efficiency." Internet: http://reviews.cnet.com/green-tech/tv-power-efficiency/, [16 May 2012].
[6] "Computer Energy Usage Facts." Internet: http://computing.fs.cornell.edu/Sustainable/fsit_facts.cfm, [16 May 2012].
[7] "Watt Uses Watt." Internet: http://www.diversepower.com/watt_uses_watt.php, [16 May 2012].

Estimated Daily kWh Usage

In order to determine whether or not the bike is a feasible and worthwhile method of generating electricity for the field station, the number of kWh used at the center must be determined. The team has contacted several people who have visited the station in order to gather information about the specific appliances used, such as the type and magnitude of use. No specific information about the appliances and their use has been given at this point, therefore the general approximations of the station's kWh usage has been done through researching the appliances.

The possible uses for bicycle-generated electricity are lighting, charging laptops, running the satellite internet, and pumping water. It's unlikely that the bicycle would be able to sustain the necessary energy to run the water pump, therefore the kWh numbers only concern light usage, satellite Internet, and charging batteries for laptops and cameras. The group is assuming limited usage of all these appliances. Even if this does not reflect the currant usage, it represents possible usage if the people at the station are careful about the amount of electricity and water that they use. It's also important to the note that the group has discovered an alternate method to pump water using the bicycle, but that doesn't necessarily take into consideration the kWh. Here, the bicycle would directly pump the water.

The elevated water tank holds 300 gallons of water, however the station does not use 300 gallons of water  per day. The number of gallons used daily has been estimated. Using the amount of gallons pumped per minute (approximately 5-10 gallon a minute), it can be determined how long one would need to cycle for in order to move the water needed for a set period of time.

Water Usage:
The water usage estimates take into account the following uses: showers, hand-washing, washing dishes, and brushing teeth. We are currently trying to get information regarding any other uses, such as drinking and washing clothes. The following approximations are  assuming that there are five people at the center.

Showering: Showering uses 2.5 gallons a minute if a water-saving fixture is incorporated[2]. Assuming 5-10 minute showers, this would use 62.5 to 125 gallons a day.
Handwashing: Assuming that one washes their hands 4 times a day for 45 seconds each washing (remember that they are gone for the majority of the day), hand washing would use about 22.5-37.5 gallons a day. This is considering that a sink with a water saving fixture uses 1.5 to 2.5 gallons a minute[2].
Brushing Teeth: If each person at the center brushes their teeth twice a day and turns off the water while brushing, this would use 7.5-12.5 gallons a day, again assuming a sink with a water saving fixture.
Washing Dishes: It was estimated that washing dishes each day would take ten minutes, thereby using 15-25 gallons a day, again assuming the sink has a water saving fixture.

According to these calculations, the current daily water usage would be 112.5 to 205 gallons a day. If the pump moves 5-10 gallons a minute, a person would need to bicycle for anywhere from 11.5 minutes to 41 minutes.

Satellite Internet:
The estimates for the satellite internet are rough because the wattage of the modem greatly differs amongst various models and the ages of said models. An estimate of the wattage was determined to be about 50 watts after finding multiple reports of 30 watt, 45 watt, 65 watt, and 85 watt models. Currently, the generator runs the Internet for four hours an evening. This would amount to 0.2 kWh a day. If the users were able to consolidate their usage into two hours, this would amount to 0.1 kWh a day.


Lighting: 
There are six rooms at the wildlife center. It was previously assumed that there are two lightbulbs in each room and that each bulb would be used for 4 hours a day -- the same length of time that the generator was running. However, with only five people, it's unlikely that usage would be this high. It was then estimated that only half the lights would be on at one time, and perhaps for only three hours. At this point in time, it is not known what type of lightbulbs the station uses, but the following estimates are for compact fluorescent lights (CFLs). Most likely, if the station is not using CFLs, we will recommend that they change to this type. 60 watt CFLs have an estimated wattage of 16 watt hours[1]. Using these numbers, it's estimated that the lights will use 0.0288-0.0384 kWh a day. 0.0288 kWh refers to usage for three hours and 0.0384 kWh to four hours a day.

Charging Batteries:
Laptops: In order to determine how much energy would be needed to charge laptops, average battery life, average charging time, and wattage needed to be determined. All of these aspects are highly variable depending upon laptop brand, size, age, etc. However, some averages were determined in order to calculate an approximate amount of energy used. The average battery life was estimated to be 3-4 hours, although it is often longer if the computers are run on power saving settings or are newer models. It is currently unknown whether the laptops are used during the day, so it is assumed that they are only used in the evening. Using that assumption, it is estimated that each laptop would need to be charged every other day.  It takes approximately two hours to charge a laptop if the appliance is turned off while it is charging. Finally, the average laptop wattage was determined to be approximately 65 watts[1]. Using this information, charging laptop would require 0.325 kWh a day. 
Cameras: Basic digital handheld cameras are normally 25-50 watts and it takes approximately one hour to charge a camera battery. It was assumed that at most, a camera battery would need to be charged once a week. Therefore, charging camera batteries would require 0.017 kWh a day. 


Using these estimates, the approximate number of kWh for one day would be 0.4804 kWh. This amounts to 3.3628 kWh a week.

Following these estimates, the group will begin determining more accurate numbers as to how much energy could be created using a bicycle and how much energy would be lost during the storage process. Using this information, it will be able to be determined how many hours a day the bicycle will need to be used in order to generate enough energy to run the aforementioned appliances.

[1] "Energy Use Calculator." Internet: http://www.thesolarguide.com/calc.aspx, [1 May 2012].
[2] "A Water Resource - Water Use Chart." Internet: http://fi.edu/guide/schutte/howmuch.html, [6 May 2012].

Week 6

Introduction:
         One way to reduce the energy usage at station would be a battery bank. The batteries would be charged by the generator and serve as the power source for as long as they lasted. Another  method would utilize a human powered water pump to replace the old gas pump. These two systems would be more efficient and save energy overall.


Battery Storage Component:

        One way to increase efficiency at the station would be to store the excess energy produced by the generator while its running. The generator will typically produce more power than is needed when it is in use. This excess energy is lost to heat, noise or the incomplete combustion of the fuel. A bank of batteries could be used to  store all the power produced by the generator and then used for electricity later on. 

       The system would take the electricity created by the gas generator and initially step it down with a charge regulator. This would produce a voltage above 12 volts but not exceeding 14, the safest maximum before overheating and failure. A voltage below 12 volts would cause a back-flow of electricity so the regulator keeps the voltage in this range. The voltage would charge the batteries in a predictable amount of time dependent on the output of the generator. Once the batteries were fully charged, an invertor would step the voltage up form a 12 volt DC current to 120 volt AC current. Most appliances run on 120 volts so the battery bank could be used to charge laptop, camera and phone batteries as well as running lights and an internet modem. [1]
          Figure 1 shows the energy flow of the battery system, as power moves from the generator, is stepped down by the regulator, stored in the batteries, stepped up by the inverter and used by appliances.

Figure 1: Flow Chart for Battery System

Bicycle Water Pump Component:

           To pump water from the lower reservoir into the higher one the field station currently uses gas generator. The higher reservoir is above all facets and piping which allows gravity to do work and create a water pressure for when being used in the instances of showering or toilet flushing. Figure 2 shows a depiction of how present water pumping system. 

Figure 2: Current Water Pumping System

The bicycle pump will replace the electric pump that utilizes the gas generator for power. This will minimize gas consumption and in turn reduce cost. Further cost analysis will give numerical estimates. The bicycle water pump system works by taking apart an old bike locking it into place, either with bolts or cementing it to the ground. The gear would then attach to pulley system that is created with the removed wheels. A wire with stoppers is latched to the pulley which rotates and traps the water from the lower reservoir into PVC (polyvinyl-chloride) plumbing tubes that dumps into the higher reservoir.

Figure 3: Proposed Water Pump System [2]

Work Cited

[1] "Basic Tutorial: Storage Batteries" Internet: http://www.freesunpower.com/batteries.php, [8 May 2012].

[2] “Working Bikes.” Internet: http://workingbikes.org/node/3445, [8 May 2012].