Solar Cooker Stand Phase 1--brainstorming and project goals

For our final project, Ananya and I are working on improving and refining the existing solar cooker stand for our community partners in Nicaragua. Currently the problems are that the design is expensive, inefficient, and difficult to assemble.

Project Goals:

-Make a smaller, more efficient stand

-Use materials readily available in community

-Make it mobile, height adjustable and wind-proof

-It should be easy to assemble and easy to teach women in the community how to assemble

-Solar cooker should be secured to stand

Problems to consider:

Metal is too expensive, lumber needs to weatherproofed/treated.

-Could we use plastic? PVC piping structure

How can we secure the sliding cooktop surface?

-magnets? what is the solar cooker made out of?

- notches? what type of notch is the simplest to cut? what type of notch is the most secure?

Questions for community partners:

What material is the solar cooker made out of?

How large is the solar cooker?

How much does it weigh?

Does it need to be tilted?

Does it need to be height adjustable?

What tools do you have to use at your disposal?

What tools are available in the community?

What materials are readily available? (ie. plastic trays, PVC, lumber, wood, metal, etc)

existing stand:

My Energy Consumption Over Three Days

As an exercise in estimation and in looking at energy consumption, I monitored my activities over three days. One of those days I went into Boston using bus and subway. I also did laundry and showered. Here is the break down of my estimations:

Electronics

Phone Charger (20 hours)

Laptop Charger (20 hours)

Speaker (10 hours)

Lights

-in dorm--50 hours

-classrooms/public spaces 50 hours (split with other classmates using it)

Heating/Cooling

shower water (1 hour)

Hot water boiler (2 hours)

AC/Heat (72+ hours)

Refrigeration (72 hours/number of students)

Oven heat (20 hours/number of students)

Washing Machine/Dryer: 4 hours

Fossil Fuel

Peter pan bus (2.5 hours)+5 trains (1.5 hours)

Unit: Joules

J/s=Watts

To find Joules: (Watts*sec)/# of people using it

Wattage estimation:

Electronics:

phone charger: 50W/hour-->20 hours-->72000 seconds

50W*72000s=3600000 Joules

Laptop charger: 100W/hour-->20 hours-->72000 sec

100W*72000s=7200000 Joules

Speaker: 20 W/Hour-->10 hours-->36000 sec

20W*36000s=720000 Joules

TOTAL: 11520000 Joules

Lights

Dorm: 60W-->50 hours-->180000 sec (split between 3 people)

(60W*180000s)/3=3600000 Joules

Classroom 60W*15000 light bulbs-->50 hours→ 180000 (split between 1000 people)

(60W*15000bulbs*180000s)/1000=162000000 Joules

TOTAL:165600000 Joules

Heating cooling:

Shower/water heater: 20,000 W/hour-->1 hour-->3600 sec

20,000W*3600s=72000000 Joules

Personal hot water boiler: 500 W/hour-->2 hour-->7200 sec

500W*7200s=3600000 Joules

AC/Heating: 40,000 W/hour-->72 hour-->259200 sec (split between 1000 people)

(40,000W*259200s)/1000= 10368000 Joules

Refrigeration: 700W/Hour-->72 hours-->259200 sec (split between 500 people)

(700W*259200s)/500=362880 Joules

Oven Heat:3000W/hour-->20 hours→ 72000 sec (split between 500 people)

(3000W*72000s)/500= 432000 Joules

Washing/Drying: 3000W/Hour→ 4 hours→ 14400sec

3000W*14400s=43200000 Joules

TOTAL: 129962880

Transportation

Peter Pan Bus (fossil fuel): 4000W/hour→ 9000sec (split between 50 people)

(4000W*9000s)/50=720000 Joules

Subway trains: 70,000W/hour→ 1.5 hours-->5400sec (split between 2000 people)

(70,000W*5400s)/2000=189000 Joules

TOTAL: 909000

TOTAL ENERGY CONSUMPTION OF ALL CATEGORIES:

307991880 Joules over 3 days (3x10^8 joules)

Power Estimations

Ways to represent Power:

Power is represented by Joules/second or in Watts.

Power=Force*Velocity

Power=IV=V^2/R=I^2(R)

Estimate the power required for typical objects:

Light:

• Assume LED bulb: 3.4 V, .02A
• P=IV, P=3.4V*.02A
• Power=.068 Watts

TV:

• assume power outlet 130 V
• Use LED with .02 Amps and 3.4 Volts
• Use proportionality: 3.4V/130V=.02A/xA
• Amps: .76A
• P=IV, Power=.76A(130V)--> 99.41 Watts

Computer:

• assume power outlet 130V
• Uses LED with .02 Amps and 3.4 Volts
• Use proportionality: 3.4V/130V=.02A/xA
• Amps: .76A
• P=IV, Power=.76A(130V)--> 99.41 Watts (same as TV)

Car:

• J=kg(m/s^2)
• Say car weighs 2000 kg and is traveling at 26m/s^2
• J=2000kg(26m/s^2)==50,000 Joules
• Assume it travels for 1 second→ 50,000 Watts

Motorcycle:

• J=kg(m/s^2)
• say motorcycle weighs 900kg and is traveling at 26m/s^2 for 1 second
• J=(900kg(26m/s^2))/1= 23400 Watts

Fridge:

• Fridge uses more power than a normal outlet probably around 300 V.
• use bulb inside of fridge to determine power?
• 3.4 V LED, .02 Amp
• use proportionality: 3.4V/300V=.02A/xA
• Amps=1.76A
• P=IV, Power=1.76A(300V) → 529.41 Watts

Oven:

• uses more power than normal outlet--around 300V
• uses bulb inside (count two bulbs for heating from bottom and top)
• (see proportionality used in fridge problem and multiply by 2):
• 1.76A*2= 3.52A
• P=IV, Power=3.52A(300V)=1056 Watts

Radio:

• battery operated radio running on 9V battery
• estimate is uses more amps than LED--about 10 amps
• 9V*10A=90 Watts

In class work on biodigestors

See the research conducted by me and Ananya in class today by clicking here.

Thanks!

Stove Project

Cardboard Models

This week we were tasked at looking at new ways to design a coal burning stove. After looking at some considerations such as efficiency, cost, safety, insulation, and adaptability we split into groups to brainstorm potential stove designs. My group knew we wanted to safety to be a number one priority so we focused mostly on a system of ventilation, as well as considered a sunken cook-top to prevent burns and spills. We created a stove with an inner chamber for the fuel to rest and ran a chimney out of that chamber. Around that chamber we wanted an insulating material such as clay that is cheap and effective. The cook surface rests directly above the chamber. There is two doors (an outer door and an inner door) that you use to access the fuel. The two doors provide a safer chamber. The downside of our design is that we didn't put enough consideration into the air flow to get to the heat. In talking with the class we thought making the bottom of the stove more of a grate so that air could flow in and up through the bottom would be the best next step in the prototyping. In making our cardboard model I feel more familiar with the general parts of the cook-stove and I'm interested to delve further into exploration to the best coal burning stove.

Estimating Weight to Power LED Bulb for 30 Minutes

Assumptions:

-LED= .02Amps

-Gravity is 9.8m/s^2

-Not accounting for wind or other resistance

- Dropping weight from 2 meters

-Powered by 9V battery

1. How many Joules to needed to power for 30 minutes

Watts= J/s

.02A*9V=.18 Watts

.18W=J/(30min*60sec)

.18W=J/1800s

J=324

2. How much weight to create 324 J work

J=kg(m/s^2)

324=mass((9.8m/s^2)*2m)

mass=16.5kg

Time Management Reflection

This past week we had two substantial projects and subsequent blog posts all due on the same day. There are really two scenarios of how it could have gone--the projects could have been spaced out over no time with out a lot of stress in trying to complete before the deadline...OR there could have been a lot of last minute stress in trying to finish an unreasonable amount all at once. I would say I attempted to space out the projects and was very successful in getting the sharps project done in time but the lantern proved much more difficult. Working in a group for the sharps container made it easier to be more accountable to sticking to a good schedule. We finished that in a few out of class sessions. The lantern I unfortunately left until a little bit late to get started on. It was a complete stay-up-all-night cram to finish but I wouldn't say it didn't come with some stress. Next time, I'd really want to aim at getting the physical project started much sooner because I spent too much time visualizing without realizing that building something takes a lot more time than you think. The trial and error and adjustments that need to get made are plentiful and deserve several long out of class sessions spaced out over time to get a quality finished product.