FABE Exam 2

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Life Cycle Analysis

Assessing the economic and environmental impacts as well as energy cost associated with all the stages of a product’s life from cradle to cradle

Power

Power (W) = Energy (J) / Time (s)

Energy

Energy (J) = Power (W) * time (s)

Efficency

(Eout/Ein) * 100

Energy Density

Ed = E/A (J/m²) (Wh/m²)

Power Density

Pd = P/A (W/m²)

Primary Energy

Is the amount of energy used at the sorce (Ein)

End-Use Energy

Is the amount of energy actually consumed y the user (Eout)

Passive Solar Thermal Systems

Utilize the existing building characteristics to reduce artificial lighting and heating needs

Active Solar Thermal System

Utilize collectors (solar panels) and pump to capture solar energy and convert them into thermal energy

High Temperature Solar Applications

Electric Generation

Low Temperature Solar Applications

Space Heating, Domestic hot water

Fall/Spring Tilt

Fall/Spring Tilt = Latitude

Summer Tilt

Latitude - 15

Winter Tilt

Latitude + 15

Q =

Q = m (Kg) delta T (K) Specific Heat (J/Kg *K)

E admitted

E admitted = E solar – E reflected

E absorbed

E absorbed = E admitted – E lost

E Solar (radiation)

E Solar (radiation) = solar energy density x solar panel area

How to size up a solar system:

-  Understand the power density so you can understand the power incident (input)

-Tank vs tankless system

-  Understand how much output is in the solar panel that is needed (Po =(m/t) c T)

-   Understand Final vs Initial water

- Understand solar panel efficiency

What comes out of a Solar PV system

Current (I) and Voltage (V)

DC circuts

paralell lines

AC Circut

Sine function

Parallel Circuits

1/R123 = 1/R1 + 1/R2 + 1/R3= 3/R123 —> R123

Series Circuts

R1 + R2 = R12

Battery’s

Et = 10V + 5V + 5V = 20

Current =

I = Volts/Amps

Power Dissipated In a Load

R1 load disipated = Amps/R1 omls

Types of Decentralized Systems

Grid Connected, Direct Coupled, Stand Alone

Grid connected Systems

Solar Systems that connect to the grid

Direct Coupled

Solar Pannels are directly connected to the load, doesnt work at night

Stand Alone

Solar systems connected to battery

Asmuth Angle

how far the sun deviates from the southern sky (from west is 90 degrees, south is 0 degrees)

Y axis on a Solar shart

Altitude of the sun

X Axis on the solar chart

Hours (Time)

Passive Heating Mehtods

Direct Gain, Indirect Gain, Isolated Gain, Overhand

Overhang Variables: O

O = Overhang/ Length

Overhang Variables: G

Height of Windoq

Overhang Variables: H

Distance between overhand and window

Overhang Variables: S

Angle of the summer sun on Azmuth = 0 on that day

Overhang Variables: W

Angle of the summer sun on Azimuth = 0 on that day

Height of overhang =

H = O * Tan (W)

Overhang =

O = G /[tan (S) - tan(W)]

Bioenergy

Energy produced from biomass and biowaste

Biomass or Biowawste

any substance contaning Carbon (C) and hydrogen (H) like hydrocarbons (C, H, and O)

Important factors of Biomass

Crop yield, Energy Content, Emissions, Energy Balance

Net energy Gain

Eo - Eop

Energy Balance

Eo:Eop

Bioenergy Sources

Biomass, Food crop, Non food crop

Thermo-chemical process

its a process that involves the use of head and chemical reaction to conver biomass into energy

Gassification

The incomplete combustion of biomass that produces synthetic gases. Biomass is reduced to charcoal, which then reacts with CO2 and H2O to turn into Hydrogen, carbon monoxide and methane.

Reaction of Gassification

Charcoal + H2O + CO2 = CH4, H2, CO

% of land in US grows Crops, % goes to cattle

52% of land in the US grows crops. 67% of that goes to feed cattle

% of fertilizers that run off into streams

65%

Food Security

When all people, at all times, have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for and active and healthy life

Deserification

the process by which fertile land becomes desert, typically as a result of drought, deforestation, or inappropriate agriculture.

List 3 potential solutions to desertification

Cover Crops, Agroforestry, slower source of water flow

How to prevent or reverse soil erosion

work with local environment, species and people

3 types of alternate food production

Community gardens, Hydroponics, Aquaponics

List 3 methods of regenerative agriculture

change in grazing patterns, agrforesty, biological imputs in cropping

Describe regenerative grazing system

Grazing in a regenerative system means that livestock graze for a short time in one area, then moves to a different area to graze to allow the first area to regenerate. This cycle is continued over different patches of land.

How much money could farmers save by regenerative agriculture

800,000 - 500,000

name 2 ways to maintain soil health

Cover crops, compost tea

How does regenerative agriculture help with global warming

absorbs excess carbon from the atmosphere into the soil

how can people connect with the regenerative agriculture movement

supporting farmers markets or buying directly from eco-friendly farms. They could also start growing their own food.W

when did the dust bowl happen

1930s

at the end of the dust bowl how many acers of cropland were ruined

200 Million

what percentage of carbon do plants send their roots

40%

how much of our land is desertifying

2/3

define biosequestration

the storage and removal of carbon from the atmosphere by photosynthetic plants or bacteria

Define draw down

the removal of carbon dioxide from the atmosphere

COP21

The UN vlimate summit in paris

who did not sign on COP21 pledge

USA, India, China

for every 1% increase in organic matter, acre of no-till soil draws down ____ more tons of carbon

10

Standard Testing Conditions

T = 25 C, Power density = 1000W/m², AM =1.5

Short Circuts

Current = MAX Voltage = 0

Open Circut

Voltage = MAX Current = 0

Power equals 

Power = Current (I) * Voltage (V)

When do you get max power

Where SC current and Voc voltage intersect

PV Cell Structure: Crystalline

e- have very constant path

PV Cell Structure: Poly-Crystaline

e- has defined path, but has electron traps

PV Cell Structure: Amorphous

e- has no defined path

Series increases

Voltage

Parallel increases

Current

Anti-islanding

the inverter cannot operate alone as an island of power

Voltage

Electrical Pressure

Current

Electrical Flow

Power

Rate at which electricity is usedEne

Energy

Amount of electricity used over time to perform work or generate heat.