- #1

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## Homework Statement

Fill in the empty columns of the following table:

## Homework Equations

y = ΔE x c

P = ΔE/Δt

ΔE = Y/ Δt

## The Attempt at a Solution

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__Part d) Yearly energy cost:__

Use Y=ΔE x c

Refrigerator, top freezer:

Y = (448 kWh/yr) ($ 0.06)

Y = $ 26. 88/yr

Refrigerator, bottom freezer:

Y = (393 kWh/yr) ($ 0.06)

Y = $ 23.58/yr

Upright freezer:

Y = (420 kWh/yr) ($ 0.06)

Y= $ 25.20/yr

Chest freezer:

Y = (362 kWh/yr) ($ 0.06)

Y = $21.72/yr

Top-loading clothes washer:

Y = (301 kWh/yr) ($ 0.06)

Y = $ 18.06 / yr

Front-loading clothes washer:

Y =(153 kWh/yr) ($ 0.06)

Y = $ 9.18/yr

__Part e) Energy used in one week:__

Use ΔE = Y/Δt

Refrigerator, top freezer:

ΔE = 448 kWh /yr / 52 weeks

= 8.62 kWh/week

Refrigerator, bottom freezer:

ΔE = 393 kWh/yr / 52 weeks

= 7.56 kWh/week

Upright freezer:

ΔE = 420 kWh/yr / 52 weeks

= 8.08 kWh/week

Chest freezer:

ΔE = 362 kWh/yr / 52 weeks

= 6.96 kWh/ week

Top- loading clothes washer:

ΔE = 301 kWh/yr / 52 weeks

= 5.79 kWh/ week

Front-loading clothes washer:

ΔE = 153 kWh/yr / 52 weeks

= 2.9 kWh/week

__Part f) Estimate of hours in use per week:__

Okay, so for all the refrigerators and freezers, I estimated the hours of use to be 168 hours, since I assumed these appliances are being used all day for the entire week. ( I am not sure if that is correct)

For the washers, I estimated the hours per week to be 5 hours.

Can someone please tell me if my estimate is correct, or do I need to put a different amount of hours for each appliance?

__Here is part g)__using my estimate of hours per week from part f)

Use P = ΔE/ Δt

Refrigerator, top freezer:

P = 8.62 kWh/ week / 168 hrs/week

= 0.05 kW or 50 W

Refrigerator, bottom freezer:

P = 7.56 kWh /week /168 hrs/week

= 0.045 kW or 45 W

Upright freezer:

P = 8.08 kWh/week / 168 hrs/week

= 0.048 kW or 48 W

Chest freezer:

P = 6.69 kWh/week / 168 hrs/week

= 0.041 kW or 41 W

Top-loading clothes washer :

P = 5.79 kWh /week / 5 hrs/week

= 1.158 kW or 1158 W

Front-loading clothes washer:

P = 2.9 kWh /week / 5 hrs/ week

= 0.58 kW or 580 W

Is my process and answer correct?