Nine old 12 ft 2 windows with U = 1.2 Btu h ⋅ ft 2 ⋅ ° F were replaced with new windows having U = 0.3 Btu h ⋅ ft 2 ⋅ ° F . Calculate the energy savings on a day during a 5 hour period, when T in = 68 ° F , T outside = 10 ° F .

Question

Still sussing out bartleby?

Answer 1

BuyFind

Engineering Fundamentals: An Intro...

5th Edition

Saeed Moaveni

Publisher: Cengage Learning

ISBN: 9781305084766

Solutions

Chapter

Section

Answer 2

BuyFind

Engineering Fundamentals: An Intro...

5th Edition

Saeed Moaveni

Publisher: Cengage Learning

ISBN: 9781305084766

Solutions

Chapter

Section

Answer 3

Solutions

Chapter

Section

Answer 4

Chapter

Section

Answer 5

To determine

Find the energy saving for the period of five hours.

Explanation of Solution

Given data:

The U-factor for old windows, Uold=1.2 Btuh⋅ft2⋅°F.

The U-factor for new windows, Unew=0.3 Btuh⋅ft2⋅°F.

Area of the windows, A=12 ft2.

Inside temperature, Tin=68 °F.

Outside temperature, Toutside=10 °F.

Formula used:

The formula for the heat loss through the window,

q=UA(Tin−Toutside) (1)

Here,

U is the U-factor of the windows,

A is the surface area of the windows,

Tin is the inside temperature of windows,

Toutside is the outside air temperature,

Calculation:

Substitute 1.2 Btuh⋅ft2⋅°F for U, 12 ft2 for A, 68 °F for Tin, and 10 °F for Toutside in equation (1) to find heat loss through one old window (qold),

qold=(1.2 Btuh⋅ft2⋅°F)(12 ft2)(68 °F−10 °F)=(1.2 Btuh⋅ft2⋅°F)(12 ft2)(58 °F)=(1.2×12×58) Btuhqold=835.2 Btuh

The heat loss through one old window for 5 hours is,

qold=(835.2 Btuh)(5 h)=(835.2×5) Btuqold=4176 Btu

Hence the heat loss through 9 old windows will be,

qold=9×4176 Btuqold=37584 Btu (1)

Substitute 0

Nine old 12 ft 2 windows with U = 1.2 Btu h ⋅ ft 2 ⋅ ° F were replaced with new windows having U = 0.3 Btu h ⋅ ft 2 ⋅ ° F . Calculate the energy savings on a day during a 5 hour period, when T in = 68 ° F , T outside = 10 ° F .

Engineering Fundamentals: An Intro...

Solutions

Engineering Fundamentals: An Intro...

Nine old 12 ft² windows with U = 1.2 Btu h ⋅ ft 2 ⋅ ° F were replaced with new windows having U = 0.3 Btu h ⋅ ft 2 ⋅ ° F . Calculate the energy savings on a day during a 5 hour period, when T in = 68 ° F , T outside = 10 ° F .

Explanation of Solution

Still sussing out bartleby?

The Solution to Your Study Problems

Chapter 11 Solutions

Additional Engineering Textbook Solutions

Nine old 12 ft 2 windows with U = 1.2 Btu h ⋅ ft 2 ⋅ ° F were replaced with new windows having U = 0.3 Btu h ⋅ ft 2 ⋅ ° F . Calculate the energy savings on a day during a 5 hour period, when T in = 68 ° F , T outside = 10 ° F .

Engineering Fundamentals: An Intro...

Solutions

Engineering Fundamentals: An Intro...