Question

A room contains four single-pane windows of size 5 ft by 2.5 ft. The thickness of the glass is 1/4 in. If the inside glass surface is at 60°F and the outside surface is at 30°F, estimate the heat loss through the windows 0HT

Answer 1

Step-by-step explanation:

The given data is as follows.

Area =
`5 ft * 2.5 ft` = 12.5
`ft^(2)`

L = 0.25 in = 0.0208 ft (as 1 inch = 0.0833 ft)

`T_(s, in) = 60^(o)F`,
`T_(s, out) = 30^(o)F`

k (thermal conductivity) = 0.8
`Btu/hr-ft-^(o)F`

Formula to calculate the heat loss will be as follows.

Q =
`k * A * (T_(s, in) - T_(s, out))/(L)`

Putting the given values into the above formula as follows.

Q =
`k * A * (T_(s, in) - T_(s, out))/(L)`

=
`0.8 Btu/hr-ft-^(o)F * 12.5 ft^(2) * (60^(o)F - 30^(o)F)/(0.0208 ft)`

= 14285.7 Btu/hr

So,
`Q_(net) = 4Q`

=
`4 * 14285.7`

= 57142.8 Btu/hr

Thus, we can conclude that heat loss through the windows is 57142.8 Btu/hr.