The walls of your bedroom have an R value of 13 F sq.ft. hr/BTU. Your bedroom is 13 feet long and 12 feet wide with walls that are 8 ft high. On a particular day the average outside temperature is 25 degrees F. How much heat is lost through the walls by conduction on that day (in BTUs)?

Respuesta :

To solve this problem we will apply the concept of heat transfer and conduction depending on the Area, the temperature change and the thermal resistance, this can be expressed as

[tex]Q = \frac{A(HDD)}{R}[/tex]

Where,

A = Surface Area

HDD=Heating Degree Day

R = Thermal Resistance

According to the information the Area of the wall can be calculated with the given dimensions

[tex]A = 2 ((13*8) + (12*8))[/tex]

[tex]A= 400 ft^2[/tex]

Heating Degree Day would be

[tex]HDD = 65-25 = 40 \°F[/tex]

Finally the heat transferred is

[tex]Q = \frac{(400ft^2)(40 \°F)(\frac{24 hours}{1 day})}{13\frac{\° F \cdot ft^2 hr}{BTU}}[/tex]

[tex]Q = 29538.46BTU/day[/tex]

Therefore the heat that is lost through the walls by conduction on that day is 29538.46BTUs