Questions: Use the Sensible Heat Formula to determine the heating system capacity of the following system. CFM: 2500 Return air DB: 68 degrees Fahrenheit Supply air DB: 56 degrees Fahrenheit 32,400 BTU 27,778 BTU 21,600 BTU 18,519 BTU

Solution Steps

The sensible heat formula is used to calculate the heating or cooling capacity of a system. It is given by: \[ \text{Sensible Heat} = 1.08 \times \text{CFM} \times (\text{Return Air DB} - \text{Supply Air DB}) \] where:

• CFM is the airflow in cubic feet per minute.
• Return Air DB is the dry-bulb temperature of the return air.
• Supply Air DB is the dry-bulb temperature of the supply air.

Substitute the given values into the formula:

• CFM = 2500
• Return Air DB = 68°F
• Supply Air DB = 56°F

\[ \text{Sensible Heat} = 1.08 \times 2500 \times (68 - 56) \]

Calculate the difference between the return air and supply air temperatures: \[ 68 - 56 = 12 \]

Substitute the temperature difference back into the formula and calculate: \[ \text{Sensible Heat} = 1.08 \times 2500 \times 12 \]

Perform the multiplication to find the sensible heat: \[ 1.08 \times 2500 = 2700 \] \[ 2700 \times 12 = 32,400 \]

The calculated sensible heat is 32,400 BTU.

Final Answer