If an exhaust fan operates continuously at 70 CFM with an annual HDD of 5345, what is the energy transfer in BTUs for the year?

To calculate the energy transfer in BTUs for the year from a continuously operating exhaust fan, we need to consider the airflow rate in cubic feet per minute (CFM) and the annual heating degree days (HDD). The given annual HDD of 5345 is a measure of the demand for heating in a specific location.

First, we can determine the total airflow in a year. If the exhaust fan operates at 70 CFM, we can convert this to a yearly volume of air moved:

1. Calculate the total minutes in a year:

• There are 60 minutes in an hour and 24 hours in a day, so:

• 60 minutes/hour × 24 hours/day × 365 days/year = 525,600 minutes/year.

2. Calculate the total volume of air moved by the fan in a year:

• 70 CFM × 525,600 minutes = 36,192,000 cubic feet of air per year.

Next, we need to relate the amount of air being exhausted to energy transfer in BTUs. The calculation for the energy transfer involves the formula:

Energy (BTUs) = CFM × 1.08 × (Temperature change) × Hours of operation.

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