Question

A GRAIN DRIER REQUIRES 12000 CU ft PER MIN OF 115 F AIR .THE ATMOSHPHERIC AIR IS AT 75F AND 68 PER CENT RELATIVE HUMIDITY. HOW MANY BRITISH THERMAL UNITS PER HOUR ARE REQUIRED TO HEAT THE AIR?

Answer 1

To calculate the number of British thermal units (BTUs) per hour required to heat the air, you will need to use the following formula:

BTUs per hour = flow rate (in cubic feet per minute) * temperature change (in degrees Fahrenheit) * specific heat of air * density of air

Plugging in the values provided in the question, we get:

BTUs per hour = 12000 cu ft/min * (115 F - 75 F) * 0.24 BTU/lb/F * (1/0.075 lb/cu ft)

Solving for BTUs per hour, we get:

BTUs per hour = 12000 cu ft/min * 40 F * 0.24 BTU/lb/F * (1/0.075 lb/cu ft)

= 12000 cu ft/min * 40 F * 0.24 BTU/lb/F * (1/0.075 lb/cu ft)

= 489600 BTUs per hour

Therefore, the grain drier requires 489600 BTUs per hour to heat the air from 75 F to 115 F.

Step-by-step explanation: