HP HP-11C User Manual

Your HP-11C: A Problem Solver 11
To see the close relationship between manual and programmed
problem solving, let’s first calculate the solution to a problem
manually, that is, from the keyboard. Then we’ll use a program to
calculate the solution to the same problem and others like it.
Most conventional home water heaters are cylindrical in shape.
You can easily calculate the heat loss from such a tank using the
formulaq =h X A X T, where:
q is the heat loss from the water heater (Btu per hour).
h is the heat-transfer coefficient.
A is the total surface area of the cylinder.
T is the temperature difference between the cylinder and the
surrounding air.
Example: Assume you have a 52-
gallon cylindrical water heater and
you wish to determine how much
energy is being lost because of poor
insulation. In initial measurements,
you found an average temperature
difference between the heater surface
and surrounding air of 15 degrees
Fahrenheit. The surface area of the
tank is 30 square feet and the heat
transfer coefficient is approximately
0.47. To calculate the heat loss of the
water heater, simply press the follow-
ing keys in order.
Keystrokes Display
15 15.0000 Input temperature
30 30 difference (T) and area of
water heater (A).
450.0000 Calculates A X T.
47 0.47 Heat-transfer coefficient
(h).
211.5000 Heat loss in Btu per hour
(h X(AT)).
(«] 0.0000 Clears display.

HP HP-11C Specifications

General

Brand	HP
Model	HP-11C
Category	Calculator
Language	English