A 110-volt electrical heater is used to warm of air at 95 kPa and 15°C to 95 kPa and 30°C. How much current, in amperes, must be supplied to this heater? Amperes (Round to one decimal place)
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I stuck with this problem and the solution on our web forthisproblem post by --Craig-- seem to be the wrong (not evendoanything with the problem, I think he put wrong one). PLeasehelpme out.An electric heater is used to heat a room of volume61m3. Air is brought into the room at 2 degree C andiscompletely replaced twice per hour. Heat loss through thewallsamounts to approximately 900 kcal/h. If the air is to bemaintainedat 25 degree C, what minimum wattage must the heater have?(Specific heat of air is about .17 kcalC/kg)THanks.
(a) The inside of a hollow cylinder is maintained at a temperature , and the outside is at a lower temperature, (Fig. 19.45). The wall of the cylinder has a thermal conductivity k. Ignoring end effects, show that the rate of energy conduction from the inner surface to the outer surface in the radial direction is
Suggestions: The temperature gradient is . A radial energy current passes through a concentric cylinder of area .
(b) The passenger section of a jet airliner is in the shape of a cylindrical tube with a length of and an inner radius of . Its walls are lined with an insulating material in thickness and having a thermal conductivity of . A heater must maintain the interior temperature at while the outside temperature is . What power must be supplied to the heater?
