The size of the safety factor is dependent on the accuracy of the wattage calculation.
Cartridge heater watt calculation.
Kw your kilowatt requirement.
Suppose you wanted to calculate the radiation loss.
Then use graph g 235 to be sure that the watt density is within allowable limits.
L radiation radiation loss w in 2 x area x emissivity x 1 hr for example assume the tin block has a radiation loss of 1 1 w in 2 and an emissivity of 0 04.
A factor of 10 is adequate for small systems that are closely calculated.
Heat calculations watt density for cartridge heaters other heater applications.
So the formula for calculating heat loss due to radiation is.
Watt density w p x d x hl.
Thus for a 1 2 x 12 heater rated 1 000 watts the watt density calculation would be as follows.
It is the number of watts per square inch of heated surface area.
Heaters should always be sized for a higher value than the calculated figure.
How to calculate required wattage.
Kw w x c x t w weight of material in lbs.
Are you looking to calculate surface heater wattage.
Standard air is 70 degf 14 psi scfm stands for standard cubic feet per minute and delta t exit temperature minus inlet temperature in degrees fahrenheit.
Calculate watt density and fit after the wattage for each heater has been established the watt density and fit must be calculated.
Kw scfm x delta t 3000 x 1 2 this formula can be used for standard air.
In order to determine whether a particular heater will perform well in your application you must compare its wattage with your requirements.
Thus for a 1 2 x 12 heater rated 1000 watts the watt density calculation would be as follows.
For calculation purposes cir stock cartridge heaters have 1 4 unheated length at each end.
Manual calculation of total heat requirements for insertion heaters applications.
For calcualation purposes stock cartridge heaters have a 1 4 unheated length at each end.
For example a 1 2 x 12 cir heater rated 1000 watts has a watt density of 55 w in2.
Watt density w π x d x hl.
Kw wt x cp x δ t 3412 x h where.
20 additional wattage is more common.
The first thing to know is how many pounds of air need to be heated.
