re FAN EFFICIENCY FORMULA DERIVATION

Thanks Ahmed, for the nicely worked example.

Regards,

Ted.

Reply

Know the answer to this question? Join the community and register for a free guest account to post a reply.

re FAN EFFICIENCY FORMULA DERIVATION

Hello Sidhant,

There are two mistakes. The first mistake is in this line;-

WATT = M3/S x MMWC/9.8

Here's why;-

1Pa = 1/9.8  mmWC  =  0.102  mmWC

Therefore to convert a pressure value in mmWC to Pascals you need to DIVIDE by 0.102,  NOT divide by 9.81, as you have done.

Here's an example;- If 1Pa = 0.102mmWC then 1000Pa=102mmWC. So to convert the 102mmWC back into Pascals you have to divide by 0.102, which gives us 102/0.102 = 1000Pa.

So the line should be;-

WATT = M3/S x MMWC / 0.102

The second mistake is in this line;-

1000xWATT = 1000 x M3/S x MMWC/9.8

You must DIVIDE  a value expressed in Watts by 1000 to get kW, not multiply.

ie. 1000 Watts = 1kW  Therefore (Watts / 1000) = kW

So the line should read;-

kW = (M3/S x MMWC / 0.102) /1000

or;-

kW =(M3/S x MMWC) / 102

I hope that makes it clear.

I think the root of the problem is that you are getting mixed up between values and measurement units. It's best to use variables when performing operations on algebraic equations. Using measurement units as variables can lead to confusion.

Regards,

Ted

Reply

re FAN EFFICIENCY FORMULA DERIVATION

Dear Sidhant,

I hope with the examples given by Ted and Ahmed your doubt is clear. I have also given you an example for the same. The mistakes are nicely explained by Ted and Ahmed .Rectifiy the same and you will find the process calculations are going very smooth for you.

regards

vdchari

Reply