The calculation of heat and air volume

                                                   The calculation of heat and air volume

How to calculate the air volume of products needed for fan

- should be different customers in different areas, manufacturers have a duty to guide customers how to choose the appropriate air volume, we will choose method, air volume is introduced as follows:

You must know some known conditions:

1.1 card is equal to 1 g weight 0? Water makes the temperature rise of 1? The heat required.

2.1 watts of power to work 1 second is equal to 1 bajaur.

Card is equal to 3.1 4.2 bajaur

4. The constant pressure of air (10 mmaq) specific heat (Cp) = 0.24 (Kcal/Kg?

5. Standard state: air temperature 20? , atmospheric pressure, 760 MMHG, moist air humidity of 65% for the standard air, this time the weight of per unit volume of air (than) weight of 1200 g/M * 3

6. The CMM, CFM is refers to the exhaust air volume per minute, the former unit for the m3 / minute; The latter unit for cubic feet per minute. 1 the CMM = 35.3 CFM.

2, the formula calculation

A, that fan total discharge quantity of heat (H) = specific heat (Cp) by weight (W) x containers allow temperature rise (? Tc)

Because: the weight W = (CMM / 60) between x D = unit volume times the density (per second)

= (CMM / 60)? 1200 g/M * 3

= (Q / 60) x 1200 g/M * 3

So, total quantity of heat (H) = 0.24 (Q / 60)? 1200 g/M * 3?? Tc

2, electric heat (H) = (P [s] [power] t) / 4.2

Three, informed by 1, 2:0.24 (Q / 60)? 1200 g/M * 3?? Tc = (P? T) / 4.2

Q = (P * 60) / 1200? 4.2? 0.24?? Tc

Q = 0.05 P /? Tc.......................................................................................... (CMM)

= 0.05? 35.3 P /? Tc = 1.76 P /? Tc................................................ (CFM)

Four, conversion degree Fahrenheit as: Q = 0.05? 1.8 P /? Tf = 0.09 P /? Tf............................................. (CMM)

= 1.76? 1.8 P /? Tf = 3.16 P /? Tf................................................ (CFM)

? TOP

3, sample

Example 1: there is a computer 150 watts of power consumption, consumption of fan 5 watts, when summer temperatures the kagyu 30? 60, set the CPU to allow work? , the fan air volume calculation is as follows:

P = 150 w + 5 w = 155 w. ? Tc = 60-30 = 30

Q = 0.05 x 155/30 = 0.258 CMM = 9.12 CFM (air volume required for work)

So, should choose the actual air volume for the fan of Qa

Example 2: a SWITCHING power supply 250 watts of power consumption, consumption of fan 20 watts, local