I am calculating supply air flow rate into a zone because that an air air conditioning system. The simulation software offers the an outcome in m3/s but the mathematics formula the I offered takes in kg/s.

You are watching: Kg/s to m^3/s

Do I need to convert the flow rate, and if so, how do i convert in between kg/s and also m3/s?

You require to think about the thickness of the air, i beg your pardon varies v temperature and also air pressure. At 15 levels Celsius, at sea level, the thickness of waiting is 1.225 $kg/m^3$. The table here offers air densities in ~ 5 degree intervals.

Now density is mass separated by volume,

$\rho = m/v$

Hence, to obtain the volume circulation rate (in $m^3/s$), for a understand mass flow rate, division the mass circulation rate (in $kg/s$) by the thickness (in $kg/m^3$).

Thus, a flow rate that $1 kg/s$ is,

$1 / 1.225 = 0.8163 m^3/s$

To obtain the mass circulation rate for a understand volume flow rate lot of the volume circulation rate by the wait density.

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edited Apr 21 "15 at 13:48

Trevor Archibald
answer Apr 21 "15 at 4:59

FredFred
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HVAC-Systems usually offer a Volume-Flow-Rate, thus $m^3/s$. If you need Mass-Flow-Rate ($kg/s$) you merely need come multiply v the density ($\rho$) of the fluid. The thickness can be calculated utilizing the ideal gas law (see 1):

$$\rho_s = \fracp_sR T_s$$

Please observe the you require static worths for the push ($p_s$, check out 2) and also temperature ($T_s$, check out 3). The specific gas constant ($R$, watch 4) because that air is depending upon the humidity the the air however $287.058 J/kg/K$ is a an excellent starting point. For short velocities static and absolute values space so close come each other that you should have the ability to use the absolute/ambient pressure and also Temperature. However, the density is an altering with pressure and also temperature, neglecting either will certainly decrease the accuracy the the measurement.

From my endure the HVAC system has actually a measurement-error ($5\%$) i m sorry is bigger than the error which is made by suspect static=total.

All values in SI units!

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edited Apr 21 "15 in ~ 5:30
answer Apr 21 "15 at 5:09

rul30rul30
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## Constant massive Flow:

$$\dotm = \rho A V$$

(Hence mass flow is same to density times area time velocity.

So presume you have an area that $1$ m^2 through a velocity of $1$ m/s, air with a density of $1.225$ kg/m^3 will certainly equate to a mass circulation of $1.225$ kg/s. Because that incompressible flows, the mass flow rate is constant.

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reply Apr 21 "15 at 16:42
BeyondLegoBeyondLego
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You need to understand that whilst the circulation rates might remain static, the mass will certainly not be so due to the fact that warmer wait is lighter and also less dense whilst chill aircon air is considerably heavier. The difference between them identify the power compelled to transport the wait by the machine to the zone her looking into.

The distinction in calculations is come answer two various questions: power usage or airflow m^3 \cdot s

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reply Jul 11 "18 at 2:09
RhodieRhodie
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