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Sample 1 |
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| Design Step 3: |
| Now we must find air temperature & humidty of supply
air before AHU (air handling unit ) heat exchanger |
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| Supply air absolute humidity:8.2 g/kg |
| Outside air absolute humidty: 1.2 g/kg |
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| Because of humidity difference we must supply water to air
for increasing humidity |
| W=m*(w2-w1) |
| W=Water quantity in kg |
| m=Air Mass Quantity in kg |
| m=V*q |
| V=Air SupplyAmount in m3/h |
| q=Air Density in kg/m3 :1,2 kg/m3 |
| m=10,000*1,2=12,000 kg |
| w2:Room air absolute humidity:8,2 g/kg |
| w1=Outside air absolute humidity:1,2 g/kg |
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| W=12000 (8.2-1.2)=84000 gr/hr=84 kg/hr |
| We must supply 84 kg/hr of water to supply air |
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| After humidifier air will enter to heat exchanger.We can't
control exit humidity of air after humidifier. |
| We accept exit humidity after humidifier as %90 <5> |
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| Air in wet type humidifier (air washer ) will follow wet
bulb line.(Wet bulb will be constant ) |
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| From chart we see that we need and heat exchanger before
humidifier . |
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| Design Step 4: |
Required Heating Capacities. |
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| .4.a-Heating Coil Capacity (from outside air to humidifier) |
| Formula: Q=m*C*DT |
| Q1=10,000*1,2*0,24*(30-(-12))=120,960 kcal/h |
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| .4.b-Reheater ,Heating Coil Capacity (from exit of humidifier
to supply) |
| Formula: Q=m*C*DT |
| Q2=10,000*1,2*0,24*(39,3-13))=75,744 kcal/h |
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| Total required heat capacity of air handling unit |
| Q=Q1+Q2=120,960+75,744=196,704 kcal/h |
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