7/25/2019 To calculate the A.pdf

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To calculate the A/C cooling load at split unit / AHU / ACPU / WCPUand compare with actual capacity:

Testing equipment:

1- Air Flow meter

2- Thermometer3- Measuring tape.4- Psychrometric chart or schedule

Data required:

1- Measure return air velocity (air flow rate) using the unit Liter/second2- Measure return and supply dry air temperature and relative humidity3- Measuring the area of return air flow (area of air filter) using the unit : Foot

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Calculation

To Calculate sensible heat in KWr use the formula below:

KWs= 1.21 * l/s * (T) C / 1000 = KWr

To calculate Latent heat in KW should use Psychrometric chart to get moisture content for each temperature

KWl = 3 * l/s * ( m) g/kg /1000 = KWr

Total A/C heat load = KWs+ KWl = KWr

Convert to BTU = KWr * 3,412

Where:

T in Celsius (return air temperature - supply air temperature)

m in g/kg Humidity ratio (Moisture content at return air Moisture content at supply air)

Measure Air speed in foot /Minute

Air flow = air speed * Area = CFM the convert to Liter/Second

Remarks:

- May you down load Psychrometric chart calculator at you PC from web address as below:

http://www.sugartech.co.za/psychro/

Enter your Temperature and Relative humidity can get Moisture content in kg/kg

Then multiply by 1000 to get Humidity ratio (moisture content) in (g/ kg).

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