Energy Audit of AHU, HVAC

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MGCS-Energy Audit Company
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CASE STUDY AHU ( Air Handling Unit)
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• Technical Specifications of AHU
• Double skinned type AHU with PUF (25 mm thick)
  are provided with EFF1 level motors.
• Blower with paddle blade impeller are provided.
• The belts are V-Belt. Chilled water coil of
  copper tube with finned aluminum fins provided.
• Chiller coils with 6 rows with 12 fins per inch
  spacing provided.
• The fan is so designed with outlet velocity
  restriction upto maximum 10 m/sec. 50mm thick air
  filter with 3 ply HDPE with 2 layers of aluminum
  provided.
• The ducts are of galvanized sheet with suitable
  insulation and support.

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• Location Details
• There are 12 nos of Air handling unit in the
  premises.
• Motors are operated through Star-Delta and DOL
  starter.
• There is no controlling of chilling water or
  other sensor to control AHU.

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Schematic Layout of AHU
Schematic Diagram of AHU
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Performance of AHU
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• TECHNICAL EVALUATION
• From Above Table, 5 out 9 AHU Specific energy
  consumption kW/TR is higher than design.
• RPM of fan also has been derived through formula
  as it connected through V-Belt.
• Through static pressure it can conclude there is
  no obstacles in return air path, G-5 G-6
  considerably on higher side.
• Disadvantage of V-Belt
• There is a power transmission loss of about 5-7,
  when V-Belts WEDGE IN and WEDGE OUT of the
  grooved pulley.
• Advantage of running in Flat Belt
• Prevents elongation due to moisture absorption.
• Ensure Better Grip of Pulley.
• Energy Saving of at least 5-7.

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Energy Saving Recommendation Conversion of
V-Belt to Flat belt in all AHUs between Motor
and Fan. Result of the outcome Energy saving
of at least by 5-7
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Energy Saving Calculations Total Consumption in
AHU 63.05 KW Energy Saving _at_ 7
4.413 kW Energy saving per annum 4.413 X 10
X 240 ( 10 hours ,240 days of working)

10592.4 kWh Monetary Saving
Rs 1.18,105.2/- Investment
50,000/- Payback
5 Months Annual GHG Mitigation 8.78 ton
of CO2
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Energy Conservation-need of the hour
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