Ramesh Kumar Sharma presented on HVAC systems for green buildings. He discussed centralized and localized AC options like chilled water, DX, VRF systems. He covered GRIHA rating criteria and designing efficient HVAC systems using techniques like variable speed pumps and fans, optimized insulation and refrigerants. NTPC is aiming for minimum 3-star GRIHA rating in all upcoming project buildings.

1. PRESENTATION BY:
RAMESH KUMAR SHARMA
MECHANICAL ENGINEER

2. 1. INTRODUCTION
2. A/C SYSTEM – AVAILABLE OPTIONS
3. RATING SYSTEM-GRIHA
4. DESIGN OF HVAC SYSTEM FOR GREEN
BUILDING
5. INITIATIVE BY NTPC
6. A/C SYSTEM ENVISAGED FOR UPCOMING
PROJECTS
7. CONCLUSION

3. 1. Centralized A/C system
 Chilled Water Type
- Water Cooled
- Air Cooled
 D-X Type
- Water Cooled
- Air Cooled
2. Localised A/C system
 Packaged Type Air Conditioners
 Split/Window Type Air Conditioners
 Precision Air Conditioners
2. Variable Refrigerant Flow/Volume

4.  NORMALLY ADOPTED FOR LARGE CAPACITY
DISTRIBUTED LOADS
 SYSTEM REQUIRING CHILLED
WATER,CONDENSER WATER PUMPS,COOLING
TOWERS AND MANY AHUs
 FOR CENTRAL CONTROL ROOMS, CONTROL
EQUIPMENT ROOMS, UPS& BATTERY CHARGER
ROOM,SERVICE BLDGS, ADMN BLDGS,ETC.

5.  USED FOR COMPACT AREAS REQUIRING ONLY
ONE OR TWO AHUs
 AVAILABLE UP TO 100TR
 NO CHILLED WATER PUMP
 SCROLL TYPE NON-
CONDENSING/CONDENSING UNITS ARE USED.

6.  SIMILAR TO D-X TYPE BUT PAC IS A COMPACT
UNIT WITH AHU AS INTEGRAL PART.
 AVAILABLE UP TO 15 TR
 USED IN SMALL CONTROL ROOMS

7.  THESE UNITS ARE D-X TYPE
 ARE AIR COOLED
 USED WHEN LOADS ARE LESS AND ONLY
WINDOW SPACE IS AVAILABLE
 AVAILABLE UP TO 3TR.
 CASSETTE TYPE A/Cs AVAILABLE UPTO 4TR

8.  THESE UNITS ARE DEVELOPED CONSIDERING
FOLLOWING ASPECTS:
 CLOSE TEMPERATURE AND RH CONTROLS.
 24X7 OPERATION
 ENERGY EFFICIENCY- CONSIDERING 24X7
OPERATION.
 HIGH SENSIBLE LOAD AND LESS LATENT HEAT.

9.  TO ACHIEVE ABOVE REQUIREMENTS
FOLLOWING ARE INCORPORATED.
 HIGH ENERGY EFFICIENT SCROLL COMPRESSORS
ARE EMPLOYED.
 LARGER SIZE EVAPORATOR COIL FOR HIGH CFM
TO MEET HIGHER SENSIBLE HEAT.
 DEDICATED HUMIDIFIER AND DEHUMIDIFICATION
FEATURES.
 DESIGNED TO OPERATE EVEN IN WINTER.

10.  SIMILAR TO SPLIT TYPE OF AIR CONDITIONING.
 THE REFRIGERANT FLOW IS VARIED BY USING
INVERTER CONTROLLED VARIABLE SPEED
COMPRESSOR TO RESPOND TO CHANGES IN THE
COOLING OR HEATING REQUIREMENT.
 BY THE COMBINATION WITH THE INVERTER
COMPRESSOR AND THE CONSTANT SPEED
COMPRESSOR, THE COMFORTABLE ROOM
CONDITION WILL BE OBTAINED BY CHANGING THE
COMPRESSOR OPERATION CONDITION.
 VRV CONDITIONS AIR FOR EACH ROOM
INDIVIDUALLY AS PER LOAD REQUIREMENT.

12. Freely Selectable Type of Indoor
Units

13.  VRV SYSTEM CAN WORK BOTH AS
CENTRALIZED AND LOCALISED SYSTEM.
 OPERATING COST OF THE SYSTEM IS
MINIMIZED BY USE OF VARIABLE
REFRIGERANT FLOW CONCEPT.
 MAKE UP WATER IS NOT REQUIRED.
 VRV SYSTEM CAN OPERATE AT PART LOAD.
 TOTAL PIPING LENGTH FROM OUTDOOR
TO INDOOR UNIT CAN BE AS MAXIMUM AS
150M.

14.  LESS SPACE REQUIREMENT AND ALSO EASE IN
INSTALLATION IN EXISTING BUILDING.
 IDEAL FOR CONSTANTLY CHANGING OCCUPANCY.
 DESIGN FLEXIBILITY.
 SILENT IN OPERATION.

15.  CAPITAL COST OF THE SYSTEM IS HIGH.
 LIMITED TO OFFICE BUILDINGS.
 A SEPARATE FRESH AIR SYSTEM IS REQUIRED.
 NO CONTROL OVER HUMIDITY.
 SKILLED MANPOWER REQUIRED FOR
MAINTENANCE AT SITE.

16. ———————————————————————————————————————————
Sl.No. Area to be air-conditioned Type of air conditioning
equipment/system
—————————————————————————————————————————
1. Control Tower areas Vapour absorption machine and screw
(including Control room, /centi type chiller unit with chilled water
system
Control Equipment room,
UPS room and SWAS) .
-Control room for Electro
static Precipitator
-Service Building
2. Administrative Building Screw/Centrifugal type chiller units with
chilled water system
3. Township Auditorium Screw type chiller units with chilled water
system
———————————————————————————————————————————

17. Sl.No. Area to be air-conditioned Type of air conditioning equipment
——————————————————————————————————————
4. Offsite Control rooms of PAC/Ductable & Non ductable
various pump houses Split Air Conditioner
5. Switchyard Control room Water Cooled/Air Cooled Scroll/
Building Reciprocating type units
6. Water System Control Bldg Air Cooled scroll/reciprocating
type
7. Office building in metros VRV system
8 . Server room (independent) Precision AC

18.  REDUCTION IN DEPLETION OF NATURAL
RESOURCES.
 GRIHA (GREEN RATING FOR INTEGRATED
HABITAT ASSESSMENT). NATIONAL RATING
SYSTEM OF INDIA.

19. Points scoredPoints scored RatingRating
50-6050-60
61-7061-70
71-8071-80
81-9081-90
91-10091-100

21.  Selection of Chillers
 Selection of Pumps
 Selection of Cooling Tower
 Selection of AHU’s
 Selection of Insulation
 Selection of Refrigerant
 Indoor Air Quality
 Noise & Vibration Control

22.  USE SCREW/CENTRIFUGAL/SCROLL
COMPRESSORS.
 CHILLER SHOULD BE AHRI CERTIFIED.
 MIN. COP OF CHILLER( WATER COOLED)
SHOULD BE 5.4 (FOR 150-300 TR) AND 3.05
FOR AIR COOLED CHILLERS ABOVE 150 TR.
 AVOID OVER DESIGNING OF CHILLERS.

23.  PRIMARY AND SECONDARYPRIMARY AND SECONDARY
ZONAL CHILLED WATERZONAL CHILLED WATER
PUMPING SYSTEM MUST BEPUMPING SYSTEM MUST BE
ENVISAGED.ENVISAGED.
 EACH SECONDARY PUMPEACH SECONDARY PUMP
PROVIDED WITH VFD; VARIESPROVIDED WITH VFD; VARIES
CHILLED WATER FLOWCHILLED WATER FLOW
THROUGHTHROUGH
THE COOLING COIL OF AHU’S ASTHE COOLING COIL OF AHU’S AS
PER DEMAND WHICH RESULTS INPER DEMAND WHICH RESULTS IN
ENERGY SAVING.ENERGY SAVING.
 CONDENSER WATER PUMPCONDENSER WATER PUMP
PROVIDED WITH VFD TO VARYPROVIDED WITH VFD TO VARY
WATER FLOW ACCORDING TOWATER FLOW ACCORDING TO
CHILLER REQUIREMENTCHILLER REQUIREMENT

24.  INDUCED DRAFT, CROSS
OR COUNTER FLOW.
 BIRD SCREEN ON TOP OF
TOWER.
 COOLING TOWER FAN
PROVIDED WITH VFD.

25.  VARIABLE VOLUME TYPEVARIABLE VOLUME TYPE
WITH DOUBLE SKINWITH DOUBLE SKIN
CONSTRUCTION.CONSTRUCTION.
 USE CENTRIFUGAL FANUSE CENTRIFUGAL FAN
WITH VFD WHICH RESULTSWITH VFD WHICH RESULTS
IN ENERGY SAVING.IN ENERGY SAVING.

26.  CONFORM TO IS STANDARDS
 BE ODP FREE (CRITERIA NO.-27)
 HAVE HIGH NOISE REDUCTION COEFF.
(NRC) (CRITERIA NO.-29)
 MAX. R VALUE OF INSULATION 2.1 M2
-K/W
AND U-VALUE 0.409 W/M2
-K AS PER ECBC
CODE
 BE RECYCLABLE
 INSULATION SHOULD BE CFC/HCFC FREE
Resin bonded glass wool / Resin bonded
mineral wool / Expanded Polystyrene

27.  ODP FREE (CRITERIA NO.27)ODP FREE (CRITERIA NO.27)
 HAVING MINIMUM GWPHAVING MINIMUM GWP..
 CFC/HCFC FREE.CFC/HCFC FREE.
 CHOOSE EITHER HFC’S ORCHOOSE EITHER HFC’S OR
AZEOTROPIC REFRIGERANTS.AZEOTROPIC REFRIGERANTS.
Currently we are demanding for anyone out of these refrigerants:Currently we are demanding for anyone out of these refrigerants:
R-134a / R-410AR-134a / R-410A

29.  SCREW/CENTRIFUGAL CHILLER FOR MAIN
PLANT A/C SYSTEM. NO VAM
 PRIMARY AND SECONDARY CHILLED WATER
PUMPS.
 VFD IN SECONDARY CHILLED WATER PUMP.
 AHUS WITH VFD DRIVEN FAN.
 CONDENSER WATER PUMP FITTED WITH VFD.
 COOLING TOWER FAN VFD DRIVEN.
 USE OF R-134A INSTEAD OF R-22 AS R-134A
HAS A TEWI 13% LESS THAN R-22.

30. ———————————————————————————————————————————
Sl.No. Area to be air-conditioned Type of air conditioning
equipment/system
---------------------------------------------------------------------------------
1. Control Tower areas Screw/Centrifugal type chiller unit with
chilled water system & AHUs with VFD
Control Equipment room,
UPS room and SWAS)
Control room for Electro
static Precipitator
2. Service Building Screw/centrifugal type chiller unit with
primary & secondary chilled water system
& VFDs
3. Administrative Building Screw/Centrifugal type chiller units with
primary & secondary chilled water system
& VFDs
4. Township Auditorium Screw/scroll type chiller units with chilled
water system & AHUs with VFD
—

31. Sl.No. Area to be air-conditioned Type of air conditioning equipment
——————————————————————————————————————
5. Offsite Control rooms of Cassette/ Non ductable
various pump houses Split Air Conditioner
6. Switchyard Control room Water Cooled/Air Cooled Scroll
Building type units with VFD driven AHUs
7. Water System Control Bldg Air Cooled scroll type with VFD
driven AHUs
8. Office building in metros VRV system
9. Server room (independent) Precision AC

32. NTPC has initiated the process of
designing green building and has
decided to construct all its non-plant
buildings and township buildings for all
upcoming projects with minimum
GRIHA 3-star rating.

33. Name of BuildingName of Building RatingRating
Administrative Building,Administrative Building,
Service BuildingService Building
4-Star4-Star
CanteenCanteen 3-Star3-Star

34. Name of BuildingName of Building RatingRating
Hospital, Bal Bhawan & LadiesHospital, Bal Bhawan & Ladies
Club, Training Center, etc.Club, Training Center, etc.
4-Star4-Star
GM Bungalow, Guest House,GM Bungalow, Guest House,
Quarters (all type), Auditorium,Quarters (all type), Auditorium,
Community Center, SwimmingCommunity Center, Swimming
Pool, etc.Pool, etc.
3-Star3-Star