HVAC system

SUBMITTED BY-

● Aditya Sharma ➔ 201110202

● Sachin Verma ➔ 201110201
● Ronak Agrawal ➔ 191110216
● Diwakar Karn ➔ 201110203
● Poorva Lele ➔ 201110246
● K. Gurunath ➔ 201110247
HVAC-
HEATING: Heating is provided by heaters. This can be done via central heating or by
direct heating system.

VENTILATION: Ventilating or ventilation (the V in HVAC) is the process of exchanging

or replacing air in any space to provide high indoor air quality which involves
temperature control, oxygen replenishment, and removal of moisture, odours, smoke,
heat, dust, airborne bacteria, carbon dioxide, and other gases.

Methods for ventilating a building may be divided into -1. mechanical /forced 2. natural
types

Air-Conditioning: An air conditioning system provides cooling and humidity control for
all or part of a building.
Functions of HVAC

● To Control Temperature.
● To Control Humidity.
● To Develop Differential Pressure.
● To Prevent Cross Contamination.
● To Maintain proper Air Movement
Air Conditioning-
There are two types of Air-Conditioning system.
DUCTED

1. Ducted

2. Non Ducted CHILLED SYSTEM DIRECT EXPANSION SYSTEM

NON- DUCTED

WINDOW SYSTEM SPLIT SYSTEM

CHILLED SYSTEM-
Chilled system- In a chilled water system the refrigeration
system is in a chiller which is used to first chill the water,
which is then used to chill the air used for cooling the rooms
or spaces.

Chilled air system/ Air cooled chiller-Chillers-

Recommended when water is either in scarce supply
and/or expensive or in case the ambient conditions are
favourable.

Water cooled chiller-Water-cooled chillers are more energy

efficient than the air cooled chillers but do require a cooling
tower which demands a supply of suitably treated water.
 Non Ducted System
Window system- Window system is the most
commonly used air conditioner for single rooms.
In this air conditioner all the components, namely
the compressor, condenser, expansion valve or
coil, evaporator and cooling coil are enclosed in a
single box. This unit is fitted in a slot made in the
wall of the room, or more commonly a window.

Req- 1-2 Ton Ac

 Non Ducted System
Split System- The split air conditioner comprises of two parts,
i. Outdoor unit ii. Indoor unit The outdoor unit, fitted outside
the room contain components like the compressor, condenser
and expansion valve. The indoor unit comprises the
evaporator or cooling coil and the cooling fan.

Used in places where room is not available.

 AHU- Air Handling Unit- Centralised System
● An air handler is usually a large metal box
containing a blower, heating or cooling elements,
filter racks or chambers, sound attenuators, and
dampers.
● An air handling unit is a device used to regulate and
circulate air as part of the heating, ventilation and air
conditioning system.
● The AHU takes in outside air, reconditions (filtered
and either heated or cooled) it and supplies it as
fresh air to the air conditioned room.
 Considerations for Refrigerants-

● Refrigerant with zero ODP and low GWP

should be adopted for balance approach
considering overall environmental impact.
● Flammability-The refrigerant should
preferably be non-flammable/ having
flammability as low as possible.
● Toxicity-The refrigerant should have toxicity
as low as possible.
● The refrigerant should also support other
key performance parameters, including high
energy efficiency, low emissions, high COP,
chemical and thermal stability and material
compatibility.
Sizing Commercial HVAC
HVAC sizes are measured in tons.

Most commercial HVAC systems range between 2 tons and 30 tons. A 1 ton HVAC can
remove around 12,000 Btu (British Thermal Units) of heat per hour. It is needed to
calculate the building’s cooling load to know the appropriate capacity of the air conditioner
to use.

Building’s cooling load depends on several factors such as average external temperature
to building design, orientation, and its primary purpose. However, a general rule of thumb
is that it takes approximately 25 Btu to cool one square foot.
How To Determine The Size Of The HVAC
Unit In A Commercial Building
A rough estimation of the cooling capacity that a commercial HVAC system would need
based on data by EnergyStar.gov.

Preferred to use 1 ton per 200 sq foot of floor area as a general rule of thumb.
Ducting-
DUCT SHAPES

i. Rectangular Duct

ii. Circular Duct

iii. Square Duct

iv. Spiral Duct

Ducting-
MATERIAL-All ducts shall be fabricated either from Galvanised Sheet Steel or aluminium
sheets

The thickness of sheets for fabrication of rectangular ductwork shall be as under. The
thickness required corresponding to the longest side of the rectangular section shall be
applicable for all the four sides of the ductwork.
Ducting- Construction

● Ducts shall be fabricated at site or factory fabricated and shall be generally as per IS: 655
"Specifications for metal air ducts".
● All the ducts upto 600 mm longest side shall be cross broken between flanges by a single
continuous breaking. Ducts of size 600 mm and above shall be cross broken by single
continuous breaking between flanges and bracings. Alternatively, beading at 300 mm centres
for ducts upto 600 mm longest side, and 300 mm centres for ducts above 600 mm size shall
be provided for stiffening.
● The ratio of the size of the duct to the radius of the elbow shall be normally not less than
1:1.5.
● Flanged joints shall be used at intervals not exceeding 2500 mm.
● Stiffening angles shall be fixed to the sides of the ducts by riveting at 1.25 meters from joints
for ducts of size 600 mm to 1500 mm, and 0.6 mm from joints for ducts of size larger than
1500 mm.
● Stiffening angles shall be fixed to the sides of the ducts by riveting at 1.25 meters from joints
for ducts of size 600 mm to 1500 mm, and 0.6 mm from joints for ducts of size larger than
1500 mm.
● All factory fabricated duct shall be supplied in L sections, the length of any piece shall not be
more than 1800 mm for duct with longest side of cross section as 600 mm and above and
3000 mm for rest.
Ducting-Air outlet and inlet
● Square and rectangular wall outlets shall have a flanged frame with the outside edges
returned or curved 5 to 7 mm and fitted with a suitable flexible gasket between the
concealed face of the flanges and the finished wall face.
● Louvers may be spaced 18 mm apart.A bird wire screen made of 12 mm mesh in 1.6
mm steel wire held in angle or channel frame shall be fixed to the rear face of the louver
frame by screens.
● Square and rectangular ceiling outlets/intakes shall have a flange flush with the ceiling
into which it is fitted or shall be of anti smudge type.
● Circular ceiling outlets/intakes shall have either flush or anti smudge outer cone as
specified in the tender specifications. Flush outer cones shall have the lower edge of the
cone not more than 5 mm below the underside of the finished ceiling into which it is
fitted. Anti smudge cones shall have the outer cone profile designed to reduce dirt
deposit 104 on the ceiling adjacent to the air outlet.
● Laminar supply air diffusers shall be made of 2mm thick powder coated aluminium
sheet duly insulated with 5mm thick closed cell polyethylene foam insulation having
factory laminated aluminium foil and joints covered with self adhesive aluminium tape
and having holes 2/3 mm dia including frame work.
Ducting- Fire dampers

Fire dampers shall be provided in all the supply air ducts and return air ducts (where
provided), return air passage in the air-handling unit room and at all floor crossings.

Fire dampers shall be multi blade louvers type.

Fire dampers shall be compatible with the fire detection system of building & shall be
capable of operating automatically through an electric motor on receiving signal from fire
alarm panel.
 REQUIREMENTS
WINDOW TYPE A.C. -
Window A.C. are available in standard rating of 1, 1.5, 2 TR these are
provided where-
(i) Window for fixing the AC is available or necessary opening in wall
is provided for the purpose.
(ii) Sound level of up to 50 dB inside the room is acceptable.
(iii) These types of A.C.s are efficient & easy to maintain as compared
to split A.C.

SPLIT TYPE A.C -

(i) Where window for installation of WTAC is not available, Split Type
AC are planned.
(ii) Almost Silent (Low dB level) operation of A.C is important,
considering VIP rooms, conference rooms, etc.
REQUIREMENTS

VRV/ VRF SYSTEM: These systems are

basically extensions of split type A.C‘s and
are much less efficient as compared to central
A.C. plant hence should not be provided
except in following cases-

i. In the existing building, requiring central

AC but the space for providing AC plant,
height of ceiling for ducting, water supply for
chilled water based AC plant, is not available.

ii.It is not possible to provide central A.C.

plant and run the chilled water lines up to cool
the rooms with fan coil units to cool the
rooms.
REQUIREMENTS
PACKAGED TYPE UNITS
These are best suited for air conditioning of areas up to
about 450 sqm (about 30 TR A/C load) located adjacent
to each other. Beyond this central plant is generally more
economical. These are generally available in 5 TR, 7.5
TR, 10 TR , 15 TR and 20 TR capacities.

CENTRAL PLANTS- For capacities larger than 100

TR, it is generally economical to go in for central plants.
Reciprocating type central air conditioning plant.
These plant use reciprocating compressor. These are
available in capacities ranging from 30 TR to 110 TR.
Screw type central air conditioning plant. These
plants use screw type compressors. These are generally
used in capacities ranging from 80 TR and up to 400 TR
at present.
 REQUIREMENTS

AC TONNAGE CALCULATION OF A ROOM OF

14FT BY 15FT
AREA REQUIREMENTS
AREA REQUIREMENTS
CMM FORMULA

PACKAGED TYPE PLANT

Space Requirements i)The floor area

requirement for installation of the
packaged type plant room shall be as
under: a)Single Unit: 3 m X 2.5 m
b)Double Units: 3 m X 4 m c)Triple
Units: 3 m X 5 m
AREA REQUIREMENTS
 AREA REQUIREMENTS
WEATHER MAKER / AHU ROOMS PACKAGED TYPE PLANT

Space requirements i)Floor area requirement Space Requirements i)The floor area requirement for
for the AHU room shall be as under: For AHUs installation of the packaged type plant room shall be
upto 340 CMM : 4.5 m X 3.5 m For AHUs as under: a)Single Unit: 3 m X 2.5 m b)Double Units:
between 340 CMM & 680 CMM : 5.5 m X 4.5 m 3 m X 4 m c)Triple Units: 3 m X 5 m

COOLING TOWERS
 Best AC Brand In India - The Hindu
Recommended Air Conditioner Online Shopping site in India
https://www.quora.com/
Brands in India
1. LG 1.5 Ton 5 Star AI DUAL Inverter Split AC

Dimensions: 23.5 x 97 x 30 Cms

Prices: Rs 45000

Reasons to buy:

● Most energy-efficient product in this price range saves money on electricity bills.
● It works well even if there are multiple people present in the room because of its 110% capacity mode.

With 4.3/ 5.0 stars, this product has managed to satisfy a huge number of its buyers with its
durability and multi-mode compatibility.
2. Blue Star- Blue Star 1.5 Tr 3 Star Inverter Split AC

Dimensions: 85.8 x 32.7 x 53.6 Cms

Prices: Rs 35990

Reasons to buy:

● Saves money on electricity bills with its eco settings

● Cools well in every weather condition
● Durable body that is protected from corrosion and leakage

Users rated this AC 4.5 out of 5.0 for operating at low noise and low-power consumption
levels.
3. CROMA 1 Ton 3 Star Smart Convertible Inverter Split AC

Dimensions: 80 W X 23 D X 29.5 H in cms

Prices: Rs 33490

Reasons to buy:

● Seamless working in every weather condition

● Multiple features elongate the life of the body
● Best fast cooling in hot and humid temperatures up to 54°
● Most affordable option in this array of features

Users are happy with the practical and fast cooling in the months of summer and have given
the product a decent rating of 4.0 out of 5.0.
 CASE STUDY- People’s Hospital
● The capacity of 50 bed Hospital
● NO VENTILATION IN GENERAL WARDS
AND CORRIDORS
● SPLIT AC IN ICU,PICU, HOD CABIN,
DIRECTOR {2 TN}
● CENTRALISED AC ONLY IN ICCU ,MICU
AREA ABOUT 1500-2000 SQM
● AUDITORIUM ALSO WITH DOUBLE DUCT
● PLANT PLACES ON TERRACE APPROX 5
BY 10 FT
● 4 UNITS OF 20 TON AC