Hvac

HVAC

2.0 HVAC

2.2 Refrigeration Cycle

1. Freon* is a gas at normal temperature

and pressure. It is first subjected to high

pressure in a compressor which raises its

boiling point and temperature.

2. At the same high pressure, the vapor is

piped into condenser coils where it is

cooled by water to a degree below its

liquefaction point. It condenses into a

liquid state and still under high pressure,

passes to the evaporator.

3. In the evaporator, the pressure is

relieved by the suction stroke of the

compressor. The boiling point of the

liquid refrigerant drops and evaporation

into a vapor takes place. The water

which surrounds the evaporator coils

gives up its heat in causing the

vaporization at low pressure, thus

reducing its temperature to the

temperature of the refrigerant. The cold

water can then be piped at this low

temperature to any desired point and

sprayed to cool the passing air. The

refrigerant is sucked back into the

compressor and the cycle recommences

*Freon - refrigerant used for cooling.

Mechanical refrigeration is based upon the

alternate liquefying and evaporating of a volatile

liquid with a low boiling point usually Freon 12

(Dichlorodiflouromethane) or Freon 11

(Trichloromonoflouromethane) during which

processes it respectively gives off and takes in

heat. The desirable properties of Freon are: a)

high heat of vaporization; b) moderate pressure

change for low to high temperature range; c)

non-toxic; d) incombustible; e) non-explosive;

and f) non-corrosive.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.3 Types of Air-

Conditioning Systems

1. Central Systems

All-Season Centralized Air

Conditioning System consists of

the following:

a. A method of cooling,

a refrigeration plant

b. A source of heating

such as a boiler or

furnace

c. An Air Handling Unit

(AHU) equipped with

filters, pre-heater,

spray, cooling coils

and re-heater

d. The air distributing

equipment composed

of ducts, fans and air

outlets

e. The necessary

manual or automatic

controls

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

3. Passing the air through coils

containing the refrigerant itself; in

this case the coils are called “direct

expansion” coils

4. Passing the air through a

combination of sprays and coils

2.1.4 Methods of Cooling

and De-humidifying

1. Passing the air through a spray of

cold water

2. Passing the air through coils

containing cold water

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.1.3 Air-Conditioning

Standards

1.Cooling and De-humidifying for summer cooling, temperatures of 68

deg to 74 deg F and 50% relative

humidity are a frequent design average.

2. Heating and Humidifying for winter cooling, temperatures of 70 deg

to 75 deg F and relative humidity of 30%

to 35% are found most satisfactory.

3. Air Motion air velocity should average 4.57 to 7.6

meters per min measured 36” above the

floor.

4. Air Supply a. 5 cuft to 7-1/2 cuft of air per minute per

person (5-71/2 cuft/min/pers). In rooms

where smoking is not allowed

b.25 cuft to 40 cuft of air per minute per

person allowed in rooms where smoking

is permitted.

2.1 General

2.1.1 Definition of Air-

Conditioning

the simultaneous control of the

temperature, humidity, motion and

purity of the air in a confined space.

2.1.2 Functions or

Elements of Air-

Conditioning

1. Cooling and de-humidifying of air

2. Heating or humidifying of air

3. Cleaning of air or filtration

4. Circulation of air

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2. Split Type Air Conditioning

System

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC ACCU

AHU

EVAPORATOR

COMP.

CONDENSER

FCU

(FAN COIL

UNIT)

ACCU

(AIR CONDITIONING

CONDENSING UNIT)

2.0 HVAC

3. Window Type Air Conditioning

System

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2. Condensers

a) Air-cooled Condensers

used in unit and packaged-type air-

conditioners up to 3 tons

refrigeration.

b) Water-cooled Condensers

Double-piped Condensers:

2.4 Air-Conditioning

Equipment

2.4.1 The Refrigeration

Plant

1. Compressors

a) Piston Type or Reciprocating

Compressors

for tonnages up to 100 tons

b) Centrifugal Compressors

these are quieter, have fewer

vibration problems, require less

maintenance and with better

operating control

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

3. Evaporators

a) Shell and Tube Heat

Exchanger

similar in operation to the shell and

tube condenser. The refrigerant is

expanded into a shell enclosing the

tube through which the water flows.

b) Direct Expansion Coils (coils

containing the refrigerant itself)

This may either be installed in the

spray chamber so that the water

sprayed into the air comes into

contact with the cooling coils or the

air itself comes into direct contact

with the cooling coils, as in the

window type unit

Evaporative Condenser:

Shell and Tube Condensers:

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.4.4 Air Cleaning

Equipment

1. Filters

2.4.2 Cooling and De-

humidifying

Equipment

1. Water Sprays

2. Cooling Coils

2.4.3 Heating and

Humidifying

Equipment

1. Tempering Coils

contains steam and are used

to heating the air ie.,

preheaters and reheaters.

2. Water Heaters

used for heating the water

which will be used in the

spray chamber to add heat

and humidity to the air

a) Dry Filters consist of wire frames

enclosing felt, cotton or

sponge through which

the air is screened.

b) Viscous Filters consist of metal

deflecting plates or

screens coated with

viscous oil.

c) Water Sprays

d) Eliminator Plates consist of corrugated

galvanized iron sheets

placed 1-1/8” apart

which deflect the air flow

about 30 deg catching

the wet dust on the

surfaces

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.4.5 Air

Distribution

Equipment

1. Ducts

are usually of

galvanized sheet

metal, or aluminum

sheets, usually

rectangular in

section, depending

on the aspect

ratio*, although

circular ducts are

also used for high

velocity systems.

*Aspect Ratio – the ratio

of the long side to short

side; not to exceed 5:1

although 4 or 3:1 is

preferred.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2. Fans

a) Centrifugal fans (radial fans)

these are intended for moving air at

comparatively high pressures and

are commonly used in duct systems.

b) Propeller or axial fans

commonly used for wall exhausts

3. Air Outlets

these are made for two locations:

wall and ceiling.

a) Wall outlets include the

following:

Vaned outlets

Perforated grills

b) Ceiling outlets include the

following types:

Plaques

Perforated panels

Perforated ceilings

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2. Actuating or Operating

Devices

a) Dampers

These control the flow of air and are

in the form of louvers.

b) Control Valves

These are valves with variable

orifices which are moved by motors

to present smaller or larger

openings as directed by a

thermostat.

c) Relays

These are devices that use electrical

energy to amplify or convert the

power of a thermostat or other

controllers so that the resultant force

will be sufficient and adaptable to

operate a valve or damper.

2.4.6 Control Equipment

1. Sensing Devices

a) Humidistat

or Hygrostat is a controller, sensitive

to the amount of humidity in the air.

b) Thermostat

a controller which responds to

changes in temperature.

c) Pressure Regulators

are instruments sensitive to changes

in pressure. They may control a

single pressure or a differential

between two pressures.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

TYPE OF

SYSTEM

HEATING

MEDIUM

HEATING

DEVICE

METHOD

OF AIR

HANDLING

METHOD OF

DISTRIBUTION

1. Mechanical

Warm Air

Heating System

Air Furnace Ducts Registers

2. Steam Heating

System

Steam Boiler Pipes Radiators

3. Hot Water

Heating System

Water Water

Heater

Pipes Radiators

4. Radiant Panel

Heating System

1. Water

2. Air

3. Electricity

Water Heater

Furnace

Elec Heater

Pipes

Ducts

Wires

Ceiling or Floor

Ceiling

Ceiling

2.5 Heating Systems

2.5.1 Types of Heating

Systems 2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.5.2 Mechanical Warm Air

Heating System 2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.5.2 Steam Heating

System

2. Vacuum System (Two-pipe

Steam Heating System)

1. Air-Vent System (One-Pipe

Gravity System)

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2. Two-Pipe Hot Water Heating

System

1. One-Pipe Hot Water Heating

System

2.5.4 Hot Water Heating

System 2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.5.5 Radiant Panel

Heating System 2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

Capacity of Works, Project or

Plant The total horsepower of all engines,

motors, turbines or other prime movers

installed, whether in operation or not.

Compressor A mechanical device for the purpose of

increasing the pressure upon the

refrigerant.

Condenser A vessel or arrangement of pipes or

tubing in which vaporized refrigerant is

liquefied by the removal of heat.

Condemned Boiler or Unfired

Pressure Vessel A boiler or unfired pressure vessel that

has been inspected by the Building

Official and declared unsafe or

disqualified and power stamped or

marked designating its rejection.

2.6 Provisions in the

NBC Concerning HVAC

2.6.1 Definitions

Accidental Contact Any inadvertent physical contact with

power transmission equipment, prime

movers, machines or machine parts

which could result from slipping, falling,

sliding, tripping or any other unplanned

action or movement.

Air Conditioning The process of treating air so as to control

simultaneously its temperature, humidity,

cleanliness and distribution to meet the

requirements of the conditioned space.

Boiler A closed vessel for heating water or for

application of heat to generate steam or

other vapor to be used externally or to

itself.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

External Inspection An inspection made on boiler during

operation.

Guarded Shielded, fenced or otherwise protected

by means of suitable enclosure guards,

covers or standard railings, so as to

preclude the possibility of accidental

contact or dangerous approach to

persons or objects.

Internal Inspection An inspection made when a boiler is shut

down, with hand holes, manholes, or

other openings opened or removed to

permit inspection of the interior.

Liquid Receiver A vessel permanently connected to a

system by inlet and outlet pipes for

storage of a liquid refrigerant.

Locomotive Boiler A boiler mounted on a self-propelled track

locomotive used to furnish motivating

power for traveling on rails.

Crane Means a machine for lifting or lowering a

load and moving it horizontally, the

hoisting mechanism being an integral part

of the machine.

Duct A passageway made of sheet metal or

other suitable material not necessarily

leak tight, for conveying air or other gases

at low pressure.

Enclosed Means that the moving parts of a machine

are so guarded that physical contact by

any part of the human body is precluded

or prevented. This does not however

prohibit the use of hinged, sliding or

otherwise removable doors or sections to

permit inspection, lubrication or proper

maintenance.

Evaporation That part of the AC/refrigeration system in

which liquid refrigerant is vaporized to

produce refrigeration.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

Point of Operation That part of a machine which performs an

operation on the stock or material and/or

that place or location where stock or

material is fed to the machine. A machine

may have more than one point of

operation.

Portable Boiler An internally fired boiler which is self-

contained, primarily intended for

temporary location.

Prime Mover An engine or motor operated by steam,

gas, air, electricity, liquid or gaseous fuels,

liquids in motion or other forms of energy

whose main function is to drive or

operate, either directly of indirectly, other

mechanical equipment.

Process Machine An equipment designed and operated for

a specific purpose.

Low Pressure Heating Boiler A boiler operated at pressures not

exceeding 1.05 kgs/sqm with steam or

water temperature not exceeding 250ºF.

Machine The driven unit of an equipment.

Machine House An enclosure for housing the hoisting

mechanism and power plant.

Machine Parts Any or all moving parts of a machine.

Mechanical Works Plant Includes steam plants, internal

combustion engine plants, hydraulic

power plants, pumping plants,

refrigerating plants, air conditioning

plants, mill shops, factories, foundries,

shipyards, etc. containing any mechanical

equipment, machinery or process, driven

by steam, internal or external combustion

fuel, electricity, gas, air, water, heat,

chemicals or other prime movers.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.6.2 Boilers and Pressure

Vessels

1. Location of Boilers: a) Boilers may be located inside buildings

provided that the boiler room is of

reinforced concrete or masonry and that

the boiler room shall not be used for any

other purpose.

b) In case the main building is not made

up of fire resistive materials, boilers shall

be located outside the building at a

distance of not less than 3.00 m from the

outside wall of the main building and the

building housing the boiler shall be made

up of fire resistive materials.

c) No part of the boiler shall be closer

than one meter from any wall.

d) Fire tube boilers shall be provided with

sufficient room for removal/replacement of

tubes either thru the front or rear.

Refrigerant A substance which produces a

refrigerating effect by its absorption of

heat while expanding or evaporating.

Ton of Refrigeration The useful refrigerating effect equal to

12,000 BTU/hour; 200 BTU/min.

Unfired Pressure Vessel A vessel in which pressure is obtained

from an external source or from an

indirect application of heat.

Ventilation Process of supplying or removing air by

natural or mechanical means to or from

any space.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

5. Two check valves shall be

provided between any feed pump

and the boiler in addition to the

regular shut-off valve.

6. Where two or more boilers are

connected in parallel, each steam

outlet shall be provided with a non-

return valve and a shut-off valve.

7. Boiler rooms shall have at least

two separate exits.

8. In no case shall the maximum

pressure of an old/existing boiler be

increased to a greater pressure than

would be allowed for a new boiler of

same construction.

9. Each boiler shall have at least one

safety valve. For boilers having more

than 46 sqm pressure of water heating

surface or a generating capacity

exceeding 907 kg per hour, two (2) or

more safety valves shall be required.

2. Smokestacks whether self

supporting or guyed, shall be of

sufficient capacity to handle fuel

gases, shall be able to withstand a

wind load of 175 km per hour and

shall rise at least 5 m above the

eaves of any building within a radius

of 50 m.

3. Manufacturers/assemblers of

boilers/pressure vessels/pressurized

water heaters shall stamp each

vessel on the front head or on any

other suitable location with the name

of the manufacturer, serial number,

maximum allowable working

pressure, heating surface in sqm

and year of manufacture.

4. Boilers of more than 46 sqm

heating surface shall each be

provided with two means of feeding

water, one steam driven and one

electrically driven, one pump and

one injector.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

13. Upon the completion of the

installation, the Building Official shall

conduct an inspection and test, after

which a certificate of operation for a

period not exceeding one year shall be

issued upon payment of the required

inspection fees.

14. The Building Official shall notify the

owner in writing of the intended date of

the annual inspection at least 15 days in

advance. However, the owner may

request a postponement in writing of said

inspection and the Building Official shall

fix a date for inspection agreeable to both,

but not to exceed 30 days from the

intended date.

15. The owner or user of a boiler shall

prepare the same for inspection by

cooling it down blanking off all

connections to adjacent boilers, removing

all soot and ashes from tubes, heads,

shell, furnace and combustion chamber.

The owner shall assist the Building

Official by providing all labor and

equipment required during said

inspection.

10. Each boiler shall have a steam

gauge, with a dial range of not less

than 1-1/2 times and not more than

twice the maximum allowable

working pressure. It may be

connected to the steam space or to

the steam connection to the water

column.

11. Whenever repairs/replacements

are made on fittings or appliances,

the work shall comply with the

section on New Installation of the

Philippine Mechanical Engineering

Code.

12. After a permit has been granted

to install a boiler/pressure

vessel/pressurized water heater

upon payment of the installation

fees thereof, it shall be the duty of

the Building Official to make periodic

inspection of the installation to

determine compliance with the

approved plans and specifications.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

5. Where ducts pass thru walls, floors

or partitions, the space around the duct

shall be sealed with fire resistant

material equivalent to that of the wall,

floor or partition, to prevent the

passage of flame or smoke.

6. When ducts or the outlets or inlets

to them pass through fire walls, they

shall be provided with automatic fire

dampers on both sides of the fire wall

through which they pass.

7. Fire doors and fire dampers shall

be arranged to close automatically and

remain tightly closed, upon the

operation of a fusible link or other

approved heat actuated device,

located where readily affected by an

abnormal rise of temperature in the

duct.

2.6.3 Refrigeration and Air-

Conditioning

1. The temperature and humidity of

the air to be used for comfortable

cooling shall be maintained at 68-74ºF

effective temperature at an air

movement from 4.57 to 7.60 MPM

within the living zone.

2. Water from evaporators,

condensers and other machinery shall

be properly collected into a suitable

water or drainage system.

3. Ducts shall be constructed entirely

of non-combustible materials such as

steel, iron, aluminum or other

approved materials. Only fire retardant

lining shall be used on the inside of

ducts.

4. Access doors shall be provided at

all automatic dampers, fire dampers,

thermostats and other apparatus

requiring service and inspection in the

duct system.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

12. Refrigerant piping crossing a

passageway in any building shall not be

less than 2.3 m above the floor.

13. In a refrigerating system containing

more than 9 kgs, stop valves shall be

installed in inlets and outlets of

compressors, outlets of liquid receivers,

and in liquid and suction branch header.

14. Window type ACs shall be provided

with drain pipe or plastic tubing for

discharging condensate water into a

suitable container.

15. Window type AC installed on ground

floors of buildings shall not be less than

2.13 m from the ground.

16. Window type ACs shall be provided

with exhaust ducts if the exhaust is

discharged into corridors/hallways/

arcades/sidewalks etc.

17. Window type ACs installed along

corridors/hallways/above the first floor

shall not be less than 2.13 m above the

floor level.

8. Each refrigerating system shall be

provided with a legible metal sign

permanently attached and easily

accessible, indicating thereon the

name of manufacturer or installer, kind

and total number of kgs of refrigerant

contained in the system and field test

pressure applied.

9. In refrigerating plants of more than

45 kg refrigerant, masks and helmets

shall be used. These shall be kept in a

suitable cabinet outside the machine

room when not in use.

10. Not more than 136 kgs of

refrigerant in approved containers shall

be stored in a machine room at any

given time.

11. Where ammonia is used, the

discharge may be into a tank of water,

which shall be used for no other

purpose except ammonia absorption.

At least one gallon of water shall be

provided for every 0.4536 kg of

ammonia in the system.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

7. Piping carrying steam, hot water of hot

liquids shall not be embedded in concrete

walls or floors and shall be properly

insulated to prevent accidental scalding to

persons and to minimize heat loss.

8. Color coding of piping shall be as

follows:

a) Steam Division

High Pressure- White

Exhaust System – Buff

b) Water Division

Fresh water, low pressure – Blue

Fresh water, high pressure – Blue

Salt water piping – Green

c) Oil Division

Delivery – Brass or Bronze

Discharge – Yellow

d) Pneumatic Division

All piping – Gray

e) Gas Division

All piping – Black

f) Fuel Oil Division

All piping – Black

g) Refrigerating Division

Pipes – Black

Fittings – Black

2.6.4 Piping 1. Piping shall, as much as possible, run

parallel to building walls.

2. Grouped piping shall be supported on

racks, on either horizontal or vertical

planes.

3. Piping on racks shall have sufficient

space for pipe or chain wrenches so that

any single line can be

altered/repaired/replaced without

disturbing the rest.

4. Piping 100mm in diameter and above

shall be flanged. Smaller sized pipes

may be screwed.

5. Piping subjected to varying

temperatures shall be provided with

expansion joints.

6. Galvanized piping shall not be used for

steam.

2.1 General

2.2 Refrigeration

Cycle

2.3 Types of Air-

Conditioning

Systems

2.4 Air-Conditioning

Equipment

2.5 Heating

Systems

2.6 Provisions in

the NBC

Concerning HVAC

2.0 HVAC

2.0 HVAC

2.0 HVAC

2.0 HVAC

refrigeration

END

HEATING,

VENTILATION AND

AIR-CONDITIONING