XI. BASIC MECHANICAL and HVAC SYSTEMSMODULE 29 – Building Mechanical Transport Systems

MODULE 30 – Building HVAC Systems

What are Mechanical Systems?

Mechanical Systems are building systems that applies the principles of physics and concerns machinery that provide important services for a structure’s functionality.

Mechanical Systems are any of the systems that provide essential services to a building such as heating, ventilation, air conditioning, vertical transportation or fire fighting.

Basic Mechanical Systems

• Systems that allow the ease of transport between spaces in a building; be it for human or equipment.

• Elevators

• Escalators

• Dumbwaiters

• Conveyors

• Chutes

Mechanical Transportation Systems

• Systems that control or improve the thermal and humidity conditions in a building environment.

• Heating

• Ventilation

• Air-conditioning

HVAC Systems

MODULE 28 –Building Mechanical Transport Systems

Mechanical Transportation Systems

ElevatorsElevators are moving platforms/cabins for carrying passengers or freight from one floor to another.

Considered as one of the most important innovations of the Industrial Revolution that gave way to modern building possibilities.

Two Types of Elevators

• Electric Elevators

• DC operated cabin consisting of a car that is mounted on guide rails, supported by hoisting cables, and driven by an electric hoisting machinery.

• Generally used for high rise structures.

• Hydraulic Elevators

• Consists of a car supported by a piston that is moved by or moves against a fluid under pressure.

• Generally used in low rise structures

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Electric Hydraulic

rail

car

guide shoe

plunger

motor

pump

buffer spring

Control Panel

Hoisting Machinery

Driving Sheave

Idle Sheave

Machine Beam

Hoisting Cable

Guide Rail

Traveling

Cable

Bulkhead

Elevator Car Safety

Landing

Top Car

Clearance

Counterweigh

t

Buffer

Bottom Car

Clearance

Elevator Pit

Hoistway

Door

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Electric Hydraulic

Basic Parts of an ElevatorCar Frame

•The structural steel frame of an elevator car to which are attached the platform, guide shoes, elevator car safety, hoisting cables and control equipment

Lantern

•A light, usually over the entrance to an elevator on each floor of a multi-storey building that signals the approach of the elevator.

Annunciator

•A signalling apparatus in an elevator car or at a landing that displays a visual indication of floor landings

Call Button

•A push button for requesting an elevator.

Door Interlock

•A safety device for preventing the operation of an elevator car unless the hoist way door is locked in the closed position.

Door Contact

•A safety device for preventing the operation of an elevator car unless its door or gate is fully closed

Parts of an Electrical Elevator

Shaft

•vertical passageway for car and counterweights.

Car

•a cage of light metal supported on a structural frame, the top member of which the cables, that carry the car, are fastened.

Cables

•are the means for lifting or lowering the car, usually 3 to 8 cables placed in parallel fastened to top of car by cable sockets passing over a motor driven cylindrical sheave to the counterweights.

Counterweights

•these are rectangular blocks of cast iron stacked in one frame which is fastened to the opposite ends of the cables to which the car is fastened.

Guide Rails

•are vertical tracks that guide the car and the counterweights.

Parts of an Electrical Elevator

Machine Room

• a room usually placed directly above the shaft in which the elevator machine is housed. It contains the motor-generator (MG) set which supplies energy to the elevator machine, the control board and the control equipment.

Elevator Machine

• turns the sheave that lifts and lowers the car.

Controls

• a combination of push buttons, contacts, relays, and devices, operated manually or automatically to initiate door opening, starting acceleration, retardation, levelling and stopping of the car.

Parts of an Electrical Elevator

•Main Brake

• mounted directly on the shaft of the elevator machine.

•Safety Switch

• is designed to stop an elevator car automatically before car speed becomes excessive. On over speed, the speed governor will cut off power to the motor and set the brake. This usually stops the car, but should speed still increase, the governor will actuate rail clamps mounted at the bottom of the car one on each side. This will clamp the guide rails bringing the car to a switch stop.

•Electric Final Limit Switches

•are located a few feet below and above safe travel limits of elevator car. If car over-travels, either down or up, these switches de-energizes the motor and sets the main brake.

• Oil or Spring Buffers

•are placed at the bottom of the elevator pit, not to stop a falling car, but to bring it to a partially cushion stop if the car should overshoot the lower terminal.

Safety Devices

Mechanical Transportation Systems

Dumbwaiters

Generally used for hoisting lightweight equipment, freight or loads. Commonly used in multi-storey food and health service establishments.

Mechanical Transportation Systems

Escalators

• are power driven stairways consisting of steps attached to a continuously circulating belt, used for moving passengers up and down between floors.

Escalators

• Width of Escalator = 32” and 48” (813mm and 1220mm)

• Angle of inclination = 30 degrees

• Length or run = variable

• Speeds = 90 fpm and 120 fpm (0.45m/s and 0.61m/s)

Typical Specifications

• Truss Frame

• Tracks

• Sprocket Assemblies/ Chain and Drive Machines

• Baluster

• Controllers

Parts of an Escalator Assembly

Parts of an Escalator

Truss

• a welded steel frame which supports the moving stairway equipment. It comes in 3 sections: the middle straight section maybe of any desired length to provide rises of different heights.

Tracks

• are steel angles attached to the truss on which the step rollers are guided thus controlling the motion of the steps.

Sprocket Assemblies, Chains, and Drive Machines

• provide the motive power for the unit. An emergency brake located on the top sprocket will stop a loaded escalator safely in the event of a break in the chain.

Parts of an Escalator

Controller

• consists of contactors, relays and a circuit breaker. Usually located near the drive machine, an emergency stop button wired to the controller and placed in or near the escalator, will stop the drive machine and apply the brake. Key operated control switches, at the top and bottom newels, will start, stop, and reverse the direction of travel of the stairway.

Handrail and Balustrade Assembly

handrail guide

longitudinal cording

canvas layers

inside balustrade

Rubber-covered

handrail

Mechanical Transportation Systems

Moving Walkways (Walkalators)

•While escalators are used to transport people vertically, electric walks are used to transport people horizontally (or semi-horizontally) at any inclination from 0 deg. to 15 deg.

Moving Walkways

Mechanical Walkways

•Groceries and shopping centeres

•For exhibit halls, where management desires that persons move smoothly through or pass a particular area without stopping or boarding.

•For airport terminals.

Common Application

•Standard width = 27” and 36”

•Speeds = 120 fpm and 180 fpmTypical Specifications

•Horizontal or level

•Bi-level

•Overpass installation

•Underpass installation

Types of Installations

Types of “Walkalators”

Automated Inclined Walkways

• Any of various forms of mass transit, as moving sidewalks or automated driverless vehicles, used for shuttling people from one space to another in an inclined surface.

Moving Walkways

• A power-driven, continuously moving surface, similar to a conveyor belt, used for carrying pedestrians horizontally or along very low inclines.

MODULE 28 –Building HVAC Systems

What are HVAC Systems?

HVAC Systems

• are systems that simultaneously control the temperature, humidity, motion and purity of the air in a confined space.

Functions or Elements of Air-Conditioning

• Cooling and Dehumidifying of air

• Heating or Humidifying of air

• Cleaning of air or Filtration

• Circulation of air

Air Conditioning StandardsCooling and Dehumidifying

• for summer cooling, temperatures of 68 deg to 74 deg F and 50% relative humidity are a frequent design average.

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.

Air Motion

• air velocity should average 4.57 to 7.6 meters per min measured 36” above the floor.

Air Supply

• Cu.ft. to 7-1/2 cu.ft. of air per minute per person (5-71/2 cu.ft./min/s). In rooms where smoking is not allowed

• 25 cu.ft. to 40 cu.ft. of air per minute per person allowed in rooms where smoking is permitted.

Types of Air Conditioning SystemsC

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Air

Con

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Air Conditioning System consists of the following:

• A method of cooling, a refrigeration plant

• An Air Handling Unit (AHU) equipped with filters, spray, cooling coils.

• The air distributing equipment composed of ducts, fans and air outlets

• The necessary manual or automatic controls

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conditioning system that consists of the following:

• Air Conditioning Condensing Unit

• Fan Coil Unit

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environmental cooling appliance that applies the principles of refrigeration cycle.

• The system is generally used as a system exclusive to a small space.

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Centralized Air Conditioning System

• All-Season Centralized Air Conditioning System consists of the following:

• A method of cooling, a refrigeration plant

• An Air Handling Unit (AHU) equipped with filters, spray, cooling coils.

• The air distributing equipment composed of ducts, fans and air outlets

• The necessary manual or automatic controls

Split Type Air Conditioning System

• Air conditioning system that consists of the following:

• Air Conditioning Condensing Unit

• Fan Coil Unit

ACCU

AHU

EVAPORATOR

COMP.

CONDENSER

FCU

(FAN COIL

UNIT)

ACCU

(AIR CONDITIONING

CONDENSING

UNIT)

Window Type Air Conditioning System

• A stand-alone

environmental cooling

appliance that applies

the principles of

refrigeration cycle.

• The system is generally

used as a system

exclusive to a small

space.

Basic Parts of an HVAC System (Cooling)

Refrigeration Plant

•Compressors

•Condensers

•Evaporators

Cooling and

Dehumidifying Equipment

•Water Sprays

•Cooling Coils

Air Cooling Equipment

•Dry Filters

•Viscous Filters

•Water Sprays

•Eliminator Plates

Basic Parts of an HVAC System (Cooling)

Air Distribution Equipment

• Ducts

• Fans

• Centrifugal Fans

• Axial Fans

• Air Outlets

• Wall Outlets

• Ceiling Outlets

Control Equipment

• Sensing Devices

• Humidistat

• Thermostat

• Pressure Regulators

• Actuating or Operation Device

• Dampers

• Control Valves

• Relays

Accessories