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Information about Zone Damper

This article is about the architectural element. For other uers, see Damper (disambiguation).


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Opposed blade dampers in a mixing duct.
A damper is a valve or plate that stops or regulates the flow of air inside a duct, chimney, VAV box, air handler, or other air handling equipment. A damper may be used to cut off central air conditioning (heating or cooling) to an unused room, or to regulate it for room-by-room temperature and climate control. Its operation can be manual or automatic. Manual dampers are turned by a handle on the outside of a duct. Automatic dampers are used to regulate airflow constantly and are operated by electric or pneumatic motors, in turn controlled by a thermostat or building automation system.

In a chimney flue, a damper closes off the flue to keep the weather (and birds and other animals) out and warm or cool air in. This is usually done in the summer, but also sometimes in the winter between uses. In some cases, the damper may also be partly closed to help control the rate of combustion. The damper may be accessible only by reaching up into the fireplace by hand or with a woodpoker, or sometimes by a lever or knob that sticks down or out. On a woodburning stove or similar device, it is a usually handle on the vent duct as in an air conditioning system. Forgetting to open a damper before beginning a fire can cause serious smoke damage to the interior of a home, if not a house fire.

Automated zone dampers

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An opposed-blade, motor-closed, motor-opened zone damper. The damper is shown in the "open" position.
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Close-up of the motor connections. This damper can switch the electrical power to control additional "slave" dampers, minimizing the electrical load on the damper's control circuitry and power transformer
A zone damper is a specific type of damper used to control the flow of air in an HVAC heating or cooling system. In order to improve efficiency and occupant comfort, HVAC systems are commonly divided up into multiple zones. For example, in a house, the main floor may be served by one heating zone while the upstairs bedrooms are served by another. In this way, the heat can be directed principally to the main floor during the day and principally to the bedrooms at night, allowing the unoccupied areas to cool down.

the fully open and fully closed position of the damper as well as control of slaved dampers.]]

Zone dampers as used in home HVAC systems are usually electrically powered. In large commercial installations, vacuum or compressed air may be used instead. In either case, the motor is usually connected to the damper via a mechanical coupling.

For electrical zone dampers, there are two principal designs.

In one design, the motor is often a small shaded-pole synchronous motor combined with a rotary switch that can disconnect the motor at either of the two stopping points ("damper open" or "damper closed"). In this way, applying power to the "open damper" terminal causes the motor to run until the damper is open while applying power at the "close damper" terminal causes the motor to run until the damper is closed. The motor is commonly powered from the same 24 volt ac power source that is used for the rest of the control system. This allows the zone dampers to be directly controlled by low-voltage thermostats and wired with low-voltage wiring. Because simultaneous closure of all dampers might harm the furnace or air handler, this style of damper is often designed to only obstruct a portion of the air duct, for example, 75%.

Another style of electrically powered damper uses a spring-return mechanism and a shaded-pole synchronous motor. In this case, the damper is normally opened by the force of the spring but can be closed by the force of the motor. Removal of electrical power re-opens the damper. This style of damper is advantageous because it is "fail safe"; if the control to the damper fails, the damper opens and allows air to flow. However, in most applications "fail safe" indicates the damper will close upon loss of power thus preventing the spread of smoke and fire to other areas. These dampers also may allow adjustment of the "closed" position so that they only obstruct, for example, 75% of the air flow when closed.

For vacuum- or pneumatically-operated zone dampers, the thermostat usually switches the pressure or vacuum on or off, causing a spring-loaded rubber diaphragm to move and actuate the damper. As with the second style of electrical zone dampers, these dampers automatically return to the default position without the application of any power, and the default position is usually "open", allowing air to flow. Like the second style of electrical zone damper, these dampers may allow adjustment of the "closed" position.

Highly sophisticated systems may use some form of building automation such as BACnet or LonWorks to control the zone dampers. The dampers may also support positions other than fully open or fully closed and are usually capable of reporting their current position and, often, the temperature and volume of the air flowing past the smart damper.

Regardless of the style of damper employed, the systems are often designed so that when no thermostat is calling for air, all dampers in the system are opened. This allows air to continue to flow while the heat exchanger in a furnace cools down after a heating period completes.

Comparison to multiple furnaces/air handlers

Multiple zones can be implemented using either multiple, individually-controlled furnaces/air handlers or a single furnace/air handler and multiple zone dampers. Each approach has advantages and disadvantages.

Multiple furnaces/air handlers

Advantages:
  • Simple mechanical and control design ("SPST thermostats")
  • Redundancy: If one zone furnace fails, the others can remain working
Disadvantages:
  • Cost. Furnaces cost much more than zone dampers
  • Power consumption. Operating furnaces draw power whereas a zone damper only draws power while in motion from one state to the other (or, in some cases, a very small amount of power while holding closed).

Zone dampers

Advantages:
  • Cost.
  • Power consumption.
Disadvantages:
  • Zone dampers are not 100% reliable. The motor-to-open/motor-to-closed style of electrically operated zone dampers aren't "fail safe" (fail to the "open" condition).
  • No inherent redundancy for the furnace. A system with zone dampers is dependent upon a single furnace. If it fails, the system becomes completely inoperable.
  • The system can be harder to design, requiring both "SPDT" thermostats (or relays) and the ability of the system to withstand the fault condition whereby all zone dampers are closed simultaneously.

See also

A damper is a device that deadens, restrains, or depresses:

Damper may refer to:
  • Dashpot, a type of hydraulic or mechanical damper,
  • Shock absorber (British or technical use: damper), a mechanical device designed to dissipate kinetic energy

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Ducts are used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air. These needed airflows include, for example, supply air, return air, and exhaust air.
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chimneying, see Climbing technique.
For the Chimneys novels of Agatha Christie, see The Secret of Chimneys and The Seven Dials Mystery.


A chimney
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Variable air volume (VAV) is a technique for controlling the capacity of a heating, ventilating, and/or air-conditioning (HVAC) system. The simplest VAV system incorporates one supply duct that, when in cooling mode, distributes approximately 55 degree F supply air.
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air handler, or air handling unit and often abbreviated to AHU, is a device used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system.
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The term air conditioning most commonly refers to the cooling and dehumidification of indoor air for thermal comfort. In a broader sense, the term can refer to any form of cooling, heating, ventilation or disinfection that modifies the condition of air.
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trillion fold).]]

Temperature is a physical property of a system that underlies the common notions of hot and cold; something that is hotter generally has the greater temperature. Temperature is one of the principal parameters of thermodynamics.
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HVAC may also stand for High-voltage alternating current
HVAC (pronounced either "H-V-A-C" or, occasionally, "aitch-vak") is an initialism/acronym that stands for "heating, ventilation, and air conditioning".
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electric motor converts electrical energy into mechanical energy. The reverse process, that of converting mechanical energy into electrical energy, is accomplished by a generator or dynamo.
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A pneumatic motor is a machine which converts energy of compressed air into mechanical work. In industrial applications linear motion can come from either a diaphragm or piston actuator. As for rotary motion, either a vane type air motor or piston air motor is used.
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A thermostat is a device for regulating the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature. The thermostat does this by controlling the flow of heat energy into or out of the system.
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Building automation is a programmed, computerized, intelligent network of electronic devices that monitor and control the mechanical and lighting systems in a building. The intent is to create an intelligent building and reduce energy and maintenance costs.
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A flue is a duct, pipe, or chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors. In U.S.A. and for water heaters and modern furnaces, they are also called 'vents'; for boilers they are 'breeching'.
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weather is the set of all extant phenomena in a given atmosphere at a given time. The term usually refers to the activity of these phenomena over short periods (hours or days), as opposed to the term climate, which refers to the average atmospheric conditions over longer periods of
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Aves
Linnaeus, 1758

Orders

About two dozen - see section below

Birds (class Aves) are bipedal, warm-blooded, egg-laying vertebrate animals.
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fireplace is an architectural element consisting of a space designed to contain a fire, generally for heating but sometimes also for cooking. The space where the fire is contained is called a firebox or firepit; a chimney or other flue allows gas and particulate exhaust to escape
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Combustion or burning is a complex sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat or both heat and light in the form of either a glow or flames.
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Sources:

For cooking stoves, see .
“Stove Top” redirects here. For the brand of stuffing, see Stove Top stuffing.

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Vent may refer to:
  • Volcano, an opening in the Earth's surface which allows molten rock, ash and gases to escape
  • Deep sea vent, or "black smoker", a type of hydrothermal vent found on the ocean floor

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Fire is an oxidation process that releases energy in varying intensities in the form of light (with wavelengths also outside the visual spectrum) and heat and often creates smoke. It is commonly used to describe either a fuel in a state of combustion (e.g.
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Smoke is the airborne solid and liquid particulates and gases emitted when a material undergoes pyrolysis or combustion, together with the quantity of air that is entrained or otherwise mixed into the mass.
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HVAC may also stand for High-voltage alternating current
HVAC (pronounced either "H-V-A-C" or, occasionally, "aitch-vak") is an initialism/acronym that stands for "heating, ventilation, and air conditioning".
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A vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than standard atmospheric pressure. The Latin term in vacuo is used to describe an object as being in what would otherwise be a vacuum.
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Compressed air may refer to:
  • Pneumatics, the use of pressurized gases to do work
  • Breathing gas, often used in scuba diving, also to inflate buoyancy devices
  • Compressed air can also be used for refrigeration using a vortex tube
  • "Canned air" or gas duster.

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Shaded-pole synchronous motors are a class of AC motor.

Like a shaded pole induction motor, they use field coils with additional copper shading coils (see the illustration) to produce a weakly rotating magnetic field.
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volt (symbol: V) is the SI derived unit of electric potential difference or electromotive force.[1][2] It is named in honor of the Italian physicist Alessandro Volta (1745–1827), who invented the voltaic pile, the first modern chemical battery.
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alternating current (AC) is an electrical current whose magnitude and direction vary cyclically, as opposed to direct current, whose direction remains constant. The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of
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A thermostat is a device for regulating the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature. The thermostat does this by controlling the flow of heat energy into or out of the system.
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spring is a flexible elastic object used to store mechanical energy. Springs are usually made out of hardened steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication.
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spring is a flexible elastic object used to store mechanical energy. Springs are usually made out of hardened steel. Small springs can be wound from pre-hardened stock, while larger ones are made from annealed steel and hardened after fabrication.
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