A direct vent fireplace is a prefabricated metal fireplace that employs a direct-vent combustion system. "Direct vent" refers to a sealed-combustion system in which air for combustion is drawn from the outdoors, and waste combustion gasses are exhausted to the outdoors. "Direct vent" does not simply mean that all gasses from combustion are vented to the exterior of the structure in which it is installed.[1][2]
The preassembled fireplace unit is made up of two main components: the outer housing, and the flue system.
Outer housingedit
The outer housing is the part of the fireplace unit that is installed in the framing of the building. The two main operational components are housed inside of it. The first key component within the outer housing is the firebox, which is surrounded on five sides by the outer housing, and on one side by the glass panel that faces towards the room. This is the space in which the fire burns during operation. Because of this, the gas burners (either natural gas or propane) are located inside of the firebox. To provide a more realistic look, imitation logs and ember material are placed on top of the burners. The ember material, which will not burn, is designed so that it will glow like real embers when heated. The firebox is designed to be smaller than the outer housing so that there is an empty space between the outermost walls of outer housing and the outer walls of the firebox. The empty space in between the firebox and the outer housing is the second important operational component of the outer housing. This space is filled with air from the interior of the room being heated and is used to add hot air to the room without the addition of exhaust gasses from combustion.[3]
Flue systemedit
The flue system is composed of two flues, the inner flue and the outer flue. The outer flue draws air into the bottom of the sealed firebox to allow for combustion. The inner flue draws hot exhaust gasses from the top of the sealed firebox and vents them directly to the outside of the structure through either an adjacent wall or roof.[4]
Operationedit
To begin the operation of the fireplace unit, the user must turn on the gas supply and ignite the burners. Once this is done, the unit will operate completely autonomously until the gas supply to the burners is shut off. While in operation, convection will cause the hot air in the firebox to rise to the top of the firebox. As the amount of hot exhaust gasses increases from the combustion process, the hot gas at the top of the firebox is eventually pushed out through the inner flue. At the same time, the removal of the exhaust gasses through the inner flue allows for relatively cold air to be drawn into the firebox through the outer flue.[5]
As the firebox heats up due to the operation of the burners, it radiates heat into the room through the porous glass face that separates the firebox from the inside of the room. At the same time, it transfers heat through the surrounding metal walls into the empty space between itself and the outer housing. This heat transfer creates a convection process inside of the empty space that is very similar to the one that takes place inside of the firebox. Built into the design of the room facing side of the unit are two vents, one at the top and one at the bottom. Once the air in the empty space begins to heat up, convection pushes this heated air further up in the chamber until it is eventually pushed out through the top vent. This phenomenon works in the same way to draw air in through the bottom vent. As the hot air is pushed out, space is emptied in the chamber behind the firebox, which then draws cold air in through the bottom vent.[6]
Both of these convection processes immediately begin to slow down, and eventually stop, as soon as the burners turn off.[7]
Efficiencyedit
Direct vent fireplaces are extremely efficient compared to a traditional fireplace and can operate at about 85% efficiency. Even a very efficient traditional fireplace only operates at about 15% efficiency. This is because most of the hot air generated by the fire travels up the chimney due to convection. A traditional fireplace can also draw hot air in from the room and expel it through the chimney, further lowering the efficiency. The design of the direct vent fireplace allows for such a high level of efficiency because of the sealed firebox. The sealed firebox only allows combustion gasses to leave the system and exit the building. Since it is sealed, no warm air from the room is able to be drawn into the firebox and expelled out of the building.[8]
Indoor air qualityedit
Direct vent fireplaces operate off of propane or natural gas, and are completely sealed from the interior of the building in which they are installed. Thus, no harmful byproducts are released into the room. They also release much less pollution into the atmosphere than a wood-burning fireplace.[2]
Referencesedit
^"RIS – Gesamte Rechtsvorschrift für Heizungsanlagen-Verordnung 2010 – Landesrecht Salzburg, Fassung vom 18.07.2015". bka.gv.at.[1]
^ ab. epa.gov. United States Environmental Protection Agency. Archived from the original on 2015-09-30. Retrieved November 10, 2013.
direct, vent, fireplace, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, scholar, jstor, no. This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Direct vent fireplace news newspapers books scholar JSTOR November 2016 Learn how and when to remove this message A direct vent fireplace is a prefabricated metal fireplace that employs a direct vent combustion system Direct vent refers to a sealed combustion system in which air for combustion is drawn from the outdoors and waste combustion gasses are exhausted to the outdoors Direct vent does not simply mean that all gasses from combustion are vented to the exterior of the structure in which it is installed 1 2 Contents 1 Construction 1 1 Outer housing 1 2 Flue system 2 Operation 3 Efficiency 4 Indoor air quality 5 References 6 External linksConstruction editThe preassembled fireplace unit is made up of two main components the outer housing and the flue system Outer housing edit The outer housing is the part of the fireplace unit that is installed in the framing of the building The two main operational components are housed inside of it The first key component within the outer housing is the firebox which is surrounded on five sides by the outer housing and on one side by the glass panel that faces towards the room This is the space in which the fire burns during operation Because of this the gas burners either natural gas or propane are located inside of the firebox To provide a more realistic look imitation logs and ember material are placed on top of the burners The ember material which will not burn is designed so that it will glow like real embers when heated The firebox is designed to be smaller than the outer housing so that there is an empty space between the outermost walls of outer housing and the outer walls of the firebox The empty space in between the firebox and the outer housing is the second important operational component of the outer housing This space is filled with air from the interior of the room being heated and is used to add hot air to the room without the addition of exhaust gasses from combustion 3 Flue system edit The flue system is composed of two flues the inner flue and the outer flue The outer flue draws air into the bottom of the sealed firebox to allow for combustion The inner flue draws hot exhaust gasses from the top of the sealed firebox and vents them directly to the outside of the structure through either an adjacent wall or roof 4 Operation editTo begin the operation of the fireplace unit the user must turn on the gas supply and ignite the burners Once this is done the unit will operate completely autonomously until the gas supply to the burners is shut off While in operation convection will cause the hot air in the firebox to rise to the top of the firebox As the amount of hot exhaust gasses increases from the combustion process the hot gas at the top of the firebox is eventually pushed out through the inner flue At the same time the removal of the exhaust gasses through the inner flue allows for relatively cold air to be drawn into the firebox through the outer flue 5 As the firebox heats up due to the operation of the burners it radiates heat into the room through the porous glass face that separates the firebox from the inside of the room At the same time it transfers heat through the surrounding metal walls into the empty space between itself and the outer housing This heat transfer creates a convection process inside of the empty space that is very similar to the one that takes place inside of the firebox Built into the design of the room facing side of the unit are two vents one at the top and one at the bottom Once the air in the empty space begins to heat up convection pushes this heated air further up in the chamber until it is eventually pushed out through the top vent This phenomenon works in the same way to draw air in through the bottom vent As the hot air is pushed out space is emptied in the chamber behind the firebox which then draws cold air in through the bottom vent 6 Both of these convection processes immediately begin to slow down and eventually stop as soon as the burners turn off 7 Efficiency editDirect vent fireplaces are extremely efficient compared to a traditional fireplace and can operate at about 85 efficiency Even a very efficient traditional fireplace only operates at about 15 efficiency This is because most of the hot air generated by the fire travels up the chimney due to convection A traditional fireplace can also draw hot air in from the room and expel it through the chimney further lowering the efficiency The design of the direct vent fireplace allows for such a high level of efficiency because of the sealed firebox The sealed firebox only allows combustion gasses to leave the system and exit the building Since it is sealed no warm air from the room is able to be drawn into the firebox and expelled out of the building 8 Indoor air quality editDirect vent fireplaces operate off of propane or natural gas and are completely sealed from the interior of the building in which they are installed Thus no harmful byproducts are released into the room They also release much less pollution into the atmosphere than a wood burning fireplace 2 References edit RIS Gesamte Rechtsvorschrift fur Heizungsanlagen Verordnung 2010 Landesrecht Salzburg Fassung vom 18 07 2015 bka gv at 1 a b Health Effects Burn Wise US EPA epa gov United States Environmental Protection Agency Archived from the original on 2015 09 30 Retrieved November 10 2013 Rumens Kurt Direct vent fireplace installation Patent Retrieved 2013 10 22 Wilhoite Murray Direct vent fireplace Patent Retrieved 2013 10 22 Kelly John 9 February 2010 How Fireplaces Work howstuffworks com Retrieved 2019 11 10 Wilhoite Murray Direct vent fireplace Patent Retrieved 2013 10 22 Kayne R What is a Direct Vent Fireplace wiseGEEK org Retrieved 2013 10 22 Senf Norbert The Hearth as an Element of the Sustainable House A Comparison of Emission Test Methods for New Clean Burning Wood Fired Masonry Fireplaces PDF Masonry Stove Builders Archived from the original PDF on 2013 11 13 Retrieved 2013 10 22 External links editFireplace BTU Calculator Archived 2015 11 20 at the Wayback Machine Retrieved from https en wikipedia org w index php title Direct vent fireplace amp oldid 1216563309, wikipedia, wiki, book, books, library,
