The snowmelt system prevents snow and ice accumulation on sidewalks, terraces and roadways, or is more economical, only part of an area such as a 2-foot (0.61 m) pair - wide tire trajectory in the driveway or the center along the sidewalk along the 1.5 meters of the sidewalk, etc. They function even during storms so as to improve safety and eliminate winter maintenance labor including shoveling or plowing snow and spreading de-icing salts or sand traction (sand). The snowmelt system can extend the life of concrete, asphalt or below the paver by eliminating the use of salt or other ice decomposing chemicals, and physical damage from winter service vehicles.
The system is available in two broad types based on heat sources: heat of electrical and heat resistance from combustion or geothermal sources that are delivered hydronically (in fluid). In a way, an electric snow melting system requires less maintenance than a snowmelt system because there are minimal moving parts and no damaging agent. However, snow melting systems tend to be much more expensive to operate.
Most new snow melting systems operate in conjunction with an automatic activation device that will turn on the system when it detects deposition and freezing and turns it off when the temperature is above freezing. This type of device ensures the system is only active for a useful period and reduces energy wastage. A high-threshold threshold further improves efficiency when installed along with an automatic melting snow controller to temporarily disable the system after the slab has reached sufficient melt snow temperatures. Some building codes require a high threshold threshold to prevent energy wastage. The total environmental impact depends on the energy source used.
Video Snowmelt system
Operating costs
Operating costs vary by region, energy source (electricity, gas, propane, etc.) used and associated costs. The American Society of Heating, Refrigerating, and Air-Conditioning Engineers have standards intended to achieve satisfactory results and to minimize energy consumption from over-sizing or over-designing systems. Systems are typically designed to generate 70-170 BTUs per square foot using ASHRAE guidelines by region. The time to melt the snow from the surface varies by storm and how much power is designed by the system to produce.
Maps Snowmelt system
Snow melt system
The snow melt system consists of three basic components: heating cables, control units, and activation devices.
Heating cables are built to withstand harsh conditions to be suitable for outdoor use. Cables must be registered for UL standards by a National Recognized Testing Laboratory and many consist of single or double conductors with protective and/or sealing layers. Many cables are rated at 105 ° C (221 ° F) and produce 6-50 watts per foot. Power per area is determined by the distance of the heating element.
The control unit is usually a wall-mounted control panel and can be mounted in a NEMA enclosure. The control unit varies by technology using line terminal blocks and loads, relays, activation terminals, transformers, and electronic monitoring.
The hydronic snow melting system
Heating elements in hydronic systems are closed-loop tubing or modular thermapanel systems made of flexible polymers or synthetic rubbers that circulate hot water mixtures and propylene glycol (antifreeze). The liquid is heated to a temperature of 16 ° C (61 ° F) to 60 ° C (140 ° F) to warm the concrete/asphalt/concrete slab around it and melt the snow and ice. The mechanical system technology for hydronic snowmaking systems is based on the same technology as radiant heating systems.
The most important part of a successful tubular hydronic-based heating system depends on tube spacing and proper layout. It is advisable to put the tube in a spiral or winding pattern to help distribute the heat evenly. The specifications for distances will vary between manufacturers. The faster the snowmelting will require a shorter distance from the tubing, the typical distance is 6-8 ".Other key factor is the amount of insulation used under the slab.
The hydro tube thrown into the concrete slab creates an uneven heating pattern in the concrete causing uneven pressure to occur inside the concrete slab. The use of high-temperature fluid that enters a very cold slab creates a stress crack and possibly abrasion of a concrete surface. The proximity of adjacent tubes and a slowly controlled temperature increase will reduce the negative effects of tube-based systems. Another method is to keep the minimum slab temperature above freezing throughout the winter.
An alternative to pre-isolated tube-based systems, HDPE modular heat exchange themapanel units. The modular HDPE thermapanels are fitted mounted pedestal pavers (usually used on roof installations) in a modular grid layout between 23.5 "- 26" at the center. They can also be used with any type of ground mounted, cast in place of concrete or raised deck mounted paver, wood or PVC decking.
Like an electric snow melting system, the hydronic snow melting system must be installed inside or below the base surface material (sand). Ensure that the basecoat is well compacted with the right base material and meets the ICPI (International Concrete Paver Institute) or the paver manufacturer's guide before starting the tube or thermapanel installation. Uneven settlements can damage the system and provide structurally weak sidewalks. Tubing can be fastened with cable ties either with re-mesh, re-bar or clamped down insulation slabs. An isolated modular thermoplastic system does not require re-mesh or re-bar and is arranged in pre-connected lines to a compacted sub-base. When a modular thermapanel system is set under a concrete slab, re-mesh or re-bar may be required to be installed inside a concrete monolith.
Hydonic tubes should not be placed directly above solid rocks; this will cause the heating tube to conduct heat to the earth. The pre-insulated modular thermal system can be placed directly above the bedrock or the structural concrete foundation.
To meet most of the paver manufacturer's assurances and the ICPI (International Concrete Paver Institute) specifications, up to 1 "coating sand for the paver should be used and should not exceed a maximum of 1 1/2". This can be a challenge with tube and re-bar based systems because they typically require more than 1 1/2 "sand beds.Excess of sand will cause the paver to resolve over time.The sand used for the bed and the connection must be clean concrete sand, free from clay, dirt, or foreign matter and shall be in accordance with ASTM C-33.
The system of modular fluid thermal transfer devices, commercially known as ThermaPANEL, provides full heat exchange and even with all pavers or concrete areas as opposed to the distance required by tubular systems. Full coverage allows the use of lower temperature fluids that reduce operating costs and reduce the thermal impact of pavement structures thereby reducing the damage of the concrete surface. The surface also appears at the temperature and can be cooled faster.
The modular snowmobile system can also be used to collect solar thermal energy from the sidewalk on warm days for pond heating and domestic or industrial purposes. They can also be used to cool sidewalk surfaces, especially around swimming pools or on terraces mounted on paver roofs that get very hot because the paver is detached from the building thus creating a solar battery which in turn enhances the urban heat island effect in the immediate vicinity.
Activation tool
There are a number of activation devices used for snow smelting applications. Some activators are simple manual timers that enable the system to remain at a certain time period while others sense the temperature and humidity or only the temperature conditions to automatically activate the snowmaking system. Automatic devices can be installed in the air, mounted on sidewalks or ditches installed. High-end activation devices include customizable temperature trigger points, adjustable delay adjustment cycles, and enhanced remote activation. Activation device allows snowmaking system to run 100% automatic.
Self-adjusting heater tray cable automatically adjusts the amount of heat supplied so that only parts with temperatures well below the heated set point.
Careful sensor placement is important to have effective results when using this activator. Activated moisture sensors should be placed in locations where they will effectively collect moisture from blizzards and are relatively close to the area to be free of snow and ice. Temperature sensors are installed on the outside to feel the same temperature conditions as the surfaces to be experienced by the melting system. Other activators, such as timers or manual switches can be installed in convenient locations.
New installation
Installation of snowmaking system is carried out during road or road construction with cable or pipeline distance or modular thermapanel line layout based on system design.
There should be at least 3 "and max 4" substrates that cover the electric heating cables for new concrete applications. Concrete mixtures should not contain sharp stones as they may damage the cables. Concrete should be allowed to be installed for 30 days before the heating cord is turned on. For this reason, the best installation time is during the summer months. There is no practical way to use a power cord system with a paver mounted on the foot.
Tubing systems usually have tubes attached to structural inforcement which are then aligned in concrete slabs using cribs or standoffs. There is no practical way to use a pipe-based system with a segmented paver or paver mounted on the foot. The only type of hydronic system currently available commercially for use with a footrest, platform or ground mounted is a modular thermapanel type system.
System installation specifications under asphalt can vary between each manufacturer. The cable can be placed on the base surface (usually sand bed), and covered with sand 1/2 ". Asphalt then shovel to the heating cable and the base surface.
When installing hydronic tubes or thermapanel systems under asphalt, sand barriers that meet plant specifications should be placed over pipes or thermapanels and cold water should be pumped through the system to keep the plastic from melting.
Insulation under cables or pipes is recommended, but not necessary. A one-inch rigid insulation can be installed beneath the base surface, or it can be placed on the base surface and the heating cable can be secured above insulation.
Some installations involve two layers of bitumen. For this installation, the base layer of asphalt (1 "thick) is placed first.The heater cable is then installed and secured to the surface of the base layer After the heating cable is installed, the second layer of asphalt is placed over the heating cable and first layer, implanting the heating cable inside the plate.
Installing a snowmelt system under a brick paver is achieved by placing a heating cable on the base surface of more than 1/2 "of sand.The heater cable is then covered with 1/2" of sand and the paver is installed as usual on a sand bottom. When using a hydronic system, up to 1 "of bed sand should be placed over the thermapanel unit Tubing is not recommended for segmented paving applications due to the need for excessive sand bedding.
Installing retrofit
The retrofit installation is possible with the electrical system by cutting the 1 1 / 4 path to 1 1 /< sub> 2 "in and between 1/4" and 3/8 "widened to asphalt or concrete, inserting the cable and sealing the grooves with support bars and cork or special seals on the groove surface.
Portable snow heater for consumer
In recent years, heated melting mats have been available to retail consumers. The plug is a waterproof electrical outlet, and can be placed on sidewalks, driveways, stairs, wheelchair ramps, and loading docks.
This heated mat consists of two layers of slip-resistant rubber with an intervening heating element, and can melt snow and ice in hours or minutes (depending on the level of heat and snow altitude). The mat is on and off depending on the current weather conditions.
Important installations
- Elevated Central Artery, Boston (not used and destroyed)
- M4 toll road, West London (not used)
- Mount Schweitzer Road, Idaho
- Peter Lawwell's private residence, entrance
- the entry way of Updown Court, England
- Bill Gates House, entrance
- Public sidewalks in ReykjavÃÆ'k and Akureyri, Iceland
- the gates of Karl Johans and various public sidewalks in Oslo, Norway
- Public roads and sidewalks in the Netherlands, Michigan
- Public sidewalks in Oak Park, Illinois
- National Research Council stepped into the sidewalk, Saskatoon, Saskatchewan
- CN Tower, main pod roof (Toronto, Canada)
See also
- Hypocaust
- Interstate highway
- Snowmelter
- Solar Path
- Trace heating
References
- Woodson, R. Dodge. Radiant Floor Heating. New York: McGraw-Hill, c. 1999.
Source of the article : Wikipedia
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