Insulated pipes
Encyclopedia
Insulated pipes are widely used for district heating
and hot water supply in Europe
. They consist of a steel pipe, an insulating layer, and an outer casing. The main purpose of such pipes is to maintain the temperature
of the fluid in the pipes. A common application is the hot water from district heating plants. Most commonly used are single insulated pipes, but more recently in Europe it is becoming popular to use two pipes insulated within the same casing.
The insulating material
usually used is polyurethane
foam or similar, with a coefficient of thermal conductivity k=0.033-0.024 W/mK (thermal conductivity
). Outer casing
is usually high-density polyethylene (HDPE). Production of preinsulated pipes for district heating in the European Union is regulated by the standard EN253. According to EN253:2003, pipes must be produced to work at constant temperature of 130 °C for 30 years, keeping heat conductivity less than or equal to λ=0,033 W/mK. There are three insulation thickness levels.
Insulated pipelines are usually assembled from pipes of 6 m, 12 m, or 16 m in length, laid underground in depth 0.4–1.0 m. Efficient working life of district heating pipelines networks is estimated at 25–30 years, after which they need to be replaced with new pipes.
Four major producers of preinsulated pipes in Europe are located in Denmark
and Sweden
.
District heating
District heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating...
and hot water supply in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. They consist of a steel pipe, an insulating layer, and an outer casing. The main purpose of such pipes is to maintain the temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
of the fluid in the pipes. A common application is the hot water from district heating plants. Most commonly used are single insulated pipes, but more recently in Europe it is becoming popular to use two pipes insulated within the same casing.
The insulating material
Pipe insulation
Pipe Insulation is thermal or acoustic insulation used on pipework.-Condensation control:Where pipes operate at below-ambient temperatures, the potential exists for water vapour to condense on the pipe surface...
usually used is polyurethane
Polyurethane
A polyurethane is any polymer composed of a chain of organic units joined by carbamate links. Polyurethane polymers are formed through step-growth polymerization, by reacting a monomer with another monomer in the presence of a catalyst.Polyurethanes are...
foam or similar, with a coefficient of thermal conductivity k=0.033-0.024 W/mK (thermal conductivity
Thermal conductivity
In physics, thermal conductivity, k, is the property of a material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction....
). Outer casing
Casing
Casing may refer to:* Cartridge , shell enclosing the explosive propellant in ammunition* Casing , metal tube used during the drilling of a well* Casing , decorative molding surrounding door or window openings...
is usually high-density polyethylene (HDPE). Production of preinsulated pipes for district heating in the European Union is regulated by the standard EN253. According to EN253:2003, pipes must be produced to work at constant temperature of 130 °C for 30 years, keeping heat conductivity less than or equal to λ=0,033 W/mK. There are three insulation thickness levels.
Insulated pipelines are usually assembled from pipes of 6 m, 12 m, or 16 m in length, laid underground in depth 0.4–1.0 m. Efficient working life of district heating pipelines networks is estimated at 25–30 years, after which they need to be replaced with new pipes.
Four major producers of preinsulated pipes in Europe are located in Denmark
Denmark
Denmark is a Scandinavian country in Northern Europe. The countries of Denmark and Greenland, as well as the Faroe Islands, constitute the Kingdom of Denmark . It is the southernmost of the Nordic countries, southwest of Sweden and south of Norway, and bordered to the south by Germany. Denmark...
and Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
.
See also
- District heatingDistrict heatingDistrict heating is a system for distributing heat generated in a centralized location for residential and commercial heating requirements such as space heating and water heating...
- Heat conductionHeat conductionIn heat transfer, conduction is a mode of transfer of energy within and between bodies of matter, due to a temperature gradient. Conduction means collisional and diffusive transfer of kinetic energy of particles of ponderable matter . Conduction takes place in all forms of ponderable matter, viz....
- Heat transferHeat transferHeat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
- Heat transfer mechanisms
- R-valueR-value (insulation)The R-value is a measure of thermal resistance used in the building and construction industry. Under uniform conditions it is the ratio of the temperature difference across an insulator and the heat flux through it or R = \Delta T/\dot Q_A.The R-value being discussed is the unit thermal resistance...
- Specific Heat
- Thermal bridgeThermal bridgeA thermal bridge, also called a cold bridge, is a fundamental of heat transfer where a penetration of the insulation layer by a highly conductive or noninsulating material takes place in the separation between the interior and exterior environments of a building assembly .Thermal...
- Thermal contact conductanceThermal contact conductanceIn physics, thermal contact conductance is the study of heat conduction between solid bodies in thermal contact. The thermal contact conductance coefficient, h_c, is a property indicating the thermal conductivity, or ability to conduct heat, between two bodies in contact...
- Thermal diffusivityThermal diffusivityIn heat transfer analysis, thermal diffusivity is the thermal conductivity divided by density and specific heat capacity at constant pressure. It has the SI unit of m²/s...
- Thermal resistance in electronicsThermal resistance in electronicsThermal resistance is a heat property - and a measure of a temperature difference, by which an object - or material resist a heat flow...
- ThermocoupleThermocoupleA thermocouple is a device consisting of two different conductors that produce a voltage proportional to a temperature difference between either end of the pair of conductors. Thermocouples are a widely used type of temperature sensor for measurement and control and can also be used to convert a...