boiler
A boiler is used to convert chemically bound energy into thermal energy . The combustion chamber of the boiler is heated by a burner . All around the boiler chamber there are pipes in which a liquid, usually water , absorbs the thermal energy of the combustion and feeds it into the heating system.
In private households, boilers are mostly located in the basement. In most cases, this is also where the fuel is stored that is necessary to operate the respective boiler and thus generate heat. Occasionally, in new buildings, boilers are placed in the attic to save a chimney that extends over all floors .
Boiler types by fuel
| gas | Gas calorific value |
Heating oil | Fuel oil calorific value |
Biogenic fuels |
Solar thermal |
Heat pumps |
District heating |
electricity | Others |
|---|
| 2008 | ||||||
|
7.9 million gas boilers (41%) 2.7 million gas condensing boilers (14%) 6.0 million oil boilers (31%) 0.2 million oil condensing boilers (1%) 0.7 million biomass boilers (4%) 1 , 3 million thermal solar systems (7%) 0.3 million heat pumps (2%)
|
||||||
| February 2012 | ||||||
| Gas 49.4% Heat pumps 24.8% District heating 15.8% Electricity 1% Heating oil 2% Wood (pellets) 5.8% Other 2.4% | ||||||
| natural gas | District heating | Wood, pellets | Oil, liquid gas | electricity | ||
|
Natural gas 25.5% district heating 25% wood, pellets 20.3% heating oil, liquid gas 19.2% electrical power 6.5% heat pumps, solar energy 2.9% coal, coke 0.5% |
||||||
| gas | oil | Wood | Others |
|---|---|---|---|
|
Gas 251,887 buildings (15.2%) Heating oil 836,212 buildings (50.5%) Wood 199,246 buildings (12%) Other 22% Total: 1,656,864 buildings, with a total of 1,290,522 central heating systems for one building (77.9%) and 145,129 Individual furnace heating (8.8%) operated. |
|||
Gas boiler
Gas boilers gain thermal energy from the combustion of natural gas and transport the thermal energy via the heat carrier water. Outdated gas boilers often result in high heat losses and costs; Modern condensing boilers can lower energy costs and reduce pollutant emissions.
In contrast to fireplaces for solid fuels, no soot-fire-resistant chimney is required to operate gas-powered fireplaces . Due to the risk of sooting from condensing flue gas, however , low temperature and especially condensing boilers must be connected to a moisture- insensitive flue gas system .
Oil boiler
An oil heating boiler uses the fossil fuel oil to generate thermal energy through combustion. In addition to the boiler, a tank is required to store the fuel. The information on the flue gas system for gas-operated boilers also largely applies to oil-fired boilers.
Oil heating is becoming less important in Germany. Disadvantages are the increased expenditure for maintenance and fuel storage compared to gas boilers as well as volatile raw material prices and a slightly higher environmental impact.
Wood boiler or wood boiler heating
The wood boiler heating is one of the biomass boilers, logs or logs are used as fuel. Due to the high oil and gas prices, heating with biomass such as wood has once again become an alternative for many homeowners.
Pellet boiler
Pellet boilers are biomass boilers; wood pellets are usually used as fuel . Wood pellets are small pellets made of sawdust and, due to their compression and usually less moisture, have a higher energy value than normal logs.
Operating a pellet boiler requires a fuel storage room, but less space than would be the case when heating with split logs. The firing of the boiler with wood pellets is often done automatically via conveyor systems. Disadvantages see pellet heating # review
Boiler types according to purpose
Boilers are z. B. used for the following purposes:
- Steam generation , industrial steam engine
- Heat generation , heating and hot water preparation for buildings
- Waste incineration
Recording and avoidance of unnecessarily high energy consumption
To optimize heating systems, the entire chain of energy generation, from extraction to refining (in a refinery), transport, energy conversion and heat distribution, is often taken into account, many details are included. However, because the manufacturer's information (heat losses during operation) is used for heating, hot water generation and ventilation, downtime losses that occur in practice (which may not even be known in new buildings) are not determined and therefore not precisely determined. A detection of such heat losses would only heat meters in the forward fittings (heating and hot water) and matching with gas consumption meters or oil meters possible (see also efficiency ).
Clocking
Different assessments of the loss of readiness can be found in the specialist literature and in publications. Depending on the data source and fuel, from "well below 1%" up to 40% (for heating oil) or 50% of the total fuel consumption . The standstill losses are mostly caused by air purging of the burner chamber before and after the burner has run (to avoid deflagration of fuel residues). They arise during "cycling" (switching off the burner, resting time with cooling, starting the burner with an initially unstable flame and running time until the next switching off). Values of 30,000 cycles and more per year and of course just as many burner chamber cooling processes are not uncommon. On 365 days (including hot water preparation and storage) 1,800 hours of burner running time are compared to 6,960 hours of "standby" (= cooling down). Most of the heat losses from the thermally insulated boilers are then "heated out to the chimney".
The pulsing is usually caused because the heating water (the "return") flows back too quickly and too hot and then the burner - regardless of other room thermostat shutdowns - makes an emergency shutdown (because otherwise the heat generated could not be cooled down and dissipated). As soon as the water in the boiler has cooled down (switching time = hysteresis ), the burner starts up again and switches off again immediately. The associated regular cooling processes in the combustion chamber add up to considerable heat losses. One of the most common causes of cycling is explained in the article hydraulic balancing , which can be prevented with relatively little financial outlay and thus heating energy / heating costs can be saved.
With the regular measurement of the exhaust gas losses in accordance with the German regulation on small and medium-sized combustion systems , the exhaust gases from boilers are measured in regular operation . Losses during cooling are not recorded.
Optimus program
In the OPTIMUS program funded by the Deutsche Bundesstiftung Umwelt (DBU) , savings potentials for single and multi-family houses were determined in practice. The objects examined had the following unfavorable design on average:
- Overdimensioning of the heat generator design by about 80% based on the required building heating load (remedy: boiler with a "modulating burner" , i.e. a burner whose output can be reduced).
- Power oversizing of the pumps by three times, based on sufficient electrical utilization (remedy: speed-adjustable pumps)
- Overdimensioning of the standard radiator output by 70% based on the effective room heating load (remedy: hydraulic balancing ).
The countermeasures were (2003) comparatively inexpensive with costs of 2 to 7 euros per square meter of living space. Only the following measures were carried out:
- Installation and regulation of presettable thermostatic valves for flow limitation (hydraulic balancing)
- Adjustment or settings of the heating circulation pumps
- Setting the heating controls in order to achieve a larger switching hysteresis , i.e. H. the cycle is reduced or the time span between switching off and restarting the burner increases.
The success of the individual heating systems, which were improved in the OPTIMUS project, would result in savings potential of between 20,000 and 28,000 GWh of primary energy per year (for comparison: the Brokdorf nuclear power plant fed 11,360 GWh of electricity into the grid in 2010).
Combustion air
Modern condensing boilers usually draw the air required for combustion from a combined air-exhaust system . The most common design for smaller boilers are concentric double tubes. The exhaust gas is discharged through the inner pipe, the combustion air is supplied through the outer pipe. This enables the combustion air to be preheated, while at the same time the utilization of the calorific value is improved by cooling and condensing the flue gases.
The high-performance heat exchangers in condensing boilers often consist of fine fins that should generally be cleaned once a year. If the combustion air contains dust or other particles, more frequent cleaning may be required.
Even the smallest proportions of halogenated hydrocarbons in the combustion air lead to surface corrosion of metallic parts that come into contact with the combustion gases. In stainless steel may pitting occur. If the combustion air is taken from the installation room , free halogen compounds can come from the following sources, for example: CKW -containing paint strippers or adhesive removers , CFC -containing spray paints and adhesives, chlorine-containing disinfectants or chlorine bleach such as Javelle water , as well as vapors of hydrochloric acid .
Exhaust gas treatment
The flue gas cleaning by dedusting and flue gas scrubbers are in large heating systems state of the art , but are also available for smaller boilers below 50 kW. According to a study on the state of the art in particle separators, the efficiency of fine dust separation in systems with flue gas condensation alone would be low (in the range of 10 to 20%). Coarse fly ash particles , on the other hand, are usually deposited.
See also
- Condensing boiler
- Firing (gas firing, gas burner, oil burner, etc.)
- Combination heaters
Web links
Individual evidence
- ↑ Germany infographic at Meineheizung.de, private website
- ↑ PDF file available at: AGEB AG Energiebilanzen.eV ( Memento of the original from August 8, 2014 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , Energy consumption in Germany, data for the 1st quarter of 2012, last accessed in October 2012
- ↑ http://www.statistik.at/web_de/statistiken/energie_und_umwelt/energie/energieenergie_der_haushalte/index.html
- ↑ Domestic central heating systems with unknown fuel were defined as district heating
- ↑ Swiss Confederation, Federal Statistical Office ( Memento of the original dated November 16, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Buildings and apartments - data, indicators, buildings by type of heating and heating energy source
- ↑ Information on exhaust systems , Bruno Bosy
- ↑ H.Alt: System expenditure number ( prf file ( memento of the original from October 16, 2013 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this note .; PDF; 106 kB), energy certificate, Aachen University of Applied Sciences
- ↑ Kati Jagnow, Stefan Horschler: Brief description DIN V4701-10 BBL1: 2002-02 ( PDF file )
- ↑ Ansgar Schrode: Heating systems in low-energy houses , IKZ-HAUSTECHNIK, edition 9/1997
- ↑ Optimization where to start?
- ↑ Clocking the heating ( memento of the original from September 20, 2013 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Environmentally friendly and economical heating - but how?
- ↑ Jagnow, Wolff: OPTIMUS short report, page 3 ( Memento of the original from November 27, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 198 kB)
- ↑ The OPTIMUS project ( memento of the original from October 2, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Jagnow, Wolff: OPTIMUS short report, page 5 ( Memento of the original from November 27, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 198 kB)
- ↑ Jagnow, Wolff: OPTIMUS short report, page 7 ( Memento of the original from November 27, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 198 kB)
- ↑ Power Reactor Information System of the International Atomic Energy Agency IAEA (English)
- ^ Corrosion caused by halogenated hydrocarbons - Information sheet No. 1, March 2011, Federal Association of the German Heating Industry
- ↑ Michael Sattler: Dust separator for house fires (<50 kW) - systems available in Switzerland or about to be introduced - with practical information for chimney sweeps , (PDF file; 429 kB) ( Memento of the original from October 22, 2013 in Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Langenbruck 2007, at oekozentrum.ch
- ↑ Christoph Mandl, Ingwald Obernberger: Study on the state of the art of particle separators for domestic biomass combustion , IEA Bioenergy Task32 “Biomass combustion and Cofiring”, (German), (PDF file; 779 kB) ( Memento of the original from October 19, 2013 in Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
