Oil heating
As oil heating refers to a heating , in the heat by the combustion of fuel oil , for example. B. Heating oil EL ( E xtra L light (liquid)) is generated.
The use of oil heating is heavily criticized because it is the most harmful form of heating. In 2019 there are still around 8.7 million households in Germany that use oil for heating. In Sweden, on the other hand, there are practically no oil heating systems anymore thanks to CO 2 pricing .
An oil heater is not to be confused with an oil stove . This only heats the room in which it is located.
Oil burners with and without auxiliary energy
A distinction can be made between:
- Oil combustion without auxiliary energy
- Oil combustion with auxiliary energy
The oil heating is used for space heating and hot water preparation. There are the boiler variants standard, low temperature and condensing boiler . According to the heating ordinance, standard boilers may no longer be re-installed; they still exist. The state of the art are condensing boilers; they are more efficient than low temperature boilers. All variants are available as wall units and as floor units.
Oil burner without auxiliary energy
The flash point of extra light heating oil (EL) is 55 ° C. So the oil does not burn without increasing the temperature. With this type of burner, the oil is brought to the temperature necessary for its combustion in a special furnace (usually a so-called oil furnace ) without the supply of auxiliary electrical energy solely through the heat of combustion. Ignition takes place with a pilot flame and a special wick or a (solid or liquid) special oil stove lighter.
The burner used for this is called an evaporative burner . These stoves are usually used as single fireplaces in apartments. They have a built-in tank into which the oil has to be topped up with a special jug, or there is a motorized oil replenishment system in which a pump delivers the oil into the furnace (also known as central oil supply ).
Since, unlike when burning wood or coal, no ash has to be removed, oil stoves were seen as a convenient alternative to the stoves that had been common up to now, especially in the 1950s and 60s, and were installed in many old buildings. There are also ovens in which the oil supply is regulated by a thermostat so that a set room temperature is maintained. With the increasing use of central heating , oil stoves are now rarely found.
Oil burner with auxiliary energy
In the case of combustion with auxiliary energy, the soot-free combustion is supported by preheating the oil (usually electrically) and with the aid of a fan . The actual ignition is carried out by an ignition device with a high-voltage spark. This type of oil burner is the most widely used. A distinction is made between devices for generating heat and for generating steam or electricity.
Considerably higher outputs can be achieved in a much smaller space than with evaporative burners. The oil is injected into the combustion chamber by means of a pump through a nozzle . The resulting, ignitable oil-air mixture (the oil mist) is ignited by an ignition spark. Further combustion then takes place without further ignition. The progress of the combustion is monitored by flame monitors.
The problem is the immediate heating of the nozzle assembly in order to preheat it in the case of a cold start without prior rinsing: If the oil carries solid components from storage tanks, the high heating power (usually 100 W when cold, with PTC thermistors less when the nozzle assembly is hot) is in the labyrinth The initially cold nozzle assembly is burnt and clogs the oil flow to the nozzle.
Exhaust system
Heating oil contains sulfur particles, among other things . As long as the dew point in the exhaust system is not undershot, there is no permanent risk of corrosion.
If the dew point is not reached, the flue gas produced during the combustion and the water vapor present produce sulphurous acid . Therefore, the materials of the boiler and flue system must be particularly corrosion-resistant when using standard heating oil . Used stainless steel or with condensing boilers and plastics . If only low-sulfur heating oil is used, there is no need to use corrosion-resistant materials for the boiler and flue system. '' Heating oil EL '' differs from '' Heating oil EL low-sulfur '' in terms of its maximum permissible sulfur content. According to DIN 51603 Part 1, EL heating oil may contain a maximum of 1000 mg / kg sulfur since January 1, 2008, and EL low-sulfur heating oil a maximum of 50 mg / kg.
Ecological and financial aspects
The oil price was largely stable (around USD 20 / barrel) in the 1990s. From January 2001 to August 2006 it quadrupled to $ 78. In July 2008 it hit an all-time high of over USD 140; then it fell below $ 40. The reasons for the drop in prices were an economic crisis that began at that time in many industrialized countries and increased oil production in the USA, where oil shale fields are exploited by means of fracking .
Petroleum is a carbonaceous fuel, the combustion of which accelerates climate change . As part of the energy transition, a switch from oil heating to heat from renewable energy sources is sought; Politics and the renewable energy sector call for a “change in heat”. The 'Energy Efficiency Incentive Program' (APEE) of the Federal Environment Ministry has been subsidizing heating replacement based on solar thermal energy, biomass or heat pumps since January 1, 2016; the Kreditanstalt für Wiederaufbau (KfW) grants low-interest loans. In Austria, modern heating oil condensing boilers have again been heavily subsidized by the federal and state governments since January 1, 2015.
In early 2013, Denmark banned the installation of boilers that run on oil or natural gas in new buildings across the country . From 2016, the new installation of oil burners or gas burners in existing buildings is also prohibited, provided that district heating is available.
Renewable energies as an alternative to oil heating
The current state of the art certainly allows a predominant supply from the energy forms sun, wind and / or water. A mix of energies from photovoltaics, small wind turbines and / or smaller hydropower systems as well as solar thermal systems is fed into an existing heating system.
The amount of energy that cannot be used or stored directly as electricity is fed to a large water reservoir. This then serves as a store for the generated thermal energy, which can be fed to the heating system during the day. Systems that work with a combination of photovoltaics, wind and / or water power are very responsive, as natural energy peaks from sun and wind can be converted directly into a large amount of energy of several kWh. The solar thermal part of such a system works in parallel and thus also generates thermal energy from solar power.
Web links
Individual evidence
- ↑ Süddeutsche Zeitung, 8.7 million households still heat with oil , October 2, 2019
- ↑ Christian Stichler: When the truck drives with sawdust. tagesschau.de, October 6, 2019.
- ↑ www.bafa.de
- ↑ BAFA: Replacing heating systems with simultaneous improvement in energy efficiency , accessed on October 5, 2016.
- ↑ Energy-efficient renovation - supplementary credit 167 , accessed on October 5, 2016.
- ↑ Welcome to your funding agency for oil heating systems. ( Memento from April 27, 2015 in the Internet Archive ) On: HeizenMitOel.at.
- ↑ www.energiezukunft.eu ( memento of June 29, 2017 in the Internet Archive ), accessed on June 15, 2017