One of the most common heating types in Germany is oil heating. But how does an oil heater work? The individualization is done by choice of components. First of all, it makes sense to look at the central functional units of each system:
- Oil tank with the supply line
- heat storage
- circulating pump
- surge tank
- heat exchangers
- circulation piping
- Heat output devices
- exhaust execution
The basic operating principle of an oil heater is fundamentally the same for all heaters but can be modified and adapted by additional component and assembly methods. A classic example and required by law for modern oil heating systems is an operation with condensing technology. It has a unique exhaust gas technology, a condensing boiler, and individual components designed for this technology, such as the heat exchanger and a device for removing condensed water.
Eight steps as a functional basis
The question of how oil heating works can be summarized in eight main steps. The standardized process differs between older calorific value thermal baths, modern condensing boilers, and systems with simultaneous supply of drinking water only in details:
1. A pump transports the oil from the fuel oil tank into the burner.
2. A preheater prepares the oil and optimizes the ignition process
3. With one or more fine nozzles, the oil is injected into the combustion chamber
4. The oil and volatile oil vapor are ignited with an electric spark
5. The resulting heat is transferred from the heat exchanger to the
Heating water is routed 6. A pump transports the heating water into the circulation circuit
7. The expansion tank ensures the optimum line pressure adjustment
8. The exhaust gases are discharged, with condensing technology with an intermediate return stop
Oil heating with two heating circuits
The function of an oil heater can be extended in addition to the room heating on the parallel hot water preparation. By law, two utterly independent water cycles are prescribed. Accordingly, a hot water tank for drinking water must be installed. Depending on the heating model and design, some components, such as the heat exchanger, can operate both circuits. From the boiler output, the heat is generated for both circulation systems.
Not in all cases is a hot water supply integrated into the oil central heating system, the best solution. Long water flow paths require high pumping force to bring the required water pressure to each sampling point. On long transport routes also heat losses are unavoidable, which can be compensated only partially by a buffer memory.
Structure, components, and process
To illustrate the operation of an oil heater vividly, a chronological sequence from filling the tank to smoking the chimney is helpful:
The oil tank has a filler neck, through which it is filled. Metal tanks can be single-walled, plastic containers must be double-walled. An oil line leads the fuel oil to the burner, possibly assisted by a pump. When the fuel oil arrives in the boiler, it is brought to the optimum operating temperature. Nozzles inject the oil into the combustion chamber, where it burns with a blue flame in the so-called Blaubrenner. The heat exchanger absorbs the resulting heat. It transfers the temperature at the connection of the burner to the circulation system.
The circulation pump “pushes” the warm water into the circuit and, if necessary, into a buffer tank. The resulting during the combustion process air-gas mixture is derived in calorific value devices in the chimney. The operation of an oil condensing boiler is technically more complex. Here, a kind of second afterburning of the “trapped” soot gases is carried out. This requires the cooling of the return water. The resulting condensation water is collected and discharged through appropriate drainage pipes and trays. Only after the second combustion process, the exhaust gases are released through the chimney.