Optimum use of fuel – Heating oil contains hydrogen which, on combustion, is turned into steam. If the exhaust gases from the combustion process are cooled, the steam contained in them condenses and the heat from the condensation process can be used. The flue gases must be cooled to below the so-called “dew-point temperature”, in order for them to condense. The dew-point temperature is dependent on the hydrogen content of the fuel and hence on the steam content of the flue gases. With extra-light (EL) heating oil the dew-point temperature is about 47 °C. By using the latent heat of condensation, the efficiency of a heating system can be significantly improved. In practice this results in the production of 0.5 to 1 l of condensate per kg of heating oil. Because of the relatively low temperature of between 45 and 50 °C of the resultant flue gases, flues for their removal can be made of plastic tubing.
Modern condensing boiler technology can therefore extract energy from the fuel being used in the most efficient way. This enables oil-fired condensing boilers to reach 98 % efficiency when measured against the higher heating value (gross calorific value) of the heating oil, a value which represents the physical limit of what is possible. A traditional boiler does not make use of this additional heat and it thus goes to waste; in these cases the energy contained in the condensate is discharged into the environment via the chimney or flue-pipe. Oil-fired condensing boiler technology thus achieves the highest efficiency with the lowest fuel consumption and minimum emissions.
Clean for the environment: low-sulphur heating oil is a quality fuel, which conforms to laid-down standards and which demonstrates several essential advantages over normal heating oil. It means that noxious substances in the flue gases are reduced to a minimum. Moreover the condensate does not need to be neutralised. That is why it is recommended by all the leading heating appliance manufacturers. Low sulphur heating oil is ideally suited to the requirements of condensing boiler technology and offers advantages for low temperature boilers as well. Low-sulphur heating oil burns very cleanly and makes for consistently good heat transfer in the boiler. This results in boilers which demonstrate continuously high levels of efficiency and a high degree of reliability. Low-sulphur heating oil will attract tax advantages in many countries as against conventional heating oils. With this, policy makers intend to encourage the use of low-sulphur heating oil and thus establish an important pre-requisite for the more widespread use of oil-fired condensing boiler technology. In addition oil-fired condensing boiler technology combines splendidly with solar-thermal energy. The solar collectors supplement the domestic hot water system and, depending on the design of the system, also contribute to heating the building.
