Martin Cooke, Technical Director at EOGB Energy Products Ltd, discusses how to improve the efficiency of oil heating installations, the crucial role of servicing and the future challenges that burner manufacturers face.
Industry figures show that oil is still very much in demand and a viable heating option in rural and off-grid locations.
Oil installations take up little space internally within a property and, when compared to other fuels, it gives an excellent heat release-to-cost ratio. In fact, according to the Sutherland Tables, oil is now cheaper than natural gas and the price of kerosene has fallen by around 30% in the past two years.
Oil installations also allow the homeowner the flexibility to choose who and where to purchase fuel from should there be a price fluctuation.
How installations can be improved to save fuel and reduce emissions
One major area to observe when investigating fuel savings is system design:
We can also look at combustion efficiency of the boiler:
If we look at oil-fired boilers, most manufacturers will state a CO2 level of 12% in their installation and commissioning literature. This is because for heating oil to combust, it takes one part fuel and around 15 parts air and in a perfect situation combustion would be complete and the products of combustion would be CO2, N2, H2O and of course heat. As perfect situations don’t exist, the CO2 is starved of O2 and we always get CO as a consequence. This is why excess air is required to be introduced into the combustion calculation – otherwise we would have CO2 of 15% and the burner would then be producing black smoke. Therefore, we add excess air to keep the combustion complete, hence the manufacturer’s figure of 11-12% CO2.
On the other hand, we must also be observant of excess air, as too much decreases efficiency and some of the useful heat is simply taken away within the flue gases. We also see this in LPG installations where recommended CO2 levels are around 10%. This is slightly higher than if we were using natural gas, but again it’s a balancing act to obtain complete combustion and keep CO to a minimum, yet still be as efficient as possible.
The importance of servicing oil and LPG appliances is vital and cannot be overlooked as both fuels can soot and cause dangerous situations if not maintained. When looked after on an annual basis they are both excellent forms of heating in both new and established homes and also commercial/industrial premises.
Servicing not only helps users save money on their fuel bills by having the heat exchangers cleaned and the combustion efficiencies checked, but good engineers will also be able to ensure trouble-free operations by examining all areas of the boiler and heating system. They can also advise users on possible issues that may occur in future and how they can safeguard this. Unfortunately, many users simply overlook servicing and see it as an unnecessary cost, which can be a decision they live to regret when their forgotten boiler lets them down during a particularly cold spell of weather!
Looking to the future
Whilst LPG and oil has been affected in recent years with the renewable market taking a small share that was once mostly dominated by oil and LPG bringing up the rear, it still has a positive future.
The biggest challenge ahead is not the renewable impact but forthcoming NOx reductions and how this is going to be managed by burner manufacturers. The target NOx levels of 120 mg/KWh rolling out in 2018 for standard oil-fired yellow flame burners is very challenging, so blue flame oil-fired combustion will probably take its place. The recirculating blue flame combustion burner head can achieve NOx emissions below the threshold and will hopefully enable oil-fired heating systems to still be a valuable part of the heating industry for many more years to come. With modulating oil blue flame burners becoming a viable reality in the coming years, efficiencies will be greatly improved, especially when used in conjunction with OpenTherm controls.
LPG installations with low NOx burner designs will also continue to play a part in the heating industry for the foreseeable future, despite the current trend shift and manufacturer’s renewable product launches.