When looking into a new boiler or upgrade investment, your financial plan should consider the operation costs in the coming years. Adding efficiency boosters such as economiser will reduce significantly the overall cost of your steam and hot water production for the years to come.
A boiler economiser, also called a flue gas heat recovery unit, is a heat exchanger fitted to a boiler stack. It captures waste heat from exhaust gases to preheat feedwater, reducing fuel consumption, improving boiler efficiency, and lowering operating costs.
Economisers use the energy of the boiler flue gases to preheat the boiler feed water. The overall boiler efficiency can be improved up to 10%. That is 10% off your fuel bill per year. This is the best investment you can make to lower the boiler operational costs.
The single stage economiser has individual fin tubes compression-fitted to the liquid manifold for ease of tube replacement requiring no welding. The large number of standard models provide combinations that work in applications with space constraints while still achieving maximum heat recovery. Flexibility allows specific engineering requirements to be met, such as fin spacing for fouling conditions and low gas pressure drops. The internal gas bypass can be used to temper the exiting gas for stack corrosion control or to maintain water temperature when too much heat is available.
The large number of standard models provide height and diameter combinations that work in applications with space constraints, while still achieving maximum heat recovery.
The Condensing Economizer saves fuel by preheating virtually any cool liquid stream (makeup water, wash water, hot water preheating, process, etc.) by capturing waste heat from a boiler stack. It has individual fin tubes compression-fitted to the liquid manifold for ease of tube replacement requiring no welding.
Combustion efficiency is one of the key aspects of the boiler efficiency and can vary considerably and can be improved to greatly contribute further to the fuel savings.
To have the most efficient combustion, exactly all oxygen is consumed and all fuel burned and the fuel-to-air ratio should be 9.7:1. This is theoretical “perfect combustion” In practice, however, for safety and maintenance needs, additional air beyond the theoretical perfect ratio needs to be added to the combustion process and this is referred to as excess air. A burner is typically set up with minimum 24-30% excess air. Higher excess air levels result in fuel being used to heat the air instead of transferring it to usable energy, increasing stack losses. Even though excess air is needed from a practical standpoint, too much excess air lowers boiler efficiency. On the other hand, reducing the amount of combustion air results in an excess of unburned fuel, and unburned fuel is a form of CO, is toxic and explosive.
Simple burner controls have the fan providing the excess air set up for the maximum load – high fire. If the air fan can’t vary its speed, the volume of the excess air will remain the same as if the burner is firing at full load, even when the burner modulates to low fire. The percentage of excess air is now way above 24% – 30% which makes the boiler losing more and more efficiency with the decreasing demand and dropping dramatically at low fire.
The most efficient combustion controls include a VSD on the air fan and O2 Trim, whereby the level of excess air in a boiler can be precisely managed resulting in optimum efficiency.
Continuous boiler surface blowdown heat recovery (BDHR) is the most effective method of purging destructive solids from any steam boiler system. The blowdown heat recovery systems will usually result in a payback in a few short months from fuel savings alone.
The BDHR automatically controls the surface blowdown to maintain the desired level of total dissolved solids (TDS) in the boiler, reducing the amount of blowdown to a minimum. It also recovers the heat from the hightemperature blowdown and transfers it to the incoming cold makeup water, maximizing boiler efficiency.
When looking at reducing operational cost and boosting the overall plant efficiency, there are easy options to consider. For example, by using valve and steam trap jackets and preventing heat losses through all your steam armatures. These losses can be considerable and minimising losses through proper insulation is cleaver and easy to do. The jackets are removable and re-attachable and allow quick access for operation and maintenance. It’s a smart investment and a constant saving.
What mark would you rate your business in terms of energy efficiency?
Whatever your answer is, you can still level up your business by using Ayvaz valve and steam trap jackets. They valve and steam trap jackets offer high performance with an ultra-thin structure. High-tech jackets could be three times thinner especially for the small sized products.
In case that an un-insulated globe valve (4”, DN 100) is used in an fluid system at 160 °C; it causes 1.199 watt energy loss hourly, this is equal to 629 m3 natural gas consumption and loss of 245 Euro annularly.
Whatever the size and working conditions of your products, we offer you the most appropriate solutions.
There is an aspect of boiler efficiency so called ‘In-service or Cycle efficiency’. It’s the allover efficiency of the operating stages of a boiler plant. Most of the plants only achieve 70 % – 75% of the planned 80% – 85% boiler efficiency.
Why the low efficiency? It is primarily due to frequent burner cycling. This can be caused by: installing a boiler that is too large for the heat/process load as a result of original over-sizing, building efficiency upgrades, boiler efficiency upgrades or a combination of all three. Oversized boiler/burner cycling is extremely inefficient as it boosts fixed losses such as radiation and convection that increase at the lower firing rates as a percent of full input.
By preheating feedwater with heat that would otherwise be wasted, a boiler economiser reduces the amount of fuel required to raise steam. This leads to significant energy savings and lower operating costs.
A boiler economiser improves thermal efficiency, reduces fuel costs, cuts greenhouse gas emissions, and extends boiler lifespan by maintaining consistent operating conditions.
Most modern and industrial boilers can be retrofitted with an economiser, provided there is enough space and compatible flue gas temperature. A technical assessment is recommended before installation.
Fuel savings depend on boiler size and usage, but economisers can typically reduce fuel consumption by 5–10%. Large industrial systems often see even higher savings.
Yes, by cutting fuel usage, a boiler economiser lowers carbon dioxide emissions, helping businesses meet energy efficiency targets and sustainability goals.
The payback period varies, but many businesses recover their investment within 1–3 years through fuel savings and lower energy bills.
Economisers require periodic cleaning to prevent fouling and ensure heat transfer efficiency. Routine inspections and proper water treatment help maintain performance and prevent corrosion.
Installation may require temporary boiler shutdown, but professional installation can minimise downtime. Many retrofits are completed during scheduled maintenance periods.
Yes, for most industrial and commercial operations, the fuel savings, reduced energy costs, and environmental benefits make a boiler economiser a cost-effective energy efficiency upgrade.
