Economizers for medium and large boilers

The Challenge 0

Firing boilers with natural gas offers a number of environmental benefits over other fuels, particularly other fossil fuels. However, efforts are still being made to increase efficiency and reduce emissions for natural gas-fired boilers. In the Guangyuan area of Beijing, China, the local energy company wanted to increase the efficiency of their Buderus natural gas boiler model GE615, 2 tons, by installing gas boiler economizers.

The solution

Their high efficiency, low pressure drop, and compact design make Airec heat exchangers the optimal solution for recovering waste heat from boilers, increasing their efficiency to almost 100%. Airec´s Chinese partner Guangzhou EastFirst Ltd, together with a local installation company, has successfully retrofitted Cross 30 to gas-fired boilers in the Beijing area.
Heat exchanger: 3 x Cross 30 (140 plates), copper-brazed in parallel

The result

The boiler operates at 75% load most of the time, releasing the flue gases at a temperature near to 200 °C.
The integration of Airec’s solution cools the gases to 78 °C while condensing 77 kg/h of their water content. This means close to 120 kW waste heat is recovered, and efficiency is increased from 86.5% to 97.6%.

Natural gas consumption is reduced by 83 000 Nm3/year, saving CO2 emissions of 143 tons/year. The payback time for this project is 1.5 years, well under the 10-year lifetime of the Cross 30 modules. In this project, every side of the Customer-Airec-Environment triangle is a winner.

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