BOILERS & BURNERS Modular or one-piece?


Condensing boilers that have been specifically designed for commercial settings offer consistent efficiency across all outputs over modular alternatives, argues Nick Guy.


Nick Guy www.bkbdboilers.co.uk


W


Managing director of BKBD Boilers


ith efficiency rates of up to 97%, commercial condensing boilers surpass conventional boilers, where efficiency


peaks at 78%. The approach has been to use the domestic model and scale it up for industry use, designed to adapt to the fluctuating heat loads of commercial buildings. If a module fails, the cascade operation guarantees the rest of the boilers keep running, ensuring unbroken heat supply. Also, most models allow for a simple integration into existing heating systems, while their design enables quick access for servicing. However, there are limitations on fuel


supply. Some go as far as supporting natural gas, LPG, light fuel oil and biodiesel – requiring servicing to switch between fuel types. In case of lack of fuel, the boiler system would shut down completely. Thinking ahead, although most modular condensing boilers are now hydrogen ready, models that can be operated with 100% hydrogen – generating zero CO2 emissions – are still in prototype stages. Furthermore, return temperatures have


to be closely monitored. Some cite 40°C when firing oil, but if the return drops, the output would drop with it to prevent the stack gases being too low. We often see high standing losses – for example 0.2% at 70°C flow – and a maximum of three passes, reducing efficiency and causing heat loss.


Rather than scaling up domestic


models for commercial applications, BKBD has developed a design, specifically for commercial and industrial sites. The pioneering four pass watertube design delivers maximum heat efficiency at an


impressive 107% efficiency. Patented in the UK and US, minimum return temperatures can be as low as 15°C on any fuel without efficiency loss. In addition, a BKBD has unlimited fuel options with ‘change on the fly’ between up to seven fuels – thanks to the capabilities of the boiler’s low NOx burner and micro- modulating control system. Both are included and make the boiler a turnkey solution with simple wiring and installation.


Minimising waste All BKBDs are 100% hydrogen ready. We have heated our HQ with hydrogen already and achieved 10:1 turndown and 2% O2 – increasing efficiency even further. Made from 316L stainless steel, BKBDs standing losses are at an impressive 0.06% at 90°C flow. Overall, customers have experienced typical energy savings of up to 25% with the same demand-based control management that modular heating systems provide. The control system provides the flexibility to regulate changes in total heating capacity, as well as adjust for variable seasonal heating needs. There is also the question of space. BKBDs up to 293kW are designed to fit through standard doorways. In addition, both small and large models can be installed vertically or horizontally – muting this argument between modular and


condensing boiler models. It goes without saying that condensing


boilers are more efficient than standard boilers where the site’s heating demand can be covered by a condensing boiler. However, when it comes to modular vs one-piece condensing boilers, efficiency rates vary between boiler models when looking at the flow temperatures at which they were measured. The official standard system operating


pressure and temperature is set at 80/60 flow and return. Given the properties of water, lower flow temperatures of e.g. 50/30 allow for maximum condensation and thus higher efficiency and maximum output. Manufacturers might test a boiler’s efficiency rate at 50/30, but in reality boilers run on 80/60. This is important, because the cited efficiency rate and heat output drops for some models at the standard temperature. Whereas BKBDs maintain the desired heat output and efficiency rates at 80/60 flow and return, lower flow temperatures (50/30) would increase the efficiency rate even further. To conclude, when investing in a


new heating system, it is essential to consider not only the immediate financial implications (arguably, they are substantial for either model), but also the consistency of efficiency levels as this impacts the timeframe for ROI delivery.


■


“It is not the strongest of the species that survives, nor the most intelligent that survives. It is the one that is


most adaptable to change.” Charles Darwin


In our uncertain environment, energy adaptability is key. When it comes to process heating, Babcock Wanson offers more choice and flexibility to achieve your decarbonisation goals, reduce your fuel bill and allow for energy diversification.


Babcock Wanson UK Ltd. 7 Elstree Way, Borehamwood, Hertfordshire WD6 1SA, UK Tel: 020 8953 7111 | info@babcock-wanson.com www.babcock-wanson.com


16 EIBI | APRIL 2024

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