Bill Sinclair, technical director, Adveco, considers the latest developments in commercial

condensing boiler technology and how this can help meet the needs for sustainability and lower the total cost of ownership

address the heating demands of their large buildings? With the majority of national infrastructure currently ‘on gas’ and delivering half of UK’s non-transport primary energy needs, gas fired boilers remain a preferred option for the provision of commercial heating. Increasingly stringent legislation to reduce carbon emissions and hazardous air pollutants is driving the specification of systems that are based on high efficiency condensing boilers, or a hybrid approach that combines these boilers with heat pumps to provide low carbon, effective heating.


Reducing the cost of business critical heating

From restaurants and hotels, to leisure facilities, schools and university accommodation the needs are increasingly universal for large application, very efficient and low emission heating. As an independent provider of heating systems, identifying technology concepts that will address sustainability is only half the battle, we also recognise a need to reduce cost of ownership. Space savings, ongoing supply reliability to simplified control and maintenance are all means to reduce costs and provide peace of mind when investing in a business- critical heating system.

Whether limited by existing structures in a refurbishment, or reducing cost in a new build, saving space is an important consideration. But when a system demands more than 300kW output there has been little option other than to build a costly frame and implement a design incorporating the necessary wall hung boilers in cascade until the system’s needs are met. By which point you effectively have a floor standing system that negates the space advantages of a wall hung boiler. For this reason, some will consider a floor standing alternative, they are after all

aced with balancing the business-critical need for space heating against stricter legislation, how can UK commercial organisations better

relatively low cost and can supply high loads. The problem is that such appliances offer a single fan, gas valve and heat exchanger which means there is no system redundancy. That makes for false economy when it comes to delivering a space saving, consistent 24/7/365 heating system. We would advocate a modular cascade concept that takes full advantage of the compact size afforded by condensing natural gas or LPG boiler technology, with low water content heat engines, built-in redundancy and no need for an expensive framework to convert wall hung boilers to floor standing. Adveco’s MD boiler range, for instance, can be used to create a cascade of up to eight 280kW units, each combining four 70kW heat engines pre-stacked in a single, elegant casing. This approach can provide more than 2200kW while occupying minimal plant room floor space and assuring clearance for maintenance. The need for, and cost of a frame is immediately negated, and issues of limited headroom are quickly resolved. A high maximum run pressure, up to 11 bar, makes it highly suitable for large, high pressure applications.

Of course, while built-in redundancy is advantageous, the supply reliability should not hinge on redundancy systems but features that are designed to prolong the life of the appliance. Condensing boilers, by their very nature need to be tolerant of acid condensate. An easy to access, refillable, neutralising limestone bed is truly advantageous and can dramatically affect the lifespan of an appliance. Typically, new condensing boilers will be fitted with a heat exchanger made from a non-ferrous metal, usually stainless steel, to also counter corrosion. Today, we would recommend heat exchangers constructed from a continuous, non- welded run of titanium-stabilised stainless steel. This approach reduces weak points and offers improved strength and corrosion resistance at high temperatures for long periods of time, reducing the chance of failure while ensuring high capacity heat transfer.

Each heat exchanger also needs to be able to communicate, enabling load balancing across adjacent exchangers, providing built-in redundancy as well as improved reliability and longevity as a result of more uniform wear. Integrated system control not only allows for intelligent maintenance self-check of all primary appliance components and functions, but with incorporated Modbus communication and alarm output can assist with BMS integration. As a result, condensing boilers can meet the demand for reliability and efficiency for lower cost of ownership.

Meeting commercial sustainability goals

uThe Adveco MD range of high eciency condensing boilers are designed to provide a high capacity and reliable soluon to a building’s central heang demand


We can easily demonstrate the cost saving functionality of high efficiency condensing gas boilers, but what of the air quality and sustainability of the technology?


Balancing the cost of sustainability and commercial heating demands

uHeat exchangers constructed from a connuous, nonwelded run of tanium stabilised stainless steel are recommended

Designed so that the highest efficiency is at the low end of the firing range, condensing boilers typically operate at 94-95 per cent combustion efficiency. A high efficiency pre-mix burner can achieve ideal combustion efficiency of up to 107 per cent (net)/98 per cent (gross) reducing energy costs and producing low emissions. With low CO and NOX emissions a heating system built around a high efficiency condensing boiler (Class 6 appliance) easily satisfies the requirements of the Energy-related Products (ErP) directive.

Correctly sized and professionally commissioned, a cascade system with high efficiency pre-mix burner can provide a high 1:20 modulation ratio. This, along with built-in cascade control ensures that efficiencies are maximised no matter the heating load of the building. With the input of the boiler easily altered to closely match the heating load, the system is better able to derive as much heat out of the exhaust gases as possible. This efficient reuse of heat results in low flue gas temperatures allowing for the use of standard 80-160mm diameter plastic flue pipe (PP). PP is efficient, environmentally friendly and significantly cheaper than stainless steel, offering a cost-effective and space saving alternative in terms of pipe run.

Whilst arguments continue to rage regarding the validity of gas for a low carbon future, the reality is that for the foreseeable future our national infrastructure will continue to remain heavily reliant on the provision and improved use of gas. For commercial projects that face the most stringent legislation and oversight, high- efficiency condensing boilers remain a realistic and effective means of meeting the demands for improved sustainability. This could be as part of a hybrid systems where continuous low grade heat from the heat pump works alongside the fast responsiveness of the gas boiler to top up heating at electricity peak demand times avoiding the requirement for higher carbon emitting generators. It could well be through the introduction of green gas with its lower carbon footprint. Crucially, gas continues to offer considerable economic advantages in terms of operational costs for built assets. Read the latest at:

uAdveco’s exclusive heat exchanger features a three pass design with large bore, circular tube cross secons that reduce the collecon of debris


limited by exisng structures in a refurbishment, or reducing cost in a new build, saving space is an important consideraon

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