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adapting to new technologies and approaches

2021 – Adapting to new technologies and approaches

The UK’s construction industry is familiar with adapting to new technologies and approaches to provide the latest and most efficient responses for creating better buildings.  2020, however, was unprecedented, but what does this mean for 2021? Looking forward, key trends within the industry include Covid-19 care, greener response sand efficient use of property space.

Coronavirus has attacked every corner of the UK, impacting the majority of businesses and therefore the wider economy. Despite vaccines, Covid-19 is now something we all must learn to live with, it has accelerated change and requires a re-evaluation of how buildings are conceived and used. As a specialist in the provision of commercial heating and especially hot water, Adveco is well versed in the design of systems to support the maintenance of hygiene within their buildings, critical for the ongoing prevention of the spread of Covid-19. There has never been a greater need for access to wash stations. Scientists have proven washing hand in warm, soapy waters for more than 20 seconds can reduce the spread of Coronavirus more efficiently than hand sanitisers. Additionally, hot water (at a minimum of 60°C) needs to be readily available for cleansing of materials and surfaces to prevent the spread further. With these requirements comes a need for more efficient systems capable of meeting these increased demands to be incorporated into commercial buildings. With the demands of maintaining a safe two-metre distance, space has become even more valuable. The hospitality sector is already struggling with the challenge of balancing revenue losses from reduced covers and are looking at how to create alfresco spaces to adapt to this new normal. Packaged plant rooms offer companies a means to use minimal space whilst still maximising efficient systems, freeing up valuable internal spaces or making use of dead spaces which are not customer friendly. This is also a fast, relatively low impact method for refurbishing hot water systems.

Despite all the chaos of Covid-19, it also brought into razor-sharp focus the effects of pollution. This was all too obvious when the world stopped for a moment and the effects of pollution decreased and allowed the environment to thrive. It proved to be a rallying cry for decarbonisation in 2020 and will continue to create headlines throughout 2021 and beyond. It remains a core focus for the construction and HVAC industry that will continue to strongly push for more wide-reaching frameworks to deliver eco-friendly technology and buildings to meet the challenging goal of achieving Net Zero by 2050.

Through exclusive technical partnerships and our in-house design function, Adveco can quickly adapt to these changing needs and help innovate products and systems to directly address the evolving challenges of decarbonising commercial buildings. We recognise that there is no single technology that delivers the entire answer, but there is no doubt Air Source Heat Pumps (ASHP) will play an important part, as will new green gas technologies towards the end of the decade.  This makes hybrid system approaches all the more valid for supporting the near-term transition of commercial organisations to a more sustainable track that reduces their building emissions and operational costs.

The Adveco 2021 Product Guide Now Available

Hot water and heating specialist Adveco, has published its latest Product Guide for 2021 (PDF). This handy booklet provides a complete overview of Adveco’s current portfolio of commercial hot water and heating products. With the Government’s pledge to deliver net-zero by 2050, the commercial sector faces an increasing challenge to address the carbon emissions from buildings. The recent sixth Carbon Budget put the scale of the challenge into perspective, calling for a 78% reduction in carbon emissions by 2035 if we as a nation are to meet this long-term net-zero commitment.

Whether planning a new build or refurbishing existing buildings, Adveco provides a broad choice of appliances, controls and ancillaries for the design and manufacture of bespoke applications. Supporting the drive to a more sustainable future, Adveco offers an ever-expanding range of renewables; from its long-term provision of solar thermal systems to award-winning boxed Heat Recovery Units, and the latest commercial-grade air source heat pumps.

Wherever a project is located, Adveco can support with the optimal technology; from glass-lined water heaters for hard water areas to corrosion-resistant stainless-steel alternatives for soft water conditions, and renewables that address the limitations of regional climates.

With access to the latest hot water and heating technology, we can ensure your application is provisioned with highly efficient, low-emission appliances, that offer the highest quality, robust construction to ensure longevity and best value investment.

The Adveco 2021 Product Guide provides an easy reference for a range of boilers, buffers and thermal stores for heating projects. It also incorporates the A.O. Smith range of condensing gas and electric water heaters, all supported by Adveco calorifiers, plate heat exchangers and immersions for hot water systems. Also discover the advantages of Adveco offsite construction, providing complete prefabricated plant rooms for heating and hot water systems.

All Adveco’s products are supported by 50 years of industry expertise as the independent provider of application and system design, bespoke manufacture and aftersales service and support. All supplied at a quality only a specialist manufacturer can deliver.

Download the brochure today

UK needs to cut emissions by 78% by 2035 to meet net-zero

Under the original Climate Change Act, the UK pledged to cut net emissions by 80% by 2050. Now, it will need to deliver a 78% reduction by 2035 if it is to meet its long-term net-zero commitment. That is according to the Climate Change Committee (CCC), which has published its Sixth Carbon Budget for the period between 2033 and 2037.

The CCC described the budget as the toughest yet with chief executive Chris Stark saying that the UK will need to decarbonise at a faster pace in the next 30 years if the net-zero target is to be met. Stark explained that the Committee has deliberately opted to ‘front-load’ decarbonisation – more will need to happen in the 2020s and the earlier half of the Sixth Carbon Budget period than in the latter half and the 2040s. Heat, and the broader decarbonisation of buildings, is one of the major priorities identified by the CCC which has based its calculations on a scenario in which 40% of the emissions reductions needed will be delivered using pure-technology solutions.

The new recommendations will see heat supply drastically transformed from its current reliance on natural gas if the country is to decarbonise all aspects of the UK’s infrastructure and economy. The budget has set a mandate for fossil fuel boiler installations to end across the UK entirely from 2033, with fossil fuels phased-out from heating in public buildings by 2025 and in commercial buildings by the following year. It added that these stricter targets to phase out higher-carbon technologies in public buildings would also support a government aim of realising a 50% reduction in emissions by 2032. The 2033 date has been set to take account of the typical 15-year turnover of boiler stock, while also allowing for the scaling-up of supply chains to deploy heat pumps at a mass scale.

The recommendations aim for 37 per cent of public and commercial heat demand to be met by lower-carbon sources as of 2030.  According to the CCC, heat pumps should cater for 65% of the predicted need, 32% of heat should be provided by district heating systems, whether low or high-temperature supply, with a further 3% from biomass by the end of the current decade. By 2050, CCC estimates that 52% of heat demand should be met by heat pumps, 42% from district heat, with hydrogen boilers covering the remaining 5% of national demand.

One caveat, however, was that since the dates operate alongside the deployment of low-carbon heat networks and planned regional rollouts of hydrogen conversion of the gas grid, the phase-out outlined may not apply in any areas designated for these alternatives. This makes a nod to a net-zero that derives balance between pure hydrogen systems and electrification, both delivering decarbonisation of heating. It also highlights the danger of supporting one technology and ignoring another when the pace of development is so much steeper and will continue to be so as we move towards 2050. To this end, the CCC is using what it describes as a ‘balanced pathway’ scenario upon which to base its calculations and that its delivery will require ‘systems change’ and a ‘whole economy approach’ to decisively meet the UK’s legal target of fully eliminating and offsetting carbon emissions by 2050.  Under this ‘decisive’ decarbonisation plan, the CCC has warned that a sizable majority of change must be made within 15 years.

Talk to Adveco about how we can help you create more sustainable heating and hot water applications for your buildings.

Space To Develop Hot Water & Heating

Space To Develop Hot Water & Heating

How relocating heating and hot water systems in commercial buildings can drive real value from underutilised space…

The most valuable asset any business or organisation has is space, space to grow, develop and drive advantage. Within the built environment the drive for more space is a balancing act between granting applicable and preferably comfortable space for those using the building and meeting the infrastructural and systemic needs of operating the building.

There typically has to be some kind of give in the drive for creating or freeing up useable space if that activity impacts on the necessary systems, in particular heating, cooling, lighting and water.

Hotels are a great example of this drive to reclaim usable space. The hospitality industry is one of the most competitive there is. Hotels are continually fighting with the competition to offer the most affordable rates, the best amenities, and the most outstanding guest services — all while also making a profit. The easiest way to charge more for a room is by adding space to it, or by adding more rooms in total. Either way that is going to help improve the bottom line. The same goes for restaurants, where maximising floor space means more tables. Whilst hoteliers and restaurateurs will look to every square centimetre of their properties for opportunities to maximise revenue, other organisations will have very different drivers. Consider schools, where larger class sizes have increasingly driven a demand for teaching space. How many schools have had to surrender playing fields to locate portacabin style classrooms which are obviously not ideal?

This brings us to the kinds of underutilised or wasted ‘dead’ space in and around buildings. Internal space is potentially incredibly valuable, so leveraging external space to free it up can be truly advantageous. The question is what can be given up to makes such gains? The simple answer might be your HVAC plant.

Plant rooms, or boiler houses as they were known, vary from purpose-built to jury-rigged spaces used to accommodate heating and hot water systems. Basements are typically repurposed in older commercial buildings, whilst it is not unusual to find them tucked in amongst other rooms creating a mixed-use setting. Wouldn’t it be advantageous to separate such building services and relocate them away from those using the building whilst improving the efficiency of the system for a host of benefits including lower operational costs and reduced emissions?

Simply upgrading to a new gas condensing boiler or electric water heater can deliver notable efficiency improvements over models from just 10 years ago, and today’s modern appliances pack that into much more compact, space-saving formats. So, you could gain greater capability from a smaller footprint in your plant room, and potentially reclaim a few square meters. But what if you could reclaim the entire plant room?

Refurbishing plant to a new location may sound drastic, but that needn’t be the case. Increasingly the construction industry has embraced the idea of offsite construction, creating modular units or systems that are pre-installed and ready for relatively quick and simple connection once delivered to a site. The process streamlines a construction programme along with offering numerous savings as site work is dramatically sped up. Now, this process can be as easily applied to refurbishment projects as it is to new build. All you need is an underutilised space. For many commercial buildings that means flat roofs, yards or car parks, spaces that are inexpensive to adapt, require low to no maintenance and have either been ignored or are underused.

With the proliferation of car ownership, it might at first seem unlikely that the car park is being underused. But the drive to encourage walking, cycling and car-sharing has had an impact, and developers who have previously pushed for more open parking space than ever before are now being challenged to repurpose some of that space. In terms of Identifying functional opportunities to better leverage this space, the siting of plant fits the bill. Turing over just one or two car spaces can have a dramatic impact on the capability of heating system, providing enough square meterage to easily accommodate a mid-sized packaged plant room offering, for example, a boiler cascade and heat exchanger assembly. Or the space could be used to locate Air Source Heat Pumps (ASHP) that drive system sustainability whilst lowering CO2 emissions.

Relocation to flat rooftops is especially valuable. This is truly ‘dead space’ for most buildings, but it provides a broad opportunity to relocate heating and hot water plant safely and more securely. A simple crane lift is all it takes to locate a prefabricated plant room, and these can be of considerable size and complexity should the roof space be large enough to accommodate. Additionally, the space lends itself to locating hybrid systems that integrate renewable and sustainable technologies. We have already mentioned the use of ASHPs, and a rooftop placement not only typically supplies unimpeded airflow, the noise, though relatively low, now becomes almost unnoticeable to those on the ground.

Flat roofs are also perfect for the installation of solar thermal systems, where a framework is constructed to align the collectors for optimal energy collection. That energy is then transferred to the building’s water system. One of the biggest threats to the efficiency of a solar thermal system is the heat loss between the collector and hot water storage, which results from potentially long pipe runs from the roof to the plant room. By locating the plant room on the roof, pipe run is minimised as are thermal losses, so you get more energy for your investment.

These are just a few examples of where Adveco’s application design, system prefabrication and expertise in hybrid and renewable technology can help maximise underutilised space. Modern, high-efficiency systems deliver new versatility for addressing changing demands of the building whilst still reducing operational expenditure on energy and helping drive actual sustainability within an organisation.

If your business or organisation is looking to

Talk to us today or read more about our renewables and packaged plant room systems.

Adveco packaged plant room for low carbon hot water.

Adveco Packaged e-Hot Water System For Low Carbon Hot Water

  • Reduce operational costs by offsetting up to 70% of the energy required by equivalent sized systems. Dramatically reduces CO² emissions
  • Unique low heat intensity specification reduces the threat of scale formation
  • Built-in backup for system resilience, ensuring consistency of service

Hot water and heating specialist Adveco, offers commercial businesses with large hot water demands but space limitations a complete, highly-efficient, low carbon response with its Packaged e-Hot Water System.

This prefabricated all-electric water heating system brings together Adveco’s FPi-9 Air Source Heat Pump (ASHP), an Adveco 200L GLC indirect preheat tank, and Adveco 200L GLE direct electric water heater to provide reliable high-temperature water in a convenient, packaged system housed in a compact GRP housing.

Bill Sinclair, technical director, Adveco says:

“The Packaged e-Hot Water System leverages all the advantages of off-site construction to provide a standardised, resilient, environmentally friendly, low carbon, hot water system that helps reduce both a building’s energy consumption and operational costs across its lifetime.”

Adveco’s Packaged E-Hot Water System makes particular use of the FPi-9 ASHP to provide the system preheat from 10°C to 50°C, supplying 70% of the DHW load.

Offsetting 70% of the energy requirement means the Packaged e-Hot Water System can demonstrate a 47% reduction in energy demands and CO² emissions for the same output of 500,000 litres of hot water each year when compared with a similar direct electric-only system. The reduced energy demand also means operational savings can be added to the capital savings secured during the design, supply, and installation phases.

A completely new specification that lowers the heat intensity, without detrimental effect to the demands for hot water, means the Packaged e-Hot Water System is also more resistant to scale, reducing maintenance demands.

The GLE also has an additional 6kW immersion heater to provide backup in case of failure of the lead heat source for sites where hot water is business critical. The Adveco designed control system monitors the heat sources, and in the case of failure, it can automatically activate the backup system.

Adveco’s Packaged e-Hot Water System is ideal for a wide range of commercial properties with regular hot water demands such as restaurants and boutique hotels, offices, schools, and light industry. The system is also perfect for both new builds or refurbishment where space is at a premium.

Adveco Packaged E-Hot Water System

Adveco Packaged E-Hot Water System for low carbon hot water.

Technical Features

  • FPi-9 ASHP supplies 9kW at 7°C outdoor temperature
  • Nominal 18kW of heat is input to the domestic hot water (9kW ASHP and 9kW electric element)
  • Sized to meet the typical needs of a larger facility and can supply 314 l/peak hour. Based on a 12-hour daily operation and one peak hour, this equates to 1370 litres of hot water per day
SSI 1500 Stainless Steel Indirect

Is a Calorifier Right for My Project?

A calorifier is a commercial-grade indirect-fired water heater that provides hot water in a heating and hot water system.

It is designed for projects requiring large volume storage of water at high temperature, but rather than using a burner, the water is heated by heat exchanger coils containing liquid from another heat source, such as a boiler.

In a typical application, the hot water directly heated by a gas or electric boiler passes through the calorifier and is used, via heat exchange, to heat up the cold water in a separate system of pipework. This does mean that a calorifier cannot react as quickly to demand as a direct-fired water heater, however, with the calorifier working as a buffer and storing the hot water, it reduces the operational demand placed on the boiler. With the boiler no longer required to work as hard to meet the domestic hot water needs (DHW) of a building, energy is saved, costs are reduced and emissions fall.

With the increased efficiency of modern condensing gas boilers, having a dedicated hot water boiler to heat the calorifier is no longer a requirement as they can easily supply heat to both the calorifier and the heating system. The compact Adveco MD range of gas condensing boilers, for example,  are both high capacity and can be arranged in cascade to scale to provide both heating and, with an indirect calorifier, the DHW needs of a wide variety of commercial projects. It must be noted that when space heating is not required, such as during the summer months, the boiler will still be required to provide heat for the hot water system.

Another advantage of the indirect approach to heating is that due to the transferral of heat through the walls of the heat exchanger element the two fluids do not mix. This allows for more options in terms of the external heat supply and introduces a range of renewable technologies that use other fluids for heat transfer including solar thermal collectors and Air Source Heat Pumps. At Adveco, these options are supported by a variety of calorifiers. The Stainless Steel Indirect (SSI) range, for example, is supplied with a single high-output internal heat exchange coil at low level to serve as an indirect calorifier in DHW installations. For more complex and renewable-based systems, the Stainless Steel Twin-Coil (SST) range offers a pair of independent internal heat exchange coils to serve DHW systems. Each high-output coil can be used with a separate heat source, enabling effective integration of renewable technologies or multiple heat sources, or alternatively can be combined to increase the heat transfer capacity from a single high-output source.

Also, by separating the supplies you reduce the risks of external contamination, a build-up of scale in hard water areas or the corrosive effects of soft water.

Calorifiers are also simple to install. Since there is no burner, there is no need for the gas supply to be directly connected to the appliance and the is no requirement for a flue.

As with any hot water application, understanding the relationship between storage and recovery, and correct sizing is extremely important for efficient and cost-effective operation. Integrating a calorifier within a hot water system gives you a number of design options, as a larger calorifier means the boiler can be smaller, or the reverse if the existing system has a large efficient boiler. Understanding the hot water demand is critical. If demand is not so great, then using a larger calorifier can lead to unnecessary capital and ongoing operational expenditure. Go too small and the storage could prove inadequate and the system will not achieve its operational requirements.

Attaining the correct balance of demand and efficient, cost-effective supply is what ultimately defines a successful system, whether it be for a hotel, hospital, school, office or leisure facility. Each will have their own parameters to be met, and Adveco specialises in providing the widest range of calorifiers, boilers and renewables to meet the bespoke needs of any project.

The patterns of hot water usage and recognition of periods of peak demands often make sizing a complicated process, with many systems overcompensating and, by being oversized become more costly and less efficient. At its simplest, a commercial system should hold an hour of hot water output in storage, but the function of the building, its population and activities will adjust requirements, for example, where hospitals will typically exhibit a 24/7 demand for hot water, schools and offices may be limited to just 7½ hours per day. In some refurbishment scenarios, we will also see a physical limitation of space available for DHW storage, in which case a system will put more demand on the boiler or renewable to increase the output for preheating, reducing the required size of calorifier.

If there is an availability of space, or a prefabricated packaged plant room approach can be used to relocate plant to previously unused space – such as a rooftop or car park – there is an opportunity to incorporate multiple calorifiers and thereby divide the total storage demand. This approach not only provides system resilience, but for commercial sites that exhibit predictable seasonal demands such as leisure centres, campsites and hotels, it allows for elements of the system to be shut down during off-peak periods. The other real advantage of adopting a packaged plant room approach to a DHW system is that the boiler or ASHP providing the preheat can be located in close association with the calorifier. The physical proximity helps negate problems of heat loss between the boiler, pipework and calorifier which can be detrimental if more widely separated in a system.

Discover more about Adveco water heating and how we can help size your DHW application.

 

Corrosion in Commercial Heating and Hot water Systems -3

Part 3 Preventing Corrosion – Glass Versus Stainless Steel

There are several methods for addressing different forms of corrosion that occur within commercial hot water systems.

Adding tin to brass, for example, creates Dezincification Resistant Brass (DZR). Fittings manufactured from this alloy will be marked in the UK with the letters CR (Corrosion Resistant) or DZR (dezincification resistant).

Commercial glass-lined steel water heaters and tanks are also attractive propositions as the glass is, given the right conditions, generally resistant to attack from most chemicals and corrosive materials. The glass is composed of several oxides and silicates blended and heated to the melting point. The first coat of glass is applied to develop a chemical bond with the steel of the tank and has limited corrosion resistance. After the ground coat, layers of chemically resistant glass are then added to create a smooth surface which is more resistant and easier to clean, making them popular in harder water areas.

However, not all glass-lining processes are equal with some being prone to developing microscopic cracks in the lining of the vessels. This means that small areas of the steel cylinder shell may get exposed to water, and there is an opportunity for corrosion to take hold.

Galvanic corrosion in water heaters and tanks is typically managed using cathodic anodes made of magnesium that offer a target for oxidisation in lieu of the steel shell, corroding or being ‘sacrificed’ first. Regular checks and replacement of anodes is critical in delivering ongoing protection from corrosion. Protective epoxy and plastic coatings can also be used to reduce corrosion by preventing conductivity from the water to the metal.

Corrosion in Commercial Heating and Hot Water Systems - Part 3The attack rate is determined by temperature, duration, and the concentration of reagents, for example, the presence of fluorides at any temperature will corrode a glass-lining.

In naturally soft water conditions, despite the use of sacrificial anodes, glass-lined vessels can rapidly succumb to critical corrosive damage. Due to a lack of dissolved metal ions, the purer soft water has low electrical conductivity, so the electrical flow from the anode to the cathode through the water is reduced. This adversely impacts the chemical reaction between sacrificial anode and cylinder shell, reducing the protection. In such cases, when the sacrificial anode is inspected its condition can be extremely good, but this is likely to be a strong indicator that the anode is failing in its role, meaning the water heater itself is being corroded.

The usual alternative to the sacrificial anode is the powered anode. Often made of titanium, the powered anode rather than giving up its own electrons and producing an electrolytic current produces a very low current in the water. This should provide a similar protective effect for a heater’s steel shell but without corroding the anode. However, in soft water areas, a powered anode may still not have a protective effect, as the conductivity required of the water by the anode is too poor.

For this reason, commercial hot water systems in Scotland, south-west and north-west of England and the west of Wales where water is particularly soft will typically need to employ a stainless-steel appliance. Better able to stand up to both water-side and combustion-side assaults, a stainless-steel heater is less susceptible to corrosion, due to the composition of the alloys, which create a protective oxide barrier on the waterside that naturally helps prevents corrosion, even when temperatures increase. Able to withstand higher temperature water (in excess of 80°C) than glass-lined appliances, stainless-steel lends itself to solar thermal and wider commercial applications.

Typically, stainless-steel will be used in indirect DHW heaters, where the internal heat transfer coil is connected to a boiler or a solar thermal collector loop; and in condensing water heaters where the push for higher efficiency condensing units has led to stainless steel being used to construct the heat exchangers. To achieve high efficiencies, flue gases must be cooled below the dew point to release the latent heat of condensation. With very low pH and high acidity, the resultant condensate would have a highly corrosive impact on the surfaces of the heat exchanger which regular steel or copper would struggle to withstand for any length of time.

Stainless steel is therefore preferable due to its versatility for creating intricate forms required by the heat exchanger and its high resistance to corrosion. This does mean stainless steel construction is typically more expensive, due to both higher material and manufacturing costs. Commercially, the investment is worthwhile, especially in soft water areas where, compared with replacement costs as a result of corrosion in glass-lined alternatives, stainless steel can prove far more cost-effective, with its quality reflected in the longer product warranties.

In the commercial world, domestic hot water (DHW) appliances are subjected to extremely hostile conditions, with high temperatures, thermal stress and flue gas condensate on the combustion side and oxygen, minerals and chemical attacks leading to potential corrosion on the waterside. Given this harsh daily treatment, regular servicing and maintenance are key if business-critical service is to be observed. Failure to descale, flush sediment, check anodes or test for corrosion will reduce the operational longevity of any appliance. In soft water areas, poor consideration of prevalent conditions and a lack of regular maintenance can reduce an appliance lifespan from years to a matter of months!

Correctly sizing, obtaining and then regularly servicing the right appliances and ancillaries for your application is critical if a hot water system is to operate safely, efficiently and cost-effectively.

Read Part 1 – Recognising the causes of corrosion

Read Part 2 – Testing for corrosion

Corrosion.

Corrosion in Commercial Heating and Hot water Systems – 1

Part 1 – Recognising the Causes of Corrosion

Most metals will deteriorate or corrode, sometimes to a more stable chemical state through oxidation or reduction. This occurs over time when metals are in direct contact with any water, rusted iron being the most familiar, but it can also affect copper, lead, aluminium, zinc, and numerous other common metals. This becomes a real issue in water heating and distribution systems where metal appliances and pipes are continuously being attacked to the point of physical failure.

Corrosion in Commercial Heating and Hot water Systems - Hard and soft water areas of the United Kingdom and IrelandCorrosion is a complex phenomenon, and no single dissolved substance is responsible for making water corrosive. There are several factors that can increase the likelihood of corrosion, especially the natural softness of water. When water passes through limestone and chalk in the ground, such as in the South East of the UK, it will pick up calcium and magnesium carbonates, when these minerals are greater than 280ppm the water is classed as hard. However, in Scotland, the North West and South West of England, and Western Wales, where water passes through hard igneous rock it lacks dissolved calcium and magnesium.  This makes the water naturally purer (less than 100 ppm). This soft water exhibits a low pH, low total dissolved solids (TDS) and negligible buffering capacity, all of which makes it more corrosive.

pH measures the hydrogen ion activity in a solution and is used to express the intensity of the acidity of a solution. Typically, the ideal pH for a hot water system is slightly above 7 on the pH scale. Water with a low pH (below 7) is acidic, which is a problem as acids are compounds that release hydrogen ions which oxidize metal, accelerating corrosion. In general, the lower the pH, the more aggressive the corrosion.

There can be a range of reasons for the formation of anodic and cathodic sites, required to produce corrosion. Different materials used in the manufacture of the appliance or pipework, localised stresses, impurities and variances in the production of the metal, its composition and ‘grain size’ can all lead to surface imperfections. If localised variances are relatively small the anodic and cathodic sites will move around on the surface of the metal leading to a more uniform corrosion which is typically seen as surface oxidation or fouling.

Should the anodic sites be more static, localised corrosion can occur. This form of corrosion – which includes pitting, leaching and galvanic corrosion – is a more serious problem which can more rapidly lead to the failure of an appliance or pipework.

Pitting, one of the most destructive types of corrosion, occurs when there are large differences in surface conditions, leading the anodic and cathodic sites to become stationary. The process is exacerbated by low-velocity conditions, leading to the creation of a pit on the surface of the metal, the water inside becomes isolated and, over time, more corrosive as it produces an excess of positively charged metal cations, which attract chloride anions. In addition, hydrolysis produces hydrogen (H+) ions. The subsequent increase in acidity becomes self-sustaining as the concentration within the pit promotes even higher corrosion rates.

Leaching is the selective corrosion of a single element from the alloy. The most common occurrence in a building’s hot water system is the removal of zinc from brass (a copper-zinc alloy), a process also known as dezincification. Though the copper and zinc dissolve out simultaneously, the copper will precipitate back from the solution. The resultant copper alloy will change from a yellow brass to red colour and exhibit poor mechanical property. Common in cheaper valves and fittings where there is likely to be other ‘filler’ metals in the copper alloy, water containing sulphur, carbon dioxide, and oxygen, low pH conditions, low velocity and high free chlorine radicals drive especially aggressive corrosion causing fittings or valves that move to fracture and leak.
The complexity of commercial hot water systems, especially if the project is a refurbishment, can lead to two dissimilar metals (such as copper and stainless steel) coming into contact with each other and water. Under these conditions the corrosion rate of the more active (anodic) metal increases and the corrosion rate of the nobler (cathodic) metal decreases. This is Galvanic corrosion.

The galvanic scale - Recognising corrosion in commercial heating and hot water systemsWhen differing metals are connected in a hot water system, the water in contact with both metals acts as an electrolyte conducting the current. The current flows through the water from the positively charged less noble material to the negatively charged more noble material. Where the current leaves the less noble metal, corrosion will occur. As the current is usually greater close to the contact point of the two metals, this is where corrosion will be a greater issue. The higher the metal is on the Galvanic series, the nobler the metal will be, whilst the greater the distance between the two differing metals in the series, the greater the electrical potential will be and the greater the corrosion rate for the less noble metal.

Another major cause of corrosion found in commercial hot water systems is a direct result of oversizing or the failure to correctly balance water flow. An unfortunately common occurrence, oversizing a system not only raises the capital expenditure and the running costs of a hot water system, but the oversizing of the pumps leads to high-velocity hot water to circulate through the system. If there are any suspended solids in the water, they will be driven against the metal leading to erosional corrosion which is typified by smoothly grooved or rounded holes which mirror the directional or turbulent flow of the water. This erosion is most notable at points where water changes direction or is obstructed, leading to turbulence which further increases velocity and therefore the damage. If the high-velocity flow is not addressed quickly it can result in considerable damage, especially to the circulating pipework.

Certain chemicals (such as chlorine, chloramine and dissolved oxygen) can also make water more corrosive. The presence of oxidizing agents such as dissolved oxygen can cause metals to lose electrons and lead to corrosion. The removal of sulphate, or addition of chloride, the Chloride-to-sulphate mass ratio (CSMR) will accelerate corrosion in the presence of materials that contain lead, leaching it into the water. Sulphates inhibit corrosion by forming passive protective film layers and reducing galvanic currents between dissimilar metals, chlorides prevent the formation of such passive layers and stimulate galvanic current. Should the source water contain natural levels of chloride and treatment be installed to remove sulphate, the expectation is this would push the CSMR up and as a result, accelerate corrosion. The base 60°C requirement for commercial hot water can worsen such cases as high temperatures accelerate almost all chemical reactions. As temperatures hit 70°C, which is not uncommon in commercial systems the rate of corrosion will increase.

Read Part 2 – Testing for corrosion

NHS sustainability

Caring for our Future

With the launch this January of the House of Common’s Climate Assembly UK which is tasked with bringing groups together to discuss achieving Net Zero targets, it was clear that much of the initial onus would fall on public sector organisations to become vocal in their support of the Government’s aims.

There is a tremendous challenge existing to drive the level of change needed to achieve Net Zero. The easy work has been done, such as shutting down coal-fired power stations, which has meant the Government’s Carbon Budget targets have so far been achieved. But the consensus has been that the next carbon budget will miss its target and subsequent others could fall further behind. And that was before Net Zero by 2050 was introduced. To successfully drive uptake of low carbon systems, which will on the most part be unfamiliar and deemed an unwanted, and for some an unwarranted cost, requires vocal support and better communications with, and education of, both the domestic and commercial sectors.

The Climate Assembly UK will have 110 representatives, randomly selected by ‘civic lottery’, giving voice to the UK public. They will hear balanced evidence on the choices the UK faces, discuss them, and make recommendations about what the UK should do to become Net Zero by 2050. Swaying these representatives who, by the very nature of the selection process, are unlikely to have more than a cursory understanding of the broad range of current fossil and low carbon technologies and practicalities of integrating them, means it must fall to key public bodies to take the first conclusive steps on the path to Net Zero.
In light of this, the NHS has made a wide-ranging statement on not only cutting carbon emissions to Net Zero but in particular reduce air pollution, of which Nitrogen Oxides (NOX) is, without doubt, one of the most concerning.

A by-product of the combustion of hydrocarbon fuels, NOX are a major contributing factor to poor air quality, the most toxicologically significant being a combination of nitric oxide (NO) and nitrogen dioxide (NO₂). It can cause lung irritation and respiratory infections as well as being linked to cancer, asthma, strokes, and heart disease. The Royal College of Physicians believe it directly leads to as many as 40,000 deaths each year. This has led to widespread recognition that more needs to be done to address NOX emissions and the care sector needs to be seen to be addressing emissions that are a by-product of its activities.

Sir Simon Stevens, head of the NHS, said: “With almost 700 people dying potentially avoidable deaths due to air pollution every week, we are facing a health emergency as well as a climate emergency.

“Patients and the public rightly want the NHS to deliver for them today, and to help safeguard the future health of our children and grandchildren.”
Whilst the press have focussed on the recommendations made to NHS staff to, such as encouraging less driving to work less and bringing in reusable cups and bottles, the real opportunities lie in two other proposals which a panel will now consider and respond to later this year.

The first would see a reduction, or cessation entirely, of up to 30 million outpatient appointments, which would have huge implications on reducing vehicle emissions, but could be a very difficult sell to the public.

The second, easier option, is to reduce emissions from buildings. The BBC reports Unison general secretary Dave Prentis, saying the implications for the NHS building stock were ‘huge’. “Everyone must now work together to understand how environment-harming heating and lighting systems can be replaced without redirecting funds from patient care.”

He is correct, as the levels of change Net Zero demands of any property could conceivably require heavy capital expenditure. Especially so with the NHS estate, where the demand would more likely require major refurbishment of existing, often ageing, properties that will not be fit for purpose in terms of low carbon solutions alone.

At Adveco, we have considerable experience working with and supplying hospitals throughout the UK with hot water and heating systems, offering a mix of gas, electric and low carbon technologies. Now, looking forward, we are rethinking how those systems can be used in a meaningful way to take us towards Net Zero. That means leveraging the advantages of low carbon technologies such as heat pumps and solar thermal, alongside the current generation of high-efficiency micro-CHP, gas and electric boilers and water heaters. This hybrid approach provides the versatility to use and enhance existing systems in building stock, gaining improvements without wholesale rebuilding which comes with a considerable price tag. The approach also acts as a ‘boarding ramp’ towards a whole new class of technologies including hydrogen and other ‘green’ gas alternatives.

Critically, the systems and applications that we are able to design, supply, commission and service are available today and can be shown to be cost-effective. We can accurately map operational costs and payback periods so that planners can budget for change with a high level of confidence. With long-term savings assured when correctly managed and maintained, there is no reason why improved heating and hot water systems should need to see funds being redirected from patient care. In fact, the savings over the next 30 years could easily be invested back into the NHS to the advantage of patients and staff.

Learn more about our work for the care sector

Adveco 2020 Product Overview Now Available

The 2020 Adveco Product Range brochure serves as a quick reference document covering a wide range of products and services provided by Adveco and A.O. Smith. The current range incorporates commercial hot water and heating equipment including: condensing gas water heaters; storage tanks, oil & electric water heaters; solar thermal; boiler cascade systems; stainless steel cylinders, thermal storage tanks, carbon steel buffers, combined heat & power (CHP); Air Source Heat Pumps (ASHP). These technologies are the building blocks for Adveco’s bespoke packaged plant rooms and system offerings. All supported by our applications and field engineers who provide expert commission services, warranty maintenance and training.

If you are seeking support in the design, supply, commissioning or servicing of business-critical hot water, heating and power then this brochure is a useful tool to have to hand.

You can download the brochure now.