Solar collector panels.

Solar Thermal – Proven Route to Sustainability

A.O. Smith Solar Thermal SGS system

The A.O. Smith Solar Thermal SGS system

Solar thermal represents a vital component for addressing sustainability within commercial organisations. Obviously, solar thermal systems are most productive in the summer months, when there is most sunlight, so this does result in the additional need for non-renewable energy sources during the winter months. Despite this, sustainability is more than achievable, and Adveco will design applications and package the appropriate technology. The A.O. Smith SGS solar water heater with IT storage vessel is a perfect example of a sustainable application. The intelligent solar control of the system ensures maximum efficiency. Even with little solar input, the required hot water temperature is guaranteed by the gas burner operating as a back-up system.

SGS System in situ on North Cumbria Police Headquarters’ award-winning ‘green roof’.

SGS System in situ on North Cumbria Police Headquarters’ award-winning ‘green roof’.

An example of this application in practice is the North Cumbria Police Headquarters’ award-winning ‘green roof’. The building incorporates an A.O. Smith SGS 60-ITE 750 solar system. The solar heat input collected by the 2×5 solar collectors (on-roof-frame construction) is transferred to the available hot water supplies via the ITE 750 which is controlled together with the collectors by the SGS 60. With the use of a single system controller the SGS 60 only fires its high efficiency condensing gas burner when hot water demand outstrips the available stored and solar heat input.

When Stockport Metropolitan Borough Council’s Ponsonby Building was refurbished into a stylish working environment for more than 450 staff, 12 solar collectors were installed on the outside wall feeding an A.O. Smith ITS 1000 to meet the hot water demand. The ITS, an indirect tank, is fitted with two coils. In solar configuration, the upper coil is connected to the primary circuit (boiler) whilst the lower coil is connected to the solar circuit. The top coil after-heats the water if the solar contribution is insufficient. The lower coil transfers the solar contribution which is collected by the solar collectors.

If a solar thermal application is designed to leverage the Government’s non-domestic Renewable Heat Incentive (RHI), this adds a new revenue stream that helps to increase return on investment and reduce the payback period.

Designed to provide financial incentives to increase the uptake of renewable heat by businesses, the public sector and non-profit organisations, the Government has spent £550m to date on non-domestic RHI to reduce carbon emissions. RHI is currently applicable to solar thermal for commercial uses including large and small businesses, plus schools and hospitals. Administrated by Ofgem on behalf of the Department of Energy and Climate Change (DECC), tier one of the RHI incentivises non-domestic energy producers for either the life of the installation or 20 years as a maximum. If conditions are met, with equipment, including a generation meter, being installed by a microgeneration certification scheme (MCS) accredited installer, eligible businesses in England, Scotland and Wales will continue to be paid for installations completed and commissioned before 2021. After 31 March 2021 new installations may not receive any form of subsidy.

Successful systems will them receive quarterly payments per kilowatt hour (kWth) of energy use, however, if your system is metered as a multiple system, which includes both solar thermal and a gas boiler, then payment is made purely for the heat generated by the solar thermal aspect of the application.

Changes to, or a replacement for, the scheme after March next year are currently to be finalised, but whilst the expectation is that solar thermal will play a role in the long-term decarbonisation of heating in the UK, the technology is not deemed a stand-alone solution for phasing out fossil fuels within buildings. As such, the current Government’s stance under the incoming Green Heat Grant is that the technology will not be supported under the new policy mechanism.

The current 2020 tier 1 (non-domestic) tariff for new solar thermal collectors less than 200kWth in size is 10.98(p/kWh)*.

No single technology currently provides the ‘magic bullet’ of sustainability, but for organisations with long-term vision and a willingness to invest in sustainability, solar thermal when correctly sized, commissioned and protected from overheat, is a proven and practical technology for securing on-premise DHW. When delivered in conjunction with other technologies, including high-efficiency gas and electric heaters, micro-CHP and ASHP, you can future-proof a hot water system whilst making substantial savings in operational costs and dramatically reducing emissions all year round.

*For more information on non-domestic RHI and the full conditions of eligibility, refer to the energy regulator Ofgem.

Read more about Solar Thermal from Adveco

Adveco commissioning

Adveco Covid 19 update – Engineering Site Visits

The provision of heating and especially hot water within hospitals and residential care facilities, supermarkets and those supporting key workers, such as schools, is being actively prioritised for support by Adveco. An important aspect of that work is the provision of site-based engineering services for emergency call outs, ensuring priority customers have a reliable supply of heating and, in particular, hot water.

Regarded as essential work, we are still providing this service in these times of social distancing and stay at home rules. Adveco is taking all necessary measures to protect its staff and help prevent further spread of the Coronavirus. As a result, we have made some alterations to our engineers’ working practices and we ask for your patience and help to keep them safe while doing their jobs. This will help to ensure we can continue to offer this critical engineering support throughout the duration of this pandemic.

While on site, we will be instigating the following changes to protocols to ensure the safety of our engineers:

  • No signing in – site contact to sign the engineer in.
  • No classroom-style inductions – inductions, if necessary, take place outside as toolbox talks, ensuring distances of over two metres from others.
  • No entry into crowded areas / areas that are heavily trafficked / areas where people loiter – the engineer is to phone and the site contact should come outside to meet him and take him around the outside of the building to the plant room. Plant room to be accessed from the nearest external door (not by walking through an occupied building, unless at the engineer’s discretion, he has our full support if he deems the risk too high). Please advise prior to the visit if you feel plant room access may be problematic.
  • No one else to be working in the vicinity / in the plant room while our engineer is there.
  • No signing out – site contact to sign the engineer out.
  • The site must provide facilities for hand-washing.

We will be requesting that agreement to the above protocols be agreed in writing prior to an engineering visit. If these allowances cannot be accommodated, we will deem the work non-essential and attendance will be rescheduled following the Government mandated ‘stay at home’ period.  Our engineer will carry out a risk assessment on arrival and if you cannot provide the stated conditions then he has been instructed to abort the job, this will incur a standard aborted visit fee.

We are sorry to have to impose conditions on our visit, but we are committed to the health of our engineers and the ability to continue to support our many customers providing key services to the nation.

We appreciate your support in these extraordinary circumstances.

Adveco Covid-19 update.

Adveco Covid-19 update

During these unprecedented times, and in response to the latest Government advice to all businesses in the UK, Adveco is taking all necessary measures to protect its staff and help prevent further spread of the Coronavirus.

Our services have always been regarded as business-critical to our customers, and with so many providing front-line support in the UK in the fight against this pandemic, it has never been truer.

I want to assure you that Adveco and our sister company A.O. Smith Water Heaters remain open for business. We continue to operate from our Farnborough HQ but with a reduced staff for the duration of April. This is of paramount importance to us, to maintain our supply lines and ensure deliveries are made so your projects are not delayed.

We are well stocked, and our field engineering teams are on hand to respond to ongoing emergency call outs.

As the situation continues to develop, it has become clear that we, like so many businesses, must prioritise our services in response to the critical needs of customers across the health sector. The provision of heating and especially hot water within hospitals and residential care facilities that provide for those most at risk must take precedence at this time. We will be endeavouring to ensure all product and engineering support is made available in the fastest time to customers within the health sector. Supermarkets and those supporting key workers, such as schools, will also be prioritised for support by Adveco.

We are happy to discuss the needs of your project or servicing requirements but hope you will appreciate that if you are not providing key services at this time that our response may be delayed.

We will operate a small retained team for the coming month to support your needs, but you may experience a delay in response when contacting the office. We are responding to all calls and messages but apologise if you are unable to get an instant reply. We appreciate your patience.

To reiterate, Adveco remains open and ready to meet your commercial hot water and heating needs. We appreciate your support and understanding.

David O’Sullivan

Managing Director

Adveco / A.O. Smith Water Heaters UK

 

Reduce Carbon with Air Source Heat Pumps (ASHP).

Reducing Carbon with Air Source Heat Pumps

It is estimated that 40% of CO₂ emissions can come from commercial heating alone and finding new and innovative ways to heat premises is at the top of the list for many businesses.

Reducing Carbon with Air Source Heat Pumps (ASHP)Commercial sites – education, healthcare, retail, logistics, offices, hospitality and leisure – seeking to reduce both their carbon footprint and energy bills have with air source heat pumps (ASHP) an opportunity to gain a long-term cost-effective means to heat water and space.

Whilst the cost of installing an ASHP will vary depending on the size and complexity of the commercial premises, there is no doubt that despite the initial outlay on a heat pump system there are significant savings that a business can make. Particularly if it is currently using electricity, oil, solid fuel or liquid gas to heat premises. When correctly installed by a qualified supplier, a commercial heat pump with minimal, regular maintenance should typically last 10 to 25 years. And, commercial businesses can still benefit from the Renewable Heat Incentive (RHI) initiative from the Department of Energy and Climate Change that pays per kilowatt-hour produced from sites accepted onto the scheme prior to March 2021.

Initial costs can be seen as prohibitive, but once the break-even point has been reached there is potential for significant savings and a solid return on investment. This, of course, assumes that a commercial property is suitable for an ASHP installation which will require space adjacent to an exterior wall or a flat roof space to situate the unit.

As we have seen, ASHPs offer a great many benefits, but there are also limitations, but it is important to recognise that with all low carbon technologies there are technical limitations that will not allow them to work effectively as a standalone heat source without substantial infrastructure changes.

Market insight has shown a trend for hybrid heat pump and solar thermal systems, which is a direct response to the limitations of solar alone, which is applicable to daylight hours only and can be limited during winter by the shorter days. Solar Thermal therefore only ever makes up a proportion of the load. Solar Thermal can also be a complex install so is not applicable for refurbishments where time is at a premium or a site is not secure as it can be at risk from damaged. M-CHP, cogenerating onsite heat and power, will be used as a baseload product to maximise its running hours and is certainly an option when it comes to addressing peak hour demands but may be cost-prohibitive.

A heat pump could well be standalone in a new build, but we would assume that most commercial buildings do not have sufficient electrical supply, and upgrading the existing electrical infrastructure can immediately become cost-prohibitive for a project.

Using a modelled ‘benchmark’ existing hotel site, with an average of 224 daily guests, each using an average of 50 litres of hot water per day provided by a traditional boiler-fired heating system we can assess the potential of ASHP when replacing the traditional boiler system.  A commercial ASHP offering optimum operation (91,611 kWh electrical input for 190,773 kWh thermal output to meet annual DHW demand of 4,088,000 litres) will be limited to 55 degrees, the maximum stored water temperature is 50 degrees and therefore the heat pump output restricted to approximately 191 MWh. The annual cost savings can be modelled at £1,127.27 giving a system payback of 23.1 years if we estimate equipment costs to be £16,000, with £10,000 of installation costs. Carbon savings are positive, compared to smaller heat pumps which model with negligible gains, in this case saving 28,237 kg CO₂/annum which is truly advantageous.

What this example demonstrates is that there is a core business decision to be made when balancing carbon savings against project cost payback for standalone ASHP systems. Existing commercial buildings can achieve significant carbon savings through the utilisation of the correct technology.

Reducing carbon emissions is ethically the correct thing to do, and ASHP, Solar Thermal and m-CHP will all achieve savings to varying levels, but realistically the cost of the technology must also be considered when making any decisions regarding significant upgrades to the building’s energy systems, which means, unless there is major governmental legislative intervention or funding, there will almost certainly be a compromise of cost, carbon saving and payback.

Learn more about Adveco FPi Air Source Heat Pumps

Packaged plant room

Offsite Construction For Heating – An Educated Decision

Understand how schools can use packaged plant rooms from Adveco to rapidly deploy hot water, heating and cogeneration.

Provisioning a modern, efficient, cost-effective and sustainable business-critical hot water and heating system is not necessarily straight forward for some sites. They may be limited in terms of existing plant room space, or in the case of much older buildings, have no dedicated plant room space at all. Other sites may face limitations in terms of when work can actually be carried out on site. If a works window is especially narrow it can preclude larger scale project work.

The proper coordination of equipment, controls and timely project delivery are the most difficult, and therefore costly, aspects of creating a modern heating and hot water application for schools. When a project faces the kinds of limitations outlined, one answer is to make use of an external plant room to relocate essential building services, increasing the availability of valuable internal areas.

This was the route a Berkshire school recently opted for to address these challenges by sourcing an Adveco bespoke, pre-built packaged plant room, leveraging micro-cogeneration and condensing gas boilers to meet the school’s specific central heating and domestic hot water (DHW) needs.

As a packaged plant room is prefabricated off-site, it arrives with all appliances, controls and ancillaries pre-fitted and connected, ready to be sited immediately upon delivery. This dramatically accelerates overall project delivery timescales; minimises on-site labour demands and considerably reduces costs.

Sized, designed, and manufactured to order by Adveco, the Berkshire school project featured a single, large 7m x 4m reinforced GRP weatherproof enclosure with a steel base and checkerplate floor suitable for placement on top of the school building’s flat roof space.

TOTEM T10 micro-CHP (Combined Heat and Power)Incorporating a 10 kWe / 22 kWTh TOTEM T10 micro-CHP and, a full cascade of condensing boilers, 2000 litre carbon steel buffer vessel, expansion tank, pumps, controls, meters and pipework. All delivered pre-built and ready to be installed within days. The plant room just requires flues, external pipework and final electrical connections to be completed.

To achieve the best results, the decision-making relating to heating and DHW systems needs to be finalised early on to allow for the increased lead-in times. Adveco’s design engineers guided the school through this process to ensure a highly resilient system was fully defined for before construction began.

Packaged plant roomAs well as maximising space, packaged plant rooms provide a proven method to secure new, highly efficient and cost-effective to operate hot water, heating and low carbon systems. Schools can opt for a choice of gas, electric or renewables, such as Air Source Heat Pumps, or these can be combined into a single packaged hybrid system. While delivering rapid return on investment and lower ongoing operating costs, such hybrid systems can also help provide a timely answer to meeting new sustainability targets across school estates.

Discover more about Adveco packaged plant rooms.

Micro-CHP and The Urban Balancing Act.

Micro-CHP and The Urban Balancing Act

Adveco expert Bill Sinclair, Technical Director.Adveco’s Technical Director, Bill Sinclair, discusses balancing concerns over the cost to health from NOx emissions with the advantages of using micro-CHP in urban commercial building projects.

A by-product of the combustion of hydrocarbon fuels, Nitrogen Oxides (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 believes it directly leads to as many as 40,000 deaths each year with an estimated cost of £20 billion to the country in healthcare and lost working days. This has led to widespread recognition that more needs to be done to address NOx emissions with attention more than ever-shifting to encompass the production of emissions from the built environment.

With a greater emphasis on renewables to make our cities more self-sufficient and resilient in terms of meeting energy needs, low carbon electricity’s share of generation has currently risen to a record 50.1% across the UK with (33.4% of which is generated by renewables). But, as old power plants go offline and are replaced by unpredictable supplies like solar and wind, combined heat and power (CHP) becomes increasingly advantageous. Able to reduce a building’s reliance on the grid, yet when demand is high such as when it is cold and dark, provide a more reliable power source, CHP also has the added benefit of providing high-grade heat at lower cost in conditions where a heat pump coefficient of performance falls and the energy cost increases beyond that of gas.

Although all CHP with a catalytic converter is cleaner than the grid, localised NOx emissions from ‘dirty’ cogeneration should be a concern. Where CHP is used to offset condensing boiler run hours, if the CHP is dirtier than the condensing boiler then the local emissions are worsened. Despite air pollution and NOx mainly arising from road traffic – half of the current NO­x pollution in London is attributed to vehicles – emissions from decentralised energy production are now being seen as a contributing factor. It is therefore of great importance that the NOx emissions from new CHP units within built-up areas are lower than condensing boilers if they are to have a positive effect.

Setting a new threshold for emissions

Micro-CHP (Combined Heat and Power) in urban commercial building projects.The 2018 EcoDesign directive sets a NOx emission limit for CHP units at 240mg/kWh. This threshold, despite being approximately equal to emissions that would result from producing heat from a boiler and consuming electricity from conventional power plants, is too lenient. Air quality has been a critical driver in the revisions within the London Plan which now treats CHP with a lot less enthusiasm – although still accepting that there remains a strategic case for CHP systems as long as the NOx emissions are equivalent or lower than those of ultra-low NOx gas boilers.

The cogeneration industry has not been sitting on its laurels, and a new generation of ‘clean’ CHP brings all the advantages of onsite, on-demand cogeneration, and exceeds the London Plan’s expectations of ‘very low levels’ of NOx, meeting Euro 6 standards for emissions. More compact and much cleaner, micro-CHP units (in accordance with EU standards at 50kW or less rated electrical power) are available with far lower emission rates. This is the case for the TOTEM m-CHP, for example, which is independently certified at just 10mg/kWh.

If we compare a CHP meeting the 2018 EcoDesign limit of 240mg/kWh to that of a TOTEM m-CHP, we can demonstrate the real difference in the latest generation of CHP. Using a unit of 20kW electrical output, a gas input of 70kW, in a situation with an average annual run time of 6,500 hours for a standard application such as a hotel or apartment block, the yearly NOX emission from a ’dirty’ CHP will be 109.2kg/year, compared to 4.55kg/year for Adveco’s TOTEM. And remember, this option is also improving local air quality because the m-CHP is used to offset the run hours of a condensing boiler which at emissions over 30 mg/kWh is dirty compared to the CHP.

Hybrid futures

There will always be projects where in certain circumstances m-CHP will have a place and other renewables are closed out due to limitations of either the site or the technology. By the same token, we would never advocate m-CHP for every building. As is so often the case in the commercial world, each project will have its specific requirements, requiring a more bespoke approach to the provision of hot water, heating and power generation.

Increasingly we hear from consultants who are struggling to pass any kind of gas or gas CHP based heating system because of the issues around NOx emissions, despite the advantage of the high-grade heat necessary to meet the needs of commercial projects. Simply opting for heat pumps, providing a lower grade of heat, isn’t a practical alternative. One answer then is to use a combination of two or three technologies to provide a high heat, low cost, low NOx system.

This is particularly relevant to large buildings where a heat pump alone is simply not suitable. These projects need an additional, high-grade source of heat. Now, that essentially takes you to gas, but if the building is big enough, after the heat pump, but before the gas, can sit m-CHP to provide low NOx and very low running costs.

We can also make a case for using Combined Heat and Power in existing buildings which already have gas boilers and do not have the electrical supply needed to utilise a heat pump. Again, it does not make sense to fit just a heat pump. But we do not want to use CHP to offset low-temperature heat pumps, it has to sit after a heat pump, offsetting the gas heater. Such an approach will still offer some carbon savings, definitely cost savings and, if that CHP is a low NOx appliance when compared to the boiler, then we also have NOx saving. At worst such a system is going to be carbon neutral, but cost and NOx effective.

The move towards all-electric in smaller buildings also reopens the door for solar thermal with better payback case and better carbon savings. Used in conjunction with low-temperature ASHPs in an arrangement to ensure that it offsets the high-grade source, it offers an alternate hybrid approach that does not require CHP. But we believe gas-fired m-CHP will continue to play a necessary role as part of many hybrid systems, achieving effective water temperatures for commercial applications whilst balancing running costs and savings.

As with any project, design what is best for the building. We would never advocate ignoring the risk of increasing air pollution locally with ‘dirty’ CHP systems, so if Combined Heat and Power is the best fit for your project’s needs then it is vital to choose the lowest NOx emitting equipment available. Right now, the Mayor of London is supporting the city’s Cleaner Heat Cashback scheme for SMEs, proposing scrapping of old gas boilers and replacing them with a variety of options including new efficient gas boilers. If we can demonstrate that m-CHP, either standalone or in a hybrid system, can offset condensing boiler run hours and make emissions cleaner then there is surely a place for the technology, even in the centre of our busiest cities.

Discover more about TOTEM m-CHP

Download the TOTEM m-CHP brochure

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 commercial 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