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Navigating Regulations & Application Design for Commercial Hot Water Systems

There are huge expectations placed on building services engineers and sustainability consultants to be experts on the regulations for the built environment and the ever-developing technologies employed to meet them. The most important systems and features of the building, such as its fabric, power, heating and cooling systems are well understood and can be confidently dealt with when specifying and delivering a project. Designs including non-traditional and secondary systems are where engineers can be at a disadvantage due to the vast amount of changing information that they need to know. These systems can include domestic hot water (DHW), renewables plus the control of them, and gas appliance flueing.

These secondary systems on commercial projects are therefore a perfect opportunity to lean on more specialist application design services so that consultants can place their focus on the mainline elements of a building project. At Adveco, we have supplied specialist design support for the past 50 years, ensuring typically bespoke applications meet regulatory demands and best practice to sensibly manage capital expenditure while ensuring system longevity for better operational life.

In recent years we have come to recognise three prime ways that specialist application design becomes truly advantageous to a commercial building project. The first is in supporting mechanical and public health engineers deliver comprehensive and highly efficient DHW systems. The second is aiding sustainability consultants in the integration of renewables. The third is in helping engineers and D&B contractors to address the complex regulations surrounding the installation of flues for gas-based systems.

With DHW applications the primary issues are always going to relate to correct sizing based on the demands generated by a building’s occupants and choice of system. These can be based on application, energy source, suitability, and integration with carbon saving technologies,

Oversizing DHW systems inherently come from a lack of understanding of hot water demands within the building, diversity, and length of the peak period. Oversizing is exacerbated by the false belief that the building uses more hot water than it really does, and an attitude of ‘better too much than not enough’. Sizing programmes, often employed for a quick sizing early in the design then never reviewed, do not deal well with the many variables and decisions on diversity leading them to oversize to prevent hot water problems. Traditionally the problems with oversizing, such as increased standing losses, increased outlay costs, increased pipe sizes, and increased space use may have been minor in terms of the cost of the whole building, but it now has another important knock-on effect. If the hot water consumption is overinflated, it falsely increases the expectation of the building’s carbon emissions. This then requires greater employment of renewables to reduce emissions which do not actually occur. This can come at great cost and complication and provide little benefit to the building. Access to realistic sizing tools and having the experience to interpret results requires both expertise and time, which specialist application design can bring to a project.

The integration of renewables, such as air source heat pumps (ASHP), heat recovery and solar thermal, will further increase the complexity of a system. Renewable technologies are going to be selected early in the design process to secure the Part L approval, once modelled successfully it is not wise to start changing things too severely. Small changes, such as revising the manufacturer of an appliance is going to make little difference within Part L, but if you have to add, remove and replace a technology, then you are going to be back at the beginning, and will almost certainly need to resubmit your Part L calculations. These early selection decisions increasingly reside with the sustainability consultant before the design engineer is involved, which means they need a broad knowledge of building services systems beyond the renewables themselves. Working together with specialist application design means they can better advise on selecting the right type of renewable to ensure it will integrate with the rest of the system and be controlled to work with traditional technologies. It is very important that renewable heat sources, particularly those that provide low-grade heat, are not held off by traditional boiler systems providing high-grade heat to high-temperature systems. This is not purely a controls issue but one that requires an in-depth understanding of the complete system arrangement to set it up effectively.

Finally, a regulatory issue that continues to impact consultants, engineers and D&B contractors has been the change to flue and gas standards.

IGEM/UP10 Edition 4 is an Institute of Gas Engineers and Managers utilisation procedure which attempts to address two major points of confusion: safe horizontal termination and the definition of a group of appliances. Adveco applies this document in all relevant plant room design since limits on horizontal termination through a wall terminal at low level is clearly important from a safety perspective. Many designers and installers remain unsure how to apply it correctly which can have a major impact on commissioning if the termination is not found to meet the current regulations.

Under UP/10, groups of terminals are defined by a mathematical formula which sets a corresponding dimension. Terminals that are within the calculated dimension of each other are k,89a group regardless of type or location. A group of terminals with an input over 70kW (net) that terminate horizontally must now be tested against a risk assessment provided within UP/10; this could therefore include terminals from appliances with outputs below 70 kW that previously would not have been considered if their terminals conformed to BS5440. The IGEM procedure will potentially allow up to 333kW (net) to be exhausted at low level if it is deemed risk free (such as a windowless wall looking over open fields) but will not allow 70kW to be exhausted at low level if deemed unsafe (such as an internal corner, or adjacent to openable windows, walkways, or a playground). Despite holding British Standard (BS) equivalency and being published for more than five years, UP/10 remains underused in the early design phase where it should be used to determine when flues must terminate at high level so that they can be included in the installation budget.

Faced with an ever-widening range of technology and regulations, access to a specialist design for these secondary systems is an extremely useful asset, one that can be both an independent sounding board and an extension of the in-house design function. That saves valuable time, delivers a better project specification and helps avoid problems that can halt final commissioning of a system, delaying or even preventing a building’s final handover to the new resident.

Enquire about sizing your project 

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

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 CO2emissions.

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.

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

Government Outlines Ten Step Plan In Drive Towards Net Zero

Prime Minister Boris Johnson has announced a £4bn package to: “Create, support and protect hundreds of thousands of green jobs, whilst making strides towards net zero by 2050.”
“Our green industrial revolution will be powered by the wind turbines, propelled by the electric vehicles and advanced by the latest technologies, so we can look ahead to a more prosperous, greener future.”
The plan is wide-ranging, with a clear focus on creating jobs and addressing climate change at the same time, but many have challenged the allocation of funds needed to deliver on the challenge.

The Prime Minister’s plan outlines ten key deliverables:
1. Produce enough offshore wind to power every home in the UK, quadrupling how much it produces to 40 gigawatts by 2030
2. Create five gigawatts of ‘low carbon’ hydrogen production capacity by 2030 – for industry, transport, power and homes – with the first town heated by hydrogen by 2030
3. Making homes, schools and hospitals greener, warmer and more energy efficient, including an aggressive target to install 600,000 heat pumps every year by 2028.
4. Accelerate the transition to electric vehicles by phasing out sales of new petrol and diesel cars and vans by the end of the decade
5. Advancing the provisioning of nuclear power as a clean energy source, with new plant likely to be located at Sizewell and a new generation of small nuclear reactors
6. Invest in zero-emission public transport for the future
7. Support projects researching zero-emission fuels for planes and ships
8. Develop carbon capture technology with a target of removing 10 million tonnes of carbon dioxide by 2030
9. Plant 30,000 hectares of trees a year
10. Create a global centre of green innovation and finance based in the City of London

Business Secretary Alok Sharma has stated that the announced £4bn investment is part of a wider £12bn package of public investment, but to put that sum into perspective, Germany has already committed to a €7bn investment in hydrogen alone to deliver a filling station network and create a hydrogen-powered train.

Concerted efforts to further decarbonise the grid through offshore wind, nuclear power and a further a subsidy of up to £500m to develop hydrogen production, partly by excess energy from offshore wind, will continue to impact on the way new and replacement commercial heating and hot water systems will be designed. But there remains little indication of how these investments in the green economy will directly support commercial organisations coming under pressure to address ageing, inefficient systems. The Government failed to gauge the scale of demand from domestic sites with the Green Homes Grant, and this plan has extended that support for a further year to attempt to address the over-subscription already seen, and the same can be said for businesses that are facing a short timeframe to secure non-domestic RHI support, without a clear replacement being announced. The initial propositions for replacement commercial Green Grants, being excised.

The drive to see the installation of 600,000 heat pumps a year by 2028 is again a domestic focus, although hospitals and schools have been quoted in the same breath, and no doubt additional public sector funding is going to be extended to drive this adoption. But it is worth remembering that the demands and complexity of a commercial system based around a heat pump is decidedly more complex than a domestic installation. Even now, the domestic market is struggling to identify where the large number of competent, approved installers for these hundreds of thousands of heat pumps is coming from, and that scenario will be more deeply felt in the commercial space. The lack of provisioning for large scale retraining of installers is concerning, and again a failure to show support for commercial organisations that are increasingly being mandated to demonstrate clear and real investment in sustainable and low carbon technology seems to be a critical oversight. Especially given the percentage of emissions building stock contributes each year.

Labour MP Alun Whitehead, shadow minister for Business, Energy and Industrial Strategy, has stated that a mixed approach encompassing different technology types such as electric and gas solutions was the way to ensure heat decarbonisation. “We believe in speedy progress on heat decarbonisation, but we need to see a horses for courses approach. This would include heat pumps – or hybrid heat pumps where appropriate – particularly in new build and off-grid properties; district heating islands in more urban areas; and a substantial expansion of green gas (bio-methane and hydrogen) in the system.“

The Labour Party expects gas heat, specifically from boilers modified for greener fuels, to be an essential part of the decarbonisation of UK buildings. Labour’s Green Economic Recovery strategy hints at the importance of hydrogen, and in sourcing greener hydrogen produced via electrolysis, for transforming how buildings get their heat. It also highlights the need to retrain workers and create new roles around greener energy and infrastructure, as well as supporting businesses to become more sustainable.

There remains a year until the COP26 UN summit, to be hosted in Glasgow, anticipated by many to be the most critical since the Paris Agreement in 2015. That gives twelve months to further define objectives and provide a clear path with meaningful inducement for the commercial sector if the increasingly aggressive timetable is to be met. The previous carbon budgets set by the government have been achieved, but the ‘easy wins’ are now behind us; future carbon budgets are no longer on track to be achieved and it will only get more difficult. This ten-point plan, should be seen as encouraging, establishing a more defined set of targets for the nation, but greater clarity is required and much still needs to be done in terms of ensuring their practical delivery.

Talk to Adveco today about how you can leverage renewables including air source heat pumps, solar thermal and heat recovery to drive sustainability within your commercial hot water and heating systems.

Making ASHP Work For Commercial Applications – Part 2

The Hybrid Approach

In part one, we considered the challenges and limitations of an Air Source Heat Pump (ASHP) only system, with particular focus on the problems commercial organisations faced when retrofitting existing properties with new heating and hot water applications. In this concluding part, we look at the advantages of adopting a hybrid system approach based on ASHP technology…

A hybrid approach where an ASHP is deployed in a packaged combination with a gas boiler and control system presents an attractive alternative, retaining the element of gas boiler technology that customers are comfortable with. Plus, it also offers better compatibility with existing heating distribution systems and thermal demands of higher heat loss buildings meaning less adaptation is required. There are also technical advantages, such as the ability to optimise heat pump efficiency and switching to the gas boiler at times of network peak.

The facility of two heat sources to meet the demands for space heating and/or hot water is especially relevant for the commercial sector where bespoke system design is often required to meet the particular needs of a project, such as applications with a high heat loss. In this case, the gas boiler can be operated to meet peak demands on the coldest days, allowing the heat pump to be reduced in size compared to the capacity of a pure electric heat pump system.

Installing a heat pump alongside an existing gas boiler, together with a control system also makes sense in retrofit installations, especially, in applications where a relatively new boiler has been installed, which should be highly efficient, and which can be retained for peak heating loads. The key challenge technically is to ensure that the control system for the ASHP and existing boiler operate together efficiently.

In such cases, given that the ASHP does not replace an existing heating system, the driver for installing the system is largely to reduce running costs and make quick gains towards improving environmental performance.

Hybrid systems based around an ASHP are likely to require some system refurbishment in many retrofit installations in order to ensure that a substantial proportion of the annual demand is met by the heat pump (though this is likely to be lower than a pure electric system). Even so, when including the cost of a gas boiler replacement, the cost of refurbishing heating systems for the installation of a hybrid system should be lower than in the case of a single heat pump system. This is due to the reduced heat pump capacity requirement since the boiler can provide higher flow temperatures to meet peak heat demands. When comparing the cost of a heating system refurbishment opting to install a hybrid system versus a ‘pure’ ASHP system a reduction in comparative costs of as much as 50% could be achieved (Source: Frontier Economics).

Once installed, levels of carbon savings are generally slightly higher when allowing for hybrid solutions – suggesting that up until 2030 hybrid solutions could be consistent with meeting carbon targets. Although the average cost-effectiveness of carbon abatement is somewhat lower than in the scenarios which exclude hybrids. These savings are estimated based on comparison with a standalone ASHP, assuming that a hybrid system will use a smaller heat pump with a capacity reduced by as much as one third. For a hybrid ASHP system, expectations will be for the heat pump to meet as much as 75% of the annual heat load, the remainder being met by a gas boiler. This delivers similar operating costs and comparable CO and CO₂ savings at current grid carbon intensity (the reduced heat pump coverage of the overall thermal demand can be compensated by the ability to run the heat pump at closer to optimum efficiency).

Whilst the long-term use of hybrid systems may be perceived as not fully consistent with meeting carbon targets and they can equally be limited by space requirements and noise issues that also affect standalone ASHP installation, there remains a strong argument for their use across the commercial sector.

In the long term, hybrid systems should fall behind pure electric systems in terms of carbon benefits as the grid decarbonises and may become less cost-effective if volumes of gas supplied for the heating drop. But looking out to 2050, innovations in the provision of hydrogen and green gas, using extant infrastructure which currently supports 85% of UK heating, means hybrid systems may prove to be a defining low carbon option. One that provides the means to support the very particular, practical needs of the commercial market with versatile, cost-effective systems, all without sacrificing the drive to lower emissions as part of the process of achieving net-zero.

Read about Adveco’s compact commercial FPi ASHP range and prefabricated packaged systems for a hybrid approach.

Bromsgrove Leisure Centre.

Sustainable Energy For The Leisure Industry – Part 2

In part 1 we discussed the importance of understanding how hot water, heating and power demands can be cost-effectively brought into balance, and why hybrid systems are key to achieving long-term sustainability…

As well as being able to be cost-effectively controlled, a hybrid system can also be optimised for CO₂ emissions by selecting the optimal (ecological) heat generator whenever possible via an energy management system incorporating smart metering. Should the building envelope subsequently be renovated, the required heating load will decrease further, and the existing gas boiler can take on less of the annual heating work and eventually could even be retired.

Depending on a building’s demand, we can also make a strong case for combined heat and power (CHP) where the CHP generates onsite electricity from a gas-powered engine, efficiently recovering heat from the process. Such an approach will still offer some carbon savings, definitely cost savings and, if that CHP is a low nitrogen oxides (NOₓ) micro appliance (m-CHP) when compared to the boiler, then we also have NOₓ saving. At worst, such a system is going to be carbon neutral but crucially low NOₓ which is increasingly a requirement for consultants and specifiers to pass building planning.

m-CHP also benefits from inclusion in the new SEG legislation so excess generated electricity can be sold to offset the CAPEX. The addition of m-CHP does require a certain level of oversight, so it is important to factor in the costs of regularly monitoring, managing and maintaining the system to ensure long term guaranteed efficiencies and relatively rapid ROI. As a result, compact micro-CHP systems have proven to be an extremely popular option across the leisure industry.

Adveco recently supplied Travelodge’s flagship 395-room London City hotel with a system that features an Adveco TOTEM T25 m-CHP unit. With continual background electrical power use and large domestic hot water (DHW) demand, Travelodge committed to a system based on micro-combined heat and power (m-CHP) which, when compared to conventional hot water solutions, attains substantial improvements in energy efficiency and reduced emissions.

Beautifully designed and fitted boiler room with mCHP, calorifiers etc.

The m-CHP pre-heats the system water via an MSS buffer vessel, which feeds six stainless steel calorifiers supported by a 572 kW A.O. Smith Upsilon boiler cascade. These plant components, all supplied by Adveco were installed into a rooftop plant room and commissioned by Adveco’s in-house team of engineers. m-CHP proved the most practical and cost-effective method for Travelodge to satisfy Part L of the Building Regulations, aiding its demand for sustainable and energy-efficient building design. And, with Totem’s NOₓ emissions at less than 10 mg/kWh, Travelodge is able to significantly reduce the building’s emissions of NOₓ, a potentially deadly polluting gas that is increasingly driving decision making for consultants dealing with projects located in highly urbanised areas.

Recently highlighted for its sustainability in industry awards, Adveco’s m-CHP application was also used by Bromsgrove Sport and Leisure Centre. Operated by Everyone Active, this was part of a large new build project designed to meet strict building and environmental standards. The new £10.3m facility providing a range of services to the local community including two swimming pools, sports hall and climbing wall, a 100-station gym, a fully-featured spa, and a café. With the pools and associated year-round heat demand, the leisure centre required a high-performance heating system.

To achieve the high level of energy efficiency to serve the building’s heating system required a 25kWe, 57kWTh TOTEM T25 -CHP appliance, as well as a bespoke 3000-litre buffer vessel, controls and ancillaries. Adveco additionally supplied two A.O. Smith BFC120 condensing water heaters to serve the domestic hot water supply to the leisure centre.

Since commissioning in early 2018, the TOTEM T25 at Bromsgrove Leisure Centre achieves 7,000 operational hours a year for an annual saving of as much as £10,000.  By producing both electricity and heat from the same supply of input fuel, the associated net reduction in carbon emissions has been more than 65,000 kg per year.

For leisure projects, high-efficiency condensing boilers and gas-powered m-CHP continue to offer considerable economic advantages in terms of operational costs for built assets. They also remain a realistic and effective means of meeting the demands for improved sustainability, which can be greatly enhanced by combining these technologies with other renewables. Whilst a gas/hybrid approach may be perceived as more conservative, it offers a route to a more sustainable future without removing potentially necessary and therefore valuable energy infrastructure which would be needed to support the introduction of green gas with its lower carbon footprint. Critically, a hybrid approach helps to plan for the future without being prohibitively costly.

Read more about the project at Bromsgrove Leisure Centre

Watch our video on the advantages of micro CHP for commercial buildings 

Bromsgrove Leisure Centre plant room.

Sustainable Energy For The Leisure Industry – Part 1

From hotel accommodation to restaurant kitchens, spas and swimming pools, leisure estates generate a wide range of electrical and heating demands. In terms of usage patterns, demands can be significant, often varied, but also constant, creating a complex range of challenging applications.

Currently, around 40% of UK greenhouse gas emissions are accounted for by heating, cooling, ventilation, the provision of hot water and lighting properties. The impetus then is to reduce operational energy use, prioritising reduction in energy demand and consumption over all other measures. This means in-use energy consumption will need to be calculated and publicly disclosed on an annual basis, as laid out in the new, mandatory Streamline Energy & Carbon Reporting (SECR) regime. This is designed to raise awareness of energy efficiency, reduce bills, and save carbon by driving an increase in renewable energy supply and prioritising on-site renewable energy sources.

From new builds to refurbishment projects, the leisure estate is faced with a myriad of choices, and, if medium or large organisations they are going to be increasingly held accountable by SECR for decisions that must ultimately balance both CAPEX and OPEX with this new sustainability.

A difficult task for an industry where heating and hot water are considered business-critical services and demands in terms of higher temperatures and usage far outstrip anything seen domestically.

The key then is to understand how hot water, heating and power demands can be cost-effectively brought into balance by maximising contribution to a building’s overall efficiency. Identifying technology concepts that help address such sustainability is only half the battle though, there still remains that need to reduce total 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 hot water and heating system.

Innovo commercial water heater by AO Smith

A.O.Smith’s Innovo Water Heater

Adveco's MD commercial condensing boiler

Adveco’s MD. A range of high-efficiency Floor-standing condensing boilers

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 leisure projects that face the most stringent legislation and oversight, high-efficiency condensing boilers, such as Adveco’s MD range, and room-sealed condensing water heaters, such as A.O. Smith’s BFC and Innovo units, remain a realistic and effective means of meeting the demands for improved sustainability.

When it comes to the refurbishing of existing building stock, which is where the greatest advances can be potentially made, installing solar thermal is going to be better from a renewables’ perspective. But we also recognise that this approach can be constrained by limitations of space, delivery timeframes and budget. ROI can also be much slower to achieve, despite the welcome new Smart Export Guarantee (SEG) legislation, under the which SMEs installing new solar photovoltaic panels, will from 2020, be able to profit from exporting excess generated electricity to the grid.

A smart approach would be to combine two heat generators, such as gas and solar, or gas and air source heat pump, although this can generate new issues of logistics, space requirements and increased complexity of plant, leading to a higher CAPEX cost compared to a pure condensing heating system. The advantages for a commercial leisure site from a hybrid heat pump/gas boiler system is the ability to smartly balance the heat generators, guaranteeing all-important high system temperatures while reducing the maximum power consumption for greater efficiencies and lower operational costs.

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.

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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.

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