Read more about Adveco hot water and heating products and industry news in our blogs – check back for the latest updates to save you money on your heating and get the most efficient systems for commercial or domestic applications.

Thinking About ASHPs

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Air source heat pumps (ASHPs) are a type of renewable energy technology that can be used to heat and cool business properties.

Air source heat pumps leverage well-understood refrigerant circuit technology that is employed in your domestic fridge, but rather than cooling, the system is reversed to extract usable heat. They work by transferring heat from the outside air to the inside, using electricity to power a compressor. ASHPs are more efficient than traditional heating and cooling systems, and they have the potential to save businesses money on their energy bills and importantly will reduce carbon emissions generated by buildings.

The first step is to draw in the outside air. This air is then passed over a network of tubes filled with a refrigerant, which is a special type of fluid that can absorb heat. The refrigerant absorbs heat from the air, which causes it to change from a liquid to a gas. The gaseous refrigerant is then compressed by a compressor, which increases its temperature. The hot, compressed refrigerant is then passed through a heat exchanger, which transfers heat to the water in your home’s heating system or hot water cylinder. The now-cold, compressed refrigerant is then allowed to expand, which causes it to return to a liquid state. The liquid refrigerant is then pumped back to the beginning of the cycle, and the process starts all over again.

At Adveco we use ASHPs to supply preheat heat for domestic hot water (DHW) demands in commercial properties, such as washroom facilities, shower blocks, professional kitchens, laundry, and hot water demands for multiple occupancy sites like hotels, care homes and schools.

As a low-carbon technology, ASHPs are a more efficient and environmentally friendly way to heat water for businesses than traditional gas-fired water heaters and boilers. They can help to offset currently more expensive electricity demands generated by primary heat sources such as electric boilers and in particular immersions which were not intended for extended, regular usage in larger scale systems. Designed and installed correctly, ASHPs will help to reduce carbon dioxide emissions as part of a decarbonisation strategy, but, due to the need to work current iterations of the technology harder to attain higher working flow temperatures needed in commercial applications, efficiency drops and the operating costs of the ASHP unit will climb. Compared to an equivalent gas-fired system, current ASHPs will be more expensive to operate based on current gas and electricity prices.

ASHPs are also relatively expensive to purchase. The government’s heat pump plans are based on market expansion to lower prices as mass adoption takes place over the course of the next decade. However, since the technology employs components that are already mass-marketed by the cooling industry, which far outweighs heat pump sales, the expectation within the industry is for ASHP capital costs to remain relatively static, especially across the commercial sector. Improvements in refrigerant efficiency will increase efficiency and it is hoped reduce the size and complexity of future units which could ultimately help lower purchase costs.  One way to address the capital costs of investing in ASHP is to fully review the water heating system, especially if ASHPs are intended to replace existing gas-fired systems. In many cases, DHW systems are oversized, with multiple ASHPs specified as replacements when a single ASHP for preheat and a lower-cost electric boiler would deliver the same operational needs.

Under the right circumstances, ASHPs can bring multiple benefits to a commercial organisation adding an easy-to-maintain renewable energy source to a building, improving system efficiencies and crucially reducing emissions. If you are considering installing an air source heat pump, there are a few things you need to keep in mind when applying the technology to water heating. Unlike space heating, you do not need to consider the levels of insulation in the buildings, so ASHPs are advantageous for both new build and refurbishment properties.  Second, consider the actual hot water demands of your buildings as this will influence decisions on the size or the number of heat pumps required to meet occupant demands. You want to size a system to meet those demands without oversizing the heat pump which will prove more expensive to buy and operate. For existing properties consider metering usage before committing to a design, Adveco can help with the temporary installation of flow meters, data interpretation and correctly sized design.

For information on Adveco’s FPi32 and L70 ASHP ranges and hybrid systems from Adveco visit our heat pump product pages

Read The Adveco June 2023 Newsletter

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Read the Adveco June 2023 newsletter. This month we take a look at the progression of the UK’s plans for net zero, including renewables contributions to the grid and issues with grid connections. We celebrate another award won for our work developing sustainable products and services for commercial water heating, and a reminder to take advantage of our free CPD seminar. There is also an exclusive first look at our next product line.

Click here to read the Adveco June 2023 Newsletter

 

 

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Condensing boilers reman a viable commercial option

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Condensing boilers sit at the heart of a large proportion of commercial buildings today. More efficient than traditional boilers, condensing boilers capture and use the heat that would otherwise be lost up the flue, making them both more efficient and cost-effective to operate.

They work by using a process called condensation. This process occurs when water vapour in the flue gases is cooled to the point where it condenses back into water. When this happens, the latent heat of vaporisation is released, which can be used to heat the water in the boiler. The latent heat of vaporisation is the amount of heat that is required to change water from a gas to a liquid. It is a very large amount of heat, and it can be used to significantly increase the efficiency of a boiler. This makes these boilers more efficient than traditional boilers because they are able to capture and use this latent heat of vaporisation. This can lead to excellent efficiency gains, such as with the Adveco  AD & MD ranges condensing water heaters and boilers which boast 106% net combustion efficiency, reducing energy costs and emissions via efficient use of fuel energy.

Although condensing boilers currently rely on fossil natural gas as a fuel, the AD, ADplus and MD range all are ready to support a 20% hydrogen blend making them excellent, low-cost to-operate options for commercial sites with large hot water and heating demands, and gateway technology to next-generation green gas-grid fuels. For organisations with properties with a gas connection, Adveco can support refurbishment with a wide-range of condensing gas-fired appliances including the popular BFC Cyclone and Innovo water heaters from A.O.Smith.

Producing fewer emissions than traditional boilers, condensing boilers are a good option for those who want to save energy and money on their bills whilst showing a reduction in emissions that impact air quality and the environment.

Here are some of the benefits of using a condensing boiler:

  • More energy efficient than traditional boilers which can lead to energy savings of up to 30%.
  • More environmentally friendly, producing fewer emissions than traditional boilers, which can help to improve air quality.
  • Comfortable, providing consistent temperature in your facility.
  • Low maintenance, and should require little upkeep beyond annual servicing.

Condensing boilers have redefined water heating, prioritising energy efficiency and environmental responsibility. Adveco, with its unwavering commitment to innovation, continues to offer its range of cutting-edge products that exemplify these principles. By embracing condensing boilers organisations gain a proven technology which effectively reduces energy consumption, minimises emissions, and enhances comfort levels within their buildings, all while taking the first steps towards a net zero future.

Explore Adveco’s range of condensing boilers and water heaters

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Are we on track for Net Zero?

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Researchers from Imperial College London have declared a ‘milestone event’ that seems to place us on track for net zero as one-third of UK electricity came from wind farms in the first quarter of 2023. This is the first recorded time that wind has out-suppled gas.

In the first quarter of 2023, 42% of the UK’s electricity came from renewable energy, with 33% coming from fossil fuels, predominantly gas and coal. As well as wind, solar has also seen significant growth in the UK, with the National Grid confirming that April saw a record period of solar energy generation.

Since new onshore wind turbines were effectively banned in 2015 in England, the great majority of wind generation now comes from offshore wind farms. But with a new relaxation of planning restrictions on onshore wind turbines, the expectations for wind to continue to deliver a greater percentage of fossil fuel-free grid electricity makes the technology a core aspect of UK aims for all of its electricity to have net zero emissions by 2035.

Switching to renewable power, whether wind or solar, is crucial to curb the impacts of climate change. However, it was revealed this month in a BBC investigation that billions of pounds worth of green energy projects are stuck on hold due to delays with getting connections to the grid.

Some new solar and wind sites are waiting up to 10 to 15 years to be connected because of a lack of capacity in the electricity system. The National Grid acknowledges the problem but says fundamental reform is needed as energy companies are warning that significant delays to connect their green energy projects to the system will threaten their ability to bring more green power online.

And electricity only accounts for 18% of the UK’s total power needs. So, are we really on track for net zero electricity generation by 2035? Achieving this requires a considerable uplift in the number of renewable projects – as many as five times more solar and four times as much wind – but these sites can only supply energy once connected to the grid. This issue stems from a grid designed and built to be supplied by a limited number of large coal-powered plants, not thousands of decentralised suppliers seeking connection at a local level. It is estimated that more than 1,100 projects are currently waiting to be connected, and with planning restrictions on wind relaxing many more are now likely to be joining the queue.

National Grid, which is responsible for moving electricity across England and Wales, says it is tightening up the criteria for projects to apply so only the really promising ones join the queue. But a huge new investment is also required to restructure the grid so it can deal with more power sources.

Energy Networks Association represents the UK’s network operators, such as DNOs, which connect people’s homes to the main system owned by National Grid. It says that the government needs to speed up the planning process so electricity infrastructure can be built more quickly. Ofgem says it has agreed to allow the National Grid to raise an additional £20bn over the next 40 years from customer bills to pay for the huge upgrades the grid needs, and later this year the government is expected to announce a new action plan for speeding up grid connections.

Commercial organisations factoring in a 100% green grid by 2035 as part of their decarbonisation strategy may need to start reconsidering their plans. If we cannot rely on the grid being on track for net zero in the next 12 years, then organisations need to look at how they can generate energy demand locally without depending wholly on grid supply, or Distribution Network Operators (DNOs) that bring electricity from the national transmission network to businesses. We also already recognise that electricity is costly compared to gas (by a factor currently of 3.8) and is intrinsically linked as much of the grid electricity is still produced by gas-burning power stations. The hope is that costs will fall as renewable generation increasingly supersedes gas, but if £20bn additional funding is required for grid connection alone surely, we need to factor in additional operational costs for future electricity-based applications which are at the heart of most decarbonisation strategies. In the long run, our energy supplies should be not only greener but also more secure and cheaper, but what can be done in the interim?

This brings us back to wind and especially solar. Both are technologies that are proven, well understood, truly renewable and can be installed on the property to meet or at least offset some of the grid demands of a business. Wind power remains a complex, highly expensive option with long lead times due to planning restrictions and complex build and installation so is not for everyone, and is only really suitable for properties located in more mixed/rural locations. Solar, both PV and thermal is by far the simpler and more cost-effective option. Whilst PV can supply electricity for multiple applications, for water heating solar thermal is the preferred option. By far the most efficient of the two solar technologies, solar thermal requires fewer collectors to generate similar energy to a PV set-up, so is more versatile when working with available roof space on a property and is extremely robust when deploying drain back technology. This ensures operation with low maintenance for a faster return on investment.

To learn more about decarbonisation and getting on track for net zero visit our resource page or read more about solar thermal for commercial properties.

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Carbon Capture

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In part one we considered the role carbon emissions play as a major cause of global warming, we now turn our attention to what can be done to address the reduction of existing carbon dioxide in the atmosphere through carbon capture as part of the process of achieving net zero by 2050.

A promising way to help reduce the amount of CO₂ in the atmosphere and slow the pace of global warming, carbon capture is another element of the wider more comprehensive approach required to successfully address climate change.

It advances the idea of carbon sequestration, a natural process of removing carbon dioxide from the atmosphere and storing it in a way that it will not be released back into the atmosphere for a long period of time. This is observed in vegetation, where plants and trees absorb carbon dioxide from the atmosphere during photosynthesis. The carbon dioxide is stored in the tree’s tissues and is not released back into the atmosphere until the tree dies and decomposes. Reforestation, therefore, has huge value in terms of increasing the amount of carbon that is naturally stored in trees but also soils. Soils can store large amounts of carbon as organic matter, such as compost or manure. Oceans are also a primary natural provider of carbon sequestration, storing carbon dioxide in a variety of ways, dissolving it in the water itself, but also forming carbonate minerals, and storing it in the tissues of marine organisms.

An increasing raft of new technologies is leveraging these capabilities to create commercial-scale carbon capture projects around the world deploying. These projects include:

  • Direct air capture (DAC) removes CO2 directly from the atmosphere. This is done using a variety of methods, such as chemical absorption, physical adsorption, and membrane separation. The captured CO2 is then stored in a variety of ways, such as underground or in the ocean.
  • Carbon capture and storage (CCS) is designed to capture CO₂ from industrial sources, such as power plants and factories. The captured CO₂ is then stored underground in deep saline aquifers or depleted oil and gas reservoirs.
  • Bioenergy with carbon capture and storage (BECCS) is a technology that captures CO₂ from biomass, such as wood, agricultural waste, and municipal waste. The captured CO₂ is also then stored underground.
  • Enhanced oil recovery (EOR) is a method of increasing the production of oil from an oil field by injecting CO₂ into the ground. The CO₂ forces the oil to the surface, where it can be extracted.

There remain a number of challenges associated with carbon capture, such as the cost of the technology, the availability of storage sites, and the potential environmental impacts. The cost of carbon capture still varies greatly depending on the technology and the source of CO₂, however, it is expected to come down as the technology matures. Despite the challenges, carbon capture has the potential to play a significant role in reducing greenhouse gasses and slowing or even halting the threat of runaway global warming.

Read more about net zero and what your organisation can do to reduce its carbon emissions today

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Carbon Emissions And The Commercial Sector

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A major cause of global warming, carbon emissions are the release of carbon dioxide and other carbon-containing gases into the atmosphere. Because these gases absorb infrared radiation emitted from the Earth’s surface global temperatures rise leading to extreme weather events, rising sea levels, and changes in plant and animal life. This has been steadily increasing since the Industrial Revolution when there was a marked increase in the burning of fossil fuels, a process which releases carbon dioxide.

Today the main sources of carbon emissions are:

• Energy production – where burning of coal and gas is used to generate electricity and heat. This remains the largest single source of carbon emissions.
• Transportation – Cars, lorries, aeroplanes, and ships using diesel or petrol derivatives as fuel release carbon dioxide and other greenhouse gases
• Manufacturing, agriculture, and other industrial activities – release carbon dioxide and other greenhouse gases as a by-product of their operations
• Deforestation and other changes in land use – agriculture and development, can release carbon dioxide that has been stored in the soil and vegetation

So What Can Be Done to Reduce Carbon Emissions?

There is no single silver bullet to address the reduction of carbon emissions, although attempts to tackle the main sources of carbon generation as outlined are much more likely to deliver a notable and faster impact. Carbon generation is however so prevalent that multiple approaches need to be adopted in conjunction to halt or at least slow the damaging impacts predicted and that we are already experiencing around the planet.

Switching to renewable energy sources such as solar and wind-generated power is given, alongside greater improvements in energy efficiency of businesses, and appliances deployed.

Social change is also required, with greater dependence on more energy-efficient public transportation or actively opting to drive less and walk more. Addressing diet has been proposed since meat production is a major source of greenhouse gases. Recycling is also critical in reducing waste that goes to landfills, which in turn reduces the amount of methane gas that is released into the atmosphere. Better management and planting of trees that absorb carbon dioxide has also been long recognised as a proactive and environmentally friendly option. The problem is that this has been used to deflect a lack of active effort to reduce carbon by organisations through the action of offsetting.

Carbon offsetting

Carbon offsetting is a voluntary market-based mechanism that enables organisations to compensate for their greenhouse gas emissions by supporting projects that reduce or remove greenhouse gases from the atmosphere. The goal of these projects, which can be located anywhere in the world, is to match in reduction of what a company is producing in terms of greenhouse gases in the atmosphere. The problem is the organisation is failing to address the root causes of its own carbon emission activity. Also offsetting in projects geographically distanced from an organisation’s own carbon generation is likely to have a more limited impact.

Carbon offsetting is not a substitute for reducing emissions, and can quickly become a means to counteract poor efforts to amend organisational activities that actively generate carbon emissions, such as legacy industrial functions and unnecessary business travel. As a result, carbon offsetting becomes regarded as little more than corporate social responsibility activity which many governments have now rightly called out as little better than whitewashing.

Whilst larger, listed organisations will be held accountable in the UK and precluded from citing offsetting over actual investment in sustainability, the processes used to offset carbon emissions remain valid and can be used as a guide for delivering real change in business practice.

Planting trees, investing in renewable energy projects, improving energy efficiency in businesses, supporting sustainable agriculture practices, such as crop rotation and cover cropping, and methane capture and storage all have a role to play in helping to mitigate the effects of climate change are all valid, sustainable activities if employed as part of a wider decarbonisation strategy. But that strategy must seek to actively reduce an organisation’s emissions to the point where net zero is attainable across the entire corporate structure, from industrial processes to buildings and transportation.

Active reduction of carbon generation is the ultimate goal, but the issue of existing high levels of greenhouse gasses in the atmosphere means that there is also a great deal of interest in technologies and processes that can actively capture and remove carbon dioxide from the atmosphere.

In part 2 we consider a future based on carbon capture…

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Read The Adveco May 2023 Newsletter

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Read the Adveco May 2023 newsletter. We start the month with a look at the government’s plans to Power Up Britain, before turning our attention to the options and pitfalls that should be avoided when planning a move to more sustainable water heating in commercial buildings. We also have launched a new training portal on our website with a new CPD for solar thermal specification and installation training.

Click here to read the Adveco May 2023 Newsletter

 

 

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All Electric ? Sustainability & Water Heating Pt.3

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In this three-part series, Adveco has so far addressed the role of air source heat pumps and solar thermal as a source of low carbon preheat, in this final part, we consider the future of gas and the adaptation to all electric applications for implementing more sustainable hot water in commercial buildings.  

Read Part 1 Sustainability & Hot Water – Which Path Is Right For Commercial Properties? 

Read part 2 sustainability & Hot Water – Using The Sun

Despite the pressure to address carbon emissions in building stock in the UK, the fact is we are still waiting for clear advice at a government policy level. The final decision on energy solutions remains unresolved. So do you opt to go all electric with equipment now on the basis that the grid will become zero carbon or hold out for the option of carbon-free gas such as Hydrogen, which in terms of infrastructure change and refurbishment would be potentially quicker, cheaper and less disruptive.

As indicated, if your building has a gas connection and has high hot water demands it remains the most cost-effective option. Additionally, new gas-fired appliances operate with ever-reduced emissions, and most are ready to accept the initial proposed 20% hydrogen blends in the gas grid as early as 2024 without requiring any alteration. ‘Hydrogen Ready’ units are, with a replacement of the burner and pre-mixer, even capable of burning 100% hydrogen, but that scenario is some time away. Should hydrogen be accepted by the government as a function of net zero we would not expect 100% feeds to be in place nationally until 2040 with the grid changeover beginning in the early to mid-2030s. Retaining an existing gas connection, therefore, provides a degree of futureproofing should green gas technology be embraced.

What is clear though is that the latest building regulations (Part L, 2021) have radically revised the carbon intensity of electricity from 519g CO/kWh ten years ago to just 136 today. Gas in the same period has fallen from 240 to 233. Whilst the regulations do not yet exclude gas, they do advantage the adoption of all electric systems. We have demonstrated that renewables have a critical role in reducing the carbon emissions of a system, as well as offsetting the costs of heating water with direct electricity.

Gas-based hot water applications are, by a factor of 3.8, currently cheaper to operate than direct grid-electric systems. Using heat pumps can offset 25-35% of those energy costs, but this still leaves a considerable excess operating charge because of the need to provide top-up energy for safe operating temperatures. Historically, additional system top-up was provided by electric immersions, which for backup purposes and occasional peaks in demand whilst more expensive was acceptable. The shift to fully electric systems has put a greater onus on the technology which was never designed to provide primary heat. The costs are excessive and as we indicated, should they be deployed hard water, can rapidly develop scale leading to permanent damage in a remarkably short time. For this reason, we recommend the replacement of immersion technology with smaller electric boilers that are both more efficient, and, because they operate in a closed loop will avoid the issues of systems scaling up.

Perhaps the most detrimental issue we see today as a result of replacing gas with electricity is the propensity to oversize the new all electric system, replacing gas appliances with electric alternatives with like-for-like capabilities. Hot water systems have been inherently oversized in the past through a lack of understanding of application design or concerns over providing suitable backup to ensure system continuity. The result of oversizing is however always the same, unnecessary capital costs for system supply and installation, but when replacing gas with electricity, oversizing leads to greater electrical demand and should that exceed a building’s available amperage of electrical supply, project installation costs will inevitably soar, or even stall the project.

This can best be avoided by understanding your building’s actual hot water demands and designing the replacement to meet those specific needs. There is an art to designing hot water systems, but real, actionable data is priceless. When considering options for introducing sustainability the best advice we can give is to understand your needs first. Live metering is an easy, non-intrusive way of securing the valuable operational data you need to make informed decisions that deliver on expectations to lower carbon emissions without incurring unforeseen costs.

 

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Using The Sun – Sustainability & Water Heating part 2

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In this three-part series Adveco considers the choices available to commercial organisations that wish to advance decarbonisation strategies in their buildings through the implementation of more sustainable hot water. In part 1 we considered the role of air source heat pumps as a source of low carbon preheat, now we turn our attention to using the sun with solar thermal systems…

Read Part 1 Sustainability & Hot Water – Which Path Is Right For Commercial Properties? 

Using the sun to generate free heat from solar energy is a well-recognised and proven route for introducing renewables into a building project. As a high-temperature renewable source of hot water, solar thermal lends itself to working in conjunction with not only conventional gas heating but also other renewable technologies including air source heat pumps which can be used to provide pre-heat to solar thermal. This enables a variety of hybrid applications to be considered to meet the varied demands of commercial buildings.

Solar thermal systems are ideal for businesses that use and rely on large amounts of hot water, but it is important to understand that a solar thermal system will not fully replace your existing water heating system and will not provide space heating.

All areas of the UK are suitable for using the sun through solar energy technology; however, solar insolation, the energy generated from sunlight within collectors, will decrease as the sun’s inclination falls in the winter months and this is affected by how northerly located a building is in the UK as well as cloud cover. When it comes to using the Sun, solar thermal systems are obviously most productive in the summer months, when there is most sunlight, resulting in the additional need for either non-renewable energy sources or heat pumps which will still generate usable year round, even if ambient outside temperatures drop to -20°C during the winter months.

Shading from neighbouring buildings or tall trees, for example, can also greatly reduce a solar system’s output in which case a commercial air source heat pump would be a preferred alternative to produce low-carbon heat energy.

The actual percentage of your water heating demand covered by solar thermal will depend on your site and energy consumption habits (though this figure is typically around 30% for commercial sites). A south-facing and unobstructed roof with an inclination of 30° from the horizontal is optimal, though by no means essential as solar collectors can be installed in a variety of ways: built on the roof; built in roof; mounted on walls or on a frame construction to achieve inclination on flat roofs.

Sized and installed correctly, a single solar thermal collector can contribute up to 1400kWh per annum, providing electricity savings of £300 and more importantly reducing emissions of CO² by 322kg.

It is important to recognise that solar thermal differs from solar photovoltaic or Solar PV as it is known. Solar PV uses solar cells in a panel to convert the solar energy into electricity that can be stored, used as required, and even be sold back to the grid. Solar thermal works by a process of fluid heating in the collector panels that is then transferred via indirect heating in the cylinder into the hot water system.  This requires basic plumbing for its installation and a minimum 3m drop to ensure flow. This does mean it is really only suited to installation on a building, rather than in the grounds, although that helps reduce the threat of vandalism compared to frames installed on ground level.

Giving consideration only to the hot water system, solar thermal is still more advantageous compared to equivalent-sized solar PV systems. For example, a 4kW solar PV system and the equivalent solar thermal system will cost almost the same to purchase and install, with minimal operational costs, but solar thermal will exhibit a much smaller physical footprint. A typical 4 kW PV system would require 16 collectors at 25m², whereas this would be matched by just three solar thermal collectors for a total footprint of 6.6m². This makes solar thermal a better choice for buildings with reduced roof space, especially if sustainable projects are intending to introduce a mix of solar thermal, heat pump and solar PV. The silent operation of solar is also a consideration factor.

To ensure system longevity and return on investment, fluid within the solar collectors must be correctly managed. If left in the panel it can overheat, stagnate and leave collectors irreparable. This can be avoided by incorporating Drain Back into solar system designs. This gravity flow approach reduces pump capacity requirements and energy use of the pump station to a minimum and will automatically drain fluid if power is cut without the need for working components. This makes solar thermal systems with drain back low maintenance with long operational lifespans. Fluid refresh is, on average, required every eight years but may last much longer.

Certain commercial system designs can demand a minimum of 45°C of preheat which, due to annual variation in production, could preclude the use of solar thermal as a lone preheat source. This does match the minimum working flow temperature for preheat that would be designed into a system utilising the current generation of air source heat pump.

Under such conditions, a typical sustainable application would see a cylinder sized to meet the storage requirements of the building’s hot water demands with the heat coming from a combination of an air source heat pump and solar thermal collectors working in conjunction to guarantee the preheat temperature. The heat pump, operating at optimal efficiency at lower temperatures will preheat the 5°C cold feed to 45°C at which point the solar thermal is employed to further raise temperature to 50 or 60°C depending on the time of year. Working together the renewables can offset the majority of the electrical costs otherwise required to heat the water, even during periods of peak demand.

Using the sun to provide energy to preheat a hot water application or top-up preheat in a hybrid hot water application is truly advantageous, but is not a singular response for the total hot water demand in commercial organisations.  In the third and final part of this blog series we will we consider the future of gas and the adaptation to all-electric applications…

 

 

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Sustainability & Water Heating

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In this three-part series on sustainability & water heating, Adveco considers the choices available to commercial organisations that wish to advance decarbonisation strategies in their buildings through the implementation of more sustainable hot water.  

In this first part we consider some of the basic constraints of designing water heating applications, the technology available and the role of air source heat pumps…

Which Path Is Right For Commercial Properties?

Estimates vary, but it is generally accepted that buildings are responsible for as much as 50% of the nation’s carbon emissions, with much of the existing building stock still dependent on gas, which, while increasingly efficient to use is a ‘dirty’ fossil fuel. Daily hot water usage can potentially account for as much as 30% of a commercial building’s daily energy demands so is a notable component of an organisation’s emissions. So sustainability & water heating go hand in hand, and the latter should be one of the first considerations within a decarbonisation strategy.

The relatively lower cost of gas compared to grid electricity, and the necessary high working flow temperatures it delivers have therefore made it historically the energy of choice. This becomes problematic if sustainable operations are now the goal. As a matter of course, new builds, unless exhibiting large demands for gas, will struggle to receive permission (under Part L of the building regulations) for a new gas connection and as a result, are going ‘all electric’ for heating and hot water. With modern construction fabric and insulation, this approach can pay dividends. For legacy properties requiring refurbishment, the choices become more problematic, especially for space heating where modern low-temperature systems need replacement pipework and heat emitters or will fail to deliver. Though this is not an issue for replacement hot water, the complexity of both new build and refurbishment can still suffer costly pitfalls in the drive to sustainability. With electricity on average currently costing as much as 3.8 times that of gas, serious consideration needs to be given to a selection of technologies available to ensure that any changes to a hot water system balance the carbon reduction with the capital and operational costs.

The Options For Sustainable Water Heating

There are several options when it comes to implementing a hot water system and as we have intimated some are driven by finance others by the desire to be environmentally aware. Other factors though can include everything from geology to available space. A building’s location will instantly direct certain decisions as the hardness or softness of the water will impact options. For instance, stainless steel cylinders will be preferential in soft water areas as they are resistant to the corrosive nature of the water, whilst lower-cost glass-lined vessels are preferable in harder water areas. However, high-intensity heating, such as delivered by electric immersion can be extremely detrimental in hard water regions, accelerating limescale generation to the point that it can irreparably damage a system in a matter of months if not correctly maintained.

That does not preclude electricity as a choice, but it does affect how applications should be designed. The real leading question is do you choose gas or electricity? If gas, do you opt for direct or indirect heating systems or if electricity do you choose immersion or electric boiler as your source of thermal energy? Whichever route you decide upon, your system will additionally require a low-carbon heat source which will preheat the water reducing the energy consumption of the water heater, and in turn, reduce carbon emissions and the running costs of the water heater.

There are several choices for securing low carbon heat, including biomass; combined heat and power (CHP); ground or water source heat pumps; air source heat pumps (ASHP), solar photovoltaics (PV) and solar thermal.  Through a mix of cost and simplicity, the best technologies to use for domestic hot water (DHW) systems are either ASHP or solar thermal.

Heat pumps are a technology that operates most efficiently at lower temperatures, making it highly applicable to domestic applications, but commercial DHW systems require 60°C working flow for safe operation and anti-legionella processes. The heat pump can be pushed to deliver a higher percentage contribution, generating temperatures of 45-50°C for preheat, but this at the cost of performance efficiency, requires electrical energy, and that has operating cost implications. Compared to an equivalent-sized direct-electric (ie, from the grid) system, one with an ASHP can achieve carbon reductions of 42-47%, whilst saving 25-35% of the energy costs. The system will still be required to top up heat to the necessary 60°C, using either immersion or an electric boiler. This, combined with the heat pump’s reduced operational efficiency means it will still be much more expensive to run than an equivalent-sized gas-fired system based on a modern and efficient (109% net) water heater.

The recommendation, in this case, is to keep electrical demand down by increasing the size of the hot water storage which is then heated more slowly. This is very different to the high energy input, low storage seen with gas-fired systems. A 30kW energy source can heat 750 litres/hour by 34°C, so when the system draws hot water at a faster rate than it can be heated to 44°C for hot showers you start to get complaints that the water is ‘cold’. The larger volume cylinder helps to overcome this undersizing allowing for a two-hour reheat cycle that maintains enough water at 60°C to meet daily demand, whilst slowly heating reserves through the night when demand is minimal to meet the morning peak.

Despite gaining improved sustainability & water heating modernisation the carbon savings and costs no longer align.

Even with an ASHP operating at optimum efficiency (for 35% recorded reduction in energy) costs would be close to three times that of gas alone, so it is inherently important to consider the nominal value of the carbon reduction when planning a refurbishment from gas to electricity.

However, we can still take advantage of solar thermal which can be employed to offset energy use in gas-fired systems as well as offsetting costs in electric/ASHP applications.

We will discuss this further in part 2