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TOTEM engine for Combined Heat and Power (CHP).

What is a Micro CHP engine? And How Does CHP work?

Onsite cogeneration of electricity with heat reclaim by Combined Heat and Power, or CHP units, is one of the most effective ways of reducing costs by simultaneously powering and heating a building from a single gas-powered engine.

As gas supply remains on a par with or slightly cheaper than grid-supplied electricity, and because Combined Heat and Power units secure ‘free / waste heat’ as part of that power generation process less gas overall is required for the heating of the building. So there are two opportunities to reduce operational costs.

The micro-CHP form factor that we deploy in the TOTEM series of CHP units was originally conceived and brought to market in the late 1970s. Subsequently, the design has evolved and improved, incorporating the latest engineering practices and expertise from the automotive industry to ensure the design is optimised to meet the real-world needs of a building project.

The TOTEM m-CHP internal combustion engine is a product of the automotive expertise of Fiat Chrysler Automobiles’ (FCA). The continuous development over 50 years, gives the current gas-driven 1.4L Fiat Fire engine an astounding reliability rate of 99.6% over 100,000 units per year.

The Engine Control Unit (ECU), high-efficiency catalytic converter and fine-tuning for the engine’s stationary parameters is provided by Magneti Marelli, a name which will be familiar to fans of Formula One racing. It is the ECU and catalytic converter that which deliver TOTEM’s ultra-low NOₓ and CO emissions. This is particularly important for urban building projects where NOₓ (a combination of NO and NO2) is seen increasingly as a major factor in air pollution which can be extremely harmful to people. As Combined Heat and Power localises energy production, it is critical that the use of the technology addresses and significantly reduces NOₓ generation. NOₓ emissions from a TOTEM unit are less than 40 mg/kWh of electricity output, but once you take the heat output into account, which is considered a waste product, TOTEM becomes effectively NOₓ free.

TOTEM achieves ultra-low emissions rates –  that are less than 10% of most micro-cogeneration units available on the market –  through the close manufacturing relationships, of Fiat, Magneti Marelli, Asja and Adveco which has driven the adoption of micro-CHP in the UK through unique technology and service support. For this work, Adveco has been recently awarded a Frost & Sullivan Technology Innovation Leadership Award for developing commercial micro-CHP in Europe.

TOTEM stands out with its complete, highly compact system in a box configuration, a design-driven by the decision to directly couple the engine to the generator, which is capable of delivering electrical outputs from 10 to 50 kW, and then closely integrate the other components, especially the condensing heat exchangers.

A building’s central heating water is heated directly in two stainless steel shell and tube heat exchangers and a water to water stainless steel plate heat exchanger transferring heat from the engine coolant (used to cool the engine, oil, and generator water jacket) and from the first stage exhaust. By reclaiming heat from every available source, TOTEM micro CHP units achieve a thermal efficiency of 65% or higher depending on the return water temperature. The TOTEM will condensate when the return water temperature is less than 50°C without the need for an additional flue heat exchanger.

Based on today’s fuel costs electricity output from the co-generator will be at a similar cost to electricity from the grid, however for each kWh of electricity generated approximately 2.5 kWh of free, high-grade heat will be recovered. With ultra-low emissions, micro CHP offers a real option, especially when combined in an application that blends renewables to provide a cost-effective and future-proof method for providing the power and heating needs for commercial projects.

Adveco packaged plant room.

Packaged Plant Rooms – A New Paradigm for Site Safety

Adveco discusses how off-site construction techniques for commercial heating and hot water can alleviate pressures of cost and timescale on construction sites whilst also helping improve Covid-19 safety precautions…

There is no doubt that we are going to face long term changes in the way construction projects operate during and in the wake of the current Covid-19 pandemic. Worksites are already having to adhere to stricter policy on where and when workers can traverse and engage on-site, and, in accordance with Government recommendations, the responsibility for their safety lies squarely on the shoulders of the host – not only for incumbent staff but also for any visiting contractors or customers. Ultimately this is all to ensure anyone on site does not become compromised. This means further stretching the usually difficult, and therefore costly, co-ordination of equipment and controls installations required for a building. Such complexity is typical, for instance, when creating and installing modern heating and hot water applications.

New world, new approach

Adopting offsite pre-fabrication as part of your project is therefore highly advantageous, reducing time on site required of specialist contractors, which is both more cost-effective and safer for all involved.

Adveco combines deep engineering understanding with a wide prod­uct offering and experience in full system design to provide a single source of supply for the delivery of complete packaged plant rooms containing heating and hot water systems tailored precisely to fit the specific needs of a project.

All work is carried out in a controlled, purpose-made environment. This means should there be any forced downtime on-site due to a local lockdown, the assembly work at Adveco will continue as planned. With no distractions from other typical construction site activities or issue we can ensure your plant room work is more rapidly progressed and, with a controlled factory environment, optimal manufacturing conditions are provided for quality control. Unlike the general conditions found on a construction site.

Locating all production work offsite also means the plant room element of a project can also efficiently progress at the same time as other groundworks or site installations. As the plant room arrives with all appliances, controls and ancillaries pre-fitted and connected – using stainless steel (heating) or copper (DHW) crimp pipework – as standard, there is no need for extended plumbing and electrical installation. This helps drastically reduce on-site labour demands and allows for more rapid progression of project timescales, despite social distancing requirements.

To achieve the best results, you will need to finalise facets of decision-making relating to hot water, heating or cogeneration of power early on in the project to allow for increased lead-in times. Once production commences it becomes more difficult to accommodate changes to a bespoke pre-fabricated system. This is why Adveco’s expert design engineers will work closely from the start with your project team to accurately size and design a system that meets the exact needs of the project on day of delivery.  All that is required is for flues, external pipework and final electrical connections to be completed on-site.

Adveco has broad experience of developing small to very large packaged plant rooms, embracing a wide range of cost-effective to operate and renewable technologies, from high-efficiency gas and electric boilers and water heaters to heat recovery units, micro CHP, solar thermal and Air Source Heat Pumps (ASHPs). These are all brought together to deliver a wide range of bespoke applications that can transform the operational nature of a commercial property, reducing emissions and improving the efficiency of hot water and heating for lower ongoing costs. The fact that these systems can also be delivered in a manner that is also much safer for all involved on-site shows the tremendous advantages to be gained from this approach.

Discover more about Adveco’s Packaged Plant Rooms

Berry Court care home plant room installation.

The Cogeneration Gap – Part 3 Caring for the Environment

We have considered the reasons for implementing m-CHP in new builds and upgrading care homes. In this third and final blog in the series, we consider one last deciding factor, the environmental impact of local cogeneration…

The carbon savings have long been an advantage of Combined Heat and Power (CHP), and can still be achieved, but that is changing because grid-supplied electricity is getting much cleaner. There has been a strong downward trend in emissions from electricity production since 2014, due to the increases in wind and solar power and the closure of coal-fired power stations. But on average, CHP provides a carbon benefit over the year, though the actual intensity fluctuates both seasonally and daily. On most days where carbon intensity is more than 188g/kWh CHP will provide a benefit. CHP will be carbon advantageous at some times of the day and not at others, but looking at the average carbon intensity of electricity generation from 2013-2017 even in the summer months when demand falls, the carbon intensity never fell below 200g/kWh, so CHP was always beneficial in this period in terms of carbon savings. Carbon intensity of the grid is higher when it is dark and cold, and CHP requires a thermal load to operate so naturally aligns itself with the higher carbon intensity when it provides greatest impact and savings.

In the future smart controls will adapt CHP run times to ensure it operates when it is most carbon advantageous.  For a CHP that runs for 14 hours per day, for example, the smart controls will ensure that the 10 hours when it does not operate align with the clean grid periods and not when the carbon intensity is the highest.

Even so, we recognise that the value of carbon savings with CHP will continue to reduce in comparison to previous years. Instead, attention is now turning to Nitrogen Oxides (NOX) savings. A by-product of the combustion of hydrocarbon fuels, NOX are a major contributing factor to poor air quality, the most toxicologically significant being a combination of nitric oxide (NO) and nitrogen dioxide (NO₂). It can cause lung irritation and respiratory infections as well as being linked to cancer, asthma, strokes, and heart disease. The Royal College of Physicians believes it directly leads to as many as 40,000 deaths each year. This has led to widespread recognition that more needs to be done to address NOX emissions and the care sector needs to be seen to be addressing emissions that are a by-product of its activities.

Although all CHP with a catalytic converter is cleaner than the grid, taking in to account electrical efficiency, the wider CHP industry, as an average, has the same NOx emissions as large scale power generation. The downside for CHP has been that carbon-based power generation historically was located outside of major urban areas, but the drive for low carbon buildings is bringing even more potential emissions into our cities. Most CHP are likely to have a slight positive impact on air quality nationwide, but because those installations will typically be in urban/residential areas that CHP will have a negative impact.

Therefore, localised NOX emissions from ‘dirty’ cogeneration is becoming a concern. Where CHP is used to offset condensing boiler run hours, if the CHP is dirtier than the condensing boiler then the local emissions are worsened. Despite air pollution and NOX mainly arising from road traffic – half of current NO­X pollution in major urban areas is attributed to vehicles – emissions from decentralised energy production are now being seen as a contributing factor. It is therefore of great importance that the NOX emissions from new CHP units are lower than condensing boilers if they are to have a positive effect.

Our own assessment of cited NO­X emissions from CHP manufacturers shows wildly fluctuating numbers, ranging from 64 mg/kWh to a highly concerning 596 mg/kwh, and older units were far worse. Consider the 2018 EcoDesign limit for CHP is 240mg/kWh! And I would argue that this number is now far too high given the changing attitude to, and awareness of the dangers of NO­X emissions.

Despite heat recovered by the CHP being considered NOX neutral, it is vitally important to recognise that there is a considerable difference between ‘dirty’ CHP and the latest generation of low-NO X CHP. One such class of low-NO X appliance are the micro or m-CHP units, where we can cite emissions levels as low as 11mg/kWh. For a unit of 20kW electrical output, with a gas input of 70kW, in a situation with an average annual run time of 6,500 hours for a standard application such as a care home, the yearly NOX emission from a ’dirty’ CHP will be 109.2kg/year, compared to 4.55kg/year for the latest generation of m-CHP. And remember, this option is also improving local air quality because the m-CHP is used to offset the run hours of a condensing boiler which at emissions over 30 mg/kWh is dirty compared to the CHP.

Conclusion

Comparing CHP with other local energy generation technologies, today we can still show that it has lower running costs than a heat pump, plus has both higher savings and an easier install than PV. Without doubt, a CHP can provide useful energy cost savings for a building, so it always makes sense to run existing CHP, and makes sense to purchase for the right type of building.

Mid to high occupancy residential care homes are particularly apt and upgrading to CHP in these facilities will provide a good payback period and be a solid investment over the decade, so long as a guaranteed maintenance schedule is put in place.

Finally, selecting the right CHP can provide carbon savings and more importantly, as we look to the future, can help improve local air quality for a building.

At the end of the day, the building and its use should drive the decision making, but for the care home, perhaps the greatest advantage of all is the assurance that residents will have a continuity of comfort through the provision of heating and hot water. It is in this role that m-CHP delivers a business-critical need in the care home environment.

TOTEM T20 CHP unit (Combined Heat and Power unti) in a residential care home.

The Cogeneration Gap – Part 2 Embracing CHP

In the first part of this short blog series on the application of micro-CHP within residential care homes Adveco explained why CHP (Combined Heat and Power) is often chosen for new builds. In this second part, we turn our attention to why you would upgrade existing facilities to m-CHP…

The cost of deploying CHP within care homes is, without doubt, the deciding factor for the majority of managers. When calculating the operational cost savings, we need to take the cost of the offset electricity and thermal energy, and deduct the costs of the energy coming in, in other words, the price of the gas, and the maintenance costs. The other key input is the number of run hours per year that the CHP appliance will operate.

A CHP is very different to a boiler, which other than an annual service you would typically tend to forget about. Inside the CHP casing is a gas-powered automobile engine, with high stressed moving parts that will require necessary repairs over time that could reduce savings. So, you need to be aware of the ongoing investment needed when operating CHP to support regular pay as you go maintenance and repair. Once the cost of maintenance is factored in, the operating costs can be determined based on electricity and gas prices.

To understand what these operational costs look like, I am going to cite current figures based on the installation of a TOTEM T25 micro-CHP unit. From our experience, these are typically the size of a unit a larger care home will install. Firstly, being gas-powered, the CHP is a far better option when the cost of gas is less than electric, which has been the trend since 2015. Currently, based on medium non-domestic rates, a T25 will save £1.50 per hour that it runs. Let’s consider the expectation on run hours per year, many CHP units that have gone in will run relatively short hours per year just to increase the efficiency of the building to meet carbon requirements. Looking at the demands of the London Plan, for example, 2,500 run hours may be sufficient to meet the additional carbon savings demanded. At that lower run rate, the CHP is still going to save £3,750 savings per year.

This may not be enough to provide a true payback, but are interesting savings in an inherited, new building, where the cost of the CHP is part of the cost of the building and does not have to be proven to pay back. The decision is only to run it and save £3,750, or not and save nothing.

Upgrading to CHP

But what if you want to upgrade your plant room, when is right to Include CHP? The technology offers a number of advantages, the micro-CHP is especially easier to install, passing through a standard 60cm doorframe and able to be installed internally, avoiding the need for external space or rooftop placement which would be needed for say solar photovoltaics (PV) which is another common choice for onsite energy generation. CHP also offers better payback than Air Source Heat Pumps (ASHP) and with inclusion in the Government’s new SEG payments, you can profit from additional energy generated by selling it back to the grid from your CHP at a guaranteed tariff. There is also the bonus of increased resiliency for your DHW and then there are the running cost savings.

The cost of a T25 is £50,000, with savings per hour (including maintenance) of £1.50, so it requires 33,333 run hours to achieve payback. Saving just £3,750 per year means the only driver is carbon savings and that would not alone warrant the investment in an existing building.

If the building is right for CHP, then it is worth considering as an upgrade. CHP saves money when it runs, it’s the opposite of a boiler which costs money when it runs so we want that to be off and the CHP on.  The ideal applications are ones with large DHW loads where people are residing. With a large care home, the expectation would be to run a CHP 24 hours per day during the heating season, dropping to 12-14 hours per day outside heating season. This gives us an average running of 18 hours per day throughout the year or 6,700 run hours per year. That equates to a five-year payback, and with 10-year  operating plan in place the potential savings will be £50,000 if your building is suited to the technology.

Alexandra House, operated by Care South, is a two-storey, 58-room residential care and nursing home in Poole, it has a T20 CHP working in conjunction with a custom-built 2500-litre buffer vessel, as well as a cascade of two AO Smith Upsilon 110 boilers and two AO Smith IT500 indirect calorifiers. This is all supplied as a complete package, alongside ancillaries and backup heating components via electric immersion elements. The design of the hot water and heating system at Alexandra House is projected to achieve more than 7,100 CHP run hours per year, resulting in annual carbon reductions in excess of 44.5 tonnes and providing expected energy savings, inclusive of CHP maintenance costs, of £7,500.

In the third, and final part, we will take a look at the environmental impact of m-CHP and explain how it can deliver energy and heat whilst reducing a care home’s emissions…

CHP for residential care homes (Combined Heat and Power).

The Cogeneration Gap – Part 1

Often seen as an ideal application within the residential care home, in this short blog series Adveco discusses the argument for onsite energy cogeneration, the operational costs, the environmental impact and highlights the increasing performance gap between ‘dirty CHP’ and the latest generation of highly efficient micro-CHP…

Whether building a new residential care home or refurbishing an older property to be fit for purpose, the importance of energy provision has risen up the agenda, resulting in a proliferation of on-site power generation. According to a report by Centrica Business Solutions (The Energy Advantage Report, June 2018).

“…more than 80% of commercial operations are expected to invest in on-site power production to generate up to a quarter of their electricity requirements by 2025.”

One popular choice has been the deployment of combined heat and power (CHP), also known as cogeneration. This is the simultaneous production of usable heat and electricity from a single process and source of fuel (typically gas) and is one of the most effective methods available to significantly increase the energy efficiency of a building. With an engine directly coupled to a generator, similar levels of efficiency to that of a conventional source of power can be achieved, and by locating such an installation on-site at the point of consumption, the usual energy losses associated with power transmission through the grid are eliminated.

Additionally, thermal energy is extracted from the CHP process by recovering the waste heat produced by the engine and generator during the power generation process. This drastically reduces the amount of fuel energy lost to the environment as exhaust, instead using it to contribute towards a local heat demand. With a significant continuous demand, such as would be typically seen in a residential care facility a CHP unit can run for very long periods of time and thus drastically reduce the reliance on conventional boiler technology and improve the overall efficiency of a building, reducing emissions and making financial savings.

Understanding the advantages of CHP

For operators and managers of care facilities, there are two basic questions to ask. If you have CHP what should you do with it? If you don’t, should you upgrade your plant room to include CHP?

I want to make it clear that in my opinion there are enough benefits that you definitely want CHP, but you may not want to buy it outright. CHP will have an environmental and cost savings impact in any building, but it only provides a payback case on Capex in the right type of building. That is why you may not want to invest in the technology.

If your building already has CHP it is because someone made the decision to select Combined Heat & Power based on either a financial or an environmental reason. But there are notable differences in between those who design, and those who operate the building.

Designers have historically chosen CHP based on carbon savings requirements from things such as Part L, or the London Plan, which other UK cities will mirror, rolling out their own equivalent local environmental policy.  Designers need carbon savings to get planning permission for a project to be built. It is the most important thing for the designer, and it is the minimum that must be done to successfully complete their job. That is why the designer selects CHP. If you inherited a building built in the last five years with CHP, then it was probably selected for SBEM carbon savings to meet Part L.

So, in this scenario you have CHP, but if it was installed purely for carbon savings, then we have to accept that may not be the most important thing to the end client and their facilities management team. Foremost is the functioning of the building, so the priority is the reliability of supply of heating and hot water, next is the operating costs of the building, and this is then followed by environmental concerns like NOₓ and carbon emissions.

It needs to be recognised that CHP is a support technology, as opposed to a critical technology. Water heaters and boilers are critical equipment, if they break down it influences the heat and hot water supply to the building, and therefore the comfort and safety of the residents. CHP, like many renewables, makes no difference to the reliability of the supply. Whether it is on or off the building still has heating and hot water. If you have inherited a CHP, then you need to decide what you want to do with it.

Shutting it down is an option. You could turn it off and forget about it.  If you do that then you will pay no maintenance, nothing for energy consumption by the unit and, there will be no loss of heat or hot water supply. You will not have any carbon savings either, but, since the building regulations are not policed you can, unfortunately, do this.

Alternatively, you can pay for maintenance and energy and then start reaping the rewards of operating the CHP. Rather than using just gas or electric water heaters for all the domestic hot water (DHW) needed for washing, cleaning, showers and baths, the CHP will supply heat captured from its operation to warm, or preheat stored water. The CHP can supply as much as 90% of the hot water needed by the care home with the water heaters used to ‘top-up’ the water temperatures and meet periods of high demand for Part L systems. CHP is also a great way to build a guarantee of consistent hot water service. Typically, a care home system will operate two or more water heaters, but should one fail it would result in a reduction in available hot water. With the addition of a CHP able to preheat at least 60% of a care home’s hot water needs, residents and staff should not see any obvious change in their hot water services should a water heater fail.

In part two we will consider the cost of operating CHP and gauging when and if you should look to upgrade to the technology…

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 

Reduce Carbon with Air Source Heat Pumps (ASHP)

Reducing Carbon with Air Source Heat Pumps

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

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

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

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

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

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

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

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

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

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

Learn more about Adveco FPi Air Source Heat Pumps

Packaged plant room

Offsite Construction For Heating – An Educated Decision

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

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

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

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

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

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

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

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

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

Discover more about Adveco packaged plant rooms.

Micro-CHP and The Urban Balancing Act

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

A by-product of the combustion of hydrocarbon fuels, Nitrogen Oxides (NOX) are a major contributing factor to poor air quality, the most toxicologically significant being a combination of nitric oxide (NO) and nitrogen dioxide (NO₂). It can cause lung irritation and respiratory infections as well as being linked to cancer, asthma, strokes, and heart disease. The Royal College of Physicians believes it directly leads to as many as 40,000 deaths each year with an estimated cost of £20 billion to the country in healthcare and lost working days. This has led to widespread recognition that more needs to be done to address NOX emissions with attention more than ever-shifting to encompass the production of emissions from the built environment.

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

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

Setting a new threshold for emissions

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

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

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

Hybrid futures

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

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

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

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

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

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

Discover more about TOTEM m-CHP 

Download the TOTEM m-CHP brochure

NHS sustainability

Caring for our Future

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

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

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

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

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

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

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

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

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

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

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

Learn more about our work for the care sector