F-gases in refrigerants are known contributors to global warming, and the EU F-gas Regulation 2024/573, which came into force on 11 March, aims to further curb the use of refrigerants with high GWP. The regulation mandates that, from 2027, chiller, air conditioning and heat pump systems under 12kW must have GWP limits of 150, and, by 2032, there will be a full F-gas ban in these systems. From 2027, larger split systems and chillers must have a GWP below 750.

This is part of wider plans to end the use of F-gas, with the EU parliament voting in January to phase-out HFCs, which make up 90% of F-gases, by 2050. This will be enforced by the reduction in HFC quotas set out in the revision of F-Gas III (EU) 517/2014. From 2025, the quotas allocated for HFCs by the European Commission will lead to a reduction of 22% compared with 2024, rising to 12% from 2036. This will result in price rises for remaining refrigerant, which the EU hopes will incentivise a move to low-GWP systems.

The UK is currently drafting its own legislation to align with these rules. It is expected to publish a stakeholders’ consultation document this summer, with a draft regulation published in the autumn.

The Net Zero Carbon Buildings Standard (NZCBS), due in the autumn, will also place limits on the GWP of refrigerants used. A consultation proposed a maximum GWP of 675, which is the GWP of R32, a common refrigerant. It also proposes that refrigerants be accounted for within embodied carbon calculations.

The regulations are driving demand for systems using natural refrigerants, such as ammonia, propane and carbon dioxide, which have near-zero GWP. This is the experience of Edoardo de Pantz, managing director at Acquaria, which manufactures propane (R290) heat pumps and chillers. ‘The market is running faster than the regulations are. The whole supply chain is asking for near-zero GWP heat pumps,’ he says.

BESA technical director and Institute of Refrigeration president Graeme Fox says the upcoming ban on high-GWP refrigerants has led to a sharp uptick in propane systems.

Propane has higher flammability than higher-GWP refrigerants, with an A3 safety classing, and Fox says installers will need to upskill to work safely with the refrigerant.

The EU F-gas regulations state that installers will need a refresher course within five years of the implementation date of the latest regulations (April 2029), and every seven years thereafter. But Fox notes that small systems with a GWP of more than 150 will be banned within three years – before the date when installers have to complete the course. He says manufacturers may stop supplying higher-GWP equipment, even before the implementation date

‘Technicians could be installing highly flammable refrigerants before they’ve had the necessary training, which is very much a concern to the industry,’ says Fox.

In response to the lack of awareness around propane, BESA has published a technical bulletin on R290 in air conditioning equipment and its practical application. Fox says R290 air-to-water monobloc heat pumps designed for housing need special consideration. The refrigerant’s flammability means it must be more than 1.5 metres from an openable window or door, according to manufacturers, says Fox, and because it is heavier than air, it must be more than 1.5m from air bricks and downpipes, to prevent leaking propane from infiltrating the house.

‘In most houses, you’re going to really struggle to get anywhere near the outside of that house and avoid an air brick by 1.5 metres either side of the unit,’ says Fox.

There are also implications for the retrofit of split air conditioning heat pumps in retail outlets or office applications, he adds. A typical application in these sectors is a grid of R407c condensers placed about 300mm apart, perhaps on a gable end. Currently, if one unit fails it can be replaced a similar unit, which is fairly straightforward.

However, it would be impossible to swap in a propane unit, because older units use A1-rated refrigerant that does not require Atex-rated electrical equipment, such as fan motors and electrical meters, so the neighbouring unit is a potential ignition source. (Atex is the name given to the two European directives for controlling explosive atmospheres.) ‘There are very serious implications for retrofit and retrospective repair work with the location of these new units,’ says Fox.

The issue can no longer be left to the AC contractor, he adds, because – under the Building Safety Act – the principal designer has to take responsibility: ‘They have to be aware of it.’

Currently, the European standard BS EN378 governs the safety and environmental standards of air conditioning, refrigeration, chillers, and heat pump systems, and this can be used with three EN60335 product standards that provide more specification details. Several CIBSE guides refer to BS EN378, including AM17 and Commissioning Code R, Guide B and Guide B3. A new version of the European standard is expected later this year (see page 13 to find out more about EN378).

An area Fox believes the EU has overlooked is the application of systems in airports, railway stations and military bases, where flammable A3 refrigerants cannot be used because of the danger of ignition – via sparks from trains and tracks, for example.

‘The EU has a line in the regulations that says higher-GWP refrigerants, such as 410a, can be used if safety standards don’t allow A3 refrigerants, but there’s no point having the exemption if you can’t get the equipment because the quota for these refrigerants is reducing so quickly,’ he says. ‘There needs to be a mechanism to bypass the quota and supply that equipment in these locations.’

For propane chillers, Fox says that – in addition to leak detection and good ventilation – the designer would have to ensure that fans, leak detectors, lights, switches and any power points are Atex-rated.

He is hopeful that issues identified with the latest F-gas regulation will be fed back into the UK’s upcoming consultation document.

‘Just because something is technically feasible doesn’t mean it’s practically applicable,’ he says. ‘We have to be aware of the nuanced application issues that engineers have on the ground.’ 

The post Safe and practical applications: natural refrigerants appeared first on CIBSE Journal.

As in the past few years, CIBSE has reviewed last year’s awards entries to assess building performance across the projects, as well as the quality of the information provided.

In 2021, based on a review of all past entries, CIBSE introduced a data form to accompany the Project of the Year entries, to improve the consistency, quality and coverage of the building performance data provided.

This helps the judging process, and contributes to industry’s understanding of current best practice, in turn feeding into CIBSE activities such as the Net Zero Carbon Buildings Standard (NZCBS).

Since then, entries have been reviewed every year, and updates made to the data forms to reflect evolving practice and improve clarity and data collection.

Quality of data

This year’s analysis confirms that the quality and scope of building performance data continues to increase. The award entries show fewer areas of data uncertainty, more consistent information, and wider coverage of building performance.

While a large proportion of buildings entered into the awards have onsite generation, the energy flows associated with the building and onsite systems are better reported than in previous years. This indicates better metering set-ups, as well as better monitoring and analysis.

SGA Consulting was crowned CIBSE Building Performance Champion for its retrofit of York Guildhall

In recent years, few entries had complete and reliable enough data to estimate the building’s energy use intensity (EUI) with reasonable confidence, but, importantly, this is now possible for the majority of entries.

What the data tell us

Last year’s data shows trends in delivery processes applied across the projects, similar to previous years. As expected, projects often used energy performance modelling (rather than just compliance modelling) – for example, Passive House Planning Package (PHPP) or CIBSE TM54 more generally. Many of them set energy performance targets beyond regulatory compliance, sometimes as contractual targets. They carried out post-occupancy evaluation, with attention to energy use as well as factors beyond it, such as indoor air quality, temperature monitoring, and interviews or surveys of occupants.

The new-build entries had lower energy use than the average building stock, sometimes significantly so; however, energy use was still higher than industry targets from the RIBA 2030 Challenge and LETI for the sectors where these targets are most established, such as homes, offices and schools.

In future years, the NZCBS, due for beta release later this year, will provide a further point of comparison, applicable across a wide range of sectors.

The majority of projects, and all the new-build ones, had onsite photovoltaics (PVs) – in some cases with significant export as well as self-use. The contribution of these PV systems varied significantly across projects, on average around 60-70kWh/m² per yr building footprint (ranging from 35 to 140), covering, on average, around 30% of the building’s annual energy use (ranging from 5% to 55%).

For comparison, in last year’s Technical Update Consultation, the NZCBS proposed an approximate target range of 80-120kWh/m² per yr for non-industrial buildings; this was only a draft and is being reviewed ahead of the beta release.

CIBSE looks forward to your entries, and wishes you all the best of luck!

To enter visit www.cibse.org/bpa

The post Building on performance: CIBSE awards analysis appeared first on CIBSE Journal.

It won Project of the Year – Leisure at the 2024 CIBSE Building Performance Awards with judges impressed by its careful, low carbon design and application of technology.

What’s more, the performance data has been used as an exemplar case study by the UK Net Zero Carbon Buildings Standard, to help establish a best-practice benchmark for operational and embodied carbon for future leisure centre buildings.

To achieve this remarkable feat, building services engineers Max Fordham – working with architects FaulknerBrowns, the client and main contractor – have taken every design decision as an opportunity to minimise energy consumption further.

As such, the building incorporates a range of passive and active environmental technologies, including the extensive use of daylight and mixed-mode ventilation. In addition, heat is provided by air source heat pumps (ASHPs) incorporating load-shedding controls, while the complex is crowned by a giant biosolar roof that provides up to 20% of the building’s electricity needs.

The £57m sport centre’s low-energy design is a response to the university’s campus energy and sustainability masterplan. Developed by Max Fordham under a previous project, the masterplan includes a requirement for all new buildings to achieve Breeam Outstanding and a Display Energy Certificate (DEC) ‘A’ rating in operation.

Large rectangular rooflights supplement daylight in the pool area

To achieve DEC ‘A’, the design had to target a maximum EUI of 218kWh·m^-2 per year. Ambitiously, Max Fordham set out to meet this already challenging target without the use of fossil fuels. ‘When we started to develop the design in 2016, gas boilers were the standard solution, but we said “this building is not going to complete until 2022, when Grid carbon will be lower, so we should not be basing our design on fossil fuels”,’ says Mark Palmer, director and sports leader at Max Fordham. Opting for an all-electric solution would also ensure the building’s carbon emissions fall further as the Grid continues to decarbonise.

The university’s brief to the design team was for a sports centre with a 25m swimming pool, an eight-court sports hall, 175-station fitness suite, climbing wall, ski simulator, and fitness studios, along with offices and teaching spaces.

Palmer says the starting point in developing the building’s form was to separate the swimming pool from the ‘dry’ areas (the sports hall, fitness suite, and so on), so that the circulation space between can form an environmental buffer zone.

Unusually, the design places the sports hall on top of the ground-floor fitness suite and changing rooms. ‘One of the key decisions was to put the sports hall on the first floor, to ensure that it and the swimming pool could benefit from rooflights, to provide passive heating and daylight, which saves energy and is good for wellbeing,’ says Palmer.

One of the striking giant fans set into the ceiling in the gym. The fans have been designed to generate air movement to reduce the need to drive down the fitness suite air temperature

Flexibility is key to keeping the building’s footprint and embodied energy to a minimum. The swimming pool, for example, has a floating floor, to do away with the need for a learner pool; the squash courts are separated by a moveable partition to enable them to be converted into additional studio space; and the studio spaces incorporate a moveable partition that allow them to flex to accommodate a variety of class sizes and activities. The compact building’s high-performance envelope has been kept deliberately simple to avoid complex junctions and cold bridges.

In addition, the swimming pool envelope has been fortified with additional insulation, to deal with the higher air temperature and humidity in the space. Employing a simple, system-build envelope solution made it easier to build and, Palmer says, gave contractor Wates Construction ‘a fighting chance of delivering on the design airtightness and thermal performance in practice’.

The rooflights in the sports hall and swimming pool are designed to open. They are arranged in strips in the sports hall, strategically positioned between the badminton courts to allow daylight in while minimising the impact of glare on the players.

Max Fordham has eschewed natural ventilation for an innovative cooling and mechanical ventilation solution for the intensively used, 175-station fitness suite. Alongside a conventional fan coil cooling system, a series of large-diameter, high-volume, low-speed horizontal fans have been recessed into the ceiling, like the slowly spinning rotor blades on a series of upturned helicopters. These giant fans have been designed to generate air movement to reduce the need to drive down the fitness suite air temperature. The large fans are supplemented by 13 smaller fans concealed above the ceiling.

The conventional way to deliver comfort to a fitness suite is to lower the air temperature to help people lose heat. Sport England’s guidance, for example, suggests maintaining temperatures as low as 16°C-18°C. But Palmer says this can result in ‘very high energy use’ that often ‘fails to deliver occupant comfort’ because, when we are sedentary, radiation is the primary mechanism of heat exchange. As exercise intensity increases, however, convection and, eventually, the evaporation of sweat become the dominant modes of user heat loss. ‘If the air in a gym is cool, still and humid, your sweat is unable to evaporate to cool you down,’ Palmer explains.

For those undertaking high-intensity exercise, convective and evaporative transfer of body heat are increased significantly by air movement. ‘By creating air movement and controlling humidity, we are able to achieve much better levels of comfort at temperatures that are not as cold,’ Palmer adds. See ‘Fit for purpose’, CIBSE Journal October 2018 for more on this bit.ly/CJRav.

In addition to the giant fans, four-pipe fan coil units (FCUs) have been tucked out of sight above the suite’s slatted wood ceiling. The FCUs provide the space with heating and mechanical cooling. ‘The client was a bit nervous about the effectiveness of our giant fan solution, so the fan coil units have been sized to cool the space conventionally without the need to run the fans,’ says Palmer, who adds that the client need not have worried. ‘Everyone loves this solution: it’s striking to look at and it’s proven to be very effective.’

In addition to ensuring the university’s management and operations teams have a good understanding of the building and its systems, soft landings enabled the engineers to tweak the fan system once the fitness suite was fully operational. They estimate that increasing air movement in the fitness suite, as opposed to relying on a lower temperature setpoint, will result in a 10% reduction in energy use in peak summer conditions.

Heat for the building is supplied by five ASHPs via a low-temperature buffer vessel. To maximise ASHP efficiency, heating is at 45°C flow/40°C return, which, Palmer says, is ‘quite challenging when we need to heat the pool hall to 30°C. To operate the system at these low temperatures relies on high levels of heat recovery and a high-performance building envelope’. The solution also required non-standard fan coils, air handling unit coils and heat exchangers to exploit the low flow temperatures.

Reducing glare

Plots show the direct sun penetration at two points during the year. These simulations are conducted using a bespoke tool, Beam Tracer, created by Max Fordham to calculate specular reflections. Orange represents the direct sun transmitted through the glazing; pink is the reflection from the pool surface. As a result of the steep-angle reflections from direct sun through the top, lights remain at high level and do not enter the occupied zone, where they can cause glare. At low sun angles, some direct sun penetrates into the pool area and can cause glare to occupants. By carefully mapping the path of the sun, lifeguards can be positioned to avoid areas that experience glare from direct sun.

The ASHPs incorporate load-shedding controls to minimise peak heat loads and reduce their size, capital cost and embodied energy. Palmer says minimising heat loads, maximising heat recovery and using load shedding ‘has allowed us to squeeze the combined capacity of the heat pumps down to 525kW, around a quarter the capacity of boilers in a typical leisure centre’. This ensured the heat pump solution was space-efficient and economically viable.

The pool water heat exchanger, for example, has a heat demand of 500kW, which, under the usual control regime, would take up the full heat capacity of the ASHPs, leaving nothing for space and water heating. However, Palmer says the only time it needs to deliver this output is when it is heating the pool water up from cold.

For the majority of the time, the heat exchanger is only required to output about 50kW to maintain the water at a steady temperature – and because the pool water acts like a huge thermal battery, the system can wait until the demand for heat is lower. ‘We put a lot of work into ensuring the heat pumps are not oversized, because it would have been easy to think we needed four times as many heat pumps. But if you are in control of where the heat is going, it allows you to shed some of the loads,’ Palmer explains.

Two additional water source heat pumps are used to raise the water temperature from 45°C to 60°C to supply the hot water calorifiers.

In addition to the five heat pumps dedicated to heating, the sports centre has five, four-pipe heat pump chillers optimised to provide cooling, but which can also provide free heat to the building. These supply the FCUs with chilled water at 6°C/12°C. The units can simultaneously top up the thermal store using heat reclaimed from the cooling side. The heat generated by activity in the fitness suite and dance studios is captured and used to keep the pool warm and preheat hot water for the showers, explains Palmer. 

There is a heat recovery unit on the pool water filter backwash system, too. The backwash is used to clean the water filters. In addition, to maintain pool water quality, 30 litres of water is added to the pool per bather, with a corresponding amount removed. This water is used to flush the centre’s toilets.

Engineering the sports centre’s low-energy design was ‘the easy bit’, says Palmer, who adds that it is often the execution, rather than the design, that prevents schemes from achieving predicted energy performance. For Ravelin, Max Fordham was novated to Wates Construction under the two-stage design and build contract, and appointed by Wates Building Services to develop its installation and record drawings in Revit. The engineer also worked with Wates’ offsite manufacturer, Prism, to integrate prefabricated service modules and plant skids. ‘It meant we were able to take responsibility for the design from concept to installation,’ says Palmer.

Max Fordham also produced drawings for the client, with all CoBie asset information, as a full BIM project. Palmer is complimentary about how Wates Building Services (now SES) tackled the project. A two-stage procurement route ensured the contractor was able to price ‘every bit of kit specified, to avoid compromises with lower-efficiency alternatives’. Execution was also helped by the soft landings specification insisting that Wates appoint an independent commissioning manager (Banyards). Its task was no doubt helped by the building having more than 200 electricity and heat meters. ‘At completion, the building was properly and fully commissioned so that it performed well from the get-go,’ says Palmer.

Post-occupancy, the soft landings initiative requires Max Fordham to monitor the building and report each month on how the various spaces are performing – a task aided by the engineer having remote access to the BMS and meters.

There were also monthly meetings to gather client feedback. Palmer says: ‘If something was not working, it was raised at the meeting so that, by the next meeting, it had been resolved, which helped ensure the client never lost faith in the design and remained engaged in the low-energy strategy.’

A major challenge with sports buildings is the huge variation in occupancy throughout the day. In the evening, they are usually full and everything is running flat out, whereas, in the middle of the day, they are relatively empty. ‘M&E designs often only focus on meeting peak conditions and do not consider the other times when occupancy drops off,’ explains Palmer. ‘But you have some pretty powerful kit in this building, so you will waste a lot of energy if you don’t turn things down or off when occupancy drops.’

One issue raised post-occupancy was the level of local control that users should be given, particularly over the temperature of the fitness studios after complaints that these were either too hot or too cold.

Post-occupancy evaluation monitoring showed the rooms were performing as designed, with temperatures being maintained at 18°C, and CO₂ levels rising and falling, and the fresh air fans responding accordingly, depending on occupancy. After questioning users throughout the day, however, it became clear that when the spaces were used for high-intensity exercise classes, users found them to be too hot, whereas when they were used for a zen yoga class, for example, users were too cold. ‘We’ve now added a button to each studio to allow the temperature to be changed up or down a couple of degrees for an hour,’ says Palmer.

This approach has clearly worked, and highlights the benefits of a soft landings approach. Perhaps more impressive is that the scheme improved significantly on the original, challenging EUI target of 218kWh·m^-2 per year. 

The post Keeping fit with less energy: Ravelin Sports Centre appeared first on CIBSE Journal.

With the industry reducing operational energy in buildings through more energy efficiency measures, tackling embodied carbon is the next big challenge.

CIBSE believes that there is an urgent need for regulation and, in February, it joined forces with other institutions and construction bodies to send a consistent message to UK political leaders.¹

Together with the UKGBC, IStructE, ICE, CIOB, CIC, RIBA, RICS, ACE, UK Architects Declare, and Part Z, the Institution called on party leaders to commit in election manifestos to reducing construction embodied carbon emissions within two years of taking office. By 2028, it wants them to introduce legal limits on upfront embodied carbon emissions for projects with a gross internal area of more than 1,000m² or more than 10 dwellings.

Embodied carbon is the carbon emissions of a building before it becomes operational. It is associated with materials and construction processes throughout the whole life-cycle of a building, including during the manufacture of building materials, their transportation, and the construction process. It also refers to the carbon produced in maintaining the building and, eventually, demolishing it, transporting the waste and recycling it.

Embodied carbon represents 30% of a building’s total carbon on average, the rest being operational carbon. Our efforts to reduce operational carbon could increase the proportion of embodied carbon to 80% of a building’s total carbon over time.

According to Greater London Authority’s Whole Life-Cycle Carbon Assessment guidance, the embodied carbon of building services in new projects is, on average, 25% – and, in retrofits, up to 75%. This is because of complex systems containing multiple components created using intense manufacturing processes. The use of refrigerants, high replacement rates, and a global supply chain also contribute to high embodied emissions.

Understanding the embodied carbon of products and their components is crucial to creating less carbon-intensive products. This information is usually provided in environmental product declarations (EPDs). However, these are available for few products because of the high cost of producing EPDs due to the complexity of MEP equipment.

CIBSE’s TM65 Embodied carbon in building services: a calculation methodology provides a simple way to estimate the embodied carbon of building services equipment where an EPD is not available. It has been adapted for use in Australia and New Zealand, and two further regional addenda are due in 2024 (USA/Canada/Mexico and UAE).

TM65.1 Embodied carbon in building services: residential heating, published in December 2021, provides the embodied carbon for residential heating systems.

TM65.2 Embodied carbon in building services: lighting, published in August 2023, gives lighters a tool to estimate the embodied carbon of lighting products.

CIBSE is set to launch the next in the series – TM65.3 Embodied carbon in building services: logistics – and one covering HVAC in offices is due later this year.

To reduce embodied carbon, engineers should first reduce the need for MEP kit by prioritising passive design options, and avoid overengineering by carefully considering the design and location of systems. Also avoid oversizing by understanding the building requirements (indoor environment, occupant profiles, HVAC demand cycles) and sizing systems accordingly. We tend to size systems for the worst-case scenario, adding further capacity, which leads to oversizing.

Finally, we need to understand the embodied carbon of products, including reusability and recyclability, to help us select the ones with a lower carbon footprint. By minimising the need for MEP equipment, capital and operational costs can be reduced significantly. Reducing dependence on equipment can also increase the resilience of buildings and the built environment to extreme weather.

Decreasing the use of MEP equipment plays a pivotal role in mitigating the carbon footprint of buildings. This aligns with our decarbonisation goals and supports our efforts to reduce our environmental impact.

References:

1. Embodied carbon regulation – alignment of industry policy recommendations, CIBSE February 2024, bit.ly/ECRFeb2024

The post Why embodied carbon must be regulated appeared first on CIBSE Journal.

Apart from proposals for homes created through MCU, the package only addressed new buildings. There are currently no proposals for revising the regulations on works to existing buildings, which means that improvement opportunities continue to be missed when substantial works are carried out.

This adds to the government’s backtracking on minimum Energy Performance Certificate (EPC) ratings in rented properties in late 2023.

The consultation did not address embodied carbon. The Department for Levelling Up, Housing and Communities has been considering regulatory options on this for a couple of years. CIBSE continues to support the Part Z campaign², an industry-proposed amendment to Building Regulations, and the government should come forward with proposals as soon as possible.

Both of these omit huge parts of the building stock’s carbon emissions, on which the Climate Change Committee has urged action.

HEM, the replacement for SAP

The consultation introduces HEM, and HEM:FHS, as a replacement for the Standard Assessment Procedure (SAP). HEM has added functionality and (hopefully) accuracy compared with SAP, but also added complexity and user inputs. A useful change is the distinction between the calculation methodology (= HEM), and the set assumptions and inputs to the calculation (= the FHS ‘wrapper’ – for example, the number of occupants and their activities). This paves the way for other useful applications – for example, wrappers for EPCs.

HEM could also be used outside of compliance calculations, with completely flexible inputs that would allow for the modelling of a home with its specific characteristics, such as number of occupants, heating patterns, and so on. 

Positive moves

There are a few positive elements in the FHS/FBS package: a clear move away from fossil fuels for heating and hot water in new domestic and non-domestic buildings, and more attention to post-completion testing. The latter should be welcome, even if the proposals are somewhat vague. CIBSE recommends examining the feasibility of a rating scale, based on tested performance, that could be used across the stock and support householders’ decisions for rental, purchase and retrofit, rather than for new-build homes only.

Another positive move is more requirements on homes created by MCU, including energy and carbon, airtightness testing, and Part O. This is welcome to protect householders, as homes created through permitted development rights are often sub-standard.

In large part, however, the proposals lack ambition and are a missed opportunity to create buildings that will deliver low energy use and good indoor environments, and not need future retrofits.

FHS and FBS

CIBSE repeated a number of comments made in previous consultations and supported by others, including LETI, RIBA and the Good Homes Alliance.

There is a need to review the approach to metrics and targets, to drive improvements and better relate to measurable, in-use performance.

Fabric and ventilation requirements should be more ambitious to deliver low space-heating demand and better air quality. The proposals for fabric in new-build homes were the least ambitious of the Future Homes Hub options, and less ambitious than in the 2021 consultation, despite 84% of respondents at the time recommending more ambition. 

The requirements for an ‘energy forecast’ for non-domestic buildings of more than 1,000m² can be met by methods that are not intended or suitable for it. This risks confusing designers and building owners, leading to work of little or no additional value being created. These forecasts should require energy performance modelling (for example, Passive House Planning Package, Nabers, or other methods in line with CIBSE TM54).

The FBS consultation acknowledged industry concerns about the National Calculation Methodology (NCM), including its tendency to underestimate space-heating demand (see the CIBSE-LETI response to the 2022 call for evidence³). However, the proposed changes seem very limited and insufficient.

A substantial review of the NCM should be carried out, so that the NCM better supports the implementation of energy efficiency measures in new and existing buildings.

Heat networks

The proposals came alongside the Heat Zoning consultation. CIBSE is concerned that the current proposals do not ensure that new-build networks offer a low carbon solution compared with onsite alternatives, or that they will drive the decarbonisation of existing networks. This is for a number of reasons, including the setting of the notional building when connected to a heat network, and the calculation methodology for carbon content of heat from networks.

References:

1. The Future Homes Standard (FHS), Future Buildings Standard (FBS), Part O, and homes created through material change of use (MCU), CIBSE consultation response, bit.ly/CJCIBFHS
2. The Home Energy Model (HEM) CIBSE consultation response, bit.ly/CJCIBSHEM, and Home Energy Model: Future Homes Standard Assessment CIBSE consultation response to its application to the FHS (HEM:FHS), bit.ly/CJCIBHSA
3. NCM Call for Evidence – Joint Submission by CIBSE and LETI
   bit.ly/3Uq8Tp9
4. ‘Zoning in: the new Heat Network Zoning consultation’, CIBSE Journal, April 2023, bit.ly/49ZPMa5
5. Part Z, part-z.uk
6. Consultation on the introduction of a UK carbon border adjustment mechanism, bit.ly/3QezmmX
7. City of London 2040 City Plan and Sustainability Supplementary Planning Guidance, bit.ly/3UkAY11

The post Glaring omissions: CIBSE response to building standards consultations appeared first on CIBSE Journal.

Fortunately, the lighting industry has been working tirelessly to put tools in place to help designers find their way.

We’re now starting to see the influence of TM66: Creating a circular economy in the lighting industry, which establishes an accessible methodology for assessing the circularity of luminaires.

It’s still early days for TM65.2, the lighting addendum to the TM65 Embodied carbon in building services calculation tool, but it’s a toolkit we must embrace as we’re at the cusp of understanding the embodied carbon emissions associated with a light fitting.

Pre-TM66, the lighting industry was pulling away from a linear model of take, make, use and dispose, but recycling had become our safety net, and the circular economy was an aspirational concept. 

At Nulty, we were trying to include environmental and life-cycle analysis research on our specifications. It was progress of sorts, but with everyone starting to create their own metrics, there was no easy way to compare results and make like-for-like comparisons between specifications.

TM66 changed this by giving us CEAM-Make and CEAM-Specify, two metric-driven tools that created a base line from which to compare and appraise luminaires. It enabled us to hold ourselves accountable as a practice.

In April 2023, we embedded the TM66 methodology into our design process and set ourselves a target of achieving a two or above score for 50% of specified luminaires across all projects over six months. Our goal was to establish a minimum threshold and make circularity a non-negotiable attribute in our design specifications.

It’s has been a big learning curve. Projects come with a challenging mix of constraints, so adding circular principles into the mix is not easy, especially as we operate in a time-sensitive industry with demanding project programmes. It takes time to pull in the data. Manufacturers need a few days to respond to TM66 requests and we have to plan ahead to populate our specifications. There’s also work to be done to achieve the depth of detail required. The majority of TM66 scores that we received over the past six months came via the CEAM-Specify triage tool; in some instances, we had to give products a 0 score when manufacturers couldn’t provide the information we asked for. 

All of this shows us that the circular economy is a proposition in its infancy. We need widespread adoption of TM66. Lighting designers can help by advocating the need for data to back up decision-making. It should be our responsibility to encourage manufacturers to adopt TM66, and clients to invest in sustainably viable luminaires by using the data from TM66 to safeguard our specifications. 

Like the rest of the built environment industry, we have a lot to learn about calculating the embodied carbon emissions associated with a light fitting. TM65.2 is relatively uncharted territory for us all, so it’s important that we use this tool to accelerate learning. It establishes a framework for assessing the embodied carbon values in the short term, to give manufacturers the time they need to dig into the seemingly infinite layers of detail around materials, processes and supply chains.

In its current iteration, TM65.2 can give us indicative estimates of embodied carbon emissions, which will help to improve our knowledge on a holistic level and create a context in which more informed decisions can be made. It’s a work in progress, and we’re a long way off the tipping point where we can affect the design process, but TM65.2 can be an educational tool to move things along.

The lighting design industry should also improve its definition of the term net zero. We need to move away from separating embodied and operational carbon when we assess project carbon footprints. We need to widen the scope to consider how that building performs over time, how it’s dismantled, and how it’s repurposed after use.

Whole life carbon calculation is the direction in which we should be pointed – we need to make this term an instinctive way of thinking, as it will make sustainability easier to navigate in the long run. It’s one thing to design a carbon-neutral lighting scheme, but another thing entirely to deliver a carbon-neutral project.

• TM66 and TM65.2 are available at www.cibse.org/knowledge

About the author
Gary Thornton is an associate lighting designer at Nulty

The post Navigating the circular maze: tools to create more sustainable lighting design appeared first on CIBSE Journal.

Without attention, there is a risk that these sites will become stranded assets (buildings that the owners will no longer be allowed to sell or rent). Frequently, it is assumed that once a building management system (BMS) has been installed or upgraded, the site will run efficiently. This is usually not the case, however. 

Often, these systems are not programmed correctly or are adjusted over time and rarely recalibrated as the building evolves. 

As part of the solution to making sure our buildings are fit for purpose five to 10 years down the line, we need to make the building truly smart, using automated continuous control optimisations with regular seasonal recalibration via the BMS. If we do, we can reduce the carbon emissions associated with each building, typically by 20-60%.

This case study covers work done by REsustain with Feldberg Capital on Knollys and Stephenson House, a 17,600m² (net lettable area) office building in Croydon, built in 1967. 

The continuous control optimisations were implemented from 1 October 2022, remotely via a gateway to the BMS. From October 2022 to July 2023, these improvements have provided 28% energy savings, avoided the need to emit 232tCO₂ into the atmosphere, and saved £171,000 in operational energy costs over the nine months (see Figure 1).

The building

This multitenanted building is heated and cooled using the original variable air volume reheat system that has been adjusted over the years. The chiller and cooling towers have been decommissioned, and variable refrigerant flow (VRF) systems have been installed in individual offices to cool them in the summer. The building was using approximately 215kWh/m² (gas and electricity together) each year, which corresponds to emissions of 1,110tCO₂ and an operational energy cost of around £26/m². 

A data gateway was deployed in April 2022, and has been streaming to the REsustain platform since then. To make the most of the polled values and to fully understand the building, a full-calibrated dynamic thermal model of the building was created. This includes principal HVAC specifications and control patterns. The building geometry was modelled in DesignBuilder v7 and then transferred to the EnergyPlus v9.4 calculation engine. 

The internal gains were based on site visit information, and the annual pattern of occupancy, lighting and plug load in the spaces were taken from standard ASHRAE profiles for an office building. The building was assumed to be occupied for eight hours a day, five days a week, except for one floor that was known to be occupied 24 hours a day. The actual tenant-occupancy numbers were also included in the model.

The HVAC system was modelled as is and was matched to utility bills to ensure alignment between assumptions in the model and real-life operation. These details were taken from documentation obtained from site visits. The energy usage was calibrated to the utility data using the international performance measurement and verification protocol methodology, allowing for a maximum 15% error on the root mean square error, as stated in ASHRAE guideline 14-2014 (see Figure 2).

The rules engine then ran through all of the data and identified the following groups to be controlled throughout the year.

1. Ventilation load to be reduced at certain times.
2. Fans to have a stricter schedule to reflect operational times of the building.
3. Eliminate simultaneous heating and cooling.
4. Ensure the boiler plant is operating only when necessary.

The optimisations were implemented in the energy model to forecast the potential energy, carbon and cost savings. It was estimated that the building could potentially save 26% energy usage, £140,000 of annual operational cost, and reduce carbon emissions from 1,110tCO₂ to 900tCO₂ per year – a 210tCO₂ reduction (see Figure 3).

Implementation of controls optimisation

In October 2022, the implementation of the controls’ optimisation began. Because of a milder autumn, the VRFs in the office spaces were able to maintain comfortable temperatures, so the boilers remained turned off for the months of October and November. This meant that only the ventilation control strategy and fan control strategy were implemented in those months. 

This was not straightforward. When trying to implement the strategy it was not possible to move the outdoor air dampers via the BMS because, as a result of their age, they were now stuck. Instead of moving the dampers, the control strategy was applied to the fan. The flowrate was reduced to 30%. It was thought that to reduce the fan to a lower flowrate could cause it to fail, so this was deemed to be the low limit.

The central boilers were turned back on in December 2022. At this point, the simultaneous heating and cooling elimination strategy was implemented. There were reheat coils in the four ducts leading from each air handling unit. The initial plan was to close these. However, it was found that the reheat coil valves had corroded, stuck at their 100% open position, so an alternative was found. 

In this case, a decision was made to turn the hot water temperature setpoint down from 70^oC to 60^oC, with a weekly pasteurisation cycle. It was hoped that the hot water temperature could later be dropped further to 50^oC. It was also suggested to the facilities manager that variable speed drives be put on the low temperature hot water pumps to allow the circuit to be more controllable. These were not added; instead, the pumps were controlled on a daily/weekly basis to reduce heating energy consumption. 

To understand how much energy is being saved as a result of these optimisations, the calibrated energy model is updated monthly using BMS data, weather data, any changes relating to tenancy or retrofit, and the utility bills. Once this calibration has been verified, the control optimisations in the model are removed and the model is rerun for the previous month, then compared with reality to measure what effect the changes have had.

The optimisation of the services at Knollys and Stephenson House proves that – by making buildings smarter and constantly analysing control patterns – it is possible to make existing building stock considerably more efficient without any significant capital expenditure or the need to add any further embodied carbon into the building. 

About the author
Annie Marston is chief product officer at REsustain

This article is based on a paper presented at the CIBSE Technical Symposium 2023 titled A comparison of forecast energy reduction through control optimisation in an existing building with actual data from the optimised building

The 2024 CIBSE Technical Symposium will be held on 11-12 April 2024, at Cardiff University, Welsh School of Architecture. www.cibse.org/symposium

The post Back in control: making savings with BMS optimisation appeared first on CIBSE Journal.

James said that the key to attracting people into the sector was to tell them how an individual could have a positive impact on the planet by becoming a building services engineer. She told a packed auditorium at the Royal College of Physicians that, in one year’s work as a graduate engineer, she had saved 500,000 Kg of CO₂ emissions.

Undergraduate of the Year Ruairi Devlin

James said that relaying this message to just one undergraduate careers fair had resulted in her recruiting three Cambridge University graduates to her company. ‘We make such a positive impact on communities and the environment, and we need to get this message across,’ she added.

Nine graduate finalists were asked to answer the question, ‘What practical actions would excite teenagers to join the world of building services?’ The awards aim to empower young engineers to put forward their ideas and arguments. From mentoring to real-world engagement and the importance of a sense of purpose, each finalist offered diverse approaches, with unique perspectives on how to excite and engage young minds in building services.

Apprentice of the Year: Level 3-4: Sidney Hargreaves

The live presentations followed an introduction by CIBSE President Adrian Catchpole, who commended the young engineers for taking the opportunity to lead by example, which was the theme of his Presidential address earlier this year. 

‘The finalists exemplify the ethos of taking a lead and steering the trajectory of building services to new heights,’ Catchpole said. 

The Young Engineers Awards were held on 12 October, and were staged at the Royal College of Physicians for the first time. They included the CIBSE Undergraduate of the Year and Apprentice of the Year Awards (see panel, below), as well as the Employer of the Year Awards.

Apprentice of the Year: Level 5-7: Jess Sargent

The Graduate of the Year Award is supported by ASHRAE and CIBSE, and ASHRAE President Ginger Scoggins addressed the audience. She emphasised the exciting, yet challenging times, that lay ahead, and focused on climate change and improving indoor air quality. 

‘The awards recognise the outstanding contributions of young engineers; we need each and every one of you if we are to create a better future,’ she said

Apprentice of the Year: Level 5-7 finalists, from left to right: Owen Sayers, Mitchell Holland, Finley Bowdidge, Lauren McNaughton, James McLarnon, Jess Sergeant

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To answer this question, we need to understand what the younger generation wants from a career and how we can give that to them – and, importantly, we need to make sure they understand that we can give them what they want. So, what do they want?

This generation of teenagers, college students and university graduates want to feel a sense of purpose through their work: to make positive, long-term impacts on community, wider society, and the environment. I’m a graduate engineer working in heat networks, and it’s this sense of purpose that drew me to building services.

A 2022 Gallup survey of 5,800 adults found that 72% of 18 to 29-year-olds feel it is extremely important that their company has a focus on long-term benefits to society instead of short-term profits, a significant increase compared with other age groups.

In 2021, another Gallup survey found that 33% of Generation Z (those born between the mid-1990s and early 2010s) feel it is very important that their job allows them to work for a greater cause, compared with 27% of millennials (those born between the early 1980s and mid-1990s). 

A Deloitte survey in 2019 found that around half of Gen Z and millennials want to make positive impacts on society.

I want to focus on those phrases ‘long-term benefit to society’, ‘work for a greater cause’, and ‘positive impact on community’. This is what teenagers, college students and university graduates want – to feel this sense of purpose. Fortunately, we work in an industry where we don’t have to bend over backwards or pull clever tricks to give the appearance that our work aligns with these goals, because it directly aligns with them.

An obvious example of a long-term benefit to society is the work we do in reducing the carbon emissions from buildings. We work for a greater cause by helping to reduce energy bills during the cost-of-living crisis. We make a positive impact on the community by improving people’s standard of living and comfort in their workspaces and homes. We know this, but teenagers, college students and university graduates don’t.

Graduate of the Year Francesca James, with CIBSE President Adrian Catchpole

So, we know what the incoming workforce wants, and we know how the building services industry can give this to them – but how do we get this message across? 

We need to focus on the individual impact that a person will have if they join the industry, because this is how the sense of purpose is fulfilled.

I know that we all attend careers fairs already, and give careers talks at schools and at universities; we post job adverts on job boards and on our websites; we run internship programmes for teenagers through to graduates; we’re involved in great programmes such as the Stem Ambassadors, where engineers volunteer to run sessions for schoolchildren, teachers and parents – and, obviously, we need to keep doing all of this.

But to really excite the young people we’re talking to, we need to not only highlight the positive impact that the industry has as a whole, but also, critically, we need to highlight the impact that an individual young person can have.

Last year, I gave a careers talk at my university, and I calculated and presented the reduction in carbon emissions that could be attributed to my work during the graduate scheme. This number, to my huge surprise when I actually worked it out, was half a million kg of CO₂. I also gave a case study of a residential development where the retrofit work I designed had reduced residents’ heating bills and improved comfort through reduction in overheating. I was presenting the positive impact that my work had had on real people’s lives in only a year.

After the talk, we saw a huge number of applicants for our summer internship and graduate programmes, and three students who attended the talk went on to be employed by FairHeat. So, practically, in our careers talks, we should be emphasising the reduction in embodied carbon that can be attributed to the work of materials engineers during their graduate scheme.

In our job adverts, we should be giving case studies of sites where residents’ utility bills have been reduced because of efficient lighting design carried out by electrical engineers in perhaps their first year of work. 

And, during our internship programmes, we should be demonstrating the positive impact on the comfort of real people of ventilation design carried out by graduate mechanical engineers.

Young people want to feel this sense of purpose. We work in an industry that directly correlates to these aims, so we can give them what they want. 

Practically, we need to emphasise this relationship in our outreach and recruitment by highlighting the individual impact a person will have – because this, I believe, will excite young people to join this wonderful industry. 

The post ‘Show young people how they can make a difference’: Francesca James, CIBSE Graduate of the Year appeared first on CIBSE Journal.

In June, planning permission was granted by Camden Council for an office redevelopment on the corner of Gray’s Inn Road and Clerkenwell Road, London, for what is believed to be the UK’s largest full-timber, net zero carbon office building.

Building services engineer Max Fordham has used whole life carbon modelling to calculate the embodied and operational carbon of the project. It aims to exceed RIBA 2030 Climate Challenge and Greater London Authority (GLA) planning energy performance targets. 

The designs for the eight-storey project, by architect Piercy & Company, will result in the construction of an 8,826m² (95,000ft²) office building on the site of the former Holborn Town Hall, in central London, for Global Holdings. The eight floors will include contemporary workspaces and a communal rooftop garden and restaurant.

A second 1,115m² (12,000ft²) building – currently known as 88 Gray’s Inn Road ¬ will also be developed on the site, and is expected to include six affordable buildings and a ground-level affordable workspace.

The team aims to outperform the UK Green Building Council’s (UKGBC’s) Net Zero Office target, with the design seeking to lower operational carbon emissions by up to 82% compared with a typical office building. It is also targeting a Nabers UK 5.5* energy rating for the main building. 

One of the headline-grabbing aspects of the development is the main building’s full-timber structure. This will result in a much lower embodied carbon compared with a typical office building using concrete or similar materials, explains Max Fordham’s Edmund Chan, principal engineer and lead project engineer for the 100 Gray’s Inn Road project.

‘Everything in terms of superstructure will be timber, made from highly sustainable glue-laminated (glulam) timber beams and cross-laminated timber slabs as part of the overall design,’ Chan adds.

Embodied carbon in future refits has influenced design

According to Andy Heyne, director at project structural engineers Heyne Tillett Steel, the timber structure, combined with its high-performance façade, should outperform the UKGBC’s Building the case for net zero office baseline target by more than 50%. ‘With more than 2,400 tonnes CO_2e stored within the timber, the structure is effectively carbon negative during its lifetime,’ he says. 

The reinforced-concrete basement walls of the existing buildings will be repurposed for the development. ‘While the basement will be dug deeper [for the new building], we are reusing the foundation on the perimeter. We will be using as much as possible down at that substructure level,’ says Chan. 

The Max Fordham team has gone through a process of identifying, assessing and pre-auditing the existing buildings in terms of soft-strip and deconstruction of building elements. ‘There is a lot of material that can be reused from soft-strip, such as raised access floors, lighting and MEP strip-out material,’ says Chan. 

Delivering performance

Ensuring the materials selected for the building are as suitable as possible for future deconstruction and reuse is also key. ‘Our retained role is to be part of that strategic approach moving forward, using expertise in these areas and working with the contractor and their supply and delivery chains to make that happen,’ says Chan.

In terms of operational carbon, the building will use 100% renewable grid electricity, rooftop photovoltaic panels, an all-electric heating, hot water and cooling system, and demand-driven displacement ventilation for the office floors. 

‘This is one of our first large office projects that went through the updated GLA set of requirements for sustainability and energy efficiency, which includes whole life carbon and circular economy statements,’ says Max Fordham’s principal sustainability consultant and partner, Henry Pelly. Knowledge from the firm’s first Nabers UK 5.5-star project at 11 Belgrave Road (see ‘Ratings winner’, CIBSE Journal, February 2023) was fed into 100 Gray’s Inn Road. 

A key challenge in such a project is to ensure that lifetime embodied carbon calculations are realised. Avoiding compromises that might change aspects of the design – which could impact energy performance and, therefore, embodied carbon – is crucial, says Pelly. 

‘One of the things about embodied carbon is that everything comes as a package and it all fits together,’ he adds. ‘It’s not like you can just pull out one element because everything’s been designed to work together. The timber structure, for example, is prefabricated off site and assembled on site, reducing carbon inputs.’

There are 2,400 tonnes CO2e stored within the scheme’s structural timber

Max Fordham’s approach to embodied carbon and energy performance modelling is to be conservative about potential savings rather than assuming best-case estimates. ‘It is quite helpful to adopt a kind of “worst case” embodied carbon modelling approach so that, at every stage of the process, there are opportunities for improvements,’ Pelly explains. ‘Instead of taking potential opportunities for savings early on in the process – for instance, the raised access floors we are reusing – we don’t assume them for the modelling until they are written into the documents and we know they are definitely going to happen.’ 

This is important to avoid overestimating savings, Pelly adds, and focus on where improvements can be made to the building.  

Similarly, while estimating the carbon impact of future deconstruction at end of life is a challenge, the team’s model includes only what is technically possible now, rather than assuming the potential impact of future technologies. 

The design decisions reflect potential reconfigurations in the future and the consequent embodied whole life carbon impact. For example, the team looked to minimise ductwork by having more air handling units (AHUs) at each floor level, rather than having multiple vertical ducts running from one centralised AHU.

Enabling works on the project are expected to start imminently, with work starting on site in early 2024. Completion is anticipated for the first quarter of 2026.

Responsibility for keeping to embodied carbon budgets will be held by each of the parties under contractual arrangements for individual packages of work, says Chan. ‘For example, in the concrete work package, they may be able to choose to use lower carbon solutions in different parts of the construction sequence, but they can’t pass down any carbon budget “overspend” to the next contractor to make up somewhere down the line.’

Ultimately, achieving net zero carbon requires a ‘whole building’ approach to design, adds Chan. ‘We’ve driven down the building’s operational energy demands by prioritising passive principles and optimising the façade, engineering efficient active systems, and supplementing through low and zero carbon energy sources.’ 

Max Fordham is committed to having the in-use performance realised and verified by others. ‘We want to show that low energy design is not a concept, but a reality in our lifetime,’ he says.

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