ADAPTING TO PART L REGULATION CHANGES

Transcription

1 ADAPTING TO PART L REGULATION CHANGES Discover how to efficiently respond to the UK government s building regulation changes. We use the Part L regulation in this paper as an example of how regulation can be met by using performance based design. The principle is equally applicable for any other building performance regulation. Copyright 2013 Sefaira Ltd.

2 2 Why Architects Need Performance Based Design to Achieve Regulatory Requirements The UK s Part L building regulation focuses on the conservation of fuel & power with an aim to improve energy efficiency and cut greenhouse gas emissions from new and existing buildings. It achieves this by specifying the minimum efficiency and performance of the building fabric and heating and cooling systems, in order to ensure thermal standards. This paper reviews how architects currently meet this regulation, proposes a radical but necessary change in approach and illustrates how it can be effectively achieved using two example projects. The Part L regulation is directly aligned with the European Union s Energy Performance of Buildings Directive (EPBD). First published in 2002 to reduce energy consumption and waste, the EPBD requires enhanced building regulations and energy certification schemes across all EU countries. The recent changes to the Part L building regulations will come into effect on April 6th, 2014 with the overarching goal of reaching Zero Energy for homes by 2016 and Nearly Zero- Energy for non-domestic buildings by The scope of Part L does not change but the performance requirements for compliance become much tougher as the government strives to reach its 2020 goals. The changes raise the threshold requirements for high performance and efficient building systems within new homes and non-domestic : they are to achieve a 6% & 9% reduction in carbon emissions over 2010 levels respectively. The new Part L also introduces a minimum Fabric Energy Efficiency (FEE.) The 2013 changes mark the fifth amendment to Part L since the year With targets set for Nearly Zero Energy buildings by 2020 and the larger goal of Zero Energy Buildings soon after, it is safe to assume that the government will have to implement more rigorous changes soon. Considering that the latest ammendments will not be as stringent as initially proposed (they overlook retrofit projects which account for a large percentage of the UK s building stock), further revisions will be inevitable if the government is to make a significant dent in the UK s CO 2 Emissions. In order to meet these requirements, architects will need to integrate performance based design much earlier in the design process than they currently do. In the next two pages, we illustrate how architects currently work and how performance based design can help improve the process. COPYRIGHT 2013 SEFAIRA LTD. ADAPTING TO REGULATION CHANGES

3 How Architects Currently Meet These Goals The diagram below illustrates the process through which architects currently obtain Part L compliance. Using tools that focus on validation, not analysis, a lot of architects submit their designs for Standard Assessment Procedure (SAP) calculations without already having a good understanding of their performance or any certainty of whether a design will pass or fail. If it does fail, the designer still doesn t learn what he needs to improve to make it pass. He will likely submit the next version, again without knowing whether it will pass. As a result, the design process is more tactical than strategic and in many cases, last minute fixes and design compromises are used to get approval. 1 Design 2a Pass 3 Comply Part L Design Variables SAP Calculation Part L Compliance THERMAL ENVELOPE SYSTEM TYPES SYSTEM EFFICIENCY LIGHTING EFFICIENCY LOW OR ZERO CARBON TECHNOLOGY (LZC) BUILDING EMISSION RATE BELOW TARGET EMISSION RATE 2b Fail SAP Calculation BUILDING EMISSION RATE ABOVE TARGET EMISSION RATE CERTIFICATION 2014 changes mean tougher benchmarks & multiple iterations Fig 1: How the compliance process currently works The tighter requirements in 2014 will make the path to obtaining permission more difficult. In order for architects to adjust effectively, it will be necessary to already carry out analysis during the design process to submit schemes for validation when their performance levels are already known.

4 4 How Performance Requirements Can Be Met More Easily 1 Design using Sefaira Part L Design Variables 2 Pass SAP Calculation 3 Comply Part L Compliance THERMAL ENVELOPE SYSTEM TYPES SYSTEM EFFICIENCY LIGHTING EFFICIENCY LOW OR ZERO CARBON TECHNOLOGY (LZC) BUILDING EMISSION RATE BELOW TARGET EMISSION RATE CERTIFICATION Multiple iterations optimise variables Fig 2: How the compliance process could work with Sefaira To make compliance easier, designers need to consider performance from Day 1 of their design process. They need tools that are designed specifically for this purpose and allow analysis with very few inputs. When using Sefaira, designers need only three parameters- a basic envelope model, a location and an overall idea of the building program - to design Part L strategies from the begining of their creative process. Sefaira shows Part L baselines as part of the Sefaira for Sketchup interface, which makes it easier for designers to immediately know whether their early stage design will meet requirements. By designing with Sefaira, they can holistically test several iterations of their design in order to optimise and understand their concept before submitting it for SAP calculations. Instead of only validating their design in the later stages of the creative process, they can use real-time analysis to shape their schemes. Sefaira also allows architects to show a documented analysis of high efficiency alternative systems -- a requirement of Part L -- and export clear ready-to-use reports that can be submitted to show that the technical, environmental and economic feasibility of all systems have been tested. Using two scenarios, we illustrate how Sefaira can drive sustainability in response to regulatory demands. COPYRIGHT 2013 SEFAIRA LTD. ADAPTING TO REGULATION CHANGES

5 Scenario 1: New Build In this example, we carry out performance analysis on a government funded new build project which already meets 2010 Part L requirements. Our ensemble is made up of a city hall, concert hall and theatre, in East London. In order to comply with 2014 regulations, our design needs to be adjusted to achieve a 9% reduction compared to 2010 acceptable carbon emissions. We will test scenarios with different envelope options, HVAC systems & efficiencies, as well as low carbon technologies, such as solar PVs, to see which single and combined variables help us reach our goal. Fig 3: Our proposed scheme Baseline Concept To reach a 9% reduction, our annual CO 2 production needs to fall from 1,398, 901 kgco2 to a value below 1, 272, 999 kgco 2.

6 6 Fig 4: Baseline calculation showing CO 2, Energy Consumption, Space Cooling & Heating rates. These outputs were selected as they directly relate to the conservation of energy. A first round of analysis reveals that our building is susceptible to high solar gain and that it loses heat through ventilation and conduction. Heat gains in summer months Heat loss culprits Fig 5 & 6: A great proportion of our heat loss is through the ventilation system and conduction through the building fabric. With this knowledge, we are now able to make relevant adjustments to the design to improve its performance at an early stage. In this instance, we ll focus on the fabric, glazing, solar shading and HVAC system efficiency. Improving Design Performance Our next step is to test single improvement strategies to see what impact they have on the design. COPYRIGHT 2013 SEFAIRA LTD. ADAPTING TO REGULATION CHANGES

7 Strategy 1. Figure 7 shows that specifying more efficient fabric properties such as the facade and roof glazing U Factors, the solar heat gain coefficient, the wall U Factor, air leakage, and surface reflectance gets us a 5% reduction. Strategy 2. Glazing Ratio & Solar Shading adjustments offers approximately 1% savings in carbon emissions. Strategy 3. Adding a Mechanical Ventilation Heat Recovery System that operates at 70% efficiency contributes a 9% saving to the baseline. Fig 7: Some of the changes we made to the builidng fabric. It is safe to assume that adjusting the glazing ratio and applying solar shading are the two strategies that have the least impact on our design. Adding an Mechanical Ventilation Heat Recovery System appears to be a crucial strategy; it offers a 9% reduction in carbon emissions- significant enough to make it a stand-alone measure. 1 Strategies 2 3 Fig 8: The selected strategies showing improvement in places and worsening performance in others. Combining Strategies It is essential to check the combined effect of different strategies as you cannot always expect an additive outcome. In this example, we tested several combinations. The most rewarding bundle is a fabric, glazing and shading upgrade as well as the addition of a MVHR system. A combined 13% reduction in Annual CO 2 Production goes well and beyond the 2014 requirements for meeting Part L.

8 8 Strategies Bundles Fig 9: Results for single and combined interventions do not always impact the design s performance in an additive way. Scenario 2: Retrofit A majority of 2050 s building stock has already been built according to a United Nations Environment Programme estimate. From a Lifecycle Approach, 80% of greenhouse gas emissions occur during the period of building use. In order to significantly lower carbon emissions, it is clear that retrofits will have to play a crucial role. Considering the long lifespan of buildings, it is important for designers to bear 2050 targets in mind already, so that investments and upgrades made now remain beneficial and relevant in the long run. The 2014 UK Part L regulations require a 9% reduction in CO 2 emissions from new nondomestic projects. If this is expected within 4 years for new builds, we can assume that within the next 10 years, retrofits would realistically have to achieve around 20% reductions, and above. Our next example is of a potential retrofit project to be carried out in Our goal is to ensure our retrofit strategies remain relevant to any potential future carbon targets within the next 10 years. If we are to hit our national carbon reduction target of 80% by 2050, almost every building in the country will need a low energy makeover. That means we have to improve nearly one building every minute, and we have to get the interventions right, first time. That is a challenge. The Retrofit Challenge: Delivering Low Carbon Buildings. The Centre for Low Carbon Futures COPYRIGHT 2013 SEFAIRA LTD. ADAPTING TO REGULATION CHANGES

9 Fig 10: Perspective view showing residences with balconies over retail. Our example building is an existing retail space and residential project in Leyton, East London. The table below shows a baseline concept that meets 2010 Part L regulations. Fig 11: Our Annual Space Heating value is just over three times more than Annual Cooling load. Initial analysis tells us that our building is heating dominated. Looking in more detail at the chart below, we see that heat is lost mainly through conduction and infiltration. Our retrofit could therefore focus on improving our building fabric and air tightness in order to reduce our heating load. Fig 12: Monthly Heat Loss chart showing the two major causes of heat loss.

10 10 The pie chart shows that most of our fabric conduction loss in descending order is through the roof, the glazing and finally the walls. We could also adjust our HVAC system where possible to improve our heating efficiency. In addition, the heat gain chart on the right tells us most gains come from the sun suggesting we could introduce shading where possible in order to reduce our cooling load. However, we will need to size our shading devices properly to make sure that we don t block out beneficial heat gain in the winter. Fig 13: Chart showing what building elements are contributing to conduction losses. Fig 14: Our heat gains are predominantly from the sun, particularly in the summer months. Fabric Improvements One strategy for improving the building s fabric would be to increase the U-Values for the roof and walls. Insulation could be applied to the facade of the building to maintain the existing building floor area. The roof could be insulated internally or replaced with a green roof, improving insulation and also adding to the local ecosystem. Fig 15: Details of our fabric improvements. COPYRIGHT 2013 SEFAIRA LTD. ADAPTING TO REGULATION CHANGES

11 Another strategy would be to switch from a light to a medium core structure with the aim of increasing the building s thermal mass. Exposing thermal mass through the floors can be done by taking away carpets and replacing it with a polished concrete finish. By doing this our floors will store thermal heat, releasing it during cooler times of the day and helping us maintain a more even temperature throughout the day and over seasons. Reducing the building leakage levels give a considerable 12% reduction in CO 2 production. In combination, this strategy offers a 19% reduction in CO 2 levels, a 35% reduction in Energy Consumption as well as a 61% drop in Annual Space Heating. Cooling has increased by 2% considering the building is now much warmer overall. Shading & Glazing Upgrading the facade glazing in addition to horizontal shading contributes 3% to our CO 2 reduction but also reduces Annual Space Heating by 11%. Fig 16: Details of our shading & glazing improvements. Boiler Upgrade By changing the Heating Efficiency of our boiler from 0.7 to 0.9, we gain a CO 2 reduction of 7%, Energy consumption drops by 13% whilst Annual Space Heating reduces by 22%. Fig 17: Details of our boiler improvements.

12 12 A Bundle of All Three Strategies By combining all three strategies, our design benefits from a 23% saving in CO2 production and a 43% reduction in Annual Energy Consumption. The 4% increase in Annual Space Cooling can be attributed to the tighter envelope and as a result, a warmer interior. A staggering 77% saving in Annual Space Heating makes this combination worth investigating further. Armed with Sefaira s building physics analysis tool, it is now possible for designers to rapidly and accurately test and adjust their designs in response to unforeseen regulation, brief or budget changes. Fig 18: Details of all strategy details COPYRIGHT 2013 SEFAIRA LTD. ADAPTING TO REGULATION CHANGES

13 How Sefaira Can Help Sefaira allows you holistically test several iterations of your design in order to optimise it before submitting it for SAP calculations. Whilst other analysis tools focus only on validation in the later stages of the design process, Sefaira offers architects the only real-time analysis tool for early stage design within the architect s design environment. The flexible interface allows you set relevant benchmarks for investigating the optimum thermal envelope, system types and efficiency, lighting efficiency as well as renewable technology for your design. It also enables designers show a documented analysis of high efficiency alternative systems, a requirement of Part L - Export clear, ready-to-use reports that show you ve explored the technical, environmental and economic feasibility of all systems. About Sefaira Sefaira was founded in 2009 with a mission to promote more sustainable buildings by helping the building industry design, build, operate, maintain and transform all facets of the built environment. Our applications are based on deep expertise in combining building physics and computer science, and this unique expertise has enabled us to be the first and only company able to provide true real-time physics based analysis to the global building design community. Visit us online at CONTACT SEFAIRA SEFAIRA (US) +44 (0) (UK) info@sefaira.com FOLLOW SEFAIRA linkedin.com/company/sefaira twitter.com/sefaira