Zero Energy/Carbon Building Reduced Algorithm

Democratising the tools for low energy and low carbon building design.

Last updated: 10th January 2022

Date uploaded:

Approved for use

Innovation Lead: David Coley
Project number: EP/V012053/1

Website:
bath.ac.uk/projects/zebra/


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Summary

Decisions taken in the early design stages of a project dramatically influence its low energy and low carbon performance. Most low energy and low carbon design tools are complex for non-specialists to use, due to the large number of inputs needed and a general lack of guidance throughout the process. The Zero Energy/Carbon Building Reduced Algorithm tool helps non-specialists get to an energy and carbon performance estimate on a draft design in less than an hour.

Innovation type: Energy
Organisation type: Research centre

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Project pioneers

A team from the University of Bath's Department of Architecture & Civil Engineering is looking at innovative new approaches to the early-stage design of buildings, to reduce their environmental impact in construction and operation.

The problem

Decisions taken in the early design stages of a project, such as the shape, orientation, and footprint of a building, and the glazing and materials to be used, dramatically influence its low energy and low carbon performance. Yet many construction professionals aren't aware of the quantitative impact these choices can have or lack the specialist knowledge needed to estimate the energy and carbon outcomes of early-stage designs.
Energy performance and sustainability are typically reviewed towards the end of the design process, by which time it is often too expensive to make fundamental changes. As a consequence smaller revisions get made, contributing less to low energy and low carbon outcomes, which often results in higher operational costs and worse performance for building owners and occupants.

Vision

The Zero Energy/Carbon Building Reduced Algorithm (ZEBRA)is a tool designed to better influence early-stage design decisions that can affect the energy and carbon performance of buildings, without the need for specialist knowledge. As well as providing environmental benefits, buildings with a lower or zero net carbon footprint can reduce stresses placed on energy infrastructure, improve running costs for building owners and residents, and provide a healthier and more comfortable environment for building occupants.

Key Insight

The project team recognised that in order to translate research and energy modelling into practical decision-making tools for non-specialists, simplification and guidance would be needed. They felt an algorithm could help to reduce the number of inputs needed, while a robust educational approach to in-tool guidance could upskill users with no previous experience of low energy and low carbon design.

First step

By collaborating across the disciplines of building design and environmental psychology, the ZEBRA team set about adopting a more user-centred approach. This saw them engaging the construction industry to get a better understanding of the functionality required for truly widespread use.

Barrier

Most commercially available tools to help with the low energy and low carbon design of buildings require a detailed description of the project, which is often not available at the early stages of the design process. They can also be complex to navigate for non-specialists in low carbon and low energy design, due to the large number of inputs needed and a general lack of guidance throughout the process.

Whole life innovation

ZEBRA is an algorithm that powers a series of steps and models that enable better low energy and low carbon decisions to be taken early in the design process. To make this tool available to as many people as possible it has been incorporated into a series of linked spreadsheets that can be downloaded easily, although the algorithm could be used in other tools in the future. These spreadsheets integrate the diverse range of elements that can affect the low energy and low carbon impacts of a building, to quickly produce rough estimates for an early-stage design. Some of the factors considered include the shape, orientation, and footprint of the building; the glazing, materials and insulation to be used; and technologies that could be incorporated such as solar panels, heat pumps and batteries. Thanks to the Zero Energy/Carbon Building Reduced Algorithm, working through these spreadsheets only requires 33 inputs and can take as little as 35 minutes in the first instance. To help non-specialists in low carbon and low energy design make better decisions based on the estimates provided, commentary on how to improve the building design is woven throughout the spreadsheet models. This upskills users to adjust the building design; changing the inputs to see how that affects the overall estimated impacts. The team used a robust pedagogical approach to design this commentary; to ensure the tool enabled a learning journey where users could become more literate in what makes a low-energy and low-carbon building, why that is important, and the first principles to apply to their design. While the tool only requires a draft design to see a first estimation of the energy use and carbon footprint; it also prompts users to be more ambitious with their decisions by exploring whether their design has the potential to be a net zero energy or carbon building. By helping more people understand the importance of early design decisions on the energy performance and sustainability of buildings, ZEBRA can also reduce the need for potentially expensive rework to improve the performance of a building at a later date.

Collaborators

Testing with Environmental Design students and postgraduates at the University of Bath and the construction industry ensured that the ZEBRA tool was user-focused; taking only 35 minutes and 33 inputs to get the first estimate on a draft design. Alongside working with academic partners in environmental psychology, this testing also helped to ensure the step-by-step commentary woven into the tool provides an effective learning journey for non-specialists in low carbon and low energy design.

Other partners engaged are: Commercial - E3, Connolly Wellington, James Grayley Architects, Architecture for London, Mitchell Eley Gould Architects, Kove, Studio Hearth. University Partners - Roorkee Institute of Technology, Maulana Azad National Institute of Technology, Delhi School of Planning and Architecture, Vijayawada School of Planning and Architecture, Chennai School of Architecture and Planning.

  • Architecture for London
  • Chennai School of Architecture and Planning
  • Connolly Wellington
  • Delhi School of Planning and Architecture
  • E3
  • James Grayley Architects
  • Kove
  • Maulana Azad National Institute of Technology
  • Mitchell Eley Gould Architects
  • Roorkee Institute of Technology
  • Studio Hearth
  • Vijayawada School of Planning and Architecture

Lead support

With support from the Transforming Construction Challenge, the Active Building Centre Research Programme (ABC-RP) has established a multi-disciplinary research ecosystem to develop innovative tools and technologies to ensure buildings of all scales contribute to a reduction in carbon emissions and a more sustainable built environment. This enabled the University of Bath team to collaborate with researchers from other partner universities and industry professionals more freely.

Long Term Vision

The Zero Energy/Carbon Building Reduced Algorithm (ZEBRA)is a tool designed to better influence early-stage design decisions that can affect the energy and carbon performance of buildings, without the need for specialist knowledge. It has been released under an open licence so that anyone with a draft design can estimate and improve its embodied and operation carbon emissions. Doing this could help low carbon design practices become more widespread, so that buildings of all scales contribute to a reduction in carbon emissions and a more sustainable built environment.

Human Stories

Testing with Environmental Design students and postgraduates at the University of Bath and the construction industry ensured that the ZEBRA tool was user-focused; taking only 33 inputs to get the first estimate on a draft design. Alongside working with academic partners in environmental psychology, this testing also helped to ensure the step-by-step commentary woven into the tool provides an effective learning journey for non-specialists in low carbon and low energy design.

Powerful Processes

ZEBRA is an algorithm that powers a series of steps and models that enable better low energy and low carbon decisions to be taken early in the design process. It integrates the diverse range of elements that can affect the low energy and low carbon impacts of a building, to quickly produce rough estimates for an early-stage design. Some of the factors considered include the shape, orientation, and footprint of the building; the glazing, materials and insulation to be used; and technologies that could be incorporated such as solar panels, heat pumps and batteries. Thanks to the Zero Energy/Carbon Building Reduced Algorithm (ZEBRA), working through these spreadsheets only requires 33 inputs. As a result, using ZEBRA for the first time takes about 45 minutes, or less than 20 minutes once you are familiar with the tool. To help non-specialists in low carbon and low energy design make better decisions based on the estimates provided, commentary on how to improve the building design is woven throughout the spreadsheet models. This upskills users to adjust the building design; changing the inputs to see how that affects the overall estimated impacts. The team used a robust pedagogical approach to design this commentary; to ensure the tool enabled a learning journey where users could become more literate in what makes a low-energy and low-carbon building, why that is important, and the first principles to apply to their design.

Fascinating Facts

Decisions taken in the early design stages of a project, such as the shape, orientation, and footprint of a building, and the glazing and materials to be used, dramatically influence low energy and low carbon performance. Most commercially available tools to help with the low energy and low carbon design of buildings require a detailed description of the project, which is often not available at the early stages of the design process. They can also be complex to navigate for non-specialists in low carbon and low energy design, due to the large number of inputs needed and a general lack of guidance throughout the process. By adopting a more user-centred approach the ZEBRA team has created a tool that only requires 33 inputs. The commentary incorporated in each step can guide a non-specialist to the first estimate on a draft design in 45 minutes or less.

Benefits

Active Energy
To benefit from active energy systems, where buildings are able to generate energy to either become self-sufficient or to trade it with other buildings, projects need to be designed so that their energy generation or storage is greater than their energy needs, at least for a time. This is easier where low energy performance, energy generation or storage is designed-in from the outset.

Emissions
The Zero Energy/Carbon Building Reduced Algorithm (ZEBRA)is a tool designed to better influence early-stage design decisions that can affect the energy and carbon performance of buildings, without the need for specialist knowledge. By enabling anyone with a draft design to estimate and improve its embodied and operation carbon emissions, ZEBRA could help low carbon design practices become more widespread, so that buildings of all scales contribute to a reduction in carbon emissions and a more sustainable built environment.

Time
Most commercially available tools to help with the low energy and low carbon design of buildings are complex for non-specialists to navigate, due to the large number of inputs needed and a general lack of guidance throughout the process. As a result using them to complete a model could take hours or even days.
By adopting a more user-centred approach, including testing with Environmental Design students and postgraduates at the University of Bath and the construction industry, the ZEBRA team has created a tool where a non-specialist can get the first estimate on a draft design in as little as 35 minutes.

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