GBC About Calculator
- The GBE Green Building Calculator ‘GBE GBC’ provides a low-cost Energy Performance and Cost analysis tool for new building designs, for those not engaging in PHPP planning tool, or SAP, SBEM, IES, etc. calculations.
- This Microsoft Excel calculator was originally developed to permit Post Graduate Architecture students to analyse their own studio building projects.
- Brian Murphy, Founder of Green Building Encyclopaedia (GBE) https://greenbuildingencyclopaedia.uk created the spreadsheet and he has continued to update and expand it.
- The consistent results meant that different building shapes, methods of construction, materials choices and resultant energy demand and consumption could be easily compared.
- My part-time students all took the file to their offices and started applying them to their live projects.
For a Future:
- With XR Extinction Rebellion, Greta Thunberg’s behaviour change campaign, Architects Declare, ACAN and many other groups and Government bodies declaring and becoming involved in environmental design in a bigger way, we have a chance to engage designers in more scrutiny of what they design.
- So GBE have restarted development of a calculator that can be useful to enable many more to engage more robustly in meeting new targets as they become commonplace.
- Moreover they will be able to understand why 50 mm of stone wool insulation, shown in the aging textbooks, is no longer enough, do their own U value calculation independently of manufacturers who will do them for free, if users pay for their insulation. (Whether it is appropriate or competent in that location in the construction)
- GBE has developed this as an MS Excel calculator (so far) for a number of reasons:
- Its open-book, not a black box, no hidden pages, all cells accessible to interrogate the calculations
- It allows for user access, interrogation, greater understanding and learning opportunities.
- Many will already have and may be familiar with (MS Excel) which enables a larger audience of users a quick way into building analysis.
- It also allows users to customise, manipulate and develop bespoke versions for the user’s organisation
- GBE will maintain a stakeholder group to encourage customisation to be shared to be considered for development into the core file for the greater good.
- Having a large number of users some customising may help with feedback loops developing the Calculator with more features and stronger datasets
- Other options considered but not adopted yet include Database, if data and version upkeep needs to be delivered and controlled more robustly we will consider this.
- As a nod to QA procedures all actions are date stamped, and actions recorded in a revision table, if multiple developers become involved then initials will be added against actions.
Scope at GBE launch:
- Whole Building and Room by Rooms Schedule of Accommodation, areas and volumes, hours of operation, design temperatures, inside and out
- Room by room heat loss calculator to determine radiator or underfloor heating requirements
- Analysis of Form Factor and optimal U values to respond to them
- Elements and secondary-elements are selected from ready-made lists to match the project, their dimensions added by user and their areas are automatically calculated.
- Since windows and doors come in a multitude of sized then a schedules allows their incorporation
- Allows users to compare and choose between Building Regulations Part L, LETI, AECB CarbonLite, Passivhaus, EnerPHit, EAMs, etc. including: U values, Airtightness, Form factors, Elevation window %.
- Automatically see what thickness of different k value insulation materials is needed to meet U values
- Allows the user to populate and assemble elements by choosing their combination of functional components and then choosing the materials for each component.
- Costs of insulation and windows are added here to help persuade architects and clients to spend money on insulation and higher performance windows and glazing
- Allows Architects to cost plan their projects with a Bill of materials, quantities, labour and costs based on building fabric only so far. (Non-external envelope elements and services to be developed)
- Started building a dataset of materials and products with performance and costs to add to and populate the calculator (Supplier and manufacturer collaboration needed to populate these further)
- Element Summary to compare calculated U values with selected or target U values
- Calculates energy losses from each element and secondary-elements to give total losses or demands
- Calculates each element and secondary elements total demands as a % of the whole
- Allows comparisons to be made by the user to prompt reconsideration of earlier decisions
- To spend more money on insulation or better windows to reduce running costs
COVID-19 Lockdown Development
- Due to the weekly time pressures during the initial creation the content was restricted.
- Many of the original ambitions remained in separate calculators
- So the plan is to continue development if demand shows it is useful or required
- An Architect Client of GBE asked for a Retrofit Calculator for Victorian Terrace this has been started by adding more elements.
- During Coronavirus Lockdown in between Lockdown Learning On-line CPD the opportunity arose to continue with this calculator’s development.
- Additions to developed:
- Refurbishment Elemental Assemblies (started)
- Embodied Energy, Embodied Carbon, Sequestered Carbon (merging in existent GBE Calculator)
- Secondary Element Calculators: (Frame %, Ug, Uf, Uw, U values, G Values, datasets) (started)
- Decrement Delay (using existent equation and data sets) (started)
- Condensation Check (using existing dataset)
- Product Datasets: k or U values, Thicknesses, Insulation, Glazing, Building fabric (started)
- Cost planning: adding non-envelop elements and services to existing building fabric calculations
- 892 readymade competent elemental assemblies (Using existing mothballed GreenSpecStudio datasets)
- Create date: 25/03/2018
- Last edited date: 30/10/2020
© GBE GBC GBL NGS ASWS Brian Murphy aka BrianSpecMan **
31st October 2020