OBJECTIVE v3

Description

OBJECTIVE v3 (formerly known as TEUI3) is the latest open source Building Code Review, Targeting and TEUI measurement tool developed by the Ontario Association of Architects and now the OpenBuilding project under a public sponsorship grant.

New Features in 3.036: Compare Embodied vs. Operational in the ‘Carbon Impacts’ worksheet, Related Sankey Tool that reads the Excel File, Completed/Corrected Energy Balance in Cooling, New IPCC AR6/Paris Agreement Aligned Lifetime Carbon Targeting Methodology. Improved DHW/SHW Water Methods. Re-organized for Machine-reading & Machine-Learning study optimizations. Arctic Solar Gains Factors and Fuel added (Oil for Space Heat and DHW is an option now).

OBJECTIVE v3 launched in Q4 of 2024 as an excel-based spreadsheet (an Apple Numbers and a LibreOffice xml versions will soon be included), with a case-study document (PENDING) that features some of the buildings that helped to calibrate the tool to try to align Reference (NBC/NECB/OBC) models with the Targeted (Design) and Actual (Utility Bills) performance metrics, with specific user-guidance on how to work with some of the variables to understand their respective roles and impacts, such as the net-useable gains function or gains n-factor.

TEDI plays an important role in OBJECTIVE, as it has been adopted as a metric by the international Passive House standard, as well as many other municipal, regional and national standards, but its use at the design stage requires numerous assumptions, such as occupancy and occupant load, the usefulness of internal gains from occupants and the related schedules of occupancy (time*intensity), and the actual useful internal gains for all additional gains such as solar gains, and gains from plug loads and equipment and the ability of mechanical components to recover this energy and/or absorb it in the building itself (thermal mass, capacitance, etc.). In particular the question of when and where gains occur, and whether they are in fact needed at that time, is what is meant by their ‘usefulness‘. A solar gain of 1,500kWh in October cannot be used to offset a thermal demand need of 1,500kWh in January, but often this is how total gains versus total demand is considered in all but dynamic, hourly energy modelling tools. Any over-estimation of the usefulness of internal gains can have the effect of lowering forecastedTEDI (which can help you meet a standard), at the risk of cooling season building overheating (which can help you make occupants very uncomfortable!).

TEDI also integrates envelope-air leakage and ventilation, which further muddies the metric. We have written an article and built a separate Ventilation Calculator just to study the outsized influence of ventilation rates on TEDI, and where we make the case, as prompted by Dr. Ted Kesik, to separate out Ventilation from the TEDI metric so that TEDI becomes a pure envelope-rating metric that can aid in understanding a building’s thermal resilience and also to limit trading-off envelope efficiency with mechanical recovery efficiency, which can actually reduce a building’s thermal resiliency (think of a power blackout during a heatwave). OBJECTIVE shows both options, TEDI with, and TEDI without Ventilation included.

When PHPP assumes a minimum hygienic ventilation rate of 8.33l/s/pp, or 3m3/hr, the first question we asked is, after the Covid19 pandemic, is this ventilation rate adequate, and does it align with ASHRAE and Building Codes in North America for a given occupancy? Based on Dr. Joseph Allen’s research at Harvard, 8.33l/s/pp is deemed inadequate, and a substantial body of research has shown that 12-15l/s/pp should be the ventilation target rate going forward. Increasing ventilation to these new rates could cause many already certified Passive House projects to fail to meet the PHPP defined heating season TEDI value of 15kWh/m2/yr, in order to supply an appropriate amount of fresh air, and to keep indoor CO2 below the Health Canada guideline of 1,000ppm. OBJECTIVE v3 now allows three methods of ventilation calculation, 1) as a function of volume and air changes, 2) as a function of occupants and a ventilation rate (constant ventilation) and 3) as a function of occupant-based ventilation rates tied to a schedule of occupancy (most efficient).

Because of the complex issues surrounding the usefulness of gains, and because of the large influence of ventilation loads on TEDI, this is why we feel that the TEUI metric should always be the primary consideration of building performance, as it is absolute, measurable and easily audited from utility bills and it defines both the total energy and total operational carbon of a project. It also forms the baseline to equate an equal amount of locally-produced energy required to claim the title of an operational Net Zero Building, where Energy Produced = Energy Consumed.

OBJECTIVE v3 now bridges the gap between Early Stage design programs and the EUI targets of proprietary standards and emergent targets in Provincial and National Building Codes such as the Step Code in British Columbia, and the Tiers in NECB and NBC2020 and the forthcoming NECB and NBC2025, as well as municipal green standards such as the Toronto Green Standard. TEUIv3 offers architects and engineers an accessible, free tool that can form the basis of an enhanced design collaboration, where envelope, building geometry, occupant loads and schedules and a host of other metrics are carefully defined at the outset to arrive at optimal building performance well before the traditional handoff point at the Coordination phase. It also helps challenge many of the built-in assumptions with energy modelling schemes, from schedules, to useful gains, ventilation rates, shading systems and helps an architect to develop strategies for all of these functions in order to refine and optimize the building from the earliest phases of design.

Note: OBJECTIVE is a FREE tool at https://objective.openbuilding.ca – the cost for the excel version of the app here is considered a donation for OpenBuilding to continue to maintain and develop these spreadsheet workflows for user convenience and to cover the fixed costs we face as a nonprofit in a cruel hard word with never-ending expenses.