黑料福利网

In the early stages of building design, selecting the dominant construction type (e.g., concrete, steel, or timber) is one of the most consequential and least reversible decisions. Such early stage discussions increasingly include embodied carbon considerations, where bio-based options often appear to be the preferred choice for meeting sustainability goals. CRH, a material supplier specializing in heavyweight construction solutions, observes that this framing is incomplete: it rarely accounts for energy flexibility, i.e., the ability of a building to use its thermal mass to shift heating and cooling demand in time under comfort constraints. This capability is becoming increasingly valuable as electrification and variable renewable generation intensify grid congestion, price/CO鈧� volatility, and midday PV surplus versus morning/evening peaks of energy demands. Yet, energy flexibility is rarely assessed at the concept stage because it depends not only on construction type but also on e.g. massing, thermal-mass exposure, and HVAC emission concept, and most quantification methods require detailed inputs which are available only in later phases, after key choices are locked in. This creates a clear need for an early-stage decision-support approach that can provide credible, comparable energy flexibility indicators to support fair comparison of construction and system concepts alongside energy, cost, emissions, and comfort.

This EngD project, carried out as a collaboration between 黑料福利网 and CRH, addresses that need by developing InFlexion, an early-stage decision-support digital tool to quantify energy flexibility potential. The outcome of this project is not a working tool, but a method and an implementation blueprint behind InFlexion, designed to remain credible and usable with limited concept-stage input. A key contribution of this project was turning an open request (鈥渄evelop a sustainability tool鈥�) into an engineered brief. In this step, the intended users, the decision moment, and CRH interest were clarified. The missing value in early-stage comparisons was also identified: the thermal mass utilization for demand shifting under comfort constraints.

The development followed a methodological design approach. Iterative stakeholder engagement was combined with systematic testing of modelling choices and the key factors that influence energy flexibility. These tests informed which inputs were retained in the tool and which could be simplified without undermining credibility. Several workflow and modelling alternatives were considered and compared before the final approach was selected. Back-end components were developed to make the method usable, enabling rapid feedback in stakeholder discussions while keeping required inputs minimal without sacrificing credibility.

The technical foundation of InFlexion is dynamic building performance simulation using EnergyPlus, a widely used simulation engine for whole-building energy modelling. All modelling and testing in this project were carried out in DesignBuilder, with EnergyPlus used as the underlying simulation engine to provide credible results.

After the development process, InFlexion is designed as a workflow with five core blocks:

1. Early-stage inputs (kept intentionally minimal: archetype, climate, basic massing/topology indicators, candidate construction/HVAC concepts, and objective selection).
2. Mapping from building shape to group of shoebox models, using a simplified representation of building form (bitmap-based) to derive interpretable geometry indicators for selecting representative simulation cases.
3. A pre-simulation database that stores energy flexibility responses across discrete configurations, enabling instant retrieval instead of slow annual simulation during meetings.
4. A group of objective-driven, rule-based control logics, and KPI computation for: cost, emissions, peak reduction, and PV utilization, all under comfort constraints.
5. Scaling and reporting, normalizing results per m虏 and scaling to building level to generate outputs and a concise one-page summary suitable for stakeholder discussion.

The goal of the tool is to enable robust option screening and trade-off clarity at the time key choices are still reversible. Using InFlexion, the user defines a concept scenario using only early-stage information: building function, location, a coarse description of geometry and surrounding context, and key design choices that affect thermal storage and coupling (construction type, f inishes, false ceilings, and HVAC emitters). The user then selects an objective (peak reduction, PV utilization, cost, or CO鈧�). InFlexion retrieves baseline and flexibility-enabled results from a pre-simulated database (or interpolated equivalents where implemented) and evaluates them under consistent boundary conditions and explicit comfort constraints. The results are presented as side-by-side changes in the KPIs (baseline vs. flexibility), showing both the gains and any rebound effects, so options can be compared through clear trade-offs rather than a single score, because energy flexibility only counts when it shifts demand without causing unacceptable comfort problems or counterproductive rebound effects.

In practice, the tool is used to support early-stage conversations such as:

• 鈥淚f we choose between timber and concrete structure, what flexibility do we gain/lose under comfort constraints?鈥�
• 鈥淒oes radiant emission meaningfully increase usable thermal mass compared to radiators?鈥�
• How do surrounding buildings change heating/cooling dominance and energy flexibility potential?鈥�

By enabling questions like these to be answered quantitatively, the tool positions energy flexibility potential as a design criterion rather than an afterthought, and prevents misleading decisions driven by narratives of considering only embodied carbon or metrics that only measure annual energy consumption.

InFlexion gives CRH a practical way to communicate the flexibility value of heavyweight structures in the early stages of building design, using comparable KPIs. The value of the tool lies on the modelling choices that make these comparisons credible with limited inputs. Influencing factors were tested and prioritized to decide what must be represented explicitly at concept stage, such as construction mass level and exposure, HVAC emitter type and its coupling to the mass, and context shading. Other aspects were simplified when they did not change the main conclusions. Based on these tests, a minimal input set and a consistent modelling framework were defined. The aim was to keep the workflow fast and usable, while still capturing the dominant flexibility mechanisms and the risk of rebound effects. This knowledge contribution, what to include, what to simplify, and how to represent each element in the model, forms the methodological backbone of InFlexion and supports fair comparison of heavyweight solutions alongside embodied carbon, energy, cost, and comfort. In doing so, InFlexion can contribute in CRH鈥檚 shift from late-stage material supplier to earlier-stage solution partner, equipped with defensible evidence to guide robust concept choices.

Funded by: CRH