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Many practising consultants can quickly identify and preach across the economic, environmental and human health benefits of a built environment that is environmentally sustainable centric. However, the consciousness of that benefit truly starts with a transformation of the design process itself. An Integrative design process seeks to engage all project team members, including operational and maintenance team, in discovering beneficial synergies between systems and components in the early design phase. Many common building performance gaps today exist simply due to the lack of holistic design charrette between consultants that lead to overlapping relationships, services and redundancies among systems.
Using the VE for an Integrative Design Process
At IES, we cannot emphasise enough the significance of this integrative design process. Our development team has made splendid updates in the past few releases that are integration and interoperability thematic (view VE2018 updates, view VE2019 updates). These updates assist your facilitation of an integrative design approach by navigating through the myriad of building physics uncertainties confidently. One prime example is the building façade system. The building envelope remains as one of the most discussed items in a project as it encompasses many considerations from all disciplines.
Daylighting assessment is one of the many integrative design elements of a building envelope. It assesses the practical approach of harnessing a comfortable level of daylight for various visual comfort goals under differing climate and sky conditions. The irrefutable list of growing literature on the benefits of daylighting has concluded both physiology and psychology benefits of a healthy working environment.
The aim is to supplement or replace existing artificial luminaires with natural daylight to conserve lighting energy while ensuring visual comfort. However, the daylighting design process requires a significant determination to ensure the implementation of the design as intended. Here are three examples that substantiate the need for an integrated Radiance tool to evaluate the impact of daylight throughout the integrative design process:
1. Climate Based Daylight Modelling (CBDM) and unique geometric massing
Achieving daylighting levels to meet the criteria of various daylighting credit from different assessment tools is not always straightforward. Unlike previous daylight modelling approaches of considering a static sky condition and specified time frames, CBDM holistically takes into consideration the seasonal variations of sunlight throughout. This updated assessment metric quickly translates the sincerity of the daylight credit approach as each building façade has its unique solar map across the dynamic sun and sky conditions. My colleague has further elaborated on the significance of CBDM HERE.
The integrative design approach allows the design team to address the concern of daylighting against the geometric massing and facade at the early stage. Such example is the impacts of types of shading device, self-shading and neighbouring obstacles on the quality and quantity of daylight for each space. Or, can we specify a reduced thermal performance of our glazing since the façade has been self shaded from direct radiation? What is the cooling load reduction so we can efficiently size or stage our chillers? These are some of the many questions, along with the aspiration of the integrative design process.
2. Daylighting design is Incomplete without evaluating the impact of Interior Design
It’s one hurdle to score a daylighting credit, yet many more considerations to ensure that daylighting works. It is relatively common to have building design consultant simulating an empty office space with the necessary material specifications and CBDM approach as instructed by LEED or other assessment frameworks. Sure enough, the consultant does not know what the interior finishing and fittings look like before occupants proceed to fit out the interior spaces. The impact of interior elements towards the ambient bounce of incoming daylight, which also affects the positioning of the daylight sensor with artificial lighting circuit, remains unknown and certainly will affect the outcome of daylighting strategy.
The simple shoebox room quickly shows the significant impact of an arbitrary interior layout that has given obstructions to incoming daylight. A genuine design consultant should look beyond the credit and into mitigating this consequence. With an integrative design process, the tenancy agreement or Green Lease could encourage and educate tenants to evaluate their interior planning to ensure the design intent is handed over to the tenant’s designer. The RadianceIES application within VE has an array of pre-built components for you to evaluate such scenarios across many space typologies such as office, school, hospital, apartments etc.
3. Accurate Daylight Linked Dimming controls during the design phase
How do you know where to place your daylight sensor? What should your dimming controls for artificial lighting be? How many numbers of lighting circuits correspond to that? Having a good daylight design is not complete without a perfectly synced artificial lighting design and controls. Conventionally, the feasibility and also accuracy of placement of light sensors are only verified during the commissioning process.
However, the integrative design process aims to discuss these details during the design onset, much earlier before the artificial lighting layout is proposed. With the sensors feature within the RadianceIES application, you can assign formula profiles that will dictate the lighting gain, which corresponds to the illuminance level. Thus, instead of the conventional approach of sizing cooling plants with the assumption of a saturated lighting gain, we can accurately predict the electricity consumption of both the lighting and cooling plant.
In the next article, I will cover the five key strategies for daylighting in the Tropics.
If you have any feedback on improving the RadianceIES application, please contact feedback@iesve.com. If you are interested in enquiring about our consultancy service, please contact us here.
If you want more information on our Lunch-N-Learn videos, or any advanced training session, please contact training@iesve.com for more details.
Further reading and training links:
• On-Demand – Daylight Simulation, Glare modelling and Lighting Energy Calculations
• On-Demand - Using the IESVE to model Daylight Linked Dimming for Thermal Simulations
• On-Demand – Using the IESVE to conduct Climate Based Daylight Modelling (CBDM) Studies
• Article - Ten Key Daylight and Electric Light Metrics
