Ventilation, thermal and luminous autonomy metrics for an integrated design process

Ko, Won Hee; Schiavon, Stefano; Brager, Gail; Levitt, Brendon

doi:10.1016/j.buildenv.2018.08.038

Cited by 23 publications

(19 citation statements)

References 44 publications

(50 reference statements)

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“…These so-called "massing studies" do not need to be geometrically detailed; their purpose is to help build consensus on which issues and ideas to prioritize and develop further. Measures for shape compactness [12] and parametric "shoe-box" models [13][14][15][16][17] can help design teams establish the proportions and parameters that govern energy efficiency. These guidelines and studies may be suitable for generic planning, real estate, or renovation projects, but may lose their relevance for cultural landmarks-such as some civic buildings, corporate headquarters, or mixed-use developments-where the team must pay special attention to the form and network of Figure 2: The functional systems of a modern building (adapted from [11]).…”

Section: Social Networkmentioning

confidence: 99%

The Optimal Tuning, within Carbon Limits, of Thermal Mass in Naturally Ventilated Buildings

Craig¹

2019

Preprint

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What proportions should a thermally massive building have? How should the thermal mass be distributed? Should the "massing" change with the choice of material? This paper shows how to optimize the physical proportions of a building so that it synchronizes ambient heat exchanges in a natural feedback cycle. An internal mass is thermally coupled with buoyancy ventilation; the cycle is driven by the daily swing of outdoor temperature. Tripling up functions in this way—so that structural materials can reliably cool and power the ventilation for buildings—could help decarbonize the construction industry and provide an effective strategy for adapting to life-threatening heatwaves. Based on harmonic analysis, the method allows designers to thermally tune the form and mass of a building to meet chosen targets for temperature and ventilation in free-running mode. Once the optimal balance of exchange rates is known, design teams can proportionally vary the building height and ventilation openings against the surface area and thickness of an internal thermal mass. The possible permutations are infinite but parametrically constrained, allowing teams to fairly compare the functional and environmental credentials of different construction materials while they produce and evaluate preliminary options for organizing the exterior form and interior spaces of a building. An example study suggests that thin-shell structures of minimum weight, and even timber buildings, may be optimally tuned to produce ample ventilation and temperature attenuation.

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Section: Social Networkmentioning

confidence: 99%

The Optimal Tuning, within Carbon Limits, of Thermal Mass in Naturally Ventilated Buildings

Craig¹

2019

Preprint

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“…A key concept emerging in building energy resilience is "passive survivability", which denotes the ability of buildings to keep occupants safe and comfortable during a power outage [24]. "Thermal autonomy" has been proposed to assess a building's potential to keep occupants at acceptable temperatures, with the metric ultimately consisting of the time occupants are kept in these sufficient thermal conditions [24,25]. Similarly, as another time-based metric, "hours of safety" has been proposed as a metric to assess the potential of a building to keep people safe from extreme cold and heat during a power outage, attributing resilience to the performance of thermal comfort-associated building components, such as insulation [26].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Energy Resilience of Office Buildings: Development and Testing of a Simplified Metric for Real Estate Stakeholders

Mathew¹,

Sanchez²,

Lee³

et al. 2021

Buildings

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Increasing concern over higher frequency extreme weather events is driving a push towards a more resilient built environment. In recent years there has been growing interest in understanding how to evaluate, measure, and improve building energy resilience, i.e., the ability of a building to provide energy-related services in the event of a local or regional power outage. In addition to human health and safety, many stakeholders are keenly interested in the ability of a building to allow continuity of operations and minimize business disruption. Office buildings are subject to significant economic losses when building operations are disrupted due to a power outage. We propose “occupant hours lost” (OHL) as a means to measure the business productivity lost as the result of a power outage in office buildings. OHL is determined based on indoor conditions in each space for each hour during a power outage, and then aggregated spatially and temporally to determine the whole building OHL. We used quasi-Monte Carlo parametric energy simulations to demonstrate how the OHL metric varies due to different building characteristics across different climate zones and seasons. The simulation dataset was then used to develop simple regression models for assessing the impact of ten key building characteristics on OHL. The most impactful were window-to-wall ratio and window characteristics. The regression models show promise as a simple means to assess and screen for resilience using basic building characteristics, especially for non-critical facilities where it may not be viable to conduct detailed engineering analysis.

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“…These scores were derived using pre-defined visual and thermal thresholds, calculated for each of the six occupants of the room (Figure 3). The method is adapted from Ko et al (2018), who combined multiple environmental metrics using the concepts of luminous, thermal and ventilation autonomy (i.e., with the use of fully-passive heating and cooling) to define the comfort thresholds, and conducted a spatial analysis rather than a conventional single-node evaluation. However, in the present study, the calculation of the visual and thermal comfort scores differed from that presented by Ko et al (2018).…”

Section: Energy and Discomfort Indicatorsmentioning

confidence: 99%

“…The method is adapted from Ko et al (2018), who combined multiple environmental metrics using the concepts of luminous, thermal and ventilation autonomy (i.e., with the use of fully-passive heating and cooling) to define the comfort thresholds, and conducted a spatial analysis rather than a conventional single-node evaluation. However, in the present study, the calculation of the visual and thermal comfort scores differed from that presented by Ko et al (2018). The "thermal comfort score" (TCscore) for each design variation was calculated on the basis of the PVM results for each hour and each occupant.…”

Section: Energy and Discomfort Indicatorsmentioning

confidence: 99%

“…Another goal of the paper is to describe an evaluation method for a multi-criteria analysis (considering energy and both visual and thermal comfort) applicable for different glazing technologies. The most relevant part of this evaluation is the calculation of the discomfort indicator with a comfort evaluation matrix, examining at the same time different aspects of thermal and visual comfort rather than considering them as separate indicators, on the basis of the work proposed by Ko et al (2018).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Energy Performance And Occupancy-Based Analysis Of Visual And Thermal Comfort For Transmittance Level And Layout Variations Of Semi-Transparent Photovoltaics

Chinazzo¹,

Legrain²,

Peronato³

et al.

Building Simulation Conference Proceedings

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This paper investigates the impact of transmittance level and layout variations of semi-transparent photovoltaics (STPV) on both energy performance and occupancybased visual and thermal comfort, simulating a reference office with a fully south-oriented glazed surface. Four transmittance levels (20, 30, 40, and 50%) were investigated, first uniformly distributed on the full glazing (i.e., one specific transmittance for the entire glazing) and then considered in combination (i.e., with the glazing divided in equal-height bands with different transmittance levels). Simulations were conducted in three climatic conditions: temperate (Geneva), hot-arid (Casablanca), and cold (Helsinki). Following the proposed energy and occupancy-based visual and thermal comfort analysis, the best design option for both Geneva and Helsinki climate resulted in the 2-level STPV design variation with 50% visible transmittance on top of the glazing. In Casablanca, the 1-level design variation with the lowest visible transmittance (20%) uniformly distributed resulted as the best choice. This work, besides offering a first exploration of the relationships between climatic context and STPV design variations, describes a spatial multi-criteria analysis method that could be applied for the evaluation of other glazing technologies.

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Ventilation, thermal and luminous autonomy metrics for an integrated design process

Cited by 23 publications

References 44 publications

The Optimal Tuning, within Carbon Limits, of Thermal Mass in Naturally Ventilated Buildings

The Optimal Tuning, within Carbon Limits, of Thermal Mass in Naturally Ventilated Buildings

Assessing the Energy Resilience of Office Buildings: Development and Testing of a Simplified Metric for Real Estate Stakeholders

Energy Performance And Occupancy-Based Analysis Of Visual And Thermal Comfort For Transmittance Level And Layout Variations Of Semi-Transparent Photovoltaics

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