Building a comprehensive dataset for the validation of daylight simulation software, using complex "real architecture"

<p>This research focused on building a comprehensive dataset for use in validation studies of daylight simulation software. The aim of the set is to add to existing validation data to better cover a wide range of complexities and weather conditions. This will allow for not only the validation of simulation software, but the comparison of multiple simulators in their general strengths and weaknesses as well as feasibility for early ‘sketch’ design stages and complete building simulations. The set can also aid in the creation of valid simulation parameter starting points for designers. The research examined the current ‘gold standard’ validation dataset from the BRE-IDMP, and found that while it provides excellent validation opportunities for simulators that can support its detailed patch-based sky model; an equally high quality dataset is needed for simulators that support more simplified skies. This is essential as most of the weather data for annual daylighting simulations available to designers, such as the US-DOE’s collection of TMY data, can only be used in mathematical sky models such as the Perez all-weather model. It is also essential that real world, complex light-path scenarios commonly found in buildings be addressed by validation in addition to the simple single room, single opening tests which are prevalent in the daylight simulation field. A dataset suite is proposed, similar to the BESTEST suite for energy simulation, which covers basic analytical test cases for lighting simulators, simple office scenarios and a complex shaded classroom in a tropical climate. The dataset is valuable for the testing of daylight simulators which make use of the common CIE general or Perez all-weather skies. These datasets were used in a trial validation of Autodesk’s 3ds Max Design and Radiance, which included significant sensitivity testing of the two empirical datasets included in the suite. This demonstrated the usefulness of each dataset, and any issues with their data. It also highlighted the key inputs of any simulation model where designers must take significant care.</p>

Building a comprehensive dataset for the validation of daylight simulation software, using complex "real architecture"

<p>This research focused on building a comprehensive dataset for use in validation studies of daylight simulation software. The aim of the set is to add to existing validation data to better cover a wide range of complexities and weather conditions. This will allow for not only the validation of simulation software, but the comparison of multiple simulators in their general strengths and weaknesses as well as feasibility for early ‘sketch’ design stages and complete building simulations. The set can also aid in the creation of valid simulation parameter starting points for designers. The research examined the current ‘gold standard’ validation dataset from the BRE-IDMP, and found that while it provides excellent validation opportunities for simulators that can support its detailed patch-based sky model; an equally high quality dataset is needed for simulators that support more simplified skies. This is essential as most of the weather data for annual daylighting simulations available to designers, such as the US-DOE’s collection of TMY data, can only be used in mathematical sky models such as the Perez all-weather model. It is also essential that real world, complex light-path scenarios commonly found in buildings be addressed by validation in addition to the simple single room, single opening tests which are prevalent in the daylight simulation field. A dataset suite is proposed, similar to the BESTEST suite for energy simulation, which covers basic analytical test cases for lighting simulators, simple office scenarios and a complex shaded classroom in a tropical climate. The dataset is valuable for the testing of daylight simulators which make use of the common CIE general or Perez all-weather skies. These datasets were used in a trial validation of Autodesk’s 3ds Max Design and Radiance, which included significant sensitivity testing of the two empirical datasets included in the suite. This demonstrated the usefulness of each dataset, and any issues with their data. It also highlighted the key inputs of any simulation model where designers must take significant care.</p>

Evaluation of Multiyear Weather Data Effects on Hygrothermal Building Energy Simulations Using WUFI Plus

Transient building energy simulations are powerful design tools that are used for the estimation of HVAC demands and internal hygrothermal conditions of buildings. These calculations are commonly performed using a (often dated) typical meteorological year, generated from past weather measurements excluding extreme weather conditions. In this paper the results of multiyear building simulations performed considering coupled Heat and Moisture Transfer (HMT) in building materials are presented. A simple building is simulated in the city of Udine (Italy) using a weather record of 25 years. Performing a multiyear simulation allows to obtain a distribution of results instead of a single number for each variable. The small therm climate change is shown to influence thermal demands and internal conditions with multiyear effects. From this results it is possible to conclude that weather records used as weather files have to be periodically updated and that moisture transfer is relevant in energy and comfort calculations. Moreover, the simulations are performed using the software WUFI Plus and it is shown that using a thermal model for the building envelope could be a non negligible simplification for the comfort related calculations.

A large field study of relationship between indoor and outdoor climate in residential buildings

High-quality data on indoor climate and energy collected in buildings is required to deepen our understanding of building performance. The aim of this work was to investigate the relationship between the indoor and outdoor climate in Danish residential buildings. Field data was collected in 45 apartments from April 2019 to November 2020. Internet of things (IoT) devices were installed to record the temperature, relative humidity and CO2 concentration in the central corridor of each apartment. High CO2 concentration (above 1,000ppm) and overheating were observed in the apartments. The changeover between the heating mode and the free running mode occurred between 11.1 to 13.6°C of outdoor air temperature. The temperature setpoints of the heating systems were around 20.6-22.3°C, which could be useful values to feed building simulations in order to achieve more realistic predictions of indoor climate and energy. The results of this study improve our understanding of indoor environmental quality in residential buildings at a national level.

Too Hot to Stay at Home: Residential Heat Vulnerability in Urban India

Rising temperatures may lead to deadly heat waves in India. Combined with a growing urban population and mass production of affordable housing, this can sharply accelerate the demand for space cooling. India’s voluntary Energy Conservation Building Code - Residential (ECBC-R) or Eco Niwas Samhita 2018 limits thermal transmittance of the envelope. This research considers and critiques this approach through building simulation and an analysis of indoor comfort and severity of overheating during the summer months (April-May-June), in hot-dry and warm-humid climate zones. Code requirements neither vary with climate zones, nor is it adapted to future climate conditions. Our building simulations and analysis show that soon (2030s) parts of the country are likely to suffer from overheating 74% of time in summer. A minimally code compliant building would need air conditioning 90% of summer while a highly efficient iteration could reduce this by a third, in the hot-dry climate zone. Further, commonly used envelope assemblies are uncomfortably hot 77% (in the hot-dry zone) and 23% (in the hot-humid zone) of time in summer, on average. This analysis illustrates the vulnerability of current construction techniques to extreme heat and aims to avoid a long-term lock-in of inefficient, high energy consuming residential buildings.

Enumeration and comprehensive in-silico modeling of three-helix bundle structures composed of typical αα-hairpins

Background The design of protein structures from scratch requires special attention to the combination of the types and lengths of the secondary structures and the loops required to build highly designable backbone structure models. However, it is difficult to predict the combinations that result in globular and protein-like conformations without simulations. In this study, we used single-chain three-helix bundles as simple models of protein tertiary structures and sought to thoroughly investigate the conditions required to construct them, starting from the identification of the typical αα-hairpin motifs. Results First, by statistical analysis of naturally occurring protein structures, we identified three αα-hairpins motifs that were specifically related to the left- and right-handedness of helix-helix packing. Second, specifying these αα-hairpins motifs as junctions, we performed sequence-independent backbone-building simulations to comparatively build single-chain three-helix bundle structures and identified the promising combinations of the length of the α-helix and αα-hairpins types that results in tight packing between the first and third α-helices. Third, using those single-chain three-helix bundle backbone structures as template structures, we designed amino acid sequences that were predicted to fold into the target topologies, which supports that the compact single-chain three-helix bundles structures that we sampled show sufficient quality to allow amino-acid sequence design. Conclusion The enumeration of the dominant subsets of possible backbone structures for small single-chain three-helical bundle topologies revealed that the compact foldable structures are discontinuously and sparsely distributed in the conformational space. Additionally, although the designs have not been experimentally validated in the present research, the comprehensive set of computational structural models generated also offers protein designers the opportunity to skip building similar structures by themselves and enables them to quickly focus on building specialized designs using the prebuilt structure models. The backbone and best design models in this study are publicly accessible from the following URL: https://doi.org/10.5281/zenodo.4321632.

Beyond recovery: Measuring ventilation strategies and their impact on energy

Working with a medium scale, research-focused architectural practice this paper measures the efficacy of balanced pressure heat recovery ventilation systems (BPHR systems) in the existing housing stock as a strategy to mitigate thermal heat loss when incorporating ventilation strategies in New Zealand. Current research indicates that BPHR systems boast an efficiency upwards of 80%. The aim of this research is to determine at what point do BPHR systems meet current claims of efficiency. An examination of the existing New Zealand housing stock identifies that 66% of all dwellings do not meet thermal performance requirements. This has been attributed, in part, to the governance of legislation of minimum performance, which did not exist until 1978. This paper, first, identifies building simulation measures and assumptions to accurately simulate BPHR systems in controlled conditions, which is quality assured against the expected performance of a conventional code minimum residential building and a range of models that represent a spectrum of building leakage for pre-legislation buildings. This paper then examines passive ventilation strategies in each model to identify the energy balance of using BPHR systems and the potential for heating energy loss when implementing simpler ventilation strategies. This study identifies that the efficiency of BPHR systems significantly differ in the pre-legislation building simulations. In these models, the building leakage alone renders heat recovery negligible in comparison to simple passive design and occupant-controlled measures thatm achieve a similar result for the indoor air quality.

Beyond recovery: Measuring ventilation strategies and their impact on energy

Working with a medium scale, research-focused architectural practice this paper measures the efficacy of balanced pressure heat recovery ventilation systems (BPHR systems) in the existing housing stock as a strategy to mitigate thermal heat loss when incorporating ventilation strategies in New Zealand. Current research indicates that BPHR systems boast an efficiency upwards of 80%. The aim of this research is to determine at what point do BPHR systems meet current claims of efficiency. An examination of the existing New Zealand housing stock identifies that 66% of all dwellings do not meet thermal performance requirements. This has been attributed, in part, to the governance of legislation of minimum performance, which did not exist until 1978. This paper, first, identifies building simulation measures and assumptions to accurately simulate BPHR systems in controlled conditions, which is quality assured against the expected performance of a conventional code minimum residential building and a range of models that represent a spectrum of building leakage for pre-legislation buildings. This paper then examines passive ventilation strategies in each model to identify the energy balance of using BPHR systems and the potential for heating energy loss when implementing simpler ventilation strategies. This study identifies that the efficiency of BPHR systems significantly differ in the pre-legislation building simulations. In these models, the building leakage alone renders heat recovery negligible in comparison to simple passive design and occupant-controlled measures thatm achieve a similar result for the indoor air quality.

Future climate data for the building sector

&lt;p&gt;By mid-Century the Swiss Climate Scenarios CH2018 project an additional warming of 2-3 degree Celsius in Switzerland if greenhouse emissions continue unabatedly. In consequence, heatwaves become longer, more intense and more frequent, whereas coldwaves will be less common. Changes in the outdoor climate also affect the indoor climate in buildings where people spend a substantial part of their day to work, study, and live. Buildings are designed to last for several decades with limited possibility to update heating and cooling systems. Hence, the climate a building will face during its lifetime has to be considered in the planning process. In general, it can be expected that the heating demand will decrease whereas the cooling demand will increase in the near future. However, a holistic and quantitative assessment of the effect of climate change on the energy demand in buildings is still missing. For the use in building simulations, climate data at hourly resolution with physical consistency for a number of key variables such as temperature, humidity and radiation are required. To ensure that the use of the data is feasible in practice, the climate of the future needs to be condensed into a single year, representing typical mean conditions as well as typical deviations from the mean. In addition to the typical year, the assessment of an extreme year can provide information on the level of comfort during a once in a lifetime event and the performance at maximum capacity of the installations. Users of this data are practitioners in the building sector as well as officials from federal offices.&lt;/p&gt;&lt;p&gt;Our project aims to provide future climate data for the building sector at station level. For this, we make use of observations as well as climate change information from the Swiss climate scenarios CH2018. &amp;#160;Together with the users, we define criteria that shall be represented by the future typical and extreme years. We design different methods to create this years based on observations and scenarios and under consideration of existing standards and regulations. The methods are compared in a climatological assessment and sensitivities to emission scenario and time horizon are explored using building simulations. The results of this project support decision-making to optimize national and international norms and regulations and to design adaptation measures. The climate data will be made available to practitioners who can use them to plan the buildings of the future.&lt;/p&gt;