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Kitchener, Canada

Samuelson H.W.,Harvard University | Ghorayshi A.,MMM Group Ltd. | Reinhart C.F.,Massachusetts Institute of Technology
2014 ASHRAE/IBPSA-USA Building Simulation Conference | Year: 2014

This paper evaluates the accuracy of 18 design-phase building energy models, used for documentation for LEED Canada certification, and analyzes the effectiveness of simple model calibration steps applied to these models. The calibration steps included inputting actual weather data, adding unregulated loads, revising process loads (often with submetered data), and updating a minimal number of other inputs. In net, the design-phase energy models under-predicted the total measured energy consumption by 36%. Following the above outlined calibration steps, this error was reduced to a net 7% under-prediction. For the monthly Energy Use Intensity (EUI) the coefficient of variation of the root mean square error improved from 45% to 24%. Revising the process loads was particularly important in these cases. This step alone increased the EUI by 32% on average (15% median) in the models. This impact far exceeded that of calibrating the weather data, even in a sensitivity test using extreme weather years. These results suggest that although compliance-type energy models can be poor predictors of actual energy use, practitioners may be able to make initial strides toward calibration with relatively little effort. © 2014 ASHRAE. Source


Schilleman B.,Stantec Inc. | Gough J.,MMM Group Ltd.
ITE Journal (Institute of Transportation Engineers) | Year: 2012

Sustainable transportation projects are increasingly important as the world population grows, resources shrink, and environmental impacts become more pervasive. Federal, state/provincial, and local rules, programs, and practices are already evolving in response to this emerging issue. ITE members are among the world's leaders in identifying and developing innovative and sustainable transportation practices, and are changing the standards for our industry. More than 480 responses to the survey were received from Australia, Canada, and the United States. The respondents provided a wealth of information in response to a 17-question survey, which encompassed current practices with respect to definitions, performance measures, organizational approaches to sustainability, funding, certification, and other topics. Source


Huang D.,Atkins North America | Arnold S.,Structures Office | Hu B.,MMM Group Ltd.
Transportation Research Record | Year: 2012

The purpose of the investigation reported in this paper was to identify the main causes of cracking that occurred in the Cross Florida Barge Canal Bridge, a three-span, continuous, spliced I-girder bridge that comprises spans of 77.7-86.9-77.7 m (255-285-225 ft) located in Citrus County, Florida. This paper briefly describes the bridge and the cracking. It then presents analytical models. Analytical results showed that the maximum vertical tensile force within a girder end zone from longitudinal prestressing strands was nearly 8% of the total prestressing force. The force was significantly higher than that prescribed by AASHTO specifications to determine the quantity of vertical reinforcement required at the ends of pretensioned members. Finally, the paper discusses some recommendations for end zone detailing. The results could help bridge designers provide better bridge detailing and further mitigate cracking in prestressed, spliced I-girders. Source


Durif C.M.F.,Norwegian Institute of Marine Research | Fields D.M.,Bigelow Laboratory for Ocean Sciences | Browman H.I.,Norwegian Institute of Marine Research | Shema S.D.,Bigelow Laboratory for Ocean Sciences | And 7 more authors.
Journal of Plankton Research | Year: 2015

Ultraviolet (UV)-B levels are still increasing at high and polar latitudes where ozone depletion continues. Changes in the quality of algae at the base of the food web can have a cascading effect on higher trophic levels. We examined whether UVradiation altered the synthesis of fatty acids (FA) and mycosporine-like amino acids (MAAs), as well as the C:N elemental stoichiometry of marine primary producers and whether these modifications transferred through a simple food chain (copepod, fish larvae). Two diatoms (Thalassiosira weissflogii and Thalassiosira pseudonana) and one flagellate (Dunaliella tertiolecta) were exposed to three different UV exposure treatments. Copepod nauplii were then fed with Thalassiosira pseudonana for 3 days. Fish larvae were, in turn, fed with these nauplii. C:N ratios and total lipid decreased with increasing UVexposure in the diatoms, but did not vary in copepods or fish. PAR-only-treated algae had more saturated FAs, myristic (14:0) and palmitic acid (16:0), while UV-treated algae had more long-chain polyunsaturated FAs. These changes did not transfer to copepods or fish larvae. No MAAs were found in either algae, copepods or fish. Our results suggest that copepods are able to compensate for lower food quality by increasing food intake. © The Author 2015. Source


Samuelson H.W.,Harvard University | Ghorayshi A.,MMM Group Ltd. | Reinhart C.F.,Massachusetts Institute of Technology
Journal of Building Performance Simulation | Year: 2016

This paper evaluates the accuracy of 18 design-phase building energy models, built according to LEED Canada protocol, and investigates the effectiveness of model calibration steps to improve simulation predictions with respect to measured energy data. These calibration steps, applied in professional practice, included inputting actual weather data, adding unregulated loads, revising plug loads (often with submetered data), and other simple updates. In sum, the design-phase energy models underpredicted the total measured energy consumption by 36%. Following the calibration steps, this error was reduced to a net 7% underprediction. For the monthly energy use intensity (EUI), the coefficient of variation of the root mean square error improved from 45% to 24%. Revising plug loads made the largest impact in these cases. This step increased the EUI by 15% median (32% mean) in the models. This impact far exceeded that of calibrating the weather data, even in a sensitivity test using extreme weather years. © 2014 International Building Performance Simulation Association (IBPSA). Source

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