Longueuil, Canada
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Moreau V.,CIRAIG | Bage G.,Dessau | Marcotte D.,Ecole Polytechnique de Montréal | Samson R.,CIRAIG
Journal of Cleaner Production | Year: 2012

In evaluating the impacts of products and processes, life cycle assessment has taken a prominent role. Missing data, however, continue to affect the completeness and accuracy of such environmental assessment tools. Data are missing for many reasons, for specific processes, at random in existing inventories or worse, nonexistent. This article proposes a statistical approach to address the lack of data in life cycle inventories and applies it to hydroelectric power plants. Among large power production technologies, hydroelectricity varies considerably in scale and from one site to another. The procedure relies on relationships between the technical properties of a system or process, in this case hydropower plants, and the embodied material and energy flows in construction, operation and eventually dismantling. With highly flexible estimators known as kriging, predicting the value of material and energy flows becomes more accurate. From relatively small sample sizes, kriging allows better estimation without averaging out any of the observed data. Similarly, parameter estimation and model validation can be performed through cross validation which assumes very little on the data itself. Calculations of mean absolute errors for various forms of kriging and regression show that the former estimates the values of material and energy flows more accurately than the latter, more so in cases of incomplete data. Accounting for several technical characteristics as well as joint estimation of covariate material and energy flows provide different ways to further reduce the errors and improve the completeness of inventories where data are missing. The specificity of hydroelectric power makes existing inventory data largely unrepresentative and kriging offers new possibilities to increase the reliability of estimated, representative data. © 2012 Elsevier Ltd. All rights reserved.

Velev N.,Dessau | Fortier J.,Dessau | Lemay C.,Dessau | Legeron F.,Université de Sherbrooke
Proceedings, Annual Conference - Canadian Society for Civil Engineering | Year: 2013

This paper examines the seismic rehabilitation of a twin bridge on Highway 10 crossing the Richelieu River near Montreal (Canada). Each viaduct consists of 19 simply-supported spans and a three-span continuous section, for a total length of 895 m. It was constructed in 1963 with separate deck for each direction. The piers are supported by shallow foundations, some common for both viaducts at certain locations. The bridge was evaluated and its seismic resistance was found to be inadequate, not even being able to sustain a moderate earthquake. The structural deficiencies observed were mainly non-ductile columns and seismically deficient footings. Based on the evaluation, it was decided to perform a seismic retrofit. Taking advantage of the separated decks, two different performance levels were chosen by the client: Importance Category "Other" for the South Viaduct and "Lifeline" for the North Viaduct. Also, two types of isolators were used: elastomeric bearings for the South Viaduct while friction pendulum bearings were employed on the North Viaduct. The analyses demonstrated that the isolation significantly reduces the forces transferred to the foundations and hence no additional retrofit is necessary for the piers and foundations. This presentation will also present the results of different analysis techniques: from simplified analysis using target characteristics of the isolation system, to non-linear time-history analysis with characteristics determined by large-scale testing. The presentation highlights the differences between the analysis techniques as well as those between both isolation systems. The detailing, durability and the design strategy for the common foundations are discussed as well.

Bourdages C.,Dessau | Brodeur O.,Dessau
ASHRAE Journal | Year: 2012

The Cartierville YMCA offered aquatic, sports and recreation facilities. The project was made possible due to an innovative public-community partnership between the Quebec government, the City of Montreal, and the YMCA. The owners mandated an energy-efficient HVAC design that would become a focal point of this environment-friendly building. The mechanical engineering team was able to craft a self-financing project designed to reduce energy consumption by 54% by combining renewable geothermal energy and heat recovery systems. Energy simulation models were used to evaluate different scenarios to help designers target the most energy and cost-efficient HVAC systems. The simulation software simultaneously considered weather data, building envelope parameters, and complex building HVAC system interactions.

David E.,École de Technologie Supérieure of Montreal | Frechette M.,Hydro - Quebec | Zazoum B.,École de Technologie Supérieure of Montreal | Daran-Daneau C.,Dessau | And 2 more authors.
Journal of Nanomaterials | Year: 2013

Polyethylene/nanoclay specimens containing from 0 to 5% nanoclays were prepared from a commercially available premixed PE/nanoclay masterbatch containing 50% wt of nanoclay. The masterbatch was diluted to the desired concentration by adding PE along with various amounts of compatibilizer in order to achieve the best possible dispersion of the nanoclay platelets. The dielectric response of the compounded samples was investigated using a combination of time and frequency-domain spectroscopy in order to cover a wide frequency window. Both techniques were in good agreement when the time-domain data was transformed into frequency-domain data. Despite their low concentration, the addition of the dispersed nanoclays led to a significant alteration of the material dielectric response in the form of the appearance of various interfacial relaxation processes and an increase of charge carrier transport within the insulation material. Moreover, an onset of nonlinear charge transport process was observed at moderate fields for specimens containing a relatively low level of nanoclays. The high-field breakdown strength was shown to have been improved by the incorporation of the nanoparticles, particularly when the exfoliation was enhanced by the use of a maleic anhydride grafted polyethylene compatibilizer. © 2013 E. David et al.

Nichols L.,DESSAU | Lacoursiere M.-O.,DESSAU | Courchesne M.,DESSAU
ASHRAE Journal | Year: 2013

Design constraints at Montreal's Mount Royal, McGill University's McIntyre, led innovative electromechanical systems that significantly reduced the energy consumption of the building Pavilion. The new design had to include a great deal of extra heating capacity due to the increase in outside air supply. An interesting option involved recovering the heat generated by interior air conditioning to help in heating peripheral areas and incoming fresh air. The designers chose coils with a large temperature differential, which meant that return water could be used as a low-temperature system to supply the new heating system coils. A total of 13 glycol-based recovery coils were installed in the various exhaust vents and a network of pipes connected them to the preheating coils for the fresh air supply systems in an effort to recover energy from the exhaust air. The creation of a low-temperature heating system based on an existing high-temperature system made for an innovative design.

Lefebvre D.,Dessau | Richard G.,Dessau
WCTE 2014 - World Conference on Timber Engineering, Proceedings | Year: 2014

This article outlines the process and challenges involved in designing and building a new structure to span the Uupaachikus Pass in Mistissini, Quebec. The 160-metre-long bridge was designed using semi-continuous arches made of glued laminated wood (glulam) girders. The bridge is 9.25 metres wide and has spans of 37, 43, 43 and 37 metres. The glulam bridge features straight girders with a maximum length of 24 metres attached to 15-metre arched girders by means of steel plate assemblies. The arches are connected to the piers and abutments using pins.

Bourdages C.,Dessau | Freitas M.,Dessau
ASHRAE Journal | Year: 2011

Société Immobilière du Québec (SIQ), in a bid to restore the Cowansville Courthouse to its original function, designed an energy-efficient HVAC system with a low-performance building envelope. The project's goal was to recover as much energy as possible before tapping into geothermal energy. It was found that cooling and lighting systems can be progressively reduced to keep electrical peak demand below a critical setpoint. By sizing the ground loop to fit the building's cooling capacity, engineers sidestepped the need for extra cooling equipment. Designers made a detailed model of the geothermal system with the help of TRNSYS simulation software. By plugging in the hourly loads from the EE4 simulation model, designers could map out the appropriate number, depth and configuration of the geothermal boreholes to guarantee the system's stability.

Desmarais G.,Dessau
ASHRAE Journal | Year: 2011

Designers created efficient HVAC systems that reduce energy consumption by roughly 30% for the new expansion area and 10% for the rehabilitated portion of the Montreal's Pierre-Boucher Hospital that required a 100,000 ft 2 expansion including a new hospital wing, an operation block and laboratories due to a significant growth in ambulatory service needs. The works also included identification of energy recovery devices that directly reduce heating and cooling loads given that they are the most profitable. By designing a medium-speed principal air-distribution system, as opposed to typical high-speed air-distribution systems, designers were able to minimize fan power supply. The designers found that additional energy savings could be achieved by installing variable frequency drives on supply water pumps of chilled and low-temperature heating water, to modulate motor speed and water flow according to actual loads.

Molina J.,Dessau | Bourdages C.,Dessau
ASHRAE Journal | Year: 2011

The Riverside School Board, Montreal, decided to add a building to St. Johns School, a moderate-size public elementary and high school in order to create an affordable and eco-friendly building. The design team used a solar wall, a geothermal system and heat recovery for the 9,000 ft2 expansion building. Energy simulation models helped lower down the percentage of the maximum capacity that should be ensured by the geothermal system. The geothermal loop is used to treat fresh air and supply an hydronic radiant floor heating system, installed into the concrete floor slabs of the classrooms and library. A newly released BMS was selected because it offered better flexibility and a more user-friendly graphical interface than the other systems on the market. Energy simulation models helped designers predict energy savings of about 590 million Btu a year, an energy reduction of 55% compared to an equivalent building with standard HVAC systems.

Bourdages C.,DESSAU
ASHRAE Journal | Year: 2012

The Université de Sherbrooke's new Longueuil Campus emerged as one of the tallest structures on Montreal's South Shore in Canada decorated with a 16-story glass tower. The university sought to offer an open study environment to encourage interdisciplinary mingling and promote the development of new and emerging disciplines, inspired by an innovative view on education. The campus' bold architectural design focused on open spaces and gathering areas to promote a sense of community and cohabitation throughout the grounds. Its translucent building envelope maximized the use of natural light and enhances a majestic view of the green rooftop oasis. The new building bridges the gap between man-made structure and its environment by blurring traditional boundaries between indoor and outdoor spaces. Mechanical designers worked with architects to select a low SHGC glass to reduce summer cooling loads and downsize overall cooling equipment, increasing occupant comfort in the process.

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