This study was undertaken to investigate the effectiveness of an integrated natural ventilation design for a NetZero energy house in maintaining occupants comfortable solely by passive means. The house was instrumented and monitored during the warmest months of the year. A dynamic thermal model and a computational fluid dynamics (CFD) model were developed to supplement the measurements and help to understand the factors that contribute to the effectiveness of the design. A methodology was developed to validate the models with data and cross-validate them. Adaptive thermal comfort is used as the metric to determine if comfort has been achieved. The study concludes that the house as a whole meets the comfort target. Two technologies were compared through simulations to evaluate their effect on enhancing wind-induced natural ventilation. The technologies did not improve cooling performance in a significant manner. Further work is needed to improve the models through technologies testing in the laboratory and model the uncertainty of the boundary forces to increase confidence in the results., Peer reviewed, Peer reviewed article, Published online: 06 Sep 2016., Adaptive thermal comfort, Natural ventilation, Active house, NetZero energy house
The thermal environment was studied in two operating rooms at the Montreal General Hospital. Thermal comfort of the staff was assessed based on measurements of the environment during surgical operations and on questionnaires given to the staff. Infrared pictures of representative surfaces and people were also taken and, when possible, skin and core temperatures of the patient were also measured. The thermal resistance of clothing and the activity levels for all the people were estimated from published tables and previous research studies. Three thermal zones were studied: zone 1, bounded by the patient, the surgical staff, and the surgical lights; zone 2, the adjacent area; and zone 3, the farthest one. It was found that under the present environmental and personal conditions it is not possible to provide all groups of people with an acceptable thermal environment. In general, surgeons tend to feel from slightly warm to hot (they sweat very often), anesthesia staff and nurses from slightly cool to cold, and the patient from slightly cool to very cold (patients sometimes woke up shivering). In addition to questionnaires, thermal comfort was predicted based on Fanger ' PMV model, which assumes a uniform thermal environment. Based on Fanger's model, the air temperature that could have ensured satisfactory thermal comfort for the surgeon, under the particular conditions studied, was about 66 deg F (19 deg C). However, at that temperature, to remain in good thermal comfort, nurses and anesthetists must be clothed with at least 0.9 clo and the patient covered with at least 1.6 clo. In practice, however, the radiant temperature asymmetry from the surgical lights in zone 1, which ranges between 11 deg F (6 deg C) and 137 (7 deg C) over the operating table and between 18 deg F (1O deg C) and 22F (12 deg C) over the floor (at a level of 1.1 m), causes surgeons' dissatisfaction with the environment at any air temperature. Possible solutions to minimize radiation and its effects on the surgeons are discussed, which would permit ambient temperatures more favorable for the patient and all the staff., Peer reviewed, Conference proceeding, Published: 2001.
A series of eleven case studies were gathered from across Canada in the summer of 2002. These case studies define an initial compendium of Best Practice in the use of information technology (IT) in Canada. The professionals interviewed included architects, engineers, general contractors, and owners. Many of them are at the cutting edge in their use of IT. The documentation of their pioneering use of IT can demonstrate how useful these technologies can be and what potential pitfalls are of concern. The case studies cover architecture, engineering, construction management, and specialized contractors. The following technologies were demonstrated: 3D CAD; custom Web sites; commercial Web portals; and in-house software development. No case was found that used wireless communication or standardized data formats such as IFCs or CIMSteel. The following issues were identified: the electronic distribution of documents is more efficient and cheaper; the short time-line and the tight budgets make it difficult to introduce new technologies on projects; the industry is locked in one CAD system and it is difficult to introduce new ones; it is costly to maintain trained CAD and IT personnel; and companies that lag behind reduce the potential benefits of IT. Still, the industry could achieve substantial benefits from the adoption of IT if it would be more widespread., Peer reviewed, Peer reviewed article, Submitted: August 2003 ; Revised: January 2004 ; Published: February 2004, Information technology, Technology use, Case studies, Architecture, Engineering and construction industry, Canada
A 2015 ASHRAE news release corrected the assumption that thermal comfort research included only middle-aged men in suits working in offices.(1) Standard 55 is gender neutral and can be applied to most environments where people go-including into homes. ASHRAE stands behind this assertion through a 2014 interpretation, and includes the standard in its residential resources., Peer reviewed, Technical feature, Published., Standard 55, Thermal comfort
Computer support for conceptual design of building structures is still ineffective, mainly because existing structural engineering applications fail to recognize that structural design and architectural design are highly interdependent processes. This paper describes a computer representation called StAr (structure-architecture), aimed to act as a common basis for collaboration between architects and engineers during conceptual structural design. The StAr representation describes the structural system as a hierarchy of entities with architectural counterparts, which enables the direct integration of the structural system to the building architecture as well as engineering feedbacks to the architect at various abstraction levels. The hierarchical structural description implements a top-down design approach where high-level structural entities, which are defined first, facilitate the configuration of lower-level entities whose functions in turn contribute to those of the higher-level wholes that they belong to. The representation has been built on top of a geometric modeling kernel that allows reasoning based on the geometry and topology of the design model, which is paramount during early design stages. A proof-of-concept software prototype, called StAr prototype, has been developed and a test example demonstrates how the representation can support the different activities that take place during the conceptual design of building structures., Peer reviewed, Technical paper, Received: September 16, 2004 ; Accepted: October 27, 2004 ; Published online: March 01, 2006, StAr, Conceptual design
In northern coastal climates, surface condensation often occurs in fenestration systems during winter. The most common contributors of this phenomenon are air leakage, thermal bridging, local convection and radiation. (i.e. boundary conditions). Researchers and industry experts typically focus on improving designs of fenestration and developing different strategies to deal with air leakage and thermal bridging. However, the effects of local convection and radiation on window condensation are often overlooked. This project focuses on investigating the ways different heating systems internet with window-wall systems via convection and radiation heat exchanges, and their effects on surface condensation. The three most common heating systems for multi-unit residential building (MURB) arc considered: electric baseboard, hydronic radiant floor and forced air system. Each heating system provides vastly different indoor conditions due to differences in thermal stratification, room air distribution and location of heat sources. These differences have direct impacts on window performance and potentially increase risk of condensation. In this project, the following questions are investigated: How significant is impact of room air flow on condensation risk in window-wall systems? Are empirical film coefficients sufficient for predicting condensation risk of window-wall units' What are the differences between each of the heating systems on condensation risk? This project designed a methodology in an attempt to better understand and predict these physical phenomena and will hopefully guide further efforts to better characterize the effect of different heating systems in window condensation risk analysis., Peer reviewed, Peer reviewed article, Published.
During the design of a new building or retrofitting of an existing one, it is important to reliably assess the indoor humidity levels of the building as it can potentially affect the building envelope durability, occupants? comfort and health risks associated with mould growth. Simplistic assumptions of indoor humidity profiles, which ignore the dynamic coupling of the indoor environment and building enclosure, may lead to inaccurate conclusions about the indoor environment and moisture performance of the building enclosure. In this paper, a whole-building hygrothermal model called HAMFitPlus, which takes into account the dynamic interactions between building envelope components, mechanical systems and indoor heat and moisture generation mechanisms, is used to assess the indoor humidity condition of an existing occupied house. HAMFitPlus is developed on SimuLink development platform and integrates COMSOL multiphysics with MatLab. The basic input parameters of the model are discussed in detail, and its simulation results are presented. In general, the HAMFitPlus simulation results are in good agreement with the measured data., Peer reviewed article, Published article and manuscript
Computer support for conceptual structural design is still ineffective. This is due, in part, to the fact that current computer applications do not recognize that structural design and architectural design are highly interdependent processes, particularly at the early stages. The goal of this research is to assist structural engineers at the conceptual stage with early digital architectural models. This paper presents a geometric modeling framework for facilitating the engineers’ interactions with architectural models in order to detect potential structural problems, uncover opportunities, respect constraints, and ultimately synthesize structural solutions interactively with architectural models. It consists of a process model, a representation model and synthesis algorithms to assist the engineer on demand at different stages of the design process. The process model follows a top-down approach for design refinements. The representation model describes the structural system as a hierarchy of entities with architectural counterparts. The algorithms rely on geometric and topologic relationships between entities in the architectural model and a partial structural model to help advance the synthesis process. A prototype system called StAr (Structure–Architecture) implements this framework. A case study illustrates how the framework can be used to support the conceptual structural design process., Peer reviewed, Peer reviewed article, Received 24 October 2005 ; Revised 5 February 2007 ; Accepted 8 March 2007 ; Available online 3 December 2007., Geometric modeling, Conceptual structural design, Integrated design, Architectural design
The growing interest in industrial applications of the hemp plant requires alternative solutions for disposing of hemp waste. At the same time, the concrete industry is seeking ways to reduce its environmental impact, which could be realized by partially replacing Portland cement with more sustainable materials. In this study, a two-step valorization strategy of hemp waste is explored, including the use of hemp waste as biofuel and the addition to concrete of the biofuel by-product, hemp ash, as partial cement replacement. Hemp waste was incinerated in a muffle furnace at different combustion regimes and the residual hemp ash was analyzed before being added to some concrete mixes. Concretes with different hemp ash replacements (5–25% by cement weight) were tested for compression strength, air content, workability, and water absorption. Results showed that hemp ash has the potential to be added to concrete as a filler to reduce environmental impact and costs at 5% cement replacement., Peer reviewed, Article, Received: December 10, 2019. Accepted: March 27, 2020. Published online: April 2, 2020., Incineration, Hemp biomass, Biofuel, Hemp ash, Supplementary cementing materials, Cement, Concrete
Carbonation in concrete is a natural chemical process by which atmospheric CO2 reacts with calcium oxide in the Ca(OH)2 and CSH phases in hydrated cement paste to form CaCO3. The carbonation rate in the atmosphere is too slow for laboratory testing, and therefore, it is usually accelerated by using relatively higher CO2 concentrations. However, there exists some disagreement as to what CO2 concentration, humidity and temperature should be specified when conducting an accelerated carbonation test. In this study, samples of hydrated cement paste were carbonated at different CO2 concentrations, and analysed using the x-ray diffraction technique. The results show that the morphology of CaCO3 formed at higher CO2 concentrations is different from that of CaCO3 formed at natural concentrations. It should be recognized that the diffusion coefficient measured at higher concentrations will not be exactly the same as that from naturally carbonating concrete due to the formation of these morphologically different products., Article, Published.