BCIT Thesis and other Required Graduate Degree Works | BCIT Institutional Repository

BCIT Thesis and other Required Graduate Degree Works

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The absorption and scattering characteristics of interior living walls
Installation of interior living walls is increasing rapidly due to their beauty, biophilic design and their potential contribution to indoor environmental quality. However, there is little understanding of the specific effect they have on the acoustics of a room. To advance the state of practice, this interdisciplinary study explores the acoustical characteristics of interior living walls to determine how they can be used to positively benefit room acoustic by reducing excess noise and reverberation. Specifically, the objective of the research is to measure the acoustical characteristics of the interior living wall in order to determine their absorption coefficient, scattering coefficient, and the parameters that most significantly impact these coefficients. First, a series of measurements are carried out in a reverberation chamber to examine random-incidence absorption by considering parameters such as carrier type, moisture content, vegetation type, and substrate. In addition, both absorption and scattering coefficients are examined by considering various vegetation types and coverage. The findings from empirical measurements facilitate a sensitivity analysis, with the use of the commercial software Odeon, of the absorption and scattering coefficients. Next, the empirical absorption and scattering coefficients are used on a model, developed in the commercial software Odeon, to see the effect of interior living walls on room acoustics. The aim of this study is to evaluate the application of interior living walls as a sustainable and acoustically beneficial material for buildings of any kind., Acoustical characteristics of interior living walls, Sound absorption coefficient, Sound scattering coefficient, Odeon software, Room acoustics, Living wall
Assessment of natural ventilation design and efficacy in a net-zero energy house
Achieving acceptable indoor environmental quality and thermal comfort in buildings can be difficult without relying on energy intensive mechanical equipment. When the climate conditions permit, natural ventilation could potentially help minimize the reliance on mechanically conditioned air; however, natural ventilation is rarely engineered. Houses are typically designed as fully enclosed climate systems in which the connection with the outdoor environment is rarely planned. Unlike in commercial or specialized buildings, houses are not designed with many energy conservation measures in mind. Reconnecting them with the outdoors has a great potential to increase thermal comfort and reduce reliance on mechanical systems. With such a connection to the dynamic weather conditions of the outdoors, it is difficult for architects to choose beneficial design elements to be included in the construction of their houses. Knowing which elements work and to what extent under particular conditions can potentially achieve increased thermal comfort using little or no energy. This research aims to offer a thorough assessment of a case study house and determine the effects of the design choices made by the architect of the house. This research may help architects know the risk factors affecting natural ventilation design in a systematic manner; and in doing so, enable quantifying the benefits of natural ventilation to meet the design goals of maintaining satisfactory indoor conditions without the use of air conditioning, particularly in the summer. A constructed net-zero case study house located in the Pacific marine climate of Canada was used to develop the proposed research. The house had been designed by an architect to rely solely on natural ventilation for cooling during the summer and much of the spring and fall. The house was instrumented and its indoor environment was monitored for a period of several months in 2014 to collect data to evaluate the effectiveness of design choices made, including the effect of a large atrium and the air flow characteristics of the windows intended by the architect to deliver most of the ventilation. Recorded data showed the house performed commendably and this was confirmed through evidence from the home owners. To aid in the understanding of the dynamics of the Harmony House, whole-building, multizone air flow network modeling and computational fluid dynamics (CFD) modeling of the house was developed and calibrated with monitored data and testing. The models were used to assess the indoor air quality and further quantify the natural ventilation of the house, as well as test hypothetical situations that were once considered for the house. Simulations revealed some additional insight into the design choices that were implemented in the house and showed that further technologies intended to increase ventilation were unnecessary and some instead, reduced ventilation through the house.
Assessment of natural ventilation using whole building simulation methodological framework
Natural ventilation is a passive alternative to provide both indoor air quality and thermal comfort for the building’s occupants with low energy use. But at the same time, it is challenging for the building designers to implement natural ventilation strategies due to its complexity and highly dynamic behaviour, especially when it is compared with the mechanically ventilated buildings. Nevertheless, the use of naturally ventilated buildings is increasing along with the use of passive strategies, but depending on the complexity of the project, the designer still use rules of thumb for the implementation of natural ventilation strategies instead of a more comprehensive simulation-based approach. In theory, whole building simulation models (WBSM) are becoming viable tools to support natural ventilation design, particularly in the early stages of the project where the impacts of measures to implement a natural ventilation strategy are magnified. However, the only “evidence” of such level of support comes from individual case-study projects. Nevertheless, there is a lack of validation through measurement of the effectiveness of natural ventilation design in real buildings. This research will shed light into the “inner-workings” of natural ventilation models in WBSM to answer fundamental questions such as the following: How is wind data processed? How are envelope openings characterized? How are internal openings modelled? When and how is air buoyancy modelled in spaces? How are the coupled thermal and fluid mass transfers modelled to reflect the dynamic thermal responses of constructions and airflows? Therefore, a methodological framework is developed in order to provide the necessary knowledge for natural ventilation assessment. This framework is based on simulation (WBSM) and field testing. The proposed framework is tested in an existing landmark building in Vancouver. A WBSM of that building is developed, calibrated, and used to analyze how different factors that compose an integrated natural ventilation strategy (like the building shape, window shading, thermal mass, indoor spaces functionality and connectivity, and local climate) influence the thermal comfort of its occupants., Natural ventilation, Thermal comfort, Adaptive model, Whole building simulation models (WBSM)
Comparing soil nematode composition in bluebunch wheatgrass P. spicata root to the occurrence of invasive plants C. stoebe and L. dalmatica
The viability of native bunchgrass ecosystems throughout the PPxh BEC subzone and in Kenna Cartwright Park (KCP) in Kamloops B.C. are under threat by invasive plants. Once established, invasive plants are difficult to eradicate and can predominate the landscape. I collected soil samples from a relatively undisturbed bunchgrass reference site composed of native bluebunch wheatgrass (Pseudoroegneria spicata), and I collected soil samples from a bunchgrass site occupied by the invasive plants, spotted knapweed (Centaurea stoebe) and dalmatian toadflax (Linaria dalmatica), to compare the soil nematode communities. My results reveal differences in the community-level biodiversity and abundance of soil nematodes between sites. The Maturity Index and the Plant Parasitic Index indicate that the native bunchgrass site had a “Structured” soil food web and that the site occupied by invasive plants had a “Basal” soil food web. My results indicate soil nematodes are useful as bioindicators of soil properties and these data provide useful criteria to help prioritize sites for ecological restoration., Nematology, Invasive plants, Pseudoroegneria spicata, Biological indicators, Ecological restoration
Development and application of an advanced green roof model
Green roofs are becoming a common application in order to improve building energy performance, runoff water control with several additional environmental benefits. Models are essential in the building science due to a necessity of prediction how different structures perform. This knowledge helps to choose right materials and material dimensions. A green roof structure is a complex system of different layers, including growing media and plants. Those two layers make the green roof modelling entirely different from ordinary modelling. Nowadays, several green roof models cover different phenomena and use different physical principles. However, a green roof model is still can be improved. Therefore, this study develops a green roof model- HAMFit-GR that better covers heat and moisture movement sources. The model is based on Heat-Air-Moisture model called HAMFit and Fast All-Season Soil Strength models from US Army Corps of engineers. A combined model is proposed to be more accurate than the most comprehensive green roof models. The result is achieved by adding uncovered components, such as coupling heat and moisture transport in growing media and runoff water flow. Green roof parameters that are required for accurate modelling are measured through laboratory and field experiments. The benchmark data is obtained from the field experiment that is being performed at Whole Building Performance Research Laboratory (WBPRL) of Building Science Centre of Excellence at British Columbia Institute of Technology (BCIT), Burnaby. A case study is prepared with the validated model. The case study includes analysis of green roof parameters impact on roof hydrothermal performance.
Eco-cultural restoration of wetlands at Tl’chés (Chatham Islands), British Columbia, Canada
My research project examined the restoration possibilities for two culturally important wetland ecosystems at Tl’chés (Chatham Islands, British Columbia, Canada). The first wetland is a sacred bathing pool and holds cultural significance, the second is a remnant silverweed and springbank clover (Potentilla anserine ssp. pacifica and Trifollium wormskjoldii) root garden. These wetlands are necessary ecosystems for the wildlife on Tl’chés as wetlands are rare, but also an integral part of Songhees’ cultural practices. My work was done at the invitation from elder Súlhlima (Joan Morris) who was one of the last resident of the islands and retains hereditary rights there, and Songhees Chief Ron Sam and band council. The goal of my project was to develop a restoration plan to restore the wetlands to pre-abandonment conditions, so cultural practices can continue, and to benefit the islands native plant and animal species. The project highlights the value of combining traditional ecological knowledge (TEK) and traditional resource and environmental management (TREM) practices with ecological restoration., Eco-cultural restoration, wetland ecosystems, traditional ecological knowledge (TEK), traditional resource and environmental management (TREM), estuarine root gardens, Songhees First Nation
The effect of mowing and hand removal on the regrowth rate of Himalayan blackberry (Rubus armeniacus)
Himalayan blackberry (Rubus armeniacus Focke) is an invasive species in the Pacific Northwest. Mowing and hand removal are two of the common treatments used for controlling Himalayan blackberry. I examined the effectiveness of mowing, hand removal, and control treatments by measuring the mean number of stem and mean stem length during a growing season. Treatments were applied on March 2017. Bi-weekly sampling was from April to August 2017. Data were analyzed with a two-factor split-plot Analysis of Variance (ANOVA) test. The overall trend showed no statistically significant difference between mowing and hand removal treatments in one growing season. Integrated treatments (e.g. mowing + hand removal + planting) are recommended to be used to effectively reduce Himalayan blackberry cover because one removal treatment showed to be insufficient to eliminate Himalayan blackberry., Himalayan blackberry
The effects of canopy closure on precipitation throughfall
Since the 1860s the watershed of Spanish Bank Creek has experienced many ecological disturbances due to extensive old-growth logging and urban development. Most notably, these disturbances have altered the vegetative composition and hydrology throughout the watershed. The historic old-growth forest has been replaced by species typical of earlier seral stages, as well as invasive species such as English ivy (Hedera helix). This disturbed vegetation mosaic is characterized by an arrested ecological trajectory that perpetuates degraded conditions. Urban development has eliminated over a third of the historic length of Spanish Bank Creek and storm drains were installed to direct residential drainage into the stream. The combination of a disturbed forest and degraded hydrology intensifies runoff and associated sediment transport, and decreases the hydraulic retention time of the watershed. This has led to a significant decline in abundance of chum, coho, and cutthroat salmonids in Spanish Bank Creek. Previous research has established how trees partition precipitation into throughfall, stemflow, and interception, however there are few studies examining the effects of canopy closure on throughfall within the context of ecological restoration. Thus, the objective of this paper is to determine if increasing canopy closure can be used as a restoration model to decrease throughfall, and consequently increase the hydraulic retention time of the watershed. Results indicated that greater canopy closure was associated with decreased precipitation throughfall. From these results I formulated a restoration goal and several treatments that would increase canopy closure, and also ameliorate the degraded vegetative composition and hydrology of the watershed. The restoration treatments prescribed in this paper constitute five years of physical enhancements from which self-sustaining biological processes will continue to restore ecosystem function and structure. Successful implementation of these restoration treatments will positively affect regional biota, as well as users of the Pacific Spirit Regional Park who come to recreate, learn, and connect.
Evaluating stream degradation in Villa De Allende, Mexico
I examined the anthropogenic effects on the water quality of headwater streams in the western mountains of the state of Mexico. Rural development has negative effects on the ecology of local streams by diverting and pumping surface and groundwater, removing riparian forests for the construction of buildings, roads, and agricultural fields, and dumping refuse in stream channels. Local development, construction, roads, and agriculture also are sources of pollution that enter the streams during rain events. These negative ecological effects are common to many streams in the watershed of the Chilesdo dam. The combined effects of human development negatively affect the quality of surface water and groundwater aquifers. The issue of anthropogenic effects on the water quality of headwater streams is relevant ecologically because of likely effects on flora and fauna that depend on these streams and because of the role of headwater streams in the context of the larger watershed. Effects on upstream areas directly affect people, animals, and plants downstream. This issue is relevant economically because rural communities depend on the availability of water of suitable quality for agriculture and livestock. In addition, local water quality directly affects the cost of water purification downstream at dams that feed the Cutzamala system, a major source of Mexico City’s drinking water. This issue is relevant socially because the local community depends on this water for domestic consumption. Compromising water quality and abundance could destabilize the lives of local people because poor water quality and water contamination are a public health concern. Additionally, climate change is likely to make this resource scarcer. Projections for all major scenarios used by the International Panel on Climate Change indicate elevated year-round temperatures and decreased overall precipitation in the region (IPCC 2013). I addressed concerns over water quality by testing differences among streams with anthropogenic alterations and a stream that had few anthropogenic alterations. I sampled benthic macro-invertebrate communities as indicators of water quality within the streams. Benthic invertebrates are a useful bio-indicator for water quality and environmental disturbances in river systems because different taxonomic groups of invertebrates have different tolerances to water pollution. I measured the abundance and taxonomic richness of invertebrates that exhibit different sensitivities to water quality. My results revealed that taxonomic richness was lower in streams that had anthropogenic alterations. My results also revealed that the abundance of “sensitive” and “somewhat sensitive species” were lower and that the abundance of “pollution-tolerant species” was higher in streams with anthropogenic alterations. The stream with few anthropogenic alterations had the highest taxonomic richness and largest number of sensitive and somewhat sensitive species. These results indicate that human activities are having negative effects on water quality. Given my results, I suggest that restoration of degraded streams should reduce water diversion, riparian encroachment, and refuse disposal. I propose solutions to guide these restoration efforts. My data suggests that a coordinated local and regional effort is required to reduce the negative effects of human development and to restore local streams to an ecological condition that will sustain water quality and quantity to enable local communities and the local environment to thrive.
Evaluation of educational-software and paper-based resources for teaching logical-thinking skills to grade six and seven students
Guided by the objectives of investigating whether there were any differences between the effectiveness of the paper-based materials and educational software in teaching logical-thinking skills and transferring those skills to new problems and determining the efficacy of the paper-based materials and educational software in teaching logical-thinking skills and transferring those skills to new problems, a mixed-method research approach was used. A qualitative assessment was conducted to ascertain the appropriateness of the materials and a quantitative assessment was done using a pre-test, post-test, experimental design to assess the effectiveness of the materials in teaching logical-thinking skills. Based on the qualitative analysis, after the initial materials were modified through the information gained from the pilot students and changes were put in as suggested by the reviewers through their iterative reviews of the materials, it was determined that the reviewers considered that the events of instruction addressed in this intervention (gaining attention, informing the learner of the learning outcome, presenting the material, providing learning guidance, eliciting the performance, providing feedback, assessing performance, and enhancing retention and transfer) provided the attributes needed to effectively teach the logical-thinking skills of classification, analogical reasoning, sequencing, patterning, and deductive reasoning. For the quantitative analysis, one-way ANOVAs were performed to compare an experimental group learning from educational software (32 students), an experimental group learning from paper-based materials (32 students), and a control group (32 students). Given significance was found between the groups, Tukey HSD Post Hoc Tests were done. For each test, the subjects taught through educational software and those taught through paper-based materials scored significantly higher in logical-thinking ability than the control group, except for the subskills of patterning and deductive reasoning for the subjects learning through educational software, and the skill of deductive reasoning for the subjects learning through paper-based materials. For the transfer learning scores, the subjects learning through paper-based materials scored significantly higher than the control group. There were no significant differences between subjects taught through paper-based materials and those taught through educational software on any test. Based on paired samples t-test results, the subjects learning from educational software and those learning from paper-based materials had significant percentage gains on all of their pre-test to post-test scores, except the subjects learning through paper-based materials showed no significant gains on the sequencing and deductive-reasoning skills., Logical thinking, Instructional design, Qualitative analysis, Quantitative analysis
Experimental investigation of living architecture design tools to attenuate rooftop noise
The aim of this research is to investigate the viability of designing urban rooftop soundscapes. The prerequisite is to reduce the sound propagation from road traffic by introducing living architectural rooftops with various components of sound attenuating technologies. The final goal is to turn unused rooftop space into a livable urban green space, where soundscape is balanced, and sound energy is reduced to the limits recommended by the World Health Organization (WHO). The first part of this research is to identify the potential of living architectural technologies to attenuate noise from road traffic. More than 33 measurements are performed of living architecture design tools, such as green roofs, berms at edge, living wall barriers and overhangs, to investigate the behavior of sound attenuation in an anechoic chamber and in ODEON, a computer simulation software. The second part of this research is to use the findings on the proposed design tools for an architectural case study, a flat-roof five-storey building located on East Hastings Street. The use of a combination of green roof, berm, overhang, guard and living wall can reduced urban traffic noise from 70 dBA on the roof to 55 dBA, creating additional acoustically healthy habitable space in the urban environment.
Experimental investigation of residential building heating and ventilation systems performance
The building sector is one of the most dynamically evolving field with an expectation to provide comfortable, clean and healthy indoor environment with less energy consumption. This acceptable indoor condition is created with a combination of heating/cooling systems and ventilation strategies. There are various systems available, which can deliver heating/cooling as well as ventilation to a dwelling space. These systems involve different heat transfer mechanisms and ventilation strategies: as a result, their performance would be different. Accordingly, the performance of these systems would affect indoor conditions. The process of providing an acceptable indoor environment with minimized energy use can be challenging. In addition to that, there is also a keen interest to reduce the current trend of the building energy consumption as low as possible without affecting the required, comfortable indoor environment. Therefore, the requirement of comprehensive field research that studies and compares most of currently available space heating systems, as well as ventilation strategies, is highly vital to provide information about their actual and relative performance in a real scenario. This research project conducts a field experiment that studies, heating systems, ventilation strategies, and ventilation flow rates. The first part is done by running two different heating systems at a time out of four heating systems (electrical baseboard heater, portable radiator heater, heat pump, and Radiant floor heating systems) in identical full-scale test building with similar ventilation strategy and similar ventilation flow rate. Whereas, the second group of experiments compare two ventilation strategies (mixed ventilation and underfloor ventilation) inside two test buildings with similar heating systems and ventilation flow rate. The third group of comparison compares three ventilation flow rates (15 cfm, 7.5 cfm, and 5 cfm) in the test buildings with similar heating systems and ventilation strategies. Various indicators and indoor environmental elements are used to conduct the comparisons. In the first case where heating systems are compared, the thermal energy provide by the systems are used for comparison. In addition, the thermal comfort, local thermal discomfort, temperature distribution and RH distribution are used to assess and compare the indoor environment produced by the systems. Whereas, the ventilation strategies are compared using indoor environmental element (temperature, relative humidity, CO2, and air velocity) distributions. Finally, the comparison of ventilation flow rates is performed using contaminant removal effectiveness, indoor air quality number, and indoor environmental element distributions. The findings from the experiments indicate that all of the heating systems provide similar daily thermal energy between 10 kWh and 14 kWh based on the outdoor weather condition. In addition, all of the heating systems produce a thermally comfortable indoor environment for standing person. Whereas, the ventilation strategies comparison shows that mixed ventilation strategy performance is slightly better than an underfloor Ventilation strategy by creating marginally uniform CO2 and RH distribution. Moreover, the results of the ventilation flow rates comparison show that the temperature and air velocity distribution find similar while using all the three ventilation flow rates. But the higher ventilation flow rate removes relatively more RH and CO2 in comparison to the lower one. Accordingly, the higher ventilation flow rates depict higher contaminant removal rate and high indoor air quality number relative to lower ventilation flow rate., Ventilation Effectiveness, Ventilation Flow Rate, Indoor Air Quality Number, Thermal Energy, Portable Radiator Heater

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