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

BCIT Thesis and other Required Graduate Degree Works

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Field experiment on the effect of interior living walls on indoor environmental quality
Indoor environmental quality (IEQ) has multiple aspects such as: indoor air quality (IAQ), acoustics, thermal conditions, lighting, and ventilation. This research focuses on indoor air quality and acoustics and studies the effect of interior living walls on indoor air quality and acoustical characteristics of rooms through field monitoring and experiment. Previous laboratory studies have been carried out at the British Columbia Institute of Technology (BCIT) and the University of British Columbia (UBC) on the effect of living walls on acoustics and indoor air quality. This study, examines the acoustical effect of living walls (background noise level, reverberation time, and speech articulation) as well as the effect of living walls on indoor air quality (Carbon Dioxide, Volatile Organic Compound, and endotoxin) through field measurements in the BC Hydro Theater at the Centre for Interactive Research in Sustainability (CIRS) at UBC. Existing predictive models are verified using field data, and are used to predict the effect of interior living walls on indoor air quality and acoustics in an adjoining lab., Interior living walls
Field investigation of moisture buffering potential of gypsum board in a residential setting under varying operating conditions in a marine climate
Indoor relative humidity is of critical importance to maintain at acceptable and stable levels for building occupants’ health and comfort, energy efficiency, and building envelope durability. The main factors that determine the indoor relative humidity levels in a building are ventilation rate and scheme, moisture sources and sinks, and moisture buffering effect of materials. As buildings enclosures are retrofitted for improvements in water shedding and energy performance, they are becoming more airtight. Such a retrofit measure without addressing increased ventilation needs will lead to significant building envelope and indoor air quality problems. In this thesis, this point is highlighted in a reference residential building, occupied by low-income, high occupancy residents. This research aims to determine the effect of moisture buffering of unfinished gypsum board as a passive means to regulate indoor humidity in a field experiment setting. Two identical test buildings exposed to real climatic loads are used to evaluate the moisture buffering effect of gypsum board for different simulated occupant densities and ventilation strategies. The effect of passive and active indoor moisture management measures are compared between 8 test cases. Implications on indoor air quality and ventilation heat loss are also discussed. The results show that moisture buffering is an effective means of passively regulating indoor relative humidity levels in Vancouver’s marine climate, when coupled with adequate ventilation as recommended by ASHRAE, even under high moisture loading. When working in tandem with adequate ventilation, moisture buffering helps to regulate changes in relative humidity levels by reducing humidity peaks. This in effect decreases dew point temperatures, and the likelihood of condensation and microbial growth. 4 ventilation schemes are provided as active measures to manage indoor moisture coupled with moisture buffering in the field experiment. The results show competing benefits when it comes to managing indoor air quality, indoor humidity, and minimizing ventilation heat loss. Time-controlled ventilation is effective at maintaining relative humidity at acceptable levels for thermal comfort. Time-controlled ventilation also provides considerable savings in ventilation heat losses of 20% in comparison to constant ventilation. However, CO2 levels are exceeded beyond what is acceptable for good indoor air quality for 50% of the monitoring period. Conversely, demand-controlled ventilation schemes produce favourable indoor air quality based on CO2 levels, while compromising indoor humidity levels.
A field study on quality of three First Nation homes on the Squamish Urban Reserve of West Vancouver
Three new homes in the First Nations Squamish urban reserve were instrumented, tested, and monitored for a period of one year. Performance data was obtained from these homes and analyzed to help assess their quality and improve their performance. From the field study, the houses performed reasonably well. However, there is large room for improvements. Considering construction durability, the built-in moisture in the houses dried well. However, as expected, the moisture in the attics was high and improvements are recommended. The monitoring also confirmed that north facing walls take more time to dry and remain wet in some areas, despite the fact that the monitored year was one of the driest years in record, as reported by Environment Canada. Dangerously high moisture levels were also recorded in a few wall locations, believed to be caused by construction deficiencies at window sills and wall penetrations. In general, wall orientation and obstructions to solar radiation play a major role in the moisture balance of walls. This study confirmed that north-facing walls have higher moisture content, which also takes longer to dry out. South-facing and east-facing walls have lower moisture content (i.e. due to higher solar radiation and higher wall temperature to promote evaporation). The effect of external obstructions (i.e. large trees) to solar radiation was seen in the high moisture content of the west walls that was close to that of north walls. However, as reported in this study, poor construction detailing overpowers orientation on impacting wall moisture, and is the major source of concern for rain penetration. Unfortunately, wood-frame construction is unforgiving to construction deficiencies, and maximum care must be exercised to protect all details and wall penetrations from rain. Considering the indoor environment, in general the conditions were within acceptable limits; however, indoor conditions are greatly affected by occupants’ behaviours (e.g. opening windows in cold days). Particular problems arising from tobacco smoking and wood carving could not be measured. From the field study and computer simulations, it is recommended to make the houses more airtight to improve durability, energy efficiency, and possibly indoor air quality. It is also recommended to decouple the ventilation system from the house heating system to improve its ventilation reliability., Monitoring First Nation homes, Indoor air quality and energy efficiency, CO2 contaminant dispersion models, Ventilation
Geochemical and biological response of an intertidal ecosystem to localized restoration efforts
Geochemical and biological attributes of three intertidal areas in the Squamish Estuary with different levels of disturbance (low, medium, and high) were assessed to determine short-­term ecosystem responses to localized restoration efforts conducted one year previously on a former log handing site. Sediment and macroinvertebrate variables were analyzed among sites to characterize the ecosystems response and provide insight on the nature and process of an assisted successional trajectory. Invertebrate composition and biomass were lowest on the site with the highest level of disturbance. The high disturbance site also contained the highest percentage of fine sand (0.0067 mm to 0.25 mm). This confirms that in the short term there are distinct site responses to disturbance and ameliorative restoration efforts – even in a highly dynamic estuarine environment. The medium site contained more invertebrates than the low disturbance site indicating that something other than localized disturbance is affecting the invertebrate community on the low site. All sites exhibited a less-­rich and less diverse invertebrate community than that of historical records (circa. 1970-­1980). Invertebrate community in the east delta today is more typical of estuarine environments with higher salinity levels -­ which indicates more widespread levels of disturbance throughout the Estuary is affecting the study sites. This study highlights the importance of considering temporal and spatial scales when setting restoration goals, objectives and creating monitoring plans. Additional monitoring of sediment, invertebrate, and other variables on restored and reference sites is recommended to characterize typical recolonization and reassembly attributes of restoring intertidal estuaries in coastal British Columbia. This would provide evidence and rigor in determining effective restoration techniques and management strategies for a critical and increasingly threatened ecosystem., Macroinvertebrates, Restoration, Sediment, Benthic ecology, Estuaries, Intertidal flats
Hygrothermal performance of super-insulated double-stud wood frame wall assemblies
In cold climates, much of wood-frame building enclosure durability failures and indoor air quality issues stem mainly from excessive moisture within enclosure components and these issues are more pronounced in buildings with higher levels of thermal insulation, with frequent mold and fungal growth complications. Nevertheless, buildings have been increasing their insulation levels (and this trend is expected to continue) due to climate change, depleting natural resources, ever-rising energy prices and growing expectation for occupants’ comfort and health. Incorporation of insulation materials with higher moisture storage and buffering capacities and also employing vapour retarders that can let walls dry out to both interior and exterior spaces are potential solutions. While the hygrothermal behaviour of these insulation materials have been extensively tested in material labs and computer modeling projects, their actual performance in different climatic zones demands more field experimental studies. In this study, a field experiment was designed to assess hygrothermal behaviors of five highly insulated test wall panels under Marine climatic zone of, Burnaby, British Columbia. Full size wall panel specimens of ‘double-stud’ wood-frame were instrumented with moisture and temperature sensors and filled with Dense Cellulose Insulation (DCI) and Low-Density Spray Polyurethane Foam Insulation (LD SPFI) under different vapour control layer scenarios of 4-mil Polyethylene film, Smart Vapour Retarder (SVR), and none. All test panels were exposed to the 4 controlled indoor and the actual outdoor climates and their hygrothermal response was recorded and analysed from 01 Sept 2016 to 31 May 2017. The experimental results suggested DCI is a proper insulation material provided that it is equipped with a dedicated interior vapour barrier. The results also suggested while both DCI had LD SPF had acceptable moisture behaviour; DCI had slightly better performance than LD SPF. As for vapour control strategies, Smart Vapour Retarder (SVR) did not show an obvious advantage over 4-mil Polyethylene film and in some cases was slightly outperformed by polyethylene hygrothermally. As a general comment, the exterior sheathing board, plywood had the highest moisture activity and all other components, mainly the exterior and interior studs and plates remained in safe moisture ranges throughout the test period., Insulation, Dense Cellulose Insulation, Low-Density Spray Polyurethane Foam Insulation, Hygrothermal performance
Hygrothermal propertied of building materials at different temperatures and relative humidities
This research project investigated and measured a set of hygrothermal characteristics of several building materials commonly used across the North America. This study examined the behavior of building materials under various climate conditions other than what is proposed by the standards. Improving available standard test methods by using state-of-the-art equipment, enabled me to measure thermal conductivity, sorption isotherms, water vapor permeability and water absorption coefficient of tested materials under nine different combinations of temperatures from iv 3°C to 45°C and relative humidities from 50% to 90%. The results clearly present dependency of material properties on varying temperature and relative humidity. For example, thermal conductivity, vapor permeability and water absorption coefficients of all tested materials increased with respect to temperature, while the sorption isotherms of all materials decreased when temperature rose. The obtained results from this research can be utilized in Heat, Air and Moisture (HAM) modeling to improve effective and realistic analysis hygrothermal and energy performance of whole buildings.
Identifying temporal trends and mechanisms for successful reforestation on former agricultural land
This study investigates the outcomes of restoration efforts completed on retired agricultural land in Southwest Ontario. Sites acquired by the Nature Conservancy of Canada were planted to kickstart succession to native deciduous forests, but the results of the plantings are mixed. Analysis of soil conditions indicated that low levels of soil organic carbon were correlated to low water content and high density unfavourable for plant growth. Analysis of remotely sensed imagery was done to assess and compare vegetation cover to reference conditions at Walpole Island First Nation. Analysis revealed that successful restoration was dependent on multiple soil characteristics, but conditions correlated to higher total organic carbon favoured greater vegetation cover. Remote sensing data revealed that succession towards tree canopy development was accelerated compared to passive restoration, and a shaded understory was established approximately 8-12 years following restoration. Future work can expand on succession and the effects of other restoration treatments., Soil, Reforestation, NDVI, Agriculture, Restoration, Secondary succession
Investigating regeneration in a raised ombrotrophic bog after peat extraction
Burns Bog is a raised ombrotrophic bog in Delta, British Columbia and faced with myriad disturbances. This study is focused on the impact and restoration of peat extraction by the Atkins-Durbrow Hydropeat method. Depth to water table, relative abundance and distribution of vegetation, and the degree of peat decomposition at consistent-depth intervals were investigated to elucidate the status of passive and active ecological restoration in three fields previously harvested for peat approximately one decade apart and compared to a fourth unharvested field. Summary statistics, Redundancy Analysis, and regression were used to compare restoration status and trends in hydrology, vegetation composition, and peat accumulation. A lag period between cessation of harvest and implementation of restoration, coupled with rapid anthropogenic climate change, serve as impediments to restoration here. Intervention in the form of improved rainfall retention, assisted recolonization, and the introduction of nurse species are recommended to improve bog function and resiliency., Atkins-Durbrow Hydropeat method, Ditch blocking, Ecological restoration, Peat extraction, Raised ombrotrophic bog, Burns Bog
Investigating the role of elevated salinity in the recession of a large brackish marsh in the Fraser River estuary
At least 160 ha of the Sturgeon Bank low marsh in the Fraser River delta died off between 1989 and 2011. Humans have heavily modified the Fraser River estuary since the late 1800’s, including installing a series of jetties throughout the leading edge of the delta to train the course of the river. I established a reciprocal transplant experiment to determine the role of elevated salinity in the marsh recession and generate information needed to eventually revegetate areas of receded marsh as part of an intergovernmental collaboration to investigate the causes of this marsh recession. I propose specific actions to better monitor, maintain, and restore the Fraser River delta foreshore brackish marshes in response to ongoing ecological degradation of the estuary. The predicted effects of climate change and sea-level rise may cause us to rethink options for restoring the Sturgeon Bank marsh., Restoration, Fraser River, Schoenoplectus pungens, Reciprocal transplant experiment, Marsh recession, Brackish marsh
Model-based coupling of air and hydronic system operation in a high performance academic building
This research is motivated from preliminary teamwork on analyzing the “Performance Gap” of three high-performance buildings, which are currently under operation. All three buildings are facing operational challenges that are not unusual considering the complexity of their systems. However, evidence from design documents, an existing energy model, and operational data suggests that their performance is not entirely reflecting the design intent. This research follows the premise that there is a need to design buildings as systems-of-systems to be able to understand, interpret, quantify, design, and fine-tune the dynamic couplings between systems. This research was dedicated to a high-performance academic building (HPAB) – one of the above three buildings – as a case-study to gain understanding on the complexities of systems coupling, and learn and apply dynamic simulation-based systems coupling tools and methods. The main focus of the study is the classrooms because of the existing evidence on the significant impact of indoor environmental comfort on student performance in academic facilities. The HPAB case-study building incorporates, at the source side, ground-coupled water-to-water heat pumps (WWHP) and solar-thermal as primary means of heating, with boiler used as a backup source. Cooling is provided by the cold side of the WWHP system. On the demand side, heating and cooling are delivered via thermally active radiant floors; while air handling systems take care of the ventilation and de/humidification needs, and provide supplementary heating and cooling. The building was initially designed to rely on natural ventilation for summer cooling; however, designers realized that natural ventilation alone was not able to meet the building cooling demands in the summer. Nevertheless, the building has operable windows and a central atrium that seems to be collecting the air from the individual spaces and exhausting it after some heat recovery. The thermally active building is not adequately meeting the demands from some critical zones. Furthermore, the operation is not consistent with the reduced hours of summer operation of an academic building. These and other observations on the building indicate that the air and radiant systems are not operating in synergy. Existing industry practices in building controls systems, and the research literature show limited evidence of efforts to attempt to harmonize these two complementary systems. Simulation was used to re-create the HPAB building’s mechanical system response in two levels: a classroom-level model, and a Whole Building Energy Model (WBEM). The implementation was in EnergyPlus modeling software. Design documents, and historic operational data from the building automation system (BAS) were used for calibration. In this work, various features of Energy Management System (EMS) module of EnergyPlus has been utilized to create a responsive mechanical system control within the simulation. In the end, the typical responses of the building spaces could be accurately recreated in the simulation for both models. In the next step, testing different controls approaches – labelled as Strategies – and comparing them with defined comfort and stability metrics showed that harmonizing the air and radiant systems, in addition to increasing the consistency of the radiant system operation, results in improvement to the system operation without sacrificing the comfort. This research explores the challenges of employing a WBEM to assist building design decisions by accounting for the building dynamics and enabling the coupling and tuning of systems parameters and control strategies through simulation. The research demonstrates the benefits of improved operational control sequences that are more in tune with the building’s design intent.
Multi-objective optimization of high performance residential buildings using a genetic algorithm
Traditional methods of design and construction of residential buildings are common practice, and in most cases, are required by building codes. However, these design practices do not necessarily yield the most optimized designs in terms of cost, environmental impact, and occupant thermal comfort. Typically, the owner or investor hires an architect that designs the building based on the client’s requirements, and then technical designs, such as enclosure and HVAC systems, are tasked to construction and mechanical engineers to satisfy the original design without consideration to energy consumption and environmental impacts. Those who are energy and environmentally conscious rely on an iterative trial and error method using energy simulation tools, and this method consumes much time and resources. To address this problem, this research presents the development and implementation of a simulation-based optimization tool that relies on a genetic algorithm to systematically improve the building design at a conceptual stage based on a set of objective functions. For the purpose of this research, the objective functions include the life-cycle costs, life-cycle global warming potential, and occupant thermal comfort. More specifically, occupant thermal comfort (measured in PPD) acts that the constraint objective. In this study, a multi-objective optimization genetic algorithm was implemented to find optimal residential building enclosure assemblies that minimizes the life-cycle costs, life-cycle global warming potential, and keeps occupant thermal comfort within check. Based on the design variables and objective functions, a software tool consisting of four modules is used for optimization: the input and input parameter database files; the genetic algorithm optimization software (jEPlus+EA); the energy simulation program (EnergyPlus) and the optimized output files. All required software and simulation programs can be acquired free of charge from the internet, with the exception of proprietary database files such as material and construction assembly libraries. For validation, the optimization tool is implemented on a benchmark study, which demonstrates its application and capabilities. The benchmark study is based on ANSI/ASHRAE Standard 140-2001 BESTEST calibration and validation test case 600. The optimization results in multiple Pareto optimal solutions that gives the user a detailed look at the trade-off between the objective functions when high performance building systems are used. The optimization tool is then applied to a case study where an actual single family home (Harmony House) is modeled and important building design parameters are identified and discussed., Multi-objective building optimization, Life Cycle Cost Analysis (LCCA), Life Cycle Environmental Assessment (LCEA), Green buildings, Building assessment methods
Performance evaluation of active chilled beam in cooling and heating operation under actual field boundary conditions
People spend most of their time indoors and often share the same environment; therefore, knowledge and prediction of the indoor conditions are important to optimize the indoor conditions for the occupants at the building design phase. A range of parameters like air velocity, temperature and relative humidity determines the indoor climate and are important for the comfort of the occupant of a room in terms of thermal comfort and indoor air quality. Active Chilled Beam (ACB), a high-performance air distribution system has gained popularity as an energy efficient, sustainable comfort cooling technology with favourable performance in term of thermal comfort to occupants. ACB is wildly utilized in a variety of commercial buildings, schools, laboratories and hospitals. However, in-depth investigations on the performance of these systems under different boundary conditions are still inadequate., Active chilled beam, ACB under cooling, ACB under heating, CFD, Room airflow, Ventilation efficiency

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