Hourly dynamic energy performance study of buildings requires an in-depth understanding of dynamic thermal performance of building envelope assemblies. While two and three-dimensional building envelope thermal bridges have a great impact on whole-building energy simulations, heat storage capacity of the layers has also a significant influence. State of the art research has confirmed necessity of accurate thermal storage behavior analysis of building envelope assemblies in dynamic hourly building energy simulations. To-date, a number of studies have been conducted on the simplification of transient behaviour prediction of one, two and three-dimensional building envelope assemblies.
In this study, the previous equivalent and simplified models for prediction of dynamic behaviour of building enclosure are reviewed, and an improved equivalent model based on frequency responses of RC-Network (FR-RCN) is presented. The model utilizes thermal RC-Network with three unknown resistances, two known resistances, and four unknown capacitances. The frequency responses of building envelope assembly are calculated either analytically (one dimensional assemblies), or numerically using COMSOL (two/three dimensional assemblies). Eureqa, a software which leverages evolutionary algorithms, is utilized in order to generate optimized unknown RC-Network resistances and capacitances considering the calculated frequency responses of the assembly. In this study, one light weight single-family home, one mass type structure high-rise building, and selected steel construction assemblies in climate zones 2 and 6 have been considered. A simple approach is also presented for the generation of equivalent FR-RCN models of variable insulation thickness assemblies. The comparison between the transient results calculated from the equivalent FR-RCN and COMSOL simulation shows good agreement. The performance of FR-RCN method is compared with other selected equivalent models, and an improvement in accuracy is confirmed., RC-Network, Multi-dimensional assemblies
Forest managers are interested in determining how stands that have been logged might be managed to restore features characteristic of forests in later-stages of development. Incorporating forest restoration into forest management enables the use of forest-management skills, such as silviculture and regeneration techniques, to manage individual stands for multiple objectives. Therefore, I performed a comparative analysis of large trees, very-large trees, large snags, very-large snags, and large CWD among three stand types (i.e., 60-yr-managed, 140-yr-natural, and 500-yr-natural stands). The 140-yr-natural and 500-yr-natural stands were used as reference conditions to guide the restoration of a 59-yr-managed spacing trial. All attributes differed among stand-types; however, large snags were the most similar attribute between 140-yr-natural and 500-yr-natural stands. Large trees were the fastest attribute to recover in 60-yr-managed stands, however mean values among stand-types still differed. This study highlights the potential of restoring old-natural attributes in younger-managed stands to increase ecological resiliency., forest, natural, managed, prescription, restoration, old-natural attributes
Laneway housing is an innovative higher density housing form introduced to meet the City of Vancouver’s EcoDensity Charter. This form of residential occupancy was introduced without specific acoustical standards for construction. Noise concerns generally accompany increasing urban density, particularly in housing located close to transportation and activity centers. Laneways and laneway housing have environmental and architectural features that can contribute to noise levels exceeding criteria for healthy living. To advance the state of practice, this research first explores the sonic environment of laneways, including sound propagation, urban canyon effects, and sound sources. Second, this research investigates the acoustics of the laneway house, including outdoor-indoor sound insulation of facades, architectural features, and floor plan layout in relation to environmental noise sources. Empirical field measurements, the CMHC road traffic noise model and software modelling programs are used to investigate the acoustical environmental quality of laneway housing. Findings from case study investigation of four laneways and six laneway houses are evaluated against the CMHC noise criteria for healthy living. The various research tools are evaluated for accuracy and practicality as acoustic design tools for Vancouver laneways and laneway housing. The results of this study can inform laneway development planning (including benefits of laneway vegetation), laneway house design, building envelope construction, and policy guidelines as the City of Vancouver continues in its plans for sustainable densification., Acoustics of small buildings, Urban canyon effect, Road traffic noise, Laneway house acoustics
Exterior building envelope walls with rainscreen cavities are now required by British Columbia building codes. The introduction of the rainscreen cavity and optional external thermal insulation can alter sound transmission loss and consequently affect indoor sound levels in single and multi-family wood-frame housing. In this study, 57 exterior wall assemblies were built and acoustically evaluated using a hybrid sound intensity technique. The variables investigated were cladding material (vinyl, fibre cement board, and stucco), exterior insulation (mineral wool and XPS), exterior insulation thickness (1 ½" and 3"), cladding attachment type (resilient and non-resilient), and rainscreen cavity width (3/8" and 1"). The sound transmission class of the tested wall assemblies ranged from 37 to 52; the outdoor-indoor transmission class rating ranged from 26 to 37. Results indicated that the selection and the combination of the material layers were fundamental to sound transmission loss performance. Cladding material and cladding attachments influenced sound transmission and resulted in a broad range of overall performance. The split insulated rainscreen cavity wall assemblies presented higher transmission loss than single insulation walls, provided that the exterior insulation had sound absorbing properties. The best performing wall assemblies generally have high mass cladding, resilient cladding attachment, and 3" mineral wool exterior insulation (in addition to the interior cavity insulation). Given the research outcomes, in denser and noisier urban areas, a building envelope professional has additional options to design an exterior rainscreen cavity wall to meet thermal performance and acoustical criteria for exterior sound levels in wood frame buildings.
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
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
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.
