Research
Shaping future sustainable neighborhoods
Optimal design of mixed-use neighborhood
In a mixed-use neighborhood, the understanding the effect of various building types and other community design parameters (i.e., building density, commercial area fraction, etc.) on the performance of neighborhood is extremely important. For instance, it is presented that how the ratio of performance (RoP) got affected with the changing fraction of various housing types such as single detached (SD), townhouse (TH) and apartments (AP).
The similar results can be obtained for other crucial performance parameter such as energy consumption, PV generation, waste-to-energy (WtE) generation, and GHG emissions. The extended objective of this research to get the optimal mixture of residential and commercial buildings along with optimal values of other neighborhood design criteria. One of the key conclusions of the optimal value of commercial to residential land fraction is between 0.23 and 0.32. Further, using proposed generalized optimization methodology, multiple combinations of various buildings can be yielded.
WtE-CHP analysis for mixed-use neighborhood
In the designing of sustainable neighborhoods, the planning of alternative energy resources (RES) plays a vital role, which is one of the focus areas of SDECL. The quantification of WtE-CHP output with the variation in neighborhood design parameters accounting the waste disposal of neighborhood is carried out under this research. The layout of WtE-CHP plant and its integration with mixed-use neighborhood load can be visualized in figure. The finding from this research reflects that the usage of single or two stage CHP plants is governed by the waste generation from commercial sector. Keeping optimal commercial land fraction as 0.25 (found in above research), the two stage CHP plant can be used within the neighborhood for all possible combinations of residential buildings.
Resilient sustainable neighborhoods
In the planning of sustainable neighborhoods, adding the perspective of disaster resilience shapes the research in a unique way. In SECDL, nevertheless this is one of the verticals under the diverse research interest. Both solar access and resilience are studied under this interest for three neighborhood layouts such as square, circular, and hexagonal. In figure, it can be seen that how the solar access varies in various neighborhood layouts on various days in year in different seasons.
Further, the centrality and connectivity parameters are found extremely useful in analyzing the resilience of neighborhood street network for various layouts. For example, in figure below the distribution of betweenness centrality can be visualized for various neighborhood layouts.
Design of energy resources
In SDECL, we are actively working on the development of generalized algorithm for the optimal planning of renewable and alternative energy systems (RES and AES) within mixed use neighborhoods. This research involves various objectives such as attainment of self energy sufficient neighborhood, net-zero energy neighborhood, energy positive neighborhood, revenue generating neighborhood towards the RES and AES capital costs, and net zero-carbon neighborhoods. In future, this research may play key role as benchmark tool for policy makers and planners.
Design of multifunctional façades
High-rise buildings provide a significant solution to the housing situation that cities face due to rapid urban growth. Additional benefits associated with high rise multi-storey buildings include reduced land use and increased energy efficiency as compared to single-family houses. The related issue with this intense densification is high energy demands. A substantial solution to this is Net-Zero Energy (NZE) high-rise buildings.
The concept of NZE buildings provides a strategy to improve buildings energy performance while producing as much energy as consumed from renewable resources, over a year. However, the challenge of achieving NZE in high-rise mixed-use buildings is to find efficient and aesthetic solutions to integrate solar technologies.
Multifunctional façade modules (MFM) offer the potential for integrating energy generation systems with buildings envelopes. The main objective of these modules is to provide indoor thermal comfort and adequate daylighting while generating energy. However, balancing these functions is a process that required from studying multiple design strategies.
The focus of this research is to investigate these designs to develop MFM capable of improving high-rise mixed-use buildings energy performance to achieve NZE. Different combinations of elements, such as new materials and technologies, as well as orientations and shapes, will be investigated. To observe the performance of the obtained designs, two NZE communities in Canada and Mexico (work support by Mitacs through the Mitacs Accelerate Program) will serve as a case study for the analysis.
Current status of this research shows the potential for improving energy generation through PV systems in façade-integrated MFM. As observed in the image above, facades in cold places have better solar radiation during summer months than hot regions. However, a study varying tilt angles of PV modules prove that energy output can increase if following designs such as folded-plates or sawtooth elements. Future work will be to design, model, and simulate several types of MFM modules under the case study examples.
Building energy sharing
The global projection of urban growth and increasing population densification creates new opportunities for an expanded role of greenhouse technology. Coupling a greenhouse with supermarket, as a method for energy sharing, has been identified as a promising method to increasing efficiency of the building operations while reducing dependency on transportation.
The results show that with an integrated building design approach, cutting edge technologies and high energy efficiency measures a net reduction of 27% energy in the greenhouse-retail complex is achieved compared to design complying with the minimum requirement of the applicable energy codes. Additionally, by sharing waste heat recovered from retail refrigeration compressor racks, 21% of space and ventilation heating demand of the greenhouse and energy demand for irrigation water and service hot water for the complex can be met. Employing on-site renewable energy generation, net-zero energy performance of the greenhouse-retail complex can be achieved. It has been found that by feasible combination of buildings optimized to harness on-site energy and sharing energy between the individual buildings, dependence on utility grids can be reduced, in addition to having a local source of food growth for climate change resilient urban infrastructure.
Figure represents a Sankey diagram demonstrating the energy flow between the recovered compressor rejected heat that is shared with the adjacent greenhouse. A total of 130 MWh (470 GJ) of waste heat is recovered from the retail compressor rack. Since no thermal energy is stored on site, the waste heat recovered can only be share within the Complex in the real time. However, graph below shows the monthly heating energy sharing between the retail and greenhouse. Heat captured from the compressor rack is shared with the greenhouse to provide space heating, irrigation water heating and ventilation air heating for the greenhouse.
Net-positive and nearly zero carbon residential neighborhoods
Achieving Net-Zero Building status is quite expensive & reduction in utility cost is covered by an increase in the mortgage. So, to make this Net-Zero concept more practical there is a need for leveraging the scale. This leads to incorporation of many variables & best design resides in identifying the optimal value of each variable with respect to other ones. Studies show practical ways to incorporate the certain aspects that lead neighbourhood towards net-zero status like Master Planning guidelines, improving economic drivers & district design principles.
Current research work revolves around evaluating 252 high-energy performance residential neighbourhood designs which are capable of achieving net-positive energy status i.e. combined on-site energy offsets energy consumption aspects and nearly zero carbon emissions. In other words, developing communities with the best of urban living & best of suburban living.
Results: The simulation results revealed that optimization at the building level could reduce the impact of neighborhood site layout by 46.2 – 51.4% and building shape can enhance net-positive energy (NPE) status by 8-10%. The best neighborhood design achieved a 13.9% net-positive energy status and diminished carbon emissions by 95%.
Energy performance and lifecycle environmental assessment
Our research aims to assess the energy performance and the environmental damages and impacts of Magnesium Oxychloride Cement (MOC) wall panels produced in Alberta using the energy modelling and Life Cycle Assessment (LCA) approach. First, we evaluate the environmental damages and problems of MgO and Portland Cement Production in Alberta. To have a comprehensive assessment and comparison of environmental problems, the LCA of MOC wall panels are compared with concrete-based and wooden-based wall panels. Also, the energy performance of the panels is evaluated and innovations have been developed to achieve high-performance building envelope walls. Figures show the high-performance senarios, research steps and an example of damage assessment.
Waste reuse in high performance building envelopes
The LCA methodology is used to examine the embodied impacts of waste materials reused in the building envelope. The goal of the analysis is to examine the degree to which each recycled material may, in part or in whole, reduce the burden of virgin construction materials. End of life tires, plastic polyethylene terephthalate (PET) bottles and paper and cardboard wastes are examined in various parts and functions of the envelope (thermal mass, insulation, wall, and ceiling boards) to create different envelope configurations. Using a functional unit of a detached two-storey house in Calgary and a system boundary focused on the pre-use phase from extraction to transportation to site, the four designs using waste materials are compared against a base case designed to exceed the energy efficiency of the national building code using conventional construction materials such as concrete block and slabs, brick facing and polystyrene insulation.
Open LCA is chosen for its flexibility in specifying material processes and flows, an important factor where non-conventional construction materials are used. The method of handling recycled credits used is the closed loop method, in which all burdens of production are attributed to the first life cycle of the material. Therefore, for end of life wastes applied in the envelope, initial production burdens of the tires, PET bottles and papers are excluded from the model which focuses exclusively on envelope application. Material production, recovery and recycling methods in the life cycle inventory are gathered from relevant literature and databases such as those of the Athena Sustainable Materials Institute.
The TRACI impact calculation method by US Environmental Protection Agency is includes the most geographically relevant impact categories for North America including: acidification potential (elements) (AP) in kgSO2eq, carcinogenics (fossil fuels) (HTPc) in CTUh, ecotoxicity potential (ETP) in CTUe, eutrophication potential (EP) in kgNeq, fossil fuel depletion potential (FFDP) in MJ surplus, global warming potential (GWP) measured in kgC2Oeq, non-carcinogenics (HTPnc) in CTUh, ozone layer depletion potential (ODP) in kgCFC-11eq, respiratory effects (RE) in kgPM2.5eq, smog formation potential (STP) in kgO3eq. The analysis demonstrates reductions of about 70-80% for most impact categories in the design cases, within margins of 1-5% of one another while smog formation tends towards a 65-70% reduction (Figure 3). The use of cellulose fibre insulation in Designs 1, 2 and 4 leads to an 80% increase in fossil fuel depletion potential from the base case and Design 3.
