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This research presents a 3D geographic information systems (GIS) modeling approach at a fine spatiotemporal resolution to assess solar potential for the development of smart net-zero energy communities. It is important to be able to accurately identify the key areas on the facades and rooftops of buildings that receive maximum solar radiation, in order to prevent losses in solar gain due to obstructions from surrounding buildings and topographic features. A model was created in ArcGIS, in order to efficiently compute and iterate the hourly solar modeling and mapping process over a simulated year. The methodology was tested on a case study area located in southern Ontario, where two different 3D models of the site plan were analyzed. The accuracy of the work depends on the resolution and sky size of the input model. Future work is needed in order to create an efficient iterative function to speed the extraction process of the pixelated solar radiation data.

To date, the residential sector accounts for a major portion of consumption by consuming more than 40% of the entire world's energy and producing 33% of the carbon dioxide emissions. In North America, the residential sector energy consumptions are mainly related to heating, ventilation, and air conditioning (HVAC) systems, which are not operating in the most efficient ways due to existing on/off and conventional controllers. In Ontario, due to the variable price of electricity, variation in outdoor disturbances, and new Ontario Government sweeping mandate in overhauling the energy use in residential sector, there is an opportunity to develop intelligent control systems to employ energy conservation strategy planning model (ECSPM) in existing HVAC systems for reducing their operating cost, energy consumption, and GHG emission. In order to take advantage of these opportunities, two model-based predictive controllers (MPCs) were developed in this Ph.D. research. In the first MPC controller, a Matlab-TRNSYS co-simulator was developed to fill the lack of advanced controllers in building energy simulators. This cosimulator investigated the effectiveness of different novel ECSPMs on an HVAC system's energy cost saving during winter and summer seasons. This co-simulator offered 23.8% saving in the HVAC system's energy costs in the heating season. Regardless of the strong capabilities, employing this co-simulator for implementing comprehensive/complex optimization methods resulted in an unacceptably long optimization time due to the of TRNSYS simulation engine. Therefore, in the second PMC controller, simplified house thermal and HVAC system models were developed in Matlab. To design a grid-friendly house, this model was enhanced by integrating on-site renewable energy generation and storage systems. A novel algorithm was developed to reduce the MPC controller optimization time. The effectiveness of the novel MPC model in the HVAC system's energy cost saving was compared with a Simple Rule-based (SRB) controller, which itself is an efficient HVAC controller, while this controller offered 12.28% additional savings in the heating season.

Hybrid solar PV/T system control strategy plays an important role not only in PV/T system energy gain but also in the energy consumption of PV/T assisted heat pump systems. However, no research has been carried out regarding the effect of PV/T control strategy on the performance of PV/T assisted heat pump systems. It remains unknown how the key parameters of the PV/T system control strategies affect system performance, and it has not yet been established which PV/T system control strategy is better. To study the effects of the commonly used PV/T system control strategies on the performance of liquid-based PV/T assisted heat pumps, models of liquid-based PV/T assisted heat pumps with three different PV/T system control strategies were developed using combined platforms of EES and TRNSYS. Based on the models, the effects of the key parameters for each of these PV/T system control strategies on the PV/T system energy gain, overall energy consumption, average heat pump coefficient of performance (COP), and the overall system performance were presented, and the comparison of the three PV/T control strategies was performed. The results showed that a much larger PV/T pump size was needed for the outlet temperature control strategy to achieve a roughly equivalent performance to the other two control strategies.

Water and solid waste benchmarking and developing meaningful performance indicators can help government and building owners to make effective decisions on improving their buildings’ efficiency and sustainability. For this study, information on 120 multi-unit residential buildings (MURBs) has been collected and analyzed. The study entails the following steps: performing water and solid waste benchmarking for the 120 MURBs, developing meaningful performance indicators; determining performance ranking; and estimating different levels of savings (water, solid waste, cost, and GHG emissions). The most appropriate performance indicator and the benchmarking range for water and solid waste are as follows: water consumption normalized by square metre, 1.06–4.19 m3/m2; solid waste benchmarking normalized by number of units, 1.58–17.4 yd3/unit. Also, the MURBs domestic hot water system efficiencies are found to be very low (with overall system efficiency in the range of 35% to 45%). A relatively strong correlation is found between annual natural gas consumption and annual water consumption.

The indirect-expansion solar assisted heat pump (SAHP) is one of the main configurations for SAHP systems. Previous work on this configuration has focused only on one-stage heat pump cycles using traditional refrigerants, which will be phased out in the future. In addition, one-stage heat pumps may not work properly in cold climate regions. To evaluate the performance and understand the potential of indirect-expansion SAHPs using CO2 as a refrigerant for space heating in cold climates, models of an indirect-expansion SAHP with a one-stage transcritical CO2 cycle, with a two-stage transcritical CO2 cycle, and with the presently popular one-stage R410a cycle for space heating in Toronto, Canada were developed using the combined platforms of EES and TRNSYS. Based on these models, the performance variations of the three systems with solar thermal collector area, storage tank volume, and heat pump compressor capacity were simulated, compared, and presented. The comparison of the systems showed that the performance of the two-stage cycle peaked at a much smaller compressor capacity than that of the other cycles – 0.4 m3/h for the two-stage cycle, 0.7 m3/h for the one-stage cycle, and 1.7 m3/h for the R410a cycle. When the three systems operated at the optimal compressor capacity, the free energy ratio (FER) of the two-stage cycle could reach 0.772, which was higher than that of the one-stage cycle by 19.0% and higher than that of the R410a cycle by 11.6% at the given conditions. The potential cost reduction benefits from the smaller compressor and higher FER could make the two-stage cycle more competitive than the other cycles in cold climates.

An eQUEST model was developed to conduct a simulation study of a natural gas engine-driven heat pump (GEHP) for an office building in Woodstock, Ontario, Canada. Prior to the installation of the GE...

This paper presents the analysis, simulation and performance study of heat transfer in a single U-tube borehole heat exchanger (BHE). Unsteady heat transfer method was used to analyze the heat transfer process of both inside and outside the borehole. Implicit numerical method applied on heat transfer equations obtained from energy balance (accompanied with thermal resistance model) was used to obtain the solution. The variation of mean fluid temperature, average borehole wall, grout and nearby ground temperature as well as borehole loading with borehole depth and time were investigated. Dynamic simulation was also performed to assess the influence of important parameters. The effect of two parameters, fluid mass flowrate and thermal conductivity of grout, on mean fluid temperature, borehole wall, grout and ground temperature as well as on borehole loading and borehole thermal effectiveness were investigated. The outcome of this study can substantially reduce the time devoted for research and to quickly determine the impact of various parameters on performance of vertical single U-tube borehole heat exchanger. Furthermore, the obtained result can be utilized as a reference for the design and optimization of heating and cooling system integrated with ground coupled heat pump system.

Small and medium industries (SMEs) savings analysis can help to reduce energy consumptions and greenhouse gas emissions (GHG) and support the individual company to make a better decision to improve facility energy performance. The main idea was to get enough data to recreate simple Excel-based tool so that SMEs could conduct quick energy and GHG emission benchmarking and to come up with potential savings by using their utility bills and plant specifications. Having such knowledge will help these industries to promote energy efficiency, sustainability, and competitiveness in their operation. Energy consumption data of eleven companies have been collected and analyzed. The methodology involves energy benchmarking, separation of process and seasonal energy consumptions, heating degree days estimation, normalized annual energy consumption, and normalized process and seasonal energy consumptions. The leading performance indicator was identified energy intensity of oven. It was estimated, the energy intensity of bake ovens varies from 24 m3/ft3 to 30 m3/ft3, while the energy intensities of ovens with finishing process varies from 8 m3/ft3 to 36 m3/ft3. Potential savings can be realized from retrofits such as the addition of a VFD controller (exhaust loss), insulation (shell loss). Depending on the investment and the type of estimated retrofits, the return on investment can be realized in less than a year or up to ten years. It was also noted that by optimizing production scheduling; 8%–69% of energy consumption could be saved by proper shut-down and scheduling the non-production hours.

Due to their significant internal heat gain resulting from computer server banks, data centres require cooling year-round, creating an opportunity to transport the waste heat to heat-deficient neighbouring buildings. This paper evaluates the quantity of multi-unit residential buildings (MURBs) that should be connected to a given data centre in order to maximize the portion of shared energy which provides the MURBs’ heating energy and the data centre's cooling energy simultaneously. The paper then evaluates the financial viability and greenhouse gas (GHG) emissions of three different methods with which energy can be shared from a data centre to surrounding MURBs in a community energy network (CEN). The first method, called the Energy Sharing System involves using a heat pump to produce heating and cooling at the same time for the MURBs and the data centre. The second, called the One-Borefield System, has the same energy sharing aspect as the first, with additional heating and cooling coming from geo-exchange. The third method, called the Two-Borefield System, is an innovative approach to geo-exchange, which uses two separate borefields to achieve free cooling, while also incorporating the energy sharing base. The investigation finds that the optimal MURB area that should be connected to a 4000 kW cooling load data centre is 110,000 m2 for the Toronto (Canada) climate. The financial analysis shows that the Energy Sharing System was the most profitable, with a 11.9% 30-year unlevered after-tax internal rate of return (IRR).

A monitoring system was developed and implemented in the Archetype Sustainable House (ASH) of the Toronto and Region Conservation Authority (TRCA) for testing the performance of a gas-fired absorption heat pump various inlet temperatures at three different flowrates of glycol-water mixture, containing 50% propylene glycol. Results show that at 50% concentration of propylene glycol the output capacity of the GAHP is approximately 12–13 % lower than the specified capacity. Furthermore, at nominal flowrates in heating mode, the gas utilization efficiency (GUE), which is the ratio of heating (or cooling) output to the thermal energy input, stays above ‘1’ for outdoor temperatures down to –5 oC, implying that GAHP is more efficient than conventional heating equipment up to that point. Below –5 oC the GUE drops below ‘1’ and the GAHP acts like a conventional high efficiency boiler which means that GAHP is either better than or just as efficient as conventional heating equipment depending on the outdoor temperatures. However, the magnitude of energy savings achieved greatly depends on how frequently temperatures below –5 oC are encountered in a given heating season.

This preliminary study is part of a bigger cloud-based smart dual fuel switching system (SDFSS) for hybrid heating, ventilation and air conditioning (HVAC) systems. The SDFSS being developed enables flexible and cost-optimized control between the natural gas furnace and air source heat pump (ASHP), allowing simultaneous reduction in energy costs and greenhouse gas (GHG) emissions. To meet the optimal energy consumption requirements and satisfaction of the residents, the employment of smart sensors and software are broadly used. The data regarding the outdoor temperature plays the most crucial role in operating and controlling the SDFSS optimally. This study introduces a novel approach to obtaining the outdoor temperature that could potentially replace smart sensors with a data-driven model utilizing weather station data at time resolutions of 2 minutes and 1 hour. In this work, a computer program was implemented under Matlab R2018a software. This study found that the artificial neural network (ANN) model was able to predict the outdoor temperature within 0.95 R error in average, demonstrating ANN to be a powerful tool in predicting outdoor temperature. Thus, the model proposed can be confidently implemented as an alternative to temperature sensors in automated systems, in hybrid energy systems or other energy systems requiring accurate ambient temperature measurements.

This paper examines the energy consumption of varying aspect ratio in multi-unit residential buildings in Canadian cities. The aspect ratio of a building is one of the most important determinants of energy efficiency. It defines the building surface area by which heat is transferred between the interior and exterior environment. It also defines the amount of building area that is subject to solar gain. The extent to which this can be beneficial or detrimental depends on the aspect ratio and climate. This paper evaluates the relationship between the geometry of buildings and location to identify a design vernacular for energy-efficient designs across Canada.

A net-zero energy house was outfitted with IoT technology and devices to monitor its energy generation and consumption. The house has a rooftop PV array, an efficient hybrid (or dual-fuel) HVAC system, and efficient appliances to achieve net-zero status. Signals between the thermostat and the HVAC system were intercepted by a custom-built wifi-enabled circuit board to transmit the operating status of the HVAC unit and receive control signals from a remote server for optimal supervisory control. The project was developed as a proof of concept to show that a cloud-based intelligent control system that automatically chooses the best fuel source to use can benefit the homeowner (19% energy cost savings is possible) and contribute to decarbonization (29% reduction). If employed on a wide scale with a smart grid that sends pricing and demand response signals, huge potentials in reducing carbon emissions can be achieved without sacrificing homeowner costs and comfort.

In this paper, gray-box models of a residential HVAC system commonly found in Canadian households are developed. The system comprises of four mjor subsystems called heat recovery ventilator (HRV), air handling unit (AHU), air source heat pump (ASHP) and zone. Models were developed by writing energy balance equations of each subsystem. Measured data from residential HVAC system of Archetype Sustainable House located in Vaughan, Canada was used for parameter estimation and validation of each subystem model. The house is outfitted with temperature, flow rate and power consumption measurement sensors for all subsystems. Two distinct sets of parameeters were found using winter and summer datasets. Parameter estimation was carried out using pattern search with Latin hypercube method and Active-Set algorithm. Developed models were evaluated against measured data using several performance comparison metrics and showed a very high value of goodness of fit in the range of 70% and 88% during both winter and summer seasons.

Wind energy is one of the most promising renewable energy resources for power generation, and rapid growth has been seen in its acceptance since 2000. The most acceptable classification for wind turbines is by its axis of orientation: Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines (VAWT). HAWTs are used in many countries for medium-to-large scale power projects, and most commercial installations around the globe are solely based on these turbines. On the other hand, HAWTs are not recognized as a viable option to harness the energy of the wind in urban areas, where the wind is less intense, much more chaotic and turbulent. VAWTs are suggested as a better choice for cities and isolated semi-urban areas. Several attributes have been suggested for the large-scale deployment of VAWTs, e.g., good performance under the weak and unstable wind, no noise and safety concerns, and aesthetically sound for integration in urban areas. Significant research has been published on wind turbine technology and resources assessment methodologies, and this review paper is a modest attempt to highlight some of the major developments of VAWTs, with a focus on the integration with urban infrastructure. Several recommendations have been drawn based on the state-of-the-art information on the subject for future studies and acceptance of wind turbines in the urban areas. It was concluded that further research is critical in making VAWTs a viable, dependable, and affordable power generation technology for many low and decentralized power applications.

In this paper black-box models of residential HVAC systems commonly found in many Canadian households are developed. The models are useful for performance evaluation, operating point optimization, energy and cost optimization, and new control system design. The HVAC system under investigation is installed at House A of Toronto and Region Conservation Authority's (TRCA) Archetype Sustainable House (ASH) in Vaughan, Ontario, Canada. The system is comprised of four major subsystems, i.e., heat recovery ventilator (HRV), air handling unit (AHU), air source heat pump (ASHP) and the building envelope (zone). Data measured during the winter and summer of 2015 was used to develop black-box models of the system during both seasons for each subsystem. The developed models include artificial neural network (ANN) model, transfer function model (TF), process model, state-space model and auto-regressive exogenous (ARX) model. The performance of these models was compared both visually and analytically. Though visual comparison indicated that all models performed well, the analytical comparison revealed the true differences between them. It was found that state-space models outperformed all other models, the ANN and transfer function models were second best, which were followed by process models and ARX models. Grey-box models developed in a previous paper were also added for comparison, but all black-box models outperformed the grey-box models.

This study investigated the benefits of implementing wall-mounted Building Integrated Photovoltaic Thermal Systems (BIPV/Ts) combined with an Air Source Heat Pump (ASHP) on a mid-rise office building located in 5 major Canadian cities. The study objective involved determining the decrease in ASHP compressor power consumption due to the installed system; the duration of its operation when it was non-reliant on the grid, and the magnitude of building CO2 emissions reduction in the cities. The research approach entailed an evaluation of the hourly solar radiation potential on a vertical surface; undertaking an energy balance across the BIPV/T panels; computing the improvement of the Coefficient of Performance of the ASHP compressor and calculating the total hourly solar power generation on the south, east, and west orientated BIPV/T arrays. The results showed that at several locations and climatic conditions, a 12x5 BIPV/T array on the south facade in combination with 12x4 BIPV/T arrays on the east and west facades could completely meet the power demand of an ASHP compressor during certain spring months, and even reduce it up to 50% during the colder winter months. Furthermore, this study's novelty is that it also demonstrated that the comparative feasibility of the system in the different cities depended on factors that went beyond the focus on electricity use reduction. This study also highlighted the prevailing local and regional conditions, such as the fuel sources responsible for electricity production, building function and the type of occupancy and even provincial regulations such as prescribed glazing ratios, which would influence decision making in regards the potential installation of the proposed system. It is important that in the efforts towards reducing CO2 emissions, designers and PV technology experts must not always go for the “one-fits all” approach and that design solutions must be targeted to specific contexts.

Borehole heat exchanger (BHE) is a very suitable and cost-effective technology for heat storage and extraction of heat from the ground. In this paper, comprehensive analysis of major influencing parameters on thermal performance of single U-tube BHE (sBHE) and double U-tube BHE (dBHE) was performed by using validated numerical heat transfer model. Combined effect of increasing borehole size and soil or grout thermal conductivity (for different cases of shank spacing) on performance of sBHE and dBHE was studied. Detailed comparative analysis of thermal performance was made among sBHE and dBHE with small and large borehole sizes. The impact of borehole depth and diameter, fluid inlet temperature, mass flow rate, U-tube pipe material type and diameter on total heat transfer per unit borehole depth, borehole thermal resistance and thermal effectiveness was also investigated. The simulation result revealed that when the shank spacing is kept at high or low value in sBHE and dBHE (both with small and large borehole size), dBHE with larger borehole size has the highest thermal performance while sBHE with smaller borehole size has the lowest performance; and the highest and the lowest thermal resistance is obtained for sBHE with smaller borehole size and dBHE with larger borehole size, respectively. Grout with high thermal conductivity is preferred in terms of improving thermal effectiveness and reducing thermal resistance of the BHE when the soil thermal conductivity is sufficiently high; while low grout thermal conductivity is preferred with large borehole size and high shank spacing. For high soil thermal conductivity (4W/m.K), the heat transfer rate per unit borehole depth increases with grout thermal conductivity to a maximum value; and then further increasing of the grout conductivity results in smooth declining of the heat transfer in the BHE. Thus, ground and grout thermal conductivity have an optimal range to achieve a lower value of the BHE thermal resistance, and consequently for better BHE sizing. With increasing fluid inlet temperature (15oC to 42oC), the total heat transfer is improved by 51.5 W/m and 36.2 W/m for dBHE and sBHE respectively; and more heat is injected into the borehole when dBHE is used than sBHE, particularly at higher inlet temperature showing that dBHE is preferable than sBHE for system that works with higher fluid inlet temperature. The result obtained can be used as a quick reference for the design, operation optimization and performance study of ground coupled heat pump system where BHE is used as aborehole thermal energy storage.

Through tests conducted at the Toronto and Region Conservation Authority’s (TRCA) Archetype Sustainable Houses, a hybrid residential space heating system with a supervisory controller was monitored and studied to evaluate its performance and effectiveness for the heating season. A high efficiency natural gas furnace (NGF) and an electric air source heat pump (ASHP) were coupled together to meet the space heating demand of the house. This integrated system is called the cloud based Smart Dual Fuel Switching System (SDFSS) that considers time-of-use (TOU) pricing, fuel cost, short-term weather forecast, and equipment efficiencies and capacities. This multi-variable decision-making process defines an optimal schedule for the hybrid system to run more cost effectively. This paper analyses two separate SDFSSs. According to these analyses, the SDFSS systems showed lower operating cost with respect to the furnace or the ASHP system alone with various carbon tax (CT) levels from $0 to $250/tonne of CT with an increment of $10/tonne of CT that were simulated, along with a significant GHG emission reduction relative to the conventional heating systems. Furthermore, with these technologies, Canada’s residential sector could potentially meet Canada’s Paris Agreement goals. The SDFSS technology is a is flexible, user friendly, ubiquitous technology for the smooth transition from today’s natural gas dominated space heating system to the future’s low carbon infrastructure powered by a heat pump and renewable energy.

In Canada, more than 80% of energy in the residential sector is used for space heating and domestic hot water (DHW) production. This study aimed to model and compare the performance of four different systems, using solar energy as a renewable energy source for DHW production. A novel microchannel (MC) solar thermal collector and a microchannel-based hybrid photovoltaic/thermal collector (PVT) were fabricated (utilizing a microchannel heat exchanger in both cases), mathematical models were created, and performance was simulated in TRNSYS software. A water-to-water heat pump (HP) was integrated with these two collector-based solar systems, namely MCPVT-HP and MCST-HP, to improve the total solar fraction. System performance was then compared with that of a conventional solar-thermal-collector-based system and that of a PV-resistance (PV-R) system, using a monocrystalline PV collector. The heat pump was added to the systems to improve the systems’ efficiency and provide the required DHW temperatures when solar irradiance was insufficient. Comparisons were performed based on the temperature of the preheated water storage tank, the PV panel efficiency, overall system efficiency, and the achieved solar fraction. The microchannel PVT-heat pump (MCPVT-HP) system has the highest annual solar fraction among all the compared systems, at 76.7%. It was observed that this system had 10% to 35% higher solar fraction than the conventional single-tank solar-thermal-collector-based system during the wintertime in a cold climate. The performance of the two proposed MC-based systems is less sensitive than the two conventional systems to collector tilt angle in the range of 45 degrees to 90 degrees. If roof space is limited, the MCPVT-HP system is the best choice, as the MCPVT collector can perform effectively when mounted vertically on the facades of high-rise residential and commercial buildings. A comparison among five Canadian cities was also performed, and we found that direct beam radiation has a great effect on overall system solar faction.

In the ground coupled heat pump system that delivers space heating and cooling to the buildings, often questions are raised as to which borehole heat exchanger configuration (single or double U-tube) provides higher thermal performance. To answer this question, in this paper, detailed comparative transient heat transfer analysis between single and double U-tube borehole heat exchanger (BHE) with two independent circuits (that can operate with the same or different mass flowrate and inlet fluid temperature) is conducted. Validated numerical heat transfer model was applied to perform the dynamic simulation and analysis. The two borehole heat exchangers are compared from the perspectives of their thermal performance in the heating and cooling mode of operation. Detailed sensitivity analysis of the BHE has also been performed by investigating the impact of the important borehole parameters, thermal properties and working fluids on the thermal performance of the double U-tube BHE. The simulation result revealed that the heat injected and extracted by the double U-tube BHE at steady state is 21.8 (77%) and 10.2 W/m (71.8%) more than that of the single U-tube BHE respectively. The simulation results also indicate that the thermal effectiveness of the single and double U-tube BHE at steady state are 0.24 and 0.31 respectively. The single U-tube BHE showed higher borehole thermal resistance than that of the double U-tube BHE with values of 0.47 and 0.31 m.K/W, respectively. The results of the study also revealed that among the studied working fluids, CaCl2 (25%) solution showed better thermal performance than other anti-freeze solutions with thermal effectiveness of 35.6%. The simulation result of this work is crucial as an input for the optimization studies made to obtain a single set of optimal borehole paramaters and thermal properties that results in the best performance of BHE coupled to ground source heat pump system designed to provide space heating and cooling of buildings.

Thermal performances of two phase change materials (PCM) in the Toronto's Net-Zero Energy House are compared and contrasted with commonly available forms of thermal mass. TRNSYS simulations show that the use of thermal mass was found to contribute to energy savings of 10–15% when different types of thermal mass were mixed into the building envelope. The results exhibit that the performance of a novel solid-solid phase PCMs, recently developed by researchers at Dalhousie University and known as DalHSM-1, could be comparable to a commercially available PCM from BASF (Micronal) in the heating mode. The cooling mode performance revealed that DalHSM-1 provided lower energy savings when compared to Micronal, due to a lower phase transition temperature and latent heat. The impact of thermal mass on the occupant comfort was also investigated by considering the total number of hours where the temperature exceeded the heating set point of 21 °C. The results showed that the total number of hours where the temperature exceeded 21 °C could be reduced significantly with different types of thermal mass, thus contributing considerably to the comfort of the occupants.

In this paper, a comprehensive review of the artificial neural network (ANN) based model predictive control (MPC) system design is carried out followed by a case study in which ANN models of a residential house located in Ontario, Canada are developed and calibrated with the data measured from site. A new algorithm called best network after multiple iterations (BNMI) is introduced to help in determining the appropriate ANN architecture. The prediction performance of the developed models using BNMI algorithm was significantly better (between 6% and 59% better goodness of fit for various models) when compared to a previous study carried out by the authors which used the default single iteration ANN training algorithm of MATLAB®. The ANN models were further used to design the supervisory MPC for the residential HVAC system. The MPC generated the dynamic temperature set-point profiles of the zone air and buffer tank water which resulted in the operating cost reduction of the equipment without violating the thermal comfort constraints. When compared to the fixed set-point (FSP), MPC was able to save operating cost between 6% and 73% depending on the season.

Borehole thermal energy storage (BTES) is found to be a favorable method for storing a large amount of thermal energy, and suitable for seasonal solar thermal storage, especially for large communities. Drake Landing Solar Community (DLSC), built in 2006, is the first such solar community in Canada. DLSC has achieved a 97% solar fraction after five years of operation. Although the DLSC project has been a success technically, the cost of the system is not attractive. In this study, an alternative design approach for a similar community is presented. The primary goal is to develop a system that not only achieves similar or better performance but also costs less. TRNSYS 17, along with a novel custom BTES component, is used for the system design and simulation. With the alternative design, the annual community thermal load of 2350 GJ is mostly met by solar thermal collectors via BTES and after five years of operation a 96% solar fraction is predicted. The simulation results are compared with published results for DLSC. It is estimated that the proposed system offers a 19% saving in initial cost in addition to reductions of BTES area of 38% and solar panel area of 25%.

The driving and charging patterns of battery electric vehicles can have a significant impact on the load profile of the distribution grid. Renewable resources and controlled charging can mitigate this effect by reducing the energy imported from the grid. The smart real-time electric vehicle charging scheduling proposed in this paper reduced grid peak demand through dynamic programming that uses future renewable supply and electric vehicle demand predictions to optimize the balance of energy in the electric grid. The large-scale driving, charging and parking availability patterns used in the simulations were synthesized from an actual experiment made up of a commercial fleet of battery electric vehicles. Numerical simulations showed that for commercial-use vehicles, solar photovoltaic and hybrid photovoltaic +wind technologies can reduce annual grid demand by 24%. Smart scheduling of electric vehicles and the integration of renewable energy resulted in lower peaks but no significant shift in the peak hour demand was observed.

Photovoltaic–thermal (PV/T) collectors provide renewable energy, and they are instrumental to achieve grid independency. A subset of these collectors is collectors that are integrated into building envelope. The so-called “building-integrated” PV/T collectors have seen a dramatic rise in popularity recently. This recent popularity has necessitated systematic design optimization. To benefit design optimization, a review of computer models of these collectors was performed. This review was performed by objectively assessing international findings on roof-integrated and curtain-wall integrated PV/T collectors. The scope of this review was thermal collection efficiency. The significance of this review was to identify the weakest link in computer models that should one day lead to more accurate computer models. This weak link is the internal heat transfer rate. To overcome this weakness, a model calibration method was proposed that is based on case-by-case parameter identification. In addition, a detailed dimensional analysis was performed that allowed a new Π group to be introduced to Nusselt (Nu) number correlations of developing, turbulent parallel-plate flow. This Π group is the Stanton number as applied to the inter-channel radiative heat transfer coefficient (Str). Commonly implemented Nu number correlations do not account for this heat transfer rate. They only account for collector geometry, collector air flow inertia and collector air viscosity.

Building energy simulators such as TRNSYS, EnergyPlus, and Esp-r offer an excellent opportunity for detailed design of house thermal model and its Heating, Ventilating, and Air Conditioning (HVAC) system and provide very accurate simulation results useful for performance analysis and optimization process. In contrast, these energy simulators do not include sub-models of advanced devices/strategies for control of HVAC system operation and suffer from poor control mechanism. In addition to lack of an advance controller, they inherently offer no mechanism for estimating the future state of their process models based on forecast weather dataset. Hence, no predictive controller can be designed and implemented within these simulators. This paper discusses the development of a Matlab-TRNSYS co-simulator in order to control/manage a TRNSYS program, which was previously developed and calibrated based on the characteristics of a real case study house, with an advanced predictive controller. This co-simulator investigates the effectiveness of different predictive strategy planning models, including Load Shifting (LSH), Smart Dual Fuel Switching System (SDFSS), and LSHSDFSS, as the integration of fuel switching and load shifting strategy planning models on 24 h ahead energy cost saving of the case study house HVAC system. Simulation results of different consecutive sample days indicate that SDFSS could bring significant energy cost saving. However, LSH and LSHSDFSS effectiveness is sensitive to the outdoor temperature.

This research presents a method to determine the maximum potential for the capturing of solar radiation on the rooftop of buildings in an urban environment. This involves the modeling of solar energy potential and comparison to historical building energy demand profiles through the use of 3-D solar simulation software tools and geographic information systems (GIS). The objective is to accurately identify the amount of surface area that is suitable for solar photovoltaic (PV) installations and to estimate the hourly PV electricity generation potential of existing building rooftops in an urban environment. This study demonstrates a viable approach for modeling urban solar energy and offers valuable information for electricity distributors, policy makers, and urban energy planners to facilitate the substantial design of a green built environment. The developed methodology is comprised of three main sections: (1) determination of suitable rooftop area, (2) determination of the amount of incident solar...

This paper proposes numerical unsteady heat transfer model that predicts the transient heat transfer in the double U-tube borehole heat exchanger (BHE) where the U-tubes can operate with either different or equal mass flow rate and inlet fluid temperature. The implicit numerical method applied on heat transfer equations, obtained from energy balance on fluid, grout and ground nodes, was utilized to get the solution. The profile of the borehole loading as well as the net heat exchange on each leg of the U-tube along the borehole depth were obtained for simultaneous charging, discharging, and charging-discharging conditions. Axial variation of the mean fluid temperature, grout and borehole wall average temperature for charging and discharging cases were investigated. The model is extended to consider the axial and radial variation of ground temperature outside the borehole. Dynamic simulation was performed for different operating conditions to investigate various temperature response, borehole thermal resistance as well as thermal performance of the BHE. The proposed model was verified with the previously published experimental results. The performed modeling, simulation and analysis are important for the vertical BHE system optimization, efficiency testing as well as for the quick investigation of the impact of the borehole parameters and thermal properties on the overall performance of the BHE. The model is crucial in the design, optimization and performance study of ground source heat pump and borehole thermal energy storage systems.

This paper presents a thermodynamic analysis of a poly-generation system powered by solar thermal energy using parabolic trough collectors. The proposed system consists of an organic Rankine cycle, a multiple effect distillation and an absorption cooling unit. The performance analysis of the solar system is conducted for different configurations: power generation only, cogeneration power and cooling, cogeneration power and desalination, and poly-generation. The effects of turbine inlet temperature and pump inlet temperature on the energetic and exergetic system performance as well as the net power output and total exergy loss of the system are examined. In addition, exergetic parameters, including system total exergy loss, fuel depletion ratio and improvement potential were analyzed. The study reveals that increasing the turbine inlet temperature increases the performance while it reduces the total exergy destruction rate of the system. The result of the study also shows that the two main sources of exergy destruction are the solar thermal collector and desalination unit; with 49.3% of the input exergy (76% of the total exergy loss) destructed in the collector while 9.6% of the inlet exergy (14.9% of the total exergy loss) is destroyed in the desalination system. The overall improvement potential of the system was found to be 64.8%.

Machine learning algorithms using Artificial Neural Network (ANN) were developed to predict the performance of heat pump systems in retrofit residential housing. The study attempts to address the research gap in the application of machine learning algorithms to real-life field measurements as a case study. Rowhouse units with electric resistance baseboard heating were retrofitted with Ductless Air Source Heat Pumps (DASHPs). Sensors were installed to collect the energy consumption data during the baseboard and DASHP monitoring periods. Linear and quadratic regression methods following the International Performance Measurement and Verification Protocol (IPMVP) were applied to predict energy consumption based on outdoor temperature and heating degree days. These predictions were compared against results from ANN models based on Levenberg-Marquardt algorithms using the hour of the day, day of the week, outdoor temperature, wind speed and direction, relative humidity, condition and indoor temperature as inputs. Preliminary results indicate that predictions from ANN models produced higher correlation of determination than those from IPMVP regression analysis.

Energy benchmarking (EB) has become a popular method for the estimation of energy consumption and overall performance improvement in buildings and industrial facilities. The industrial plant ventilation system is one of the most overlooked and underestimated components in terms of total industrial sector energy consumption. A proper assessment and management of energy use in industrial ventilation systems can lead to a considerable reduction in energy consumption, cost, and greenhouse gas (GHG) emissions. The main objective of this study is to present comprehensive EB along with analysis of energy consumption and saving opportunities. The energy analysis was conducted for fourteen Small to Medium-Sized Enterprises (SMEs) in the Greater Toronto Area (GTA). The building’s ventilation load analysis was developed, and a comparison with similar types of companies was performed to determine the natural gas (NG) consumption, GHG, and energy cost savings. It was determined that the inefficient performing facilities could reduce an average of 9% of their total NG consumption from mechanical ventilation, 25% from transmission heat loss, and 10% from infiltration loss as compared to the top-performing facility.

This paper is intended to develop a detailed thermal and electrical model of a transparent backing Building Integrated Photovoltaic/Thermal (TBIPV/T) collector integrated to the roof. This model was used to assess the energy performance of a typical transparent PVT air collector. The energy balance equations were derived for glazing glass, the PV cells, glass back surface of the PV module, air flowing in the duct of TBIPV/T collector and back insulation surface. The energy equations were solved using FORTRAN. A new TRNSYS type was created for the transparent backing PVT system. This type is intended to function with multi-zone building model in TRNSYS, that means thermal interaction between the PV/T collector and the building was taken into account. The effect of different PVT system parameters such as PV cell packing factor, panel cover optical properties on thermal energy production and electricity generation were examined and discussed.

In this paper the performance of a ground source heat pump (GSHP) system with horizontal coupled ground loop pipes was monitored, analysed, extrapolated and numerically simulated. The state-of-art facility of the Kortright Centre was used to experimentally monitor the performance of GSHP. The main objective was to develop cooling/heating performance curves based on the building loads and the source temperatures. In addition, it was aimed to evaluate the efficiency of the heat pump at different load/source temperatures and measure the cycling characteristics of the compressor. Furthermore, the heat pump was modelled using the performance curves obtained from the experimental investigation. TRNSYS was used to model the house as well as the heat pump. The model was validated using the daily thermal output and it was determined that the COP ranged from 3.05 (at an ELT of 44.4 °C and an EST of 2.7 °C) to 3.44 (at an ELT of 41.5 °C and an EST of 5.48 °C). The system was also investigated for potential improvements in the control strategies. The aim was to identify issues with the current controls of as installed system and determine methods for possible improvement in the overall efficiency.

This paper presents an investigation on the performances of drain water heat recovery (DWHR) system and two solar domestic water heaters (SDWH). The DWHR units and water heater systems were recently installed side-by-side at the Archetype Sustainable Twin Houses at Kortright Center, Vaughan, Ontario. The first SDWH system in House A consists of a flat plate solar thermal collector in conjunction with a gas boiler and a DWHR unit. The second SDHW system in House B consists of an evacuated tube solar collector, an electric tank, and a DWHR unit. The extrapolated results based on the experimental study showed that the DWHR unit is capable of an annual heat recovery of 789 kWh and an overall effectiveness of about 50%. The flat plate and evacuated tubes collectors based SDWH systems produce an annual thermal energy output of 2038 kWh and 1383 kWh, respectively.

In this study, the thermal impact of defrost cycle of both residential heat and energy recovery ventilators (HRV and ERV) was investigated using TRNSYS. The thermal efficiency patterns of the units were obtained from winter experiments, and then implemented into the existing HRV and ERV models for simulations in the context of airtight environment. Throughout the heating season, the minimum humidity of the airtight house was increased due to the reintroduction of humid indoor air/melted frost. For the HRV, simulation results indicated that its yearly demand of defrost cycle was 3.5 times higher the ERV. In other words, the HRV used in cold days could significantly deteriorate indoor air quality, which contradicted the main purpose of mechanical ventilation.

An investigation is reported on the performance of a two-stage variable capacity air source heat pump (ASHP) system, recently installed at the Archetype Sustainable House (ASH) in Woodbridge, Ontario, Canada. The controlled testing on the system was carried out in both summer and winter seasons for 4 to 6 weeks. TRNSYS simulation was performed and validated to model the performance of ASHP. The experimental data were extrapolated to predict the annual performance of ASHP. It was noticed for the cooling mode, the coefficient of performance (COP) varied between 4.7 to 5.7 as the outdoor air temperature changed from 33 °C to 16 °C, respectively. While in the heating mode, the COP varied between 1.79 and 5.0 as the temperature of outdoor air changed from −19 °C to 9 °C, respectively. The performance result has indicated that the use of variable speed ASHP provides an improvement in the efficiency as compared to other available options. These enhancements are due to the reduction in the operating cyclic time and relatively lower operating speeds of the device.

This paper presents a performance comparison of a variable capacity Air Source Heat Pump (ASHP) and a horizontal ground loop Ground Source Heat Pump (GSHP). Both these systems were installed side-by-side at the Archetype Sustainable Twin Houses at Kortright Center, Woodbridge, Ontario, Canada. The heat pumps were tested in both heating and cooling modes for extreme weather conditions of Ontario. For cooling mode, the coefficient of performance (COP) of ASHP ranged from 4.7 to 5.7 at an outdoor temperature of 33 °C and 16 °C respectively, while the COP of GSHP ranged from 4.9 (at an ELT of 8.5 °C and EST of 19.2 °C) to 5.6 (at an ELT of 12.4 °C and EST of 17.8 °C). For heating mode, the COP of ASHP ranged from 1.79 to 5.0 at an outdoor temperature of −19 °C and 9 °C respectively, while the COP of GSHP ranged from 3.05 (at an ELT of 44.4 °C and an EST of 2.7 °C) to 3.44 (at an ELT of 41.5 °C and an EST of 5.48 °C). Data extrapolation and TRNSYS simulation were also performed to predict annual performances of each system for major Canadian cities.

This paper presents a review of the available literature on solar systems (solar thermal collectors and Photovoltaic–Thermal (PV/T) collectors) and their integration with heat pumps. Most of the research covered in this review show that the dominant source of solar assisted heat pumps (SAHPs) is liquid with a thermal storage; direct expansion or indirect expansion. SAHPs are mostly used for heating purposes. Few studies investigated the possibilities of combining a solar system with an air source heat pump (ASHP). The integration of a PV/T system with a heat pump, which provides both thermal energy and electrical power, existing in most researches is PV-evaporator type, which is the evaporator of the heat pump. It is required to control the mass flow rate of the refrigerant to prevent remaining liquid refrigerant at the outlet of the PV-evaporator due to the fluctuation of solar radiation; consequently, the system works inefficiently. It is possible to overcome this issue by separating the PV/T unit from the heat pump evaporator. There is a lack of investigations of connecting an air-based solar system (especially PV/T system) with an ASHP, including air-based thermal energy storage.

The two identical energy efficient houses, “Energy Star” House (EH) and “Green” House (GH), located in Ontario were chosen to investigate the effectiveness of energy efficiency measures in dwellings. EH was built based on the Energy Star standard while GH had a number of additional energy savings and sustainable green features. Both houses’ energy consumption were simulated and their utility bills weather normalized by using HOT2000 building energy simulation software and Princeton Scorekeeping Method (PRISM). Although GH was expected to consume less energy than EH, considering GH's more energy efficient mechanical system and building envelope, this study showed that EH consumed less energy than GH (annual energy consumption of EH is 44% less than GH). Further investigation on occupants’ behavior and usage of the both houses using a survey showed clearly that having energy efficient systems do not necessarily lead to lower energy consumption.

The potential of conventional heat/energy recovery ventilators have been widely studied, whereas the impacts of defrost cycles are usually neglected. An energy recovery ventilator (ERV) was studied in the Archetype Sustainable House-B (ASH-B) located in Toronto, Ontario. The study provides an experimental evaluation of the efficiency of the ERV unit during normal and defrost operations, as well as its frost resistance to a range of winter temperatures. The parameters that were considered included fan power draw, inlet and outlet air temperatures, humidity, and airflows. Operating the ERV without the defroster revealed a frost resistance of up to −16 °C. In addition, the data analysis of defrost cycle revealed two stages of change of fresh air temperature and humidity, which can be used to predict the thermal performance of the ERV unit under different operating conditions.

This survey paper is an excerpt of a more comprehensive study on Smart Grid (SG) and the role of Advanced Metering Infrastructure (AMI) in SG. The survey was carried out as part of a feasibility study for creation of a Net-Zero community in a city in Ontario, Canada. SG is not a single technology; rather it is a combination of different areas of engineering, communication and management. This paper introduces AMI technology and its current status, as the foundation of SG, which is responsible for collecting all the data and information from loads and consumers. AMI is also responsible for implementing control signals and commands to perform necessary control actions as well as Demand Side Management (DSM). In this paper we introduce SG and its features, establish the relation between SG and AMI, explain the three main subsystems of AMI and discuss related security issues.

A TRNSYS model was developed to integrate photovoltaic/thermal collector (PV/T) in a roof and coupled with Air Source Heat Pump (ASHP) in an Archetype Sustainable House (ASH). The heat pump uses the warm air generated in the Building Integrated Photovoltaic-Thermal Collector (BIPV/T) as the source for heat production. The coupling of BIPV/T and ASHP enables a highly efficient heating system in winter conditions. The developed TRNSYS model was simulated for different regions to predict the seasonal performance of the heat pump. The results from the simulation were used to estimate the saving in energy and cost as well as to predict the electricity related greenhouse gas (GHG) emission reduction potential from the PV panels. The results showed that annual GHG emission due to electricity demand by the ASHP was reduced by 225 kg CO2 for ASHP + PV/T. The annual electricity cost credit from PV production based on Time-of-Use (TOU) and the reduction in electricity cost of the heat pump when connected with PV/T systems was calculated and compared with the cost of working the heat pump alone. The results showed that there was a saving of $500 in annual electricity bills and GHG emission credit of 1734.7 kg CO2 from renewable electricity generation.

This paper is focused on the steady-state performance of a hybrid solid oxide fuel cell (SOFC)-gas turbine (GT) cycle. First, the model of the hybrid SOFC-GT cycle is developed and then the model is used to perform a series of sensitivity analyses to investigate the impact of various design and operating parameters on the performance of the cycle without anode recirculation when the system is fuelled with methane. The following system operating and design parameters are investigated: SOFC operating temperature, fuel utilization factor, current density; system operating pressure; turbine inlet temperature (TIT); and isentropic efficiency of the GT. The system performance is monitored by recording and evaluating the specific work of the SOFC, GT, and system as a whole; SOFC-to-GT work ratio; and cycle efficiency (based on the LHV). The results of the modeling illustrated that the cycle efficiency can be improved by increasing system operating pressure, SOFC operating temperature, and GT isentropic efficiency and decreasing SOFC current density and TIT. Also, it is shown that increasing system operating pressure, fuel utilization factor, and TIT can positively affect cycle net specific work, while increasing SOFC operating temperature and SOFC current density has negative impact on the cycle net specific work. The influence of the fuel utilization factor on the cycle efficiency depends on the GT isentropic efficiency.

Currently, heat recovery ventilator (HRV) and energy recovery ventilator (ERV) are commonly studied. Nevertheless, there is limited information regarding the dual-core approach energy recovery. This paper investigates the feasibility of an integrated HRV and ERV system, namely HERV, with a built-in economizer used in the residential sector to reduce dependency on furnace and air conditioning systems. In order to achieve this goal, an excel-based analysis tool was developed, providing a quick estimate of system performance and comparison with the HRV and ERV that are currently being used in research houses. The potential of integrated heat and energy recovery ventilator was evaluated based on its calculated operating cost ratio (OCR) and its payback period. Results collected for Vancouver and Toronto, corresponding to temperate and continental climate, indicated that the OCRs of the HERV were four times smaller than the ERV's, meaning that the proposed system was cost-efficient. It was also evidenced that the high demand on the economizer resulted in higher energy saving and shorter payback period of the system. In conclusion, the integrated HERV system with a built-in economizer could be a feasible option for both temperate and continental climates.

In this paper, the model of hybrid solid oxide fuel cell (SOFC) and gas turbine (GT) cycle is applied to investigate the effects of the inlet fuel type and composition on the performance of the hybrid SOFC–GT cycle. The sensitivity analyses of the impacts of the concentration of the different components, namely, methane, hydrogen, carbon dioxide, carbon monoxide, and nitrogen, in the inlet fuel on the performance of the hybrid SOFC–GT cycle are performed. The simulation results are presented with respect to a reference case, when the system is fueled by pure methane. Then, the performance of the hybrid SOFC–GT system when methane is partially replaced by each component within a corresponding range of concentration with an increment of 5% at each step is investigated. The results point out that the output powers of the SOFC, GT, and cycle as a whole decrease sharply when methane is replaced with other species in majority of the cases.