Proceedings, 2019, SEEBI 2019

Wastewater is an abundant and an underutilized thermal energy source that experiences steady temperatures and predictable flow rates year-round. These characteristics make it an excellent candidate to serve as the heat source and sink for heat pump based HVAC (Heating, Ventilation, and Air Conditioning) systems capable of providing both heating and cooling. The potential for wastewater heat recovery is evaluated for a large hospital in the greater Toronto area, in Canada. A model was developed to calculate the operational savings and benefits of the proposed system, and the results from that analysis were used to carry out an economic analysis. Full article

This paper presents the results of analyzing the potential benefits of a natural gas-fired absorption heat pump (GAHP) for a library building in Ontario in terms of energy savings, fuel cost savings, and reduction in greenhouse gas emissions. Simulation model for the library building was created in eQUEST and calibrated using the energy consumption data from the 2012–2014. The results for energy savings were analyzed to include the effect of implementation of carbon pricing. It was concluded that because of implementation of carbon pricing, the replacement of conventional heating equipment with more efficient gas-fired heat pump would increase the monetary value of the savings achieved from reduced natural gas consumption, due to increased price of natural gas. Furthermore, due to the longer heating season in Canada and the relatively higher price of electricity compared to natural gas the gas-fired heat pump can potentially achieve positive energy cost savings when operated in both heating and cooling mode even after implementation of carbon pricing. Full article

In Canada both residential and commercial buildings often require intensive ventilation and air-conditioning to maintain occupant’s thermal comfort and indoor air quality during the operational hours in cooling season. One way to reduce the cooling load consumption is utilizing mixed-mode cooling approach for space conditioning through natural ventilation. This paper presents the potential of control strategies for motorized window opening schedules to reduce the cooling load for a library building that was designed to be net-zero in terms of annual energy consumption (Canada’s first institutional net-zero energy building in Varennes (near Montreal), Québec, Canada). Even though the building is located in cold climate zone, the performance study shows that the building is cooling dominated i.e., it has more cooling load than heating load. To achieve net-zero energy building status, the potential of mixed-mode cooling approach (natural ventilation combined with mechanical ventilation) during the cooling season needs to be investigated. Preliminary simulation results show that the mixed-mode cooling could achieve 10 to 20% energy savings based on hybrid ventilation (HV) with fixed schedules, whereas 65% savings based on HV with variable schedules. This paper also shows 47% reduction of cooling load could be achieved by applying shading control strategies over without shading control strategies. Full article

Air-to-air energy recovery ventilators (ERVs) are able to reduce the required energy to condition ventilation air in buildings. Among different types of ERVs, fixed-bed regenerators (FBRs) have a higher ratio of heat transfer area to volume. However, there is limited research on FBRs for HVAC applications. This paper presents preliminary experimental and numerical research of FBRs at the University of Saskatchewan. The numerical and experimental results for effectiveness of FBR agree within experimental uncertainty bounds and the results agree with available empirical correlations in the literature. Full article

Recently, major improvement on compressed air energy storage technology has been made by using the heat of compression for heating energy or using it to preheat the compressed air in the expansion phase and by demonstrating its ability to produce cooling energy. Thus, the trigenerative compressed air energy storage has been introduced. In this paper, we introduce a configuration of trigenerative compressed air energy storage system giving the preference to the electric energy production. The study then focuses on undertaking an optimization study via a parametric analysis considering the mutual effects of parameters. This analysis is applied to a micro-scale application including the existing technological aspects. The parametric study results applied on the hot temperature of the thermal energy storage indicate the possibility to find an optimal solution as a trade-off between system performances and other parameters reflecting its cost. On the contrary, the selection of the maximal storage pressure cannot be achieved by finding a compromise between energy density and system efficiency. A complete study of other design parameters will be addressed in a future publication. Full article

An important part of a building energy consumption is related to the domestic hot water consumption of its occupants. Predictive controllers are often considered as having the potential to reduce the energy consumption of hot water systems. In this work, a recurrent neural network is trained from the measured domestic hot water consumption of a 40 unit residential building in Quebec City, Canada, to predict the future consumption. It is found that the water consumption profile of the building changes from day to day throughout the year and has an important noise component. A predicting model is developed in this work and is obtained by pairing a recurrent neural network to predict the filtered domestic hot water demand with a random forest to predict the noise signal. The evaluated performances indices for the prediction of the next demand are satisfying (i.e., RMSE of 142.02 L/h and R² of 0.71). In addition, it is found that the predictions made over the following hour using the same predicting model are accurate and could likely be used in a predictive control context. Full article

Model-based Predictive Control (MPC) is a promising advanced control strategy for the improvement of building operation. MPC uses a model of the building along with weather forecasts to optimize control strategies, such as indoor air temperature set-points, thermal storage charging and discharging cycles, etc. An obstacle to the adoption of MPC is the modelling step: developing a dedicated control-oriented model is a time-consuming process, requiring technical expertise and a large amount of information about the building and its operation. To overcome these issues, this paper proposes a new approach for the development of MPC strategies based on Artificial Intelligence (AI) techniques, aiming to map correlations among commonly available operation variables and to develop models suitable for predictive control. The proposed approach was applied in an institutional building in Varennes, QC, with the aim of reducing the natural gas consumption during the heating season. Early results show a remarkable effectiveness of the proposed approach, with a reduction of natural gas and building heating consumption of 23.9% and 6.3%, respectively. Full article

Exhaust fans in residential buildings generate energy consumption first by the electricity that they require when operating, but also by extracting heat outside of the building. Nonetheless, these appliances are essential to ensure good indoor air quality. It is thus important to study how occupants in residential buildings use exhaust fans and to assess their impact on the energy performance of buildings. In this paper, a preliminary analysis on these two topics is made based on measured data recorded from a multi-residential building located in Quebec City, Canada. Data show that the use of exhaust fans is variable from a household to another. It was estimated that exhaust devices accounted for approximately 14% of the energy demand of the monitored building. Full article