Dominic Groulx

Thermo-economic assessment of end user value in home and community scale renewable energy systems

This study employs thermo-economic analysis to establish a homeowner-centric valuation of renewable energy technologies. The evaluation methodology is illustrated using several classes of renewable energy technology, including, ground-source heat pumps, wind turbines, photovoltaic panels, and solar thermal water heaters. Energy systems employing each of these technologies are examined when servicing the typical domestic energy loads of a single-detached home. Through the analysis, it is learned that single-home photovoltaic systems produce energy at an annual cost approximately four times that of grid electricity, while wind energy systems deliver this energy at approximately twice the cost of grid electricity. Further, single-detached homeowners currently heating with fuel oil and/or grid electricity may expect to save between

Effects of convection and inertia on close contact melting

1000 and

A Method for Reduction in the Start-Up Time of a Bubbling Bed Boiler Combustor

1800 per year when switching to a ground-source heat pump system; whereas those considering the implementation of a solar thermal water heater can expect to spend an add...

THERMAL BEHAVIOR OF PHASE CHANGE MATERIAL DURING CHARGING INSIDE A FINNED CYLINDRICAL LATENT HEAT ENERGY STORAGE SYSTEM: EFFECTS OF THE ARRANGEMENT AND NUMBER OF FINS

Abstract An analytical study was conducted in order to examine the role of convection and inertia on close contact melting of a phase change material (PCM) resting on a sliding heated plate. Results indicate that for high Prandtl substances, inertia has no effect on contact melting regardless of the magnitude of the melt layer Reynolds number Re . Convection however, enhances contact melting and its effect is increasingly perceptible for Re >10 2 . Viscous dissipation may be ignored as long as Re 4 and the Stefan number Ste ⩾0.001. On the other hand, for low Prandtl substances, both convection and inertia influence contact melting. Convection enhances melting while inertia hinders it. The effect of inertia is further accentuated as the Prandtl number becomes smaller. Viscous dissipation remains negligible as long as Re 6 and Ste ⩾0.001.

Economic and energy analysis of domestic ground source heat pump systems in four Canadian cities

A study on the heating of inert bed solids in a bubbling fluidized bed by means of an over-bed start-up oil burner is presented in this paper. Experiments carried out in a 160 mm diameter bed shows that the bed heats up nonlinearly with time. The rate of heating and the peak temperature reached by the bed solids depend on the bed depth, the mean particle size, and the superficial velocity through the bed. It was further noted that premixing a certain amount of biomass with the inert bed solids accelerates the rate of heating, as well as increase the peak temperature attained. The internal heat generation in the biomass is found to start at temperatures as low as 200°C. Thus, premixing some biomass with inert bed materials could reduce the combustion start-up time of a fluidized bed boiler, reducing at the same time the start-up cost by saving on consumption of expensive fuel oil in the burner. Experimental data in the present laboratory-scale unit shows good agreement with those obtained earlier in an industrial fluidized bed tested with waste-coal.

Characterization of an Air-PCM Energy Storage Design for Air Handling Unit Applications

One way of storing thermal energy is through the use of latent heat energy storage systems. One such system, composed of a cylindrical container filled with paraffin wax, through which a copper pipe carrying hot water is inserted, is presented in this paper. It is shown that the physical processes encountered in the flow of water, the heat transfer by conduction and convection, and the phase change behavior of the phase change material can be modeled numerically using the finite element method. Only charging (melting) is treated in this paper. The appearance and the behavior of the melting front can be simulated by modifying the specific heat of the PCM to account for the increased amount of energy, in the form of latent heat of fusion, needed to melt the PCM over its melting temperature range. The effects of adding fins to the system are also studied, as well as the effects of the water inlet velocity.Copyright

PREDICTIVE MODEL FOR WILD BLUEBERRY FRUIT LOSSES DURING HARVESTING

This study provides an economic and energy analysis of the implementation of geothermal systems to meet the needs of a typical 130 m2 dwelling of a Canadian individual. The objective is to determine the monetary balance after 22 years, the net present value, the internal return rate, and annual savings for the same system operating under different climatic conditions and in different provinces (legislations, costs of fuel) to determine whether or not an individual should implement such a system in 2014. The geothermal system is used for both space heating and cooling, and to provide for 25% of the total amount of domestic hot water. The simulations are performed with RETScreen® for four Canadian cities: Halifax, Montreal, Toronto, and Vancouver. For the investigated configurations, it appeared that the cost of energy and its sources, which varied greatly according to the location, are the factors that most strongly influenced the economic viability of the proposed geothermal system, while climate was only...

Development and Performance Testing of a Light Source System on a Smart Sprayer for Spot-Application of Agrochemical in Wild Blueberry Fields

In Canada, space heating and cooling accounts for 55 percent of the total energy consumption in the commercial sector (Natural Resources Canada, 2016). Efficiency improvement in this area using energy storage could have a significant impact on the total energy demand. Phase change materials (PCMs) have been shown to be a viable medium for thermal energy storage having larger storage capacity per mass then conventional sensible heat storage materials. However, they generally have low thermal conductivity producing low heat transfer rates, resulting in relatively slow charging and discharging of the material. This paper will discuss the characterization of an air-PCM storage design for commercial air handling unit (AHU) applications during winter.

Characterization of Thermal Interface Materials Using a Steady State Experimental Method

Abstract. Wild blueberries are one of the most important fruit crops of Canada, producing more than 50% of the world’s production. Understanding and predicting the relationships between the machine operating parameters, fruit losses, topographic features and crop characteristics can aid in better berry recovery during mechanical harvesting. This paper suggested a modeling approach for prediction of fruit losses during harvesting using artificial neural network (ANN) and multiple regression (MR) techniques. Four wild blueberry fields were selected and completely randomized factorial (3 x 3) experiments were constructed at each site. One hundred sixty two plots (0.91 x 3 m) were made at each site, in the path of operating harvester. The total fruit yield, total losses were collected from each plot within selected fields. The harvester was operated at specific levels of ground speed (1.20, 1.60 and 2.00 km h-1) and head rotational speed (26, 28 and 30 rpm). The readings of slope, plant height, and fruit zone were also recorded from each plot. The collected data were normalized, and 70% of the data were utilized for training, and 30% for validation of the developed models using ANN and MR techniques. The developed models were validated internally and externally and the best performing model was identified based on mean square error (MSE), root mean square error (RMSE), coefficient of efficiency (CE) and coefficient of determination (R2). Results of scatter plot among the RMSE and epoch suggested that an epoch size of 15000 was appropriate to process fruit losses using ANN approach. Results revealed that the prediction accuracy of the MR models was lower (R2 = 0.46; RMSE = 0.14) than the ANN model (R2 = 0.84; RMSE = 0.075) for training dataset, which might be due to the non-linear nature of the data. Results reported that the ANN model predicted fruit losses with higher (R2 = 0.63; RMSE = 0.11) accuracy when compared with MR model (R2 = 0.37; RMSE = 0.15) for external validation dataset. Overall, the results of the study suggested that the ANN model was able to predict fruit losses accurately and reliably as functions of fruit yield, crop and machine variables. This study will help to identify the factors responsible for fruit losses and to suggest optimal harvesting scenarios to improve berry picking efficiency and recovery.

Near-field mixing in turbulent free jets issuing from triangular orifices with different apex angles

Abstract. Wild blueberry producers occasionally are required to apply agrochemicals during the early morning, evening or after dark with low wind conditions. The objective of this study was to develop an artificial light source system that could be added to a smart sprayer to allow cameras to detect target areas in the field with low ambient light conditions. The design requirements were a rugged construction that gave an even light distribution under an entire 12.2 m machine vision sensor boom. Polystyrene diffuser sheets were used to eliminate the hot spots created by the lights. A lux light meter was used to determine the light intensity at 0.3 m spacing on the ground under the camera boom with zero ambient light. A field test was completed in a wild blueberry field in central Nova Scotia, Canada to test the developed light source system with low natural light conditions. A real-time kinematics-global positioning system was used to map the boundary of the test track, selected bare soil areas, weed areas and wild blueberry plant areas in the field. The smart sprayer and light source system was driven across the test track several times using different combinations of camera and image processing settings to determine the optimum values for use with the developed light source. Spray percent area coverage on water sensitive papers placed in bare soil and blueberry patches were 22.34% and 25.79% lower than in weed patches, respectively. Spray savings of 65% was obtained using the smart sprayer for spot-application on weeds.