Ali Hakkaki-Fard

• PhD
• Professor (Associate) at Université Laval

A green hydrogen production method based on solar energy is proposed, and Machine Learning (ML) models are adopted for system optimization. This study assayed to highlight the potential of using ML in anticipating the performance of a Photovoltaic Thermal (PVT) system integrated with an electrolyzer device. For this purpose, the performance of four...

This contribution scrutinizes the performance of the integrated photovoltaic thermal (PVT) system with the proton exchange membrane methanol electrolyzer (PEMME) and water electrolyzer (PEMWE) as sustainable ways to produce hydrogen. Artificial neural networks (ANNs), are adopted to evaluate the effect of various operating parameters on the perform...

The solar-driven humidification-dehumidification desalination system with a geothermal dehumidifier (SD-HDH-GD) has been given special attention, especially for subsurface irrigation. This contribution scrutinizes the performance of the geothermal dehumidifier of the SD-HDH-GD system. To this aim, a comprehensive three-dimensional transient computa...

In the current research, a three-dimensional photovoltaic thermal system integrated with phase change material system with nanofluids is investigated. The working fluids involved in this study include nano-magnesium oxide, multiwall carbon nano tube and hybrid (mixture of nano-magnesium oxide and nano-multiwall carbon nano tube) nanofluids disperse...

The solar humidification-dehumidification desalination system with a subsurface condenser is a promising and sustainable approach to providing a sustainable water supply. In this study, a comprehensive three-dimensional transient computational fluid dynamics model of the system is developed. Due to the lack of an experimental study on the thermal p...

The solar humidification-dehumidification desalination system with a subsurface condenser is a promising renewable energy-based desalination system. This desalination system is particularly suitable for condensation irrigation in greenhouses, especially where conventional energy sources are limited. A computational model of the system comprising a...

Solar-driven ejector refrigeration (SER) systems have been granted special attention as a green and sustainable replacement for conventional vapor compression cooling systems. However, despite their significant advantages, SER systems suffer from a relatively low coefficient of performance and failure at high ambient temperatures and low solar radi...

The pile foundation designed to ensure building stability when equipped with heat exchanger pipes to harvest geothermal energy is called an energy pile. Ground Source Heat Pump (GSHP) systems combined with energy piles have been used and developed as sustainable and efficient HVAC systems. Energy piles suffer from cold or heat accumulation in and a...

Horizontal Ground Heat Exchangers (HGHE) as a means of exploiting geothermal energy has come to the fore for a few decades. Various analytical and Computational Fluid Dynamics (CFD) methods have been proposed to predict the performance of the HGHEs. The available analytical approaches are fast; however, they are based on various simplifications and...

In this study, the performance of a Photovoltaic Thermal-Organic Rankine Cycle (PVT-ORC) system combined with a Proton Exchange Membrane Electrolysis Cell (PEMEC) is investigated. A combined numerical/theoretical model of the system is developed and used to evaluate the effect of various system design parameters. In addition, the effects of using w...

As one of the cleanest energies, hydrogen has attracted much attention over the past decade. Hydrogen can be produced using water electrolysis in a Proton Exchange Membrane Electrolysis Cell (PEMEC). In the present study, the performance of the PEMEC, powered by the Photovoltaic-Thermal (PVT) system, is scrutinized. It is considered that the PVT sy...

Solar Chimney (SC) can play a significant role in energy consumption reduction of ventilation applications. The primary purpose of this study is to ameliorate the performance of an inclined rooftop SC integrated with the Phase Change Material (PCM) and Photovoltaic (PV) module, called the SC-PCM-PV system. To this aim, the effects of using finned a...

Pool boiling heat transfer as a promising heat transfer mechanism that can provide ample heat dissipation for thermal management applications has been granted much attention. This study puts forward the idea of applying an Inner Corrugated Hollow Conical Frustum (ICHCF) to ameliorate pool boiling heat transfer. The performance of the ICHCF is exper...

Ground Source Heat Pumps (GSHP), as a renewable source heating, ventilating, and air conditioning (HVAC) technology, has the highest energy efficiency among different heat pump types. One of the major drawbacks of GSHPs is the long-term ground temperature variations as a result of heat accumulation or depletion in the ground. This contribution puts...

In an attempt to prolong the performance of the conventional Solar Chimney (SC) and enhance its efficiency, this contribution presents a kind of novel compound SC with the Photovoltaic (PV) module and Phase Change Material (PCM) called the SC-PV-PCM system. Using PCM not only improves the PV module performance but also extends the productive period...

Plate ground heat exchangers (GHEs) are renowned for having the highest heat transfer rate per unit land area and could be of interest when the accessible land area is limited. In this study, a 3-D numerical model is developed to investigate the thermal performance of vertical plate GHEs at the real-scale level. The proposed model accounts for ambi...

Natural convection heat transfer in a concentric horizontal annulus with annular fins is numerically studied. Due to the low thermal conductivity of water, CuO-water and Al2O3-water nanofluids were used as heat transfer fluids. The effect of three different parameters, including fin spacing, fin eccentricity, and fin thickness at different fin diam...

Ground-source heat pumps have received much attention due to their high coefficient of performance. In these systems, the ground is used as a sink/source for the heat pump, and the heat transfer between the ground and the heat pump is performed by the ground heat exchanger. In this study, the long-term performance and initial cost of these systems...

The application of incinerators for the municipal solid waste (MSW) is growing due to the ability of such instruments to produce energy and, more specifically, reduce waste volume. In this paper, a numerical simulation of the combustion process with the help of the computational fluid dynamics (CFD) inside a portable (mobile) incinerator has been p...

As a versatile platform for integrating renewable energies, District Heating systems (DHSs) offer a pragmatic approach toward an environmentally benign and sustainable future. This paper puts forward the feasibility evaluation of using geothermal hot spring source Heat pumps (HPs) for district heating of a village situated in the north-west of Iran...

In the current research, a three-dimensional photovoltaic thermal system integrated with phase change material system with nanofluids is investigated. The working fluids involved in this study include nano-magnesium oxide, multiwall carbon nano tube and hybrid (mixture of nano-magnesium oxide and nano-multiwall carbon nano tube) nanofluids disperse...

In this work, a three-dimensional numerical model is developed to investigate the performance of a photovoltaic thermal system integrated with a thermoelectric generator module (PVT/TE). Furthermore, the effects of various operating parameters such as solar radiation, coolant mass flow rate, and inlet and ambient temperatures on the performance of...

Ground-coupled ejector cooling (GCEC) systems have been introduced to solve the air-coupled ejector cooling (ACEC) systems problems. To date, no research study is dedicated to compare the GCEC and the ACEC systems and determine the relative payback period of the GCEC system vs. the ACEC system. Furthermore, almost all the previous studies simulated...

Horizontal ground heat exchangers (GHEs) have a lower initial installation cost in comparison to vertical ones; however, they require more land area. In order to reduce the required land area of horizontal GHEs, their heat exchange rate per unit land area needs to be enhanced. A remedy to this problem is installing horizontal GHEs in an arrangement...

Horizontal ground heat exchangers (GHEs) have a lower cost in comparison to vertical ones; however, they require more land area. For the sake of reducing the required land area for horizontal GHEs, flat-panel GHEs have been recently introduced. In this piece of research, a 3-D numerical model has been developed to predict the thermal performance of...

The pool boiling is one of the heat transfer mechanisms used in cooling systems. Using an external force to improve the efficiency of thermo-fluid systems is among the most effective approaches, and also highly applicable in enhancing heat transfer. In this study, the pool boiling of water, as the working fluid, in the presence of a variable magnet...

High mountains and cold climate in the north-west of Iran are critical factors for the design of optimized District Heating (DH) systems and energy-efficient buildings. It is essential to consider the Life Cycle Cost (LCC) that includes all costs, such as initial investment and operating costs, for designing an optimum DH system. Moreover, consider...

Ejector refrigeration system has many advantages over traditional compressor-based systems, including: simplicity, low installation and operating costs and the ability to operate with low-grade thermal energy sources. However, its main drawbacks are low Coefficient of Performance (COP) and failure at high ambient temperatures. To overcome these pro...

In this paper, a comprehensive three-dimensional model of photovoltaic thermal system integrated with phase change material (PVT/PCM) is developed and simulated. The effect of some key parameters using parametric analysis on performance of PVT/PCM system with water as working fluid is investigated. Parameters considered in this study include the pr...

Heat pumps as the only end-use cooling/heating technology with a Coefficient of Performance (COP) greater than one, have attracted a great deal of attention over the past decade. In this study, the long-term energy and exergy analysis of four different types of heat pump systems: a common Air Source Heat Pump (ASHP), an ASHP with Ground Air Heat Ex...

Dust deposition on the surface of solar systems is one of the main parameters that significantly affects the performance of such systems. In this study, the effect of dust deposition density on the performance of photovoltaic modules (PV) and photovoltaic-thermal systems (PVT) is numerically investigated. Accordingly, all layers of a monocrystallin...

The aim of the present study is to investigate the uniform cooling of a hot isothermal heated target surface, using four turbulent impinging air jets. Eight parameters including the width of jets, the space between the inner jets, the space between inner and outer jets, the distance of jets from the plate, the impingement angle of jets and the over...

In recent years horizontal Ground Heat Exchangers (GHEs) has attracted a growing interest as heat source/sink for ground source heat pump systems. Horizontal GHEs initial installation costs are lower than the vertical ones; however, they require larger land area and more pipes. Therefore, it is necessary to reduce their required land area and pipe...

The boiling phenomena in a quiescent fluid is the nucleate pool boiling which has attracted much interest in the thermal management studies. This paper investigates the effect of the installed Twisted Tape Fins (TTFs) on the heat transfer from a surface with a temperature above the water saturation point to a coil condenser. Four different arrangem...

Despite interesting potential for heat recovery and efficiency improvement that supersonic ejectors can bring to energy consuming systems, their successful use in industrial applications strongly depends on high performing designs. In order to reach this objective, an attempt is made to bridge the gap between available performance enhancement techn...

The ejector technology has the potential to significantly improve the energy efficiency of various processes. However, successful utilization of an ejector into an industrial system requires the knowledge to come up with an ejector design leading to high performance. To increase our comprehension of ejector operation, a prototype allowing the measu...

This study aims to compare two commonly used ASHP (air-source heat pump) and DX-GSHP (direct-expansion ground-source heat pump). There have been many debates on energy efficiency, system costs and relative payback period of DX-GSHP against ASHP systems over the past few years. In this context, and with the aim of enriching this debate, a detailed s...

Heat pumps (HP) are one of the most adapted heating solutions for meeting low energy consumption requirements of buildings. However, improving the performance of the heat pumps at low ambient temperatures is still an open challenge. This paper assesses the potential benefits of implementing zeotropic refrigerant mixtures in residential air-source h...

Heat pumps are currently considered as one of the most promising means for meeting low energy consumption requirements in buildings. However conventional air source heat pumps suffer from severe limitations in terms of performance at low ambient temperatures, while new designs such as multi-stage compression or ground source heat pumps are still ve...

Heat pumps represent the only end-use heating technology that has coefficient of performance greater than one. However, the efficiency of air-source heat pumps decreases drastically at low cold source temperature which represents a higher barrier to their adoption in cold climates. The use of mixtures of refrigerants with the aim of increasing the...

In the unsteady process of shock reflection off convexly curved surfaces, the Reynolds number can have an influence on the development of the irregular reflection pattern. Time-resolved visualizations of the reflection process and high-resolution numerical simulation are used in this investigation to quantify this influence, which manifests itself...

Heat pumps, as a means of achieving significant energy reductions, have attracted a great deal of attention for decades. However, the main challenge remains improving their performance in cold climates. This paper represents the first step of a larger research project for the implementation of the zeotropic refrigerant mixtures in order to increase...

The transition from so-called regular to irregular shock wave reflection has been the subject of considerable research effort over the last seven decades [1]. The most thoroughly investigated case is that of the straight wedge

In this paper, three techniques for determination of the sonic/catch-up points in unsteady shock reflections based on numerical flowfield analysis are considered: the Mach-number-based technique, the characteristic-based technique, and the perturbation technique. These techniques are compared using the problem of shock reflection from a convex cyli...

A novel numerical approach is proposed for determination of the surface conditions of ablative materials that can be considered as a counterpart of previous studies. The proposed technique benefits from the Euler solver that calculates the flowfield outside the boundary layer. The Euler solver is coupled with the charring material ablation code tha...

When a moving shock wave encounters a convex cylinder, reflects from it regularly, and propagates further, at one particular shock position corresponding to the so-called sonic point the flow on the cylinder’s surface, just behind the reflected shock becomes sonic with respect to the moving reflection point. The sonic point is prominent in the theo...

Ablative materials can sustain very high temperatures in which surface thermochemical processes are significant enough to cause surface recession. Existence of moving boundary over a wide range of temperatures, temperature-dependent thermophysical properties of ablators, and no prior knowledge about the location of the moving surface augment the di...

Estimation of heat flux in the nonlinear heat conduction problem becomes more challenging when the material at the boundary loses its mass due to phase change, chemical erosion, oxidation, or mechanical removal. In this paper, a new gradient-type method with adjoint problem is employed to predict the unknown time-varying heat flux at the receding s...

In this article, nine ablative parameters of ablative composites are estimated using nonlinear inverse methods. The mathematical model of the ablative composite when exposed to a thermally harsh condition has been developed on the basis of the decomposition of the resin and formation of the char layer at a critical temperature. Three zones of virgi...

The modified Levenberg-Marquardt method is used for simultaneous estimation of decomposition kinetic coefficients and temperature-dependent thermophysical properties of charring ablators with a moving boundary over a wide temperature range. No prior information is used for the functional forms of the unknown thermal conductivity and specific heat....

The limitation of the experimental methods in thermophysical characterization of composite materials leads to an increased use of inverse parameter estimation techniques. However, in some situations the convergence of the inverse algorithm is impossible due to the correlation of the involved parameters and the existing noises in measurement data. S...

In this work, the prefiltering of the sensor data is taken into consideration when solving an inverse heat conduction problem. The temperature data obtained from each sensor is considered as a discrete signal, and discrete wavelet transform in a multi-resolution filter bank structure is utilized for the signal analysis, after which wavelet denoisin...

This article addresses numerical modeling of coupled heat conduction and radiation in mineral wools under steady-state condition for prediction of its effective thermal conductivity. The radiative heat transfer is modeled using the Monte Carlo Ray-Trace Method. The radiation model is based on a random distribution of fibers in the media. The radiat...

Relationship between thermal conductivity (λt) and density (ρ) of mineral wool insulations has a wide band of measured data, follows some form of median curve which is called reference curve. Departures from this curve are mainly due to the fact that manufacturing conditions change. But the deviation from the curve should be in a limited range beca...

The limitation of the experimental methods in determining the thermal conductivity due to the air/fiber conduction in mineral wools leads the use of inverse parameter estimation techniques. However, in some circumstances, the convergence of the inverse solution is impossible due to the correlation of the involving parameters and the existing noises...

The Levenberg-Marquardt method is used for simultaneously estimating the temperature-dependent thermal conductivity and specific heat of noncharring ablators with moving boundary over a wide temperature range up to 5000 K. It is assumed that no prior information is available on the functional forms of the unknown thermal conductivity and specific h...

This article presents a novel methodology, which is highly efficient and simple to implement, for simultaneous retrieval of a complete set of thermal coefficients in combined parameter and function estimation problems. Moreover, the effect of correlated parameters on convergence performance is examined. The present methodology is a combination of t...

Purpose – The purpose of this paper is to reduce the destructive effects of existing unavoidable noises contaminating temperature data in inverse heat conduction problems (IHCP) utilizing the wavelets. Design/methodology/approach – For noise reduction, sensor data were treated as input to the filter bank used for signal decomposition and implementa...

The conjugate gradient method with adjoint problem is applied in the present study to estimate an unknown heat flux function at the surface of an ablating insulator. The ablation process is modeled as having two processes of ablation and thermal degradation simultaneously; therefore, two zones, virgin and char layers and two moving boundaries, abla...

This article investigates the applicability of inverse methods in estimating the best values to be assigned to certain parameters which appear in turbulent flow studies of dilute polymer solutions in circular pipes. These parameters naturally arise when the Nagano-Hishida low-Re, k-ε model is combined with a special form of the Generalized Newtonia...

In this article, natural convection in a square porous enclosure is simulated by a direct numerical method. The solution method is based on a random distribution of solid blocks, which resembles the porous media within the cavity. The Navier–Stokes equations are solved directly in the fluid region without the assumption of volume averaging. The no-...

The conjugate gradient method with adjoint problem is applied in the present study to estimate an unknown heat flux function at the surface of an ablating insulator. The ablation process is modeled as having two processes of ablation and thermal degradation simultaneously, therefore, two zones, virgin and char layers and two moving boundaries, abla...

For load-bearing mineral wool insulations, compressive stress at 10% deformation is an important property which is studied as a function of density. The determination of compressive behavior of insulations is not a simple and fast test procedure. However, it can be estimated with indirect test method of determination of density which is simple and...