Showing papers by "Arash Karimipour published in 2022"

Phase change material dependency on solar power plant building through examination of energy-saving

Abstract: In this study, the effect of phase change material on walls and roof considering solar intensity was discussed. Due to the geographical location of the city of Jeddah in Saudi Arabia, the effect of installing phase change material within thicknesses of 1–10 cm in the period from April 1 to September 30 was investigated. Numerical results showed that if phase change material is added to the roof (at 1 cm), the heat transfer not only did not decline but also increased. However, for the walls in the main directions, phase change material (at 1 cm) was useful. Based on the results, the western wall was the most sensitive wall to phase change material presence so that the addition of phase change material at 1–5 cm resulted in energy-saving by 2.4–7.2 kWh/m2. Although phase change material at a thickness of 1 was not useful for the roof, at thicknesses of 2–5 cm, the presence of phase change material reduced the energy exchange by 1.21–33.8 kWh/m2. Finally, it was found the best results are obtained by adding phase change material for the western wall and roof. Examining the energy-saving for building by adding phase change material, it was found that adding phase change material with thickness up to 5 cm is recommended. Further increase in thickness reduces the positive effects of phase change material.

Examining the effects of interior setpoint temperature on phase change materials usefulness through a performing annual analysis in the air handling units: A building energy management study

Abstract: Places such as Saudi Arabia has a desert climate and therefore in most households, air conditioning is used. This country ranked 4th in the world from the perspective of using air conditioning. In 2018, the total electricity demand in residential buildings was 130 TWh and the share of cooling was 66%. In this study, by adding phase change materials to the wall to reduce the cooling load, electricity demand variations were examined. The results showed that the effects of phase change material on the cooling loads depends on the difference in melting temperature and interior setpoint temperature (Tmelting-Tsetpoint). Therefore, several phase change materials (A27, A28, A29 and A32) were selected with different melting temperatures (27–32 °C). An air handling unit was used to adjust the interior temperature at the setpoint within 21–31 °C. The best performance was corresponded to Tmelting-Tsetpoint = 2 °C. In other words, if the melting temperature of phase change material is higher than the setpoint by 2 °C, the phase change material performance will be maximized. Under this condition, the cooling load experienced the greatest reduction. At Tmelting-Tsetpoint = 2 °C, adding phase change material A27 reduced cooling load by 19,515 kWh. This figure for A28, A29 and A32 was 27,538, 25,034 and 33,905 kWh, respectively.

Energetic thermo-physical analysis of MLP-RBF feed-forward neural network compared with RLS Fuzzy to predict CuO/liquid paraffin mixture properties

Abstract: ABSTRACT Dynamic viscosity of novel generated Copper Oxide (CuO)/Liquid Paraffin nanofluids is obtained experimentally for various temperatures and concentrations. To optimize the empirical process and for cost-efficiency, Feed-Forward Neural Networks (FFNNs) were modeled and compared with Recursive Least Squares (RLS) Fuzzy model. To prepare CuO/ liquid paraffin nanofluids, CuO nanoparticles are dispersed within paraffin. Then an input-target dataset containing 30 input-target pairs is available for , and . Based on the empirical results, two types of FFNNs are examined and compared with RLSF model to predict CuO/liquid paraffin nanofluids. To evaluate the best optimization methods of nanofluid viscosity, Multi-Layer Feed forward (MLF), Radial Basis Function (RBF), and RLSF are compared and discussed. The MLF network provides a global approximation while the RBF acts more locally, further, RLSF provides a better fit. On the contrary, the RBF network has better properties from the generalization and noise rejection points of view. Also, RBF networks can be applied in an online manner. Further, three curves of RLS Fuzzy model by Parabola2D, ExtremeCum, and Poly2D models were fitted on the empirical data and compared. The ExtremeCum model showed the least margin of error and can be employed to predict the data.

Reducing electricity demand by integrating a sustainable pack into HVAC- adding PCM in sustainable pack as well as building envelopes

Abstract: This article proposes two solutions focusing on reducing energy consumption in air handling unit (AHU). The first solution introduces a sustainable pack consisting of a ground heat exchanger (GHE) and two PCM-filled heat exchangers (PCMHE). In the sustainable pack, two PCMs are used to boost the chance of providing cold water. The cold water leaving the sustainable pack is directed to the AHU to cool the incoming fresh air. By integrating the sustainable pack, energy usage was reduced by 4512 Wh/m2 resulting in a 32% reduction in CO2 emissions. In the second solution, PCM was used to reduce energy exchange and it was observed that in the hottest month, the indoor surface temperature cools down by 1.3 °C. Owing to lower energy usage, CO2 emissions declined by 50% than that of buildings without PCM/sustainable pack. Effects of PCM were dependent on the PCM volume fraction, especially at lower volume fractions. At volume fractions of 10% and 20%, the amount of energy consumption was 6979 and 1430 Wh/m2. With increasing the volume fraction of PCM to 30, 40 and 50%, no significant change in energy consumption was observed.

Introducing a new PID controller to control the addition of PCM to the building with ventilation heat recovery installation to reduce the energy demand of the cooling system

Abstract: Installation of Proportional-integral-derivative (PID) controllers in air conditioners regulates the hot/cold fluid flow in hot/cold coils, and consequently, maintenance, energy consumption and initial costs are lowered due to reduced coil capacity. In this research, the thermodynamic analysis of an air handling unit was investigated. The thermodynamic energy equations for AHU were developed in TRNSYS software. The temperature and humidity of the ambient air were incorporated into the software. Then, by defining the characteristics of heating and cooling coils, the air handling unit was simulated. To adjust humidity a heating coil along with several differential controllers were installed prior to the supply air duct. The simulation results showed that the air handling unit can provide suitable thermodynamic conditions in the interior space (22 °C and 55%). To provide ventilation conditions, AHU consumed 602 kWh/m2 per year. Due to the thermodynamic conditions inside the building, suitable conditions were provided for the air conditioner to use heat recovery and it is found that energy utilization in AHU coils dropped by 43.2%. Moreover, PCM was added to the building in two locations, the innermost layer and the outermost one. While the building took advantage of heat recovery, PCM in the outermost layer still managed to reduce AHU power utilization. However, due to the phase change temperature and the indoor temperature, if PCM is installed in the innermost layer, its performance will be slightly better.

Using PCM for building energy management to postpone the electricity demand peak load and approving a new PID controller to activate alternative chiller

Abstract: In this study, PCM was used to delay the maximum heat transfer and postpone it to a low load time in a building. Hence, a new proportional–integral–derivative (PID) controller system was introduced that could adjust the temperature using six setpoints . To evaluate PCM performance accurately, a 5 cm layer of PCM was added to the wall and instead, the thickness of Thermalite Turbo (which had the highest heat resistance) was reduced by 5 cm to keep the final wall thickness constant . The energy equation for indoor space was approved and by considering the PCM phase change along with radiation effects, the temperature distribution within the wall was obtained. The PCM inside the wall during January–June lessened electricity demand but raised it slightly in the remaining months. However, in the annual analysis, PCM managed to reduce electricity demand by 15.3%. To compensate for poor PCM performance during summer, a PID control system disconnects the main chiller and adds an alternative chiller to the circuit. Using new PID system led to an electricity demand reduction of 2.2%. According to the schedule, electricity consumption decreased by 2.3%. • Approving a new PID controller to activate alternative chiller. • PCM for building energy management to postpone electricity demand peak load. • Using new PID system led to an electricity demand reduction of 2.2%.

Thermal management of a battery pack using a layer of phase change material around the batteries: Changes in the airflow through the battery

Abstract: In this paper, a battery pack with 27 lithium-ion cylinder batteries is simulated in two dimensions. This consists of 3 rows of 9 batteries. All batteries are made of phase change material, which is placed in a circular chamber. There is airflow at the Reynolds number ranging from 100 to 400. Temperature, airflow, the volume percent of molten phase change material, the highest and average temperatures of the battery pack, ambient air temperature, and volume fraction are all measured from 0 to 3000 s in this research. COMSOL Multiphysics 5.4 software is used for numerical analysis. The results demonstrate that the ambient air temperature at Reynolds number = 100 does not control the temperature of the battery and its temperature has an increasing trend. Also, the temperature of the output air from the battery pack is reduced with the Reynolds number. At 3000 s, the molten phase change material at Reynolds number = 400 is 30.74% lower than that at Reynolds number = 100. At all values of Reynolds number, enhancing the time reduces the amount of molten phase change material.

Transforming Conventional Construction Binders and Grouts into High-Performance Nanocarbon Binders and Grouts for Today’s Constructions

Abstract: The transformation of conventional binder and grout into high-performance nanocarbon binder and grout was evaluated in this investigation. The high-performance nanocarbon grout consisted of grey cement, white cement, lime, gypsum, sand, water, and graphite nanoplatelet (GNP), while conventional mortar is prepared with water, binder, and fine aggregate. The investigated properties included unconfined compressive strength (UCS), bending strength, ultrasound pulse analysis (UPA), and Schmidt surface hardness. The results indicated that the inclusion of nanocarbon led to an increase in the initial and long-term strengths by 14% and 23%, respectively. The same trend was observed in the nanocarbon binder mortars with white cement, lime, and gypsum in terms of the UCS, bending strength, UPA, and Schmidt surface hardness. The incorporation of nanocarbon into ordinary cement produced a high-performance nanocarbon binder mortar, which increased the strength to 42.5 N, in comparison to the 32.5 N of the ordinary cement, at 28 days.

Lithium-ion batteries investigation regarding different fins distribution associated electrochemical effects and various voltage types

Abstract: The passive heat control system of a battery connected to a solar system using materials with phase change materials is investigated. The effect of fins with peak and valley configurations on cylindrical lithium-ion batteries is assessed. In this study, the temperature distribution on the battery is determined by solving the thermal equations of the battery and using the previous references. Then, the fins and their configurations on the battery are determined by using the temperature distribution. These configurations are in the form of maximum length on the center and maximum length on the sides of the battery. The effect of the distance of the fins in different configurations is investigated. For this purpose, the solution is done using the finite element method. The simulation results show that the maximum amount of battery temperature occurs in its middle. The use of shorter fins enhances this and also reduces the volume fraction of molten phase change materials for a long time. Using this cooling method, the blade along with the phase change materials improves the performance of the charging process in a solar system.

Thermal management of a lithium ion battery pack connected to a solar panel using a comparison of two cavities filled with phase change materials: Oval and rectangular

Abstract: In this paper, the temperature of three 18,650 lithium-ion battery cells in an air duct is studied using a numerical method. The batteries are housed in a PCM pack with two different oval or rectangular shapes. This battery pack and PCM are placed in the air duct with (Re) 50 or 150. The aim of this study was to investigate the temperature of all three battery cells, the maximum temperature (T-MX) of the battery cells and the amount of frozen PCM at different times. For this study, help was obtained from Comsol software. The results of this study showed that the use of battery pack and PCM in the shape of an ellipse, compared to the rectangular shape caused a lower temperature on all battery cells. Also, the use of PCM ellipse pack has resulted in lower average and T-MX for the battery cell and more solid PCM volume fraction than the rectangular shape of PCM pack. Using (Re) 150 instead of 50 causes the battery cell temperature to be much lower and also the amount of solid PCM to be higher. The (Re) change in airflow, as well as the shape of the battery pack and PCM, affects the first battery cell more than any other battery cell.

The investigation of battery thermal management via effects of using phase change materials in the oval packages around the lithium-ion battery cells with an airflow

Abstract: Due to the ability of phase change materials (PCM) in heat storage and thermal management system (TMS) of various devices, in this paper, the numerical study of the effect of using these materials on TMS of lithium-ion batteries was studied. There is also airflow in the battery pack (BAP) to control the battery temperature (T-B). Around the batteries, CaCl2.6H2O phase change agent was used in oval packages to control the T-B. A transient study performed for the time after melting, 100 %. PCM, which cools the airflow and CaCl2.6H2O at the same time as the battery is running, so that the amount of molten PCM is reduced so that the PCM can control the T-Bs again. The T-Bs was also monitored by establishing a space between the rows of batteries. The numerical analysis was carried out using the finite element technique and the COMSOL program. The findings revealed that the volume fraction (VLF) of PCM melt surrounding the batteries reduced with time. The decrease in melt PCM was significant in the first column but had little effect in the third column. Changing the vertical distance of the batteries from each other in the third column of batteries is very effective, while in the first column has little effect on the temperature and VLF of PCM. At a distance of 7 mm from the battery rows, there is the highest amount of T-B and molten PCM. The lowest T-B pack and molten PCM occurs at a distance of 9 mm from the battery rows.

Improve the rheological and thermal performances of the antifreeze liquids for cooling the batteries and radiators in automobiles via provide a new hybrid material composed from Carbon Nanotubes in Ethylene Glycol/Propylene Glycol

Abstract: A new antifreeze hybrid nanofluid is developed in the present study. The hydrodynamic and thermal properties of the base fluids, such as water and Ethylene glycol are improved via examining the Nanoparticles. The final achieved nanofluid will be used for the cooling batteries; however, it might be applied for similar mechanical/ electrical systems such as through the radiators. The Carbon nanotubes are examined as dispersed nanoparticles. At first, an experimental part of producing the new mixture involving homogenizing and predicting the thermo-physical properties is presented. The numerical section will be reported regarding the heating/cooling simulations for the batteries. The proposed nanofluid in battery cooling systems dropped the battery temperature in different conditions. To investigate the effects of nanofluids, the energy equation was solved along with the energy source term arising from electrochemical reactions and ohmic losses. The temperature distribution inside the battery indicated a reduction in the maximum battery temperature when CNT nanoparticles were loaded. At a 50% state of discharge, the average battery temperature was 5.8°C lower when nanoparticles were CNT was loaded into EG + W. As the amount of state of discharge increased, the effect of the CNT presence intensified so that at a level of 95%, the temperature dropped by 6.9°C.

Using proportional-integral-derivative controllers and PCM and a new design of building air intake with five scenarios to present a multi-zone CAV-AHU for tackling high energy consumption

Abstract: Meet the requirements of regulating temperature, humidity and fresh air inside the buildings is not cost-effective due to high energy consumption (EC). In this study, a control system based on proportional-integral-derivative (PID) controllers was installed for mixing the supply air and return air in two strategies including installing phase change material (PCM) and a new layout for air intake from the return air were introduced for a constant air volume air handling unit (CAV-AHU). Considering a setpoint of 25 °C, the reference CAV-AHU was devised by the summer multiple design months technique, and it was observed that it is not likely to satisfy the setpoint requirement all the time. The first strategy was implemented, and it was found that although the final energy consumption declined by 15.3%, indoor temperature distribution was not acceptable. To regulate the indoor temperature, five scenarios were defined in which the share of return air utilization was variable. Establish the first scenario in a system that uses PCM provides less energy consumption by 177 Wh/m 2 and better internal temperature distribution. In the second, third and fourth scenarios, the final energy consumption was reduced by as much as 404, 638 and 905 Wh/m 2 . In the best-case scenario (fifth), not only energy consumption reduction of 1277 Wh/m 2 (5.5% reduction) was achieved but also the setpoint requirement was met. The addition of PCM and the variable share of return air utilization let the designer to design a lower rated power CAV-AHU (by 33%), thus reducing the initial investment cost and, in addition, the final energy consumption of the modified CAV-AHU is lower by 20%. • Develop a new design of building air intake with five scenarios. • Using proportional-integral-derivative controllers and PCM. • Present a multi-zone CAV-AHU for tackling high energy consumption.

Thermal analysis of battery cells placed in triangular enclosures filled with PCM in the presence of forced airflow in an air duct

Abstract: In this paper, a thermal analysis is performed on battery cells placed in a battery pack using the finite element method . All cells are placed in triangular enclosures filled with phase change material (PCM). The battery pack with PCM enclosures is located in laminar airflow. Two arcs are placed at the inlet to direct the air towards the air duct by changing the angle of the arc. In this study, the phase change of PCM from liquid to solid and the temperature of battery cells in 100 min are examined transiently. The amount of energy produced by the battery for use in the air conditioning system of a house has also been studied. Two-dimensional numerical simulations are performed using COMSOL Multiphysics software. The results demonstrated that the use of the arc with a 90° angle causes the average temperature of battery cells to be minimal. The maximum average temperature of battery cells is observed at the arc angle of 165°. At the arc angle of 90°, the maximum phase change of PCM from liquid to solid is observed. It is also found that the temperature of the battery cells in the first column is minimal and the batteries placed in the middle row of the battery pack are warmer than the ones located in the top and bottom rows of the battery pack. The results also shown that, during the summer, the battery pack can provide up to 66% of the energy needed for the air conditioning system. • Thermal analysis of battery cells placed in triangular enclosures. • Filled with PCM in the presence of forced airflow in an air duct. • Battery pack can provide up to 66% of energy needed for the air conditioning system.

Effect of lithium-ion batteries on heating a residential building using PCM: Changing the horizontal distance between batteries

Abstract: Plate batteries are widely utilized in electronics and telecommunications. Due to the broad application of these batteries, the cooling of two lithium-ion batteries located in an air duct is examined in this article numerically using COMSOL software. Batteries are surrounded by a phase change material (PCM). This study is performed in 10 min by changing the distance between batteries from 2 to 4 cm. The outlet air can be used to heat a building. The finite element method is employed to solve the equations. The findings show a reduction in temperature and a reduction in the quantity of molten PCM (MOP) with an increase in the distance between the batteries from 2 to 3 cm. But when the distance between the batteries is increased by another 4 cm, their temperatures rise and their volume of MOP increases. The minimum and maximum outlet air temperatures correspond to a distance of 2 cm and 3.5 cm, respectively. Most of the energy that can be extracted from the battery cooling system is related to a distance of 3.5 cm between the batteries.

Increasing electricity generation—Installing photovoltaic cells coupled to a battery pack, to provide the electricity

Abstract: By 2050, renewables should increase the share of electricity generation to 70 %. According to the net-zero long-term plan, solar energy is at the forefront of renewable sources. The concreted solar plant is one of the best renewable-based electricity generation utilities that can combine with solar cells and battery systems. In this study, basic modelling for counter flow shell-tube type heat exchanger is developed in which melted salt and steam/water are the two-working fluid of the heat exchanger. A two-phase heat transfer analysis has been considered for the boiling phenomena in the saturated steam region. The study is performed for 5 kg·s −1 flow rate of steam/water and for different flow rate of melted salt varying from 75 kg·s −1 to 300 kg·s −1 . Thermodynamic characteristics of the heat exchanger, such as, vapor quality and convective coefficient variation of the steam/water along the length of the heat exchanger has been presented. In addition, temperature profile of the melted salt and the steam/water along the length of the heat exchanger is determined in this study. Numerical analysis affirmed that the battery cooling was successful at Reynolds number of 200–500 as the maximum temperature was lower 320 K. • Develop a battery basic model of the counter flow heat exchanger. • Examine for cooling via boiling phenomena of melted salt and water. • Thermodynamic characteristics along the length of the battery model.