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Effect of Air-Conditioning on Driving Range of Electric Vehicle for Various Driving Modes
... Auxiliary systems include an auxiliary power unit, a power steering unit, and an air conditioning control unit [9]. If the air conditioner works, the mileage of electric vehicles is significantly reduced: by 35-50% in the cooling mode [10,11] and by approximately 50% in the heating mode [12]. Therefore, these methods are useful for evaluating the efficiency of electric vehicles. ...
... The main parameters in these models are speed and acceleration. At the National Transport University (Ukraine), a study was conducted [29] and nonlinear regression equations were obtained according to the traffic modes: at steady motion (10) and in acceleration mode (11), (12). ...
... where Q R is the fuel consumption in acceleration mode, g/km; and k R is the coefficient of influence of the acceleration mode on fuel consumption (12). ...
The evaluation of the energy efficiency of vehicles in operating conditions is used to solve management and control tasks in intelligent transport systems. The modern world fleet is characterized by an increase in the share of vehicles with alternative power plants (hybrid, electric, and hydrogen fuel cells). At the same time, vehicles with conventional power plants (internal combustion engines) remain in operation. A wide range of modern power plants determines the relevance of studying the advantages and limitations of existing methods of evaluating the vehicle energy efficiency, delineating the application scope and highlighting promising directions for their further development. The article systematizes the methods of evaluation and management of the energy efficiency of vehicles with conventional and alternative power plants. Special attention is paid to the assessment of energy consumption per unit of transport work at the stage of vehicle operation, taking into account various operational factors. The concept of a 3D morphological model of the transport system for evaluating the energy efficiency of vehicles is presented. An algorithm for the optimization of the current transport system configuration according to the criterion of an increase in the energy efficiency indicator is given.
... They are driven by electric motors and are the most energy-consuming auxiliary systems in PEVs. It has been publicly reported that AC systems could reduce the driving (a) Cabin air cooling system (b) Secondary loop liquid cooling system (c) Direct refrigerant cooling system range of PEVs by about 30-40% [58,59]. The energy density of the fuel is much higher than the current battery, and the total efficiency of ICEV is low, so a lot of waste heat is generated. ...
... At present, it is widely used in the PEV market. However, its low efficiency will greatly reduce the driving range of PEV in winter [58,60]. Zhang et al. [61] conducted an experimental study on the steady-state load of PEVs by using the thermal balance method. ...
Zero-emission pure electric vehicles (PEVs) have been progressively developed towards scale production as passenger cars. However, the power, economy, driving range, and other indicators are seriously restricted by onboard batteries. In freezing winter and sultry summer, these problems are greatly aggravated by the energy versus temperature characteristics of the batteries and the turning on of air conditioning (AC). Against this background, three key issues related to thermal management in the development of PEVs: battery thermal management (BTM) technology, cabin thermal management technology (air conditioning system), and integrated thermal management (ITM) technology are proposed. The corresponding advances which are in the embryonic stage are briefly summarized in this paper. By analyzing the cross-functional parts of two auxiliary systems with similar thermal management roles, it is indicated that ITM is the necessary and inevitable way to develop PEVs. ITM can realize the lightweight of PEVs and make up for the shortcomings of each subsystem.
... The use of auxiliary systems may increase the power consumption of the vehicle. It can be estimated for example that the use of air conditioning in a BEV can decrease its autonomy by 33% (Lee et al., 2013). The BEV potential overconsumption of energy has been modeled and tested with air conditioning. ...
... The use of auxiliary systems may increase the power consumption of the vehicle. It can be estimated for example that the use of air conditioning in a BEV can decrease its autonomy by 33% ( Lee et al., 2013). The BEV potential overconsumption of energy has been modeled and tested with air conditioning. ...
The automotive product is increasingly restricted by environmental regulations, including reducing emissions of CO2 and pollutants in exhaust pipes of vehicles. One solution implemented in the automotive industry are plug-in hybrid electric vehicles (PHEV) that use an electric traction battery. To help vehicle manufacturers in their choice of traction battery from an environmental point of view, a simulation method of environmental impacts generated by the use phase is proposed in this paper. This method takes into account the possible usages of the vehicle and potential developments of electric mix, with the formulation of a constraint satisfaction problem (CSP) solved using constraint programming (CP) techniques. The sensitivity of five parameters is investigated: the electricity mix used to charge the battery, the battery mass, electric consumptions, the autonomy in “all-electric mode”, and the share of total travel in “all-electric mode”. Power grid is the most differentiating parameter for global warming and PHEV generates less impact if less used in “all-electric mode” on a high carbon intensity power grid. Lastly, CSP acausal modeling makes it possible to process different simulations with the same model.
... [12] Effects of air-conditioning on the driving range of electric vehicles for various driving modes have also been studied and 33% average decreases in driving range by air-conditioning have been reported. [19] The 37.27% power loss of electric vehicles by using air-conditioning has also been reported. [20] The VIPV is thought to be useful for heat shielding. ...
The development of the vehicles powered by photovoltaic (PV) is desirable and very important for reducing CO2 emissions from the transport sector to realize a decarbonized society. Although long‐distance driving of vehicle‐integrated PV (VIPV)‐powered vehicles without electricity charging is expected in sunny regions, driving distance of VIPV‐powered vehicles is affected by climate conditions such as solar irradiation and outside temperature, and the power consumption of the air conditioners. In this article, analytical results for system efficiency of VIPV‐powered vehicles and the effects of usage of air conditioner are presented by using power losses estimated from the electric mileage by using the driving distance data for Toyota Prius and Nissan Van demonstration cars installed with high‐efficiency InGaP/GaAs/InGaAs three‐junction solar cell modules with a module efficiency of more than 30%. The potential of VIPV‐powered vehicles to be deployed in major cities in Japan and the world is also analyzed. Mild weather cities such as Miyazaki in Japan and Sydney in Australia are thought to have longer driving range even under usage of air conditioners. The other power losses for the VIPV such as temperature rise of VIPV modules and partial shading estimate the previous data and some reference as well as effects of usage of air‐conditioners are also discussed in this article.
... In EVs, PTC heaters were commonly used as a heating element that used high level of energy consumption from battery pack-age in winter conditions and this lead to reduce battery life and also vehicle range in the long term. EV's driving range can be reduced up to 50 % with PTC electric heater due to its low heating efficiency [1]. Moreover, energy management of EVs, is a critical subject due to limitation of energy storage supplied by batteries [2,3]. ...
In this paper, the investigation of the innovative hybrid heat pump system (HHPS) included Positive Temperature Coefficient (PTC) heater commonly used in electric vehicles (EVs) was performed in different heating modes to reach the desired temperature in a target time. The developed HHPS was evaluated in different heating modes in order to reach the desired temperature considering the both target time and also vehicle driving range. It was shown that the driving range can be increased up to 15 % by using HHPS. As a result, a high-capacity PTC heater and HP should be work together at the beginning of the heating, and then the PTC capacity should be reduced gradually at lower ambient conditions. Another important result is that HHPS represent a promising solution for the new generation EVs that the target temperature was obtained lower than 300 s at lower ambient conditions. A numerical model was also developed to investigate the flow and the thermal characteristics of the EV cabin interior that enable to design more effective heating, ventilation and airconditioning (HVAC) systems of EVs under different environmental conditions and the numerical results were in good agreement with the experimental data used in this study. Ó 2023 THE AUTHORS. Published by Elsevier BV on behalf of Faculty of Engineering, Alexandria University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
... Therefore, the power needed by the HVAC system must be taken from the battery. As demonstrated by Lee et al. [1], in general the air conditioning (i.e., cooling and heating) is responsible for about a 33% average decrease in driving range for EVs. ...
Considering the consistent reduction in battery range due to the operation of the Heating Ventilation and Air Conditioning (HVAC) system, this study deals with the CO2 measurement inside the cabin of an electric crane and aims to reduce the energy consumption through the control of the air recirculation. A control strategy was defined and tested through an experimental set-up where the presence of a driver was simulated as a source of CO2. The cabin was placed inside a climatic wind tunnel and the benefits of this control strategy on the HVAC system energy consumption were assessed, both in the heating and the cooling modes. In addition, we discussed the optimal position of the CO2 sensor inside the cabin by comparing the results obtained from some sensors placed around the cabin occupant with the ones logged by three sensors in the breathing zone. Finally, an investigation of the uncertainty of the indirect measurement of the leakage flow and its dependence on the number of CO2 sensors installed in the cabin was made through the Monte Carlo method.
... However, still due to the different configurations, each type of these vehicles has their pros and cons in terms of their corresponding ITMS. In PEV, the ACS, also the most important system for human thermal comfort, is totally electrically powered by the sole power source, i.e. the Li-ion battery [17], leading to a dramatic decrease in the vehicle range, about 30%-40% reduction [18,19]. However, the mileage is no longer an issue in PEMFCV and ICEV since the refuelling of PEMFC and ICE only needs about 3-5 min. ...
Proton exchange membrane fuel cell (PEMFC) vehicles (PEMFCV) have drawn tremendous attention owing to the advantages of low or zero emissions. Effective integrated thermal management systems (ITMS) considering thermal loops coupling and interaction and with a rational strategy are crucial for the efficient and secure operation of PEMFCV. Therefore, ITMS in PEMFCV are worthy to be reviewed comprehensively. This paper aims to provide the general and current ideas of ITMS design in PEMFCV from part-level to system-level, along with control strategies. The factors that affect the thermal performance of heat-generating components and systems are deeply analysed, and the key findings, challenges, and future work are presented. It is found that liquid cooling is more appropriate for ITMS because of the high specific heat and the convenience of integrating other thermal systems, and that heat pumps tend to be a more suitable choice for air conditioning systems. The future work mainly includes the improvement of cooling and cold start of PEMFC, perfection and verification of waste heat recovery system, exploration of new air conditioning systems, integration of systems, coupling of ITMS and energy management systems, and enhancement of model accuracy. The provided information is useful to guide the system layout and control strategies for ITMS at the early design stage.
... It took constant efforts of decades to accommodate new car designs, improve fuel efficiency, gain environmental acceptability, enhance passenger comfort, provide health benefits and increase passenger safety in the HVAC system [39]. The HVAC system consumes a major share of the energy of a vehicle, and with the advent of electric vehicles, studies have shown that it can reduce the driving range of a vehicle up to 40% [40,41]. Hence an appropriate PCM-based thermal management system is the need of the hour as it will not only increase the life of a vehicle and make them more efficient but also will help to curb the emissions and achieve the major goals set up by the global communities to control greenhouse gases and the rise in global temperature. ...
The growing environmental concerns related to fossil-based power usage have led to a global transition towards renewable and conservative energy usage practices. In the context of human thermal comfort within enclosures, Phase Change Materials (PCMs) are deployed as effective passive conditioning media to curtail active air-conditioning demands. The successful functioning of PCM is strongly dependent upon a match between its thermophysical properties and the working environment’s thermal attributes. This creates a multifaceted selection scenario, given the availability of PCMs with a wide range of thermophysical properties. In this study, we investigate the case of selecting suitable PCM for passive thermal management in an automobile cabin. Various decision strategies and analytical methods are implemented to evaluate the efficacy of PCM selection using Multiple Objective Decision-Making (MODM), and Multiple Attribute Decision-Making (MADM) approaches. This study integrates different approaches and provides a comparative analysis of the selection processes. MODM is used for objectively evaluating the attributes (or properties of the PCMs) with Ashby’s approach. The Analytic Hierarchy Process (AHP) and the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) are used along with the entropy-based weights. The selection algorithms suggest the suitability of Gallium and a few other PCMs for the desired application. This study could be a precursor to experimental and computational fluid-based investigations for problems where the test set of PCMs could be narrowed down in the initial stage to save subsequent analysis time and money.
... The adverse effect due to the use of the AC system on vehicle performance for either hybrid or fully electric powertrains is fairly obvious. In fact, it has been found experimentally that conventional HVAC causes up to 16.7% and 50% decrease in driving range for full load cooling and heating, respectively [3]. ...
... 9, 10 Lee's experimental results show that due to the electricity consumption of the PTC electric heater, the driving range of EVs could be reduced up to 50%. 11 However, because EVs are still relatively new, research of heat-pump systems in EVs is still in its early stage, and studies of the performance of heat-pump systems will become increasingly important for airconditioning in EVs. A motor-driven compressor is one of the most promising solutions. ...
Fuel cell vehicles (FCVs) are becoming increasingly popular because they are both environmentally friendly and energy efficient. However, because no waste heat from the internal combustion engine can be used, the additional electricity needed to heat the cabin in cold weather increases the energy consumption substantially. This also lowers both the fuel economics and driving range. The required additional heating is typically done with a positive temperature coefficient (PTC) electric heater. To overcome the associated performance problem, a novel vehicle-integrated thermal management system (VTMS) with a heat-pump system is developed and investigated in this study. Using a simulation, the performance of the VTMS is investigated with respect to cooling performance, heating performance, and heating energy consumption for several different heat sources. For four different driving cycles, the equivalent hydrogen consumption (EHC) is highest when the PTC heater is used. The heat-pump system, which uses waste heat generated by a proton exchange membrane fuel cell, shows the lowest EHC. The results reveal that the use of a heat-pump heating system with waste heat can reduce hydrogen consumption by ∼14.6%, 6.5%, 16.9%, and 16.7% compared to PTC heating. Furthermore, the driving ranges increased by 17.2, 6.8, 20.3, and 12.6 km per 100 km, respectively. The VTMS, thanks to its ability to reduce energy consumption effectively, makes it possible to improve the thermal comfort in the vehicle cabin, which is especially useful for the commercialization of FCVs.
... The test results showed that AC system was the largest energy consumption part of a highly efficient hybrid electric vehicle and had a huge impact on fuel consumption. The experimental data test by both Azadfar et al. and Lee et al. showed that with various driving modes (on different roads with different speeds), operating AC with full power had a significant influence on the total driving range [9,10]. ...
The air conditioning (AC) system of electric vehicles (EVs) consumes a large part of electricity of on-board batteries and influences the continue voyage course seriously. The feasibility of sorption type AC for EVs has been verified theoretically to decrease this part of energy consumption. However, the choice of optimal working pairs based on local working conditions is not considered before, which can realize not only high efficiency but also the steady and reliable operation. Thus in this paper, different solid sorption working pairs used in sorption type AC under different temperature zones are studied. We utilized Rubotherm balance test unit to study the sorption properties of various working pairs (halide-ammonia) and selected candidate working pairs by Clapeyron equation and energy analysis. Results show that MnCl2 is the only choice for cold temperate zone (CTZ) and CaCl2 is optimal for warm temperate zone (WTZ), while the mixed double halide (MnCl2 and CaCl2) is recommended in other zones. In middle temperate zone (MTZ), the probability for performance dropping down is relatively large, thus the ratio (CaCl2:MnCl2) is recommended as 0.33∼1 to take advantage of the stability property of MnCl2. While in Qinghai-Tibet plateau cold area (QTPCA, the special temperature zone in China), the ratio is chosen as 2∼3 because only under the limiting condition reaction \(\left[{{\rm{Ca}}{{\left({{\rm{N}}{{\rm{H}}_3}} \right)}_8}} \right]{\rm{C}}{{\rm{l}}_2} \Leftrightarrow \left[{{\rm{Ca}}{{\left({{\rm{N}}{{\rm{H}}_3}} \right)}_4}} \right]{\rm{C}}{{\rm{l}}_2} + 4{\rm{N}}{{\rm{H}}_3}\) is invalid. Because the continued high environmental temperature will increase the probability of limiting condition, ratio of subtropical zone (STZ) is still selected as 2∼3 while that of tropical Zone (TZ) is 1∼2. Taking WTZ under summer condition as example, by using sorption type AC with CaCl2 as sorbent, the increment voyage course (IVC) over the practical voyage course with conventional compression AC system (PVC) ranges from 9.4% to 37.7% for different type of EVs, i.e. the continue voyage course is increased effectively. This work provides the guidance for choosing optimal working pairs for actual utilization.
... The exclusive available energy for EVs propulsion is the electricity stored in the battery pack, so any additional power consumption implies a reduction of the driving range. Generally, AC systems cause about 30-40% average decrease in driving range depending on the size of AC and the driving cycle for EVs [12,13]. Pino et al. [14] numerically found that an increment of hydrogen consumption is between 3% and 12.1% when the AC system is operated in a FCEV. ...
The air conditioning (AC) system provides cool, heating and ventilation in the cabin of the electric vehicles (EVs). It is necessary to control the interior thermal environments of the vehicle and ensure safety in visibility. Because AC systems are electrically powered, vehicle range is reduced drastically when the AC system is operating. EVs present a particular challenge to the development of more efficient AC systems for automotive applications. In this paper, the state of the art for various AC system solutions to EVs was critically reviewed. The investigations of alternative solutions are continuing along many parallel routes, e.g. vapor compression refrigeration-dedicated heater AC systems, reversible vapor compression heat pump AC systems, non-vapor compression AC systems and integrated thermal management system combined AC and battery pack. The characteristics and particular applications of each solution have been extensively discussed. Finally, a comparison listing the various pros and cons of the different available solutions was presented.
... According to a study of the Swiss laboratory EMPA (Swiss Federal Laboratories for Materials Science and Technologies), during small trips in city, using air conditioning can increase fuel consumption by 30%, and outside agglomeration by more than 15% for conventional vehicle [1]. In electrical vehicle, the use of the air conditioning involves an important reduction of the vehicle autonomy and of the cruising distance by 33% considering average use [2]. In winter, it induces a consumption of the stack battery energy of more than 50% in order to insure good driving conditions [3]. ...
... This results in a driving range reduction, further worsened by energy storage devices limited capacity. Previous studies have modeled the device-level function and energy consumption of HVAC systems as well as the impact on the vehicle driving range [6][7][8][9][10][11]. All these studies revealed a significant impact on driving range; depending on air conditioner size, driving cycle and external weather conditions, the driving range decrease has been estimated in a range between 16% and 36% [6]. ...
Besides providing energy for traction, an electric vehicle battery operates on-board auxiliary systems, among which air conditioning features the highest energy consumption and reduces significantly the driving range. Furthermore, electric vehicles heating needs are typically fulfilled through high-consuming resistors. In this respect, heat pumps promise higher energy efficiency and an increase in all-electric range.
This paper analyses a reversible heat pump HVAC system equipped with a regenerative heat exchanger for pre-conditioning and hygrometric comfort improvement, and assesses air-conditioning energy loads and their impact on driving range for a vehicle performing daily commutes in different Italian cities. The dynamic model was set up in a Modelica framework. The overall system integrates component models calibrated against experimental data.
Results confirm that air conditioning, consuming up to 32% of the energy required for traction on a daily commute, highly impacts on the all-electric range, which can decrease to 72 km from a base value of 94 km. In heating mode, replacing a resistor with a heat pump reduces consumption by 17–52% depending on geographical context, which proves to be highly effective in particularly demanding summer conditions lessening the driving range decrease up to 6%.
... The use of the air-conditioning (AC) in electric cars decreases the driving range by 33% considering an average use (Lee et al., 2013). Compared to conventional cars, all-electric cars face an additional challenge: the waste heat from the powertrain of all-electric vehicles is not enough to provide a comfortable environment in winter. ...
The use of air conditioning in all-electric cars reduces their driving range by 33% in average. With the purpose of reducing the energy consumption of the vehicle and optimising the performance of the batteries, the mobile air-conditioning can be integrated with the temperature control system of the powertrain by means of a coolant loop. In such layouts, the air-to-coolant heat exchangers must operate efficiently in both air heating and cooling modes. Dynamic simulation tools comprising the entire thermal system are essential to assess its performance. In this context, fast but accurate models of the system components are required.
... The automobile industry is striving to replace internal combustion engine vehicles with environmentally friendly electric vehicles (EVs) to address global energy depletion and environmental pollution. The one-charge driving range of EVs must be improved to boost EV use by reducing battery power consumption, which requires the development of a highly efficient EV heating system [1,2]. Apart from powering the vehicle engine, the EV heating system accounts for the majority of energy consumption; therefore, some recent studies have applied high-efficiency heat pumps for heating to improve the driving range of EVs [3][4][5]. ...
A high-voltage positive temperature coefficient (PTC) heater has a simple structure and a swift response. Therefore, for cabin heating in electric vehicles (EVs), such heaters are used either on their own or with a heat pump system. In this study, the sintering process in the manufacturing of PTC elements for an EV heating system was improved to enhance surface uniformity. The electrode production process entailing thin-film sputtering deposition was applied to ensure the high heating performance of PTC elements and reduce the electrode thickness. The allowable voltage and surface heat temperature of the high-voltage PTC elements with thin-film electrodes were 800 V and 172°C, respectively. The electrode layer thickness was uniform at approximately 3.8 μm or less, approximately 69% less electrode materials were required compared to that before process improvement. Furthermore, a heater for the EV heating system was manufactured using the developed high-voltage PTC elements to verify performance and reliability.
... These features make magnetic refrigeration a potentially attractive option for mobile air-conditioning (MAC) systems, whose performance is key to reduce the energy consumption of vehicles. In average weather conditions, the use of the air conditioning (AC) can reduce the fuel economy of mid-sized petrol-driven automobiles by 20% (Farrington and Rugh, 2000) and the driving range of electric vehicles by 33% (Lee et al., 2013). ...
The features of an active magnetic regenerator refrigerator (AMRR) are determined for its application in mobile air-conditioning (MAC) systems. The thermal requirements of an electric vehicle have been firstly obtained and result in a cooling demand of 3.03 kW at a temperature span of 29.3 K. A comprehensive parametric study has been conducted in order to find the AMRR design and working parameters that fulfill the vehicle needs with a minimum electric consumption and device mass. Specifically, a permanent-magnet parallel-plate AMRR made of Gd-like materials is considered. According to the possibilities of current prototypes, in the study the cycle frequencies have been limited to 10 Hz and the applied magnetic fields, to 1.4 T. The results show that an AMRR made of plates between 30 and 40 µm thick and channels between 20 and 40 µm high could meet the vehicle demand with a COP between 2 and 4 and a total mass between 20 and 50 kg. Compared to vapor-compression devices for MAC systems (COP = 2.5 and mass 12 to 15 kg), the AMRR works optimally with fluid flow rates at least 3 times larger. In order to integrate AMRRs into MAC systems, the hydraulic loops should be consequently redesigned.
... This strains the battery and results in rapid depletion of the stored energy. In fact, it is estimated that the use of air conditioning typically results in a 33% decrease in the EV's range [4]. Farrington and Rugh [5] provided a comprehensive insight into the detrimental impact of an auxiliary electrical load on the EV's range performance. ...
Poor cruise performance of Electric Vehicles (EVs) continues to be the primary reason that impends their market penetration. Adding more battery to extend the cruise range is not a viable solution as it increases the structural weight and capital cost of the EV. Simulations identified that a vehicle spends on average 15% of its total time in braking, signifying an immense potential of the utilization of regenerative braking mechanism. Based on the analysis, a 3 kW auxiliary electrical unit coupled with the traction drive during braking events increases the recoverable energy by 8.4%. In addition, the simulation revealed that, on average, the energy drawn from the battery is reduced by 3.2% when traction drive is integrated with the air-conditioning compressor (an auxiliary electrical load). A practical design solution of the integrated unit is also included in the paper. Based on the findings, it is evident that the integration of an auxiliary unit with the traction drive results in enhancing the energy capturing capacity of the regenerative braking mechanism and decreases the power consumed from the battery. Further, the integrated unit boosts other advantages such as reduced material cost, improved reliability, and a compact and lightweight design.
div class="section abstract"> Electric vehicles (EV) have become very significant and potential way to reduce greenhouse gas emissions on a worldwide scale. EV also provides Energy security, as it reduces the dependency on petroleum producing countries of the world. Similar to the conventional Internal Combustion Engine Cars, in Electrical Vehicles also the efficient air conditioning system is very important for providing thermal comfort and for giving safe driving conditions. In Air Conditioning systems for EV, the heating option is available in the form of Electrical heaters and Heat Pump systems. The Heat pumps have become more popular compared to the electrical Positive Temperature Coefficient (PTC) heaters because of their highly efficient and energy saving designs. However, there are still some issues with using heat pumps. One of such issue is their less Coefficient of performance (COP) at low ambient conditions. Experimental results also show that the driving range decreases by using the electric heating system in vehicles.
This paper presents a study on the solutions for increasing the efficiency of heat pump at low ambient conditions. The waste heat coming out from the Traction Motor and power electronics of Electric Vehicles is being utilized for increasing the temperature of Air, which is entering the condenser in Heating mode. This has been done using a heat Exchanger placed in front of the condenser. The study is being evaluated using Coil Designer software for component level simulations and further for the system level simulations, the Kuli software has been used. The study has also resulted in increasing the COP of the system in the Heating Mode.
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Electric vehicle (EV) is more environmental-friendly than gasoline vehicle because the main power is not petrol. For the heating system, the waste heat generated by engines is recycled to heat the cabin of gasoline ones, while the EV need extra electric energy consumption for heating the cabin which decreases the driving range. Personal comfort system (PCS) has been reported that it is an alternative technique to improve occupant thermal comfort and indirectly save building heating energy. This study aims to investigate the occupants’ thermal sensation under four heating modes in the EV cabin in winter, including no heating, only PCS, only air conditioning, and both air conditioning and PCS. The field survey is conducted in a parked EV with 12 subjects. Three thermal comfort indexes (PMV, SET*, and operative temperature Top) are used and assessed for their applicability in the thermal environment of the EV. Results show that the thermal environment in the cabin is non-uniform and dynamic with the air conditioning mode, while the PCS mode just slightly affects the temperature differences inside. Meanwhile, the subjects’ thermal sensations cannot maintain neutral or warmer under the PCS mode only. The results of PMV are lower than the subjects’ actual thermal sensation votes (TSV), while the results of SET* and Top show significant linear relationships with the TSV for the correlation coefficients above 0.80. Compare to the air conditioning mode, the neutral SET* and neutral Top are decreased by 2.7°C and 1.6°C under the mode with PCS and air conditioning, respectively. The findings indicate that PCS not only has a positive effect on improving the cabin environment and occupant's thermal sensation but also has the potential to lower the setting temperature of air conditioner of EVs in winter.
Energy-efficient thermal management of heating, ventilation, and air-conditioning (HVAC) and battery cooling systems is essential for an enhanced driving range of electric vehicles. With recent advances in vehicle connectivity technologies and vehicle computation units, a predictive model has been emphasized in control design. However, the system complexity due to refrigerant circuits and coupling with the battery cooling system makes it challenging to develop a computationally inexpensive model for potential model predictive control applications. This paper presents a novel control-oriented model to capture the behavior of a combined HVAC and battery cooling system for electric vehicles. To reduce the complexity due to the nonlinear two-phase flow heat transfer, the refrigerant circuit is modeled based on the assumption of a quasi-steady ideal vapor-compression cycle. The proposed model is calibrated with a three-step optimization process and then validated against a high-fidelity physics-based model with open-loop simulations. The simulation results show the effectiveness of the proposed model with four states and five actuators: the root mean square errors (RMSE) of the battery temperature and the coolant temperature are 0.41°C and 0.35°C, respectively, and the normalized RMSEs of the heat transfer rate at the heat exchangers are within the range of 2.8% to 10.6%.
With increasingly serious environmental and energy issues, efficient and environmentally friendly electric vehicles have received more attention. However, the high heating and dehumidification energy consumption of their air conditioning system reduces their driving range in winter, giving passengers and drivers range anxiety. In this study, a dual-evaporation temperature heat pump system is proposed to reduce the energy consumption of electric vehicle air conditioning systems in winter, and a simulation model of the proposed system is developed. First, the volume ratio of the dual-cylinder compressor is optimized. Subsequently, the performance of the proposed system in various operation modes under different ambient conditions is compared. The results indicate an optimized volume ratio of 2.85, which is taken as the system’s design condition. The dual-evaporation temperature heating dehumidification mode shows superior performance compared with the conventional mode under typical winter conditions in three different climatic zones. Moreover, energy consumption can be reduced by reasonably controlling the operation mode based on ambient conditions. An operation strategy for the dual-evaporation temperature heat pump system in winter is proposed through the regional division of the psychrometric chart, and the energy-saving operation mode of the system is analyzed for different climate zones in China.
Environmental protection initiatives are speeding up the replacement of the present IC engine-based transportation system with an electric motor-driven system. In electric vehicles (EV), energy stored in batteries is used for the traction of the vehicle and the operation of the auxiliaries. The range of the electric vehicle was identified to be one of the major challenges faced by the EV segment. The optimization of the consumption of stored energy is the best solution for range improvement in an EV. Auxiliaries in the vehicle include basic accessories such as a lighting system and equipment for improved comfort such as air conditioners. Air conditioning equipment is the major power-consuming auxiliary in an EV apart from the traction motor. This review article discusses the significance and influence of different components of the air conditioning system, and methods followed by researchers to optimize the performance and reduce the energy consumption of the air conditioning system to extend the range of vehicles. The effects of thermal load and volume of space to be conditioned were also considered in this study. This review concludes by stating the different possibilities for the reduction in power consumption and emphasizes zonal air conditioning of occupant space as a solution for reducing energy consumption or increasing the range of EVs. Compared to full-space air conditioning, zonal AC can reduce power consumption by up to 51%.
In order to improve the temperature maintenance capacity for the battery of extended range electric vehicle (EREV) in low temperature environment, a microencapsulated phase-change material suspension (MPCMS) based integrated thermal management system (ITMS) is proposed. The working modes of the proposed ITMS are divided based on series-parallel connections of the battery thermal management system (BTMS), motor thermal management system, and auxiliary power unit (APU) thermal management system; the structural parameters of the proposed ITMS are determined by robust design; and the system performance difference between the proposed ITMS and the traditional BTMS is verified through the comparative simulation in −20°C environment. The results show that the proposed ITMS can significantly delay the decline of battery temperature in the charge-depleting (CD) stage, and can reduce the time of the positive temperature coefficient (PTC) heater being on by 27.26%, and the total being on time by 54.82%. During the charge-sustaining (CS) stage, when the PTC heater is off, the average battery temperature will increase by 15.33°C compared with the traditional BTMS. Based on the proposed ITMS, the temperature maintenance capability for battery can be significantly improved, and the energy consumption of PTC heater and vehicle can be reduced by 48.12%~100% and 13.44%~33.58% respectively.
Thermal discomfort, fuel wastage, health risks, and the death threat of passengers/infants due to the hot soak of car cabin is a hot spot topic all the time. Therefore, the transient analysis method is used to study the distribution of the heat soak temperature in the passenger compartment under different orientation. Besides the research analyzed the effects of four ventilation cases on the driver and rear infant. The results show that both of the driver and infant are subjected to the lowest heat load while the vehicle parked outdoors is facing east at 14:00 and the air temperature around the driver is about 52 °C. The roof ventilation is a effective energy conservation ventilation way for both of driver and infant, as there is the most heat removal efficiency(0.471) and the best cooling effect. The head temperature of driver and infant in roof ventilation is at least 7 °C and 3 °C lower than the other three cases. In addition, the seats ventilation is a better heating way for driver than other ventilation cases, because the air temperature is more even and can be heated to 26.5–29.2 °C for the driver.
Battery electric vehicle has become an important development direction of new energy vehicles because of its advantages of high efficiency, clean and low energy consumption. Thermal management system is required to ensure that the temperature of the battery and motor is in an efficient operating temperature range. However, as the energy required for cooling and heating of the thermal management system is provided by the power battery, the range of electric vehicles is severely reduced. In order to reduce the energy consumption of thermal management system, electric vehicle integrated thermal management system has become an important research direction. In this paper, an integrated thermal management system is designed for battery electric vehicle. The cooling and heating of battery, cooling of motor, and waste heat utilization are considered comprehensively. The simulation model of integrated thermal management system is established, and the accuracy of the model is verified by experiments. The cooling performance, heating performance and waste heat utilization performance of integrated thermal management system were analyzed under different boundary conditions.
It is widely accepted that electrical vehicles (EVs) for goods and people have a crucial role to play in energy transition towards carbon neutrality. Despite significant progress in recent decades, challenges remain in charging times of EV batteries and range anxiety of drivers, compared with vehicles powered by liquid fuels which are several times more energy dense than Li-ion batteries. This perspective article examines two solutions that have the potential to address the challenges: the conversion of diverse forms of wasted energy into electricity (e.g. vibration) and the reduction of battery power for the provision of ancillary services (e.g. cabin thermal comfort).
The regulations regarding emission and air conditioning in the automobile sector have become more stringent worldwide. Air conditioning (AC) is an integral component of an automobile to provide human comfort. For many years, the AC systems in automobiles widely used the vapour compression refrigeration (VCR) method. However, operating automobile AC using a VCR system has high energy consumption and negative environmental impacts. Thus, increasing fuel consumption of conventional vehicles and reducing the driving range of Electric Vehicles (EVs). The significant challenge currently faced is fighting these environmental regulations, reducing fuel consumption of traditional vehicles, and increasing the cruising range of EVs. Although a substantial amount of research was conducted during the last three-four decades, the automobile sector is yet to explore sustainable AC systems. A detailed investigation of various automobile AC systems, categorizing them into active, passive and hybrid AC systems and their interrelation with the vehicle's performance, is presented in this review article. We reviewed, compared, and provided a comprehensive description, and the main resulting enhancements of each AC system category are presented. In addition, applications of hybrid AC systems are discussed with indicating main improvements in energy and fuel consumption. Besides developing these energy-efficient AC systems, the most critical challenge encountered is linked to the automobile standards and regulations that are the main obstacle in taking these new research ideas to commercialization. Within the information and knowledge promulgated in this review article, the evolution and glance of the future insight on alternative environmentally friendly and energy-efficient automobile AC systems after the VCR system can be expedited.
Vehicular configuration optimization thus to prolong driving mileage has become an essential issue in affecting the future prospect of electric vehicles. This study proposed to simulate energy consumption of electric vehicles using real-world driving cycle (RWDC) data in urban area. First, operational data of electric commercial vehicles were obtained for RWDC development. Vehicle configuration parameters, including vehicle body, battery, tire, transmission, were chosen for the simulation in ADvanced VehIcle SimulatOR (ADVISOR) software package, by which the estimated benefits and costs by optimizing each parameter were approximated to provide a benchmark for choosing the controlled variable during the optimization. Vehicle mass, rolling resistance coefficient and accessory power were selected as the controlled variables for the cost-benefit analysis with the vehicle life cycle driving mileage as the benchmark, reducing the short-term profit limitation of the optimization evaluation. The proposed method would have practical guidance significance in formulating energy optimization schemes for electrical commercial vehicles.
A cabin climate control system, often referred to as a heating, ventilation, and air conditioning (HVAC) system, is one of the largest auxiliary loads of an electric vehicle (EV), and the real‐time optimal control of HVAC brings a significant energy‐saving potential. In this article, a linear‐time‐varying (LTV) model predictive control (MPC)‐based approach is presented for energy‐efficient cabin climate control of EVs. A modification is made to the cost function in the considered MPC problem to simplify the Hessian matrix in utilizing quadratic programming for real‐time computation. A rigorous parametric study is conducted to determine optimal weighting factors that work robustly under various operating conditions. Then, the performance of the proposed LTV‐MPC controller is compared against a rule‐based (RB) controller and a nonlinear economic MPC (NEMPC) benchmark. Compared with the RB controller benchmark, the LTV‐MPC reaches the target cabin temperature at least 69 s faster with 3.2% to 15% less HVAC system energy consumption, and the averaged cabin temperature difference is 0.7°C at most. Compared with the NEMPC, the LTV‐MPC controller can achieve comparable performance in temperature regulation and energy consumption with fast computation time: the maximum differences in temperature and energy consumption are 0.4°C and 2.6%, respectively, and the computational time is reduced 72.4% on average with the LTV‐MPC.
Modern day electric vehicles (EVs) use conventional heating, ventilation, and air-conditioning (HVAC) systems from engine-based vehicles. This brings forward new challenges in the name of range anxiety and thermal comfort of passengers that need to be achieved through a single charge of the battery unlike through high energy density fossil fuels. The present work deals with developing a high-fidelity physics-based model of HVAC components from core fundamentals that use location and time parameters to compute heat load so that performance can be analyzed in various climates. It is validated with real data from tests on a practical HVAC system of a running transit electric bus. Using this model as base, a cooling methodology based on direct evaporative cooling (DEC) is introduced, and the benefits of such a technique are illustrated by the comparison between the conventional and newly proposed system. It is observed that the DEC-assisted vehicle HVAC system achieves significantly greater cooling than the conventional system, using lesser energy (via compressor run by an electric motor) than before. The effect on tractive power consumption, total energy drawn from the battery, and thermal comfort of passengers has been studied to see where the new system stands as a general proposal. The model-based analysis performed in this article gives insight into the real-time behavior of conventional and DEC-assisted HVAC and builds the foundation for developing hybrid HVAC techniques like DEC-assisted HVAC for improving energy efficiency of the HVAC system.
A simplified state-of-the-art dashboard ventilation system was compared to novel ventilation concepts regarding the cooling dynamics in a full-scale generic car cabin (GCC). The concepts are based on the principle of displacement ventilation with air inlets at floor and ceiling level, well known from studies in aircraft cabins. In the present study, three vertical ventilation concepts were investigated experimentally in the GCC. With the aim to study different climate conditions, a jacket heating system was used to simulate summer conditions. Four thermal manikins were placed in the GCC to simulate the heat release and the obstruction of passengers as well as to measure the thermal comfort. To determine the relevant heat fluxes, a plethora of temperature sensors was installed at significant positions in the GCC. Furthermore, the surface temperatures were measured by means of an infrared camera. The study reveals significant differences in terms of cooling efficiency and thermal comfort for the different ventilation concepts.
KeywordsVertical ventilation conceptsEquivalent temperatureFuture cars
In this work, a simplified mathematical model, concerned with transient heat conduction as well as convective and radiative heat transfer, was developed to predict the variations of temperature and supercooling of the windshield during practical nocturnal cooling processes of a car. Final supercooling (DTfsuper) was introduced as an indicator to evaluate the probability of occurrence of frosting. Following that, the Taguchi statistical method was used to conduct a parameter sensitivity analysis and then figure out the potential control strategies for frosting suppression. The results showed that relative humidity had the most significant influence on the distribution of supercooling during the nocturnal cooling period, whereas the initial temperature as well as the thickness and thermal conductivity of the windshield played a minor role in it. An increase in relative humidity resulted in a significant increase in DTfsuper, which might be expected to trigger an earlier initiation of frosting. The emissivity of the windshield, concerned with the nocturnal radiation potential, showed a considerable effect on the response of DTfsuper, whereas the influence of the total opaque cloud amount appeared to be largely limited. In addition, through a potential control of the thermal conductivity of the windshield, DTf super just exhibited a very limited decline, thus contributing little to frosting mitigation. However, with a moderate potential control of the internal convective heat transfer coefficient, the frosting behavior might be effectively suppressed under a severe condition that favored the occurrence of icing. Besides, by introducing a combined control of the emissivity of the windshield and the internal convective heat transfer coefficient, DTf super could be well reduced to a value below zero even as the relative humidity increased up to 90%, which was supposed to prevent the occurrence of frosting under a far severer condition.
In this study, a novel integrated thermal management (ITM) system combining vapor injection (VI) with battery heat dissipation was proposed. The model of this novel system was developed and validated. On this basis, the effects of injection pressure, battery heat dissipation, and ambient temperature on the heating performance of the novel system were analyzed. Results showed that a maximum COP based on injection pressure existed for the novel ITM system. Compared with the basic vapor injection system, heating capacity and COP of the ITM system with 1 kW waste heat corresponding to the optimum injection pressure were increased by 13.57% and 7.88% at the ambient temperature of −20 °C, respectively. With the increase in battery heat dissipation from 1 kW to 3 kW, heating capacity and COP were improved by 25.81% and 10.80% at the ambient temperature of −20 °C, respectively. The heating performance improvement of the novel ITM system over the basic VI system gradually diminished with increasing ambient temperature.
In the present study, we theoretically and experimentally investigated a typical and practical heterogeneous ice nucleation process on auto windshield under nocturnal radiative cooling and subfreezing conditions. During the experiment, a general class A passenger car was placed outdoors in a subfreezing environment (i.e.,\ 44.14° N, 126.45° E) during nights in January, with a purpose to produce a nocturnal radiative cooling condition for supercooling the windshield to trigger the ice nucleation. The results revealed a distinctive three-stage frosting process: (I) inhomogeneous occurrence of incipient ice nucleation; (II) small-sized ice crystals grew into large-sized ones primarily based on the incipient nucleation sites, together with a continual formation of new nucleation sites and a merging between large-sized and small-sized crystals; (III) large-sized ice crystals coalesced into large-scale groups, tending to make a full ice coverage. Unlike the classical three-period frosting process, the present study exhibited an absence of the drop-wise condensation but with a presence of dendritic crystals nearly parallel to the supercooled surface. Besides, the incipient ice nucleation was first initiated on the upper part of the windshield, which then propagated downward with a further heat loss of the windshield due to the continual nocturnal radiation. Meanwhile, the probable presence of surface roughness or contamination was much more likely to trigger an earlier initiation of incipient heterogeneous ice nucleation. Additionally, the arrival of saturation point, rather than the nominal supersaturation state (i.e., the condensation nucleation point), could be expected to approximately mark the initiation of icing under a practical engineering condition. Higher relative humidity tended to induce an earlier occurrence of ice nucleation and produce a larger surface coverage.
The objective of this study is numerically to investigate the heat transfer characteristics of the integrated heating system considering the temperature of cabin and battery of an electric vehicle under the cold weather conditions. The integrated heating system consists of a burner to combust fuel, an integrated heat exchanger for CHE (coolant heat exchanger) and AHE (air heat exchanger). The heat transfer characteristics like the overall heat exchanger effectiveness, the heat transfer rate, the temperature distribution and the fluid flow characteristics like the pressure drop, velocity distribution of the investigated integrated heating system were considered and analyzed by varying the inlet mass flow rates and the inlet temperatures of the cold air and water, respectively. The average Nusselt numbers for the cold air side and the water side were increased 28.4% and 9.5%, respectively, with the increase of the cold air side Reynolds numbers from 15,677 to 72,664 and the water side Reynolds numbers from 4330 to 11,912. The numerical results showed good agreement within ±9.0% of the existed data and thus confirmed that the present model was valid. In addition, the proposed integrated heating system could be used as the thermal management of the cabin and the battery system of the electric vehicle under the cold weather conditions.
Climate control system in electrified vehicle is quite different from traditional internal combustion engine vehicle, as it cannot use the wasted coolant heat from engine to keep warm of the cabin. For the dehumidifying and reheating air in the electrified vehicle cabin, the use of a dual-evaporator heat pump system could improve the total energy utilization efficiency of the climate control system. In this study, an experimental dual-evaporator heat pump system was set up to investigate dehumidifying and reheating efficiency of a cabin in electrified vehicle. Two dehumidifying modes were chosen in this experiment. One was single-evaporator mode with indoor evaporator only, and the other was dual-evaporator mode with both indoor and outdoor evaporators. The dual-evaporator dehumidifying mode shows higher heat capacity, coefficient of performance, and outlet air temperature, while it has quite lower moisture extraction rate and specific moisture extraction rate compared to the single-evaporator dehumidifying mode. Therefore, a hybrid dehumidifying and reheating method was suggested as a possible option for realization of energy conservation without sacrifice of thermal comfort for passengers.
Electric vehicle mileage is limited because of its dependence on the battery, and moreover is reduced due to the use of battery power for heating in winter and air conditioning in summer. In particular, the capacity of lithium ion batteries decreases as the temperature of the battery falls. At a temperature of -25°C, the capacity is decreased to 60% of that at 25 °C. In particular, PTC heaters, which are mainly used in electric vehicles, increase battery power consumption. Also, the heat pump, and in particular its compressor, consumes a lot of battery power, and it shows poor performance in cold weather. Hence, the PTC heater and heat pump are not good solutions for the heating issues of electric vehicles. According to recent studies, the cruising range of electric vehicles is reduced to about 40% due to the power consumption of the heater at 0 °C. In order to enhance heating performance and initial battery performance of electric vehicles in cold weather, a feasibility study of a fire-operating heating system using a low carbon fuel was conducted in this work, and satisfactory results were obtained.
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