Numerical and experimental investigation on the air flow characteristics of heating, ventilation, and air-conditioning module for a small electric vehicle

2019 ◽  
Vol 234 (6) ◽  
pp. 1597-1609
Author(s):  
Kang Li ◽  
Hao Gao ◽  
Peng Jia ◽  
Lin Su ◽  
Yidong Fang ◽  
...  
Keyword(s):  
Heat Pump ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Flow Characteristics ◽  
Cold Climate ◽  
Airflow Rate ◽  
Positive Temperature ◽  
Air Flow Rate ◽  
Pump System

In electrical vehicles, replacing positive temperature coefficient heater as heat source with an air source heat pump could improve the driving range and decrease energy consumption in cold climate. Design of the heating, ventilation, and air-conditioning module for heat pump system has a significant influence on its performance in each working mode. A newly designed heat pump heating, ventilation, and air-conditioning module was introduced in this paper. The air flow characteristics of the heat pump heating, ventilation, and air-conditioning module in four working modes were analyzed, and the air flow rate and wind resistance were obtained by numerical simulation. Experiments were also conducted for validating its airflow rate in each working mode. Results of these experiments show that some unfavorable phenomena such as flow maldistribution and vortex inside the heat pump heating, ventilation, and air-conditioning module exist, which could lead to insufficient utilization of the heat exchange area of heat exchangers and the generation of aerodynamic noise. Furthermore, the air flow rate of the original heating, ventilation, and air-conditioning module was also measured for comparison, and the designed heat pump heating, ventilation, and air-conditioning module shows nearly 15–20% decrease in each working mode.

Experimental Investigation on Heating Performance of Newly Designed Air Source Heat Pump System for Electric Vehicles

2020 ◽  
Vol 13 (2) ◽  
Author(s):  
Kang Li ◽  
Jun Yu ◽  
Rong Yu ◽  
Lin Su ◽  
Yidong Fang ◽  
...  
Keyword(s):  
Heat Pump ◽  
Electric Vehicles ◽  
Flow Characteristics ◽  
Cold Climate ◽  
Positive Temperature ◽  
Pump System ◽  
Cooling Performance ◽  
Heat Pump System ◽  
Heating Performance ◽  
Driving Range

Abstract Utilizing the heat from air source with heat pump system in electric vehicles shows a significant advantage from thermoelectric heat source for heat supply in cold climate. It could improve the driving range of electric vehicles considerably in winter and replace the positive temperature coefficient (PTC) heater with an acceptable cost and reliability. In this work, a newly designed heat pump system was first introduced with less components and cost. Second, experiments were conducted to investigate its cooling performance, and subsequent heating performance from −10 to 10 °C. The typical heat transfer and flow characteristics of refrigerant were recorded, and the behavior of each component including compressor, evaporator, condenser, and outside heat exchanger were analyzed and interpreted. The results showed that the heating and cooling performance of the new heat pump system could almost remain the same with traditional air-conditioning system in automobile and surely satisfy with the heat requirement of electric vehicles. In the heating mode, the maximum heating capacity increases by 13% at 400 m3/h air volume from 300 m3/h at the ambient temperature −10 °C, while the outlet air temperature decreases by 4–6%. In addition, using a heat pump system showed an increase in the driving range of electric vehicles by 25–31% as compared to PTC heaters.

scholarly journals A twin-fluid injector for FCC feed injection

2019 ◽  
Vol 4 (3) ◽  
pp. 109-115
Author(s):  
Deepak Kumar ◽  
Tushar Sikroria ◽  
Kushari A ◽  
Pramod Kumar ◽  
Sriganesh G
Keyword(s):  
Droplet Size ◽  
Flow Rate ◽  
Liquid Flow ◽  
Liquid Flow Rate ◽  
Air Flow ◽  
Product Yield ◽  
Droplet Velocity ◽  
Injection System ◽  
Airflow Rate ◽  
Air Flow Rate

In Fluidized Bed Catalytic Cracking (FCC) process, hydrocarbon feed undergoes vapour phase cracking in presence of hot regenerated catalyst to produce valuable products like LPG, Gasoline and Diesel. FCC feed injection system is most critical hardware component of FCC unit in order to get desired product yield by minimizing the undesirable dry gas and coke yield. Typically, twin-fluid nozzles (hydrocarbon and stream) are used to atomize the feed. In the present study, a twin-fluid injector, with an internal impactor to minimize the droplet size and velocity, is designed, developed and characterized. The performance of the feeding injector was evaluated using water and air as operating fluids and the droplet size and velocity were measured 150 mm downstream of the injector tip using a PDPA system for different water and air flow rates. The average droplet size (D32) showed an increase while the droplet velocity remained almost constant with the increase in the liquid flow rate for a given flow rate of air, consistent with the increase in droplet size with decreasing air-liquid ratio for twin–fluid atomizers. But, for a given liquid flow rate, the droplet SMD decreased and the droplet velocity increased with increasing airflow rate, which can be attributed to the increase in overall kinetic energy due to the increase in air flow rate. The flow rate of liquid was seen to be independent of air flow rate unlike conventional twin-fluid atomizers. The droplet size was found to be a function of ALR and the local volume flux of the droplets was found to be a function of the liquid flow rate.

scholarly journals Coupling Effect of Air Flow Rate and Operating Conditions on the Performance of Electric Vehicle R744 Air Conditioning System

2021 ◽  
Vol 11 (11) ◽  
pp. 4855
Author(s):  
Anci Wang ◽  
Jianmin Fang ◽  
Xiang Yin ◽  
Yulong Song ◽  
Feng Cao ◽  
...  
Keyword(s):  
Electric Vehicle ◽  
Flow Rate ◽  
Air Conditioning ◽  
Volume Flow Rate ◽  
Air Flow ◽  
Volume Flow ◽  
Air Flow Rate ◽  
Air Volume ◽  
Discharge Pressure ◽  
Air Conditioning Systems

The air flow rate on the gas cooler side is one of the key parameters affecting the performance and running safety of transcritical CO2 electric vehicle air conditioning systems. After experimentally analyzing the effects of the air volume flow rate in the gas cooler on the cycle parameters and system performance, a novel method to evaluate the optimal air flow rate was proposed. In addition, the effect of the gas cooler air volume flow rate on the key performance parameters of the system (e.g., optimal discharge pressure) was explored. Finally, the coupling effects of the compressor speed, ambient temperature and optimal air flow rate on the system performance was also exhaustively assessed. It was found that as the discharge temperature, the CO2 temperature at the gas cooler outlet and the discharge pressure did not vary more than ±2%, the corresponding gas cooler air volume flow rate was optimal. For the single-row and dual-process microchannel evaporator used in this work, the recommended value of the optimal gas cooler air volume flow rate was 2500 m3·h−1. The results could provide reference for the fan speed design of electric vehicle CO2 air conditioning systems, especially for the performance under idling model.

Experimental Study of Solar Air Heating System Based on Unglazed Transpired Collector

2011 ◽  
Author(s):  
Lixin Gao ◽  
Hua Bai ◽  
Xiumu Fang
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Flow Rate ◽  
Temperature Rise ◽  
Air Flow ◽  
Heating System ◽  
Airflow Rate ◽  
Air Flow Rate ◽  
Air Heating ◽  
Collector Efficiency

An experimental rig was set up to test the thermal performance of a solar air heating system based on an unglazed transpired collector of 2.5 m2. The experiment was carried out at Harbin Institute of Technology in the city of Harbin, which is located in northeastern China, at latitude 45°41′ N and longitude 126°37′ E. The tests were spread over a number of days, in which the 4-day experimental data within the period were selected as the sample for analysis. Experimental results show that solar collector’s surface temperature and exit air temperature increase with increasing solar irradiation. The influence of ambient temperature on surface temperature and exit temperature is negligible. Temperature rise decreases with increasing air flow rate, while collector efficiency increases with increasing air flow rate. For an air flow rate of 100 m3/h in Test 1, the average air temperature rise and collector efficiency were 28.86°C and 72% respectively; for an air flow rate of 235 m3/h in Test 2, the average air temperature rise and collector efficiency were 11.52°C and 78% respectively. Higher airflow rate tends to operate the collector at lower surface temperature, which results in lower overall heat losses from the collector to the surroundings, therefore increasing airflow rate reduces air temperature rise and enhances the collector efficiency. The average efficiency of the experimental solar air heating system in the 4-day experiment period was 72%, 78%, 61%, and 72% respectively, which are higher than most conventional glazed flat-plate solar air collectors. With better coordination with architectural design at early stage in a project, this building-integrated solar air heating system can be both aesthetically and technically viable.

scholarly journals Minimization of fan energy consumption in ventilation and (or) air-conditioning systems as an optimization calculus of variations

2019 ◽  
Vol 116 ◽  
pp. 00033
Author(s):  
Michał Karpuk
Keyword(s):  
Energy Consumption ◽  
Calculus Of Variations ◽  
Flow Rate ◽  
Air Conditioning ◽  
Air Flow ◽  
Rate Function ◽  
Hazardous Substances ◽  
Air Flow Rate ◽  
Starting Conditions ◽  
Air Conditioning Systems

The article presents an optimization calculus of variations of fan energy consumption in ventilation and (or) air-conditioning systems. It defines an air flow rate function that depends on the time of operation in the defined room size, starting conditions and the function of hazardous substances emission rate in the room. The differential form of air flow rate dependence on density of hazardous substances allows to establish a connection between air pollution in the room and a fan air flow rate, i.e. fan energy consumption. Creating a fan energy model experiment in the room in different conditions allows to minimize energy consumption to 5–30% depending on existing conditions.

scholarly journals A Study of Optimal Refrigerant Charge Amount Determination for Air-Conditioning Heat Pump System in Electric Vehicles

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 657 ◽  
Author(s):  
Kang Li ◽  
Jun Yu ◽  
Mingkang Liu ◽  
Dan Xu ◽  
Lin Su ◽  
...  
Keyword(s):  
Heat Pump ◽  
Electric Vehicles ◽  
Air Conditioning ◽  
Cold Climate ◽  
Operating Conditions ◽  
Pump System ◽  
Heat Pump System ◽  
Heating Performance ◽  
Correlation Models ◽  
Battery Energy

With regard to concerns about an electric vehicle’s driving range extension in a cold climate, an air-conditioning heat pump (ACHP) shows considerable advantage over thermoelectric heaters for battery energy conservation. The effect of refrigerant charge amount for cooling and heating performance of the ACHP system is significant. The optimal charge, realizing the optimal system performance, is usually determined by experiments of cooling and heating performance. In this paper, the optimal charge determination process based on a newly designed ACHP applied in electric vehicles was introduced. Relationships of characteristics with charge in two modes were investigated by experimental and theoretical methods. Firstly, the performance of the ACHP system was respectively investigated at different charge amounts in cooling and heating operating conditions according to key parameters of system cycles. Secondly, the intersection platforms of subcooling and superheat variation curves with refrigerant charge amount were obtained for determining optimal charge amount of the system further by comprehensive analysis. Finally, the theoretical calculation of charge with three instructive and classical void friction correlation models were applied for better comparisons. It was found that charge amount calculated by the Hughmark model proved to be most consistent with the comprehensive experimental results.

Flow Characteristics of Electronic Expansion Valves for Heat Pump System Using Carbon Dioxide as a Refrigerant

2010 ◽  
Author(s):  
Ook Joong Kim ◽  
Young-Ho Choi ◽  
Seok Ho Yoon
Keyword(s):  
Carbon Dioxide ◽  
Mass Flow Rate ◽  
Heat Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Inlet Temperature ◽  
Pump System ◽  
Heat Pump System ◽  
Temperature And Pressure

An experimental study on the flow characteristics of electronic expansion valves (EEVs) for heat pump system using carbon dioxide as a refrigerant have been carried out in this study. Many researches and efforts have been made to replace chemical refrigerants like Chloro-Fluoro-Carbon (CFC) and Hydro-Chloro-Fluoro-Carbon (HCFC) with natural refrigerants such as carbon dioxide and apply natural refrigerants to chillers or heat pump systems. In this study, we focused on the development of EEV and 4-way valve among the important components of heat pump system using natural refrigerant. The mass flow rate was measured at various EEV inlet temperature and pressure conditions with respect to several EEV openings operated at a heat pump system which has about 10 kW of cooling capacity. The heat pump system consists of a reciprocating compressor, a gas cooler, an evaporator, an EEV, and a 4-way valve which was developed for this study. The inlet temperature and pressure of an EEV was varied from 5°C to 40°C and from 7 MPa to 10 MPa, respectively. The mass flow rate of carbon dioxide through the EEV ranged from 50 g/s to 120 g/s. The mass flow rate of carbon dioxide around the critical point was affected by the inlet temperature and pressure of EEV, valve opening, and density variation. An empirical mass flow rate correlation of carbon dioxide based on the Buckingham π-theorem was developed in this study, and this correlation predicted experimental data within an average absolute deviation of 4.2%. The correlation can be applied to predict the mass flow rate through EEV used in the heat pump system using carbon dioxide as a refrigerant. And the reliability test of developed 4-way valve was conducted. This 4-way valve showed stable operation in the high pressure condition.

Numerical Modeling of Perforated Tile Flow Distribution in a Raised-Floor Data Center

2007 ◽  
Author(s):  
Emad Samadiani ◽  
Jeffrey Rambo ◽  
Yogendra Joshi
Keyword(s):  
Numerical Modeling ◽  
Flow Rate ◽  
Data Center ◽  
Air Conditioning ◽  
Air Flow ◽  
Flow Distribution ◽  
Air Flow Rate ◽  
Tile Flow ◽  
Operating Points

This paper is centered on quantifying the effect of computer room and computer room air conditioning (CRAC) unit modeling on the perforated tile flow distribution in a representative raised-floor data center. Also, this study quantifies the effect of plenum pipes and perforated tile porosity on the operating points of the CRAC blowers, total CRAC air flow rate, and its distribution. It is concluded that modeling the computer room, CRAC units, and/or the plenum pipes could change the tile flow distribution by up to 60% for the facility with 25% open perforated tiles and up to 135% for the facility with 56% open perforated tiles.

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