Supply Air Temperature Research Articles

Thermal and draught perception in fluctuating stratified thermal environments with intermittent impinging jet ventilation

This study proposes a new integrated air supply strategy of impinging jet ventilation (IJV) and intermittent airflow to improve indoor thermal comfort. Vertical thermal stratification is created by the IJV, and a fluctuating thermal environment is created by the intermittent airflow. Three pulsating periods (3 min, 5 min, and 7 min), two supply air temperatures (18 °C and 16 °C), and four air supply velocities (1.8 m/s steady, 1.5/2.1 m/s, 0.9/2.7 m/s, and 0/3.6 m/s) were designed. In both steady and fluctuating indoor environments, fifteen college students were asked to report their perceptions of thermal sensation, thermal comfort, thermal preference, ankle air movement acceptability and preference, and perceived air quality. The results showed that pulsating airflow could lower the mean air temperature above 0.6 m and raise it below 0.6 m. Furthermore, pulsating airflow could reduce overall and local thermal sensation by up to 0.21 and 0.28 scale unit, respectively, and the thermal sensation difference between the head and the foot by up to 0.23 scale unit. While in neutral thermal conditions, the pulsating period of 3 min had the best cooling effect of the 10 cases, but the corresponding percentage of mean dissatisfied ankle draught was 4.3% higher than in the steady operation case. Draught sensation is so closely related to ankle thermal sensation that extending the pulsating periods to 5 or 7 min could reduce ankle draught risk by up to 12.3%. The perceived air quality did not differ significantly between the steady and intermittent cases. The intermittent operation of IJV was shown to have superior cooling performance in order to improve indoor thermal comfort.

Effects of operation parameters on the ventilation performance for a floor-standing air conditioner

Floor-standing air conditioners (FSAC) have been widely used in civil and office buildings due to the advantages of high cooling/heating capacity and easy installation. The major challenge of FSAC is to lower energy consumption while meeting the requirements of thermal comfort (TC) and indoor air quality (IAQ). Using the validated computational fluid dynamics (CFD) method, this study extensively examines the effects of some key operation parameters on the FSAC performance. The operation parameters include controllable supply vane angle, supply air velocity, supply air temperature, and uncontrollable outdoor weather condition. The main ventilation performance is assessed by indices such as predicted mean vote (PMV), predicted percent dissatisfied (PPD), draught rate (DR), local mean age of air (LMAA), and energy consumption (Psystem). The relative importance of the operation parameters for each ventilation performance index is identified by evaluating the individual effects of the operation parameters on such performance. Comparison of the individual and combined effects of the operation parameters on the ventilation performance reveals that the corresponding most important operation parameters account for 90.6%, 97.4%, 77.1%, 95.1%, and 79.2% of the variations in PMV, PPD, DR, LMAA and Psystem caused by the combined effects, respectively. Additionally, the outdoor weather conditions do not significantly affect DR, PPD and LMAA, but can shift PMV to uncomfortable levels. Finally, the constant-air-volume (CAV) system is recommended for FSAC during the steady stage and a simplified operation strategy is proposed.

Visualized study of wetting enhancement and thermal performance of fiber-coated indirect evaporative cooler

Poor wetting is a serious problem facing the traditional aluminum and polymer indirect evaporative cooler, which largely deteriorates its cooling performance. Therefore, a fiber coating (70% rayon + 30% polyester textile) is proposed to be attached to the plate heat exchanger walls to improve the wetting condition by its good moisture diffusion. Firstly, the characteristics of the fiber are evaluated by a laser microscope, wicking height and diffusivity tests. Then, its application on an indirect evaporative cooler is investigated. On one hand, to quantitatively evaluate the wetting enhancement by the fiber, comparative visualized experiments are carried out between fiber-coated and non-coated cooler to investigate the water distribution, wetting ratio and water retention at three typical core positions under different spraying time (5 s–180 s), water flow rate (2 L/min–6 L/min) and nozzle height (50 mm to 250 mm). The visualized experiment innovatively combines fluorescence display and digital image processing methods. On the other hand, the thermal conductivity of the fiber-coated plate is tested and used as input for the heat and mass transfer model of indirect evaporative cooler to predict the outlet air temperature. The results show that the non-coated plate suffers from uneven water distribution and low wetting ratio, but the fiber coating can significantly improve the wetting conditions by providing 100% wetting ratio in only 30 s under 150 mm nozzle height and 5 L/min flow rate. The influence of thermal resistance of wetted fiber on outlet air temperature is negligible, but the dry fiber will increase the supply air temperature by 0.3 °C.

Numerical analysis for the optimization of multi-parameters stratum ventilation and the effect on radon dispersion

To reduce hazards due to the radon dispersion on occupants, careful consideration of multi-parameters of stratum ventilation is necessary, including air supply velocity, temperature, angle and air outlet position. In this study, the radon dispersion in a typical office with stratum ventilation was evaluated based on experimental measurements and computational fluid dynamics (CFD) modelling. Besides, the ventilation performance of each scheme was evaluated by using a technique of order preference by similarity to the ideal solution (TOPSIS) method. Results showed that the mentioned factors and their interactions could pose important impacts on the indoor environment. Combining with TOPSIS, the optimal operation of the stratum ventilation was determined. Compared with the worst ventilation scheme, the ventilation effectiveness was increased by 77.4%, the air distribution performance index (ADPI) was increased by 38.1% and the radon radiological effective dose rate was reduced by 63.4%. The findings may form an important mitigation control strategy to effectively minimize radioactive exposure in indoor environments. • Operation of stratum ventilation for cooling and reducing radon in a typical office is optimized. • Parameter impact on stratum ventilation performance for cooling is analyzed. • Compared with the worst ventilation scheme, the maximum ventilation effectiveness was increased by 77.4%, the air distribution performance index (ADPI) was increased by 38.1% and the annual effective dose of radon exposure was reduced by 63.4%.

Investigation into effect of non-uniform thermal environment on thermal sensation under stratum ventilation for heating by using interpolation-based multi-level fuzzy comprehensive evaluation

Stratum ventilation for heating is applied to provide satisfactory indoor thermal environments with great potentials in winter. Indoor non-uniform environments are important for both overall and local thermal sensations in the same occupied subzone (i.e., vertical spaces) as well as different subzones of the occupied zone (i.e., horizontal spaces) under the effect of supply air jets. This study carried out field chamber experiments to consider the effect of non-uniform environments on both overall and local thermal sensations under stratum ventilation for heating using the multi-level fuzzy comprehensive evaluation (MFCE) method. This method has a multi-level structure to simultaneously investigate thermal sensation in both vertical spaces and horizontal spaces. The interpolation models of thermal sensation are helpful to enlarge the experimental sample size investigated by MFCE. The results showed that the interpolation-based MFCE method can quantitatively analyze the effect of non-uniform environments on thermal sensation in different subzones of the occupied zone from vertical spaces and horizontal spaces under the effect of supply air parameters. Compared with supply air temperature, supply air velocity has the opposite influence on the variation range of both integrated thermal sensations of feet, head and overall body and local thermal sensation of feet between the occupied subzones 1 and 2. Supply air temperature and velocity of 25–27 °C and no less than 1.1 m/s were recommended to improve the non-uniformity of thermal environments.

Improvement for energy efficiency and control characteristics in variable air volume system using in-situ sensor calibration method based on autoencoder

The accuracy of sensor measurement has an important influence on energy efficiency and control characteristics of air conditioning systems. However, the sensor will inevitably have errors due to sensor installation location or aging in the practical system. In previous studies, the sensor virtual in-situ calibration (VIC) method is proposed to diagnose and calibrate sensor faults based on physics-based methods with plenty of sensors. However, the basic sensors are only installed due to the cost and limited installation space in the practical system, which restrains this method. To address this problem, the autoencoder (AE) based on the internal relationship between sensor variables is applied to establish the sensor model to achieve calibration. This paper studies the applicability of the AE that constructs sensor models with limited sensors, and the accuracy of the VIC method under different working conditions. The results show that the AE can well realize the sensor model construction with high accuracy, which lays a foundation for the implementation of the VIC method. Meantime, the accuracy for different scenarios of the single fault is more than 90.75% after calibration, the concurrent fault can also reach more than 88.5%. The supply air temperature calibration will make the continuous regulating valve keep the normal opening to maintain the air volume and ensure the stability of indoor temperature. The static pressure calibration will increase the energy efficiency of the supply fan by 17%, make the VAV box adjust normally, and avoid the disorder of the control loops. The differential pressure sensor calibration will increase the energy efficiency of the water pump by 21%, and ensure normal water flow. Meantime, the calibration of three sensors reduces the time to reach a stable state by more than 20.6%. The VIC method based on AE makes the application scenario of sensor fault calibration more extensive and universal.

Experimental study on effect of drying air supply temperature on performance of a quasi-two-stage closed loop heat pump drying system for lentinus edodes

A new closed loop quasi-two-stage enhanced vapor injection heat pump drying system with high drying air supply temperature and simple structure was proposed and built. Firstly, the system operation characteristics including parameters of both heat pump refrigerant and air cycle sides were analyzed. The effects of different drying air supply temperatures on heat pump system drying performance and drying quality for Lentinus edodes were investigated experimentally. The results showed that the maximum drying air supply temperature in the designed system could reach 70 °C. As the drying air supply temperature raised from 40 °C to 70 °C, the drying rate of L. edodes was significantly increased, the average coefficient of performance of the system (COPsys), average specific moisture extraction rate (SMER) and rehydration ratio first increased and then decreased. The average COPsys, average SMER, drying amount per unit energy consumption and rehydration ratio reached the maximum values when the drying air supply temperature was 55 °C, which were 4.19, 0.320 kg/(kW·h), 0.391 kg/(kW·h) and 3.6, respectively. Compared with hot-air drying of L. edodes, the heat pump drying system proposed in this paper also had a significant improvement in the quality (the rehydration ratio increased by more than 45%).

Cooling effect of air movement on heating performances of advanced air distribution

The cooling effect of air movement is widely recognized as an energy-efficient measure for thermal environment management under the cooling mode, but it is generally neglected under the heating mode. This study proposes that the cooling effect of air movement negatively impacts the energy efficiency of advanced air distribution and should be considered when modulating advanced air distribution under the heating mode. Advanced air distribution like stratum ventilation and wall attachment ventilation supplies warm and clean air into the occupied zone by employing supply air momentum to suppress thermal buoyancy. However, the supply air momentum elevates the air movement in the occupied zone and the cooling effect of air movement negatively impacts the energy efficiency of advanced air distribution under the heating mode. Based on numerical simulations validated by the experiments, the results show the cooling effect of air movement significantly impacts the optimal operation, particularly the optimal supply airflow rate of stratum ventilation and the optimal supply air temperature of wall attachment ventilation. Accounting for the cooling effect of air movement can improve the optimal overall performance of advanced air distribution, particularly when the preference for energy efficiency increases. Compared with the optimization ignoring the cooling effect of air movement, the optimization considering the cooling effect of air movement improves the overall performance by up to 38.7% for stratum ventilation and up to 67.6% for wall attachment ventilation. Therefore, the cooling effect of air movement should be considered for modulating advanced air distribution under the heating mode.

Model based development of temperature control schemes for fighter aircraft ECS

The performance of Temperature Control System (TCS), a sub-system of an advanced fighter ECS (Environmental Control System) is studied for its operations both in on-ground and in-air conditions. The standard Bootstrap air cycle system is considered with ACM (Air Cycle Machine) as the main component, which consists of a compressor and a turbine, to produce the cold air. ECS, in particular TCS, is responsible in maintaining the required cockpit or cabin temperature. As the fighter aircraft doesn’t require cabin air recirculation, the cabin temperature depends solely on the supply air thermal conditions. The cabin temperature regulation is realized by controlling the supply conditions by maintaining required temperature at ACM outlet and at the entrance duct to the cabin. These temperatures are critical parameters that necessitates appropriate controller to keep the cabin in a good comfortable state. ECS of a fighter aircraft is highly complex and nonlinear than commercial aircraft. The control logics applied, on this system, will drive the actuators or TCVs (Temperature Control Valves) to keep the requisite cabin temperature. The control logics applied on the controller to be simple and appropriate to meet the requirements of fighter aircraft ECS. This shall minimize the control cycle oscillation and subsequent supply air temperature instabilities. This paper explains novel cabin temperature control schemes and their influence on the ECS performance especially during the transient operation. The complete architecture of the control schemes along with system components are modelled in AMESim and the comparison is made for different operating conditions. Finally, a novel variable time-delay based method to control the cabin supply air temperature is proposed.

Sequential Modeling of Paper Drying Process to Reduce Thermal Energy Use, Part 2: Simulation Results

Paper drying is one of the unit operations that consumes the most amount of thermal energy in a papermaking machine. In this paper, a theoretical model for paper drying process was developed using the sequential modeling method based on the conservation laws of mass and energy. Aimed at simulating thermal energy flow, the overall framework of the drying model was constructed according to the specific drying process of a newsprint machine. It was composed of eight basic modules based on their different functions in the paper drying process, i.e., cylinder group module, steam separation module, surface condensation module, fan module, heat recovery module, air heating module, paper sheet module, and hood module. The results showed that it could be used to simulate the material and energy flow of each module, as well as the whole drying process in a more comprehensive manner with integrated thermal energy use and drying performance information. In addition, the effects of operating parameters, such as supply air temperature and exhaust air humidity, on thermal energy use in the newsprint drying process were also simulated. This work also demonstrates that the sequential modeling method is instructive to reduce thermal energy use for the industrial paper drying process.

Optimization of supply air flow and temperature for VAV terminal unit by artificial neural network

The purpose of this paper is to optimize the supply air flow rate and temperature of the variable air volume (VAV) terminal unit by artificial neural network (ANN). In general, the setpoint of the VAV terminal unit are supply air flow rate and supply air temperature. These setpoints are determined by the design value, and are calculated by the maximum indoor heating/cooling load and the ventilation requirements. The setpoints calculated based on the design value does not cause any problems in maintaining the indoor environment. However, energy consumption cannot be optimized because it is based on the maximum design value. In order to improve the existing control method, it is important to apply the setpoints according to the real time indoor conditions. The real time indoor condition can be utilized for control through prediction model. In this study, the indoor load, indoor air quality and energy consumption were predicted and used for VAV system control. In addition, the predictive model was developed with the ANN algorithm, and the process of selecting input data and optimizing the predictive model was performed. The performance of the ANN based optimal control algorithm (suggested CASE) for the VAV terminal unit in the target building was compared with those of the dual maximum control algorithm (existing CASE), one of the VAV terminal unit control algorithms. The comparison of heating season showed that the ANN based control algorithm of VAV terminal unit reduced 16.7% of supply fan energy consumption and 19.5% of reheat coil energy consumption compared to the existing CASE using the fixed setpoint.

Experimental Investigation on Performance of Multi-Stage Dehumidification Heat Pump Tower Corn Drying System in High Cold Regions

In view of the problems of high energy consumption and heavy pollution in the drying process of large-scale multi-stage tower coal-fired corn in Northeast China, combined with the high cold characteristics of the regions, a multi-stage series dehumidification heat pump tower corn drying system was proposed, and a demonstration application project was established. The performance and life-cycle costs of the system were experimentally evaluated and compared to a traditional coal-fired corn drying tower. The results show that the system can achieve a supply air temperature above 68 °C under the ambient temperature of −20 °C. The total energy consumption of the system per hour is 595.5 kWh, and the specific moisture extraction rate reaches 3.39 kg/kWh. Moreover, the coefficient of performance of heat pump units reaches 3.0 − 6.3. Due to the attractive energy-saving potential, the operational cost-effectiveness of the multi-stage series dehumidification heat pump tower corn drying system can contribute to cut-down of life-cycle cost. It has been found that the life-cycle cost of the multi-stage series dehumidification heat pump tower corn drying system is 40.5% lower than that of the traditional coal-fired corn drying tower.

Distribution of droplets/droplet nuclei from coughing and breathing of patients with different postures in a hospital isolation ward

Suspected and confirmed cases of infectious diseases such as COVID-19 are diagnosed and treated in specific hospital isolation wards, posing a challenge to preventing cross-infection between patients and healthcare workers. In this study, the Euler-Lagrange method was used to simulate the evaporation and dispersion of droplets with full-size distribution produced by fluctuating coughing and breathing activities in an isolation ward. The effects of supply air temperature and relative humidity, ventilation rates and patient postures on droplet distribution were investigated. The numerical models were validated by an aerosol experiment with an artificial saliva solution containing E. coli bacteria conducted in a typical isolation ward. The results showed that the small size group of droplets (initial size ≤87.5 μm) exhibited airborne transmission in the isolation ward, while the large size group (initial size ≥112.5 μm) were rapidly deposited by gravitational effects. The ventilation rate had a greater effect on the diffusion of droplet nuclei than the supply air temperature and relative humidity. As the air changes per hour (ACH) increased from 8 to 16, the number fraction of suspended droplet nuclei reduced by 14.2% and 6.4% in the lying and sitting cases, respectively, while the number fraction of escaped droplet nuclei increased by 16.2% and 14.6%. Regardless of whether the patient was lying or sitting, the amount of droplet nuclei deposited on the ceiling was highest at lower ventilation rates. These results may provide some guidance for routine disinfection and ventilation strategies in hospital isolation wards.

Pseudo-optimal discharge pressure analysis of transcritical CO2 electric vehicle heat pumps due to temperature glide

• A pseudo-optimal discharge pressure for electric vehicle heat pumps was proposed. • The principle of pseudo-optimal discharge pressure was explained. • Pseudo-optimal discharge pressure exists in subcritical and transcritical states. • The effects of conditions on pseudo-optimal discharge pressures were revealed. Performance improvement of electric vehicle heat pumps can enhance thermal comfort and reduce the power consumption of electric vehicles, hence stimulating their development. In this paper, the cyclic characteristics of an electric vehicle heat pump were studied under different operating modes and working conditions. Different from the optimal discharge pressure of conventional CO 2 systems which was determined by the variation gradient characteristics of the transcritical isotherm, the discharge pressure of electric vehicle heat pumps at the peak COP value was defined as a pseudo-optimal discharge pressure and was determined by the obvious temperature glide at the outlet of the gas cooler. This pseudo-optimal discharge pressure existed at both transcritical and subcritical states. The difference in the pseudo-optimal discharge pressure between the subcritical or transcritical states was first evaluated. Then an in-depth analysis of the influence of key parameters on the pseudo-optimal discharge pressure was studied to develop an accurate prediction method since the traditional prediction methods were not applicable. The results showed that pseudo-optimal discharge pressure increased with the ambient temperature, inlet air temperature, and supply air temperature. This study provides valuable information for the comprehensive performance optimization of an electric vehicle thermal management system.

Optimal predictive control of phase change material-based energy storage in buildings via mixed-integer convex programming

This paper describes a mixed-integer convex programming-based control strategy to optimize the operation of phase change material-based energy storage integrated in building supply ducts. To improve the numerical feasibility, the original nonlinear control problem is pre-conditioned and transformed to a mixed-integer convex program through convexification of the cooling system control model, mixed-integer reformulation of the phase change material dynamics and discretization of the supply airflow. The overall control framework was leveraged toward development of two model predictive control strategies to optimally charge/discharge the phase change material storage, through supply air temperature reset, and the building passive thermal mass, via scheduling of the zone air temperature setpoint. These strategies were tested and compared to two baseline control strategies using a simulation case study over three summer days. Test results show that using the phase change material energy storage alone, energy cost savings of 2.9% and peak demand reduction of 46.7% could be achieved, compared to a conventional fixed-supply air temperature and zone air temperature night setup control strategy; when both the active (phase change material) and passive (building thermal mass) storage capacities are utilized, the savings potentials could increase to 8.4% for the energy cost and 65% for the demand charge. • Integration of PCM energy storage in supply ducts is effective in reducing demand. • Predictive control of PCM storage offers significant utility cost savings potential. • Charging/discharging of PCM thermal storage results in efficiency losses. • Combining active and pass storage can provide the maximum load shifting potential.

Numerical simulation of heat pump drying system for paper exhaust hood

Abstract In view of the present situation that the exhaust waste heat of the hot air hood in the paper drying section is too much and the environment is not friendly, a closed heat pump drying system model applied to the exhaust air hood is proposed and established. Effects of evaporation temperature and condensation temperature on supply air temperature, supply air moisture content, system performance coefficient (COP) and dehumidification energy consumption ratio (SMER) were studied. Results show that with the increase of condensation temperature, the supply air temperature is unchanged, and the moisture content of the supply air increase, while the COP and SMER of the system show a downward trend. The moisture content of supply air decrease with the increase of evaporation temperature, while the supply air temperature, COP and SMER all show an upward trend. Therefore, in order to improve the drying characteristics and improve the performance of the heat pump system, the condensation temperature can be reduced and the evaporation temperature can be increased.

Assessment of Thermal Comfort in Rooms Equipped with a Decentralised Façade Ventilation Unit

Thermal comfort affects not only the well-being of the occupants of a building but also the effectiveness of their learning and work efficiency. It can be disturbed if the ventilation airflow is increased when improving indoor air quality. When natural ventilation is used in the fall and winter period, the supply air temperature is low, resulting in a lack of thermal comfort. In existing buildings, there is often no place for mechanical ventilation; hence, decentralised façade ventilation units are increasingly used. The article presents an analysis of thermal comfort in rooms with this type of unit equipped with heat recovery exchangers of different efficiencies. Studies have shown that the alternating supply/exhaust airflow and the related unevenness of air streams flowing through the heat accumulator cause an inflow of low-temperature air, resulting in thermal discomfort. The highest value of the PMV index was −1.6, and the lowest was −4.1, which means that 54.8 to 100% of the occupants are dissatisfied with their thermal comfort. This means there is a need to change the construction of inlet/exhaust vents so that the stream of supply air is not directly parallel to the floor. In addition, the use of an air heater should be considered.

Investigation of supply air parameters of a new method to control the condensation risk in radiant cooling panels

Condensation is prone to occur in radiant cooling systems caused by moisture infiltration through doors and windows. Ensuring condensed droplets evaporate entirely at the end of the shutdown period is critical to the effectiveness of the new adjustment method for metal radiant panels, based on the principle that no dripping occurs. A numerical model of the radiant ceiling system validated by experiment is utilized to explore the evaporation characteristics of surface droplets at different initial radiant panel temperatures and different supply air parameters, and suitable air supply parameters based on indoor thermal comfort are further discussed. According to the simulation results, the evaporation time of droplets decreased to 754s, 746s, and 739s after supplying air at the initial panel temperatures of 18°C, 20°C, and 22°C. Evaporation time is 2971s, 1453s, 739s, 325s, supply air speeds is 0 m/s, 0.5 m/s, 1 m/s, 2 m/s. The mean values of PPD are 15.1%, 5.5%, 17.2%, and 42.6% at supply air temperatures of 24°C, 26°C, 28°C, and 30°C, respectively. Therefore, supplying 26°C of air at a speed of 1 m/s can effectively accelerate the evaporation and meet the indoor thermal comfort. In addition, a new regulation strategy based on PWM is proposed to improve the cooling capacity of the radiant system and maintain a comfortable environment, which can provide some reference for practical operation control.

Energy-efficient air conditioning system using a three-fluid heat exchanger for simultaneous temperature and humidity control

Room air conditioners are unable to simultaneously control the temperature and humidity of the air supply. Although temperature-regulating dehumidifiers can simultaneously control the temperature and humidity, they have complex refrigerant pipelines, and the heat exchanger exhibits air resistance when the reheat demand is low. This study proposes an air conditioning system for simultaneous temperature and humidity control, using a three-fluid heat exchanger. The supply air temperature is adjusted by changing the air volume ratio and cooling water flow rate through the three-fluid heat exchanger, which is used as the condenser. Free cooling can be realized by supplying low-temperature cooling water to treat the return air. Numerical models were built to simulate the performance of the devices in the system, and were validated by experimental results. The temperature-regulating performance and energy consumption under different conditions were numerically calculated using a case-studied air-conditioned room in Beijing. The results are summarized as follows: 1. The proposed strategy can regulate the supply air temperature over a wide range of temperatures. 2. Compared with those of the temperature-regulating dehumidifier system, the compressor and fan energy consumption of the proposed system are reduced by 19.1% and 15.5%, respectively, with a total energy-saving rate of 15.8% in the cooling season. 3. Compared with those of the room air conditioner system, the compressor energy consumption of the proposed system is reduced by 11.5%, and the energy-saving rate of the entire system is 6.3%. The initial investment of the proposed system does not increase significantly compared with conventional systems, and the refrigerant pipeline and valves can be simplified, resulting in acceptable economic performance for the proposed system.

Simulation of CO2 heat pump air conditioning system for new energy vehicle

The CO2 heat pump air conditioning system of new energy vehicle is designed, and the vehicle model of CO2 heat pump module and heat management system is established based on KULI simulation. The effects of refrigerant charge, running time and compressor speed on the heat pump air conditioning system is studied, and the energy consumption is compared with the PTC heating system and the CO2 heat pump air conditioning system without waste heat recovery. The results show that the optimal charge for full-service operation is 750 g; increasing the compressor speed can increase the cooling capacity, so that the refrigerant temperature in the passenger compartment and battery inlet can quickly reach the appropriate temperature, but the COPh, COPc are reduced by 2.5% and 1.8% respectively. By comparing it with PTC heating and CO2 heat pump air conditioning systems without waste heat recovery, it is found that the energy consumption of this system is only for the PTC heating systems 42.5%, without waste heat recovery carbon dioxide heat pump air conditioning system of 86.6%. It greatly saves energy, but also increased the waste heat recovery function, so that the system supply air temperature increased by 26%, improve passenger cabin comfort. This provides a reference for the future experimental research of CO2 heat pump air conditioning and heat management system.