最新刊期
卷 44 ， 期 2 ， 2023
- 摘要：The driven heat and circulating pump in a closed absorption system replaces the compressor in a vapor compression heat pump system and circulates the working fluid while increasing its internal energy, thus saving the compression work from consuming high-grade electric power. Unlike in the closed absorption heat pump (refrigeration) system, in the open absorption system, the indirect heat transfer driven by the temperature difference is replaced with the mass transfer driven by the vapor pressure difference and the heat transfer driven by the temperature difference simultaneously. Heat and mass transfer with the environment can occur in different components (evaporator E, absorber A, generator D, and condenser C) in open absorption systems. For applications in different fields, the structure is simplified based on a closed absorption system, and the performance is optimized. This paper summarizes state-of-the-art open absorption systems in terms of three aspects: working fluid pairs, configurations, and components. Research on the working fluid pairs of open absorption systems has mainly focused on aqueous working fluid pairs with water as the refrigerant. Common salt solutions LiBr-H2O and LiCl-H2O have high performance, but they are corrosive and easy to crystallize. CaCl2-H2O is less corrosive but unsuitable for high-temperature applications. The performance of HCOOK-H2O is between those of LiBr/LiCl-H2O and CaCl2-H2O, resulting in low corrosion to the system. Further experimental studies are required for ionic liquids as potential alternative working fluids. A typical open absorption system has five basic configurations: D, AD, ADC, EAD, and EADC types. The D-type configuration can be used for direct evaporative cooling, refrigeration, and recovery of latent heat from moisture in air. When the evaporation temperature is low in the EAD-type, the evaporator can be used for cooling. In the EAD type, the absorption heat transfer absorber can be used for heating and the generator can be used for humidification. These can also be used for seawater desalination and purification. The ADC-type configuration can be used to recover latent heat from moisture and distillation. The EADC-type open absorption system is similar to the traditional closed absorption system and can be used for refrigeration, heat pumps, and distillation purification. Enhancing the heat and mass transfer between the environment and the system is the focus of the research on open absorption systems. For direct-contact heat and mass transfer components, packed towers are still the main form of adiabatic absorbers/generators. The use of indirect-contact absorption/generation heat exchangers based on membranes is required to fundamentally solve the carryover problem. However, the heat and mass transfer coefficients of the membrane absorption/generation heat exchanger still need to be improved compared with those of direct-contact heat exchangers.关键词：absorption heat pump;review;open absorption;liquid-desiccant dehumidification;heat and mass transfer component;application research1103|1236|0发布时间：2024-07-18
- 摘要：Cooling systems consume a significant amount of energy to ensure the reliable operation of data centers. To help data centers achieve carbon neutrality and fully utilize the energy-saving potential of the cooling system, the energy efficiency of data center cooling systems should be evaluated. Many evaluation indexes of these cooling systems are used in the industry. In this study, the energy efficiency evaluation indexes of data center cooling systems presented in the current standards and literature are investigated, and the related indexes are explored as follows: electric energy utilization efficiency and related indexes of derivative cooling systems, performance indexes of data center cooling systems, and performance indexes of data center cold source equipment. The calculation methods and components of different indexes are introduced, and the advantages and disadvantages of each index are analyzed. Comparative experiments reveal that the power usage effectiveness(PUE) and related derivative indexes of the cooling systems cannot accurately reflect the technical level of the operation and maintenance of the data center. For the energy efficiency evaluation of the actual data center cooling systems, the annual general coefficient of performance(GCOPA) is applicable. For the annual operation index of chillers in Chinese data centers, the annual coefficient of performance(ACOP) is applicable.关键词：data center;cooling system;energy efficiency;performance index1022|1519|0发布时间：2024-07-18
- 摘要：Since the concept of "metaverse" was introduced, it has rapidly become popular in the development plans of national and international governments, local governments, enterprises, experts, scholars, and related researchers. The refrigeration industry is facing development opportunities and challenges in this new area. Thus, there is an urgent need to pave the way for relevant theoretical knowledge and technical updates. This paper presents a review on the background of big data and the relationship between big data and refrigeration in terms of two aspects: the impact of the big data era on the field of refrigeration and the impact of refrigeration technology on the big data era. Big data generates development opportunities in the refrigeration field. In this study, the refrigeration and air-conditioning industry is taken as an example, and the applications of big-data-related technologies for optimizing air-conditioning systems and the digital operation of air-conditioning enterprises are introduced. Refrigeration technology has benefitted from the rapid growth of big data technologies. This study introduces the important role played by refrigeration technology in the construction of cooling systems in data centers of the upstream industry and in solving the heat dissipation problems of downstream terminal products. The analysis provides a reference for understanding the relationship between the metaverse and refrigeration technology. The accumulative power behind the rise of the metaverse era, including boosting force, domestic and foreign layouts, and a better vision, are investigated. Second, the risks in the development process of the metaverse, including computing power risks, addiction risks, ethical issues, intellectual property issues, economic risks, industrial hegemony, and other prominent risks, are objectively analyzed. Opportunities and challenges coexist, which is the distinctive development background of the metaverse era. Finally, this study focuses on the relationship between the metaverse and refrigeration. The metaverse leads to new advancements in the refrigeration field, including a massive demand for refrigeration equipment and a high number of professionals inspired by the large metaverse ecology. Because the metaverse world can provide immersive teaching and vocational training, learning from the “Internet plus” and “Metaverse plus” allows for a transformation and upgrade from physical interactions to “virtual–real” interactions. The influence of refrigeration technology on the era of the metaverse includes meeting the cooling needs for infrastructure and facilities that run the metaverse. More immersive somatosensory experiences, such as skin sensations of heat, cold, and humidity, are enabled by refrigeration technology. Furthermore, infinite possibilities exist for the fusion of the metaverse and refrigeration.关键词：refrigeration technology;metaverse;big data891|985|0发布时间：2024-07-18
- 摘要：Carbon dioxide (CO2) air-source heat pumps have broad application prospects because of their excellent environmental protection potential and thermal performance. In this study, the CO2 cascade air-source heat pump was implemented in distributed central heating systems in a public building in Qinhuangdao City and a residential building in Shijiazhuang City. Both cases were tested and analyzed to explore the uncertainty of measurements and the operation performance in extremely cold conditions as per the Standard for Energy Efficiency Test of Public Buildings JGJ/T 177—2009 and the Standard for Energy Efficiency Test of Residential Buildings JGJ/T 132—2009. Based on the uncertainty analysis, the relative combined standard uncertainty ranges of COP (coefficient of performance) of #2 units operating at various ambient temperatures in Qinhuangdao and Shijiazhuang were found to be 4.27%–5.87% and 1.90%–4.36%, respectively. These ranges reveal that the measurements have high reliability. The measured daily heating COP of #1 and #2 units in Qinhuangdao are 2.75–3.09 and 2.76–3.15, respectively, when the outdoor daily temperature range is -10.9–2.5 °C. Even in the lowest outdoor temperature (-18 °C), the heating COP of #1 and #2 unitscan still reach 2.19 and 2.88, respectively. When #1 and #2 units operate in Shijiazhuang with the outdoor daily temperature being -6.6–12.5 °C, the measured daily heating COP are 2.32–3.38 and 2.21–3.06, respectively. The analysis of these two projects shows that the heating COP of the CO2 cascade air-source heat pump is not sensitive to the ambient temperature in extremely cold conditions.关键词：CO2 cascade air-source heat pump;distributed central heating system;system measurement;uncertainty;COP880|1288|0发布时间：2024-07-18
- 摘要：During reverse-cycle defrosting of an air-source heat pump, the defrosting time is always long owing to insufficient heat sources. For the quasi-two stage compression air-source heat pump (QTASHP), owing to its larger outdoor coil operated at lower ambient temperatures, a considerable amount of heat is dissipated from the surface of the outdoor coil during defrosting, such that the long defrosting time problem becomes more severe. To improve the defrosting performance of the QTASHP, defrosting with vapor injection was proposed based on the existing cycle structure. Five groups of experiments were designed to investigate the defrosting performance. The results showed that vapor injection was beneficial for shortening the defrosting duration, decreasing power consumption, and increasing defrosting efficiency. At the optimal opening of the injection electronic expansion valve, the defrosting duration was shortened by 20.61%; the heat absorbed from water and power consumption decreased by 8.74% and 17.98%, respectively; whereas the defrosting efficiency increased by 6.22%.关键词：air-source heat pump;quasi-two stage compression;defrosting;vapor injection1121|823|0发布时间：2024-07-18
- 摘要：A set of waste heat recovery series-type CO2 heat pump systems is designed for electric vehicles, and the effects of different operating parameters on the low-temperature heating performance of the system are experimentally studied by using a standard enthalpy difference test facility. The results show that the performance of the dual heat source system is better than that of the single source system. The dual heat source mode can optimize the system parameters, increase the heating capacity of the system, and expand the low-temperature working range of the heat pump system. When the ambient temperature is ?20 ℃, the heating capacity and COP of the waste heat recovery mode are increased by 18.9% and 5.9%, respectively. The performance characteristics of the system are analyzed by changing the temperature conditions. The dual heat source mode exhibits more significant advantages in low-temperature environments; as the ambient temperature decreases from ?5 to -20 ℃, the increase ratio of the heating capacity improves from 4.3% to 18.9%, and the increase ratio of COP improves from 4.3% to 5.9%. Thus, it is the best temperature range for using the waste heat mode when the ambient temperature is lower than ?5 ℃. These results guide the practical applications of CO2 vehicle heat-pump systems.关键词：automotive heat pump;CO2 refrigerant;waste heat recovery;heating performance;coefficient of performance913|800|0发布时间：2024-07-18
- 摘要：In this study, we utilize the life cycle assessment method to examine the relationship between the change in the energy efficiency ratio of air conditioners and the energy structure over the course of its operational years. We then develop a carbon emission model for air conditioners based on the dynamic life cycle assessment (DLCA). The carbon emissions of scroll-compressor-based household air conditioners filled with R410A refrigerant are studied. The results show that the introduction of dynamic parameters during operation has a significant impact on the life cycle carbon emissions. Unlike in the static assessment model, the changes in the energy efficiency ratio and energy structure can cause the total carbon emissions to fluctuate by 19.0% and -9.1%, respectively. The annual carbon emissions at the end of the air conditioning service life of the dynamic and static assessment models are 1.71 and 0.80 times the initial annual carbon emissions, respectively. The life cycle carbon emissions of air conditioners are mainly produced during the operation stage, accounting for 91.8% of the total emissions; 75.0% of the total carbon emissions in the life cycle is caused by the power consumption of equipment operation and 23.0% is from refrigerant leakage. Parameters such as the indoor temperature setpoint, refrigerant leakage rate, and refrigerant GWP have a significant impact on carbon emissions during the life cycle of an air conditioner. This study will contribute to the further optimization of carbon emission evaluation models in the HVAC field.关键词：air conditioner;carbon emission;life cycle assessment;refrigerant;energy efficiency ratio669|823|0发布时间：2024-07-18
- 摘要：The determination method for the annual performance factor (APF) of the air conditioner energy efficiency index given in the national standard involves a series of evaluations and nested calculations, and the process is complex. The objective of this study is to convert the APF calculation formulas given in the new National Standard GB 21455—2019 into explicit calculation expressions, meeting the requirements for convenient APF calculation. The adopted method is as follows: first, the four intermediate variables of the APF are simplified by directly substituting independent variables; then, the process of determining the calculation interval and segmental calculation is simplified by means of numerical fitting; finally, the APF explicit expressions are obtained by substituting the explicit expressions of the four intermediate variables into the APF definition. The developed APF explicit expressions apply to variable-frequency air conditioners with different rated cooling capacities with good accuracy. Based on the definition of the APF in the National Standard, the calculation errors of the explicit expression for the 5-test working conditions and 7-test working conditions are 0.73% and 1.17%, respectively.关键词：APF;air conditioner;rapid calculation;explicit expression;energy efficiency standard for air conditioners864|861|0发布时间：2024-07-18
- 摘要：At present, only a few studies on multi-stage thermoelectric coolers are available, and reports on the cooling performance of such coolers are not consistent. To study the performance of multi-stage thermoelectric coolers, a multi-physics simulation model of single-stage to six-stage thermoelectric coolers is developed based on the physical parameters of commercial-grade thermoelectric materials in this study, and the accuracy of the model is verified experimentally. In terms of the design of the multi-stage thermoelectric cooler, the influences of the external drive circuit and internal structural parameters on its cooling performance are studied. The results show that when the hot end is 27 °C, the six-stage thermoelectric cooler can obtain the maximum cooling temperature difference of 113.32 °C, 71.84 °C, and 129.78 °C using the electrical series, electrical parallel, and independent power drive circuits, respectively. The optimal applications of different driving circuits are further explored, and the causes for the differences in the cooling performance of the multi-stage thermoelectric coolers under different driving circuits are analyzed. A six-stage thermoelectric cooler is taken as an example, and the influence of the thermoelectric leg height of each stage is explored. The results show that the leg height of the highest stage is the most important factor.关键词：thermoelectric refrigeration;simulation model;drive circuit;thermoelectric leg height;refrigeration performance853|714|0发布时间：2024-07-18
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Effects of the Heat Exchanger Tube Spacing on the Heat Transfer Performance of Cold Radiation Panels
摘要：Cold radiant air conditioners are increasingly valued for their better thermal comfort and greater energy-saving potential, but their likeliness to condensate and low cooling heat flux negatively affect their engineering applications. By establishing a model of the heat transfer process of a metal radiation panel, the influences of the radiation panel heat exchanger tube spacing on heat transfer performance were analyzed. This study found that when the water supply temperature and flow rate were held constant at 17 °C and 0.3 m/s, respectively, reducing the tube spacing of a 1.2 m × 0.4 m copper tube radiant heat exchange surface from 100 mm to 68 mm resulted in a decrease of 0.58 °C in the average surface temperature and 0.76 °C in the maximum surface temperature of the radiant panel. Additionally, it resulted in a decrease of 3.56% in the temperature homogeneity coefficient and 9.41% in the maximum temperature homogeneity coefficient for a conventional equal tube spacing arrangement. Based on these findings, a total of nine types of radiation panels were designed, including three types of variable tube spacing arrangements with 4, 5, and 6 rows. Comparison with the corresponding equal tube spacing arrangement of radiation panels showed that the highest average surface temperature decreased by 0.37, 0.56, and 0.36 °C, respectively, and the highest temperature homogeneity coefficient decreased by 19.3%, 23.5%, and 30.3%, respectively. This highlights that the variable tube spacing arrangements for heat exchanger tubes lead to a more uniform surface temperature.关键词：cold radiant panel;variable tube spacing;average surface temperature;temperature homogeneity coefficient796|890|0发布时间：2024-07-18 -
Heat Transfer Characteristics of Condensers in Rotating Heat Pipe Grinding Wheel under Impinging Jet
摘要：An axial rotary heat pipe grinding wheel is a new type of grinding wheel used to strengthen the heat transfer in the grinding arc area. Its heat transfer performance directly affects the heat transfer performance of the entire heat pipe grinding wheel. In this study, the condenser of the heat pipe grinding wheel was designed in conjunction with the condenser design method, and the heat transfer performance of the axial rotating heat pipe grinding wheel condenser was analyzed using a numerical simulation model to optimize the structural parameters of the condenser of the rotating heat pipe grinding wheel. The effects of different fin heights (f = 0–8 mm), nozzle-to-fin top distances (d = 3–11 mm), low-temperature air jet velocities (vj = 45–115 m/s), and grinding wheel speeds (n = 150–1 180 r/min) on the heat transfer performance of the condenser were investigated. The results showed that the best heat transfer coefficient of 459 W/(m2·K) was obtained when the fin height was 6 mm, in which the convective heat transfer coefficient was increased by 36% compared with the finless structure. The best heat transfer performance was obtained when the distance from the nozzle to the top of the fin was 5 mm, and the heat transfer coefficient was 459 W/(m2·K). When the low-temperature air jet velocity increases, the convective heat transfer coefficient increases. The highest heat transfer coefficient is achieved at a jet velocity of 115 m/s, up to 459 W/(m2·K), which is 43% higher compared to the jet velocity of 45 m/s. When the grinding wheel speed increases, the convective heat transfer coefficient also increases. The highest heat transfer coefficient is achieved at a speed of 1 180 r/min, up to 459 W/(m2·K), which is 4% higher than the speed of 150 r/min.关键词：heat transfer coefficient;condenser;rotating heat pipe grinding wheel;impinging jet719|695|0发布时间：2024-07-18 - 摘要：This paper presents an experimental study and a model for the oil retention and flow pattern of an R32/PVE 68 mixture in compressor suction lines. The test conditions involved a saturation temperature of 7.5 ℃ and a superheat degree of 12 ℃. The refrigerant mass flux and nominal oil mass fraction (OMFno) were varied within the ranges of 90–230 kg/(m2·s) and 0%–5%, respectively. The test samples were two smooth copper pipes with horizontal and vertical flow orientations with an inner diameter of 10.7 mm. A high-speed camera was used to record the flow pattern. The results showed that when the mass flux was from 90 to 120 kg/(m2·s) and the flow pattern was a stratified wavy flow, the amount of oil retention decreased with an increase in mass flux; in other cases, the amount of oil retention increased with an increase in mass flux. When the oil mass fraction was 1% and the mass flux reached 160 kg/(m2·s), the flow pattern changed to a wavy annular flow and gradually developed into an annular flow. The double-circle model based on the flow pattern was used to predict the oil retention in the suction line. The results showed a mean absolute deviation of 9.35%, and 87.83% of the data were within ±20% error. To further verify the applicability of the model, 291 data points were collected from five open literature, achieving a mean absolute deviation of 12.90% and a maximum absolute deviation of 65.77%, which proves that the model can accurately predict the oil retention in the suction line.关键词：refrigerant;lubricant oil;oil retention;suction line;modeling763|850|0发布时间：2024-07-18
- 摘要：With carbon neutrality becoming the strategic goal leading the sustainable development in China, reducing energy consumption and improving the efficiency and purification efficiency of HVAC systems are urgent issues that need to be resolved in the new era. The gas-liquid heat and mass transfer performance of TiO2-Ag nanofluid was investigated; the heat and mass transfer characteristics of nanofluids in different fluent states such as “bubbling” “spraying” and “filling” were explored; and the effects of the system parameters on the enhancement of heat and mass transfer were analyzed. The results show that the bubbling condition has a better gas-liquid heat transfer effect than the spray and filling conditions. Consequently, the setting of the gas flow rate should consider both the stability and gas-liquid contact time to obtain the best heat and mass transfer effects. Therefore, in this experiment, the optimal inlet gas flow rate was set to 4 L/min. The system showed an effectively enhanced heat and mass transfer and could serve as a significant reference for engineering applications.关键词：nanofluids;TiO2-Ag;heat transfer enhancement;air purification768|753|0发布时间：2024-07-18
- 摘要：Complex heat and mass coupleding transfer phenomena exist in a solid dehumidification cycle, where the adsorption heat released by the desiccant during the adsorption stage will reduce dehumidification performance, while ideal isothermal dehumidification can eliminate this negative effect. To investigate the mass transfer characteristics of the silica gel desiccant coating under an isothermal dehumidification process, the heat and mass transfer was decoupled, and a two-dimensional conjugated heat and mass transfer numerical model validated by the isothermal dehumidification experimental results of isothermal dehumidification was developed. Simulations were conducted to study the impact of air velocity and desiccant layer thickness on the movement of matter. These two factors, namely, air velocity and desiccant layer thickness, affect the resistance of matter mass transfer on both the air and solid sides. The results show that an increase in air velocity strengthens the air-side mass transfer capacity, resulting in a relatively stronger effect of the solid-side mass transfer resistance on the total mass transfer process. As a result, both Sh and 〖Bi〗_m increased during the adsorption and desorption processes. As the thickness of the desiccant layer increased, the solid-side mass transfer resistance increased, thereby reducing Sh and increasing 〖Bi〗_m for the adsorption and desorption processes. In particular, both air-side and solid-side mass transfer resistances should be accounted for in the numerical modeling of the dehumidification cycle for desiccant coatings usually requires the simultaneous effects of air- and solid-side mass transfer resistances.关键词：dehumidification;adsorption heat pump;heat and mass transfer;numerical simulation695|817|0发布时间：2024-07-18
- 摘要：To investigate the temperature distribution and optimize the thermal performance of a vehicle carriage for transporting refrigerated vaccines, a 3.9 m3 vehicle carriage working within the temperature range of 2–8 °C is examined in this study. Four factors, namely, solar radiation intensity, air duct structure, refrigeration unit switch, and door curtain, which influence the thermal performance, are experimentally studied at a compressor speed of 1 800 r/min. The uniformity of the temperature distribution and the temperature change rate during the measurement period are comprehensively analyzed. The results show that when the vaccine refrigeration vehicle is maintained under an average solar radiation intensity of 295.94 W/m2and 82.78 W/m2 for two hours, the average temperature in the carriage under the former condition is 1.326 °C higher than that under the latter. The on-off frequencies of the refrigeration units increase, and the energy consumption of the vehicle increases. The application of the air duct structure can help reduce the local hot spots in the carriage, and the rate of pre-cooling increases by 0.006 °C/s. Moreover, when the carriage door is opened for 120 s, continuous operation of the refrigeration unit enhances the airflow heat exchange between the inside and outside of the carriage, which noticeably disturbs the temperature distribution in the vehicle. Therefore, closing the refrigerating unit is recommended when the vehicle door is opened. The curtain can effectively prevent cold air from exchanging heat with the environment and maintain the low temperature of the carriage.关键词：refrigerated vehicle;vaccine;thermal performance;temperature field920|786|1发布时间：2024-07-18
- 摘要：In cold store facilities, such as cold rooms and fresh storage warehouses, air curtains are usually installed at the door to reduce the loss of cooling capacity caused by opening the door during operation. Traditional air curtains have disadvantages such as high wind speed attenuation and poor sealing performance. Therefore, in this study, three structurally independent design are developed, aiming to optimize the wind speed through the air curtain device as follows: an improved small static pressure box and the tapered nozzle is installed, guide vanes are installed in the static pressure box, and the return air system is installed. Additionally, an optimization of the air curtain airflow organization and the sealing effects of the cold storage are studied. The wind speed at various points of the air curtain's outlet section is measured to determine the decrease in the wind speed as it traveled 1.2 m from the outlet. The effectiveness of the air curtain in sealing a warehouse door is also evaluated by using a gas tracer method to examine cold air penetration under different configurations of the air curtain system. The results show that the installation of the static pressure box and tapered nozzle significantly increases the wind speed in the first half of the air supply, and the installation of the guide vanes has a greater impact on the wind speed in the second half of the wind speed storehouse door. The return-air system increases the wind speed in the second half. The sealing efficiencies of the single-layer air curtain, double-layer air curtain, and three-layer air curtain in the cold air penetration experiment are 0.16, 0.19, and 0.22, respectively, and those of the single-layer circulating air curtain, double-layer circulating air curtain, and three-layer circulating air curtain are 0.29, 0.38, and 0.43, respectively.关键词：air curtain;airflow organization;wind speed attenuation;cold air penetration881|931|0发布时间：2024-07-18
- 摘要：The low-temperature transportation of biological products necessitates urgent demands for the cold storage function of portable low-temperature freezers. In this study, experimental tests were conducted to investigate the temperature changes in a Stirling low-temperature freezer with a low-temperature phase change material (PCM) during power failure. Based on the test results, a three-dimensional numerical model was developed to further analyze the effect of the height ratio of the side-swing arrangement of the cold plate on the air temperature in the freezer and the phase transition of the PCM. The experimental results showed that when the ambient temperature was 20 °C, the central temperature of the freezer without the PCM required 0.26 h to rise from -86°C to -70 °C, whereas the central temperature of the freezer loaded with 3.2 kg PCM (EO-75) required 5.33 h to rise from -86 °C to -70 °C. The simulation results showed that the height ratio of the side-swing arrangement of the cold plate had an important effect on the freezer temperature. When the height ratio of the cold plate increased from 50% to 90%, the time of keeping the central temperature at -86 °C to -70 °C was extended from 2.96 h to 7.66 h, and the cooling efficiency of the PCM increased from 29.18% to 48.28%. The height ratio of the cold plate should be 90%. The results of this study can be useful in the research on low-temperature cold chain transportation technology.关键词：low-temperature freezer;phase change material;numerical simulation;temperature distribution769|949|0发布时间：2024-07-18
- 摘要：In this study, a simulation model of a natural cold source-based refrigerated display cabinet system is established by using the TRNSYS software. First, the air supply temperature of the display cabinet and the cooling temperature of the coolant are selected as variables, and the annual energy consumption is considered as the assessment index to optimize the operating conditions of the natural cold source-based refrigerated display cabinets for food storage. Second, the operating characteristics of the system are analyzed based on optimization and compared with the energy consumption of traditional food refrigerated display cabinets. The results show that the annual energy consumption of the optimal working condition system is the lowest (11 506 kW?h) when the air supply temperature of the display cabinet and the cooling temperature of the coolant is -1.5 °C is -3 °C, respectively. Compared with the traditional food refrigerated display cabinets without a natural cold source, the energy consumption of this system is reduced by 40.8%. In the optimum working conditions, the total operating time of the natural cold source-based cold thermal energy storage cooling mode and the natural cold source-based separate cooling mode is 3 739 h, accounting for 42.7% of the total running time during the entire year; the COP (coefficient of performance) of the system is 3.9, and the COP of the refrigeration unit is 4.1.关键词：refrigerated display cabinet;system energy saving;TRNSYS;natural cold source808|786|0发布时间：2024-07-18
- 摘要：Liquid-cooling technologies show substantial prospects as heat load increases in data centers. In this study, a single-phase liquid-cooling cabinet is established. In terms of servers and cabinets, the following important parameters are investigated: structure factors, operating parameters, and physical parameters of the coolant. The results show that high-performance radiators and reliable internal structures can effectively promote the cooling performance of the cabinet. Increasing the flow rate can improve the performance of this system, at the cost of an increased pressure drop. The baffle can force the coolant to flow into the server and significantly reduce the CPU temperature. The change in the CPU temperature before and after adding the baffle is 19.8 °C. The conclusions of this study can provide guidance for the design of single-phase immersion data centers.关键词：single-phase immersion liquid cooling technologies;servers;liquid-cooling cabinets;numerical simulation982|1088|0发布时间：2024-07-18
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