Preparation and Performance of n-Dodecane Microencapsulated Phase Change Cold Storage Materials

Cold chain transportation is currently a hot research topic.Since the traditional refrigeration methods lead to the consumption of large amounts of energy,the search for new energy storage materials is a major trend.In the present contribution,n-dodecane/PMMA microencapsulated phase change materials were prepared by suspension polymerization for ice-temperature cold chain transportation and their preparation parameters were explored using the encapsulation ratio as optimization indicator.The results show that the n-dodecane-containing microcapsules have a maximum encapsulation ratio of 93.2%when using a core-to-wall ratio of 3:1,5%of emulsifier,30%of crosslinker,and 2000 rpm of emulsification speed.The phase transition temperature and enthalpy are-2℃and 195.9 kJ/kg,respectively.The microcapsules prepared with the optimized process parameters have good microscopic morphology,high energy storage efficiency,uniform particle size and good thermal stability,making them ideal materials for cold chain transportation.

Spatial Pattern Evolution and Influencing Factors of Cold Storage in China

Cold storage is the vital infrastructure of cold chain logistics. In this study, we analyzed the spatial pattern evolution characteristics, spatial autocorrelation and influencing factors of cold storage in China by using kernel density estimation(KDE), spatial autocorrelation analysis(SAA), and spatial error model(SEM). Results showed that: 1) the spatial distribution of cold storage in China is unbalanced, and has evolved from ‘one core’ to ‘one core and many spots’, that is, ‘one core’ refers to the Bohai Rim region mainly including Beijing, Tianjin, Hebei, Shandong and Liaoning regions, and ‘many spots’ mainly include the high-density areas such as Shanghai, Fuzhou, Guangzhou, Zhengzhou, Hefei, Wuhan, ürümqi. 2) The distribution of cold storage has significant global spatial autocorrelation and local spatial autocorrelation, and the ‘High-High’ cluster area is the most stable, mainly concentrated in the Bohai Rim;the ‘Low-Low’ cluster area is grouped in the southern China. 3) Economic development level, population density, traffic accessibility, temperature and land price, all affect the location choice of cold storage in varying degrees, while the impact of market demand on it is not explicit.

Nitric Oxide Regulates Mitochondrial Fatty Acids and Promotes CBF Expression of Peach Fruit during Cold Storage

Low-temperature storage is convenient for postharvest preservation of peach fruit,but peach fruit is sensitive to cold damage,which lowers its quality.Nitric oxide(NO)has the potential to improve the bitter resistance of peach fruit.In this work,peach fruit was treated with 15μmol L^(−1)NO and 5μmol L^(−1)c-PTIO[2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxo-3-oxide],to study changes in mitochondrial fatty acids and expression of the C-repeat binding factor(CBF).The results showed that 15μmol L^(−1)exogenous NO significantly maintained fruit quality,reduced peroxidation of mitochondrial fatty acids,increased the activities of the antioxidants superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),ascorbic acid peroxidase(APX),and reduced the content of hydrogen peroxide(H_(2)O_(2)).Meanwhile,NO treatment suppressed the increase in browning index and ion leakage rate,increased the activity of S-nitrosoglutathione reductase(GSNOR),the contents of S-nitrosothiols(SNOs),and the ratios of mitochondrial NAD^(+)/NADH and NADP^(+)/NADPH,increased the expression levels of PpCBF1/5/6.However,the expression levels of PpCBF2/3/4 were not significantly regulated by exogenous NO.Peaches treated with c-PTIO showed opposite effects to those treated with exogenous NO.These results suggest that exogenous NO can improve antioxidant capacity,preserve mitochondrial fatty acids,and upregulate the expression of PpCBF1/5/6 to alleviate cold tolerance and maintain the peach quality during storage.

Prospects and Challenges of Utilizing Solar Energy for the COVID-19 Vaccine Cold Storage in Remote Clinics of Tropical Countries:Review

The rapid spread of COVID-19 pandemic has forced several countries in the world to store vaccines in cold storage towards ensuring their protection from being damaged and to maintain their stability.However,most remote clinics,especially those in the equator and islands,are faced with the challenges of hot climates and the inability to afford electricity resources needed to power the cold storage facility.Meanwhile,the hot equatorial region has abundant solar energy to power the vaccine cold storage but previous studies showed that several field workers do not have the ability to maintain the vaccine storage temperature as indicated by the manufacturer’s recommendations.Therefore,this literature review study examines the prospects and challenges of implementing solar-powered cold storage to provide cooling space for remote clinics.This is expected to contribute significantly to cold chain vaccine management technology.The findings showed that four technology integration schemes including Cold Storage Ice Maker,Cold Storage Ice Maker-PCM,Refrigerator-Ice Maker and,Absorbing Cooling-PV-Ice Maker have the potential to be applied in clinics situated in certain tropical regions.

Modeling of seasonal soil cold storage using natural cold energy

To reduce energy consumption on summer air conditioning,a novel seasonal soil cold storage mode using natural energy is presented and two-dimensional transient heat transfer model of U-tube is developed. The three processes of cold storage in winter,shut-down in transition season and cold extraction in summer are simulated by using sensitive heat capacity method with variable time step. The changing of U-tube outlet water temperature in different periods,daily cold storage and cold extraction are estimated. The temperature field of the U-tube and soil around the tube is investigated. Simulations show that seasonal soil cold storage using natural cold energy is feasible in the north to Changchun,which provides theoretical support for seasonal soil cold storage application.

Evaluation of myocardial viability during cold storage by measurement of myocardual dielectric properties tanδm in radio frequency

Objective To study the mechanism of myocardial dielectric property changes in radio frequency during hypothermic preservation and explore myocardial viability evaluative method. Methods Hybrid young pigs ( 20 - 30 kg) were used in the experiment. Heart arrest was in-

The influence of aprotinin on the mRNA expression of P-selectin and ICAM-1 in the in situ lung tissue after ischemic cold storage and reperfusion

To explore the influence of aprotinin on the mRNA expression of P-selectin and ICAM-1 in lung tissue after ischemic reperfusion.Methods Thirty New Zealand white rabbits were randomly divided into 3 groups:control group,LPD group and aprotinin group.In situ rabbit lung preservation model was established.In control group,the left lower lung lobe was stored at 10℃ in a specially made lung preservation container for 2 hours and reperfused for another 2 hours.In LPD group and aprotinin group,the left lower lobe was perfused with LPD solution or aprotinin containing LPD solution,respectively,after left lung hilus was clamped.The other procedures were the same as those in control group.The lung tissue was harvested at different time intervals including preclamping lung hilus,2 hours after clamping and 2 hours after reperfusion.The mRNA expression of ICAM-1 and P-selectin in the lung tissue was detected with RT-PCR technique.Results The contents of mRNA of P-selectin at 2 hours after reperfusion in control group and LPD group were significant higher than pre-ischemia and 2 hours after champing the left lung hilus.There was no such significant difference in aprotinin group.The mRNA expression of P-selectin in aprotinin group at 2 hours after reperfusion was significantly lower than that in control group and LPD group.The ICAM-1 mRNA expression at 2 hours after Ischemia and 2 hours after reperfusion in control group and LPD group was significantly higher than the pre-ischemia and its was significantly higher than that in aprotinin group.Conclusion Aprotinin can inhibit the upregulation of the mRNA expression of P selectin and ICAM-1 after ischemia reperfusion in the lung tissue,so the addition of aprotinin in LPD solution may reduce the ischemia reperfusion injury in lung tissue.5 refs,1 tab.

Numerical investigation of a latent cold storage system using shell-and-tube unit

The use of cold thermal storage systems in low-temperature industrial applications is considered one of the most promising ways of improving energy efficiency and reducing the use of power during peak periods.In this study,the thermal performance of a shell-and-tube cold storage system under realistic operating conditions is investigated numerically.The proposed model is developed based on energy balances and then validated using existing experimental data from the literature.Glycol/water is used as the heat transfer fluid(HTF)and the phase transition phenomena in the phase change material(PCM)is simulated using the enthalpy-porosity approach.The influence of several design and operating parameters,including the HTF mass flow rate,HTF temperature,PCM type,and volume,on the cold storage performance during the crystallization process is presented and analyzed.The numerical results show that increasing the HTF mass flow rate accelerates the PCM crystallization process.However,the delivery periods of constant thermal power and constant HTF outlet temperature are reduced.The HTF inlet temperature has a significant effect on the cold storage performance,and the complete charging period is reduced by approximately 37%when the HTF inlet temperature is reduced from−4°C to−7°C.Increasing the number of tubes in the cold storage unit is concluded to significantly improve the thermal performance of the system,and using water/ice as a cold storage medium is more suitable than using the commercial PCMs RT2-HC and RT4-HC.Finally,the proposed numerical model for cold storage systems can be successfully used to design and simulate their realistic operation under different conditions.

Optimal Design of Grid-Connected Microgrid System for Cold Chain Logistics Centre in China

The growing interest in energy conservation has inspired companies to seek alternatives to highly polluting fuel electricity generation. This study designed an optimised solar wind power generation system to fulfil the energy requirement of a cold chain logistics centre. This study first conducted a thorough analysis of the clarity indicators and daily temperature positions of the cold chain logistics centre, determined the average daily electricity demand, and proposed an effective design scheme. The energy simulation software, RETScreen 8.0, was used to determine the scale of solar photovoltaic and wind power projects that meet the expected energy needs of the cold chain logistics centre. The results indicated that the estimated annual total energy demand was 833689.2 kWh. The annual power generation of 6 kW from solar photovoltaic projects and 150 kW from wind power projects was found to be enough to meet the expected electricity demand. Solar photovoltaic power generation and wind power generation account for 2.44% and 97.56%, respectively. The hybrid energy system achieved a 96.6% reduction in carbon emissions and provides a reasonable payback period of 6.1 years and an electricity generation of 904368.674 kWh per year. The feasibility of the project and the calculated period of investment return are very reasonable. Therefore, this hybrid renewable energy system provides reliable power by combining energy sources.

Effects of Co-60 gamma-irradiation and refrigerated storage on the quality of Shatang mandarin

The effectiveness of Co-60 gamma irradiation in controlling citrus red mite(Panonychus citri McGregor)had been proved in our earlier work.However,whether it could be used as an alternative method to replace the current way of quarantine treatment against citrus red mites depends on the performances of effective doses on citrus fruits.This study was conducted to explore the effects of Co-60 gamma irradiation on the nutrient composition of citrus(Shatang mandarin);selected fruits were divided into different groups and each group was irradiated at 0.0,0.2,0.3,0.4,0.5,and 0.6,respectively.And then the treated fruits were stored at 4◦C and the nutrient composition was studied in the following days.The results showed that the shelf-life could be extended when fruits were irradiated in the dose range of 0.2–0.4 kGy,while most unirradiated citrus decayed by 15 d.It also turned out that the citrus irradiated at 0.5 and 0.6 kGy were fully decayed within 45 d of refrigerated storage.The content of total soluble solids(TSS),total sugar,ascorbic acid(AA),and titratable acidity had no significant differences compare to those of the control during the 15 d storage period.Nevertheless,the activities of peroxidase(POD)and superoxide dismutase(SOD)decreased after 15 d;the improvement of storage quality and shelf life may be explained by the change of the protective enzyme activity.In conclusion,the results of citrus fruit treated with irradiation at a certain dose indicated the potential use of Co-60 gamma irradiation as a safe quarantine treatment.©2014 Beijing Academy of Food Sciences.Production and hosting by Elsevier B.V.All rights reserved.

Effects of Different Storage Treatments on Physicochemical Indexes of Green Plums

[Objectives]This study was conducted to discuss the change laws and relationships of the physiological indexes in green plums treated with nisin or 1-MCP in the cold storage process.[Methods]Different storage methods on the physiological and quality indexes of green plums were investigated through two kinds of different treatment methods(treatment 1:1-MCP+cold storage,treatment 2:nisin+cold storage),with rotten fruit rate,weight loss rate,yellow ripeness index,hardness,Vc content,titratable acid,soluble solids and peroxidase(POD)activity as the evaluation indexes.[Results]The storage method of treating green plums with 1-MCP combined with cold storage could delay the quality decline of green plums after harvest,while the effect of nisin treatment was slightly inferior.1-MCP treatment followed by cold storage could more effectively delay the senescence of green plums,delay the decrease of fruit hardness and soluble solid content to the greatest extent,and maintain the titratable acid and Vc contents at relatively good levels.It further reduced weight loss rate and rotten fruit rate,postponed the time of the peak of POD enzyme activity,and reduced the loss of nutrients in the fruit,thereby maintaining good commercial properties of the fruit.[Conclusions]This study plays an important role in the post-harvest storage,preservation and transportation,as well as the development of the green plum industry.

Research progress of mobile cold storage using ice slurry

The demand for cooling,such as that of products,spaces,and processes,has increased with the development of urbanization.Cold storage can shift the valley time of electric power to cold energy.Compared to the fixed cold storage routine,mobile cold storage can eliminate site limitations.Ice slurry,as a new functional fluid,has recently become a new source of technology in our social lives.First,the research status of ice slurry mobile cold storage is summarized.Applications in the engineering field,such as space cooling,fisheries,pipeline cleaning,firefighting,and other real scenarios,are listed.Subsequently,key issues are summarized to understand the theoretical basis of ice slurry mobile cold storage,including flow,heat transfer,and loss in the mobile cold storage process-related ice slurry.Both tap water ice slurry and binary ice slurry are distinguished and discussed.Finally,beneficial policy analyses and market prospects for its promotion are presented.In summary,ice slurry mobile cold storage is a popular research topic with broad prospects for energy storage.

Melatonin treatment alleviates chilling injury in mango fruit 'Keitt' by modulating proline metabolism under chilling stress

Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.Therefore,advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a higher value.This study addresses chilling stress modulation by investigating the effects of melatonin treatment on CI,proline metabolism,and related gene expressions of ‘Keitt’ mango during cold storage after dipped in 0 (control),0.1 (MT1),and 0.2 mmol L^(-1)(MT2) melatonin solution for 30 min.The results revealed that melatonin treatment in MT1 significantly reduced CI development and increased proline content in mango fruit during cold storage compared to the control.These changes were along with increases in the activity of critical enzymes as well as the expression of encoding genes involved in proline biosynthesis,such as pyrroline-5-carboxylate synthetase (P5CS),pyrroline-5-carboxylate reductase (P5CR),ornithine D-aminotransferase (OAT),P5CS2,P5CR2,and OAT3.Additionally,proline dehydrogenase (PDH) activity and the expression of the PDH3 gene associated with proline dehydrogenation were lower in MT1-treated mangoes than the controlled group.Thus,melatonin treatment has regulated proline metabolism resulting in the accumulation of proline,subsequently contributing to enhancing the chilling tolerance of‘Keitt’mango fruit.

4E analysis and optimization of cold thermal-energy storage under partial operating mode and demand-limiting mode for air-conditioning systems

Cold thermal energy storage is an active method for reducing the peak electrical demand and electricity consumption of air con-ditioners.This paper investigates two different cases:partial operating mode-load levelling(POM-LL)and demand-limiting mode(DLM).4E(energy,exergy,economic,environment)analyses along with a multi-objective optimization process based on a genetic algorithm is applied to determine optimal design values.Exergy efficiency,total annual cost and payback-period time are considered as objective functions in this study.The results have shown that POM and DLM decreased the electricity consumption by 10.36%and 11.29%,respectively,resulting in raising the annual costs by 11.08%and 11.42%.Also,their annual payback periods were 4.36 and 4.18 years each.In addition,using off-peak hours instead of on-peak hours for electricity consumption and reducing electricity consump-tion are the two main ways of decreasing CO_(2) emissions during electricity generation.Therefore,the CO_(2) emissions through POM and DLM are 13.31%and 13.72%less than those of conventional systems,respectively.

A fully solid-state cold thermal energy storage device for car seats using shape-memory alloys

Thermal energy storage has been a pivotal technology to fill the gap between energy demands and energy supplies.As a solid-solid phase change material,shape-memory alloys(SMAs)have the inherent advantages of leakage free,no encapsulation,negligible volume variation,as well as superior energy storage properties such as high thermal conductivity(compared with ice and paraffin)and volumetric energy density,making them excellent thermal energy storage materials.Considering these characteristics,the design of the shape-memory alloy based the cold thermal energy storage system for precooling car seat application is introduced in this paper based on the proposed shape-memory alloy-based cold thermal energy storage cycle.The simulation results show that the minimum temperature of the metal boss under the seat reaches 26.2°C at 9.85 s,which is reduced by 9.8°C,and the energy storage efficiency of the device is 66%.The influence of initial temperature,elastocaloric materials,and the shape-memory alloy geometry scheme on the performance of car seat cold thermal energy storage devices is also discussed.Since SMAs are both solid-state refrigerants and thermal energy storage materials,hopefully the proposed concept can promote the development of more promising shape-memory alloy-based cold and hot thermal energy storage devices.

Experimental research and numerical simulation of the thermal performance of a tube-fin cold energy storage unit using water/modified expanded graphite as the phase change material

In this study,experimental and numerical investigations were conducted on a tube-fin heat-exchanger latent-heat cold energy storage unit.The fin side of the heat exchanger was filled with water as the energy storage medium,and modified expanded graphite(MEG)was employed to improve the thermal characteristics of water.The water contact angle of the expanded graphite decreased from 106.31°to 0°,and the hydrophilicity and the absorption rate of water significantly improved after the modification.Moreover,the experimental analyses of the charge/discharge process showed that the cooling capacity of the system filled with 90 wt.%water/MEG was 80.8%of that of pure water,whereas its cooling time was only 69.7%of that of pure water.The average power increased by 15.9%compared with that of water.The system filled with 90 wt.%water/MEG completed two energy charging and discharging cycles,whereas the system filled with water completed only 1.5 cycles within 15000 s.Furthermore,the effects of the flow rate and inlet temperature of the heat transfer fluid on the charging process were explored.Finally,a numerical model was built and validated to investigate the phase change behavior and the effect of the structure size on the performance of the system.The heat-exchanger fin spacing had no significant effect on the cold energy storage unit,whereas the vertical spacing of the tube pass had the highest effect.It can be concluded that the heat exchanger combined with high-thermal-conductivity water/MEG exhibits better energy storage capacity and working power,showing a wide application prospect in the field of cold energy storage.

Numerical simulation of underground seasonal cold energy storage for a 10 MW solar thermal power plant in north-western China using TRNSYS

This paper aims to explore an efficient, cost-effective, and water-saving seasonal cold energy storage technique based on borehole heat exchangers to cool the condenser water in a 10 MW solar thermal power plant. The proposed seasonal cooling mechanism is designed for the areas under typical weather conditions to utilize the low ambient temperature during the winter season and to store cold energy. The main objective of this paper is to utilize the storage unit in the peak summer months to cool the condenser water and to replace the dry cooling system. Using the simulation platform transient system simulation program (TRNSYS), the borehole thermal energy storage (BTES) system model has been developed and the dynamic capacity of the system in the charging and discharging mode of cold energy for one-year operation is studied. The typical meteorological year (TMY) data of Dunhuang, Gansu province, in north-western China, is utilized to determine the lowest ambient temperature and operation time of the system to store cold energy. The proposed seasonal cooling system is capable of enhancing the efficiency of a solar thermal power plant up to 1.54% and 2.74% in comparison with the water-cooled condenser system and air-cooled condenser system respectively. The techno-economic assessment of the proposed technique also supports its integration with the condenser unit in the solar thermal power plant. This technique has also a great potential to save the water in desert areas.

Effect of Storage Temperature on Vitamin C, Total Phenolics,UPLC Phenolic Acid Profile and Antioxidant Capacity of Eleven Potato(Solanum tuberosum) Varieties

Storage of potato tubers at low temperature affects their metabolism and may alter their phytochemical properties. There is a need to elucidate the changes in antioxidant compounds, activity and enzymes during storage of tubers. Eleven Indian potato varieties were evaluated for antioxidant parameters, after 0, 30, 60 and 90 days of storage at room temperature, 15 °C and 4 °C. Total phenolics(0.0786–0.1546 mg gallic acid equivalents·g^(-1)FW) and vitamin C content(0.0828–0.2416 mg·g^(-1)FW) varied among the varieties and were different with storage temperature; their levels fluctuated during storage but remained above the initial level until the last day of observation. Phenolic acid profiling by UPLC identified 12 compounds among which the most abundant was chlorogenic acid followed by gallic acid, sinapic acid and ellagic acid. Except para-coumaric acid which decreased at 4 °C, all the phenolic acids increased with storage. Caffeic acid, chlorogenic acid, protocatechuic acid and gallic acid mostly correlated with total phenolic content(r = 0.456, 0.482, 0.588 and 0.620, respectively). Antioxidant activity against both DPPH and ABTS radicals increased during the initial days of storage and then dropped to a level comparable or lower than the original value,irrespective of the storage temperature. Correlation study revealed that chlorogenic acid, gallic acid and ferulic acid mostly contributed to antioxidant activity. Activity of both antioxidant enzymes, superoxide dismutase and ascorbate peroxidase, increased initially but then decreased to values lower than the initial level and were not influenced by storage temperature. Correlation with antioxidant activity indicated that the enhancement of reactive oxygen scavenging species in cold stored tubers could result mainly from ascorbate peroxidase activity. Our results demonstrate that storage temperature adversely influences the metabolism and the content of antioxidant compounds in potato tubers, with subsequent increase on their antioxidant capacity.

Effects of fluctuating thermal regimes on cold survival and life history traits of the spotted wing Drosophila(Drosophila suzukii)

Drosophila suzukii is an invasive pest causing severe damages to a large panel of cultivated crops.To facili tate its biocontrol with stratcgies such as sterile or incompatible insect techniques,D.suzukid must be mass-produced and then stored and transported under low temperature.Prolonged cold exposure induces chill injuries that can be mitigated if the cold period is interrupted with short warming intervals,referred to as fluctuating thermal regimes(FTR).In this study,we tested how to optimally use FTR to extend the shelf life of D.suzukii under cold storage.Several FTR parameters were asessed:temperature(15,20,25℃),duration(0.5,1,2,3 h),and frequency(every 12,24,36,48 h)of warming intervals,in two wild-type lines and in two developmental stages(pupac and adults).Generally,FTR improved cold storage tolerance with respect to constant low temperatures(CLT).Cold mortality was lower when recovery temperature was 20℃ or higher,when duration was 2 h per day or longer,and when warming interruptions occurred frequently(every 12 or 24 h).Applying an optimized FTR protocol to adults greatly reduced cold mortality over long-term storage(up to 130 d).Consequences of FTR on fitness-related traits were also investigated.For adults,poststorage survival was unaffected by FTR,as was the case for female fecundity and male mating capacity.On the other hand,when cold storage occurred at pupal stage,postorage survival and male mating capacity were altered under CLT,but not under FTR.After storage of pupae,female fecundity was lower under FTR compared to CLT,suggesting an energy trade-off between repair of chill damages and C22 production.This study provides detailed information on the application and optimization of an FTR-based protocol for cold storage of D.suzuki that could be useful for the biocontrol of this pest.

Effect of precooling temperature on physiological quality of cold stored Agaricus bisporus

Effect of precooling temperatures(2℃,6℃,10℃and 14℃)on the physiological quality of postharvest Agaricus bisporus during cold storage was investigated.After six hours’precooling,Agaricus bisporus was stored at 3℃and sampled on day 3,6 and 9,respectively,for physiological quality analysis.Results showed that physiological quality of the Agaricus bisporus increased with the decrease of precooling temperature in the range of 2-14℃.Precooling at 2℃before cold storage had a positive impact on the storage quality of Agaricus bisporus.The decrease of hardness,whiteness and pH value was delayed,while the increase of cell membrane permeability and PPO and POD activities was restrained.Whiteness value of the Agaricus bisporus precooled at 2℃was above 80 on day 9,which means it was still acceptable,but the Agaricus bisporus precooled at 6℃and 10℃lost their commercial values.