Cold Storage System Research Articles

Optimization of a cold thermal energy storage system with micro heat pipe arrays by statistical approach: Taguchi method and response surface method

Optimization of a cold thermal energy storage system with micro heat pipe arrays by statistical approach: Taguchi method and response surface method

Integration of renewable energy-powered cold storage solutions for reducing post-harvest food waste in rural agricultural areas

Post-harvest food loss remains a critical challenge in rural agricultural areas, exacerbated by inadequate storage facilities and unreliable energy access. This study develops and optimizes an advanced renewable energy-powered cold storage system tailored for rural settings, integrating solar and wind energy with phase change materials (PCMs) for efficient energy storage. The system incorporates Internet of Things (IoT)-based sensors and artificial intelligence (AI)-driven energy management to maintain optimal storage conditions and enhance energy efficiency. Field trials conducted in Lincolnshire, UK, and Appalachian regions of the US demonstrated significant reductions in post-harvest food loss by an average of 43.5%, extensions in produce shelf-life by up to 300%, and increased income for smallholder farmers by approximately 43%. The system also achieved an 80% reduction in greenhouse gas emissions compared to conventional diesel-powered systems. Economic analyses revealed a shorter payback period and higher return on investment, confirming the system's viability. High user satisfaction and adoption rates indicate the system's practicality and potential for widespread implementation. The findings suggest that integrating renewable energy with smart technologies in cold storage solutions offers a scalable and sustainable approach to enhancing food security, promoting economic growth in rural areas, and supporting environmental objectives globally.

Photovoltaic-powered seasonal snow storage-assisted district cooling system: Site suitability analysis and performance assessment

District cooling (DC) plants coupled with cold thermal energy storage (TES) and photovoltaic (PV) systems are getting attention worldwide. Utilising winter snow is a successfully implemented TES technology, with little scale-up. Its site identification and cooling potential are not yet fully explored, especially for DC applications. The objective of this paper is to carry out site suitability analysis and performance assessment for PV-powered snow storage-assisted DC system. The site selection methodology is based on multi-criteria decision-making techniques and geographic information system. Performance analysis is carried out mathematically by considering ten indicators. The robustness of the study is enhanced by multiple sensitivity analysis. For the base case scenario, the dominant selection criteria are observed to be cooling load density (30 %), proximity to electric grids (17 %) and air temperature (13 %). Out of the selected land cover (vacant/crops/rangeland) in Estonia, around 34 km2 was observed to be moderately-suitable for the development of the proposed system. For a specific site, the theoretical generation potential of snow cooling facility is estimated as 1728 MWh with an annual cooling share of 80 %. With annual energy output of 1823 MWh and performance-ratio of 78 %, rooftop PV plants is capable to fully power the proposed system. A satisfactory economic and environmental performance is observed at the whole system level. This study is expected to scientifically support the effective utilisation of locally available energy sources (i.e. winter snow and solar energy) for space cooling applications in cold regions.

Simulation of solidification for saving energy with using nanomaterial involving conduction heat transfer

The current article studies the improvement of the discharging rate in cold storage systems by modifying the tank configuration and incorporating additives. Specifically, the study inspects how varying the diameter (dp) and fraction (ϕ) of nano-powders affects the process duration. The governing equations, derived under the assumption of negligible slip velocity of nanoparticles and convection terms, were solved using the Galerkin method. The computational grid was modified owing to location of the ice front, and unsteady terms were discretized using an unconditionally stable approach. The results indicate that initially, increasing dp decreases the process duration by approximately 20.01 %, but further increases in dp lead to a 49.53 % rise in the duration. As the process time increases, the amount of ice produced also increases, with nanoparticle loading resulting in a significantly higher ice yield. Specifically, the incorporation of nanoparticles enhances the storage rate by approximately 41.37 %.

Assessment of cold storage system in existence of nanomaterial using Galerkin technique

Assessment of cold storage system in existence of nanomaterial using Galerkin technique

Comparative Analysis of the Characteristics of Two Hardy Kiwifruit Cultivars (Actinidia arguta cv. Cheongsan and Daebo) Stored at Low Temperatures.

A cold storage system is useful for maintaining the quality of hardy kiwifruit. However, extended cold storage periods inevitably result in cold stress, leading to lower fruit marketability; the severity of chilling injury depends on fruit types and cultivars. In this study, the impact of cold storage conditions on the physicochemical properties and antioxidant capacity of two phenotypically different hardy kiwifruit cultivars-'Cheongsan' (large type) and 'Daebo' (small type)-stored at low (L; 3 °C, relative humidity [RH]; 85-90%) and moderate-low (ML; 5 °C, RH; 85-90%) temperatures was determined. Significant differences in fruit firmness and titratable acidity between treatments L and ML were observed in both cultivars during the experimental storage period. Meanwhile, the browning and pitting rates of the 'Cheongsan' fruits in treatment L increased for 8 weeks compared with those of the 'Daebo' fruits in treatments L and ML; nonetheless, fruit decay was observed in the 'Daebo' fruits in treatment ML after 6 weeks. The total chlorophyll, carotenoid, flavonoid, and ascorbic acid concentrations as well as the antioxidant activities of both the cultivars significantly differed between treatments L and ML. After 2 weeks of storage, the 'Cheongsan' fruits in treatment L had lower antioxidant activities and ascorbic acid content than those in treatment ML. These results demonstrate that the quality attributes and antioxidant activity of hardy kiwifruit are influenced by the low-temperature storage conditions and the specific kiwifruit cultivars. Our findings suggest that optimal cold storage conditions, specific to each hardy kiwifruit cultivar, promise to maintain fruit quality, including their health-promoting compounds, during long-term storage.

Implementation of nanoparticles for expedition of freezing through storage unit involving conduction mechanism

This work employs an approach to examine the effects of adding alumina nanoparticles with varying diameters (dp) to water on the productivity of cold storage. Utilizing a finned geometry with a curved cold wall, the mesh configuration was adapted to the solid front's location, and unsteady terms were discretized using implicit methods. The concentration (ϕ) of alumina nanoparticles was also evaluated as a key parameter. Results indicated that increasing the concentration of nanoparticles improved cold storage efficiency by approximately 42.11 %. Among the various sizes, medium-sized nanoparticles were most effective, yielding a 20 % improvement in freezing efficiency compared to the smallest size. Optimal nanoparticle dispersion significantly reduced the required cooling time from 9383.58 s to 5507.129 s. This study highlights the substantial benefits of combining fins and nanoparticles to enhance cold storage systems, presenting a notable advancement in thermal management technology.

Analyzing porous cold storage unit in presence of hybrid nano-powders considering Galerkin method

The article presents a comprehensive simulation study on cold storage porous containers, employing the Galerkin method to analyze their thermal behavior. A key focus of the investigation is the incorporation of both radiation and conduction modes within the mathematical model, acknowledging their significant roles in the freezing process. To enhance the freezing rate, hybrid nanoparticles are introduced into H2O, aiming to speed up the solidification. Notably, the study integrates adaptive grid techniques to achieve higher modeling accuracy, with verification processes confirming a high level of agreement between simulation results and experimental data. This research also underscores the potential for improved energy efficiency in cold storage systems, contributing to the sustainability of natural resources by reducing energy consumption and enhancing the overall efficiency of thermal storage systems. Through meticulous examination, the study explores the impacts of various factors on freezing, including the fraction of hybrid nano-powders (ϕ), porosity (γ), and the radiation factor (Rd). Remarkably, the introduction of porous media causes to a substantial increment in the freezing rate, resulting in an improvement of approximately 91.19 %. Moreover, the inclusion of the radiation term in the model significantly reduces the completion time by approximately 30.85 %, underscoring the importance of considering radiation effects in such systems. Additionally, dispersing hybrid nano-powders into the water, results in a decrement in the freezing time around 7.21 %. This approach highlights the significant potential for optimizing energy use in thermal storage applications, thereby promoting the conservation and sustainable management of natural resources.

On the role of building use and operational strategy in integrating ice storage systems: an economic perspective

Ice thermal energy storage has been widely used in different types of building to manage cooling peak loads. In the present study, technical and economic feasibility studies have been performed to evaluate the effect of building use and storage strategy on integrating ice storage. Four different building uses, namely residential, office, educational, and commercial; and nine storage strategies are investigated. For each building type and storage strategy, the hourly cooling load is simulated for a typical day in each month. The appropriate cooling system is then selected and analyzed in terms of energy consumption. The additional capital required to install ice storage and the potential savings obtained by shifting the cooling load from peak to off-peak hours using this installation are estimated to assess the economic feasibility of integrating the storage system. The results show that although the energy consumption in systems with ice storage is generally higher than that in a conventional system, the annual energy costs can be up to about 50 % lower with appropriate storage strategies, albeit at the expense of a higher initial investment. It is also shown that building use and storage strategy significantly impact the economic feasibility of integrating ice storage into building cooling systems. Comparing four building types, the use of an ice storage system in residential buildings is much less economical due to the presence of 24-h cooling loads, so the payback period assuming an electricity tariff of 20¢ and considering the best storage strategy is more than 7 years, which is 62, 66 and 73 months more than the payback period for the office, commercial and educational buildings, respectively. Therefore, implementing different policies for residential and non-residential buildings is recommended to encourage the use of cold storage systems in the building sector.

TOWARDS CARBON-NEUTRAL FISH COLD STORAGE: A SUSTAINABLE APPROACH THROUGH RENEWABLE ENERGY

Preserving perishable foods, particularly fish, demands meticulous attention throughout the entire supply chain, from capture to consumption. The critical role of cold storage facilities in maintaining optimal conditions, encompassing temperature and humidity regulation, is indispensable. Nevertheless, these facilities pose a considerable challenge due to their substantial electrical energy consumption, which significantly contributes to operational costs. In addressing this challenge, the implementation of energy-efficient strategies, including the utilization of advanced equipment and real-time monitoring facilitated by automation technologies, becomes imperative. This research investigates an innovative integrated cold storage system situated in Tarrafal, Santiago, Cape Verde, which harmoniously incorporates wind, solar, and tidal energy sources. The primary objectives are to evaluate the energy efficiency, financial viability, and environmental impact across four distinct hypothesis. Hypothesis 1 entails the deployment of two R134a refrigeration units powered by the conventional public grid, while Hypothesis 2 adopts a transcritical CO2 system reliant on grid electricity, Hypothesis 3 integrates CO2 technology with autonomous renewable energy sources and Hypothesis 4 leverages CO2 for refrigeration coupled with seawater heat exchange and autonomous renewable energy generation. The research findings strongly favor Hypothesis 4, demonstrating emissions of 15880 kg CO2eq with an impressive 5-year return on investment. The autonomous electricity production associated with this hypothesis markedly reduces emissions by more than 90%. Despite an initial higher investment, Hypothesis 3 showcases financial viability, contributing significantly to long-term energy sustainability. The autonomous energy production in this scenario results in a noteworthy reduction of more than 600000 kgCO2 compared to conventional systems, underscoring the positive impact of integrating local renewable energy sources.

Experimental study on improving the thermal performance of isobutane refrigeration system by parameter optimization

Improvement of thermal efficiency for isobutane refrigeration system could match well with the building requirements of low-carbon, and sustainable development. The electric radiant heater (ERH) is widely used for the freeze and cold storage (FCS) system, but it has problems of high electric consumption and high freezer compartment temperature rise (FCTR) as a result of low heat-transfer efficiency under defrosting. Therefore, a novel FCS system with an additional electric radiant heater (AERH) based on the heat required for frost melted and synchronous defrosting is proposed. The defrosting consumption and the FCTR of the novel FCS system are comprehensively evaluated by a novel evaluation method. Besides, the effect of the thermal parameters (i.e., the defrosting pause temperature, the position, and electric power of the AERH) on the heat transfer characteristics are compared and optimized by the experimental method. Finally, a novel method is presented to predict the optimum thermal conditions. The results show that the optimum system thermal performance is obtained, the defrosting duration and defrosting consumption are reduced by 44.02 % and 37.03 %, and the defrosting efficiency and energy efficiency could be increased by 17.92 % and 9.96 %, respectively, as compared to the conventional FCS system. The proposed FCS system has better economic performance and heat transfer efficiency. Meanwhile, 30.54 kg of CO2 emissions could be avoided during the annual operation period, and the environmental benefits are also considerable. This study not only reaffirms the benefit of using the AERH for defrosting in the FCS system but also provides a reference for the promotion and application of efficient heat transfer technology in building refrigeration engineering.

Evaluation of thermal storage system during freezing and loading nano-powders

In pursuit of advancing the efficiency of cold energy storage, a uniquely designed curved container has been employed, filled with a water-nanoparticle mixtureQ. The container is equipped with fins, strategically leveraging the enhanced conduction facilitated by the presence of nanoparticles. The simulation of the intricate unsteady phenomena in this study has been conducted using the finite element technique, providing a robust analytical framework. The incorporation of an adaptive grid ensures a refined resolution, particularly in the vicinity of the ice front region. The nanoparticle fraction (ϕ) emerges as a pivotal factor directly influencing the rate of solidifying. The dispersion of nano-powders leads to a noteworthy reduction in completion time, demonstrating a substantial 33.21% improvement. The diameter of the nano-powders (dp) introduces diverse effects on the solidification process, primarily due to its significant influence on the conductivity of the nanomaterial. An in-depth exploration of the impact of dp reveals compelling insights. As the dp increases from its smallest size to 40 nm, there is a commendable 15.12% reduction in the required freezing time. However, a subsequent increment in dp beyond this threshold results in a notable 36.56% increase in the freezing time. The findings presented here not only contribute to the fundamental understanding of freezing processes but also hold practical implications for the design and optimization of cold storage systems.

The effect of anti-agglomerant tween on the thermal and rheological properties of TBAF semi-clathrate hydrate slurry used for cold storage systems

Hydrate, as a phase change cold storage material, can form the slurry with certain fluidity, enabling convective heat transfer during both the heat absorption and heat release stages (cold storage or refrigeration), with high heat transfer efficiency. However, high viscosity and significant flow pressure losses are the principal challenges limiting its advancement. The paper selected four non-ionic surfactants as hydrate anti-agglomerants (Tween 20, 40, 60, 80) and utilized DSC to examine their effects on the thermal properties of TBAF semi-clathrate hydrate slurry at three theoretical hydrate concentrations (with mass fraction of 0.60, 0.70, and 0.80). Additionally, it measured the viscosity variation during the endothermic dissociation stage of the TBAF hydrate slurry and calculated the flow pressure losses in hydrate slurries within various pipe diameters. The results revealed that the presence of Tween increased the hydrate growth within the slurry, resulting in a higher available phase change enthalpy. Tween 80 demonstrated the most significant increase in enthalpy increasing effect, with an available phase change enthalpy ranging from 128.08 to 170.03 kJ/(kg·slurry) and an increase in enthalpy of 52.14 % to 91.62 %. For TBAF hydrate slurries with the theoretical hydrate mass fraction of 0.60, the addition of Tween 20 or Tween 80 significantly reduced viscosity, dropping to between 57.6 mPa·s and 116 mPa·s, and reducing viscosity by 43.4 % to 71.9 %. Furthermore, most flows with anti-agglomerants were in the laminar regime. The addition of Tween 20 and Tween 80 achieved the maximum reduction in flow pressure loss per unit length, with the highest reduction being 80.2 % (0.11 kPa/m) and 71.1 % (0.15 kPa/m), respectively. Both the phase change enthalpy of the hydrate and the viscosity of the hydrate slurry impacted the flow pressure drop within pipes. Increasing phase change enthalpy and reducing viscosity are effective strategies for mitigating flow pressure drop.

Sustainable CO2 Refrigeration System for Fish Cold Storage Facility Using a Renewable Integrated System with Solar, Wind and Tidal Energy for Cape Verde—Analyzing Scenarios

This study compares four feasible alternative solutions for an integrated cold storage system in the city of Tarrafal, Santiago, Cape Verde. Integrated systems using grid electricity are compared with autonomous systems generating electrical energy from renewable sources, alongside various types of refrigeration facility systems. Its objective is to assess the energy efficiency, financial feasibility, and environmental impact across four scenarios. Scenario 1 utilizes two R134a refrigeration units powered by the public grid. Scenario 2 employs a transcritical R744 (CO2) system using grid electricity. Scenario 3 incorporates R744 and autonomous renewable energy. Scenario 4 employs R744 for refrigeration with seawater heat exchange and autonomous renewable energy sources. The findings favor Scenario 4, emitting 15,882 kg CO2 eq with a 5-year return on investment. Autonomous electricity production in this scenario reduces emissions by 95%. Despite an initial cost of EUR 769,172.00, Scenario 3 demonstrates financial viability, contributing to energy sustainability. This autonomous production reduces emissions by 360,697 kg CO2 compared to conventional systems, highlighting the positive impact of local renewable energy integration.

Preparation and properties of gel-type low-temperature phase change materials

In the context of the dual‑carbon target, there is a high emphasis on the energy efficiency of traditional mechanical cold storage systems with significant power consumption. Additionally, the implementation of time-of-use electricity pricing has played a crucial role in driving the rapid advancement of energy storage technology. The application of energy storage technology in cold storage can significantly reduce the energy consumption of the refrigeration system, save operating costs by shifting peak demand to valleys, and reduce start and stop frequencies. Therefore, studying phase-change materials with high latent heat, low cost, and good performance for cold storage is of great practical application in cold storage. The paper developed four types of gel-type phase-change cold storage materials with high latent heat, low cost, and good cycle stability. These materials mainly consist of NH4Cl, KCl, and deionized water. The phase transition temperature ranges from −18 to −21 °C, the latent heat of phase change is approximately 260 to 289 J/g, and the thermal conductivity ranges from 0.58 to 0.60 W/(m·K), which can meet the cooling demand of cold storage facilities. Furthermore, by comparing the phase transition temperature, latent heat value of phase change, and cyclic stability, a gel-type PCM with good comprehensive properties was selected for corrosion and corrosion inhibition studies with five common metal samples in welded and non-welded forms. The results showed that material B2 had slight corrosion on 1060 aluminum, 6061 aluminum, and 304 stainless steels, but no obvious corrosion phenomenon was found on 316 stainless steels. The corrosion rate of the material on red copper was the highest, and the corrosion was too strong. In addition, the corrosion of welded parts is more serious than that of non-welded parts, and the welding points are more susceptible to corrosion. Adding the corrosion inhibitor BTA to material B2 can reduce the corrosion rate of red copper by more than 94 %.

Experimental study of the effect of dedicated mechanical subcooling on the performance of a single multiparallel evaporator

In systems with a single machine and multiple parallel evaporators, issues such as uneven liquid–vapor phase refrigerant separation and low efficiency are prevalent. This study investigates the impact of distributor inlet conditions on liquid–vapor separation uniformity and proposes improving separation performance and system efficiency by adjusting the working fluid's dryness through subcooling. It introduces the use of a rectifying nozzle-type distributor (RD) instead of a centrifugal distributor (CD) and presents experimental studies on multiple parallel evaporators. A test setup featuring multiple parallel evaporators with mechanical subcooling unit was developed to investigate the subcooling degree's impact on various aspects: superheat unevenness across branches, refrigeration capacity disparity among cold storages, cooling rates, distributor pressure drop, and overall system energy efficiency. Findings indicate significant improvements with RD; at a 16 °C subcooling degree, superheat unevenness and refrigeration capacity unevenness decreased by 30.6 % and 23.0 % respectively, while cooling rates increased by 27.3 %. At a 26 °C subcooling degree, system energy efficiency improved by 15.4 %. Compared under identical conditions, the RD system outperformed the CD system. This research contributes to a better understanding of optimizing multiple parallel evaporator performance through subcooling degree adjustments and can be applied to multi-cold room cold storage systems.

Design and analysis of a 20-feet modular cold storage system

Cold storage plays an essential role in the cold supply chain, especially for fishery products. Compact cold storage systems that can be easily moved across various locations are attractive for archipelagic regions. This study aims to design and analyze a 20-ft modular cold storage system. The design stages include the development of a geometrical model, calculation of cooling load, and selection of a refrigeration machine. The analysis of the designed cold storage system was performed using transient computational fluid dynamic simulations using Ansys Fluent. The compact 20-ft cold storage design consists of three main rooms: the anteroom, air blast freezer room, and freezer storage room. The calculation results showed a maximum cooling load of about 6.6 kW occurring in the air blast freezer room at noon. According to the temperature distribution from the transient computational fluid dynamic simulation, each room had different cooling characteristics, with the highest cooling rate of 94.59 W/h in the air blast freezer room, achieving a targeted temperature of −40 °C in 5 h.

Research on the Cold Storage Characteristics of Ice Storage Photovoltaic Cold Storage

The ice-on-coil storage tank is one of the core devices in the latent heat cold storage system. The main objective of this study is to couple the solar photovoltaic cold storage with Cold Thermal Energy Storage technology. The internal ice-melting coil energy storage system used the water as a heat transfer fluid for adopting a day and night cold storage control strategy. The experiments were conducted for several days under the conditions of photovoltaic-driven cold storage with and without load for a continuous cold storage. The reasons for the occurrence of ice layers during ice accumulation and melting, as well as the operational economy of the system were analyzed. Moreover, the characteristics of the cold storage tank were summarized. Consequently, when the external ice thickness of the coil was within the range of 27 to 32mm, the ice storage rate reached 35.82% and achieved the optimal refrigeration efficiency in both the coil and the cold storage. The daily ice production in the cold storage tank decreased by an average of 22.06% during continuous operation with load compared to the unloaded operation. However, the daily refrigeration capacity increased by 45.774%. In addition, when cold thermal energy storage was coupled with solar photovoltaic technology, the refrigeration capacity decreased by 7.15% compared to using Cold Thermal Energy Storage technology alone, which resulting in an annual electricity cost saving of 30.20%.

Predicting Shelf-Life of Fruits: A Multifactorial Approach using Intrinsic and Extrinsic Determinants

Abstract: Predicting the shelf life of fruits is crucial for maintaining food freshness and reducing waste in the supply chain. This paper presents a novel approach to predicting fruit shelf life using a combination of fruit characteristics and environmental factors. Firstly, the freshness of fruits is assessed based on their physical attributes such as size, shape, and color. Next, a predictive model is developed to estimate the number of days a fruit remains edible in a given cold storage system, considering temperature variations. The proposed method leverages machine learning techniques to analyze historical data and identify patterns that influence fruit degradation over time. Experimental results demonstrate the effectiveness of the proposed approach in accurately predicting fruit shelf life, thus facilitating better inventory management and reducing food wastage. This research contributes to the optimization of fruit storage practices, ultimately leading to improved food quality and sustainability in the agricultural sector

Thermodynamic analysis of La and Mm based metal hydride pairs for solar energy-driven cold storage applications

Cold storage plays a vital role in many applications such as agricultural and food processing units. Metal hydride-based sorption cold storage systems are environmentally friendly as they use hydrogen. In the present study, La and Mm metal hydrides based cooling system is proposed for cold storage application which can work using solar energy. Ten metal hydride (AB5) pairs were selected for the thermodynamic analysis of the cold storage module. The minimum cooling temperature and maximum heat source temperature required for each pair are calculated. Hydrogen storage and thermodynamic properties of La0.95Ce0.05Ni5, La0.85Ce0.15Ni5, and MmNi4.5Al0.5 are obtained by measuring pressure concentration isotherms at different temperatures. The effect of source temperature and cooling temperature on COP, Exergy COP, and specific cooling load (SCL) are studied. MmNi4.6Fe0.4/MmNi4.6Al0.4 pair has attained a theoretical maximum COP and exergy COP of 0.784 and 0.89 respectively at a heat source temperature of 60 °C and cooling temperature of 2 °C. However, at higher heat source temperature La0.95Ce0.05Ni5/MmNi4.5Fe0.5 has better performance than MmNi4.6Fe0.4/MmNi4.6Al0.4. In addition, the effect of cooling load on the size of the system for cold storage of 10 kg apples is also studied. For cold storage of 10 kg apples at 2 ℃, La0.95Ce0.05Ni5/ LaNi4.7Al0.3 has the best performance with a COP of 0.693 and minimum total weight of 18.35 kg.