Cool Chamber Research Articles

Effect of Modified Atmospheric Packaging on Postharvest Storage Life of Cilantro (Coriandrum sativum L.) Stored Under Different Conditions

Cilantro is a leafy vegetable commonly used for seasoning purpose that is highly perishable and has high postharvest loss losing 1.03 ml water per gram per day. It is therefore an alternative method of storage is needed to extend storage life of Cilantro. So, the research was carried out to study the effect of Modified Atmospheric Packaging (MAP) on postharvest storage life of Cilantro at different storage conditions. The experiment was laid under Completely Randomized Design (CRD) with ten treatments viz. open in tray along with 0, 5, 10 and 15 perforations (having pore size 5 mm) which are stored both in lab and Zero Energy Cool Chamber (ZECC) with three replications of each treatment during March/April (2018) at the Institute of Agriculture and Animal Science (IAAS) Lamjung Campus. Cilantro bought from market was packed in 250 gauge polyethylene bags, each bag was filled with 200 g Cilantro. Physiological loss in weight (PLW), Chlorophyll content, Colour change and Decay are the parameters that were evaluated. Results revealed that with the increase in number of perforation PLW was increased. Cilantro packed in MAP without perforation and stored in ZECC had minimum PLW (0.75%), no decay development as well as minimum loss of chlorophyll (11.18%) in comparison with Cilantro stored in lab at two days after storage. Decay percentage was however higher, greater than 50% at 6 days after storage in ZECC. Polyethylene bags without perforation were observed to be best packaging materials for extending storage life of Cilantro up to 4 days in ZECC followed by 2 days in lab.

Evaluation of temperature and relative humidity on two types of zero energy cool chamber (ZECC) in South Sulawesi, Indonesia

Zero Energy Cool Chamber (ZECC) is a cooling chamber for storing fruits and vegetables from the viewpoints of low cost and energy savings. The aim of the present study is to evaluate temperature and relative humidity (RH) on two types of zero energy cool chamber (ZECC) in South Sulawesi, Indonesia. The first category was placed underground while the second category was on the surface. Then, the performance of the ZECC was measured by calculating temperature and relative humidity. The results show that the ZECC was constructed on the surface produce lower temperature and higher RH compare to ZECC which placed underground. In average, the temperature in the outside (28.0°C) is greater than in inside (26.2°C) of the ZECC. On the other hand, the relative humidity in the outside (72.9%) is less than in inside (87.2%) of the ZECC. It was concluded that the ZECC where was constructed on the surface is more suitable than ZECC in the underground for decreasing temperature and increasing relative humidity.

Leipzig Ice Nucleation chamber Comparison (LINC): intercomparison of four online ice nucleation counters

Abstract. Ice crystal formation in atmospheric clouds has a strong effect on precipitation, cloud lifetime, cloud radiative properties, and thus the global energy budget. Primary ice formation above 235 K is initiated by nucleation on seed aerosol particles called ice-nucleating particles (INPs). Instruments that measure the ice-nucleating potential of aerosol particles in the atmosphere need to be able to accurately quantify ambient INP concentrations. In the last decade several instruments have been developed to investigate the ice-nucleating properties of aerosol particles and to measure ambient INP concentrations. Therefore, there is a need for intercomparisons to ensure instrument differences are not interpreted as scientific findings.In this study, we intercompare the results from parallel measurements using four online ice nucleation chambers. Seven different aerosol types are tested including untreated and acid-treated mineral dusts (microcline, which is a K-feldspar, and kaolinite), as well as birch pollen washing waters. Experiments exploring heterogeneous ice nucleation above and below water saturation are performed to cover the whole range of atmospherically relevant thermodynamic conditions that can be investigated with the intercompared chambers. The Leipzig Aerosol Cloud Interaction Simulator (LACIS) and the Portable Immersion Mode Cooling chAmber coupled to the Portable Ice Nucleation Chamber (PIMCA-PINC) performed measurements in the immersion freezing mode. Additionally, two continuous-flow diffusion chambers (CFDCs) PINC and the Spectrometer for Ice Nuclei (SPIN) are used to perform measurements below and just above water saturation, nominally presenting deposition nucleation and condensation freezing.The results of LACIS and PIMCA-PINC agree well over the whole range of measured frozen fractions (FFs) and temperature. In general PINC and SPIN compare well and the observed differences are explained by the ice crystal growth and different residence times in the chamber. To study the mechanisms responsible for the ice nucleation in the four instruments, the FF (from LACIS and PIMCA-PINC) and the activated fraction, AF (from PINC and SPIN), are compared. Measured FFs are on the order of a factor of 3 higher than AFs, but are not consistent for all aerosol types and temperatures investigated. It is shown that measurements from CFDCs cannot be assumed to produce the same results as those instruments exclusively measuring immersion freezing. Instead, the need to apply a scaling factor to CFDCs operating above water saturation has to be considered to allow comparison with immersion freezing devices. Our results provide further awareness of factors such as the importance of dispersion methods and the quality of particle size selection for intercomparing online INP counters.

Numerical Simulation of the Nanoparticle Diameter Effect on the Thermal Performance of a Nanofluid in a Cooling Chamber

Numerical Simulation of the Nanoparticle Diameter Effect on the Thermal Performance of a Nanofluid in a Cooling Chamber

Comparing contact and immersion freezing from continuous flow diffusion chambers

Abstract. Ice nucleating particles (INPs) in the atmosphere are responsible for glaciating cloud droplets between 237 and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. To date, direct comparisons of contact and immersion freezing with the same INP, for similar residence times and concentrations, are lacking. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data were obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH) using 80 µm diameter droplets, which can interact with INPs for residence times of 2 and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter Arizona Test Dust (ATD) and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm−3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm−3 for AgI. For concentrations < 5000 cm−3, the droplets collect only one particle on average during their time in the chamber. For ATD and kaolinite particles, contact freezing efficiencies at 2 s residence time were smaller than at 4 s, which is in disagreement with a collisional contact freezing process but in accordance with immersion freezing or adhesion freezing. With “adhesion freezing”, we refer to a contact nucleation process that is enhanced compared to immersion freezing due to the position of the INP on the droplet, and we discriminate it from collisional contact freezing, which assumes an enhancement due to the collision of the particle with the droplet. For best comparison with contact freezing results, immersion freezing experiments of the same INPs were performed with the continuous flow diffusion chamber Immersion Mode Cooling chAmber–Zurich Ice Nucleation Chamber (IMCA–ZINC) for a 3 s residence time. In IMCA–ZINC, each INP is activated into a droplet in IMCA and provides its surface for ice nucleation in the ZINC chamber. The comparison of contact and immersion freezing results did not confirm a general enhancement of freezing efficiency for contact compared with immersion freezing experiments. For AgI particles the onset of heterogeneous freezing in CLINCH was even shifted to lower temperatures compared with IMCA–ZINC. For ATD, freezing efficiencies for contact and immersion freezing experiments were similar. For kaolinite particles, contact freezing became detectable at higher temperatures than immersion freezing. Using contact angle information between water and the INP, it is discussed how the position of the INP in or on the droplets may influence its ice nucleation activity.

Immersion mode ice nucleation measurements with the new Portable Immersion Mode Cooling chAmber (PIMCA)

AbstractThe new Portable Immersion Mode Cooling chAmber (PIMCA) has been developed for online immersion freezing of single‐immersed aerosol particles. PIMCA is a vertical extension of the established Portable Ice Nucleation Chamber (PINC). PIMCA immerses aerosol particles into cloud droplets before they enter PINC. Immersion freezing experiments on cloud droplets with a radius of 5–7 μm at a prescribed supercooled temperature (T) and water saturation can be conducted, while other ice nucleation mechanisms (deposition, condensation, and contact mode) are excluded. Validation experiments on reference aerosol (kaolinite, ammonium sulfate, and ammonium nitrate) showed good agreement with theory and literature. The PIMCA‐PINC setup was tested in the field during the Zurich AMBient Immersion freezing Study (ZAMBIS) in spring 2014 in Zurich, Switzerland. Significant concentrations of submicron ambient aerosol triggering immersion freezing at T > 236 K were rare. The mean frozen cloud droplet number concentration was estimated to be 7.22·105 L−1 for T < 238 K and determined from the measured frozen fraction and cloud condensation nuclei (CCN) concentrations predicted for the site at a typical supersaturation of SS = 0.3%. This value should be considered as an upper limit of cloud droplet freezing via immersion and homogeneous freezing processes. The predicted ice nucleating particle (INP) concentration based on measured total aerosol larger than 0.5 μm and the parameterization by DeMott et al. (2010) at T = 238 K is INPD10=54 ± 39 L−1. This is a lower limit as supermicron particles were not sampled with PIMCA‐PINC during ZAMBIS.

Thermal Performance Analysis of Nanofluid Thermal Conductivity Models in a Cooling Chamber

This study focused on the numerical modeling of mixed convection heat transfer in two-dimensional double lid-driven cavity filled with alumina–water nanofluid. Four different thermal conductivity models as well as experimental thermal conductivity data of Das et al. are used to estimate nanofluid thermal conductivity that incorporates the effects of nanoparticles concentration, Brownian motion, temperature, nanoparticle size, and interfacial-layer thickness. These models are used to evaluate the heat transfer enhancement and the increase of the average Nusselt number on a hot wall. The governing stream-vorticity equations are solved using a second-order central finite-difference scheme, coupled to the conservation of mass and energy. The main sensitive parameters of interest selected to investigate the thermal conductivity models are volume fraction of the nanoparticles (), Richardson number , and Reynolds number . The performance study of the thermal conductivity models and the interpretation of the corresponding results of isothermal lines, temperature profile, and average Nusselt number on a hot wall are done in a different range of , Richardson number, and Reynolds number for forced, mixed, and natural convections. As a result, it found that higher heat transfer is produced when the effects of nanoparticle size and interfacial-layer thickness are considered.

Efficacy of evaporative cool chamber in pasighat condition, Arunachal Pradesh, India

Effectiveness of low cost cool chamber-an on-farm rural oriented storage structure which operates on the principle of evaporative cooling developed at IARI, New Delhi was studied under Pasighat condition. Freshly harvested vegetables viz. brinjal, frenchbean, green chillies, coriander and tomatoes were subjected to storage in evaporative cool chamber and ambient condition. The average minimum and maximum temperatures during storage period at cool chamber were 20.4°C and 30.23°C respectively and relative humidity were 74% and 95%, respectively. The minimum and maximum temperatures during storage at room temperature condition were 26.1°C and 31.8°C respectively and relative humidity were 59% and 79% respectively. Results indicate that storage at cool chamber increases the shelf life of all the vegetables by considerably reducing the physiological loss in weight (PLW), retaining sensory quality like colour, texture and increases marketability. Cool chamber was suitable for storing brinjal for 9–15 days, beans and green chillies for 8–10 days, coriander for 3 days and tomatoes for 14–15 days as against 4–5 days for brinjal, beans and green chillies, 1 day for coriander and 7 days for tomatoes in room condition.

Dynamic optimization of inside temperature of Zero Energy Cool Chamber for storing fruits and vegetables using neural networks and genetic algorithms

A ‘Zero Energy Cool Chamber (ZECC)’ has been developed for storing fruits and vegetables from the viewpoints of low cost and energy savings. Adding water to a filler between the outer and inner brick walls and shade curtains is effective way to reduce the inside temperature of a ZECC. The objective of this study was to minimize the inside temperature by controlling the watering using an intelligent optimization technique (IOT) combined with neural networks (NN) and genetic algorithms (GA). The objective function was given by the average value of the inside temperature for one day. For dynamic optimization, the control process (24h) was divided into 8 steps, and the optimal value (8-step ON–OFF intervals) of watering was obtained using NN and GA. In this method, dynamic changes in the inside temperature of the ZECC, as affected by the watering strategy, outside temperature and inside relative humidity conditions, were first identified using NN, and then the optimal value, which minimized the objective function, was determined through simulation of the identified NN model using GA. The average inside temperature for this optimal control was 4°C lower than that for the continuous watering for 24h, and was also 7.5°C lower than that for no watering. The ZECC with the optimal watering strategy extended the shelf-life of tomato from 7 to 16days. Thus, it was concluded that a ZECC optimized by using NN and GA is useful for storing tomato with no electric energy.

Optimization of Watering for Minimizing the Inside Temperature of Zero Energy Cool Chamber for Storing Fruits and Vegetables

Abstract A zero energy cool chamber (ZECC) has been developed for storing fruits and vegetables from the viewpoints of low installation and operating cost. The inside temperature of the ZECC is cooled by adding water to a sand and zeolite based filler between the brick walls based on the principles of a natural evaporative cooling mechanism. The objective of this study was to minimize the inside temperature of the ZECC by controlling watering operation using an intelligent optimization technique combined with neural network and genetic algorithm. The objective function was given by the average value of the inside temperature for one day. For optimization, the control process (24 hours) was divided into 8 steps, and the optimal value (8-step ON-OFF intervals) of watering was obtained using neural networks and genetic algorithms. In this method, dynamic changes in the inside temperature of the ZECC, as affected by the watering strategy and outside temperature, were first identified using neural network, and then the optimal value, which minimized the objective function, was determined through simulation of the identified neural-network model using genetic algorithm. The average inside temperature for this optimal ON-OFF control was 5°C lower than that for the simple ON-OFF watering for 24 hours, and was also 8°C lower than that for no watering. The ZECC with the optimal ON-OFF watering strategy extended the shelf-life of untreated tomato from 7 to 16 days. Thus, it was concluded that a ZECC optimized by using neural networks and genetic algorithms is useful for storing tomato with no electric energy.

Time dependence of immersion freezing: an experimental study on size selected kaolinite particles

Abstract. The time dependence of immersion freezing was studied for temperatures between 236 K and 243 K. Droplets with single immersed, size-selected 400 nm and 800 nm kaolinite particles were produced at 300 K, cooled down to supercooled temperatures, and the fraction of frozen droplets with increasing residence time was detected. To simulate the conditions of immersion freezing in mixed-phase clouds we used the Zurich Ice Nucleation Chamber (ZINC) and its vertical extension, the Immersion Mode Cooling chAmber (IMCA). We observed that the frozen fraction of droplets increased with increasing residence time in the chamber. This suggests that there is a time dependence of immersion freezing and supports the importance of a stochastic component in the ice nucleation process. The rate at which droplets freeze was observed to decrease towards higher temperatures and smaller particle sizes. Comparison of the laboratory data with four different ice nucleation models, three based on classical nucleation theory with different representations of the particle surface properties and one singular, suggest that the classical, stochastic approach combined with a distribution of contact angles is able to reproduce the ice nucleation observed in these experiments most accurately. Using the models to calculate the increase in frozen fraction at typical mixed-phase cloud temperatures over an extended period of time, yields an equivalent effect of −1 K temperature shift for an increase in times scale by one order of magnitude. This suggests that temperature is more important than time.

Storage Behaviour of Guava Fruits in Evaporative Cool Chambers during Winter Season

Shelf life of guava in evaporative cool chamber during winter was evaluated on the basis of physiological loss in mass, acidity, total soluble solids and ascorbic acid. Results indicated that the evaporative cool chambers could be an ideal on-farm storage facility for maintaining quality and overall acceptability of guava. The average difference in dry bulb air temperature between ambient and evaporative cool chamber with river bed sand (ECC RBS) was 8.1 ºC, and between ambient and evaporative cool chamber with rice husk ash (ECC RHA) was 9.0 ºC during storage. Guava fruits stored in cool chamber had double shelf-life as compared to storage under ambient condition, and also had high organoleptic score. The evaporative cool chamber with risk husk ash was found to be more effective in reducing dry bulb temperature, elevation in relative humidity and increase in cooling efficiency than evaporative cool chamber with river bed sand.

A Study on Cost Effective and Eco Friendly Earthen Pot Cool Chamber (EPCC-2) System for Rural Population to Store Post Harvest Vegetables

A Study on Cost Effective and Eco Friendly Earthen Pot Cool Chamber (EPCC-2) System for Rural Population to Store Post Harvest Vegetables

Zero Energy Cool Chamber for Extending the Shelf-Life of Tomato and Eggplant

A zero energy cool chamber (ZECC) consisting of a brick wall cooler and a storage container made of new materials has been developed. The ZECC requires no electric energy. The brick wall cooler made of bricks with a mixture of moistened sand and zeolite allows low inside temperature and high relative humidity to be maintained based on the principles of a natural evaporative cooling mechanism. Several types of storage containers coated with different antibacterial materials were applied to reduce decay. For example, silver-ion-coated storage containers were used to reduce decay. Heat treatment was also applied to the commodities in order to maintain freshness. Generally, tomato and eggplant had a shelf life of 7 and 4 days at room temperature, respectively, as compared to 16 and 9 days when stored in the ZECC. Tomato and eggplant treated with hot water reduced the percentage of rotting. Tomato treated with hot water at 60°C for three minutes and eggplant treated with hot water at 45°C for an hour when stored inside silver-ion-coated containers in the ZECC showed extended shelf life of up to 28 and 15 days, respectively. Discipline: Food Additional key words: inside temperature, postharvest loss, relative humidity, shelf life, storage *Corresponding author: e-mail morimoto@agr.ehime-u.ac.jp Received 5 July 2011; accepted 19 January 2012.

Post-harvest storage of lime fruits (Citrus aurantifolia) following high humidity and low temperature in a modified brick wall cooler.

The use of a modified brick wall Evaporative Cooling Chamber (ECC) for extending the shelf life of limes ( Citrus aurantifolia ) was compared with ambient storage. The shelf life inside of the ECC was extended by five to twenty days relative to ambient storage. The inside temperatures were about 4-6

Comparative Study on Storage of Fruits and Vegetables in Evaporative Cool Chamber and in Ambient

An evaporative cool chamber was constructed with the help of baked bricks and riverbed sand. Maximum and Minimum temperature and relative humidity were recorded inside and outside the chamber for about one month. It was found that inside temperature was about 10-15°C lower than outside temperature and inside humidity was about 30-40 % higher than outside. A comparative study was made for the storage of different fruits and vegetables inside the cool chamber and in the ambient condition and their weight loss and freshness were observed everyday. It has been recorded that weight loss of fruits and vegetables kept inside the chamber was lower than those stored outside the chamber. The fruits and vegetables were fresh up to 3 to 5 days more inside the chamber than outside. The evaporative cool chamber does not require mechanical or electrical energy input and can be constructed with locally available material with unskilled labour. It is economical and can store the fruits and vegetables for 3 to 5 days with no significant loss.

Experimental study of air gap and direct contact membrane distillation configurations: application to geothermal and seawater desalination

The membrane distillation (MD) is a process for vapour extraction from aqueous solution at temperature which my be much lower than the boiling point of the solution. This operation is realized by means of a micro porous hydrophobic membrane separating a warm solution from a cooler chamber which contains either liquid or gas. The membrane distillation has been used to concentrate at high level different kinds of solutions, to remove salt from seawater in semi-industrial applications and to separate alcohol-water solutions in biotechnological systems. Recently, this process has been used in water desalination and wastewater treatment. So far, essentially two different configurations of membrane distillation processes have been used, namely direct contact membrane distillation (DCMD) and air gap membrane distillation (AGMD). Several authors have performed experimental and theoretical analysis of both processes, and desalination equipment based on DCMD and AGMD is commercially available. The large air gap in AGMD allows for the existence of important temperature and partial pressure gradient. This paper objective is to realize DCMD and AGMD experimental tools and to study the effect of the following operating variables: feed concentration, feed flow, feed temperature and the air gap width. The flux up to 3–5 kg/m 2h was achieved and the salt rejection is about 97%. The main advantage of membrane distillation lies in its simplicity and the need for only small temperature differentials. The AGMD configuration is more adapted to desalination of geothermal resources, and the need of energy is lower — only for pumping.

Interdiffusion of H2O and CO2 in metamorphic fluids at ∼490 to 690°C and 1 GPa

Interdiffusion coefficients have been determined for H 2O-CO2 mixtures by quantifying the flux of CO2 between two fluid-filled chambers in a specially designed piston-cylinder cell. The two chambers, which are maintained at 1.0 GPa and at temperatures differing by 100°C, each contain the XCO2-buffering assemblage calcite quartz wollastonite, in H2O. The positive dependence of XCO2 on temperature results in a down-temperature, steady-state flux of CO 2 through a capillary tube that connects the two chambers. This flux drives the wollastonite calcite quartz equilibrium to the right in the cooler chamber, producing a measurable amount of calcite that is directly related to CO2-H2O interdiffusion rates. Diffusivities calculated from seven experiments range from 1.0 10 8 to 6.1 10 8 m 2 /s for mean capillary temperatures between 490 and 690°C. The data set can be approximated by an Arrhenius-type relation: D 4.7 10 -6 exp-4560/T m 2 /s (T in K), which yields values within a factor of 2 of, but slightly lower than, diffusivities estimated by application of the Stokes-Einstein relation. Because rates of H2O and CO2 interdiffusion approach (within 1 to 2 orders of magnitude) rates of heat conduction in rocks, rapid CO2-H2O interdiffusion should be expected in deep-seated fluids wherever gradients in XCO2 are imposed by contrasting mineral assemblages. Considering the small-scale heterogeneity of the crust, strong gradients in XCO2 are probably quite common, particularly where different carbonate- bearing assemblages are juxtaposed or where they are interlayered with carbonate-absent rocks. Cross-layer, diffusive mass transfer of CO2 and H2O may play an important role in driving dehydration and decarbonation reactions, even in the absence of fluid flow. Copyright © 2004 Elsevier Ltd

Influence of Ambient and Evaporative Cool Chamber Storage Conditions on the Quality of Polyethylene-Packed Kinnow Fruit

Influence of Ambient and Evaporative Cool Chamber Storage Conditions on the Quality of Polyethylene-Packed Kinnow Fruit

Study on the Efficiency Improvement of CDQ Waste Heat Recovery System. 1st Report. Dynamic Characteristics of CDQ Cooling Chamber.

CDQ (cokes dry quenching system) is a waste heat recovery system that recovers waste heat from hot cokes with circulating gas and that generates high-pressure steam. In heat recovery systems, it is very important to operate the system with maximum efficiency. In CDQ, the flow rate of circulating gas must be manipulated to obtain maximum flow rate of steam. For this purpose, the dynamic model of this system is necessary. In this system, a temperature distribution within the each coke exists, because the diameter of the coke is relatively large and value of thermal conductivity is small. In this report, we investigated the dynamic characteristics of the system, taking account of the heat conduction effect within the each coke. The validity of this model is confirmed by comparing the calculated result with operation data. Next, we show that dynamic characteristics depend on three nondimensional parameters, namely, Biot number, NTU and Cr number. In the next roport, we will establish the optimum operation method using this model.