Portable Refrigerator Research Articles

Efficient portable thermoelectric refrigerator developed with a temperature control system mode at best COP for different seasons and conditions of the year

ABSTRACT Global energy scarcity and pollution resulting from excessive energy consumption are among the most important causes of global warming, in addition to using Freon, which poses a danger to the environment. This led to searching for sustainable alternatives that use less energy to alleviate environmental difficulties and are eco-friendly. The portable thermoelectric refrigerator was developed to control the temperature required in different seasons of the year, for those who live in rural areas in Egypt (such as deserts). The main control unit has five modes (Economic, Minimum, Medium, Fast and Fast not Economic) based on the best coefficient of performance (COP) and minimum energy. The results showed the highest COP, for the economic mode with an 8°C difference in temperature, and the lowest COP with a 26.4°C difference in temperature for the fast not economic mode. On the other hand, the difference temperatures of 12.5°C,18.2°C and 23°C of the mode minimum, medium and, fast, respectively.

Analysis and optimization of effect factors of refrigeration performance of portable micro-refrigerator

The objective of this study was to ascertain an efficient portable cold container, considering the constrained space, low airflow velocity, and uneven heat distribution of a micro-refrigerator, which lead to in insufficient heat dissipation and low refrigeration efficiency. A thermoelectric micro-refrigerator model with a volume of 9083.8 cm3 was established under forced convection heat transfer conditions. Through single-factor and response surface experiments, the impact of thermoelectric elements configuration on refrigeration efficiency was identified. These elements include the input current of the Thermo Electric Cooler (TEC), the derating factor (actual power) of the cooling fan, and the height of the heat sink fin.The results indicate that optimizing the refrigeration conditions significantly enhances the refrigeration efficiency of the micro-refrigerator. At an ambient temperature of 25℃, with a fan derating factor of 0.77 (corresponding to an actual power of 0.8218 W), a heat sink fin height of 59.15 mm, and a TEC input current of 5.09A, under stable conditions,the cold side temperature can reach −11.3 ℃. The hot side temperature is 38.2 ℃, consistent with the response surface experiment result. Numerical simulation under these conditions reveals a cold side temperature of −12.4 ℃ and a hot side temperature of 41.9 ℃, showing a 9.7 % difference from the experimental results. The simulation data further demonstrate that the vertical arrangement of the cooling fan and heat sink can achieve a cold side temperature of −12.9 ℃, effectively maintaining the hot side temperature below 40 ℃. The thermoelectric system investigated in this paper holds promising potential for applications in portable fresh-keeping and refrigeration.

REFRIGERADOR PORTÁTIL ALIMENTADO POR ENERGIA RENOVÁVEL

This study is about the design of a portable refrigerator powered by renewable energy. Research is done on small scale solar and wind energy availability. The refrigeration is generated by thermoelectric modules, also known as Peltier modules. A successful refrigeration project begins with the correct calculation of the heating load. These calculations are based on local data from the intended area of operation (Tramandaí). The Peltier module selection is done through a heat transfer analysis based on the heat sinks used on the design and using the datasheet provided by the module manufacturer. The software EnergyPlus is used to calculate the available power provided by the photovoltaic panel during operation. Finally a brief study about the system electric components is done and its connections are represented in a simplified drawing. The design of the portable refrigerator has some physical and energetic constraints, like the large size and weight of its components, great energy consume by the Peltier modules and the low rate of energy powered by the renewable sources, adding a limitation to the heating. However, when the product is placed at 5 °C in the refrigerator, the temperature is preserved, and the refrigerator works within its limitations energy.

Emvolio - A battery operated portable refrigerator preserves biochemical and haematological integrity of biological samples in preclinical studies.

Background: Emvolio is a non-medical device, indigenously developed portable refrigeration for maintaining the internal temperature 2-8˚C. The Indian Patent Office has granted patent for applications such as preservation and transport of medicines, vaccines, food, beverages, dairy etc. Further, use of Emvolio can be utilized in transport and store biologicals to preserve their biochemical and cellular integrity. The objective of this study was to evaluate the biochemical and haematological integrity of biological samples such as rat blood, serum and liver. Methods: The steady temperature was maintained inside the Emvolio, and it was compared to that of thermocol and polypropylene boxes aided with frozen gel packs. The blood and liver samples were isolated from Wistar rats and kept in Emvolio, thermocol and polypropylene boxes for 10 hrs, and the temperature was monitored. The blood parameters, namely red blood cells (RBC), white blood cells (WBC), platelets, haematocrit, haemoglobin, mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC) and red cell distribution width (RDW), serum parameters like alanine transaminase, alkaline phosphatase, total protein, albumin, creatine kinase, blood urea nitrogen and liver parameters like superoxide dismutase (SOD), glutathione (GSH), catalase were estimated and compared. Results: Emvolio maintained a constant inner temperature range of 2-8˚C, whereas a significant temperature variation was seen in thermocol and polypropylene boxes. There was no significant deviation in the parameters tested when samples were kept in Emvolio for six hours compared to the zero hour readings. In contrast, there was a significant deviation among the parameters for the samples kept in thermocol and polypropylene boxes for six hours compared to zero hour parameters. Conclusions: Emvolio maintained constant temperature and preserved the biological integrity of rat blood, serum and liver. Thus, Emvolio can be efficiently used as a biological sample carrier, especially in preclinical studies.

Design and Fabrication of Solar-Powered Portable Thermoelectric Refrigeration System for Thermolabile Pharmaceuticals

Abstract: In order to maintain the therapeutic efficacy of thermolabile medicine and vaccines, electrical energy must be continuously supplied. For remote areas lacking access to electrical electricity, this poses a serious dilemma. The potency level of thermolabile medications and vaccines is decreased, particularly during last-mile delivery, which causes significant financial loss. In this study, we designed and developed a portable active refrigeration system that runs on solar photovoltaic cells for the refrigeration of thermolabile pharmaceuticals to be utilized in rural areas without access to electricity, especially to facilitate last-mile vaccination delivery. The system makes use of a thermoelectric refrigeration system that, when given electrical power, causes a temperature difference based on the Peltier effect. It will be demonstrated that a solar panel with a peak power of roughly 50W and batteries with a storage capacity of 10Ah are needed for a typical application for vaccine refrigeration. The developed refrigeration system has a 3-liter volume capacity and can store 150 vaccine ampules, each with a 10ml capacity, at temperatures between 2°C to 8°C using a Peltier cell (TEC), that consumes 66 W at 12V

Development of bacterial inactivation model and evaluation of shelf life extension of Littopenaeus vannamei using blue LED illumination

AbstractPacific white shrimps pre‐inoculated with bacterial culture were subjected to blue LED illumination at 4°C and 15°C. Mathematical modeling of bacterial inactivation from 0 to 48 h of illumination revealed that Hom and Weibull model represent the best fit. Shelf life analysis of shrimps illuminated with 1075.68 J/cm2 (I1), 2151.36 J/cm2 (I2), 3227.04 J/cm2 (I3), 4302.72 J/cm2 (I4) dosages at 4°C revealed that reduced counts for pH, trimethylamine, hypoxanthine, total plate count, psychrotrophic bacterial count and weight loss % were observed in I4 samples, whereas TBARS, color and texture were retained better in I1 and I2 samples. Bioelectrical impedance analysis (BIA) revealed that lower internal component change percentage of 7.35 and 14.85 was observed in I1 and I2 samples. Microscopic examination of shrimp muscle disclosed increased disintegration of myofibrillar structures in I4 and I3 samples. Illumination dosage ≤2200 J/cm2 extended the shrimp shelf life to 45 days at 4°C and 15 days at 15°C without changing the quality.Practical ApplicationThe demand for quality seafood products and concern for the safety aspects leads to the development of innovative preservation method. The impact of blue LED illumination on L. vannamei shrimps depicted significant increase shelf‐life and retention of quality parameters. Inactivation kinetics of LED illumination on shrimps depicted that Weibull and HOM model resulted best fit based on the R2 and AIC values helps in process scale‐up and operation at industrial level. Successful implementation of these illumination system as a processing equipment or in cold supply chain transport vessels will help the exporters to reduce the losses and conventional processing cost. It can also be employed in portable refrigerators, freezer boxes, storage shelves and ware houses with slight modifications in designs aspects to extend the shelflife of the seafood without losing its organoleptic properties. Further, it aids in effective export performance and extended distribution of shrimps in domestic market.

Fabrication of a portable refrigerator using thermoelectric Peltier module

Refrigeration expending thermoelectric cooling methods have been in research for the past few decades due to its recompenses paralleled to a vapor-compression refrigerators its lack of moving parts or circulating fluid, invulnerability to leaks, small size, and flexible shape. Likewise, portable refrigerators filled with refrigerants are a big hassle to carry around along with being dangerous. This portable mini refrigerator will be capable of cooling a soft-drink canister or multiple 200 ml bottles at its prototype size and based on the results, something finer can be constructed. This attempt of us at fabricating aneco-friendly refrigerator without having to deal with the prospects of handling a dangerous refrigerant is quite affordable when mass-produced and can be installed in glove compartments of a car or a separate refrigeration compartment can be installed in a vehicle. Furthermore, these can be put into use in organizations by individuals as often as possible.

Performance Study of Portable Semiconductor Refrigeration Device Based on CFD Simulation.

Since the summer of 2022, the whole world has suffered the abnormal weather phenomena of high ambient temperature. Equipment for refrigeration, particularly portable refrigeration equipment, is crucial for personal protection in high-temperature environments, but cooling performance and miniaturization have been challenging issues. A portable air conditioner based on a semiconductor refrigeration device for human body cooling was developed. The total weight of the device is 450 g. The overall power consumption of the device is 82 W and the energy consumption ratio of semiconductor cooling plate is 0.85. The semiconductor refrigeration technology is based on the Peltier effect, supplemented by a DC fan to send the cooling air out to a specified position or zone. The structural parts are manufactured by 3D printing technology to make the overall size of the device more compact. The air volume and cooling performance of the device were analyzed by computational fluid dynamics simulation and the temperature distribution was measured by an infrared thermal imager and other instruments, and the measured results agreed with the CFD simulation results. The test ambient temperature was 20 °C. The measurement results showed that the wind speed of the hot air outlet was 6.92 m/s and that of the cold air outlet was 8.24 m/s. The cold air surface temperature reached a stable state of 13.9 °C in about 4 min, while the hot air surface temperature reached a stable state of 47.2 °C.

Emvolio - A battery operated portable refrigerator preserves biochemical and haematological integrity of biological samples in preclinical studies

Background: Emvolio is a non-medical device, indigenously developed portable refrigeration for maintaining the internal temperature 2–8˚C. The Indian Patent Office has granted patent for applications such as preservation and transport of medicines, vaccines, food, beverages, dairy etc. Further, use of Emvolio can be utilized in transport and store biologicals to preserve their biochemical and cellular integrity. The objective of this study was to evaluate the biochemical and haematological integrity of biological samples such as rat blood, serum and liver. Methods: The steady temperature was maintained inside the Emvolio, and it was compared to that of thermocol and polypropylene boxes aided with frozen gel packs. The blood and liver samples were isolated from Wistar rats and kept in Emvolio, thermocol and polypropylene boxes for 10 hrs, and the temperature was monitored. The blood parameters, namely red blood cells (RBC), white blood cells (WBC), platelets, haematocrit, haemoglobin, mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC) and red cell distribution width (RDW), serum parameters like alanine transaminase, alkaline phosphatase, total protein, albumin, creatine kinase, blood urea nitrogen and liver parameters like superoxide dismutase (SOD), glutathione (GSH), catalase were estimated and compared. Results: Emvolio maintained a constant inner temperature range of 2–8˚C, whereas a significant temperature variation was seen in thermocol and polypropylene boxes. There was no significant deviation in the parameters tested when samples were kept in Emvolio for six hours compared to the zero hour readings. In contrast, there was a significant deviation among the parameters for the samples kept in thermocol and polypropylene boxes for six hours compared to zero hour parameters. Conclusions: Emvolio maintained constant temperature and preserved the biological integrity of rat blood, serum and liver. Thus, Emvolio can be efficiently used as a biological sample carrier, especially in preclinical studies.

Towards techno-economics of green hydrogen as a primary combustion fuel for recreational vehicle vapor absorption refrigeration system

The drive towards the integration of hydrogen in the global primary energy mix to achieve a carbon–neutral and sustainable society requires both minor and major technological modifications in current energy systems. In this study, the viability of green hydrogen as a combustion fuel and its economics have been investigated for an absorption–desorption-based cooling system. Specially designed burners have been retrofitted with the portable ammonia-water-based cooling system (cooling area: 1.4 ft3). Furthermore, the effect of hydrogen flow and the distance from the burner has been investigated and optimized. The system has been compared with both electrical resistive heating using a 12 V DC power supply and propane gas. An increase in hydrogen flow rate leads to high cooling rates. Furthermore, the reduction in the distance between flame and heating surface improves the heat transfer rate. The system running on hydrogen exhibited highest performance compared to both electricity and propane at optimum flow rate and distance. The optimum flow rate and distance was observed to be 29.2l/h and 2 cm respectively. System running on optimum hydrogen conditions consumed 77.37Wh energy with is 9.10% less compared system running on electric resistance heating and 29% less compared to system running on propane. In terms of carbon–neutral economics, 1 kg of hydrogen can potentially replace 3.28 kg of propane (costing around 3.60 to 4.30 USD). Whereas, 8–9 kg of CO2 reduction can be achieved per kg of hydrogen being used. The 3.30 to 4.30 USD/kg may be considered a competitive cost of green hydrogen in comparison to propane as a combustion fuel for the portable refrigeration sector. These results are the first time, highlighting the efficient use of hydrogen in space cooling.

Effect of using hybrid nanofluids as a coolant on the thermal performance of portable thermoelectric refrigerators

This study investigated the effect of using hybrid nanofluids as a refrigerant in portable thermoelectric refrigerator applications on thermal performance. For this purpose, a cooling cabinet with an internal volume of 36 L was designed and produced. Then, the Peltier assembly, with a water-cooled block attached to its hot surface, was placed in this cooling cabinet from the middle of its front cover. With the help of a refrigerant, the heat was removed from the Peltier’s hot surface and transferred to the atmosphere via a water-to-air heat exchanger. Hybrid nanofluids prepared with Al2O3-TiO2-SiO2 and nanoparticles and water were used as the refrigerant in the system. To evaluate the thermal performances of these hybrid nanofluids, the tests were repeated using water without added nanoparticles as the reference case. According to the results obtained from the experimental study, it was observed that in all cases, tests using nanofluids gave better results than the reference cases. In addition, it was determined that the efficiency obtained from the system increased as the nanoparticle ratio in the mixture increased in all cases. Despite significant improvements in cooling cabinet and cooled product temperatures in hybrid nanofluids, the COP values ​​of the systems are slightly lower than in the reference case due to the Peltier effect. Considering the difference between the first and last temperatures of the cooled cabinet, the greatest improvement compared to the reference situation was determined as 30.3 % in the case of loaded state conditions and in the case of using 2 % Al2O3-TiO2-SiO2-Water nanofluid. For the unloaded conditions, this value was obtained as 25.1 % in the case of using 2 % Al2O3-TiO2-SiO2-Water nanofluid. On the other hand, for the unloaded condition, the lowest COP value was calculated as 0.47 and 0.45 when Al2O3-TiO2-SiO2-Water nanofluid was used in 1 % and 2 % mass fraction, respectively. For the loaded condition, this value was found as 0.48 in the case where 1 % Al2O3-TiO2-SiO2-Water and 0.47 in the case where 2 % Al2O3-TiO2-SiO2-Water nanofluid was used.

Relative humidity sensor compensation for a portable residential refrigeration dehumidifier

Households living in humid climates commonly utilize a portable refrigeration dehumidifier to control ambient relative humidity (RH). However, the built-in sensor could potentially be heated by the waste heat released from the surrounding components inside the dehumidifier, resulting in a deviation in RH measurement that leads to improper operation. In this study, such RH deviations are confirmed primarily due to the temperature difference between the ambient and internal space of the dehumidifier, which makes placing an external temperature sensor a straightforward solution. Additionally, a multiple linear regression algorithm is proposed to compensate for the RH readings. Experiment results indicate that within the typical ambient temperature and RH range (22–26 °C and 40–70%, respectively), the deviation between ambient and measured RH can range from −2.6% (at 22 °C, 40%RH) to −9.2% (at 26 °C, 70%RH). After using the proposed multiple linear regression compensation, the deviation is reduced to a range of +0.5% (at 22 °C, 70%RH) to −0.33% (at 26 °C, 55%RH), showing a satisfying 94% deviation reduction on average. Hence, the RH deviations can be eliminated efficiently by installing an external temperature sensor or using the proposed multiple linear regression compensation. The former is more generally applicable, while the latter seems more cost-effective.

Experimental Work on Solar Powered Portable Refrigeration System for Rural Areas

Abstract: The increase in demand for refrigeration globally in the field of air-conditioning, food preservation, medical services, vaccine storages, and for electronic components temperature control led to the production of more electricity and consequently an increase in the CO2 concentration in the atmosphere which in turn leads to global warming and many climatic changes. Thermoelectric refrigeration is a new alternative because it can reduce the use of electricity to produce cooling effect and also meet today’s energy challenges. Therefore, the need for thermoelectric refrigeration in developing countries is very high where long life and low maintenance are needed. The objectives of this study is to develop a working thermoelectric refrigerator to cool a volume 5L cabin that utilizes the Peltier effect to cool and maintain a selected temperature range of 5 0C to 25 0C. The cooling chamber design integrates thermoelectric modules (TEMs), which operate on the Peltier effect to cool juicer down to nearly 18’C. Solar panel added advantage to provide the energy. The design and fabrication of solar powered thermoelectric refrigerator for required applications are presented.

Multi-element Simultaneous sensitization of solution cathode glow discharge atomic emission spectrometry by using portable semiconductor anode refrigeration

In this study, a modified solution cathode glow discharge atomic emission spectrometry (SCGD-AES) was used to detect metal elements in electroplating sewage. The SCGD-AES device was equipped with a portable semiconductor anode refrigeration unit, which was built independently. The red-heat effect of tungsten electrode was alleviated by adding the portable refrigeration unit, thus improving thermal stability with the withstand voltage from 1040 V to 1140 V. Compared with the devices without semiconductor refrigeration, the chromium was excited more favorable when the discharge voltage increased, and the limit of detection (LOD) decreased by 8.5 times. Furthermore, the LODs of Zn, Cd, Ni, Cu and Pb decreased by 1.8–3.2 times, respectively, which realized the detection of elements in electroplating sewage and showed high performance in the field of trace elements analysis. Furthermore, the accuracy of the method was verified by stream sediment reference material (GBW07312), and the results were consistent with the certified values. The recoveries of elements added to industrial sewage and seawater range were from 90.5 to 98.7%, demonstrating good accuracy of the proposed method.

Emvolio - A battery operated portable refrigerator preserves biochemical and haematological integrity of biological samples in preclinical studies

Background: Emvolio is a non-medical device, indigenously developed portable refrigeration for maintaining the internal temperature 2–8˚C. The Indian Patent Office has granted patent for applications such as preservation and transport of medicines, vaccines, food, beverages, dairy etc. Further, use of Emvolio can be utilized in transport and store biologicals to preserve their biochemical and cellular integrity. The objective of this study was to evaluate the biochemical and haematological integrity of biological samples such as rat blood, serum and liver. Methods: The steady temperature was maintained inside the Emvolio, and it was compared to that of thermocol and polypropylene boxes aided with frozen gel packs. The blood and liver samples were isolated from Wistar rats and kept in Emvolio, thermocol and polypropylene boxes for 10 hrs, and the temperature was monitored. The blood parameters, namely red blood cells (RBC), white blood cells (WBC), platelets, haematocrit, haemoglobin, mean corpuscular volume (MCV), mean corpuscular haemoglobin concentration (MCHC) and red cell distribution width (RDW), serum parameters like alanine transaminase, alkaline phosphatase, total protein, albumin, creatine kinase, blood urea nitrogen and liver parameters like superoxide dismutase (SOD), glutathione (GSH), catalase were estimated and compared. Results: Emvolio maintained a constant inner temperature range of 2–8˚C, whereas a significant temperature variation was seen in thermocol and polypropylene boxes. There was no significant deviation in the parameters tested when samples were kept in Emvolio for six hours compared to the zero hour readings. In contrast, there was a significant deviation among the parameters for the samples kept in thermocol and polypropylene boxes for six hours compared to zero hour parameters. Conclusions: Emvolio maintained constant temperature and preserved the biological integrity of rat blood, serum and liver. Thus, Emvolio can be efficiently used as a biological sample carrier, especially in preclinical studies.

Comparison of pretreatment, preservation and determination methods for foliar pH of plant samples

Abstract To compare current methods of pretreatment/determination for plant foliar pH, we proposed a method for long-period sample preservation with little interference with the stability of foliar pH. Four hundred leaf samples from 20 species were collected and four methods of pH determination were used: refrigerated (stored at 4 °C for 4 days), frozen (stored at −16 °C for 4 days), oven-dried and fresh green-leaf pH (control). To explore the effects of different leaf:water mixing ratio on the pH determination results, we measured oven-dried green-leaf pH by leaf:water volume ratio of 1:8 and mass ratio of 1:10, and measured frozen senesced-leaf pH by mass ratio of 1:10 and 1:15. The standard major axis regression was used to analyze the relationship and the conversion equation between the measured pH with different methods. Foliar pH of refrigerated and frozen green leaves did not significantly differ from that of fresh green-leaf, but drying always overrated fresh green-leaf pH. During the field sampling, cryopreservation with a portable refrigerator was an advisable choice to get a precise pH. For long-duration field sampling, freezing was the optimal choice, and refrigeration is the best choice for the short-time preservation. The different leaf:water mixing ratio significantly influenced the measured foliar pH. High dilution reduced the proton concentration and increased the measured pH. Our findings provide the conversion relationships between the existing pretreatment and measurement methods, and establish a connection among pH determined by different methods. Our study can facilitate foliar pH measurement, thus contributing to understanding of this interesting plant functional trait.

Transient performance analysis of a novel design of portable magnetic refrigeration system.

The widely used ice chamber-based cold storage for the transportation and storage of vaccines has several disadvantages, including uncontrolled overall temperature, water accumulation, and frequent ice pack renewal. Therefore, in this work, we numerically studied a novel vaccine storage system by coupling magnetic refrigeration and ice packs developed by conserving the advantages of an ice-based system. A two-dimensional numerical model is developed to analyze the magnetohydrodynamic natural convection in the storage chamber. Gadolinium of 0.08 kg is used to produce a cooling power of 31.514 W and a coefficient of performance of 1.3. With the constant heat leaked of 0.828 W into the system with dimensions of (0.1 × 0.1) m, the average life of the ice pack of 0.75 kg is 1.03 h. By introducing the magnetocaloric effect, the life of the same ice pack can be infinite with no load. The dynamic mode decomposition analysis reveals that the most dominant fluid interaction occurs between the cooled gadolinium plate and the adjacent fluid, resulting in efficient cooling of the air chamber. The developed vaccine chamber design will significantly improve the existing ice pack system with a nominal increase in cost and system weight.

Design and implementation of solar powered mini refrigerator using thermoelectric cooler module

Remote areas are known for lack of conventional electrical power supply. But it is a common phenomenon to find health centres in remote areas, where vaccination campaigns are done regularly. Due to small populations, vaccines opened cannot be completely used and some usually get bad. The objective of this project is to design and implement a portable and energy efficient refrigerator for preservation of vaccines in medical centres found in remote areas where electric power supply is absent. The novelty of this work is on the use of planks, which are local materials and cheap for the construction of the frame of the refrigerator. The experimental method is used, that helps to determine the functional operation of the system and the limit to which the system functions. The main component of the refrigerator is the thermoelectric cooler module tec1-12706.The system is tested under various conditions such as simultaneous use of PV module and storage battery as source of electrical energy. The absence of cooling fan on the hot side of tec1-12706.The results show that the temperature of the system reduces from 280 C to 50c within one hour of operation. And the temperature of the hot side of the tec1-12706 module increases drastically within 15 minutes of operation if there is an absence of fan on the hot side. With this the module is easily damaged. From the literature review, the COP is maximum0.6 but the present work raises the COP to 0.7.this is done by reducing the input energy. It is then recommended that the system should not be operated without a fan attached to the hot side of the tec1 module.

Characteristics and management of scrap metal waste in Cotonou in the Republic of Benin

The development of new technology leads to the consumption of new equipment which finally becomes hazardous waste and difficult to manage. This is what was observed in the city of Cotonou in the Republic of Benin which motivated the initiative of this study, the main objective of which is to describe the mode of management of these types of waste. The data collected concerns the types of electrical and electronic equipment used by professional users and households, as well as their conditions at acquisition and their lifespans. The data were collected from households, professional users and waste pickers. After the collection, the data were entered in the Microsoft Excel 2013 spreadsheet for the analysis and then the calculations of the means, the frequencies and the production of the graphs were carried out with the SPSS 21 software. It has been revealed that among professional users, universities and administrations are major producers of scrap metal, where respectively 30% and 16% of scrap metal was recovered. According to information gathered from these players, 79% of their equipment purchases took place on the local market. At household level, radios, televisions, telephones and refrigerators are the most widely used equipment. Like other electronic and computer equipment, the households surveyed also use computers, printers, DVD players, video players, landline and portable telephones, electronic gadgets, cameras and refrigerators. At the end of its life, 66% of the households surveyed throw their equipment in the trash cans like household waste. This discarded waste is collected by the waste pickers. Among the scrap metal recovered from the latter, motorcycle and car wrecks, television sets are the most popular with respectively 16%, 15% and 14%. Next are refrigerators for 13%, batteries for 12%, followed by electronic and computer devices.

Portable Hybrid Refrigerator Prototype for Agribusiness With Its 3D Real Physical Geometry Scanned and Transferred for Simulation Software

A methodology that starts from the acquisition of real prototype geometries up to simulations to evaluate parameters, improvements, or performance under various conditions is proposed. The authors show a case study of a refrigerator with storage capacity for 50 kg of fruit solar-powered by photovoltaic panels, which reach a temperature of about 4°C. The refrigerator comprises two systems, vapor-compression, and Peltier. The methodology consisted of acquiring by a 3D laser scanner or coordinate measuring machine (CMM) and in some small complex items using 3D photogrammetry scanner. These data were transferred first as a CAD or solid works geometry and subsequently transferred to domains geometry useful for ANSYS or COMSOL simulation software. These models with high-resolution bring the simulations closer to real prototypes. Wireless sensors were installed for temperature and humidity monitoring. The analyses of the energy efficiencies of the prototype were performed. The photovoltaic system was for use in crop areas where there was no access to the urban electric network.