Solar Assisted Drying System Research Articles

Review Paper on Diffierent Types of Solar Dryer

Abstract: One of the most appealing and economical uses of solar energy is drying agricultural goods. With differing degrees of technical performance, a multitude of solar dryer types have been devised and developed across the globe. In general, solar dryers come in four different varieties: (1) direct solar dryers, (2) indirect solar dryers, (3) mixed-mode dryers, and (4) hybrid solar dryers. The product being dried, as well as technical and financial concerns, are reviewed in this paper together with other solar dryer kinds. Technically speaking, integrated storage, high efficiency, compact collector design, and long-life drying systems are the main focuses in the development of solar-assisted drying systems for vegetables. There exist alternative systems to air-based solar collectors. By using a water-to-air heat exchanger, water-based collectors are another option. A water-to-air heat exchanger can be used to push hot air used for drying agricultural products to pass through it. As part of the solar drying system, the hot water tank stores heat

Sustainability assessment of solar drying systems: a comparative life-cycle analysis of phase-change material-based vs. cylindrical solar dryers

Abstract Solar drying systems are becoming a popular alternative to traditional energy-based drying systems for agricultural products due to their effectiveness and reduced fuel consumption. Although the efficiency of solar drying systems has been thoroughly investigated, their sustainability has not been studied enough. This study aims to fill that gap by conducting a life-cycle assessment of two new solar drying systems built in Udaipur, Rajasthan, India. The environmental implications of an innovative cylindrical solar-assisted drying system and a phase-change material-based solar drying system were evaluated using cradle-to-gate life-cycle analysis. The study uses the ReCiPe 2016 endpoints (H) technique to calculate various aspects such as midpoint, endpoint, single score, normalization result, and network diagram for phase-change material-based solar drying and cylindrical solar-assisted drying. Results show that phase-change material-based solar drying has an average of 40% more impact on the environment than cylindrical solar-assisted drying, with a high impact found in human non-carcinogenic toxicity, mainly due to the production of phase-change materials. However, cylindrical solar-assisted drying system crossover phase-change material based solar drying in terms of its impact on human carcinogenic toxicity and fossil resource scarcity. The contribution to global warming of phase-change material-based solar drying is 13.7% more than that of cylindrical solar-assisted drying. The endpoint characterization indicates that phase-change material-based solar drying exceeds in terms of human health (40%) and ecosystem (37.04%), whereas cylindrical solar-assisted drying surpasses phase-change material-based solar drying in terms of impacts on resources, at 14%. The early drying in phase-change material-based solar drying makes up for its higher impact than that in cylindrical solar-assisted drying, which takes 3 hours longer to dry. This study offers guidance and methods for making the best choice of solar-powered dryers.

Drying of Nettle Using Concentrated Air Collector and Concentrated Photovoltaic Thermal Supported Drying System and Modeling with Machine Learning

This study examines the performance of a solar assisted drying system in the nettle drying process. The drying process works by using thermal energy obtained from solar air collectors and PV modules. The experimental were carried out in October 2022, and the room temperature, total efficiency and moisture content parameters were investigated. The data obtained from the drying system were modelled using machine learning algorithms such as artificial neural networks (ANN), support vector machines (SVM), and gradient boosting decision trees (GBDT). The average thermal energy transferred to the drying cabin was calculated as 154 W, with 77% of this energy was obtained from the air collector and the remaining 23% from the PV module. The stinging nettle was dried from an initial moisture content of 11.18 g water/g dry matter to a final moisture content of 1.18 g water/g dry matter. The average total efficiency of the drying system was found to be 16.8%. Additionally, the results show that the SVM algorithm exhibits the best performance in estimating important parameters such as chamber temperature, moisture content, and total efficiency. Especially in total efficiency prediction. The SVM algorithm has a significant advantage over other algorithms. As a result, it was concluded that the SVM algorithm can be used effectively utilized in solar energy-supported drying systems and can be a precious choice for the optimization of the drying process.

Influences of a novel cylindrical solar dryer on farmer's income and its impact on environment.

Poor grain drying facilities, along with the burden of drying cost, bound the farmers to market their produce soon after harvest. Thus, this research paper intends to study the influences of a novel cylindrical solar-assisted dryer on farmers' income and its impact on the environment. The paper also presents the design and fabrication of a drying system for maize cobs using non-conventional solar energy. The performance of the solar-assisted drying system was also investigated for drying of yellow dent maize cobs. As a very energy-intensive post-harvest process, drying consumes a lot of electricity, which is usually provided by conventional energy. Here, solar dryers are the perfect solution in terms of efficiency, uniform drying of agricultural food products, less drying time, increased marketability of agricultural products, and reducing the load on farmer's pocket for drying. With a high internal rate of return of 66 percent, the designed dryer proved to be technically and economically viable. Compared to open sun drying, the solar drying system produced better quality and drying time results. Compared to other models, the Midilli model fits the experimental maize drying data better, with a coefficient of determination of R2 = 0.89729. Energy analysis inferred savings of 1352.97 kWh electrical energy and 128.18 liters of diesel fuel plus a reduction of 1.22 t CO2 per annum can be achieved by using this dryer.

A literature research on the drying quality of agricultural products with using solar drying technologies

Solar energy is a green and renewable clean energy. Using this as main or auxiliary energy to dry agricultural materials could reduce energy consumption and improve product quality. In the drying process of agricultural materials, not only drying technologies but also drying parameters would affect the quality of materials.This paper provides a guided technological tour on solar drying through a literature research. An overview about the drying technologies to evaluate the drying quality, such as traditional sun drying, solar tunnel drying, solar greenhouse drying, solar-assisted drying system, is presented to demonstrate advances and application potential of solar drying. Finally, variable temperature drying is preliminarily proposed and tested to verify its superiority of energy saving and drying quality improvement. The literature research in this paper gives a reference on the effective application of solar drying through specifying the mechanisms of quality transformation.

Estimation of the Experimental Drying Performance Parameters Using Polynomial SVM and ANN Models

The utilization of solar energy in Turkey is very popular because of yearly high solar radiation compared to other countries. One of the common usage area of solar energy is food drying processes. Foods are generally dried under direct sunlight. However, the quality of the dried product exposed to solar radiation reduces. Additionally, the food product dried in outdoors is also exposed to the negative effects of the external environment and thus adversely affects the product quality. In order to overcome these problems, many studies are carried out on solar assisted drying systems. It is very important to calculate or modeling the drying parameters for the design of solar assisted drying systems. In recent years, interest on calculative intelligence methods increases due to the fact that it has high predictive power in modeling of systems. In this study, performance parameters such as solar collector efficiency (ηc), drying rate (DR) and convective heat transfer coefficient (hc) obtained from a solar energy assisted dryer for different products were estimated by Support Vector Machine (SVM) and Artificial Neural Network (ANN) models. The accuracy criteria of the predicted results for each model were determined and compared. It was shown from the results that the best converging models of DR and ηc parameters were ANN and SVMC, respectively. However, it was observed that SVML was the best convergent model for hc values obtained from apple product, and ANN model was the best convergent model for hc values obtained from other products.

Thin layer drying of zucchini in solar dryer located in Osmaniye region

In this study, the dehydration behavior of zucchini using solar assisted drying system was examined according to 22 thin layer drying models available in literature. The correlation coefficient (R2), chi-square (χ2) and root mean square error (RMSE) values were calculated to check the suitability of models by non-linear regression analysis. It was found that Cubic and Modified Midilli-1 models were the most suitable equations and their R2 values were calculated as 0.99963. χ2 and RMSE values of related mathematical expressions were 1.89343×10‒5, 1.91692×10‒5 and 0.01685×10‒3, 0.01721×10‒3 respectively. In addition, heat transfer, mass transfer and diffusion coefficients, which were important parameters in design of drying systems were also determined as 5.18124 W/m2°C, 1.57129×10‒7 m/s and 2.335718×10‒9 m2/s respectively.

Research and Development Work on Solar Assisted Drying Systems

The solar energy research group from Solar Energy Research Institute (SERI), Universiti Kebangsaan Malaysia (UKM) has designed and constructed solar assisted drying systems for drying agricultural and marine products. This study is a review of numerous types of solar dryer systems developed by SERI, UKM. The classification of solar drying systems has divided by two namely air based solar collector systems and water based solar collector systems. Drying with solar assisted drying systems was found to be a viable option with many benefits such as protected drying environment, improved dried quality of products and reduces drying time compared with the traditional sun drying method. Therefore, SERI’s solar assisted drying system shows a great potential for application in drying process of agricultural and marine products.

ADVANCED SOLAR ASSISTED DRYING SYSTEMS FOR MARINE AND AGRICULTURAL PRODUCTS

Solar assisted drying systems are cost effective and suitable for drying of various marine andagricultural products. The way forward for advanced solar assisted drying systems is compact collector design,high efficiency, integrated storage, and long-life systems. Air based solar collectors are not the only availablesystems. Water based collectors can also be used whereby water to air heat exchanger can be used. The hot airfor drying of agricultural produce can be forced to flow in the water to air heat exchanger. The hot water tankacts as heat storage of the solar drying system. Heat pump drying system can be effective use for as part of solarassisted drying systems. Moreover, innovative applications of photovoltaic thermal system for simultaneousproduction of heat and electricity are suitable as standalone applications and totally operated on solar energy.The Solar Energy Research Institute has developed four advanced solar assisted drying system suitable fordrying of various marine and agricultural products namely (a) the solar assisted drying systems with thedouble-pass solar collector with fins (b) solar assisted dehumidification system (c) solar assisted chemical heatpump system and (d) solar assisted heat pump with photovoltaic thermal collectors.DOI: http://dx.doi.org/10.3329/jme.v42i1.15912

Development of a Solar Assisted Drying System Using Double-Pass Solar Collector with Finned Absorber

The Solar Energy Research Group, Universiti Kebangsaan Malaysia, International Islamic University Malaysia and Yayasan FELDA has designed and constructed a solar assisted drying system at OPF FELDA Factory, Felda Bukit Sagu 2, Kuantan, Pahang. The drying system has a total of six double-pass solar collectors. Each collector has a length of 480 cm and a width of 120 cm. The first channel depth is 3.5 cm and the second channel depth is 7 cm. Longitudinal fins made of angle aluminium, 0.8 mm thickness were attached to the bottom surface of the absorber plate. The solar collectors are arranged as two banks of three collectors each in series. Internal manifold are used to connect the collectors. Air enters through the first channel and then through the second channel of the collector. An auxiliary heater source is installed to supply heat under unfavourable solar radiation condition. An on/off controller is used to control the startup and shutdown of the auxiliary heater. An outlet temperature of 70–75 °C can be achieved at solar radiation range of 800–900 W/m2 and flow rate of 0.12 kg/s. The average thermal efficiency of a solar collector is approximately 37%.

Design and performance evaluation of a solar-assisted drying system

A solar air heating system that does not require a conventional auxiliary heater, but can still provide a daily load fraction exceeding 90% and supply hot air at a steady temperature and flow rate continuously for ten hours a day, has been developed. The system, which combines flat plate solar collector heat exchanger and blower, was evaluated by drying Aonla and Cabbage using air at 60°C and 90 m³/h. The Aonla was dried from 80.0% moisture (w.b) to 7.29% over 20 hours of continuous drying. The dryer reduced the drying time by 70% compared to open sun drying, and provided 92.5% load fraction during the ten-hour operation. The temperature of hot air supplied was stable at 60±3°C for about ten hours for two days during the entire drying duration.

Optimization of a solar-assisted drying system for drying bananas

This paper presents a mathematical model for optimal design of a solar-assisted drying system for drying bananas. The optimization model consists of a simulation model of a solar-assisted drying system combined with an economic model. The simulation model is composed of two systems of differential equations: one for the collector and other for the drying cabinet. These systems of the differential equation were solved using the finite difference method. Values of the model parameters were determined experimentally. A computer program in FORTRAN was developed to simulate the performance of the drying system. The model was validated by comparing the simulation results with the experimental results and they were in good agreement. This simulation model was used for the optimization of the solar-assisted drying system. An economic model was formulated to calculate the annual drying cost. The optimization problem was defined as the optimization of the geometry and operational parameters of the drying system so as to minimize the drying cost per unit of dried product. Currently used collector area and the air recycle factor were considered as the parameters for basic mode of operation of the drying system. The adaptive pattern search technique was adopted to find the optimum values of the solar collector area and the recycle factor. The optimum values of the collector area and the recycle factor were found to be 26 m 2 and 90%, respectively. The computer program developed in this study can be used to optimize similar drying systems.

Drying chamber performance of V-groove forced convective solar dryer

The performance of the drying chamber of a solar assisted drying system was analyzed. The solar assisted drying system consists of drying chamber, V-groove collector of 13.8 mð area, the auxiliary heater and two variable speed centrifugal fans. K-type thermocouples were used for temperature measurement, while solar radiation was measured by Eppley Pyranometer. Drying temperature is considered the most important factor in the drying operation. The accuracy of the temperature measurement is important in this analysis. The procedure for calculating the heat losses from drying chamber may be quite complex and often difficult to accurately determine the numerous variables. In this work standard equations under steady state condition were used to calculate the drying chamber efficiency and the heat losses from the chamber room.

Double-Pass Solar Collectors with Porous Media Suitable for Higher-Temperature Solar-Assisted Drying Systems

A high-performance solar collector suitable for a solar-assisted drying system was designed, fabricated, and tested. Solar-assisted drying systems consist of the solar collector array, auxiliary heater, drying chamber, and the air distribution systems. The solar collector was a double-pass solar collector and has upper and lower channels. The lower channel of the solar collector was filled up with porous media, which also acts as a storage medium. The outlet temperature and the performance of the system increased with the presence of the porous media. The collector width and length are 120 and 240 cm , respectively. The upper channel depth is 3.5 cm and the lower channel depth is 10.5 cm . The solar collector array consists of six solar collectors, arranged as two banks of three collectors in series. The collectors were joined in series using internal manifolding. A temperature of 90°C can be reached at a solar radiation level of 800 W∕ m2 , ambient temperature of 30°C , and mass flow rate of 0.06 kg∕s . ...

Development of advanced solar assisted drying systems

The Solar Energy Research Group in the Universiti Kebangsaan Malaysia has been set-up more than two decades ago. One of the activities is in the field of solar thermal process, particularly in development of solar assisted drying systems. Solar drying systems technical development can proceed in two directions. Firstly simple, low power, short life, and comparatively low efficiency-drying system. Secondly, the development of high efficiency, high power, long life expensive solar drying system. The group has developed four solar assisted drying systems namely (a) the V-groove solar collector, (b) the double-pass solar collector with integrated storage system, (c) the solar assisted dehumidification system for medicinal herbs and (d) the photovoltaic thermal (PVT) collector system. The common problems associated with the intermittent nature of solar radiation and the low intensities of solar radiation in solar thermal systems can be remedied using these types of solar drying systems. These drying systems have the advantages of heat storage, auxiliary energy source, integrated structure control system and can be use for a wide range of agricultural produce.

A simplified technique for sizing solar-assisted fixed-bed batch dryers: application to granulated natural rubber

This work concerns the design of solar-assisted drying systems. The system considered is of indirect type where an air collector field is associated to a fixed-bed batch dryer. For a given system configuration, the heat savings fraction is defined. Partial drying air recirculation and the possible heat dumping are taken into account. The importance of the collector array is underlined. A simplified technique for sizing is developed with application to granulated natural rubber for fixed drying conditions. The development consists in relating empirically the heat savings fraction to design parameters by simulations.

Experimental results of a solar assisted heat pump rice drying system

In the last rice harvest season, experimental results have been obtained on the efficiency and drying quality of a solar assisted heat pump drying prototype system. The system has been operated as a solar and heat pump system and drying curves for the different options have been obtained. The advantage of the low temperature and better control in the drier shows that the heat pump assisted solar drying system is an excellent alternative to traditional drying systems.