Submitted Successfully!
To reward your contribution, here is a gift for you: A free trial for our video production service.
Thank you for your contribution! You can also upload a video entry or images related to this topic.
Version Summary Created by Modification Content Size Created at Operation
1
Lisete Fernandes
 -- 1219 2024-01-16 12:31:11 |
2 layout
Jessie Wu
 + 3 word(s) 1222 2024-01-17 02:12:44 | |
3 layout
Jessie Wu
 + 1 word(s) 1223 2024-01-17 02:13:34 |

Video Upload Options

We provide professional Video Production Services to translate complex research into visually appealing presentations. Would you like to try it?
No, upload directly Yes

Confirm

Are you sure to Delete?
Yes No
Cite
If you have any further questions, please contact Encyclopedia Editorial Office.
Fernandes, L.; Tavares, P.B. Hybrid Solar Dryers. Encyclopedia. Available online: https://encyclopedia.pub/entry/53894 (accessed on 31 December 2024).
Fernandes L, Tavares PB. Hybrid Solar Dryers. Encyclopedia. Available at: https://encyclopedia.pub/entry/53894. Accessed December 31, 2024.
Fernandes, Lisete, Pedro B. Tavares. "Hybrid Solar Dryers" Encyclopedia, https://encyclopedia.pub/entry/53894 (accessed December 31, 2024).
Fernandes, L., & Tavares, P.B. (2024, January 16). Hybrid Solar Dryers. In Encyclopedia. https://encyclopedia.pub/entry/53894
Fernandes, Lisete and Pedro B. Tavares. "Hybrid Solar Dryers." Encyclopedia. Web. 16 January, 2024.
Hybrid Solar Dryers
Edit
This entry is adapted from the peer-reviewed paper 10.3390/solar4010002

Hybrid solar dryers, by definition, designed and constructed using direct solar energy and a heat exchanger. The products are dried under direct solar radiation and/or backup energy or stored heat when sunlight is not available. These types of dryers are used in single and mixed modes of drying. Several studies have been developed to test different techniques to improve solar dryers, considering the possible use of thermal storage materials, the deep bed drying method, improved solar collector designs and energy hybridization. They can be divided several ways, depending on their construction.

solar energy types of dryers dryers designs food application

1. With Thermal Energy Storage (TES)

Due to the limitation of solar dryers operating only during sunlight hours, thermal storage emerges as a great solution. It allows the stored heat to be used during the night, ensuring continuous drying and preventing rehydration of the products. During off-sunshine hours, microbial activity may lead to the growth of microorganisms and the extended drying periods can degrade the quality of agricultural products, resulting in poor product quality and spoilage [1][2][3][4][5][6][7][8][9][10].
The integration of a thermal energy storage (TES) unit is needed, and numerous studies have tested it. Some authors divided it into:
  • Sensible heat storage (SHS): materials are heated to store excess solar energy, depending on their specific heat capacity, mass and temperature. The best properties of these materials are density, thermal conductivity and stability. For example, materials such as brick, aluminum, gravel, river rocks, concrete, granite and limestone can be used. The rock bed is the most common material for sensible storage used in solar dryer systems [11][12];
  • Latent heat storage (LHS): in this kind of material, solar energy is stored during the phase change process. The phase change materials (PCM) can be organic (such as paraffin, like wax n-alkanes and methyl groups) or non-paraffin types (like fatty acids, glycols, alcohols and esters), inorganic (salt hydrates and metallic) or eutectic composition [6][13];
  • Thermo-chemical energy storage (TCES): it is based on the principle that all chemical reactions either absorb or release heat. This process stores energy by using high-energy chemical processes. In this case, the heat stored depends on the amount of storage material, the endothermic heat of the reaction and the extent of conversion [14][15][16].

2. With an Auxiliary Unit

The dryer can operate on solar energy, but for additional heating, auxiliary units are used. The most common are fuelled with fossil fuel or biomass to reach and maintain the required temperature. Despite their effectiveness, their availability is limited, and they are associated with environmental pollution issues. Amer and Gottschalk [17] used electric resistances as auxiliary units in fresh chamomile drying; Matouk et al. [18] used them for onion slices; and Hossain et al. [19] used them for tomato slices [20]. Ferreira et al. [21] applied 20 incandescent lamps, 100 W each, for drying banana slices. Suherman et al. [22] used SUS (stainless steel) plates as heat collectors for solar radiation and an LPG (liquefied petroleum gas) burner in seaweed drying. Many studies have been conducted on this type of dryer in various contexts [23].

3. With Photovoltaic (PV)

Solar dryers with photovoltaic (PV) assistance are probably the most widely used. Thermal energy can be obtained from solar radiation by using solar collectors and it is converted via PV panels into direct current electricity [24]. These kinds of systems have a huge variety of possible configurations and can range from the simplest forms, such as powering fans to provide air circulation, to making a significant contribution to the decarbonization of electricity production. The PV-ventilated system is very common in greenhouse dryers [25][26][27][28][29][30]. The integrated arrangement for applying thermal energy as well as electrical energy with a PV module is referred to as a hybrid PV/T system [31][32][33][34][35][36][37][38][39][40][41]. The integration of PV panels with solar dryers ensures a continuous and reliable power supply, reducing dependency on the grid and further promoting sustainability in the drying process.

4. With Heat Pump

Some authors defend that combining a solar thermal energy source, such as solar thermal collectors with a heat pump dryer, will assist in reducing the operation cost of drying and producing products of high quality [42]. The aim of installing a heat pump is to solve the problem of the intermittent availability of solar radiation. Depending on weather conditions, four working modes can be chosen [43][44][45][46][47][48][49][50][51][52][53][54]:
  • Solar energy heating mode, when solar radiation is sufficient during the daytime;
  • Heat pump heating mode when solar radiation is unavailable;
  • Solar-assisted heat pump heating mode, when solar radiation is insufficient during the daytime;
  • Heat pump dehumidification mode when ambient humidity is high.
Beyond all the drying designs associated with heat pump systems, some authors also consider solar systems with chemical heat pumps (CHP) and solar systems with dehumidification systems [55].
The chemical reactions in a CHP system are generally reversible, enabling the alteration of the temperature level of the thermal energy stored by chemical substances [56][57]. These reactions are crucial for absorbing and releasing heat. Typically, the main components include an evacuation system, a storage tank, a chemical heat pump and a drying chamber. CHP can be categorized into solid–gas [58] and liquid–gas.
A solid–gas chemical heat pump unit consists of a reactor or adsorber, an evaporator and a condenser. Liquid–gas systems have at least two reactors: endothermic and exothermic. The high storage capacity, low heat loss and long-term storage of reactants and products are the principal advantages of CHP [59].
Regarding dehumidification systems, in general, fresh products have high moisture contents. Using a desiccant material, such as silica, alumina, pillared clay, or zeolite [60][61][62], may consume low energy and produce dry air to improve drying performance. The pressure difference of generated water vapor, even at low temperatures, can improve driving force that is proportional to the evaporation rate. As a result, energy efficiency can be potentially improved while maintaining product quality [63].
Heat pump dryers come in different types and their performance varies depending on the type. The ability to control the temperature of the drying air and humidity while recovering energy from exhaust is one of the primary advantages of heat pump dryers; however, the environmental impacts is still not well known [64].

5. With Geothermal or Waste Waters

This kind of dryer uses solar radiation in combination with a low-potential energy source, such as geothermal or wastewater. The installation allows for the combination of conventional or nonconventional energy sources [65]. According to Ivanova and Andonov [66], it is possible to achieve continuous drying, even during the night, enabled by additional heating of the air during movement in the collector using this source of energy, in a clean and cost-effective mode, as renewable energies are used. The system includes a stainless-steel body, heat exchanger, piping, dehumidifier, blower and trays [67].
Based on the design, construction material used, energy backup systems and auxiliary heating units, several variants of solar dryers for drying foods have been described. These diverse configurations allow for customized solutions to suit specific drying requirements, optimizing energy efficiency and ensuring consistent drying performance across different applications. The integration of low-potential energy sources with solar radiation enhances the versatility and reliability of solar dryers, making them more sustainable and resilient in various operating conditions.
Several studies are being conducted to test different techniques for improving solar dryers, including the use of thermal storage materials, deep bed drying methods, enhanced solar collector designs and energy hybridization. As we can observe, there are a wide variety of solar dehydrators with different shapes and operating modes.

References

  1. Reyes, A.; Mahn, A.; Cubillos, F.; Huenulaf, P. Mushroom dehydration in a hybrid-solar dryer. Energy Convers. Manag. 2013, 70, 31–39.
  2. Jain, D. Modeling the system performance of multi-tray crop drying using an inclined multi-pass solar air heater with in-built thermal storage. J. Food Eng. 2005, 71, 44–54.
  3. Kant, K.; Shukla, A.; Sharma, A.; Kumar, A.; Jain, A. Thermal energy storage based solar drying systems: A review. Innov. Food Sci. Emerg. Technol. 2016, 34, 86–99.
  4. Bareen, A.; Dash, S.; Kalita, P.; Dash, K.K. Experimental investigation of an indirect solar dryer with PCM-integrated solar collector as a thermal energy storage medium. Environ. Sci. Pollut. Res. 2023.
  5. Barbosa, E.G.; de Araujo, M.E.V.; de Oliveira, A.C.L.; Martins, M.A. Thermal energy storage systems applied to solar dryers: Classification, performance and numerical modeling: An updated review. Case Stud. Therm. Eng. 2023, 45, 102986.
  6. Srinivasan, G.; Rabha, D.K.; Muthukumar, P. A review on solar dryers integrated with thermal energy storage units for drying agricultural and food products. Sol. Energy 2021, 229, 22–38.
  7. Suresh, B.V.; Shireesha, Y.; Kishore, T.S.; Dwivedi, G.; Haghighi, A.T.; Patro, E.R. Natural energy materials and storage systems for solar dryers: State of the art. Sol. Energy Mater. Sol. Cells 2023, 255, 112276.
  8. Ekka, J.P.; Kumar, D. A review of industrial food processing using solar dryers with heat storage systems. J. Stored Prod. Res. 2023, 101, 102090.
  9. Bal, L.M.; Satya, S.; Naik, S.N. Solar dryer with thermal energy storage systems for drying agricultural food products: A review. Renew. Sustain. Energy Rev. 2010, 14, 2298–2314.
  10. Atalay, H. Assessment of energy and cost analysis of packed bed and phase change material thermal energy storage systems for the solar energy-assisted drying process. Sol. Energy 2020, 198, 124–138.
  11. Le, T.S.; Le, T.H.; Pham, M.T. A review of the indirect solar dryer with sensible heat storage mediums. J. Mech. Eng. Res. Dev. 2021, 44, 131–140.
  12. Dincer, I.; Rosen, M.A. Thermal Energy Storage Systems and Applications, 2nd ed.; Wiley: Hoboken, NJ, USA, 2021; Available online: https://www.mendeley.com/catalogue/01fdef10-9cbe-348d-b047-c1fa4704b3eb/?utm_source=desktop&utm_medium=1.19.8&utm_campaign=open_catalog&userDocumentId=%7Bfeb3922d-e583-4d27-af02-eb86801f2975%7D (accessed on 10 May 2023).
  13. Ebrahimi, H.; Samimi Akhijahani, H.; Salami, P. Improving the thermal efficiency of a solar dryer using phase change materials at different position in the collector. Sol. Energy 2021, 220, 535–551.
  14. Zhang, H.; Smith, J.D. Investigating influences of geometric factors on a solar thermochemical reactor for two-step carbon dioxide splitting via CFD models. Sol. Energy 2019, 188, 935–950.
  15. Carrillo, A.J.; González-Aguilar, J.; Romero, M.; Coronado, J.M. Solar Energy on Demand: A Review on High Temperature Thermochemical Heat Storage Systems and Materials. Chem. Rev. 2019, 119, 4777–4816.
  16. Garofalo, L.; Vitiello, F.V.; Montagnaro, F.; Bürgmayr, H.; Winter, F. Salt Hydrates for Thermochemical Storage of Solar Energy: Modeling the Case Study of Calcium Oxalate Monohydrate Dehydration/Rehydration under Suspension Reactor Conditions. Ind. Eng. Chem. Res. 2021, 60, 11357–11372.
  17. Amer, B.; Gottschalk, K. Drying of Chamomile Using a Hybrid Solar Dryer. CIGR-World Congr. 2012. Available online: https://www.researchgate.net/publication/256457594_Drying_of_Chamomile_Using_a_Hybrid_Solar_Dryer (accessed on 22 April 2023).
  18. Matouk, A.; EL-Kholy, M.; Tharwat, A.; Elfar, S.; Shehata, E. Drying of Onion Slices Using Hybrid Solar Dryer. J. Soil. Sci. Agric. Eng. 2021, 12, 491–498.
  19. Hossain, M.A.; Amer, B.M.A.; Gottschalk, K. Hybrid solar dryer for quality dried tomato. Dry. Technol. 2008, 26, 1591–1601.
  20. Rodrigues, L.J.; Basso, D.M. Hybrid system simulation to supply heated air to a solar food dryer. Eng. Agric. 2020, 40, 154–161.
  21. Ferreira, A.G.; Charbel, A.L.T.; Pires, R.L.; Silva, J.G.; Maia, C.B. Experimental Analysis of a Hybrid Dryer. Rev. Eng. Térmica. 2007, 6, 3.
  22. Suherman, S.; Rizki, H.; Rauf, N.; Susanto, E.E. Performance study of hybrid solar dryer with auxiliary heater for seaweed drying. In Journal of Physics: Conference Series; IOP Publishing: Bristol, UK, 2019; Volume 1295.
  23. Nukulwar, M.R.; Tungikar, V.B. Recent development of the solar dryer integrated with thermal energy storage and auxiliary units. Therm. Sci. Eng. Prog. 2022, 29, 101192.
  24. Srimanickam, B.; Kumar, S. Drying investigation of coriander seeds in a photovoltaic thermal collector with solar dryer. J. Therm. Eng. 2023, 9, 659–668.
  25. Garg, H.P.; Kumar, R. Studies on semi-cylindrical solar tunnel dryers: Thermal performance of collector. Appl. Therm. Eng. 2000, 20, 115–131.
  26. Condorí, M.; Echazú, R.; Saravia, L. Solar drying of sweet pepper and garlic using the tunnel greenhouse drier. Renew. Energy 2001, 22, 447–460.
  27. Farhat, A.; Kooli, S.; Kerkeni, C.; Maalej, M.; Fadhel, A.; Belghith, A. Validation of a pepper drying model in a polyethylene tunnel greenhouse. Int. J. Therm. Sci. 2004, 43, 53–58.
  28. Janjai, S.; Khamvongsa, V.; Bala, B.K. Development, designand performance of a PV-Ventilated greenhouse dryer. Int. Energy J. 2007, 8, 249–258.
  29. Janjai, S.; Lamlert, N.; Intawee, P.; Mahayothee, B.; Bala, B.K.; Nagle, M.; Müller, J. Experimental and simulated performance of a PV-ventilated solar greenhouse dryer for drying of peeled longan and banana. Sol. Energy 2009, 83, 1550–1565.
  30. Patil, R.; Gawande, R. A review on solar tunnel greenhouse drying system. Renew. Sustain. Energy Rev. 2016, 56, 196–214.
  31. John, M.K.; Bandaru, R.; Muraleedharan, C. Experimental analysis of wavy mesh assisted solar drying system with a survey of common drying technologies employed by farmers. Sustain. Energy Technol. Assess. 2023, 56, 103049.
  32. Barnwal, P.; Tiwari, G.N. Grape drying by using hybrid photovoltaic-thermal (PV/T) greenhouse dryer: An experimental study. Sol. Energy 2008, 82, 1131–1144.
  33. Punlek, C.; Pairintra, R.; Chindaraksa, S.; Maneewan, S. Simulation design and evaluation of hybrid PV/T assisted desiccant integrated HA-IR drying system (HPIRD). Food Bioprod. Process. 2009, 87, 77–86.
  34. Daghigh, R.; Shahidian, R.; Oramipoor, H. A multistate investigation of a solar dryer coupled with photovoltaic thermal collector and evacuated tube collector. Sol. Energy 2020, 199, 694–703.
  35. Fterich, M.; Chouikhi, H.; Bentaher, H.; Maalej, A. Experimental parametric study of a mixed-mode forced convection solar dryer equipped with a PV/T air collector. Sol. Energy 2018, 171, 751–760.
  36. Kong, D.; Wang, Y.; Li, M.; Keovisar, V.; Huang, M.; Yu, Q. Experimental study of solar photovoltaic/thermal (PV/T) air collector drying performance. Sol. Energy 2020, 208, 978–989.
  37. Ozsolak, F.; Milos, P.M. A Review of Photovoltaic Thermal (PVT) Technology for Residential Applications. Nat. Rev. Genet. 2010, 12, 87–98. Available online: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3031867&tool=pmcentrez&rendertype=abstract%5Cn (accessed on 18 June 2023).
  38. Shahsavar, A.; Ameri, M. Experimental investigation and modeling of a direct-coupled PV/T air collector. Sol. Energy 2010, 84, 1938–1958.
  39. Ahn, J.G.; Kim, J.H.; Kim, J.T. A study on experimental performance of air-type PV/T collector with HRV. Energy Procedia 2015, 78, 3007–3012.
  40. Zhang, X.; Zhao, X.; Smith, S.; Xu, J.; Yu, X. Review of R&D progress and practical application of the solar photovoltaic/thermal (PV/T) technologies. Renew. Sustain. Energy Rev. 2012, 16, 599–617.
  41. Goud, M.; Reddy, M.V.V.; Chandramohan, V.P.; Suresh, S. A novel indirect solar dryer with inlet fans powered by solar PV panels: Drying kinetics of Capsicum Annum and Abelmoschus esculentus with dryer performance. Sol. Energy 2019, 194, 871–885.
  42. Assadeg, J.; Alwaeli, A.H.A.; Sopian, K.; Moria, H.; Hamid, A.S.A.; Fudholi, A. Solar assisted heat pump system for high quality drying applications: A critical review. Int. J. Renew. Energy Res. 2020, 10, 303–316.
  43. Wang, Y.; Li, M.; Qiu, Y.; Yu, Q.; Luo, X.; Li, G.; Ma, X. Performance analysis of a secondary heat recovery solar-assisted heat pump drying system for mango. Energy Explor. Exploit. 2019, 37, 1377–1387.
  44. Fayose, F.; Huan, Z. Heat pump drying of fruits and vegetables: Principles and potentials for Sub-Saharan Africa. Int. J. Food Sci. 2016, 2016, 9673029.
  45. Hasan Ismaeel, H.; Yumrutaş, R. Investigation of a solar assisted heat pump wheat drying system with underground thermal energy storage tank. Sol. Energy 2020, 199, 538–551.
  46. Cervantes, J.G.; Torres-Reyes, E. Experiments on a solar-assisted heat pump and an exergy analysis of the system. Appl. Therm. Eng. 2002, 22, 1289–1297.
  47. Yahya, M.; Fahmi, H.; Fudholi, A.; Sopian, K. Performance and economic analyses on solar-assisted heat pump fluidised bed dryer integrated with biomass furnace for rice drying. Sol. Energy 2018, 174, 1058–1067.
  48. Şevik, S. Experimental investigation of a new design solar-heat pump dryer under the different climatic conditions and drying behavior of selected products. Sol. Energy. 2014, 105, 190–205.
  49. Chapchaimoh, K.; Poomsa-Ad, N.; Wiset, L.; Morris, J. Thermal characteristics of heat pump dryer for ginger drying. Appl. Therm. Eng. 2016, 95, 491–498.
  50. Aktas, T.; Ulger, P.; Daglioglu, F.; Hasturk, F. Changes of nutritional and physical quality characteristics during storage of osmotic pretreated apple before hot air drying and sensory evaluation. J. Food Qual. 2013, 36, 411–425.
  51. Duan, Q.; Wang, D.; Li, X.; Li, Y.; Zhang, S. Thermal characteristics of a novel enclosed cascade-like heat pump dryer used in a tunnel type drying system. Appl. Therm. Eng. 2019, 155, 206–216.
  52. Ceylan, I.; Gürel, A.E. Solar-assisted fluidized bed dryer integrated with a heat pump for mint leaves. Appl. Therm. Eng. 2016, 106, 899–905.
  53. Li, Y.; Li, H.F.; Dai, Y.J.; Gao, S.F.; Wei, L.; Li, Z.L.; Odinez, I.G.; Wang, R.Z. Experimental investigation on a solar assisted heat pump in-store drying system. Appl. Therm. Eng. 2011, 31, 1718–1724.
  54. Kang, H.; Zhang, G.; Mu, G.; Zhao, C.; Huang, H.; Kang, C.; Li, X.; Zhang, Q. Design of a Greenhouse Solar-Assisted Heat Pump Dryer for Kelp (Laminaria japonica): System Performance and Drying Kinetics. Foods 2022, 11, 3509.
  55. Tiwari, A. A Review on Solar Drying of Agricultural Produce. J. Food Process Technol. 2016, 7, 1000623.
  56. Kawasaki, H.; Watanabe, T.; Kanzawa, A. Proposal of a chemical heat pump with paraldehyde depolymerization for cooling system. Appl. Therm. Eng. 1999, 19, 133–143.
  57. Ogura, H.; Mujumdar, A.S. Proposal for a novel chemical heat pump dryer. Dry. Technol. 2000, 18, 1033–1053.
  58. Yu, Y.Q.; Zhang, P.; Wu, J.Y.; Wang, R.Z. Energy upgrading by solid-gas reaction heat transformer: A critical review. Renew. Sustain. Energy Rev. 2008, 12, 1302–1324.
  59. Fadhel, M.I.; Sopian, K.; Daud, W.R.W. Performance analysis of solar-assisted chemical heat-pump dryer. Sol. Energy 2010, 84, 1920–1928.
  60. Ramli, M.S.A.; Misha, S.; Haminudin, N.F.; Rosli, M.A.M.; Yusof, A.A.; Sopian, K.; Ibrahim, A.; Abdullah, A.F. Dehumidification of recirculation air from solar dryer using silica gel for food product drying. In Proceedings of Mechanical Engineering Research Day 2022, Melaka, Malaysia, 13 July 2022; UTeM Press: Melaka, Malaysia, 2022; pp. 170–171.
  61. Djaeni, M.; Utari, F.D.; Sasongko, S.B.; Kumoro, A.C. Evaluation of food drying with air dehumidification system: A short review. In IOP Conference Series: Earth and Environmental Science; IOP Publishing: Bristol, UK, 2018; Volume 102.
  62. El Miz, M.; Salhi, S.; Chraibi, I.; El Bachiri, A.; Fauconnier, M.-L.; Tahani, A. Characterization and Adsorption Study of Thymol on Pillared Bentonite. Open J. Phys. Chem. 2014, 4, 98–116.
  63. Yahya, M.; Sopian, K.; Daud, W.R.W.; Othman, M.Y.; Yatim, B. Performance of a solar assisted dehumidification system for Centella asiatica L. In Proceedings of the 8th WSEAS International Conference on Power Systems, Santander, Cantabria, Spain, 23–25 September 2008; pp. 306–311. Available online: https://api.semanticscholar.org/CorpusID:55676223 (accessed on 8 July 2023).
  64. Loemba, A.B.T.; Kichonge, B.; Kivevele, T. Comprehensive assessment of heat pump dryers for drying agricultural products. Energy Sci. Eng. 2022, 11, 2985–3014.
  65. Delgado-Plaza, E.; Peralta-Jaramillo, J.; Quilambaqui, M.; Gonzalez, O.; Reinoso-Tigre, J.; Arevalo, A.; Arancibia, M.; Paucar, M.; Velázquez-Martí, B. Thermal evaluation of a hybrid dryer with solar and geothermal energy for agroindustry application. Appl. Sci. 2019, 9, 4079.
  66. Ivanova Dandonov, K. Analytical and experimental study of combined fruit and vegetable dryer. Energy Convers. Manag. 2001, 42, 975–983.
  67. Sircar, A.; Yadav, K.; Bist, N. Application of Geothermal Water for Food and Crop Drying. Int. J. Innov. Res. Technol. 2021, 8, 2349–6002.
More
© Text is available under the terms and conditions of the Creative Commons Attribution (CC BY) license; additional terms may apply. By using this site, you agree to the Terms and Conditions and Privacy Policy.
Upload a video for this entry
Information
Subjects: Others
Contributors MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register :
Lisete Fernandes
,
Pedro B. Tavares
View Times: 642
Revisions: 3 times (View History)
Update Date: 17 Jan 2024
Table of Contents
    1000/1000
    Hot Most Recent
    Video Production Service
    Feedback