{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,22]],"date-time":"2026-01-22T07:30:02Z","timestamp":1769067002503,"version":"3.49.0"},"reference-count":25,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2024,12,22]],"date-time":"2024-12-22T00:00:00Z","timestamp":1734825600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"unda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia (FCT) C-MAST (Centre for Mechanical and Aerospace Science and Technologies)","award":["UIDB\/00151\/2020"],"award-info":[{"award-number":["UIDB\/00151\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>This article presents the development of a resistive frost-detection sensor fabricated using Fused Filament Fabrication (FFF) with a conductive filament. This sensor was designed to enhance demand-defrost control in industrial refrigeration systems. Frost accumulation on evaporator surfaces blocks airflow and creates a thermal insulating barrier that reduces heat exchange efficiency, increasing energy consumption and operational costs. Traditional timed defrosting control methods can mitigate these effects but often lead to inefficiencies due to their inability to align with actual frost accumulation, which can vary according to system and environmental conditions. Frost-detection sensors aim to solve this problem by acting as a tool to support defrosting control. A series of tests were conducted to evaluate the sensor\u2019s performance in detecting frost under controlled conditions on a heat exchanger (HX). The sensor reliably detected frost in all cases, demonstrating its effectiveness in real-time frost detection. The sensor measurements were validated by comparison with results obtained through a computer vision method, confirming its reliability. It was also found that the sensor can detect temperature changes. This advancement in sensor technology highlights the potential of additive manufacturing to provide cost-effective, customizable, replicable, and compact sensor designs, contributing to improved system performance and energy efficiency in refrigeration systems.<\/jats:p>","DOI":"10.3390\/s24248193","type":"journal-article","created":{"date-parts":[[2024,12,23]],"date-time":"2024-12-23T10:58:55Z","timestamp":1734951535000},"page":"8193","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Additive Manufacturing of a Frost-Detection Resistive Sensor for Optimizing Demand Defrost in Refrigeration Systems"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0672-0378","authenticated-orcid":false,"given":"Martim Lima de","family":"Aguiar","sequence":"first","affiliation":[{"name":"Department of Electromechanical Engineering, University of Beira Interior, Rua Marqu\u00eas d\u2019\u00c1vila e Bolama, 6201-001 Covilh\u00e3, Portugal"},{"name":"C-MAST\u2014Center for Mechanical and Aerospace Science and Technologies, 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1691-1709","authenticated-orcid":false,"given":"Pedro Dinis","family":"Gaspar","sequence":"additional","affiliation":[{"name":"Department of Electromechanical Engineering, University of Beira Interior, Rua Marqu\u00eas d\u2019\u00c1vila e Bolama, 6201-001 Covilh\u00e3, Portugal"},{"name":"C-MAST\u2014Center for Mechanical and Aerospace Science and Technologies, 6201-001 Covilh\u00e3, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2204-3397","authenticated-orcid":false,"given":"Pedro Dinho da","family":"Silva","sequence":"additional","affiliation":[{"name":"Department of Electromechanical Engineering, University of Beira Interior, Rua Marqu\u00eas d\u2019\u00c1vila e Bolama, 6201-001 Covilh\u00e3, Portugal"},{"name":"C-MAST\u2014Center for Mechanical and Aerospace Science and Technologies, 6201-001 Covilh\u00e3, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2024,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1880","DOI":"10.4028\/www.scientific.net\/AMM.675-677.1880","article-title":"Specific electrical energy consumption and CO2 emissions assessment of agrifood industries in the central region of Portugal","volume":"675\u2013677","author":"Silva","year":"2014","journal-title":"Appl. Mech. Mater."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"763","DOI":"10.2495\/ESUS140681","article-title":"Characterization of the specific energy consumption of electricity in the Portuguese sausage industry","volume":"186","author":"Nunes","year":"2014","journal-title":"WIT Trans. Ecol. Environ."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"393","DOI":"10.1016\/j.rser.2015.12.019","article-title":"Key points on the energy sustainable development of the food industry\u2014Case study of the Portuguese sausages industry","volume":"57","author":"Nunes","year":"2016","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"878","DOI":"10.4028\/www.scientific.net\/AMM.590.878","article-title":"Characterization of the specific electrical energy consumption of agrifood industries in the central region of Portugal","volume":"590","author":"Gaspar","year":"2014","journal-title":"Appl. Mech. Mater."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1013","DOI":"10.1016\/j.applthermaleng.2010.11.006","article-title":"Experimental Study of Frost Accumulation on Fan-Supplied Tube-Fin Evaporators","volume":"31","author":"Silva","year":"2011","journal-title":"Appl. Therm. Eng."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1549","DOI":"10.1016\/j.apenergy.2010.11.006","article-title":"Experimental Investigation of Frost Formation on a Parallel Flow Evaporator","volume":"88","author":"Wu","year":"2011","journal-title":"Appl. Energy"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1016\/j.apenergy.2015.02.071","article-title":"Determination Method of Defrosting Start-Time Based on Temperature Measurements","volume":"146","author":"Kim","year":"2015","journal-title":"Appl. Energy"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1016\/0140-7007(84)90051-3","article-title":"Optimal defrost cycle for the air cooler","volume":"7","author":"Zakrzewski","year":"1984","journal-title":"Int. J. Refrig."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.ijrefrig.2018.02.009","article-title":"Optimal defrost cycle for air coolers revisited: A study of fan-supplied tube-fin evaporators","volume":"89","author":"Hermes","year":"2018","journal-title":"Int. J. Refrig."},{"key":"ref_10","unstructured":"Datta, D., and Tassou, S. (2002). Implementation of a defrost on demand control strategy on a retail display cabinet. Proc. Urbana-Champaign int. Conf. IIR., 218\u2013226."},{"key":"ref_11","unstructured":"Aguiar, M.L., Gaspar, P., and Silva, P.D. (2019). Frost Measuring and Prediction Systems for Demand Defrost Control. Novel Technologies and Systems for Food Preservation, IGI Global."},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Zhang, L.-H., Zhang, J., Li, H.-W., and Hu, Q. (2012, January 21\u201325). The Research of Optical Fiber Frost Sensor and Intelligent Refrigerator Defrost System. Proceedings of the 2012 IEEE 11th International Conference on Signal Processing, Beijing, China.","DOI":"10.1109\/ICoSP.2012.6492017"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"125377","DOI":"10.1016\/j.ijheatmasstransfer.2024.125377","article-title":"Capacitive sensing of frost growth dynamics on aluminum surfaces with different wettabilities","volume":"225","author":"Inanlu","year":"2024","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"118968","DOI":"10.1016\/j.ijheatmasstransfer.2019.118968","article-title":"Condensation frosting detection and characterization using a capacitance sensing approach","volume":"147","author":"Shen","year":"2020","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"124650","DOI":"10.1016\/j.ijheatmasstransfer.2023.124650","article-title":"Detection of frost growth and distribution on louver and offset strip fins of a microchannel heat exchanger using capacitance sensing approach","volume":"217","author":"Shen","year":"2023","journal-title":"Int. J. Heat Mass Transf."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"390","DOI":"10.1111\/j.1749-6632.1965.tb45405.x","article-title":"Mechanism of the electrical conductivity in ice","volume":"125","author":"Jaccard","year":"1965","journal-title":"Ann. N. Y. Acad. Sci."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"263","DOI":"10.1016\/j.egyr.2020.11.258","article-title":"Medium materials for improving frost detection on a resistive sensor","volume":"6","author":"Aguiar","year":"2020","journal-title":"Energy Rep."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"10437","DOI":"10.1109\/JSEN.2022.3168931","article-title":"Fully FFF-printed capacitive displacement sensor based on graphene\/PLA composite and thermoplastic elastomer filaments","volume":"22","author":"Stefanov","year":"2022","journal-title":"IEEE Sens. J."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Masarra, N., Batistella, M., Quantin, J., Regazzi, A., Pucci, M., El Hage, R., and Lopez-Cuesta, J. (2022). Fabrication of PLA\/PCL\/Graphene Nanoplatelet (GNP) electrically conductive circuit using the fused filament fabrication (FFF) 3D printing technique. Materials, 15.","DOI":"10.3390\/ma15030762"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Ragolia, M.A., Di Nisio, A., Lanzolla, A.M., Percoco, G., Scarpetta, M., and Stano, G. (2021, January 17\u201320). Thermal Characterization of Electrical Resistance of 3D Printed Sensors. Proceedings of the 2021 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), Glasgow, UK.","DOI":"10.1109\/I2MTC50364.2021.9459968"},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Stano, G., Nisio, A., Lanzolla, A., Ragolia, M., and Percoco, G. (2021). Fused filament fabrication, a new fabrication paradigm for 3D printing capacitive sensors: Design, fabrication, and characterization for liquid level measurements. Res. Sq.","DOI":"10.21203\/rs.3.rs-875418\/v1"},{"key":"ref_22","first-page":"015005","article-title":"Creating 3D printed sensor systems with conductive composites","volume":"30","author":"Lazarus","year":"2020","journal-title":"Smart Mater. Struct."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Srdic, B., Stefanov, A., Kisi\u0107, M., Zivanov, L., and Menicanin, A. (2021, January 5\u20139). Design and modelling of 3D printed capacitive displacement sensor. Proceedings of the 2021 44th International Spring Seminar on Electronics Technology (ISSE), Bautzen, Germany.","DOI":"10.1109\/ISSE51996.2021.9467666"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"234","DOI":"10.1016\/j.egyr.2022.01.049","article-title":"Image recognition method for frost sensing applications","volume":"8","author":"Aguiar","year":"2022","journal-title":"Energy Rep."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Rodriguez, A., Fuertes, J.P., Oval, A., and Perez-Artieda, G. (2023). Experimental measurement of the thermal conductivity of fused deposition modeling materials with a DTC-25 conductivity meter. Materials, 16.","DOI":"10.20944\/preprints202310.1664.v1"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/24\/8193\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T16:57:50Z","timestamp":1760115470000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/24\/24\/8193"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2024,12,22]]},"references-count":25,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2024,12]]}},"alternative-id":["s24248193"],"URL":"https:\/\/doi.org\/10.3390\/s24248193","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,12,22]]}}}