{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,12]],"date-time":"2025-10-12T00:57:28Z","timestamp":1760230648374,"version":"build-2065373602"},"reference-count":24,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2022,8,3]],"date-time":"2022-08-03T00:00:00Z","timestamp":1659484800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"the National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["11972335"],"award-info":[{"award-number":["11972335"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this paper, a new calibration device for an air flow sensor of the VAV terminal unit is designed. Multi-aperture air outlets are designed to meet the calibration requirements of the air flow sensor in a variety of measurement range. The device can calibrate the air flow sensors of different types of VAV terminal unit by a movable flow rectifier without repeating the design of a different calibration pipeline. The Raspberry PI is used to design the high-performance GUI interface and controlling algorithm to achieve a one-button intelligent calibration. The air flow sensors in three different types of VAV terminal units are used to calibrate the experiment. After testing, the differential pressure value measured by the air flow sensor can accurately measure the air flow within the accuracy of 5% after the formula conversion. The conversion from differential pressure values to air flow values requires precise calibration in order to establish an accurate air flow equation, and here the calibration device plays a key role. The negative effect caused by the distance between the flow rectifiers and the VAV terminal unit is discovered. In other words, the distance between the inlet flow rectifier and the air inlet of VAV terminal unit should be kept as close as possible, or within a range of 2~3 cm. Moreover, the distance between the air outlet of VAV terminal unit and the middle-flow rectifier should be kept as close as possible; otherwise, any slight gap will cause a huge error in the calibration result. The research contributes to the further study of airflow sensing technology through the conversion and calibration of differential pressure measurements to accurate air flow values.<\/jats:p>","DOI":"10.3390\/s22155797","type":"journal-article","created":{"date-parts":[[2022,8,3]],"date-time":"2022-08-03T23:33:01Z","timestamp":1659569581000},"page":"5797","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["A Universal Calibration Device for an Air Flow Sensor of the VAV Terminal Unit"],"prefix":"10.3390","volume":"22","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1539-7683","authenticated-orcid":false,"given":"Heng","family":"Zhang","sequence":"first","affiliation":[{"name":"College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou 310018, China"}]},{"given":"Hui","family":"Cai","sequence":"additional","affiliation":[{"name":"College of Mechanical and Electrical Engineering, China Jiliang University, Hangzhou 310018, China"}]},{"given":"Xin","family":"Zhang","sequence":"additional","affiliation":[{"name":"College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China"}]},{"given":"Wenjian","family":"Cai","sequence":"additional","affiliation":[{"name":"EXQUISITUS, Centre for E-City, School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798, Singapore"}]},{"given":"Zhaoqin","family":"Yin","sequence":"additional","affiliation":[{"name":"College of Metrology and Measurement Engineering, China Jiliang University, Hangzhou 310018, China"}]}],"member":"1968","published-online":{"date-parts":[[2022,8,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"626","DOI":"10.1016\/j.egyr.2021.11.280","article-title":"A review on buildings energy information: Trends, end-uses, fuels and drivers","volume":"8","author":"Coronel","year":"2022","journal-title":"Energy Rep."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1016\/j.apenergy.2012.10.037","article-title":"Achieving better energy-efficient air conditioning\u2014A review of technologies and strategies","volume":"104","author":"Chua","year":"2013","journal-title":"Appl. Energy"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Do, H., and Cetin, K.S. (2019). Data-Driven Evaluation of Residential HVAC System Efficiency Using Energy and Environmental Data. Energies, 12.","DOI":"10.3390\/en12010188"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"574","DOI":"10.1016\/j.apenergy.2018.12.026","article-title":"Modeling, air balancing and optimal pressure set-point selection for the ventilation system with minimized energy consumption","volume":"236","author":"Jing","year":"2019","journal-title":"Appl. Energy"},{"key":"ref_5","unstructured":"Guo, W.Q., and Zhou, M.C. (2009, January 11\u201314). Technologies toward Thermal Comfort-based and Energy-efficient HVAC Systems: A Review. Proceedings of the IEEE International Conference on Systems, Man and Cybernetics, San Antonio, TX, USA."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"108641","DOI":"10.1016\/j.buildenv.2021.108641","article-title":"Experimental study of five different VAV air terminal devices under variable heat gain conditions in simulated office and meeting rooms","volume":"209","author":"Wu","year":"2022","journal-title":"Build. Environ."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"110995","DOI":"10.1016\/j.enbuild.2021.110995","article-title":"What are the impacts on the HVAC system when it provides frequency regulation?\u2014A comprehensive case study with a Multi-Zone variable air volume (VAV) system","volume":"243","author":"Lu","year":"2021","journal-title":"Energy Build."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"108681","DOI":"10.1016\/j.buildenv.2021.108681","article-title":"Predictive modelling and optimization of HVAC systems using neural network and particle swarm optimization algorithm","volume":"209","author":"Afroz","year":"2022","journal-title":"Build. Environ."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"343","DOI":"10.1016\/j.buildenv.2013.11.016","article-title":"Theory and applications of HVAC control systems\u2014A review of model predictive control (MPC)","volume":"72","author":"Afram","year":"2014","journal-title":"Build. Environ."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Kim, H.J., Jo, J.H., and Cho, Y.H. (2019). Development of Virtual Air Flow Sensor Using In-Situ Damper Performance Curve in VAV Terminal Unit. Energies, 12.","DOI":"10.3390\/en12224307"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"111449","DOI":"10.1016\/j.enbuild.2021.111449","article-title":"A study on the sensor calibration method using data-driven prediction in VAV terminal unit","volume":"258","author":"Kim","year":"2022","journal-title":"Energy Build."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.flowmeasinst.2018.10.021","article-title":"Pitot sensor air flow measurement accuracy: Causal modelling and failure risk analysis","volume":"65","author":"Ezzeddine","year":"2019","journal-title":"Flow Meas. Instrum."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"134","DOI":"10.1016\/j.enbuild.2018.06.039","article-title":"An identification method for room temperature dynamic model based on analytical solution in VAV system","volume":"174","author":"Xing","year":"2018","journal-title":"Energy Build."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"566","DOI":"10.1016\/j.applthermaleng.2007.04.011","article-title":"Performance improvement of VAV air conditioning system through feedforward compensation decoupling and genetic algorithm","volume":"28","author":"Wang","year":"2008","journal-title":"Appl. Therm. Eng."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"362","DOI":"10.1016\/j.applthermaleng.2015.05.032","article-title":"In-situ validation of a fault tolerant control strategy for VAV systems","volume":"87","author":"Shan","year":"2015","journal-title":"Appl. Therm. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"192","DOI":"10.1016\/j.jobe.2018.12.005","article-title":"Rule-based fuzzy control method for static pressure reset using improved Mamdani model in VAV systems","volume":"22","author":"Li","year":"2019","journal-title":"J. Build. Eng."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1774","DOI":"10.1016\/j.enbuild.2011.03.018","article-title":"A robust fault detection and diagnosis strategy for pressure-independent VAV terminals of real office buildings","volume":"43","author":"Wang","year":"2011","journal-title":"Energy Build."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"107667","DOI":"10.1016\/j.buildenv.2021.107667","article-title":"Fault detection and diagnosis for multiple faults of VAV terminals using self-adaptive model and layered random forest","volume":"193","author":"Wang","year":"2021","journal-title":"Build. Environ."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"116605","DOI":"10.1016\/j.apenergy.2021.116605","article-title":"A real-time optimal control strategy for multi-zone VAV air-conditioning systems adopting a multi-agent based distributed optimization method","volume":"287","author":"Li","year":"2021","journal-title":"Appl. Energy"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"100839","DOI":"10.1016\/j.jobe.2019.100839","article-title":"Model parameter identification of indoor temperature lag characteristic based on hysteresis relay feedback control in VAV systems","volume":"25","author":"Li","year":"2019","journal-title":"J. Build. Eng."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1016\/j.enbuild.2013.11.005","article-title":"A study on the control method of single duct VAV terminal unit through the determination of proper minimum air flow","volume":"69","author":"Kang","year":"2014","journal-title":"Energy Build."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"109473","DOI":"10.1016\/j.enbuild.2019.109473","article-title":"Occupancy-based zone-level VAV system control implications on thermal comfort, ventilation, indoor air quality and building energy efficiency","volume":"204","author":"Anand","year":"2019","journal-title":"Energy Build."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"81","DOI":"10.1016\/j.buildenv.2013.09.015","article-title":"Improving airflow measurement accuracy in VAV terminal units using flow conditioners","volume":"71","author":"Liu","year":"2014","journal-title":"Build. Environ."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.buildenv.2018.05.014","article-title":"Airflow measurements using averaging Pitot tube under restricted conditions","volume":"139","author":"Cui","year":"2018","journal-title":"Build. Environ."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/15\/5797\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T00:03:43Z","timestamp":1760141023000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/15\/5797"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,3]]},"references-count":24,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["s22155797"],"URL":"https:\/\/doi.org\/10.3390\/s22155797","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2022,8,3]]}}}