Grain Quality

Grain Aeration

GEAPS Online Learning courses are available anytime on-demand. Each course takes approximately 10 hours to complete and can be completed at any pace over five weeks. Courses must be completed within a five-week period that begins the day you register. After registering, learners will be sent a confirmation email, then you’re ready to start learning!  


$495 for members
$795 for non-members.  

Course Description: This course focuses on the design and operation of aeration systems for dry grain storage structures with flat, hopper and V-bottoms in corrugated steel bins, concrete silos, large diameter tanks, horizontal storage structures and outdoor piles/bunkers. The relationship between air and grain properties will be reviewed and the selection and sizing of fans and their operational management for conditioning and cooling grains will be thoroughly discussed. Ideally, students should take Quality Grain Management before taking this course, but it is not a requirement.

Course Goals: The goal of the course is to teach students the basic principles of designing and operating grain aeration systems to successfully maintain grain quality during storage. Students will understand the overall purpose of grain aeration and aeration system components as well as how to calculate and develop strategies for aeration system design and fan operational management. By the end of each lecture students will be able to answer study questions and by the end of the course students will be able to complete a case study on selecting and operating aeration control equipment.

Target Audience: This course is designed for people with responsibilities relating to preservation of grain quality, as well as aeration-equipment operation, design, selection and purchasing. It is intended for facility and systems designers, aeration systems vendors, facility owners and operators, elevator superintendents, location or regional managers, and anyone with a professional need to learn more about aeration system design and efficient fan operation management.


Dr. Dirk Maier  Iowa State UniversitySee Bio

Dr. Maier is professor at Iowa State University and previously served as director of the GEAPS/K-State Distance Education Program. Maier’s research and extension education programs focus on post-harvest engineering, stored-product protection, structural fumigation, value-added processing, and quality assurance of agricultural crops and biological products. Before joining Iowa State University, Dr. Maier was professor and head of the Department of Grain Science and Industry at Kansas State University and professor, associate head and extension agricultural engineer at Purdue University.

Dr. Kenneth Hellevang  North Dakota State UniversitySee Bio

Dr. Hellevang has a Ph.D. in engineering and is a registered professional engineer. As a professor of agricultural and biosystems engineering, he has provided education and technical assistance in crop post harvest, structures and indoor environmental engineering since 1980. He has provided engineering assistance to more than 11,000 people across the United States and internationally, delivered more than 800 educational presentations, and written numerous articles for newspapers, magazines and newsletters

Dr. Ron Noyes  Oklahoma State UniversitySee Bio

Prior to retirement in 2004, Dr. Noyes was an extension agricultural engineer with expertise in the areas of grain drying, storage and handling and agricultural chemical handling and with emphasis on aircraft spray-systems calibration. Noyes is president of Grain Storage Engineering, LLC and works as a consultant in grain storage systems engineering.

Dr. Ricardo Bartosik  National Institute of Agricultural TechnologiesSee Bio

Dr. Bartosik is a researcher and extension engineer for the National Institute of Agricultural Technologies (INTA) of Argentina, serving as national coordinator of post-harvest grain programs. Dr. Bartosik’s research experience includes grain drying, aeration design and management, controlled atmospheres and modeling of the grain ecosystem and grain post-harvest processes. He is also involved in higher education and professional training in post-harvest grain operations.

The Course of Study

Week 1Details

Lecture 1 – Objectives of Aeration and Aeration System Components
The aim of this lecture is to show students the importance of aeration for the purpose of cooling and conditioning stored grains and to review key system components, including fans, transitions, ducts, floors, vents and controls. This lecture will include the following topics: cooling of grain to maintain grain quality and suppress insects, mites and molds; fan types; ideal air velocities; supply and transition ducts, manifolds and elbows; calculating airflow volume through ducts; roof vents; perforated flooring and fan controllers.
Lecturer: Dr. Dirk Maier

Lecture 2 – Relationship Between Air and Grain Properties
This lecture reviews the relationship between air properties (psychrometrics) and grain properties (equilibrium moisture content). It will cover the following topics: basic air properties and psychrometric relationships, grain equilibrium moisture content relationships, determining safe storage moisture contents and using psychrometrics to analyze local and historic weather data.
Lecturer: Dr. Dirk Maier; Contributor, Dr. Ricardo Bartosik

Week 2Details

Lecture 3 – Airflow Rates, Resistance to Airflow and Air Distribution Patterns
This lecture focuses on the relationship between airflow rates and resistance to airflow that occurs with different grain types and depths, and reviews distribution of airflow through peaked, leveled, cored and inverted grain held in storage-structure configurations with flat, hopper and V-bottoms. The lecture will also include the following topics: airflow rates required for cooling and conditioning, airflow cycle time, principles of Shedd’s Equation, the concept of frictional resistance, estimating static pressure drop through grain, estimating pressure drop through aeration system components, pressure patterns, fine material concentration and non-uniform airflow in grain.
Lecturer: Dr. Dirk Maier; Contributor: Dr. Ricardo Bartosik

Lecture 4 – Fan Sizing and Selection
This lecture will discuss the importance of proper fan sizing and selection to achieve desired operational effects. It will have two main topics for discussion: the principles of fan sizing and selection and fan performance characteristics. The lecture will also touch on fan types, sizing, and selection; direction of airflow; fan performance characteristics; and the FANS program. It will utilize the FANS program from the Post-Harvest Handling of Crops website from the University of Minnesota to better understand the FANS program.
Lecturer: Dr. Dirk Maier

Week 3Details

Lecture 5 – Design of Bin/Silo Aeration
This lecture will familiarize students with the engineering calculations and design considerations involved in sizing and implementing the simplest aeration systems. It will discuss aeration floor layouts and system designs for flat and hopper bottom round bins, silos, and tanks; inlet and exhaust roof venting; vent types and characteristics; and vent positioning and supporting.
Lecturer: Dr. Ron Noyes

Lecture 6 – Selecting Ambient Air for the Operation of Aeration Systems
In this lecture students will become familiar with the relationship between ambient air and aeration systems, including the importance of weather analysis. The lecture will cover equilibrium moisture content, fan control strategies, how to evaluate local and historic weather conditions and the effect of weather patterns on aeration effectiveness.
Lecturer: Dr. Dirk Maier

Week 4Details

Lecture 7 – Design and Layout of Aeration Systems: Flat Storage Aeration
This lecture will cover horizontal (flat) storage aeration design criteria, duct length limitations and number of ducts needed. It will also provide examples of each layout and design component of the horizontal storage system.
Lecturer: Dr. Kenneth Hellevang

Lecture 8 – Strategies for Fan Operation to Condition and Aerate Grain
This lecture will go over the considerations involved in operating aeration systems under various climatic conditions. It will review the different operational strategies used to cool and condition grain. It will contain the following topics: operational settings for aeration control systems, aeration cooling to prevent mold development and self-heating, aeration cooling to prevent insect infestation and development, aeration to condition moisture content of stored grain, aeration in upright versus horizontal structures, aeration of outdoor piles and bunkers and warming of winter-cooled grain.
Lecturer: Dr. Dirk Maier

Week 5Details

Lecture 9 – Design and Layout of Aeration Systems in Outdoor Piles and Bunkers
In this lecture students will be familiarized with the engineering calculations and design considerations involved in sizing and laying out the most complex aeration systems. The main topics include: storage types and design criteria, duct length limitations, duct airflow uniformity and placement, grain pile management and bunker design examples.
Lecturer: Dr. Kenneth Hellevang

Lecture 10 – Selecting and Utilizing Aeration Control Equipment
This lecture is designed to acquaint students with the advantages and disadvantages of various aeration controllers. It will cover several topics including: control system components, simple mechanical controllers, complex electromechanical controllers, microprocessor and computer-based controllers, selecting aeration controllers and predicting aeration system performance. It will include a case study on India.
Lecturers: Dr. Dirk Maier, Dr. Ron Noyes