Session: 17-01-01: Research Posters

Paper Number: 150546

150546 - A Thermal System to Assess Impact of Extreme Heat on Potato Canopies 

Environmental heat stress in potatoes, originating from erratic heat events, can cause yield reductions, malformed tubers, and a loss in postharvest quality that threatens food security. Therefore, it is critical that growers have new knowledge and tools to address these challenges as they arise. As part of a broader effort to assess in-season heat stress and it impacts on plant phenotype, yield, and postharvest quality, we designed, developed and assessed a thermal management system to simulate sustained elevated temperatures around a potato canopy in the natural production environment.

A computational fluid mechanics model, in conjunction with measurements on a prototype, was employed to develop and design a heat box that is 50 inches tall, 59 inches long, and 35 inches wide. The heat box, placed around potato canopy at various stages of growth, is intended to maintain a five-degree Celsius difference in temperature between the inside of the box and the ambient environment through circulation of heated air. Additionally, the box aims to mimic standard growth practices in the field by lacking a roof. Due to this setup, rainwater and water from the sprinkler pivot as well as sunlight can enter the box naturally and unfiltered. The system should run for the duration of the growing season in which potato tubers are developing. The iterative design to reduce the running energy costs while maintaining the desired elevated temperature resulted in a box with slots at two ends to supply heated air to the inside of the box through a recirculating external system. The box has an aluminum profile frame housing four quarter inch, clear acrylic panels. The aluminum frame is effective in maintaining a solid structure when the box may experience up to 20 mph winds.

Three inline duct fans, each 120V/0.3A rated, and two nichrome wire resistance heating elements rated for 240V/4700W and wired in parallel are used to generate and flow heated air through an insulated duct path.  The heat system supplies heated air through a slot in one of the panels and pulls air out of an opposing side of the box. This method intends to reduce the required energy input to heat the air. The heating elements were run at a range of 70V-120V or 1400W-2400W.

One of the most challenging aspects was to minimize the mixing of the ambient air with the air inside the enclosure, in order to keep the heating costs minimal. To achieve this, a novel design utilizing an air curtain was developed. The air-curtain is effective in generating a uniform temperature distribution. Ten high speed 120mm square 3A/12V DC fans set at 250 CFM/5500 RPM were installed to blow a sheet of air across the top of the box and into the inside flat face of the opposing wall of the box.

A controls system was built and programmed and was installed along with weather-proofing material on the ducting. The controls system, comprising a variable transformer (variac), power supply and Arduino connected to the thermocouple sensors, was assembled and contained in a weather-proof box. Four sets of complete heating systems with the above components were deployed in the field. The heat boxes were run for extended time to gather temperature data and to observe the impact of heating on the potato canopy at various stages of growth. The initial temperature measurements indicate an elevated temperature inside the box is achieve through the duration of operation during the day and at night. Long duration measurements were recorded and analyzed to determine the effectiveness of the heat box in maintaining an elevated temperature. These temperature measurements were valuable in optimizing the configuration of the heat box.

Comparison of the post-harvest assessment of the quality of potato tubers subjected to the elevated temperature in the box, compared with those grown in environmental conditions as well as inside a heat box with unheated airflow, lends important insights on the impact of elevated temperature on potato tubers.

 

Presenting Author: Soumik Banerjee Washington State University

Presenting Author Biography: Dr. Banerjee is an Associate Professor in the School of Mechanical and Materials Engineering (MME) at Washington State University and currently serves as the Graduate Program Chair at the School of Mechanical and Materials Engineering. He also serves as an Associate Editor of the Journal of Electrochemical Energy Conversion and Storage as well as on the editorial board for Computational Thermal Sciences. Dr. Banerjee’s research expertise lies in modeling of processing, structure and functional properties of materials and interfaces relevant to energy conversion and storage. Dr. Banerjee routinely employs ab initio quantum mechanical calculations, atomistic and molecular modeling techniques, as well as stochastic models such as kinetic Monte Carlo to simulate a range of materials including electronic materials, ceramics, hybrid perovskites, sulfide glasses, and ionic liquids. Dr. Banerjee is an elected Fellow of the American Society of Mechanical Engineers (ASME) and has received several prestigious awards including the 3M Non-tenured Faculty Award in 2013 and the Pratt Fellowship at Virginia Tech. He has published over 50 peer-reviewed articles and presented more than 50 times at national and international meetings. Dr. Banerjee’s work has been widely cited by others and his scholarly work has an h-index of 20 and i-10 index of 28. Dr. Banerjee has been active in his scientific community and has organized symposia, topics and sessions at several conferences.

Authors:

Max Saviello Washington State University
Tyler Akana Washington State University
Mark Pavek Washington State University
Jacob Blauer Washington State University
Soumik Banerjee Washington State University