School of Mines professors build extreme weather greenhouse to support year round farming

RAPID CITY, S.D. — Not satisfied with the performance of readily available greenhouse on the market, Anu and Rajesh Shende decided to build their own.

Bolstered with a $115,000 United States Department of Agriculture Small Business Innovation Research (USDA-SBIR) grant awarded to Shende LLC, the two South Dakota Mines professors have completed the first prototype of an energy efficient, extreme weather greenhouse that is hoped will someday create the condition needed to grow local crops year round.

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While a traditional greenhouse uses fossil fuels to heat, the Shende’s prototype uses solar energy to heat oil which runs through a maze of pipes both above ground and buried 3 feet deep. That oil heats both the air in the greenhouse and the soil.

“This differs in the way that we can have a much higher temperature maintained and retained within the greenhouse because the air is heated by the solar concentrators, and we can bring in a lot more heat inside the greenhouse because of the heat transfer fluid. And so that’s the major difference between the traditional, conventional greenhouses and this greenhouse,” Anu Shende, Mines Associate Research Professor and owner of Shende LLC, said.

China has had success in off-season crop cultivation with similar solar greenhouses that operate year-round in the coldest areas of the country, Anu said. She received other design motivation from Minnesota.

After a year of construction, the project was completed in March 2024. Since then, humidity and temperature data has been collected through a system of sensors.

Tyler Mathieson/NewsCenter1

The solar collectors have heated the greenhouse to 35 degree when it’s 25 below outside and it can go higher allowing for more tropical conditions. The 75-square-foot planting area is insulated underground with a protective wall, ensuring stable conditions for growth. Clear triple-wall polycarbonate glazing—16 mm thick—maximizes solar gain while providing excellent insulation and hail resistance, according to the Mines press release.

“So the heat exchanger that we built and designed and built that can either bring the heat from outside inside and inside to elevate the soil temperature, but at the same time, if you want, we can take the heat from inside to outside too in case the temperature is too high,” said Rajesh Shende, South Dakota Mines interim department head.

The Shende’s goal is to create a final design that will allow local farmers to produce more variety year round. That would support local growth and reduce the need to transport fruits and vegetables to the area.

While there are still hurdles to a final design, the Shende’s are working through those challenges in anticipation of the second phase.

“I hope it will… We can use this, not just in South Dakota, but all those places in America that have extreme weather and so and I think small farmers will benefit from this, if they grow something all year round, and then they cannot have crops growing in the field. They can keep something on the side growing in this kind of greenhouse, and bring economic benefits to small farmers,” Anu said.

The $115,504 grant funded a greenhouse that uses a compound parabolic solar concentrator fitted with a single-axis solar tracker and an oil heat transfer system to convert solar energy to thermal energy. The solar concentrator was supplied by Environmental Solar Systems, a Massachusetts-based company.

A $33,000 subaward from Shende LLC supported Grant Bauer (MS ChemE 24), who worked on the project while obtaining his master’s degree.

Local contractors Bang-up Construction and Silverback Plumbing helped with the construction of the greenhouse prototype. Shannon Mutschelknaus, owner of Wayward Springs Acres in Aurora, S.D., consulted on the project.

Jerry Steinley has lived in the Black Hills most of his life and calls Rapid City home. He received a degree in Journalism with a minor in Political Science from Metropolitan State University in Denver in 1994.