Collaborative Design of Photovoltaic-Powered Ventilation for Deep Winter Greenhouses in the North Central Region Using Computational Fluid Dynamics

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Collaborative Design of Photovoltaic-Powered Ventilation for Deep Winter Greenhouses in the North Central Region Using Computational Fluid Dynamics (CFD)

Deep Winter Greenhouses (DWGs), developed by the University of Minnesota, are climate-adapted structures designed to extend the growing season in cold regions. Their design incorporates an angled south-facing glazing wall that captures solar radiation and a subsurface rock bed that stores thermal energy during the day and releases it at night. This design supports continuous winter crop production while minimizing reliance on conventional heating sources.

Deep Winter Greenhouses (DWGs) are gaining popularity in Minnesota due to their sustainable design, which not only supports winter crop production but also attracts agrotourism by engaging visitors interested in local food systems and year-round farming practices. However, the south-facing passive solar wall causes excessive heat buildup in the summer, which limits the usability of DWGs for growing warm-season crops.

This study aims to develop and evaluate a photovoltaic (PV)-powered ventilation system as a sustainable solution for managing temperatures in DWGs throughout the year, with a focus on three NC states: Minnesota, Wisconsin, and Illinois. In this study, computational fluid dynamics (CFD) simulations will be used to assess airflow and temperature distributions under both winter and summer conditions. The simulations will be validated using a full-scale DWG located in Lake City, Minnesota. The System Advisor Model (SAM) will be applied to estimate energy generation and assess the economic feasibility of integrating PV-powered ventilation by calculating monthly energy generation, levelized cost of energy, net present value, and payback period.

The project will be conducted in collaboration with a DWG owner who has expressed a willingness to adopt the design developed during the course of the study. Educational materials, including fact sheets, webinars, and podcasts, will be developed and distributed through Extension networks in Minnesota, Wisconsin, and Illinois to facilitate broader adoption.

As a result of this study, growers will gain knowledge of DWGs, seasonal crop strategies, PV-powered ventilation, and available solar incentives. At least one, and potentially up to five, growers will adopt the PV-powered ventilation system. The project will support the expanded adoption of DWGs in Wisconsin and Illinois (two neighboring states to Minnesota) through Extension and outreach efforts. In the long term, the project will support local food production systems, reduce energy use in greenhouse operations, and foster greater interest in renewable energy technologies. Outcomes will be evaluated through surveys, grower engagement, and web analytics.

This project targets Deep Winter
Greenhouse (DWG) owners in the North Central (NC) region.

Learning Outcomes:

• Growers will gain practical
  knowledge of how PV-powered ventilation systems can regulate
  temperatures in DWGs throughout the year.

• Guidelines will be provided on
  fan sizing, placement, PV modules and inverters, and renewable
  energy incentives available in Minnesota, Wisconsin, and
  Illinois.

• Participants will also gain
  practical insights into crop selection based on seasonal
  variations.

Action Outcomes:

• At least one grower, and likely
  up to five, will install PV-powered ventilation systems based on
  the project's design recommendations.

• The project will increase the
  number of growers using DWGs year-round, reducing seasonal downtime
  and improving return on infrastructure investment.

• While DWGs are well
  established in Minnesota, this study will support their expanded
  promotion and adoption in Wisconsin and Illinois.

• Through Extension networks,
  recommendations are expected to reach more than 100 additional
  growers across Minnesota, Wisconsin, and Illinois within one year
  of project completion.

Broader Impact:

• Long-term outcomes include
  improved regional food resilience and greater interest in renewable
  technologies for controlled-environment agriculture.

All these outcomes
will be assessed through pre- and post-surveys, on-site
discussions, and evaluations conducted at Extension and outreach
events (e.g., webinars).