Our 50-acre operation started in 2011 when we moved from Brookings, SD to rural Brookings county after living in town for several years following college. My wife and I both grew up in farming families and desired to raise our children in a similar environment.
Our small operation consists of 30 acres of pasture and 20 acres of grass hay ground. We started off raising Boer meat goats in 2012. We eventually added Jacob sheep and Scottish Highland cattle. In 2018 we started transitioning out of our meat goats in favor of the hardier Jacob sheep and Highland cattle breeds that thrive in our climate with minimal supplemental grain. We currently have 25 sheep and 10 cattle, with a few goats that we’re feeding out.
My primary occupation is mechanical engineering. I have worked for Daktronics, Inc for 16 years, initially designing large industrial cooling systems for our electronic display systems installed across the world. I enjoy computer modeling of advanced customized heating/cooling systems as well as solar heat load simulations for our electronic display systems. I have continued to specialize in product research and testing while currently managing our 15-person testing laboratory. In addition, I contribute to international standards committees and present at industry conferences regarding research.
Growing up I spent summers working for the Hutchinson, Brule, and Buffalo County conservation districts planting, cultivating, and caring for trees. Through this I developed an interest in horticulture, pursuing it primarily as a hobby. While traveling for work and vacation, I developed an interest in the wide range of fruit that is unheard of in our northern climate.
I started saving seeds and soon started so many tropical and sub-tropical trees that I didn’t know what to do with them. While seeking a market, I discovered the demand for exotic tropical fruit trees was robust because they are regularly ravaged by seasonal hurricanes. Examples of the many plants I’ve successfully propagated include soursop, mamey, Garcinia humilus, Garcinio madruno, cherimoya, Monstera deliciosa, passion fruit, etc.
This project allows me to combine my engineering and research expertise with my horticultural experience and exotic plant business. The goal is to develop cost effective and sustainable growing environments, enabling alternative niche crops locally in South Dakota. One day I would like to grow year-round produce that cannot otherwise be grown locally, to meet the demand of our local international student population.
Cold northern climates prevent year-round crop production and make greenhouses too costly for tropical produce. This results in long distance shipping of fruits and vegetables from central America and prevents many types of delicate produce from being available in local markets.
The proposed research will produce data regarding design trade-offs of multiple passive solar greenhouse features as well as demonstration of a selected design. Low cost/high efficiency greenhouse technology could transform our energy intensive food supply chain to a lower cost, more diverse and sustainable system that will improve quality of life for producers and consumers in northern climates.
Unique aspects of this project include:
- Application of advanced mechanical engineering tools typically reserved for high-cost aerospace and medical industries to northern greenhouse designs.
- A focus on year-round production vs. season extension.
- A demonstration site eight miles from South Dakota’s largest agricultural university.
- A naturally sustainable gravity fed spring water source for crop production.
The construction of this highly efficient, cost minimizing greenhouse will allow further development of an exotic plant and fruit horticultural business and expansion into local produce business.
Primary objective: Minimize total cost of greenhouse ownership to enable sustainable production of tropical plants and produce.
- Research, design and simulate multiple in-ground heat storage configurations to maximize heat storage while minimizing electricity usage.
- Minimize summer cooling costs through a fully passive natural convection cooling system.
- Design and construct gravity fed spring water supply system.
- Construct the proposed greenhouse design based on simulation results.
- Monitor key performance parameters and compare to design simulation results.
- Share findings through Year-Round Greenhouse Facebook group, Wayward Springs Farm Web-page, conference presentations, local college classroom presentations as well as public open-house tours.
Design analysis and calculations will be performed utilizing open sourced SimScale CFD (Computational Fluid Dynamics) software and the free Therm 7.6 software for 2D simulations published by Berkeley Lab. Many other tools and references will be utilized such as Microsoft Excel for calculations, PTC Creo for CAD modeling, engineering manuals and prior research by others.
The key elements of the passive solar greenhouse will consist of:
- 28×16′ greenhouse orientated east-west. This allows the south facing walls and roof to be glazed allowing maximum solar heat capture during the coldest months. North wall and roof will be insulated to minimize winter heat loss and maintain cooler temperatures during the hottest summertime months with minimal energy costs for both seasons.
- A soil based in-ground heat storage system to provide the most cost-effective method for heat storage to stabilize daily temperature fluctuations. Main features: insulated 4′ deep concrete foundation, 2-layers of 4″ drain tile arrays in the soil for the air-to-soil heat exchanger, in-line duct fans for air circulation.
- The southern knee wall and roof peak will have openable windows to allow free natural convection cooling during the hottest summer months.
- Multiple wall materials for the north facing structure will be analyzed, such as sustainable straw bale construction or other passive house technologies.
- The southern wall/roof will have triple walled polycarbonate glazing to allow maximum light penetration and minimal heat loss. It will be supported by arched aluminum truss-work.
- I will install a gravity fed water supply system that utilizes local spring water for growing.
After construction, on-going performance of the system will be monitored via:
- Temperature loggers buried in the soil to monitor thermal storage capacity and charge/discharge rates.
- Air temperature loggers to monitor resulting growing conditions
- Electrical current monitoring of the fan circulation system to track energy usage.
Educational & Outreach Activities
SDSU Ag Student Tour:
One faculty and 5 students interested in passive solar greenhouses and year-round production toured the greenhouse January 23rd. Information was communicated via verbally, by email and text with some additional followup afterwards. This was an early tour prior to having much data collected. We are planning tours again later after more time and information are available, and will potentially teach a class on the topic in the spring or fall semester.
Gave two individuals a tour Feb. 15th showing the structure, function of the system and discussing pros/cons of many various designs and materials used in this structure and other various configurations. They are interested in building a system like this near Mission Hill South Dakota. They found out by word of mouth and then Facebook.
Poster Presentation for MOSES Conference:
I will be doing a poster presentation Feb. 27 and 28th to attendees to Midwest Organic & Sustainable Education Service (MOSES) Conference. The audience will be a diverse cross-section from academia to farm operators and students. See attached poster.
Regular Facebook Project posts:
I’ve been posting updates, photos and discussion on the Deep Winter Greenhouse group on Facebook as well as my Wayward Springs Farm page to cover a wide variety of interested persons.
Initial engineering simulations and construction of the project was completed during 2019. This included extensive characterization of 6+ configurations for insulating the foundation/climate battery storage system as well as the airflow characteristics through the heat exchanger system. The results of this will be published after enough data is collected to verify the simulations and feed into the longer term cost/Return on investment calculations.
I began tracking greenhouse performance parameters December 1st 2019 prior to completing insulation and the climate battery heat storage system. This allowed good characterization of the structure’s performance without the climate battery system in place. In best case situation the structure would cool within 10 degrees F of outdoor temperatures by morning time and heat up to 110 degrees F internally on sunny days even in the short hours of daylight in December as expected highlighting the need for a heat storage and supply system to temper these extremes.
As of January 1st 2020 I had the circulation fans for the heat exchanger of the climate battery operating with all of the data acquisition equipment in place. This was delayed past my original plan of fall operation due to our record wet 2019 which slowed construction as well as difficulty obtaining the mineral wool insulation in a reasonable time. However, this ended up being positive because I was able to collect performance data in a near worst case situation of no stored heat from the fall/summer and a record cloudy January of 2020 which gave very little opportunity to store daytime energy for night time usage. Performance was still very good with inside temperatures only falling below 32 degrees F on three occasions when outdoor temperatures fell below -15 degrees F.
Weather patterns changed significantly in February with more sunshine, but colder outdoor weather. The change in number of sunny days far outweighed the colder February temperatures. To date the greenhouse has not experienced any days below 32 degrees F inside during February even with an outside low of -24 degrees F!
It appears as though some of the radishes I seeded on Jan. 10th will be ready to harvest by the end of February! Some other experimental plants like lettuce seeded at the same time are doing well and not far from a first harvest. Some other “sacrificial” plants were added in January such as a purple passion fruit vine (Passiflora edulis) and dwarf banana. The banana did not survive the January frosts. The passion fruit had some damage, but wasn’t killed.
On January 26th, I moved a cherimoya (Annona cherimola) and a soursop (Annona muricata) to the greenhouse. The cherimoya is a subtropical plant and has been thriving in the climate since then. The soursop is a true tropical and dropped leaves when temperatures fell below 45 degrees F early on. However, it is showing budding and new leaf formation by the end of February.
A more detailed report on performance and recommendations will be available on the final report as more data is acquired throughout the year, but preliminary updates will be available via Facebook groups and the farm page.