Modeling Greenhouse Efficiency Virtually

Modeling Greenhouse Efficiency Virtually

When you’re comparing structures and coverings, wouldn’t it be great to know which styles and materials will perform best for you before you make a change or start to build? USDA’s free Virtual Grower software program allows you to do that by analyzing the efficiencies of your current structures and constructing models for new ones–all from the comfort of your office.

The idea began in 2003, when plant physiologist Jonathan Frantz joined USDA’s Agriculture Research Service at the University of Toledo in Ohio. His background was in vegetable crops and he started asking local flower growers how they make decisions related to the greenhouse environment–light, temperature and air movement.

With energy efficiency becoming a top concern, Frantz and programmers Bryon Hand and Lee Buckingham set out to develop computer-generated models that would help growers make informed decisions that directly impact energy consumption. The model allows growers to compare styles of structures, the materials they are built from, fuel sources and crop times based on temperature settings and regional climate.

In many ways, this software was developed by growers for growers. “More than 90 percent of what you see in the program has come from grower input and suggestions,” Frantz says. “On the costs page, we have the metrics growers prefer, like cost per square foot and cost per month. They wanted maximum BTUs to help them size boilers appropriately. We’re also working with engineers who have experience doing audits. We execute the ideas given to us.”

In addition to working with the Toledo Area Flower and Vegetable Grower’s Association, Maumee Valley Growers and OFA, Frantz has been collaborating with fellow researchers and faculty members at Michigan State University (MSU), North Carolina State University and Purdue University.

In the “Energy-Efficient Annuals” series we published in Greenhouse Grower, March 2009-February 2010, MSU researchers used Virtual Grower to estimate the cost to heat a half-acre greenhouse to produce each crop for different finish dates at different locations in the United States. This data showed sometimes it is more cost effective and energy efficient to grow plants at warmer temperatures and finish sooner, depending on the regional climate.

“One of the biggest users of Virtual Grower is Erik Runkle at Michigan State,” Frantz says. “He has really done things I wouldn’t think of at all and has probably used the program more than I have. He really pushed what it can do and what to add. He and his students did most of the modeling for different species.”

How It Works

To get started, go to VirtualGrower.net, which is part of USDA’s Agricultural Research Service website, and download the program. When the program is opened, the design page is displayed.

On Virtual Grower’s design page, select your city and state from the drop-down menus. A historical database for weather at that location is loaded, providing typical values of temperature, light and wind speed over the course of 12 months. The weather database from National Renewable Energy Laboratory has information from 230 sites.

The next step is to start building your greenhouse by clicking the “Add New Greenhouse” button. You can then create a simple greenhouse by entering information into the main design page or click on “Advanced Design Options” to create a more detailed greenhouse. Here, you can change the greenhouse’s various dimensions, roof shape and materials.

“You can enter in the new material and test it, or test a new heater or curtain that is not already in the program,” Frantz says. “Once added, you can select the new item from the menu, run a heating schedule and see if the numbers go up or down.”

Virtual Grower can help describe the air exchange rate (leakage or infiltration) for a greenhouse. This allows users to see how small changes in the greenhouse can impact their overall costs. The heating efficiency section allows users to describe overall heat system efficiency based on simple user input. Users can see how changes in the management of a heating system (such as maintenance frequency) can impact overall costs.

The program also allows growers to design complex and realistic heating schedules by clicking on the “Heating Schedules” tab. You can select your greenhouse and click on “Add Schedule” and then customize the schedule to match what you are modeling. Clicking the “Costs” tab will allow you to estimate your fuel costs based on location, fuel, heating schedule and greenhouse design.

The “Plant Growth” section allows growers to grow plants in their virtual greenhouses and see how different heating schedules will impact a plant’s development. Plant size and the time it will take to flower are estimated using light, temperature and CO2 concentrations in the greenhouse.

“A grower can do what-if scenarios in a few minutes, instead of changing systems and then finding out over several weeks or even a whole growing cycle, did I save money or lose it?” Frantz says. “Some of the findings have surprised me, such as the difference between glass and corrugated polycarbonate. Polycarbonate is actually worse than glass for heat retention. And others are counterintuitive, that you can save money by heating up the greenhouses, as was found in some of Runkle’s studies.”

Frantz also has been testing tried-and-true industry standards and rules of thumb. “I tested the rule that for every one degree Fahrenheit you reduce the temperature, you save 3 percent on heat,” he says. “For certain areas, it’s right on. For others, it’s higher or lower. It depends on the structure, too.”

A Work In Progress

The current version or generation of Virtual Grower is 2.5, and 3.0 is on the way. “The next version will be substantially different in appearance and we’re changing computer languages so Mac users and others can use it,” Frantz says. “We’re also going to have more graphics, graphs, interactive maps and pictures of greenhouse buildings, so as you’re building, you can see how things change in real time. In the future, there will be more eye candy and it will be fun to use.”

A Spanish version debuted in February. “This was targeted for the migrant labor force,” Frantz says. “Often times, they are in the greenhouses more than the manager and might know the facility better or more accurately describe and put in realistic numbers. It’s also a training tool for how a greenhouse works versus spending a whole season making mistakes.”

Virtual Grower has been tested and will continue to be tested in a number of commercial greenhouse operations, large and small. One 2.5-acre greenhouse operation in Ohio used it to justify an upgrade to its heating system, increasing efficiency from 60 percent to 80 percent. The operation typically spent $34,000 on propane a year and Virtual Grower and an outside engineer independently estimated the savings to be about $8,000 a year.

Another owner of a half-acre greenhouse in Ohio looked at saving energy by installing inexpensive, temporary side curtains. Most of the facility had single-layered glass walls. Just adding a plastic sheet on the west glass wall to enhance insulation was projected to result in a savings of $300-$400 from $6,000 spent on natural gas.

Another Ohio grower was looking to replace 20 old gravity-vented unit heaters with high-efficiency power-vented models. Upgrading from 60 percent efficiency to 80 percent was projected to save $15,500 off a $60,000 heating bill.

One grower building a new 5-acre gutter-connected facility used the model to compare a biomass heating system with a conventional natural gas-fired system. The model predicted the cost of heating to be about $56,000 per year, compared to the actual operational cost of the biomass heating system over the last two years at $50,000 a year.

In each case study, independent estimates and actual costs were used to verify the Virtual Grower projections. The program proved to be a valuable tool for growers calculating returns on their investments in improvements. Frantz is looking for more grower input and feedback.

For more information about Virtual Grower, visit VirtualGrower.net or contact Jonathan Frantz, USDA Agricultural Research Service, Toledo, Ohio, 567-277-0247, [email protected]

Leave a Reply

More From Finance/Operations...
Pansy ‘Cool Wave Blue Skies’ (Wave)

September 20, 2016

PanAmerican Seed Settles Alleged Trade Sanction Violations

PanAmerican Seed, a division of Ball Horticultural Co., has been charged with violating trade sanctions to Iran over a number of years. According to a release from the U.S. Treasury department, PanAmerican Seed made 48 indirect sales of seeds to two Iranian distributors. The company shipped the seed to consignees based in countries in Europe and the Middle East. PanAmerican Seed’s customers then arranged for the re-exportation of the seeds to Iran. The release states that the Office of Foreign Assets Control (OFAC) determined PanAmerican Seed did not voluntarily self-disclose the alleged violations to OFAC, constituting an egregious case. “We believe that the settlement was extreme; however the alternative was to litigate with the U.S. government, which would take months, if not years,” says Todd Billings, Chief Financial Officer for Ball Horticultural Co. When asked what Ball Horticultural Co. has done to ensure that violations to trade sanctions do not […]

Read More
young-plants

September 20, 2016

The Top Young Plant Growers, And Four Critical Challenges Facing Them

In Greenhouse Grower’s 2016 Top Young Plant Growers Survey, growers discuss the latest challenges and opportunities in fulfillment, shipping, labor, and crop protection.

Read More
Cavicchio Greenhouses

September 6, 2016

Cavicchio Greenhouses Wins Inaugural Sustainability Award

The Sudbury, MA, growing operation sustains more than 250 acres of annuals, perennials, and nursery stock, with a number of practices to mitigate its impact on the environment.

Read More
Latest Stories
Pansy ‘Cool Wave Blue Skies’ (Wave)

September 20, 2016

PanAmerican Seed Settles Alleged Trade Sanction Violati…

PanAmerican Seed, a division of Ball Horticultural Co., has been charged with violating trade sanctions to Iran over a number of years. According to a release from the U.S. Treasury department, PanAmerican Seed made 48 indirect sales of seeds to two Iranian distributors. The company shipped the seed to consignees based in countries in Europe and the Middle East. PanAmerican Seed’s customers then arranged for the re-exportation of the seeds to Iran. The release states that the Office of Foreign Assets Control (OFAC) determined PanAmerican Seed did not voluntarily self-disclose the alleged violations to OFAC, constituting an egregious case. “We believe that the settlement was extreme; however the alternative was to litigate with the U.S. government, which would take months, if not years,” says Todd Billings, Chief Financial Officer for Ball Horticultural Co. When asked what Ball Horticultural Co. has done to ensure that violations to trade sanctions do not […]

Read More
young-plants

September 20, 2016

The Top Young Plant Growers, And Four Critical Challeng…

In Greenhouse Grower’s 2016 Top Young Plant Growers Survey, growers discuss the latest challenges and opportunities in fulfillment, shipping, labor, and crop protection.

Read More
Cavicchio Greenhouses

September 6, 2016

Cavicchio Greenhouses Wins Inaugural Sustainability Awa…

The Sudbury, MA, growing operation sustains more than 250 acres of annuals, perennials, and nursery stock, with a number of practices to mitigate its impact on the environment.

Read More
Charlie Hall Feature Image

September 6, 2016

10 Insights From Charlie Hall’s Green Industry Economic…

With the uncertain current economic climate, Texas A&M economist Charlie Hall says now may be the perfect time to invest — as long as you do it smartly.

Read More
Penn State Plant Bud

August 23, 2016

AmericanHort Is Helping Plant Importers Adjust To New R…

A report from Craig Regelbrugge at AmericanHort says the government is implementing a streamlined system for imports, in which all required data will be submitted electronically through a single window.

Read More
Plug Connection Assortment

August 9, 2016

AmericanHort’s Plug And Cutting Conference Will Feature…

This year’s conference, which takes place Sept. 19-21 in Carlsbad, CA, features discussions on water, pest and disease control, and production inputs, as well as a biocontrols workshop and tour of local cuttings facilities.

Read More
Cannabis In Greenhouse

July 27, 2016

The Top 5 Myths About Cannabis Production Cleared Up

There is a lot of misleading information going around about growing cannabis. Industry insider James Lowe makes sure you know the truth about cannabis production.

Read More
Joe Bischoff

July 26, 2016

SAF Partners With Cornerstone Government Affairs To Adv…

A new partnership between the Society of American Florists (SAF) and Cornerstone Government Affairs ensures that SAF will continue its highly effective work advocating for issues that affect the floriculture industry. “SAF and Cornerstone together provide experienced voices on Capitol Hill to protect our growers’ interests,” says SAF CEO Peter Moran. “We’ll continue to move major policy priorities forward on behalf of small business and agriculture.” Cornerstone is a public affairs firm specializing in government relations, strategic consulting, and advocacy. Its team of more than 50 senior professionals includes former senior professional staff from both authorization and appropriations committees and the U.S. Department of Agriculture (USDA), as well as veterans of the horticulture industry. Agricultural and horticultural issues of primary concern to SAF members include access to labor, immigration, crop protection, international trade and other matters related to the day-to-day operations of growers. Before she retired this year, SAF lobbyist Lin […]

Read More

July 26, 2016

AFE Releases New Videos Highlighting Industry Successes

The American Floral Endowment (AFE) recently released five new videos, created to highlight floriculture successes through industry collaboration, support, and participation. “Each video shares real stories from industry members on career development through scholarships and internships, and true examples of research solutions that have shaped how the industry operates today,” says Laura Shinall, President of Syndicate Sales, Inc., and AFE Public Relations and Development Chair. “We’re excited to be able to share some great success stories in an effort to increase industry participation.” The introductory video “Heard of the American Floral Endowment?” helps educate those who aren’t currently aware of AFE’s programs, while other segmented videos (retail, wholesale, grower) share how Endowment programs complement each group and why it’s so important that everyone in the industry participates: Retail Florists Share Why They Turn to AFE New Resources for Floral Wholesalers and Suppliers AFE Helping Growers Profit Ready for a Career in Floriculture or Horticulture? […]

Read More
Briscoe White, Growers Exchange

July 6, 2016

The Grower’s Exchange Unlocks The Secret to E-Commerce

In the Internet era, Briscoe and Kenan White knew they had to adapt or die and specialize to survive. Here’s how they took The Grower’s Exchange online.

Read More
Brie Arthur

July 6, 2016

5 Can’t-Miss Events To Watch For At Farwest 2016

Whether it’s classes on biocontrols and gardening trends, or networking opportunities in and around the trade show floor, there’s plenty happening at Farwest 2016 in Portland, OR, in August.

Read More
Cannabis states 2016

July 1, 2016

Adult Use Of Cannabis On The Ballot In 2016

25 states have legalized cannabis and public opinion is increasingly positive. Here’s where things may be headed as we move toward the fall elections.

Read More
Practical Software Grower Vertical

June 18, 2016

Practical Software Solutions Increases Accessibility, E…

Practical Software will demonstrate Grower Vertical, its customizable and scalable enterprise management system for the horticulture industry, at Cultivate’16 in July.

Read More
Battlefield Farms Company shot

June 14, 2016

Battlefield Farms Is A Finalist For 2016 Operation Of T…

Battlefield Farms in Rapidan, VA, is one of three finalists for Greenhouse Grower’s 2016 Operation Of The Year award and winner of the Excellence In Innovation award for 2016.

Read More

June 7, 2016

Ball Seed Offers Full Mobile Ordering Capabilities With…

The latest update for Ball Seed’s WebTrack To Go mobile app now includes full ordering capabilities for the industry’s largest assortment of seeds and plants. App users can also complete order fulfillment via seed count or package size, find product substitutions, get personalized “contact us” information, request plant tags, and more. “Upgrading WebTrack To Go to the full suite of ordering and management tools is where we’ve always wanted to be,” says Mark Morris, Director of IT for Ball Seed. “With this new roll-out, we’re keeping up with our customers on-the-go and providing them the information and access they need –- even while away from their desks.” The Ball Seed WebTrack To Go app lets customers: Check order status and shipment tracking 24-7 Access up-to-the-minute product inventory from hundreds of suppliers Place orders by seed count, packet size, and more Find product info, culture and photos when and where they […]

Read More
Gotham Greens Atrium Style Greenhouse Chicago

May 23, 2016

What’s Good For The Environment Is Good For Business [O…

Investing in technology to become more sustainable “always goes hand in hand,” says Abe VanWingerden, co-CEO of Metrolina Greenhouses. “If it is good for the environment, it normally is good for business over the long term.” That connection was abundantly clear in the responses we received to this year’s Top 100 Growers Survey. VanWingerden points to three investments Metrolina has made as good examples of how technology can reduce an operation’s carbon footprint and pay dividends financially. Its biomass system burns locally sourced waste wood — a renewable resource; its ozone water treatment system cleans irrigation water, reducing the need for fertilizers and pesticides, and improving plant quality and precision growing; and electrostatic sprayers reduce water and chemical use, and provide more targeted chemical applications. Other Top 100 Growers have found VanWingerden’s theory to be true, as well. Costa Farms’ investment in solar energy panels on three buildings at its […]

Read More
Petunia 'Supertunia Violet Star Charm' (2015 University of Georgia Field Trials)

May 10, 2016

New Southern-Centric Ornamental Production Conference T…

The 2016 Academy of Crop Production is dedicated exclusively to sharing information on advanced ornamental crop production and business management techniques for ornamental producers.

Read More
University of Florida Online Greenhouse Training Courses

April 25, 2016

University of Florida Offering Online Training Courses …

There will be five courses offered, with the first starting on May 30. Courses are available in both English and Spanish and range from beginner level to advanced education.

Read More
[gravityform id="35" title="false" description="false"]