4 Ways Bench Heat Saves Energy
Grow healthier plants and increase efficiency with a radiant bench heating system.

by Michael Kovalycsik, National Sales & Marketing Director, Delta T Solutions

 

Tubing is spaced 2 to 3 inches apart on the SD rubber tube bench system, which heats starting at the soil and roots, ideal for germination.
Hot water runs through the fin tube in the DELTA-FIN TF2 under-bench system to efficiently heat the surrounding air, distributing warmth to the soil, roots and foliage.

Growers are always looking for ways to maximize efficiency and cut costs through sustainable growing practices. Using radiant bench heat is just one way to accomplish all these goals and benefit your bottom line.

In the case of hydronic bench heat, water is circulated through tubes installed on top of or under the bench mesh. This method of heating is highly efficient because it heats the plants starting at the soil level rather than the air in the greenhouse. This results not only in accelerated rooting and plant growth, but energy savings, as well – as much as 20 to 30 percent fuel savings over conventional forced air heating.

Hydronic bench heating has numerous benefits. “The plants are sitting directly on the surface that’s heated, so you get root zone heating as opposed to a lot of air heating,” says Joyce Latimer, Virginia Tech professor and Extension specialist for greenhouse crops in Virginia. “So typically, you’ll have a more efficient system, and you’ll have a healthier plant because the root zone is warmed to allow root growth.”

Latimer adds that in plug or seedling production, warming the media improves the speed of germination and oftentimes percent germination. “Any time you can optimize the temperature of the soil, you’re going to optimize germination and therefore get faster and better germination with fewer seed or seedling losses,” she says. In addition, it will help dry the soil to reduce fungal issues.

TWO BENCH HEATING OPTIONS
Delta T Solutions offers two types of bench heating systems, which provide even soil temperature throughout – the DELTA-TUBE™ EPDM SD rubber tube bench system and the DELTA-FIN™ TF2 aluminum under-bench system.

 

4 Benefits of Radiant Bench Heat

1. Faster Turns. Heats the roots at the soil level for healthier plants and faster turns.

2. Energy Efficiency. Air temperature in the greenhouse can be lower when root zones are being heated. This results in less heat loss.

3. Flexible Fuel Sources. Boilers can be fueled with natural gas, oil and liquid propane or in some cases wood fired or biomass.

4. Less water and disease. This means more benefits for the plants themselves.

The SD rubber tube bench system includes tubing spaced 2 to 3 inches apart, heating the plants starting at the soil and roots. The small tube design reduces water volume, making the system quick and efficient. It’s also a low water temperature system, requiring a water temperature of 135°F.

The DELTA-FIN TF2 aluminum under-bench heating system heats the plants with the hot water that runs through the fin tube system. The fin tube heats the surrounding air and distributes warmth to the soil, roots and foliage through natural convection and radiant heat. This system uses water temperatures from 160°F to 230°F.

REBUILDING WITH ENERGY EFFICIENCY IN MIND

Pam Snodgrass, president of P & D Nursery in Tualatin, OR, says that after P & D’s original propagation house collapsed under snow, she knew she wanted to rebuild in the most energy-efficient way she could. That’s why she chose radiant bench heating. However, she found that efficiency wasn’t the only advantage. “The biggest benefit is that the cuttings tend to root faster,” she says. “It’s a faster turn.” Plus, she adds, the cuttings tend to get a little more attention from employees when they’re at eye level rather than on the ground.

 

Tubing is spaced 2 to 3 inches apart on the SD rubber tube bench system, which heats starting at the soil and roots, ideal for germination.
Tubing is spaced 2 to 3 inches apart on the SD rubber tube bench system, which heats starting at the soil and roots, ideal for germination.

 

 

“Always work with a reputable company. Make sure that if they’re using a separate boiler for this that they’re sizing that correctly based on how much water they’re moving and the temperature they’re trying to maintain.”


– Dr. Joyce Latimer, Virginia Tech Extension specialist for greenhouse crops

 

If you do install a bench heat system Snodgrass recommends making sure your tubing is insulated so you don’t lose energy through the bottom of the bench. “Or [you can put a] black plastic curtain around the bench so the heat stays in instead of going outside into the rest of the house and eventually heating the air,” she says.

While some growers might be concerned about the cost of installing a radiant bench heat system, Snodgrass notes that the payback comes quickly, both in the energy savings and faster turns. “It was definitely worth it,” she says.

Delta T Solutions has developed customized and affordable bench heating for growers across the U.S. To learn more about how bench heating can improve your operation, contact Delta T Solutions at 800-552-5058 or email info@deltatsolutions.com.


 

 
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