Greenhouses

Facts and figures on saving energy in greenhouses.

Here are some ideas on ways to save fuel in your greenhouse through upgrading equipment and preventive maintenance procedures.

Infrared heat

  • Potential energy savings 30-60%
  • Heat objects and people versus heating the air
  • Clean, efficient, and easy to install

Unit heaters

  • Potential energy savings 10-25%
  • If you are using gravity stack unit heaters with standing pilot lights, you are losing energy every minute of every hour, even when the unit is not running. The newer induced draft unit heaters are proven to save fuel because they stop the flow of flue products out of the flue when they are in the off cycle.
  • Right now, the ultimate unit heater to install uses intermittent pilot, induced draft, and combustion air separation to eliminate outside air infiltration completely.

Boilers

  • Potential energy savings 15-50%
  • New technology in boiler combustion and heat transfer can trim down standby and flue gas losses tremendously.
    With most equipment, the side benefit is that the new equipment pollutes less, as well.

Heat delivery piping

  • Potential energy savings 10-35%
  • There are now many ways to bring hot water into plant production zones. Round steel pipes are still a basic and functional choice. However, new finned aluminum pipes and synthetic rubber or thermoplastic tubing can eliminate as much as 80% of the water volume in a heating system which can save fuel.
  • These products allow the placing and directing of precious heat where it has the greatest effect for optimized plant growth.

Integrated computerized controls

  • Potential energy savings 0-50%
  • Computerized control of the greenhouse will rarely increase fuel costs because a better environment is being created. However, higher costs are the exception, not the rule. Typically, growers are able to immediately see the benefits of this technology in reduced utility costs.
  • Allowing the greenhouse the ability to smartly manage temperatures will help in growing a better crop.
  • Computers can also perform many other functions like irrigation, alarming, and data recording.

Glazings

  • Potential energy savings 15-40%
  • The technology of greenhouse glazing has progressed to the point where a new energy efficient product can be installed on roofs, sides, and endwalls for many years of performance before discoloration or structural instability occur.
  • These products, such as infrared blocking polyethylene and Polycarbonate Structured Sheet (PCSS), can be adapted to almost any surface and will save tremendous fuel compared to most single glazed coverings.

Thermal screening curtain systems

  • Potential energy savings 10-30%
  • Once the heat is in a structure it will stay much longer with the presence of a properly equipped thermal screening system. The most popular fabrics in these systems include integral aluminum strips that reflect heating energy back into the growing environment.
  • These systems are customer designed and provided by several industry manufacturers.
  • These systems save energy and can do much better when installed over a modern heating system.

General tightening and insulation

  • Potential energy savings 10-15%
  • Walk the greenhouse facility and make note of all the places where air exchange occurs, such as tears in poly, laps in endwall coverings, and trim around vents.
  • Consider installing brush strips or weather stripping around doors, look into automatic door operators and cover ventilators when not in use for a long period.
  • Install insulation on heating transport piping and piping in the boiler room.
  • Next time you build, look into below grade perimeter insulation. All this effort and investment will have a much faster payoff with today’s fuel costs.

(Some information contributed by Pacific Coast Nurseryman and Garden Supply Dealer publication.)