Published Apr 17, 2015

PFI On-Farm Energy Work
By Nick Ohde

We’ve recently released two new research reports and updated the Energy area on the Practical Farmers website! Check it out here: https://www.practicalfarmers.org/member-priorities/energy/

Some of the new content to check out:

  • Tony Thompson and Jordan Scheibel share their experiences with building walk-in coolers.
  • Two case studies document energy efficiency and weatherization projects at Wabi Sabi Farm and Hawkeye Buffalo Ranch
  • Two new research reports are available: “Farm Metered Energy Analysis” and “CoolBot vs. Commercial Chilling Systems in Walk-in Coolers”

Farm Metered Energy Analysis

For the Farm Metered Energy Analysis, the study attempted to establish a baseline of farm energy use for future research and focus areas. With this information, farmers can identify “energy hogs” and pinpoint the times of year that energy is being used.

One of the big take-aways from this study: very detailed recordkeeping is necessary for tracking energy and identifying problem areas. Farm energy use varies a lot, especially between fruit and vegetable farmers and crop and livestock farmers. Renewable electricity energy options such as wind and solar are available and becoming more affordable, but knowing how much energy you use and when you use it is essential for knowing whether you can make it work on your farm. “If you don’t know how much energy you use, you really can’t determine the feasibility of a project,” says Tim Landgraf of Kanawha.

CoolBot vs. Commercial Chilling Systems in Walk-in Coolers

Walk-in coolers have been identified as a major user of energy on many horticulture farms. In recent years, farmers building their own walk-in coolers have installed window air conditioning units equipped with “CoolBots” as an alternative to a commercial chilling system. The devices override the temperature settings on window air conditioners, allowing them to reach a lower temperature set point.

PFI energy consultant Rich Schuler worked with several farmers to conduct this study comparing the performance and energy use of coolers with walk-in coolers with CoolBots to those with commercial chilling systems. A few of his recommendations:

  • The walls and ceiling of a walk-in cooler should be air-tight, and should have a minimum R-value of 20.
  • Fiberglass insulation with a vapor barrier is not recommended for the primary internal material. Instead of fiberglass insulation with a vapor barrier, closed cell foam is recommended in order to avoid condensation and reduction of fiberglass R-value.
  • In this study, the AC/CoolBot system struggled to maintain temps below 40°F in the heat of the summer.

If you have any energy-related thoughts or ideas, please send them my way at nick@practicalfarmers.org