This document discusses natural and mechanical cooling methods for farm and homestead storage. It begins by describing traditional natural cooling techniques like underground storage, spring water, and ice houses. It then outlines different mechanical cooling systems like venting, fans, refrigeration, and controllers. The document provides examples of different cooling solutions for various storage needs like root cellars, walk-in coolers, and markets. It also discusses important post-harvest care and techniques to remove field heat from produce before storage. Overall, the document provides an overview of both natural and mechanical cooling options and considerations for choosing the right system based on storage needs and scale.
1. Natural and Mechanical Cooling Methods
for Farm and Homestead Storage
Chris Chaisson Kirk Jones
2. Cooling Systems – Natural to Mechanical
• Ground temperature
• Spring water
• Ice
• Outside Air
• Passive venting air exchange
• Active venting air exchange
• Commercial refrigeration
• Controllers
• Freeaire controller – active air/commercial refrigeration
• Coolbot controller – controlled window AC
• Callahan’s Farm Hack system
• myDTC – DIY active air
• myWebController – DIY active system
• Co gen/tri-gen – using heat to cool
• Future Systems/Future needs
4. Which one is better? For whom?
• Wine- Cellar- mechanically controlled
• Cheese- Cellar- mechanically controlled
• Homestead – Small root cellar/Ice
• Farmstead – large root cellar/Ice
• Farm/CSA/Institution- Root Cellar/Walkin
• Small markets- Free aire/Compressor/Cellar
5. Important Post-Harvest Care
• Produce should be harvested
when cold
• Harvest as late in season
• Naturally seasoned
vegetables store longer and
better
• Brix content will be higher
• Remove field heat
– Hydro cooling
– Use mechanical systems
13. Ice Options now
•Cutting and hauling
• Forming in place
•Storage Designs
• Below or above ground
• Sawdust or wood shavings
• Vents and drains
• Gravel/permeable floor
• Thermal mass stone/concrete walls
23. Passive venting a root cellar
•4-6” PVC S+D
•Warm air escape at
ceiling
•Cold air entry 6” above
floor
•Vent through existing
window w/ insulation
and plywood
•Hardware cloth and
screen against insects
and rodents
•Close in Winter
31. Mechanical cooling – refrigeration
• Compressor
• Absorption refrigeration
• Biogas, wood cogen (furnace, kiln), solar –
solar during day and propane at night
• Modify and mix
• Coolbot - Cheaper situation that uses an air
conditioner
• Freeaire
36. FreeAire Benefits
• Cooler Controller Capabilities – Year Round Savings
– Controls Compressor run time: Reduces energy consumption & wear and tear.
– Controls Evaporator Fan run time: Reduces energy consumption, reduces heat introduced
into cooled spaces & wear and tear.
– Defrost Cycle Management (both air and electric defrost cycle): Reduces energy
consumption, reduces heat introduced into cooled spaces.
– Data Logger: Keeps a downloadable record of system component runtime and energy
consumption & savings.
• Cooler Controller Capabilities – Year Round Savings with Optional Features
– Monitors & Manages Door Heater Operation: Reduces energy consumption, reduces heat
introduced into cooled spaces.
– Humidity Monitoring: Monitors and controls humidity levels in cooled spaces and ensures
that humidity levels stay within a user selected range.
– CO2 Monitoring: Monitors CO2 levels and can cycle fresh outside air into a cooled space (with
Polar Power package).
• Cooler Controller Capabilities – Maximum Savings with Polar Power (In Winter)
– Uses outside air for cooling when conditions allow (in conjunction with Polar Power
package): Turns off conventional mechanical refrigeration system components, reduces heat
introduced into cooled spaces, system wear and tear & dramatically reduces energy
consumption.
39. Drumlin Farm Service Barn
(MassAudubon)
Root cellar below, seed and squash
storage above
Renovating main floor into
classroom addition
Insulating South wall,
with newer windows
55. Absorption chillers
• Very Compact
• Few mechanical parts
• Low maintenance
• Runs on waste heat
• Reduces overall fuel use and electricity
consumption
57. Promising Technology
“Small-scale trigeneration system offers hope for
refrigeration in developing world” Refrigeration and Air
Conditioning Magazine, 2014
“All-in-one energy system offers greener power for
off-grid homes, farms and businesses” Engineering and
Physical Sciences Research Council, 2014