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Natural and Mechanical Cooling Methods for Farm and Homestead Storage Chris Chaisson Kirk Jones
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
Why Natural or Mechanical?
Seasonal Storage (cool seasons)
• Vents
• Fans
• Freeaire Polar Package
Year Round Storage
Ice
Compressor
walk-ins
Coolbot
Mix: Freeaire/conventional
vents and coolbots
Co/Trigeneration
absorption refrigeration
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
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
Field heat
Traditional In-Ground StorageCitrus fruit storage cave in Cappadocia, Turkey
Women culling lemons and repackaging for shipment
Spring House for Cold Storage Denning, Ulster County, New York
Community ice harvests
Ice in Colonial America
Thompson's Ice HouseSouth Bristol, Maine
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
Rainbow Heritage
The cave construction 1
Cave construction 2
Cave construction 3
Cave Construction 4
Ice in Harvest
• Tapered plastic tubs
• -20F is ideal
Ice in theCarrot Cave
Ice thermal values•Thermal Conductivity, 2.2 W/m-K•Heat capacity, 2.1 kJ/kg-K•Heat of Fusion, 333.55 kJ/kg
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
Adamah Adam
Venting details
120 CFMSimple in-line fan
and damper
Active Venting
Dampers and duct fans
Spring loaded 4” backdraft dampers, $20 each
4” In-line duct fan, $29 ea
Adamah Retreat Center
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
FreeAire System
FreeAire components
Web Interface
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.
Chris Callahan (UVM AgExt)Outside Air Hack
Set the Temperature between 35 and 40F
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
Root CellarCold and Moist Chambers
Squash Room and Seed Storage
Drumlin Cellar Venting
Drumlin Cellar Electrical
Drumlin Attic Venting
Drumlin Attic Electrical
myDTC8
Powisset Barn Crop Storage
Powisset Crop Storage – Design Phase I
Powisset Barn – Trustees of Reservations
Powisset – Design Phase II
myWebController.comWebRelay-10
Coolbots
• More efficient above 35F if well insulated and doors stay closed
Cogeneration –Combined Heat and Power
Trigen systems
Absorption chillers
• Very Compact
• Few mechanical parts
• Low maintenance
• Runs on waste heat
• Reduces overall fuel use and electricity consumption
Traditional RV Schematic
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
Thank You!!
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