On-Farm Cold Storage Facilities

Scott Sanford Sr. Outreach Specialist Rural Energy Program Biological Systems Engineering UW-Madison

1 Crop Storage Parameters l Type of Storage l Crop Volumes l Bulk Storage l Containers l Length of Storage l Short – up to 60 days l Long – 3-12 months l Crop Compatibility l Temperature l Humidity l Ethylene l Odor l Investment

2 Root Cellars l Energy Efficient l Use ground temperature l Outside air for cooling l Temperature subject to ambient temp l Vent warm air / respiration gases ?? l Little/no electrical energy use (fans) l Not suitable for removing harvest heat l Slow transfer of heat l Access for material handling?? l Can’t afford to hand carry crops in and out 3

Source: http://www.kk.org/streetuse/redneck_root_cellar.jpg Modern Root Cellar Concept l Earth Contact basement l Average ground temperature – 49F l Office/living 2nd Floor l Why not under-ground? l Fork Truck Accessible l $36,000 (2001)

Carrots Winter Squash pallets Bins on racks 35-38°F 50°F Staging Area Potatoes Bulk Bins 42-45°F 4 Modern Root Cellar Concept l Outside air cooling l Outside air used when l Cooling is needed & l Outside air colder than inside temperature l Computer controlled l Fans and Dampers l Mixing Fans & heaters

5 More information at http://smfarm.cfans.umn.edu/rootcellar.htm Refrigerators l Self contained l Great for smaller quantities l No humidity control l No planned air exchange l Space efficiency? l Do containers fit shelving? l Solid doors more energy efficient than glass l Limited capacity to remove field heat l Cost effective for small grower / short term storage

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Source: http://www.selectappliance.com/exec/ce-product/tl_g20000 Walk-in / Drive-in Coolers l Workhorse of industry l Rule of thumb l 2.5 to 3 cu. ft. of cooler volume per bushel l 1.24 cu ft / bushel – 50% utilization l Modular or built-in-place l Features: l Lockable door l Well insulated walls l Washable interior l Temperature control l Floor drain l Insulated floor l Self closing door

7 Source: http://www.webstaurantstore.com/nor-lake-walk-in-cooler-6-x-12-x-6-7-indoor/596KLB612.html Walk-in / Drive-in Coolers l Manufactured panels l Modular tongue/groove panels l Walls and Roof l 2” to 12” thick l Insulation l Closed Cell Foam l 4” minimum (R-25) – 6” better (R-38) l Urethane or Polystyrene l Vapor barriers l Installation l Easy to assemble l Locking cams l Ceiling or floor to wall l Cam locks or bolts 8 l Caulk all seams Source: http://www.kingspanpanels.us/ColdStorage/ThermalspanWall/200-Inverted-Rib.aspx http://www.master-bilt.com/pdfs/io_manuals/walk-in_io.pdf Built-in-place Cooler l Insulated walls – l R-25 minimum (EPACT 2005) (R-30+ recommend) l Fiberglass insulation NOT recommended l Wet insulation reduces insulation value l Foam - Polyurethane / Polystyrene l R-value - 4 to 6.5 per inch l Vapor barrier – warm side (not needed with Foam) l Year round storage – warm side changes l Insulated floor l 1-2” foam board under concrete – 25 or 40 PSI rating foam l Washable interior surface l Fiberglass / plastic / steel l Drain – condensation / clean-up l Cost - ~ same as used cooler panels (labor & floor excluded) l 12 x 12 x 8 – $5500 w/ refrigeration 9

Insulation Materials l Foam – (4” minimum – 6” better)) l Types l Urethane (yellow) l Expanded Polystyrene (pink/blue) l Insulation value – R-4 to R-6.5 l Foam in place – seals all edges Foam R-Value l Rigid Board Thickness l Tongue & groove – tape all seams 3 19 l Double layer with offset seams 4 25 l Cover to protect 5 31 l Steel / plastic corrugated sheeting 6 38 l Fiberglass board 8 50 l Flammable – protect from heat sources 10 63 l No vapor barrier needed 10 12 75 Self-contained units l Truck/Trailer Reefer l Higher Heat losses/gain l 2.25” to 3” foam l Smaller refrigeration system l Designed to maintain the temperature of product l Air flow may not be ideal l Access for Material Handling

11 Source: http://www.portablecoldstorage.com/ Refrigeration System – Direct Expansion

In-Cooler

Pre-heat water 12 Source: Refrigeration and Controlled Atmosphere Storage for Horticultural Crops – NRAES-22 Types of Refrigerants l New systems – R404a l Used Systems l Avoid l R-12 - restricted sales (ban as of Jan 1, 2015) l R22 - Jan 1, 2010 ban the use in new equipment § Production creases Jan 2020 § Can use a replacement refrigerant for existing equipment l Acceptable Refrigerants l R134a – restricted sales (March 2004) l R404a l It is illegal to intentionally release any refrigerant 13 Evaporator Fan motors

l Can be higher cost to operate than compressors l Run to promote air mixing l Evaporator Fan Controller § Reduces fan speed when compressor not running l PSC – Permanent Split Capacitor (old) l Full load efficiency – 50-60% l Lower efficiency at lower speeds l EC – Electronically Commutated (new) l Efficiency - 65 – 80% l Typically 30-50% energy savings

14 Refrigeration Sizing l Field heat removal l Heat of respiration l Conduction heat gain / loss l Convection heat gain / loss l Infiltration l Air exchange (opening of door) l Equipment heat gain l Lights, fans, fork truck

15 Refrigeration Requirement

l Field heat Removal l Largest component l Short duration l Smaller for Fall harvested crops l ΔT x lbs x SH l Slow removal effects produce 16 Source: Refrigeration and Controlled Atmosphere Storage for Horticultural Crops – NRAES-22 Precooling l Hydro-cooling – Water bath l Forced air cooling l Ice Pack l Vacuum Cooling

17 Heat of respiration table

18 Source: Refrigeration and Controlled Atmosphere Storage for Horticultural Crops – NRAES-22 Refrigeration Sizing l Total refrigeration requirement l Use maximum (worth case) values for each

Qt = QFH+ Qresp+ Qcond+ Qinfil+ QEquip l Capacity of refrigeration system

Capacity = Qt x SF x DF

l SF = service factor, typically 1.1 to 1.2 l DF = defrost factor, typically 1.1 to 1.2 l One ton of Refrigeration = cooling based on melting 2000 lbs of ice in 24 hrs l 288,000 Btu/24 hrs or 12,000 Btu/hr 19 Compressor Capacity Recommendation for Small Coolers

20 Source: Refrigeration and Controlled Atmosphere Storage for Horticultural Crops – NRAES-22 Small Refrigeration Systems l CoolBot Controller l Over-rides standard window air conditioner controls l Cooling capacity less than rating at lower temps l Maybe lower capacity than require for field heat removal l Multiply units may be needed l Self-Contained Refrigeration unit l Condenser, compressor & evaporator – one unit l Plug and Play – no Refrigeration tech needed l Higher / known capacity l Circulating fan l Roof top or side-mount l Inside or outside l Warranty 21 Temperature Ranges for crops l Cold & Wet l Beets, cabbage, carrots, turnips, parsnips l 32F & RH 95%+ l Cold & Dry l Onions / Garlic - 32F & RH 65-70% l Cool & Wet l Potatoes - 40-50F & RH 95% l Warm & Dry l Winter Squash - 50-55F & RH 50-70% l Sweet Potatoes - 55-60F & RH 80-85% 22 Storage Guidelines for Fruits & Vegetables, E. de Long, S. Reiners, Cornell Cooperative Extension-Chemung Co., 2004 http://www.gardening.cornell.edu/ factsheets/vegetables/storage.pdf

23 24 Humidity control l Add moisture to air to reduce crop moisture loss Gellert Company l Evaporative cooler pad l Atomizer l Misting l No water on crops l Pack in Plastic bag l Pack crops in damp sand or sawdust Source: http://ivi-air.com/ 25 Humidistat l Accuracy range l Range to 99% l Accuracy - 3-4% or less l Resolution – 1% or less l Smallest display digit l Accuracy decreases >90% l Remote sensor desirable l Locate in air flow l Enclosure designed for wet environment l Cost $130 - $500

26 Humidity Control l Refrigeration dehumidifies air l Low temp drop à large evaporator surface area

27 Source: Refrigeration and Controlled Atmosphere Storage for Horticultural Crops – NRAES-22 Outdoor air to reduce refrigeration l Exchange air l Controls l Manual l Automatic l Temperature l Time of day l Disadvantage l Loss of humidity l Colder air is dryer

28 Air Flow/Ventilation Patterns

29 Cold storage – clearances & air flow pattern 12-18” clearance

8-10” space

8-10” space

l Nothing stacked above bottom of evaporator l Wall clearance allows air to cool product 4-6” space l Space under and between containers

30 Air Flow with Plenum Wall • Horizontal slots in plenum wall • Use for Force-Air pre-cooling • Bins stacked tight • Humidification in plenum • 2-way fork slot – air duct Fan

Refrigeration Humidification

Plenum

Block end 31 of fork slot Bins & Tots l Materials: l Wood – heavier, absorb moisture, repairable l Plastic – FDA approved, easily sanitized, repairable? l Rated for loading l Stackable (without lid) l Vented / solid sides / bottom l Minimum 8-11% of bottom open l Handle with Fork Truck or Pallet Jack l Fit standard racking l Hand holes

32 Racking l Allows better access to individual containers l Better ventilation and cooling l Keep containers off floor l Wire shelving – better air flow l Rolling racks for small walk-ins

Source: http://ervojic.hr/images/uploads/paletni-regali-velika.jpg 33 http://www.ancostorage.co.uk/acatalog/Kwick_Rack.html http://www.martforcarts.com/carts/3.html Material Handling Equipment l Pallet Jacks l Pallet Lift l Need smooth level hard surface l Narrower aisle than needed for fork truck l Fork Truck l Skid Steer w/ Pallet Forks

Source: http://www.beechhandlingservices.co.uk/ 34 http://www.prestolifts.com/stuff/contentmgr/files/ Source: http://www.getprice.com.au/images/uploadimg/910/350__1_pallet_jack.jpg f243d69b64cf66fa30c5f6092fccb8ec/misc/pallet_stacker.jpg Layout Issues – Door Location

• Door location doesn’t allow maximum number of containers

35 Layout Issues – Door Location

• Allows last container to go straight in.

36 Layout for accessibility

• Add doors to reduce aisle space inside cooler • Small goods and Bulk area

Bulk Produce in Pallet Bins Racking Racking

Aisle

Third Door for First in – First Out 37 Layout for accessibility • Small quantities / fragile goods / packed produces

Racking

Small quantities / Bulk Produce in Packed produce Pallet Bins

Racking

Aisle

Racking

38 Planning!!! Packing l Space requirements l Material Flow Cleaning l Access to processing area l Material Handling l Utility needs l Water Produce from Employee Fields space l Electricity l Drains l Temperature Storage l Labor Office l Future Expansion 39 Flow Charts – by crop

From Field Wash Bulk Bins Long-Term Storage Oct - Feb

Truck to Packing Sort by 34°F Market 5# mesh size @ 95% RH bags A & B

Short- term Culls – Storage Food Bank Food-bank / Compost Compost Pile 40 Building Layout

Ramp to Fields Loading Dock

Lunch Rm / Belt washer Cooler #1 Employee Lockers Hydro-Cooler

Bath / Work Alleys Cooler Shower Access Cooler #2 Room Sorting equipment Alley

Packing Line Office Cooler #3 Supply Storage Racks

41 Economics of Storage Crops Factors to consider: lCost to build and operate storage units lFacilities and capacity to move, wash and pack heavy, bulky items during the winter lShrink (spoilage and grading) – 5 to 40% lLabor costs (benefits) lMarkets and Pricing l 20% higher costs l Handling/storage lRisk and rewards l Cash flow during normally low period

42 Storage Facility Capital Cost l Multiple units may be needed if you plan to store different products l 12 x 12 cooler: $8,000-$9000 (new) $4,000-$6,000 (used) l 20 x 30 cooler: $20,000-$24,000 (new) $12,000-$14,000 (used) l Electric costs to run cooler: l $2 to $4 per day. l Supplemental heating required

l Storage units in unheated building/outside 43 Storage Crop Case Studies Farm A Farm B Farm C Farm D Cubic Feet of Storage Space 812 6,000 17,374 22,400 Crops Roots, Alliums, Roots, Alliums, Roots, Cabbage, Squash, Squash, Cabbage, Carrots, Cabbage, Cabbage Alliums, Butternut Sweet Potatoes Squash, Sweet Potatoes Owner Owner + 1 part- Owner + 5.5 Owner + 8 Winter Labor (2-4 hrs / wk) time (30 hrs / (80-90 hrs / wk) (280 hrs / wk) wk CSA Direct Direct Direct (Direct Wholesale Wholesale Wholesale Markets Wholesale) CSA and (f. mkts) Distributor & (CSA) (CSA)

Gross Sales $14,400 $85,000 $136,000 $250,000

44 Gross / cubic $18 $14 $8 $11 ft Person hours per $1000 in 2.4 7 11 24 sales Farm Storage Facility Loan Program l Low interest financing l Fixed rate for 2.000% - 7yr, 2.625% - 10yr , 2.875% - 12 yr l Up to $500,000 l 15% down l Build or upgrade storage and handling facility l New cold storage (Used equipment not eligible) l Framed structure or prefabricated permanently installed l Permanently affix equipment – refrigeration system, lighting, controls l Useful life of 15 years or more l Administered by Farm Service Agency l http://www.fsa.usda.gov/FSA/webapp?area=home&subject=prsu&topic=flp-fp

45 Summary l Know the storage requirements for each crop l Market within the expected storage duration l Plan storage facilities into work flow / traffic l Use Foam insulation!!! l Plan for expansion l Sanitize storage and containers between seasons l Price produce to cover additional costs

46 Resources l Bartsch, J.A.,G.D.Blanpied,”Refrigeration and Controlled Atmosphere Storage for Horticultural Crops”, NRAES-22, Natural Resource, Agriculture and Engineering Service, Cornell U., Ithaca, NY, 1990. (Out of Print) l Roper, T., K. Delahaut, B.Ingham., Storing fruits and vegetables from the home garden, A3823, University of Wisconsin-Extension, 2006. http://learningstore.uwex.edu/Assets/pdfs/A3823.pdf l _____, The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Stocks, USDA-ARS, Agricultural Handbook Number 66, 2004. Available at http://www.ba.ars.usda.gov/hb66/contents.html l De Long, Eric, Storage Guidelines for Fruits & Vegetables, Cornell Cooperative Extension, 2004. http://www.gardening.cornell.edu/factsheets/vegetables/storage.pdf l Fruit & Vegetable Post Harvest & Storage Information – Website with data sheets on crops from Ambarella to Zinnia. http://www.postharvest.com.au/Produce_Information.htm l Wilhoit, J., Low Cost Cold Storage Room for Market Growers, AEN-96, University of Kentucky Extension, 2009 http://www2.ca.uky.edu/agc/pubs/aen/aen96/aen96.pdf l Bubel, Mike & Nancy, Root Cellaring, 2nd Ed, Storey, Pownal, VT, 1991

47 Questions??

Scott Sanford Senior Outreach Specialist Biological System Engineering University of Wisconsin [email protected] 608-262-5062

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