General grain dryer report.pdf - The Minnesota Project

Jennifer Brinker C.E.M. 

Office: 608-‐354-‐0185 

440 Science Drive Suite 400 Cell: 608-‐354-‐8534 

Madison, WI 53711 

jennifer.brinker@gdsassociates.com 

March 30, 2012 

¢¢¢¢¢¢¢¢ 

¢¢¢¢¢¢¢¢ 

¢¢¢¢¢, MN ¢¢¢¢¢ 

Dear ¢¢¢¢¢¢¢, 

GDS is pleased to present the results of your grain drying facility energy assessment. This 

documentation provides baseline energy use data for your facility as well as the expected energy 

consumption with your planned grain transport retrofit and added grain dryer. All savings calculations 

are based solely on the equipment which is effected by the efficiency upgrade. 

Summary Table 

Baseline grain dryer efficiency –weather normalized (btu/lb) 

1,778 

Proposed grain dryer efficiency (btu/lb) 

1,722 

Baseline grain handling electric consumption (kWh) 

1,288 

Proposed grain handling electric consumption (kWh) 

2,296 

Percent Savings -%* 

1.4% 

Annual Savings - $* 

-‐$116 

*There are savings on a Btu-‐basis, but an increase in the ratio of electrical-‐to-‐LP gas energy. Electrical energy is more expensive 

than LP gas energy on a $/Btu basis. 

Based on these results, we recommend that you continue to use the existing grain drying to capacity 

and select another dryer to handle the expected overflow. The information regarding the existing and 

proposed system are summarized in this report. The baseline efficiency value was determined by 

examining three years of historical utility data, bushel throughput, and moisture in and out values. 

Baseline values were weather normalized by comparing historical temperature data to each season’s 

respective weather conditions. The proposed efficiency value was determined from field research 

conducted on similar grain systems along with expected dryer operation efficiency for the respective 

climate and area grain moisture conditions. 

If you have any questions regarding your energy audit please give Jenny Brinker a call. We appreciate 

the opportunity to learn and work with your facility. 

Sincerely, 

Jennifer Brinker C.E.M. 

Energy Advisor 

608-‐354-‐8534 

Mark Bergum P.E. 


Joe Schultz, C.C.A. 


1

Preface and Acknowledgements 

Despite the importance of greenhouses to Minnesota’s economy, little 

has been done to bring operations up to speed from an efficiency 

standpoint. The Minnesota Project recognized the increased demand 

for green house auditors through its previous work on greenhouse 

efficiency and the need for energy audits for federal rural funding 

programs like the USDA’s Rural Development and Natural Resources 

Conservation Service. 

This energy audit was conducted as part of an energy auditor training series. Twenty trainees who work 

in agriculture or energy fields collaborated to collect and analyze energy information related to grain-drying 

operations. The final report was compiled and reviewed by a GDS Associates, Inc., an energy 

auditor firm and certified USDA Technical Service Provider. 

This project was made possible by a grant from the U.S. Department 

of Energy and the Minnesota Department of Commerce (Division of 

Energy Resources) through the American Recovery and 

Reinvestment Act of 2009 (ARRA). 

2

3 

4 

1 

IBD 

2 

1 – 10,000 Bu Corn Storage Bin 

2 -‐ 45,000 Bu. Corn Storage Bin 


4 –65,000 Bu Corn Storage Bin 

BB – 4,400 Bu Bean Bin 

WB – 9,200 Bu Wet Bin N 

IBD – In Bin Dryer 

S 

B 

W 

B 

Situation Report: 

The farm and grain drying facility is in southwest Minnesota. Over the past 3 years the farm has 

averaged a throughput of 195,000 bushels of corn per year. In the 2011 drying season this value totaled 

192,000 bushels of corn. Business plans include expanding the volume of grain dried and to add both a 

new mixed flow-‐type dryer and pneumatic (forced air) grain transport system. With the proposed new 

grain drying set-‐up, The farm is expecting to dry 250,000 bushels of corn per year. An average field 

moisture content of 23.0% is used in the proposed grain facility calculations as this is the state average. 

The farm plans to dry grain down to 14.0% for long term storage, thus this will be used as the final point 

value. 

An average propane energy cost of $1.47/gallon was noticed over the past 3 drying seasons while a 

current electrical energy cost of $0.115/kWh was noticed (based on the past 12 months). For this report, 

the average gallon cost will be used for the proposed system while the current electrical cost will be 

used. This methodology is chosen because thermal energy costs fluctuate both up and down, while 

electrical costs are generally stable or increase gradually with time. Historical energy data can be seen in 

the attached documents. 

3

Current Dryer System: 

The current dryer system being utilized is a Shivvers dryer 

and auger system within a 27-‐foot grain bin. This unit is a 

continuous in-‐bin dryer. The current dryer has a 

throughput capacity of 1000 bushel per hour with a 3-‐point 

decrease. This unit is undersized for the needs of the 

facility’s future grain production. The efficiency of the 

current dryer is estimated to be 1,778 Btu/lb of water 

removed. This efficiency value was determined from the 

farm’s historical energy usage and bushel throughput data 

obtained from the producer. It should be noted that the 

farm is operating at an optimal drying efficiency, using a 

recommended energy-‐efficient grain dryer. It is not 

uncommon to audit dryers in operation that use more than 

2200 btu/lb of water removed. The current grain handling 

system is an auger system with four motors that total 8.8 

kW of power load. 

Figure 1. Existing Shivvers Dryer Interior 

Proposed Dryer System: 

The farm is proposing the installation of a mixed flow type 

of grain dryer and to retrofit their current auger system with 

an 18.8 kW pneumatic (air) grain handling system. The 

additional dryer and pneumatic grain handling system will Figure 2. Current Shivvers in-‐bin dryer with fan. 

accommodate plans for adding about 50,000 bushels to the 

current 200,000 bushels per season grain throughput. The farm plans to run both the current Shivvers 

dryer plus the mixed flow dryer. Mixed flow dryers are upright columns where grain flows down, 

passing through multiple heating zones. Mixed flow dryers are recommended as an energy efficient 

grain dryer choice, and use 25% to 40% less energy than a standard cross-‐flow dryer (considering a 

cross-‐flow without heat recovery options) while maintaining high grain flows and volumes of drying. The 

efficiency of the proposed dryer used in combination with the existing Shivvers dryer is estimated to be 

1,722 Btu/lb of water removed. This data was obtained from research data conducted in the field on 

similar models grain systems. 

The farm plans to retrofit the existing bin-‐to-‐bin auger transport system with a pneumatic (air) grain 

transport system. The current auger system includes four 3-‐horsepower (12 hp) direct-‐drive (one 

speed) motors and the proposed system will replace these motors with one, 30-‐horsepower soft start 

and stop motor. Components of pneumatic grain systems typically include the blower fan and motor, 

air lock which drops grain into airstream, and velocity compensators that control grain speed at elbows, 

prevents damage. It should be noted that although the pneumatic grain system will be more convenient 

and allow less run-‐time, the electricity consumption may increase versus the existing auger system. 

Historical Utility Data: 

Data provided below was obtained from farm utility bill information provided by McLeod Cooperative 

Power Association and from the farm’s owners (LP is purchased from Hutchinson Coop). The usage seen 

below only includes energy used during the drying season. An average LP gas energy cost of 

$1.47/gallon was noticed over the past 3 drying seasons while a current electrical energy cost of 

$0.115/kWh was noticed. 

4

average 

year 

bushels of 

corn dried 

LP gas cost for 

season 

LP gas used 

(MMBtu) 

electricity cost 

for season 

electricity 

used 

(MMBtu) 

annual 

efficiency 

(btu/lb) 

2011 192,000 $3,658 183.0 $2,907 76.9 1,381 

2010 192,000 $6,296 411.8 $1,914 56.3 1,477 

2009 201,000 $24,549 1,921.5 $4,995 166 2,414 

Table 1. Historical grain throughput and energy used to dry grain. 

Grain Drying Energy and Cost Savings: 

Savings are based upon utility data obtained from the farm between 2009 and 2011 drying seasons. 

Savings do not account for fuel price fluctuations or changes in crop harvest moisture levels. Cost 

savings were based upon energy cost averages shown above. A grain throughput value of 250,000 was 

chosen based upon projected future farm totals. The overall savings with the new grain dryer is 1783 

MMBtu. This value equals an efficiency gain of 1.4% with a cost increase totaling $116 annually. 

average 

bushels 

per year 

LP gas used 

per year 

(MMBtu) 

electricity 

used per year 

(MMBtu) 

Energy 

totals 

[MMBtu] 

drying cost per 

bushel 

[23% to 14%] 

annual 

energy cost 

Current dryer 

1,973 74 2,047 $0.14 $34,093 

Proposed dryer 250,000 1,912 106 2,018 $0.14 $34,209 

Savings: 61 -‐33 29 $0.00 -‐$116 

Table 2. Summary of current and proposed grain operation energy consumption per season. 

As stated in the introductory letter, the additional dryer and pneumatic handling system offer savings on 

a Btu-‐basis, but an increase in the ratio of electrical-‐to-‐LP gas energy. Electrical energy is more 

expensive than LP gas energy on a $/Btu basis. 

Greenhouse Gas Reduction: 

Emission total and greenhouse gas reduction savings for electrical energy are only associated with 

emissions from the power plant. LP gas emission savings are attributed to the reduction in combusted 

fuel needed to dry a bushel of grain. Greenhouse gas emissions reductions metrics are provided by GDS 

Associates, Inc. using Climate Registry protocols set forth by the U.S. EPA in Table 3. 

Metric tons carbon 

dioxide equivalent from 

LP gas (mt CO 2 e) 

Metric tons carbon 

dioxide equivalent from 

electric energy 

(mt CO 2 e) 

Total metric tons carbon 

dioxide equivalent 

(mt CO 2 e) 

Current dryer 125 18 144 

Proposed dryer 121 26 148 

Savings [ mt CO 2 e] 4 -‐8 -‐4 

Table 3. Greenhouse gas statistics for the proposed system. 

5

3 

4 

1 

IBD 

2 


2 -‐ 45,000 Bu. Corn Storage Bin 


4 –65,000 Bu Corn Storage Bin 

BB – 4,400 Bu Bean Bin 

WB – 9,200 Bu Wet Bin N 

IBD – In Bin Dryer 

S 

B 

W 

B 

Figure 3. Grain facility aerial photo and dryer and system layout. 

Grain Facility Footprint: 

Figure 4. Top of Shivvers dryer and 

unload auger to Bin 2. 

The current drying system is augured to 5 holding bins on site. The 

bins and their holding capacities are listed below. These structures 

encompass the impacted storage units affected by the new grain 

drying system. 

Bin Name 

Holding Size (bushels) 

1 10,000 

2 45,000 

3 65,000 

4 65,000 

“Bean Bin” 

4,400 

Wet Bin 

9,200 

Table 4. Grain storage bin labels and sizing. 

6

Motor Replacement Inventory: 

The following is a listing of motors that are currently located on site at the grain facility which will be 

affected by the new pneumatic grain transport system. The owners hope to retrofit the current bin-‐to-bin 

transport system with a 30 horsepower, pneumatic (air) grain handling system. A few motors 

changes will be conducted in order to complete the retrofit. The affected motors are inventoried below 

in table 5. 

Application 

(description) 

current 

motor 

size 

(hp) 

current 

motor 

efficiency (%) 

current 

motor 

size load 

factor 

current 

motor 

run 

hours 

per year 

Bin 2 Auger 3 85.0% 0.85 144 

Bin 4 Auger 3 85.0% 0.85 144 

Bin 3 Auger 3 85.0% 0.85 144 

Other Bin Auger 3 85.0% 0.85 144 

Table 5. Motor schedule for the current and proposed grain transfer systems. 

proposed 

motor 

size (hp) 

proposed 

motor 

efficiency 

(%) 

proposed 

motor 

run 

hours 

per year 

proposed 

motor 

load 

factor 

30 95.0% 122 0.8 

Application 

(description) current kW 

current 

kWh 

Bin 2 Auger 2.2 322 

Bin 4 Auger 2.2 322 

Bin 3 Auger 2.2 322 

Other Bin 

Auger 2.2 322 

Total: 1,288 

proposed 

kWh 

2,296 

proposed 

kW 

18.8 

Table 6. Motor energy use for the current and proposed grain transfer systems. 

kWh 

Savings 

-‐1,008 

The farmer is interested in a pneumatic handling system because it will allow for more flexibility in 

unloading. Plus, it was stated that he would be able to reduce energy consumption and load as a result 

of the pneumatic grain relay system. He projects the pneumatic system will come with a soft-‐start 

motor and may allow for 15% less run time as the grain will be transported faster than the current 

system. However, while time of use may decrease, there will be an anticipate increase in motor load on 

the farm as a result of installing this system based on Table 6. Currently the auger relay system results 

in a load range of 6 hp to 9 hp depending on the bins the grain is being transported to. The proposed 

change under the pneumatic system will be 30 hp. This is an 70%-‐80% increase motor loading. Based 

on the stated objectives of the producer to reduce energy and reduce motor load, this project will not 

result in one or the other. It is suggested that the farm closely evaluate the installation of a pneumatic 

system ensure all of the installation objectives are met. 

7

Other Motor Inventory: 

The following is a listing of motors that are currently located on site at the grain facility which will not be 

affected by the new pneumatic grain transport system and addition of a mixed flow dryer. 

Application 

(description) 

current motor size 

(hp) 

motor load 

factor 

current motor 

efficiency (%) 

annual run time 

(hours) 

Bin 1 Fan (pictured) 10 85.00 89.5% 144 

Bin 2 Fan(pictured) 10 85.00 89.5% 144 



Bean Bin 3 85.00 85.0% 144 

Wet Bin 5 85.00 85.0% 288 

Wet Unload 3 85.00 85.0% 288 

Unload Auger 10 85.00 89.0% 288 

Dryer Spreader 0.75 85.00 85.0% 288 

 

Sweep Augers 5 85.00 85.0% 144 

Upright Auger in Dryer 

(pictured) 10 85.00 88.0% 144 

Shivvers Fans 

(pictured) 13.5 x 4 85.00 85.5% 288 

Table 7. Motor schedule for the grain dryer and storage facilities. 

Figure 4. Bin 1 fan motor nameplate. 



Figure 6. Bin 4 fan. 

8

Figure 9. Upright unload auger for Shivvers 

dryer. 

Figure 8. Shivvers fan motor. 

9

Additional Business Incentives Appendix 

The Database of State Incentives for Renewables & Efficiency (DSIRE), found online at dsireusa.org, has 

up-‐to-‐date information on grants and incentive programs available by state. The following incentive and 

grant information was compiled from the DSIRE website on February 10, 2012. It is recommended to 

check with your utility company and local government entities for more details or additional funding 

opportunities. 

McLeod Cooperative Power Association 

McLeod Cooperative Power Association offers its members various rebates, grants and loans intended 

to improve the energy efficiency of your operation. For example, there is a $15 per horsepower 

incentive to upgrade to a premium efficient motor (up to 200 HP). There is also a $30 per horsepower 

incentive to go to a variable frequency drive (VFD) which can be used in addition to the $15 per HP 

premium efficiency motor incentive. 

Contact: 

Shannon Jerabek 

Energy Management Specialist 

McLeod Cooperative Power Assn. 

PH. # (320)864-7327 or Toll Free 1-800-494-6272 

sjerabek@mcleodcoop.com 

Web Site: http://www.greatriverenergy.com/savingelectricity/energyefficiency/ 

USDA-‐Rural Energy for America Program (REAP) 

Note: The U.S. Department of Agriculture's Rural Development issues periodic Notices of Solicitation of 

Applications for the Rural Energy for America Program (REAP). The deadline to apply for loan guarantees 

under the most recent solicitation is June 29, 2012, though combined grant and loan guarantee 

applications and grant only applications have an earlier deadline of March 30, 2012. For more 

information, see the NOFA in the Federal Register. Grants and loan guarantees will be awarded for 

investments in renewable energy systems, energy efficiency improvements and renewable energy 

feasibility studies. 

Maximum Incentive: 25% of project cost 

Contact: 

Minnesota USDA Rural Development Office 

375 Jackson Street 

Suite 410 

St. Paul, MN 55101-‐1853 

Voice: (651) 602-‐7800 

Fax: (651) 602-‐7824 

www.rurdev.usda.gov/mn/ 

10

Natural Resources Conservation Service-‐Environmental Quality Incentives Program 

The Natural Resources Conservation Service (NRCS)-‐Environmental Quality Incentives Program (EQIP) 

offers funding through conservation activity plans related to energy management. EQIP offerings for 

2012 are being finalized, and it may be best to talk to your local NRCS representative to learn more. 

Contact: 

NRCS SERVICE CENTER OFFICE 

GLENCOE SERVICE CENTER 

2570 9TH ST E 

GLENCOE, MN 55336-‐3354 

(320) 864-‐5177 ext 3 

(320) 864-‐5737 Fax 

Clayton Schmidt 

District Conservationist 

(320) 864-‐5177 ext 3 

(320) 864-‐5737 fax 

Clayton.Schmidt@mn.usda.gov 

Mailing Address: 

2570 9TH ST E PO BOX 160 

GLENCOE, MN 55336-‐3354 

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APPENDIX -‐ Figure 10. Historical Electric Data 

12

General grain dryer report.pdf - The Minnesota Project

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