Ag & Energy - Lesson 3 - Conservation Practices

Author

Will Fett

Published

6/27/2014

Ag & Energy - Lesson 3 - Conservation Practices

Topics:

Lesson Plans - 9th - 12th

Target Grade Level / Age Range:

Grades 9-12

Time:

50 minutes

Purpose:

By the end of this lesson, students will be able to:

Understand how changes in tillage practices have increased energy conservation and efficiency.
Identify practices where energy conservation and efficiency could be realized in drying grain.
Identify practices in raising livestock where energy conservation and efficiency could be realized.

Materials:

Projector
Writing surface
Computers or tablets with internet connection
3x5in note cards

Suggested Companion Resources

Energy Estimator for Tilling http://ecat.sc.egov.usda.gov/
Energy Estimator for Irrigation http://ipat.sc.egov.usda.gov/
Energy Estimator for Nitrogen http://nfat.sc.egov.usda.gov/
Energy Estimator for Animal Housing http://ahat.sc.egov.usda.gov/

Vocabulary

Energy Conservation: reducing or eliminating usage to save energy
Energy Efficiency: getting the most productivity from every unit of energy
Ballasting: give stability to by adding a heavy weight
Tire inflation: Ensuring recommended air pressure in each tire

Interest Approach or Motivator

Review the student’s farm designs from the previous class (Lesson 2). Did any of the grain farms include a grain dryer? What kinds of energy efficiency and energy conservation did they include in livestock facilities?

Today’s lesson will look more closely at how changes in management practices can help conserve energy and increase efficiency.

Procedures

Objective 1: Understand how changes in tillage practices have increased energy conservation and efficiency.

Present the information in slides 2-4 as background information for the students. Have students capture the information into their notes.

Since research began in the 1950s, studies have shown that leaving stubble from the last harvest (no till) offered protection from drought and erosion. Today, fuel costs are a major incentive to practice no-till or minimum-till farming.

Equipment sizing: Match your machinery to the power requirements of the job. Don’t use a big tractor to pull smaller loads, and try to plan for multi-function operations.

Fuel Savings through physics: Proper ballasting is important to transfer as much engine power as possible to the drawbar. Too little weight results in excessive slippage and waste of fuel. Too much weight lowers wheel slip but results in greater rolling resistance and fuel consumption.

Proper tire inflation also affects fuel consumption. Correct tire inflation pressure for the load carried can be found from load and inflation tables.

Direct students to computers or tablets with internet access. Have them navigate to: Energy Estimator for tillage http://ecat.sc.egov.usda.gov/. Walk through the first example together as a class. Enter 300 acres of corn and 200 acres of soybeans. Enter $2.30 as the price of diesel fuel per gallon.

Pass out the student worksheet. Have students use the estimator to answer the accompanying worksheet. Give students 5 to 10 minutes to complete the worksheet. Have them check their answers with a partner and review answers as a class before moving on to objective #2.

Objective 2: Identify practices where energy conservation and efficiency could be realized in drying grain.

Drying grain can constitute a substantial use of energy. Have students capture the following information into their notes. Drying grain is important to prevent spoilage during storage. Grain is sold by weight and moisture content is measured at the time of sale. Too much moisture or too little moisture will result in a lesser price.

Grain Dryer (propane)
1. Keep grain free of dirt and chaff.
2. Inspect drying floor regularly to assure free airflow
3. Avoid over-drying by checking moisture content frequently
Motor grain augers (electrical)
1. Fit your motor size to the size of your job.
2. Inspect motors regularly. Clean them as needed.
3. Get energy-efficient motors when purchasing new motors.
  Provide the following information. Have students work in groups of two or three to compare and contrast the three different types of grain dryers: low temperature bin dryers, conventional flow-in bin dryers, and dryeration. Students can use worksheet #2 to record their work.
Compare and contrast
1. Low temperature bin dryers:
  1. Low temperature bin dryers use high capacity fans to push slightly heated air through the grain to promote drying. The air is heated with electrical resistance heaters up to 10 degrees Fahrenheit (6° Celsius) above ambient temperature. The slight heating of the air reduces the relative humidity of the air and results in faster drying compared to ambient air or natural air bin dryers. Some growers only use the heaters during periods of high humidity so drying is not delayed or slowed. The amount of airflow, measured in cubic feet per minute (cfm) per bushel, varies according to regional differences.
  2. A low temperature bin dryer contains a full perforated floor, fans with capacity of 1 to 1.5 cfm per bushel or higher, grain spreader and grain unloading equipment.
  3. The moisture content of the grain that can be dried in this type of dryer is limited to a maximum of about 24% without spoiling but is subject to the harvest date and yearly weather. Early harvest (September 1) would have a maximum grain moisture content of 19%, while grain harvested in late October or early November could have the highest moisture content, about 24% and not spoil before dry.
  4. There are three ways in which grain is typically loaded into low temperature bin dryers, and each works when adapted to specific operation needs: single filling, layered filling, and controlled filling. In single filling, the bin is filled at the rate of harvest. Layered filling involves loading the bin at a specific height per length of time, for example, 1/4 bin depth per week. In controlled filling, grain is loaded into the bin according to its moisture content and grain drying progress. Layered or controlled filling reduces drying times compared to single fill and reduces the risk of spoilage. Grain should be screened to remove fines and a grain spreader is highly recommended when filling to evenly distribute fines in the bin and reduce storage problems. Grain is dried and stored in the same bin which reduces handling. Adding low temperature heat does not reduce the amount of air flow required to dry grain, although adding heat can decrease drying times up to 45%.
  5. Low temperature bin dryers are more energy efficient than continuous flow and high temperature batch bin dryers, but may cost more to operate depending on electricity costs. As drying occurs in the bin, the bottom layer will be over-dried in order to get the grain above it dry. Over-drying reduces energy efficiency. Stirring mechanisms pull some of the dry grain off the floor and allow higher moisture grain from above to replace it. Stirring mechanisms can increase air flow by 1/3 and increase the energy efficiency of low temperature bin dryers by 20% to 25%.
2. Continuous flow in-bin dryers
  1. A continuous-flow in-bin grain dryer is an automated high-temperature bin dryer that contains a perforated floor, grain spreading device, sweep auger, automated control system and grain unloading equipment. LP gas or natural gas is used for a heat source for drying. The dryer can be loaded with grain to a depth of 3 to 9 feet and wet grain is placed on top of the drying grain, eliminating the need for wet bins. As the heated air rises through the grain during drying, it picks up moisture and preheats the wet grain. The automated control system periodically senses the grain moisture and if the grain is dry, the sweep auger removes a layer of dry grain from the bin floor. Grain is unloaded intermittently as it dries, and is transferred to storage bins while still hot, where it is cooled (in-bin cooling).
  2. When compared to other high temperature dryers, continuous flow in-bin dryers are among the highest in energy efficiency for high temperature dryers. Ambient air or low temperature bin dryers are more energy efficient but continuous-flow in-bin dryers usually cost less to operate because of lower energy costs. Dryeration can be used with continuous-flow in-bin dryers instead of in-bin cooling and reduce energy costs by an additional 10 to 15%.
3. Dryeration
  1. Dryeration is a steeping process that allows the moisture in the grain kernel to equalize before cooling. The process can be used with any high temperature dryer, continuous or batch, and is advantageous because it can reduce energy costs by up to 25% and reduce stress cracking and kernel breakage. This process involves drying the grain down to 2.0 to 3.0 percent points of moisture content above the final storage moisture, transferring the grain while hot into a steeping bin, and allowing the grain to steep for four to twelve hours before aeration fans are turned on. The dryeration bins need fan capacity of 0.5 to 1.0 cfm per bushel depending on how fast the grain needs to be cooled.
  2. After the grain is cooled and dried, it must be moved from the steeping bin to prevent spoilage from moisture that condenses on the bin walls. Typically two steeping bins are used so harvesting can proceed continuously. While one bin is being filled the second bin is steeping, cooling and being emptied. This process can save 15% to 25% of energy costs, and increase drying capacity by 50% to 70%. The exception is high-temperature batch-bin and continuous-flow in-bin dryers which will reduce energy costs by about 10% and increase drying capacity by about 35%.

Give students 10 minutes to review the information and make their comparisons. Circulate the room and answer questions as needed. Have students present their response to the question “Which method of drying grain would you recommend and why?”

Objective 3: Identify practices in raising livestock where energy conservation and efficiency could be realized.

There are numerous ways to conserve energy and be more energy efficient in livestock operations as well. Present the following information to students and have them capture the information in their notes.

Hog Operations:
1. Heat Lamps
  1. Change to lower wattage heat lamps during summer months.
  2. Avoid long drop cords and poor connections.
  3. Check and adjust lamp heights for maximum efficiency and safety.
2. Ventilation: When heating and venting, monitor thermostats & keep controls clean.
3. Heat Pad: Keep mats as clean as possible.
Dairy Operations:
1. Dairy Water Heater: Efficient water heaters can save up to 4900 kWh on a 30-cow farm.
2. Feed Mill: Add rodent guards to open motors and keep motors clean for efficient use and longer life.
3. Milk Cooler: Efficient milk coolers can save up to 23,500 kWh on a 400-cow farm. Use reclaimed heat from bulk coolers for heating water.
4. Milking Machine: Efficient vacuum pumps can save up to 1700 kWh on a 30-cow farm.
5. Silo Unloader: Avoid overloading and follow manufacturer's instructions.
Poultry Operations:
1. Cleaning/Collecting
  1. Stagger operate or rotate use of multi-motor operations.
  2. Small horsepower conveyors are more efficient than large ones operating for short periods.
2. Lighting
  1. Regularly turn off lights when they are not needed.
  2. Light only work areas rather than entire buildings.
  3. Keep lamps, tubes, reflectors, and lenses clean.
  4. Consider fluorescent lighting instead of incandescent lighting.
  5. Install mercury vapor or sodium vapor lamps for large exterior or high-bay interior areas.
3. Processing
  1. Be sure that controls allow proper cycling of the cool storage system.
  2. In egg-packing areas, dehumidification can be accomplished with a heat pump or by adding a heat recovery system to the AC. The reclaimed heat can be used for the water heating system.
4. Ventilation
  1. When rooms or buildings need both heat and ventilation, check thermostats frequently to assure efficient operation.
  2. Keep the controls clean.

Review:

Use the student learning objectives to summarize the lesson. Review by playing a game of Jeopardy.

Prior to class the instructor should determine categories for questions. Suggestions include Livestock, Grain, Tillage, Etc.. Using these, or other categories determined by the instructor, have students write facts from the lesson on 3x5 cards.

On a separate sheet of paper, have students write an appropriate question for each fact card created. Question writing primes students for the game. The instructor should then gather the fact cards by category and remove duplicates. Review the procedure for playing “Jeopardy” and make any modifications needed for your classroom. Finally, before playing, group students into teams.

Instructor should assist students in creating fact cards. Once students are finished creating fact cards, collect by category and review the procedure for playing Jeopardy.

Instructor will serve as the host and students will work in teams. All answers will be of equal value. Teams will gain control of the board by providing a correct question to an answer. Teams will ring in by having one person in the group raise their hand. Each person in the group must take a turn before another person can go a second time. Remember, you will respond with a question to each fact given.

As students provide answers to questions, take time to clear up any misunderstandings about the content. The instructor can keep score or groups can keep score. The instructor may wish to award a prize for the team with the most points at the end. The instructor can make the game more entertaining by taking on characteristics of the host. To determine which group goes first, have groups guess a number, flip a coin, or determine through “rock, paper, scissors”.

Worksheet Key:

1,390 gallons
$534
$147 (1,469 gallons * $0.10)
$6,379
$3,274
$3,756, $2,796
$960
966 gallons

Essential Files (maps, charts, pictures, or documents)

Extension Activities

Conduct a basic energy audit of your home or farm. Keep a checklist of problems you find, as it will help you prioritize upgrades and fixes.

Sources/Credits

http://agenergyia.org/

Author(s)