Agricultural engineering

INTRODUCTION TO SURVEYING

What is Surveying?

·  Art of determining positions of objects on Earth by measuring distances and preparing maps.

Classification of Surveying

Primary Classification

Plane Surveying: Earth considered flat; for small areas (<250 km²).

Geodetic Surveying: Earth’s curvature considered; for large areas (>250 km²).

Secondary Classification

Based on Instruments

·  Chain, Compass, Plane table, Theodolite, Tacheometric, Photographic surveys

Based on Methods

·   Triangulation, Traverse surveys

Based on Object

·   Geological, Mine, Archaeological, Military surveys

Based on Nature of Field

·    Land (Topographical, Cadastral, City, Engineering), Marine, Astronomical surveys

Types of Engineering Surveys

·     Reconnaissance (feasibility)

·     Preliminary (precise data, best location)

·     Location (setting out work)

Survey Equipment

Chain–Cross Staff Survey

·  Chain, Tape, Cross staff, Ranging rod, Offset rods, Arrows

Compass Survey

·  Prismatic compass, Chain, Ranging rod

Plane Table Survey

·  Plane table (with tripod), Telescopic alidade, Trough compass, 'U' frame with plumb bob, Spirit level, Chain, Ranging rod, Dumpy level with stand, Metric staff

CHAIN AND CROSS STAFF SURVEYING

Principle of Chain Surveying

Ø  Based on triangulation: area divided into triangles, sides measured directly with chain or tape, no angles measured.

Ø  Suitable for small, level areas where triangles can be easily formed.

Instruments Used

Ø  For measuring distances: Chain, Tape

Ø  For marking stations: Ranging rod, Offset rod, Pegs

Ø  For setting right angles: Cross staff, Optical square

Ø  Other: Arrows, Plumb bob

Types of Chains

Metric chain: 20 m (100 links) or 30 m (150 links), each link 0.2 m, tallies/brass rings for easy reading

Gunter’s chain: 66 ft, 100 links, used for land in acres

Revenue chain: 33 ft, 16 links, used in cadastral survey

Engineer’s chain: 100 ft, 100 links, used in engineering surveys

Tapes (Types)

Cloth/linen, Metallic, Steel, Invar, Synthetic material

Ranging Rods

Wooden/steel, painted for visibility, 2 m or 3 m, pointed end, used for marking points and ranging lines

Arrows

Tempered steel, one end with ring, other pointed, used for counting chain lengths

Cross Staff

Sets right angles on chain line; types: Open, French, Adjustable; open type most common

COMPASS SURVEYING

Compass Surveying

Definition

Compass surveying is a branch of surveying where the directions (bearings) of survey lines are determined using a magnetic compass, and the lengths of these lines are measured using a chain, tape, or laser range finder.

Principle

         The principle of compass surveying is based on traversing, which involves surveying a series of connected lines (called traverse legs) by measuring their magnetic bearings with a compass and their lengths with a chain or tape

Materials required

Ø  Prismatic compass

Ø  Surveyor's Compass

Ø  Measuring Tape or Chain

Ø  Ranging Rods

Ø  Tripod Stand

Ø  Plumb Bob

Ø  Cross Staff

Ø  Arrows

Methodology

Radiation Method

Ø  Choose a central station point (O).

Ø  Sight the compass toward each boundary station (A, B, C, etc.) by aligning the sighting vane and prism with the ranging rods placed at those points.

Ø  Record the magnetic bearing of each line from O to the boundary points.

Ø  Measure the distances from O to each boundary point using a chain or tape.

Intersection Method

Ø  Select two fixed points (P and Q) outside or inside the field such that all boundary points are visible from these stations.

Ø  Set the compass at station P, measure bearings to all boundary points and the fore bearing of line PQ.

Ø  Move the compass to station Q, measure bearings to the boundary points and back bearing of QP.

Ø  Measure the baseline distance PQ.

Ø  No need to measure internal distances in this method.

Advantages

Ø  Simplicity and Ease of Use

Ø  Cost-Effectiveness

Ø  Portability

Ø  Quick Setup and Operation

Ø  Independent Line Measurements

Ø  No Power Required

Ø  Suitable for Large and Obstructed Areas

Limitations

Ø  Susceptibility to Magnetic Interference

Ø  Limited Accuracy

Ø  Magnetic Declination and Variation

Ø  Instrumental Errors

Ø  Cannot Measure Angles Directly

Ø  Distance Measurement Requires Separate Tools

Application

Ø  Boundary Surveys

Ø  Route Planning

Ø  Forestry

Ø  Archaeological Surveys

Ø  Navigation

Ø  Surveying Large or Undulating Areas

Ø  Time-Sensitive Surveys

Errors in Compass Surveying

Ø  Instrumental Errors: Faulty compass parts, misalignment, sluggish needle, etc.

Ø  Personal Errors: Mistakes by surveyor (e.g., poor centering, reading errors).

Ø  Natural Errors: External influences.

Prismatic Compass

Ø  Measures magnetic bearings.

Ø  Graduations on an aluminum ring attached to the needle.

Ø  Readings taken through a prism for magnification and accuracy.

Levelling: Make the needle horizontal using the ball and socket joint.

Definition

Leveling: Determining relative heights (altitudes) of points on Earth’s surface.

Key Terms

Ø  Bench Mark (BM): Reference point with known elevation.

Ø  Datum: Reference level surface (often assumed or mean sea level).

Ø  Reduced Level (RL): Elevation of a point relative to datum.

Ø  Line of Collimation: Imaginary line through the instrument’s cross-hairs and optical center.

Ø  Station: Point where leveling staff is held.

Ø  Height of Instrument (HI): Elevation of the line of sight above datum.

Ø  Back Sight (BS): Reading on a known elevation point (to establish HI).

Ø  Fore Sight (FS): Reading on an unknown point (to determine its RL).

Ø  Change Point: Point where both FS and next BS are taken.

Types of Bench Marks

1. GTS Bench Mark: Established by national agencies, highly accurate.

2. Permanent Bench Mark: Fixed with reference to GTS BM.

3. Arbitrary Bench Mark: Assumed elevation, used for local projects.

Instruments in Leveling

Ø  Dumpy Level: Main instrument for leveling.

Ø  Tripod Stand: Supports the level.

Ø  Leveling Staff: Graduated rod for vertical measurements (usually 4 m long, smallest division 5 mm).

Ø  Bubble Tubes: Ensure the instrument is level.

Ø  Foot Screws: For fine adjustment of instrument level.

Soil Erosion

Definition

Wearing away, detachment, transportation, and deposition of soil by water, wind, or other causes.

Types of Erosion

Geological Erosion

Natural, slow, balanced by soil formation.

Accelerated Erosion

Ø  Caused by human activities like cultivation, overgrazing.

Ø  Disturbs natural soil binding.

Forms of Water Erosion

Ø  Splash/Rain Drop Erosion: Soil particles splashed by raindrops.

Ø  Sheet Erosion: Thin layer removal over large area, hard to detect.

Ø  Rill Erosion: Small channels formed by concentrated runoff.

Ø  Gully Erosion: Large channels that cannot be smoothed by tillage.

Gully Development Stages

Ø  Formation (downward scour)

Ø  Development (headward erosion)

Ø  Healing (vegetation growth)

Ø  Stabilization (stable slopes and cover)

Wind Erosion

Definition

Soil particles detached and transported by wind.

Conditions Accelerating Wind Erosion

Ø  Loose, dry, fine soil

Ø  Bare, smooth soil surface

Ø  Strong winds

Mechanics of Wind Erosion

Ø  Detrusion: Direct wind impact detaches particles.

Ø  Extrusion: Particles hit soil and dislodge more particles.

Ø  Efflusion: Fine particles lifted and transported in air.

Particle Movement Types

Ø  Suspension: Fine particles carried in air.

Ø  Saltation: Particles bounce along surface.

Ø  Surface Creep: Heavy particles pushed along surface.

Vegetative (Biological/Agronomic) Measures for Erosion Control

What Are They?

Ø  Methods using crops, vegetation, tillage, and land/water management to reduce soil erosion.

Ø  Suitable for land with slopes up to 2%.

Main Vegetative Measures

Strip Cropping

Ø  Growing erosion-permitting and erosion-resisting crops in alternate strips.

Ø  Erosion-permitting crops: Cotton, jowar, bajra.

Ø  Erosion-resisting crops: Groundnut, matki, hulga, soybean.

Types of Strip Cropping:

1. Contour Strip Cropping: Strips follow land contours.

2. Field Strip Cropping: Strips of uniform width, not necessarily on contour.

3. Buffer Strip Cropping: Grass/legume strips between crop strips.

4. Wind Strip Cropping: Strips at right angles to prevailing wind.

Mulching

Ø  Applying plant residues (e.g., stubble, straw, sawdust) on soil surface.

Ø  Conserves moisture, reduces runoff and erosion.

Ø  Typical application: ~5 tonnes/ha.

Crop Rotation

Ø  Growing different crops in succession on the same land.

Ø  Reduces erosion compared to continuous single-crop farming.

Ø  Legumes (e.g., hulga, matki, gram) after cereals help cover soil.

Contour Cultivation

Ø  Tillage and planting across the slope (along contours), not up/down.

Ø  Rows act as small bunds, slowing water flow and reducing erosion.

Planting Grasses on Bunds

Ø  Grasses stabilize bunds, prevent erosion, and improve soil.

Ø  Examples: Anjan, marvel-8, rhodes, thin napier, blue panic, kusal.

Planting Trees/Afforestation

Ø  Forests and trees reduce runoff, increase organic matter, and conserve soil and water.

Shifting Cultivation

Ø  Temporary clearing for crops, then allowing land to recover by regrowth.

Ø  Cycle returns to original plot after a few years.

SOIL EROSION CONTROL ‐ MECHANICAL MEASURES

Mechanical Measures Overview

Ø  Used to control and prevent soil erosion, especially on agricultural lands.

Ø  Supplement biological methods (like planting cover crops).

Ø  Main types: contour bunds, graded bunds, terracing, contour stone walls.

Bunding

Construction of embankments (bunds) across slopes.

Types:

1.      Contour Bunds: Built along contour lines (constant elevation).

2.      Graded Bunds: Built with a slight slope (0.1%–0.3%) to direct excess water to outlets.

Contour Bunding

Ø  Bunds are constructed across the slope on contour lines, breaking long slopes into smaller sections.

Ø  Acts as a barrier, slowing water flow, increasing infiltration, and reducing runoff and soil erosion.

Ø  Suitable for low rainfall areas (<600 mm/year), especially on light-textured, red soils with 2–6% slope.

Ø  Not suitable for shallow or black cotton soils.

Graded Bunds

Ø  Used in medium to high rainfall areas, especially on clay soils.

Ø  Have a gentle slope (0.2%–0.35%) towards outlets to drain excess water and prevent waterlogging.

Ø  Spacing of Bunds

What is Bench Terracing?

Ø  Bench terracing: Construction of step-like fields along the contour by cutting and filling the slope.

Ø  Converts steep slopes into level fields, eliminating erosion hazards.

Ø  Retains manure and fertilizers, improves water management.

Ø  Suitable for slopes between 16% and 33%.

Types of Bench Terraces & Their Uses

Level Bench Terrace

Ø  Completely level, like a table top.

Ø  Used for paddy fields to ensure uniform water impounding.

Ø  Also called table top or paddy terraces.

Inward Sloping Bench Terrace

Ø  Surface slopes inward, towards the hill.

Ø  Used for crops sensitive to waterlogging (e.g., potato).

Ø  Has a drain on the inner side to quickly remove excess water.

Ø  Suitable for steep slopes.

Outward Sloping Bench Terrace

Ø  Surface slopes outward, away from the hill.

Ø  Often an intermediate stage in terrace construction.

Ø  Used in low rainfall or shallow soil areas.

Puertorican or California Type Terrace

Ø  Developed gradually by moving soil downhill during each ploughing.

Ø  Uses vegetative or mechanical barriers along the contour.

Ø  Terraces form over several years through natural leveling.

Broad Base Terrace

Ø  Definition: Wide embankment/channel built across slopes to reduce runoff, control erosion, and conserve moisture.

Ø  Features: Ridge height 25–50 cm, width 5–9 m, gentle slopes, channel on upper side.

Types: Graded (channel) and leveled (ridged).

Narrow Base Terrace:

  Similar, but narrower (1.2–2.5 m wide), used on steeper slopes (6–10%).

Contour Stone Wall

Ø  Construction: Dry-packed stones (~20 cm) across hill slopes (10–16%+ slope).

Ø  Spacing: 10–15 m apart, slight longitudinal slope (0.2%) towards outlet.

Ø  Purpose: Controls erosion, conserves moisture, and can help form bench terraces.

Broad Bed and Furrow (BBF) System

Ø  Description: Alternating broad beds (150 cm) and furrows (30 cm) for drainage and erosion control.

Ø  Use: Deep black soils with drainage problems (monsoon).

Basin Listing

Ø  Method: Creates a series of basins using a ‘Basin Lister’ implement.

Ø  Effect: Slows runoff, forms pockets to trap water, reduces erosion.

Ø  Efficiency: Covers 2–3 acres/day in heavy soils.

Tied Ridging

Ø  Method: Closely spaced ridges in two directions, forming rectangular basins.

Ø  Purpose: Retains rainwater for infiltration, best for permeable soils and level ground.

Ø  Design: Ties are lower than ridges to control overflow direction.

Gully Control Structures

Temporary Structures:

Ø  Types: Brushwood, loose rock, rock fill, woven wire dams.

Ø  Purpose: Slow water, trap sediment, aid vegetation growth.

Permanent Structures:

Ø  Purpose: Long-term gully protection and water storage.

Ø  Requirements: Durable materials, adequate capacity, stabilizes and stores water.

Pump – Definition

    A pump is a mechanical device used to move fluids (liquids or gases) from one place to another, typically by converting mechanical or electrical energy into hydraulic energy

Types of Pumps

Positive Displacement Pumps:

Ø  Define- A positive displacement pump is a type of pump that moves fluid by trapping a fixed volume of the fluid and mechanically forcing (displacing) that volume into the discharge pipe or system during each cycle of operation

Ø  Physically displace water using piston, plunger, gears, etc.

Reciprocating Pump: Piston moves in cylinder; suitable for high head.

Variable Displacement (Roto Dynamic) Pumps: Discharge decreases as head increases.

Centrifugal Pump: Uses rotating impeller; main type for irrigation.

Turbine, Propeller, Jet, Air Lift Pumps: Other types.

Centrifugal Pump (Details)

Operation: Impeller throws water outward by centrifugal force.

Selection: Based on head-capacity, efficiency, and power curves.

Priming: Must be filled with water before starting (unlike positive displacement pumps).

What is Farm Mechanization?

Definition: Use of engineering and technology in agriculture to improve productivity and efficiency.

Sources of Farm Power

I. Mobile Power

Ø  Human: Men, women, children (avg. 60W for men, 48W for women, 30W for children)

Ø  Draught Animals: Bullocks, buffaloes, camels, horses, donkeys (main source on 60% of cultivated area)

Ø  Bullocks: 10–14% of body weight as draft

Ø  Pair of bullocks: ~750W (1 hp)

Ø  Tractors: Main source for timely operations; India is 2nd largest tractor producer

Ø  Most tractors: 31–40 hp range

Ø  Power Tillers: 8–12 hp, used for small farms

Ø  Self-Propelled Machines: Combines, reapers, sprayers, etc.

II. Stationary Power

Ø  Diesel/Oil Engines: Used for pumps, threshers, etc.

Ø  Diesel efficiency: 32–38%

Ø  Electric Motors: Used for pumps, processing, etc.

Ø  Clean, quiet, low operating cost

III. Renewable Energy

Ø  Solar, wind, biomass

Ø  Used for lighting, cooking, water heating, power generation

Ø  Farm Power Availability & Productivity

Ø  1000 ha needs: 500 bullock pairs OR 167 power tillers OR 67 tractors

Ø  Only a few states have enough power for timely operations

Ø  Future: More mechanical/electrical power, less animal/human power

TWO STROKE AND FOUR STROKE ENGINES, WORKING PRINCIPLES, APPLICATIONS – TYPES, POWER AND EFFICIENCY.

Heat Engines

Heat engine: Converts heat from burning fuel into mechanical work.

Types:

1. External Combustion Engine: Fuel burns outside the cylinder (e.g., steam engine).

2. Internal Combustion Engine (IC Engine): Fuel burns inside the cylinder (e.g., petrol, diesel engines).

Internal Combustion (IC) Engine: Principle & Working

Principle: Fuel-air mixture is ignited inside a closed cylinder, creating high-pressure gases that push a piston. The piston’s motion turns a crankshaft, producing rotary motion.

Combustion Types:

1.      Constant Volume Combustion (CVC): Rapid explosion (spark ignition).

2.      Constant Pressure Combustion (CPC): Slow burning (compression ignition).

Four Stroke Cycle Engine

Completes cycle in 4 piston strokes (2 crankshaft revolutions)

Strokes:

1. Suction: Air/fuel enters through open inlet valve.

2. Compression: Piston compresses charge; both valves closed.

3. Power: Ignition causes expansion, piston moves, power delivered.

4. Exhaust: Burnt gases expelled through open exhaust valve.

Features: Has valves, larger flywheel, higher efficiency, even torque.

Two Stroke Cycle Engine

Completes cycle in 2 piston strokes (1 crankshaft revolution)

Process:

1. First Stroke (Suction + Compression): Piston moves up, compresses charge in cylinder, draws fresh mixture into crankcase.

2. Second Stroke (Power + Exhaust): Piston moves down, burnt gases exit, fresh mixture enters cylinder.

Features: No valves (uses ports), smaller flywheel, lighter, more power per weight, lower efficiency, more fuel consumption, scavenging needed.

DIFFERENT SYSTEMS OF IC ENGINE – COOLING, LUBRICATING,

FUEL INJECTION SYSTEMS

Main Components of IC Engine

Ø  Cylinder: Main chamber where combustion occurs and piston moves.

Ø  Cylinder Block: Main body, includes cylinder and cooling passages.

Ø  Cylinder Head: Covers cylinder, contains combustion chamber, spark plug, valves.

Ø  Cylinder Liner/Sleeve: Replaceable lining inside cylinder (dry or wet type).

Ø  Piston: Moves up and down, transmits force to crankshaft.

Ø  Piston Head (Crown): Top of piston.

Ø  Piston Skirt: Lower part, absorbs side forces.

Ø  Piston Rings: Seals gases, reduces friction, controls oil (types: compression and oil rings).

Ø  Piston Pin (Wrist/Gudgeon Pin): Connects piston to connecting rod.

Ø  Connecting Rod: Transfers motion from piston to crankshaft.

Ø  Crankshaft: Converts reciprocating motion to rotary motion.

Ø  Flywheel: Maintains smooth engine speed.

Ø  Oil Sump: Stores lubricating oil.

TRACTORS- TYPES AND UTILITIES

What is a Tractor?

Ø  A tractor is a self-propelled vehicle with wheels or tracks, used to operate agricultural implements, machines, and trailers.

Ø  The tractor engine powers both moving and stationary farm machinery via Power Take Off (PTO) or belt pulley.

Types of Tractors

Wheel Tractor

Ø  Most common, runs on wheels.

Ø  Used for general farm work.

Crawler Tractor

Ø  Moves on tracks.

Ø  Suitable for soft, wet, or unstable soils.

Power Tiller

Ø  Two-wheeled, hand-guided.

Ø  Used mainly in rice fields and small farms (5–12 kW).

Standard Row Crop Tractor

Ø  Designed for row crops.

Ø  Allows quick attachment of various implements.

Ø  High Clearance Tractor

Modified row crop tractor.

Ø  Extra clearance for tall crops (e.g., sugarcane).

Utility Tractor

Ø  Lower clearance, multipurpose.

Ø  Often used with front loaders for tasks like feedlot cleaning.

Orchard Tractor

Ø  Lower height, used in orchards.

Ø  No roll-over protection structure (ROPS).

Ø  Multipurpose TractorCan operate in both directions.

Ø  Carries and powers implements.

Lawn and Garden Tractor

Ø  <15 kW power, for lawn care.

Ø  Can tow/carry various attachments.

Tree Skidder Tractor

Ø  Four-wheel drive.

Ø  Used to move logs in forestry.

Skid Steer Loader Tractor

Ø  Compact, can turn in tight spaces.

Ø  Used in confined areas like dairies.

Four Wheel Drive Tractors

Ø  With smaller front wheels: Standard/row crop tractors with driven front wheels.

Ø  With equal sized wheels (Articulated): More power, steered by pivoting in the center.

Tractor Ratings

Rated by horsepower (drawbar and belt).

Ø  Small: as low as 10 hp (7.5 kW)

Ø  Large: up to 132 hp (98 kW) drawbar, 144 hp (107 kW) belt.

Tractor Components & Functions

Ø  Engine – Converts fuel to mechanical energy.

Ø  Clutch – Connects/disconnects engine from gearbox.

Ø  Gear Box – Provides different speeds and torque.

Ø  Differential – Allows rear wheels to rotate at different speeds during turns.

Ø  Final Drive – Reduces speed, increases torque to wheels.

Ø  Steering Mechanism – Turns front wheels.

Ø  Hydraulic Control – Lifts/lowers implements.

Ø  Hitch System – Connects implements (3-point hitch, drawbar).

Ø  Brakes – Stops tractor; independent brakes for sharp turns.

Ø  PTO (Power Take Off) – Drives rotary implements (rotavator, pumps).

Ø  Belt Pulley – Runs stationary equipment.

Ø  Electrical System – Battery, starter, lights, horn.

Ø  Radiator & Cooling System – Prevents engine overheating.

Ø  Lubricating System – Reduces friction/wear, cools and cleans engine parts.

Ø  Tyres – Provide traction.

Ø  Control Panel – Displays gauges (temperature, oil pressure, speed, etc.).

Cooling System

Uses water/radiator to remove engine heat.

Lubrication System

Ø  Purpose: Reduce friction, cool, clean, seal, and protect engine parts.

Ø  Types: Splash, force-feed, combination.

Fuel System

Delivers fuel from tank to engine, filters and injects at correct pressure.

Hitch and Hydraulics

Ø  Three-point hitch: For mounting implements.

Ø  Drawbar: For trailing implements.

Hydraulic system: Lifts and lowers implements.

SECONDARY TILLAGE EQUIPMENTS

What is Secondary Tillage?

Definition: Lighter, finer tillage operations after primary tillage to create proper soil tilth for seeding/planting.

Implements: Harrows, cultivators, levellers, clod crushers, etc. (tractor or animal drawn)

Harrows

Purpose: Cut, smooth, and pulverize soil, cut weeds, mix materials.

Types:

Ø  Disc Harrow: Rotating concave discs cut and invert soil. Good for hard, grassy ground.

Single Action: Two gangs, throw soil in opposite directions.

Double Action: Two sets of gangs; field is worked twice per trip.

Tandem: Four gangs, angled oppositely.

Offset: Two gangs, can be shifted left/right for orchards/gardens.

Ø  Spike Tooth Harrow: Peg-shaped teeth break clods, uproot weeds, level soil.

Ø  Spring Tooth Harrow: Flexible, springy teeth for hard/stony soils, kills weeds.

Ø  Acme Harrow: Curved knives, good for pulverizing and mulching.

Ø  Patela: Wooden plank with steel hooks, levels, packs, and uproots weeds.

Ø  Triangular Harrow: Triangular frame with fixed spikes.

Ø  Blade Harrow (Bakhar/Guntaka): Shallow working, minimal soil inversion, prepares seedbed in clayey soils.

Ø  Reciprocating Power Harrow: PTO-driven, oscillating arms break clods, fine tilth.

Land Forming Equipment

Ø  Bund Former: Makes ridges/bunds to hold water and conserve moisture.

Ø  Parts: Forming board, beam, handle.

Ø  Soil Scoop: Excavates ditches, moves soil short distances.

Ø  Parts: Blade, soil trough, hitch loop, handles.

Ø  Ridger: Forms ridges/channels for row crops, also called double mould board plough.

Ø  Parts: Beam, clevis, frog, handle, mould boards, share.

Wet Land Equipment

Ø  Puddler: Churns soil with water for paddy fields, reduces water loss, kills weeds, softens soil for transplanting.

Ø  Parts: Frame, puddling unit (blades), axle, cross beam, handle.

Ø  Helical Bladed Puddler: Blades fixed helically for better slicing, less jerking to animals, used after initial ploughing.

Leveller

Ø  Levels land for better irrigation, drainage, and mechanization.

Ø  Animal-drawn, consists of a wooden board and handle.

Green Manure Tramplers

Used to trample and press green manure into the soil (no inversion).

Types:

1.      Slat Type: Steel blades mounted on discs.

2.      Disc Type: Flat discs on a rotating shaft.

Cage Wheels

Ø  Special wheels fitted to tractors for wetland operations (like puddling).

Ø  Provide better traction in muddy fields.

Seed Drill

Definition: Machine for placing seeds in furrows at uniform rate, depth, and spacing, with or without covering.

Seed-cum-Fertilizer Drill

Ø  Has separate compartments for seeds and fertilizers.

Ø  Sows seeds and applies fertilizer simultaneously.

Seed Drill vs. Seed Planter

Seed Drill: Drops seeds in a continuous stream, spacing between plants is not fixed.

Seed Planter: Drops seeds at fixed intervals, precise plant-to-plant spacing.

SPRAYERS AND THEIR FUNCTION – CLASSIFICATION-MANUALLY OPERATED SPRAYERS-POWER OPERATED SPRAYER -  DUSTERS – TYPES AND USES.

Sprayers: Purpose & Functions

Purpose: Apply fluids (herbicides, fungicides, insecticides, micronutrients) as droplets to plants.

Basic Components of a Sprayer

Nozzle body, swirl plate, filter, overflow pipe, relief valve, pressure regulator, cut-off valve, spray boom, drop legs, nozzle boss, nozzle disc, nozzle cap, nozzle tip, spray lance, spray gun.

Types of Spray (by Volume)

1.      High Volume: >400 L/ha (dilute, hydraulic machines)

2.  Low Volume: 5–400 L/ha (uses air stream, saves material)

3.      Ultra Low Volume (ULV): <5 L/ha (motorized, spinning disc)

Classification of Sprayers

Manually Operated Sprayers

Ø  Hand Atomizer: Small container, hand pump, nozzle. (18–45 L/acre)

Ø  Bucket Sprayer: Pump placed in bucket of spray liquid.

Ø  Hand Compression Sprayer: Tank (6–18 L), air pump, spray lance.

Ø  Knapsack Sprayer: Tank (10–20 L), worn on back, pump lever, lance.

Ø  Rocker Sprayer: Pump, pressure chamber, separate tank, high pressure (14–18 kg/cm²).

Ø  Foot/Pedal Sprayer: Pedal-operated plunger, high pressure (17–21 kg/cm²).

Power Operated Sprayers

Ø  Motorized Knapsack Sprayer: Petrol engine (1.2–3.0 hp), tank (10–12 L), air blower, adjustable discharge, for large areas and tall crops.

Ø  Tractor-Mounted Sprayer: Large tank, boom with multiple nozzles, for field crops.

Key Components of Power Sprayers

Prime mover (engine), tank, agitator, air chamber, pressure gauge, pressure regulator, strainer, boom, nozzles.

Types of Nozzles

Ø  Hollow Cone: Fine droplets, good coverage (fungicides/insecticides).

Ø  Solid Cone: Full area coverage at short range.

Ø  Fan Type: Flat, fan-shaped spray, used for herbicides.

Care of Power Sprayer

Check oil, grease, hose tightness, strainer, and V-belts before use.

Dusters

Purpose: Apply dry powdered chemicals (e.g., insecticides, fungicides).

Types:

1.      Hand Rotary Duster: Blower, gearbox, hopper, crank-operated.

2.      Power Duster: Engine-driven, large areas.

HARVESTING TOOLS AND EQUIPMENT – SICKLES-PADDY REAPER AND COMBINE- HARVESTING MACHINERY FOR GROUNDNUT-TUBER CROPS AND SUGARCANE HARVESTER

What is Harvesting?

Ø  Definition: Cutting, picking, plucking, or digging to remove crops (above or below ground) or useful parts/fruits from plants.

Ø  Harvesting Actions: Slicing, tearing, high-velocity impact, scissors action.

Ø  Methods: Manual tools, animal-drawn machines, mechanical machines.

Manual Harvesting Tool

Sickle

Ø  Parts: Curved steel blade (plain or serrated), wooden handle, tang, ferrule.

Ø  Use: Harvesting crops, cutting vegetation.

Ø  Type: Plain (smooth edge) or serrated (teeth for tough crops).

Ø  Limitations: Labor-intensive, slow.

Mowers (For Herbage/Grass)

Ø  Cylinder Mower: Rotating helical blades (continuous cut).

Ø  Reciprocating Mower: Knife sections reciprocate against fingers (most common).

Ø  Horizontal Rotary Mower: High-speed rotating knife (uniform cut).

Ø  Gang Mower: Multiple cylinder mowers assembled together.

Ø  Flail Mower: Swinging knives (horizontal plane/cylinder).

Paddy Reaper Harvester

Ø  Front mounted: Cutter bar, gathering headers, vertical conveyors, gearbox, cage wheels.

Ø  Operation: Cuts and windrows crop in straight lines.

Ø  Benefits: 75.5% cost saving, 64% time saving vs. manual; 5–6 acres/day.

Ø  Limitation: Not suitable for lodged crops.

Mini Paddy Combine

Ø  Components: Diesel engine, gear box, reaper unit, threshing unit, blower, straw reaper.

Ø  Operation: Cuts, gathers, conveys, threshes, and cleans paddy in one pass.

Ø  Field Capacity: 0.11 ha/hr.

Ø  Advantage: Suitable for various crop heights.

Combine Harvester

Ø  Functions: Cuts, threshes, separates, and cleans grain in one pass.

Ø  Key Specs:

Ø  Engine: 88 HP

Ø  Cutter bar width: 2300 mm

Ø  Thresher drum: 600 mm diameter, 765 mm length

Ø  Cleaning area: 710 x 1850 mm

Ø  Fully hydrostatic controlled transmission

Ø  Cutter Bar: Assembly with knife sections, guards, ledger plates, clips.

Ø  Alignment: Proper alignment and registration are crucial for efficient cutting.

Sugarcane Harvesters

Ø  Case New Holland (Brazil)

Ø  Type: Billet/Chopper

Ø  Power: 260 kW (353 hp)

Ø  Capacity: 20–30 tons/hr (max 60)

Ø  Row Spacing: ≥150 cm

Ø  Cost: ~Rs. 2 crore (with in-field trucks)

Bunmai/SMKY (Japan/Thailand)

Ø  Type: Billet/Chopper, rubber track mobility

Ø  Power: 100 kW (135 hp)

Ø  Capacity: 12–15 tons/hr (max 25)

Ø  Cost: ~Rs. 1.3 crore (with loader/trailer)

Hansen Machinery (China)

Ø  Type: Whole stalk, pneumatic wheels

Ø  Power: 194 kW (260 hp)

Ø  Capacity: 12–15 tons/hr (max 25)

Ø  Row Spacing: ≥120 cm

Ø  Cost: ~Rs. 1.43 crore (with loader/trucks)

Harvesters for Tuber Crops

Turmeric Harvester

Ø  Power Tiller Operated: Blade with bar points, oscillating slats, cage wheels.

Ø  Benefits: 65% cost, 90% time saving; 0.5% damage; 0.8% undug; 0.6 ha/day.

Ø  Tractor Operated: Blade with bar points, lift rods, adjustable rake angle.

Ø  Benefits: 70% cost, 90% time saving; 2.83% damage; 2.42% undug; 1.6 ha/day; cost ~Rs. 10,000.

Groundnut Harvesters

Ø  Power Tiller Operated

Ø  Components: Mainframe, tool, picker conveyor, depth wheels.

Ø  Capacity: 0.8 ha/day.

Ø  Tractor Drawn

Ø  Components: Soil loosening blade, pick-up conveyor, windrower.

Ø  Operation: Loosens soil, lifts and conveys crop, windrows for collection.

Capacity: 2 ha/day; 99% harvesting, 95% soil separation efficiency; 32% labor, 96% time saving; cost ~Rs. 20,000.

PROTECTED CULTIVATION AND SECONDARY AGRICULTURE

Protected cultivation: Modifying the plant’s environment (air and soil) to optimize growth, yield, and quality—essentially, controlled environment agriculture (CEA).

Why it is essential

           Protected cultivation is essential because it creates a controlled environment that protects crops from pests, diseases, and extreme weather, leading to higher yields and better-quality produce.

Key reasons why protected cultivation is essential include:

Ø  Protection from external threats

Ø  Efficient resource management

Ø  Improved crop quality and diversification

Ø  Sustainability

Scope

Ø  Climate Adaptation

Ø  Crop Quality and Yield

Ø  Off-Season and High-Value Crops

Ø  Pest and Disease Management

Ø  Resource Efficiency

Applicability

Ø  Horticultural Crops

Ø  Small to Large Scale Farming

Structures/components of Protected cultivation

Ø  High-tech Greenhouses: Fully climate-controlled, expensive, used for high-value crops.

Ø  Semi-climate Controlled: Partial control (fans, cooling pads); less expensive.

Ø  Naturally Ventilated/Low-cost: Simple, minimal climate control, affordable, widely used in China.

Greenhouse Technology – Definition, History, Advantages, and Limitations

Introduction

Ø  Greenhouse technology controls plant environment for better yield and quality.

Ø  Developed to protect crops from unfavorable weather.

Greenhouse Technology

Ø  Technique to grow crops in controlled conditions (temperature, humidity, light, etc.).

Ø  Allows cultivation of high-value crops in adverse climates.

Greenhouse Effect

Ø  Greenhouse traps solar energy, increasing inside temperature.

Ø  Beneficial for crop growth in cold regions.

Types of Greenhouses (Shape, Cost, Utility, Cladding Materials)

Classification

Ø  Greenhouses protect plants from extreme weather and pests.

Ø  Modify environment for optimal plant growth.

Based on Utility

1.  Active Heating: For cold climates; uses heaters, double glazing.

2.  Active Cooling: For hot climates; uses fans, cooling pads, large roof openings.

Based on Covering Materials

1.  Glass: High light, durable, expensive.

2.  Plastic Film: Cheap, easy to use, short lifespan (4 years).

3.  Rigid Panel: Polycarbonate, acrylic, fiberglass; durable, uniform light, can collect dust/algae.

Shading Nets

Ø  Used to create micro-climates for different crops.

Ø  Protect from UV, rain, wind, and temperature extremes.

Ø  Available in various shade percentages (30-90%).

Factors Affecting Plant growth in protected structures

Light

Ø  Essential for photosynthesis (growth & yield).

Ø  Too little light = slow growth; too much = chloroplast damage.

Ø  Light intensity measured in lux; optimal varies by crop.

Ø  Blue light: hard, dark plants. Red light: tall, soft plants. All visible light (400–700 nm) used in photosynthesis.

Temperature

Ø  Each crop has a preferred temperature range.

Ø  Too low: cell damage from ice. Too high: enzymes stop working.

Ø  Day temp should be 3–8°C higher than night temp.

Ø  Optimal night temps: 7–22°C depending on crop.

Relative Humidity (RH)

Ø  Greenhouses usually have higher RH than outside.

Ø  Ideal RH: 50–80% (up to 90% for propagation).

Ø  Controlled by humidification (fogging/cooling pads) or dehumidification (ventilation, dehumidifiers).

Ventilation

Ø  Needed to control temp, humidity, and CO₂.

Ø  Can be natural (small houses) or forced (fans for large/precise control).

Carbon Dioxide (CO₂)

Ø  Essential for photosynthesis; 40% of plant dry matter is carbon.

Ø  Ambient CO₂: ~345 ppm; plants benefit from enrichment (1000–1200 ppm).

Ø  Ventilation replenishes CO₂; enrichment used in cold climates.

Root Media

Ø  Must provide nutrients, water, aeration, and support.

Ø  Desirable properties: stable organic matter, good C:N ratio, proper bulk density, moisture retention, pH balance, high CEC.

Planning and Design of Greenhouses

Covering Materials

Ø  Factors: light transmission, weight, impact resistance, durability, thermal stability.

Ø  Lifespan:

Ø  Glass/acrylic: 20 years

Ø  Polycarbonate/fiberglass: 5–12 years

Ø  Polyethylene: 2–6 months (UV-stabilized: 2–3 years)

Glass Greenhouses

Ø  High light intensity, lower humidity (good for disease control).

Ø  Higher initial cost than plastic, but lasts longer.

Ø  Types: lean-to, even-span, ridge-and-furrow.

Pipe-Framed Greenhouses

Ø  Lower cost, long life; use GI pipes and UV-stabilized LDPE film.

Ø  Materials: GI pipes, sheets, rods, concrete, LDPE film, wood, bolts, etc.

Equipment and Components of a Greenhouse – Summer Cooling, Winter Cooling, Natural and Forced Ventilation.

Summer Cooling Systems

Active Summer Cooling

Ø  Purpose: Reduce excess heat inside greenhouse.

Ø  Methods:Fan-and-Pad System: Water runs through pads; fans pull air through wet pads, cooling it by evaporation.

Ø  Fog System: High-pressure pumps create fine fog; droplets evaporate and cool air without wetting plants.

Design Considerations

Ø  Air exchange rate: 3.4–5.2 m³/min/m² of floor area.

Ø  Factors affecting cooling: Elevation, light intensity, temperature rise, pad-to-fan distance.

Ø  Pad materials: Cross-fluted cellulose pads last longer than excelsior (wood fiber) pads.

Ø  Water requirements: Pads need continuous water supply; sump size depends on pad type.

Winter Cooling Systems

Active Winter Cooling

Ø  Purpose: Prevent overheating from solar gain in winter; mix cold outside air with warm inside air.

Ø  Methods:

Ø  Convection Tube System: Fans push cold air through perforated tubes, mixing it above plant height.

Ø  Horizontal Air Flow (HAF) Fans: Small fans circulate air in a circular pattern for even temperature.

Ø  Fan placement: At intervals along greenhouse; air flows parallel to ground, above plant height.

Design Considerations

Ø  Air exchange rate: 0.61 m³/min/m² of floor area.

Ø  Adjust for: Temperature difference, elevation, light intensity.

Materials for Construction of Greenhouses

1.      Wood & Bamboo

2.      Galvanised Iron (GI), Steel, Aluminium, RCC

3.      Glass

4.      Polyethylene Film

5.      Poly Vinyl Chloride (PVC) Film

6.      Tefzel T2 Film

7.      PVC Rigid Panels

8.      Fibreglass-Reinforced Plastic (FRP) Panels

9.      Acrylic & Polycarbonate Panels

Irrigation Systems in Greenhouses

Manual/Hand Watering

Overhead Irrigation System

Ø  Sprinkler Irrigation

Ø  Boom Irrigation

Surface Irrigation System

Ø  Drip irrigation

Ø  Perimeter watering system

Ø  Tube water system

Subsurface Irrigation System

Ø  Ebb and Flow System

Ø  Capillary Mat Watering System

Ø  Floor Flood Irrigation System

Ø  Water Trays and Saucers

Typical Applications of Greenhouses,Greenhouse Drying, Cost Estimation & Economic Analysis.

Applications of Greenhouses

Heating Systems

1. Passive Solar Greenhouse

Ø  Uses solar energy for heating; heat can be stored in water or rocks.

Ø  Reduces need for fossil fuel heating, especially in cold regions.

Ø  Heat losses occur by conduction (through materials), convection (air leaks), and radiation (infrared loss).

2. Hot Air Greenhouse Heating Systems

Ø  Unit Heater System: Heats air using fuel combustion; fans circulate warm air.

Ø  Central Heating System: Central boiler produces steam/hot water, distributed via pipes or coils.

Ø  Radiant Heating System: Gas burned in overhead pipes; heat radiates directly to plants and soil.

Ø  Solar Heating System: Uses solar collectors, heat stored in water/rock beds for later use; not widely used due to high cost.

Applications of GH

Ø  Year-round crop production

Ø  Extending growing seasons

Ø  Geothermal heating

Ø  Research and breeding

Ø  Specialized agriculture

Ø  Crop protection

Heat Distribution

Convection Tube: Warm air distributed via perforated tubes.

Horizontal Air Flow (HAF): Fans circulate air for uniform temperature.Greenhouse Drying (Off-season Use)

Ø  Greenhouses can be used as solar dryers for agricultural produce (e.g., tobacco curing, food drying).

Ø  Drying is faster, more hygienic, and can be controlled compared to open sun drying.

Ø  Greenhouse dryers combine solar collector and drying chamber; can be passive (natural convection) or active (with fans).

Types of Solar Dryers

1.      Tent Dryer: Simple frame with plastic sheet; protects from dust/rain, but easily damaged by wind.

2.  Box Dryer: Wooden box with transparent lid; black inside, mesh tray for product, airflow via holes.

3.      Solar Cabinet Dryer: Large box with trays; can be direct (transparent) or indirect (opaque); mixed-mode combines both.

Principles of Drying

Drying removes moisture by creating a vapor pressure difference between the product and air.

Types of Drying

1.      Sun/Solar Drying: Uses sunlight; traditional, low-cost

2.  Contact (Conduction) Drying: Heat supplied by direct contact (e.g., hot plates, cylinders)

3.  Convective Drying: Heated air passes over/through product (e.g., air dryers, recirculatory dryers)

4.      Radiation Drying: Uses electromagnetic (infrared) waves; good for thin layers

Drying Bed Types

1.      Thin Layer Drying: Grain layer ≤15 cm; all grains exposed to air

2.      Deep Bed Drying: Layer >15 cm; drying zone moves upward; risk of overdrying bottom layer

Dryer Performance

Ø  Thermal Efficiency: Heat used for evaporation / Total heat supplied

Ø  Heat Utilization Factor: 1 – coefficient of performance

Commercial Grain Dryers

Sun Drying

Ø  Methods: Standing crops, grains on stalk, threshed grains

Ø  Losses: Birds, insects, rodents

Mechanical Drying

Ø  Unheated/Natural Air Drying: Slow, uses ambient air

Ø  Supplemented Heating: Adds small heat to air

Ø  Heated Air Drying: Uses hot air for faster drying

Special Drying Methods

Ø  Freeze Drying: Sublimation of frozen water at low temp/pressure

Ø  Superheated Steam Drying: Uses water vapor for drying

Ø  Osmotic Drying: Uses solutions (e.g., sugar, salt) for moisture removal

Ø  Desiccated Air Drying: Air passed through desiccant (e.g., silica gel)

Types of Dryers

1. Deep Bed Dryer: Large capacity, thick grain layer

2. Flat Bed Dryer: Thin layer, quick and uniform drying

3. Continuous Flow Dryer: Grains move through dryer; mixing/non-mixing types

4. Recirculating Dryer: Grains pass through dryer multiple times, with tempering

5. LSU Dryer: Mixing type, high capacity, used for rice

6. Fluidized Bed Dryer: Hot air fluidizes grains for rapid, uniform drying

7. Rotary Dryer: Rotating drum, good mixing, used for grains and pulses

8. Spouted Bed Dryer: Air jet spouts grains, good for uniform drying

9. Tray Dryer: Trays stacked, used for vegetables, thin layers

10. Tunnel Dryer: Moving trays in a tunnel, continuous operation

11. Bag Drying: Grains dried in bags on racks with forced air

12. Solar Dryer: Uses solar-heated air for improved drying over sun drying

Material Handling – Screw Conveyor

Screw Conveyor

Ø  Construction: U-shaped or tubular trough, rotating shaft with helical screw

Ø  Working: Rotating screw moves grain along trough

Ø  Parts: Screw blade, shaft, trough, bearings, inlet/outlet, drive

Ø  Applications: Horizontal or inclined grain movement (capacity decreases with angle)

Ø  Capacity Factors: Diameter, pitch, speed, shaft diameter, loading

Belt Conveyor & Bucket Elevator

Belt Conveyor

Ø  Components: Endless belt, pulleys, idlers, drive mechanism

Ø  Operation: Product rides on belt; suitable for long, horizontal/low-incline transport

Ø  Belt Speed: 2.5–2.8 m/s for grains

Ø  Idlers: Flat or troughing (20°, 35°, 45°) for various materials

Ø  Discharge: Over end pulley or via tripper (fixed or movable)

Bucket Elevator

Ø  Construction: Buckets attached to belt/chain, runs vertically between head (top) and boot (bottom) sections

Ø  Types: Spaced bucket (centrifugal, positive discharge), continuous bucket

Ø  Parts: Head section, boot section, elevator legs, belts, buckets, drive mechanism

Ø  Operation: Buckets scoop product at boot, elevate, and discharge at head

Ø  Capacity Factors: Bucket size/spacing, speed, loading/unloading method

Ø  Drive Mechanism: Located at head, with motor, gearbox, couplings

Energy Source Classification

Ø  Primary: Found in nature (coal, oil, natural gas, biomass).

Ø  Secondary: Produced from primary (electricity, fuels).

Ø  Commercial: Sold for a price (electricity, coal, oil).

Ø  Non-commercial: Traditionally gathered, not bought (firewood, dung).

Ø  Renewable: Inexhaustible (solar, wind, hydro, biomass).

Ø  Non-renewable: Finite (coal, oil, gas).

Biofuels (Biodiesel & Bioethanol)

Biodiesel

Ø  Definition: Renewable fuel from vegetable oils/fats via transesterification.

Ø  Advantages: Renewable, eco-friendly, can use in existing diesel engines, reduces imports.

Ø  Production: Oil + alcohol + catalyst → biodiesel + glycerin (byproduct).

Ø  By-products: Glycerin (used in chemicals, animal feed), waste methanol (recycled), wastewater (treated).

Bioethanol

Ø  Definition: Alcohol fuel from fermentation of sugars, starch, or cellulose.

Ø  Raw Materials: Sugarcane, corn, molasses, cellulosic wastes.

Ø  Production: Hydrolysis (complex carbs → sugars) + fermentation (sugars → ethanol).

Solar Energy – Principles and Applications

Solar Radiation Basics

The sun is the ultimate energy source; solar energy is clean and inexhaustible.

Solar constant: ~1367 W/m² (amount of solar energy received per unit area at the top of Earth’s atmosphere).

Solar radiation at the Earth’s surface is less due to atmospheric absorption/scattering.

Solar Energy Devices

Ø  Solar Collectors: Devices to capture solar energy (flat-plate, evacuated tube).

Ø  Solar Water Heaters: Use solar collectors to heat water for domestic/industrial use.

Ø  Solar Cookers: Use mirrors/reflectors to concentrate sunlight for cooking.

Ø  Solar Dryers: Dry crops and food using solar heat.

Ø  Solar Photovoltaic (PV) Cells: Convert sunlight directly into electricity.

Wind Energy – Principles and Applications

Wind Energy Basics

Ø  Wind is caused by the uneven heating of the Earth’s surface.

Ø  Wind turbines convert kinetic energy of wind into mechanical or electrical energy.

Types of Wind Turbines

1.      Horizontal Axis Wind Turbine (HAWT): Most common, blades rotate around a horizontal axis.

2.      Vertical Axis Wind Turbine (VAWT): Blades rotate around a vertical axis.

Components of a Wind Turbine

Blades, rotor, shaft, gearbox, generator, tower, and control system.

Applications

Electricity generation (wind farms), water pumping (windmills), small-scale power for homes/farms.

Briquetting – MED – VED – Methods – Need & Benefits

What is Briquetting?

Briquetting is compressing loose biomass (agro/forest residues) into solid blocks (briquettes) for easier storage, transport, and use as fuel.

Suitable Materials

Sawdust, rice husk, groundnut shell, cotton stalks, bagasse, wood chips, coir pith, etc.

Ideal moisture: 10–15%; Ash content: <4%.

Densification Methods

Ø  Baling: Compresses biomass into bales.

Ø  Pelleting: Makes small pellets (0.3–1.3 cm diameter).

Ø  Cubing: Larger cylinders/cubes (2.5–5 cm).

Ø  Briquetting: Compacts into solid blocks.

Ø  Extrusion: Screw extruder forms logs (2.5–10 cm).

Types of Briquetting

1.      High Pressure: Piston press, Screw press (no binder needed, uses lignin).

2.  Medium Pressure + Heat: Sometimes with binder.

3.      Low Pressure + Binder: Uses external binding agents.

Combustion – Improved Chulha – Biomass Gas Stove

Combustion: Burning fuel with oxygen to release heat.

3T’s of Combustion: Temperature, Turbulence (mixing), Time.

Types of Combustion Devices

Ø  Conventional Chulha: Traditional mud stove, low efficiency (~10–15%).

Ø  Improved Chulha:

Ø  Single Pot: Double wall, preheats air, 24% efficiency.

Ø  Double Pot: Two cooking holes, 26% efficiency.

Ø  Community Chulha: Large, for group cooking, better air flow.

Ø  Biomass Gas Stove: Updraft gasifier, uses agro-waste, higher efficiency, cleaner burning.

Pyrolysis – Charcoal/Biochar Production

What is Pyrolysis?

Pyrolysis: Heating biomass (250–900°C) without oxygen to produce:

Ø  Biochar (solid)

Ø  Bio-oil (liquid)

Ø  Producer gas (gas)

Types of Pyrolysis

1.      Slow Pyrolysis (250–400°C): More biochar, less bio-oil.

2.  Intermediate Pyrolysis (350–450°C): Balanced products.

3.      Fast Pyrolysis (500–900°C): More bio-oil, less char.

Products & Uses

Ø  Biochar: Soil amendment, increases fertility, retains water/nutrients, reduces fertilizer needs.

Ø  Bio-oil: Substitute for fossil fuels in boilers, can be upgraded to transport fuels.

Ø  Producer Gas: Used for heating, power generation.

Gasification: Gasification is a thermo-chemical process that converts biomass into a combustible gas mixture (producer gas) using limited air/oxygen.

Main gases produced: CO (carbon monoxide), H₂ (hydrogen), CH₄ (methane), CO₂, N₂.

Gasifier Zones (Temperature Ranges)

Ø  Drying Zone (100–150°C): Removes moisture from biomass.

Ø  Pyrolysis Zone (150–700°C): Biomass breaks down into char, tars, and gases.

Ø  Oxidation Zone (700–1400°C): Char reacts with air, producing heat and gases.

Ø  Reduction Zone (800–1100°C): CO₂ and steam are reduced to CO and H₂.

Types of Gasifiers

1. Fixed Bed Gasifiers:

Ø  Updraft: Air enters from bottom, fuel from top. Gases exit from top. Handles high moisture/ash fuels. Gas has high tar content—good for heat, not engines.

Ø  Downdraft: Air and fuel move downward together. Gases exit from bottom. Gas has low tar content—suitable for engines and power generation.

Ø  Crossdraft: Air enters from the side. Used for coal, high gas velocity, less common for biomass.

2. Fluidized Bed Gasifiers: Used for large-scale applications.

Producer Gas Composition (Typical)

Ø  CO: 22%

Ø  H₂: 12%

Ø  CH₄: 2%

Ø  CO₂: 9%

Ø  N₂: 55%

Heating Value: ~1100–1200 kcal/m³

Factors Affecting Gasifier Performance

Fuel energy content, size/shape, moisture, ash, tar, air supply, temperature, reactor design.

Solar Energy – Solar Radiation, Solar Constant, Angles, Measurement

Solar energy: Electromagnetic energy from the sun.

Only a tiny fraction reaches Earth, but it’s still a massive, renewable resource.

Characteristics of Solar Radiation

Ø  Wavelengths: 0.2–4.0 micrometers.

Ø  Solar Constant: Amount of solar energy received outside Earth’s atmosphere = 1.353 kW/m².

Types of Solar Radiation

Ø  Ultraviolet (UV): <0.39 μm (~8%)

Ø  Visible: 0.39–0.78 μm (~46%)

Ø  Infrared (IR): >0.78 μm (~46%)

Solar Geometry – Important Angles

Ø  Latitude (Φ): North/South position on Earth.

Ø  Longitude: East/West position.

Ø  Declination (δ): Angle between equator and sun’s rays, changes with seasons (–23.5° to +23.5°).

Ø  Zenith Angle: Angle between sun’s rays and vertical.

Ø  Altitude Angle: Angle between sun’s rays and horizontal (complement of zenith).

Ø  Azimuth Angle (γ): Sun’s position east/west of south.

Ø  Slope (β): Tilt of a surface from horizontal.

Ø  Hour Angle (ω): Sun’s position east/west of local meridian (15° per hour).

Ø  Angle of Incidence: Between sun’s rays and surface normal.

Ø  Tilt Angle: Vertical angle between horizontal and array surface.

Ø  Measurement Instruments

Ø  Pyranometer: Measures global (total) solar radiation.

Ø  Pyrheliometer: Measures direct beam solar radiation.

Solar PV Systems – Principle & Applications

Principle

Photovoltaic effect: Solar cells (usually silicon) convert sunlight directly into electricity.

Components

Solar cell/module, battery, inverter, charge controller, loads.

Solar Dryers

Types

1. Natural Convection Dryer: Relies on natural airflow; simple, low cost, for small batches.

2. Forced Convection Dryer: Uses fans/blowers for airflow; faster, higher capacity, needs electricity.

3. Solar Tunnel Dryer: Semi-cylindrical, covered with UV-stabilized plastic; can be natural or forced convection.

Wind Mills – Types, Principles, Applications

1. Wind Formation

Caused by pressure differences, Coriolis force, and friction due to uneven heating of Earth.

2. Types of Winds

Ø  Primary: Trade winds, westerlies, polar winds.

Ø  Secondary: Monsoon, cyclones.

Ø  Tertiary: Local winds (land/sea breeze, mountain/valley breeze).

3. Wind Turbines

Ø  Horizontal Axis (HAWT): Most common, blades rotate parallel to ground.

Ø  Vertical Axis (VAWT): Blades rotate perpendicular to ground (Darrieus, Savonius).

4. Wind Energy Conversion System (WECS)

Ø  Converts wind energy into mechanical/electrical power.

Ø  Components: Rotor, gearbox, generator, tower.

Geothermal Energy

         Geothermal energy is the thermal energy generated and stored inside the Earth's crust.

Where it is applicable

Ø  Electricity Generation

Ø  Direct Heating Uses

Ø  Geothermal Heat Pumps (GHPs)

Ø  Industrial Applications

Advantages

Ø  Reliability

Ø  Renewable and Sustainable

Ø  Low Carbon Emissions

Ø  Minimal Land Use

Ø  Versatility

Ø  Energy Efficiency

Limitation

Ø  Location-specific

Ø  High upfront costs

Ø  Resource depletion risk

Ø  Limited scalability

Ø  Noise and visual impact

Types of Geothermal Resources

1. Hydrothermal fields: Water seeps down, heats up, returns as hot springs, geysers, etc.

2. Geo-pressurized (brine-methane) reservoirs: Deep, hot, high-pressure, salty water, sometimes with methane.

3. Petro-thermal (hot dry rock): Hot rocks without water; water is injected to extract heat.

4. Magma exploitation: Direct use of heat from molten rock (not yet commercial).

Wave Energy?

Energy from the movement of ocean waves (caused by wind and gravity).

How is it Captured?

Ø  Heaving Float: Float moves up/down with waves, drives a pump/generator.

Ø  Pitching Device: Hinged floats (like “nodding ducks”) convert wave motion to rotary movement.

Ø  Heaving & Pitching Float: Uses both up/down and tilting motion for energy conversion.

What is Tidal Energy?

Energy from the rise and fall of ocean tides (caused by moon/sun gravity).

How is it Captured?

Ø  Tidal Barrage: Dam across river estuary; water flows through turbines during tide changes.

Ø  Generation Types:

Ø  Ebb generation: Power as tide goes out.

Ø  Flood generation: Power as tide comes in.

Ø  Two-way generation: Both directions (less efficient).

Ocean Thermal Energy Conversion (OTEC)

What is OTEC?

Ø  Uses temperature difference between warm surface water and cold deep water to run a heat engine and generate electricity.

Ø  Needs at least 20°C temperature difference.

Types of OTEC Systems

1. Open Cycle: Warm seawater evaporates in low pressure, steam drives turbine, condenses with cold water.

2. Closed Cycle: Uses a fluid like ammonia; warm water vaporizes fluid, which drives turbine, then condenses with cold water.

3. Kalina Cycle: Uses ammonia-water mixture for higher efficiency.