This document outlines Eugene Odum's principles of energy ecology and their application to greenhouses and local food supply. It discusses using passive solar design and natural processes to efficiently capture and store energy for greenhouse use. Different greenhouse growth systems and materials are evaluated. Optimizing orientation, insulation, ventilation and thermal mass can reduce energy demands. Greenhouses combine human and natural ecologies to locally generate and save energy while enhancing food security in a carbon-neutral way.

1. Odum’s Energy Ecology
& Green Houses
Local and Ecological

2. Outline
 Odum Energy, Ecology  Heat Gain and Loss
and Economics  Energy Value
 Food Supply  Efficiency
 Greenhouses  Passive Solar Design
 Growth Systems  Orientation
 Ecology of  Recap: Importance of
Greenhouses Growing Local
 Energy in Greenhouses  Living Building
Examples

3. Odum’s Energy Ecology
 Growth Priming:
 Favors economic vitality
 Quality Vs. Quantity
 Reduction of subsidies
 Quality of Life
 From steady state periods
 Net Output Richer than
Input
 Solar Conversion
Necessary
 Simpler Agriculture as a
Primary Solution

4. Applied to Food Supply
 Food = Basis for Society
 Quality of Energy:
 Stability and Growth
 Vitality of Food
 Growth Materials
 Quality of Life:
 More Time with People
 Application of Purpose

5. Food Supply Considerations
 Human Population
 Estimated 9 billion in 2050 (6.6 billion in 2008)
 2/3 Expected to be Urban Dwellers
 Global Warming
 Influence
 Food supply
 Agriculture systems
 Arable land
 Influences Water Supply
 Needs to increase clean supply
 Needs to increase availability and distribution

6. A Look at Green Houses
 Human and Natural Ecology Combined
 Local Energy Capture and Storage
 Input Energy Stored for Output Energy Use
 Local Energy Generation and Savings
 Uses Natural Processes and Natural Storage/Blocking
 Carbon and GHG Neutrality: Possible!
 Community Based Designed
 Based on need, and available resources
 Enhance Food Security
 Adaptable
 Efficient
 Automation possible

7. Types of Growth Systems
 Mono Culture
 Polyculture
 Biodynamic
 Hydroponics
 Aquaculture
 Algae for Energy
Growth

8. Ecology of Green Houses
 Incorporate with Waste Streams or Algae
Culture for Nutrient Enhancement
 Create ‘Green Space’ in Office Space
 Reduce Building Energy Needs
 Reduce Footprint of Greenhouses and Food
Supply
 Reduce Nutrient Runoff
 Through Monitoring

9. Energy in Greenhouses
 Energy from our environments
 Continuous and Renewed
 Solar, Organic, Natural Gas*, Water, Wind, Wood
 Stored
 Coal and Fossil Fuels, Natural Gas*, Nuclear
 In Ecology:
 Where continuous energy creates/generates stored energy
 Smart energy use is the lower energy ‘cost’ to produce the
same stored energy and/or energy output
 70-80% Used for Heating; 10-15% for Electricity [2]

10. Heat Gain & Loss
 Conduction
 Heat conducted through materials
 U-value – Btu/(hr-ºF-sq.ft.)
 Convection
 Heat exchange between moving
fluid (air) and solid surfaces
 Radiation
 Heat transfer between two bodies
without direct contact or transport
medium
 Sunlight
 Air Leakage/Infiltration
 Exchange of interior and exterior air
through small leaks and holes.

11. Increasing Energy Value
 Growth Versus and Towards Stability
 Reduce inefficiency of energy growth process
 Reduce Dependence on Fuel subsidies
 Reduce Use of Non-Renewals
 Reduce Pollution
 Increase Output Recycling
 Increase Efficiency of Current Systems
 Reduce outputs for maintenance and general operation.

12. Enhancing Efficiency
 Stand alone
 Isolated growing conditions
 Include lots of plants to heat
 Natural ventilation
 Opening Side Walls or Top Windows
 1.7-1.8 – heat loss area to floor area (3000sq. ft.)
 Materials selection
 Water Collection/ Indoor Storage
 Color Selection
 Orientation

13. Passive Solar Design
[3]

14. Passive Solar Design (con’t)

15. Greenhouse: Passive Solar Design
Thermal Mass
(BTU/sqft/Fo)
Brick 24
Concrete 35
Earth 20
Sand 22
Steel 59
Stone 35
Water 63
Wood 10.6
Attached greenhouse:
2.5 gallons per sq. ft. of south facing glazing area for cool climates (4 month winters)
2 gallons per sq. ft. of south facing glazing area for temperate climates (3 month winters)
1 gallon per sq. ft. of south facing glazing area for warmer climates (2 month winters)
Free standing greenhouse:
3 gallons per sq. ft. of south facing glazing area for cool climates (4 month winters)
2.5 gallons per sq. ft. of south facing glazing for temperate climates (3 month winters)
2 gallon per sq. ft. of south facing glazing for warmer climates (2 month winters)

16. Sample R and U Values
Polycarbonate 6mm quad wall R = 1.79
Polycarbonate 8mm quad wall R = 2.13
Polycarbonate 16mm triple wall R = 2.5
Polycarbonate 8mm triple wall R = 2.0-2.1
Polycarbonate 8mm double wall R = 1.6
Acrylic double wall R = 1.82
Glass double layer R = 1.5 – 2.0
Glass double layer low-e R = 2.5
Glass triple layer 1 / 4 “ ( 0.6 cm) air space R = 2.13
Fiberglass glazing- single layer R = .83
Polyethylene Double 5mil film R = 1.5
Polyethylene Double 6mil film R = 1.7
Polyethylene single film R = 0.87
6 inches (15 cm) of fiberglass bat insulation R = 19.0
Polystyrene (styrofoam) 1 inch (2.5 cm) thick R = 4.0

17. Orientation
 East/West to Maximize Winter Sunlight
 Incorporate Cooling Sections for Air Flow
 Moveable Gutter Overhangs
[6] [3]

18. Increase Energy Value of Food
 Grown in biodynamic, or polyculture systems
 Grow and Buy Organic
 Process By Hand
 Picked When Ripe Food
 Eat Fresh
 Soil Enhancement

19. External Greenhouse Example:
Vertical Wall Green House
 Increased Food Supply
 Hydroponics
 Double-Skin Facades
 Reduce Maintenance
 Provide Shade
 Air Treatment
 Evaporative
Cooling
 Reduced Costs
 Mitigation
 Insulation

20. BioMachine: Buildings of Future
 Incorporate Automated Systems
 Clean Air
 Enhance Nutrients
 Irrigation Supply and Water Management
 Local Harvesting
 Solar Panels
 Solar Thermal
 Passive Heating and Cooling

21. Conclusions
 Human Ecological Incorporation
 Total Waste and Energy Stream
Considerations
 Reduced Need for Energy
 Increase Food Supply and Security
 Adaptability and Self Design

22. References
[1] - HT Odum- Energy Ecology and Economics
[2] Sanford, Scott; Energy Conservation for Greenhouses;
http://www.uwex.edu/energy/pubs/GreenhouseEC_SAREApril2010.pdf
[3] Sethi, V.P.; Survey and evaluation of heating technologies for worldwide agriculture
greenhouse applications; 2010
[4] Sethi, V.P. ; Experimental and economic study of a greenhouse thermal control system using
aquifer water; 2007
[5] Theodore Caplow; Vertically Integrated Greenhouse: Realizing the Ecological Benefits of
Urban Food Production; Ecocity World Summit 2008 Proceedings; 2008
[6] David Roper; Solar Greenhouses; http://www.roperld.com/science/solargreenhouses.htm