Notes

1/30/13 GREEN HOUSE MANAGEMENT
Enzymes (catalyst for reaction)
Protein (chain of amino acids)
-As temperature lowers, reaction site can lower and slow reactions
-As temp hightens, reaction site can open more and destroy reaction site, or speed up reaction.

++HEAT REQUIREMENTS++
1BTU = 1pd. of h2o 1 degree F
Boiler horse power BHP= 1 BHU- 33475 BTU
*Heat lost..Movement of energy...
Convection- only at surface(ex. oven)
Conduction- Molecule to molecule
Radiation-Sun to earth (1 spot to another without heating inbetween)
Infiltration-Leakage into or out of greenhouse
Evaporation-Phase change (liquid to gas) 540 cal to 1 gram of water

WHERE DOES THIS HAPPEN?
1) through glazing via conduction
2) Heat lost from glazing surface by convection, if from some air, or water, movement past surface
3) Water evaporates from soil, surfaces in green house, and plants continuously. reduces temp by 5-10 degrees F
4) Energy gained or lost from green house via radiation. Sun warms greenhouse in daytime by radiation
5) Also lost by infiltration/exchange.
- Double layer PE, entire volume exchanged with outside temps 60 to 120 min.
- Glass greenhouse- 30 to 60 min
- Old glass green house- 15 to 30 min
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+++++Heating systems(see book) +++++
*4 types/ways*
TYPE 1) Central system
- All heat gen. in 1 place- Boiler
- Heat moved via pipes into or through greenhouse units
+ More efficient, but more money is needed to install but lasts longer.
- Uses either 180 degree F hot water or steam.
TYPE 2) Localized, or individualized system.-- Unit Systems
- Used for each "individual heaters" via furnace or heat generator
- costs 1/3 to 1/4 less than central system
++ 3 types
-A)Forced air, or unit heater used horizontally or vertically
-B) Salamander- Dumps fumes from burning into greenhouse (emergency)
-C) Low-energy, Infrared radiant heater. (may be 5 to 7 degrees cooler)
-good for Pacific Northwest
TYPE 3) Solar gain heating- couple types
TYPE 4) Geothermal heating- couple types
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HEAT DISTRIBUTION
++ After fuel is combusted/burned, heat must be distributed
(similar to loss of voltage as electricity is moved)
++ Make sure all parts of distribution systems are insulated
(2 SYSTEMS)
1) Water- Hot water or steam
Europe -95 degrees C
US- 85 degrees C
--Both US and Europe uses 102 degrees C and 11/4 to 11/2" piping
(pipes are considered low pressure)
General Rule: Put 1/3 of pipes overhead, and 2/3 on side walls or under benches. Why? heat rises, shading, and needs to keep plants warmer
----Special pipes with fins-- increses area that transmits heat
- 1' fin pipe= 8' of regular pipe( pg. 89) 1:4 or 1:12
-Need to know linear pipe amount.. "box coil" or trumboine coil"