2. All greenhouses collect solar energy. Solar greenhouses are designed not only to collect solar energy during sunny
days but also to store heat for use at night or during periods when it is cloudy. They can either stand alone or be
attached to houses or barns. A solar greenhouse may be an underground pit, a shed-type structure, or a hoophouse.
Large-scale producers use free-standing solar greenhouses, while attached structures are primarily used by home-
scale growers.
Passive solar greenhouses are often good choices for small growers because they are a cost-efficient way for farmers
to extend the growing season. In colder climates or in areas with long periods of cloudy weather, solar heating may
need to be supplemented with a gas or electric heating system to protect plants against extreme cold. Active solar
greenhouses use supplemental energy to move solar heated air or water from storage or collection areas to other
regions of the greenhouse. Use of solar electric (photovoltaic) heating systems for greenhouses is not cost-effective
unless you are producing high-value crops.
Hazards due to increased weather turbulence:
Hail
Tornados
High straight-line winds
Build-up of snow, ice
The majority of the books and articles about old-style solar greenhouses were published in the 1970s and 1980s.
Since then, much of this material has gone out of print, and some of the publishers are no longer in business. While
contact information for companies and organizations listed in these publications is probably out of date, some of the
technical information contained in them is still relevant.
The newest form of solar greenhouse, widely adopted by U.S. producers, is high tunnels. The term glazing, as used
in this publication, includes reference to polyethylene coverings for hoop houses.
Out-of-print publications often can be found in used bookstores, libraries, and through the inter-library loan program.
Some publications are also available on the Internet. Bibliofind is an excellent, searchable Web site where many used
and out-of-print books can be located.
As you plan to construct or remodel a solar greenhouse, do not limit your research to books and articles that
specifically discuss "solar greenhouses." Since all greenhouses collect solar energy and need to moderate
temperature fluctuations for optimal plant growth, much of the information on "standard" greenhouse management
is just as relevant to solar greenhouses. Likewise, much information on passive solar heating for homes is also
pertinent to passive solar heating for greenhouses. As you look through books and articles on general greenhouse
design and construction, you will find information relevant to solar greenhouses in chapters or under topic headings
that discuss:
energy conservation
glazing materials
3. floor heating systems
insulation materials
ventilation methods
In books or articles on passive solar heating in homes or other buildings, you can find useful information on solar
greenhouses by looking for chapters or topic headings that examine:
solar orientation
heat absorption materials
heat exchange through "phase-change" or "latent heat storage materials"
This updated resource list includes listings of books, articles, and Web sites that focus specifically on solar
greenhouses, as well as on the topics listed above.
Related ATTRA Publications
Season Extension Techniques for Market Gardeners
Organic Greenhouse Vegetable Production
Greenhouse and Hydroponic Vegetable Production Resources on the Internet
Potting Mixes for Certified Organic Production
Integrated Pest Management for Greenhouse Crops
Herbs: Organic Greenhouse Production
Plug and Transplant Production for Organic Systems
Compost Heated Greenhouses
Root Zone Heating for Greenhouse Crops
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Basic Principles of Solar Greenhouse Design
Solar greenhouses differ from conventional greenhouses in the following four ways.(1) Solar greenhouses:
have glazing oriented to receive maximum solar heat during the winter.
use heat storing materials to retain solar heat.
have large amounts of insulation where there is little or no direct sunlight.
use glazing material and glazing installation methods that minimize heat loss.
rely primarily on natural ventilation for summer cooling.
Understanding these basic principles of solar greenhouse design will assist you in designing, constructing, and
maintaining an energy-efficient structure. You can also use these concepts to help you search for additional
information, either on the "Web," within journals, or in books at bookstores and libraries.
4. Back to top
Solar Greenhouse Designs
Attached solar greenhouses are lean-to structures that form a room jutting out from a house or barn. These
structures provide space for transplants, herbs, or limited quantities of food plants. These structures typically have a
passive solar design.
Freestanding solar greenhouses are large enough for the commercial production of ornamentals, vegetables, or
herbs. There are two primary designs for freestanding solar greenhouses: the shed type and the hoophouse. A shed-
type solar greenhouse is oriented to have its long axis running from east to west. The south-facing wall is glazed to
collect the optimum amount of solar energy, while the north-facing wall is well-insulated to prevent heat loss. This
orientation is in contrast to that of a conventional greenhouse, which has its roof running north-south to allow for
uniform light distribution on all sides of the plants. To reduce the effects of poor light distribution in an east-west
oriented greenhouse, the north wall is covered or painted with reflective material.(2)
Freestanding shed-type solar greenhouses(2)
For cold winters, northern latitudes, and year-round use:
• steep north roof pitched to the highest summer sun angle for maximum year-round light
reflection onto plants;
• vertical north wall for stashing heat storage.
• 40-60° sloped south roof glazing.
• vertical kneewall high enough to accommodate planting beds and snow sliding off roof.
• end walls partially glazed for added light.
• The Brace Institute design continues the north roof slope down to the ground (eliminating
the north wall), allowing for more planting area in ground, but no heat storage against the
north wall.
For cold winters, middle U.S. latitudes, and year-round use (similar to the design
popularized by Domestic Technology Institute, see Resources for plans and address):
• 45-60° north roof slope.
• vertical north wall for stacking heat storage.
• 45° south roof glazing.
• vertical kneewall.
• part of end walls glazed for additional light.
5. For milder winters, southern U.S. latitudes, and year-round use where less heat storage is
needed:
• 45-70° north roof slope—roof slope steeper and north wall shorter if less space is needed
for stacking heat storage.
• roof can extend down to ground, eliminating back kneewall if no storage is use.
• 20-40° south roof glazing.
• front kneewall as high as is needed for access to beds in front.
• most of end walls glazed for additional light.
Freestanding hoophouses are rounded, symmetrical structures. Unlike the shed-type solar greenhouses, these do not
have an insulated north side. Solarization of these structures involves practices that enhance the absorption and
distribution of the solar heat entering them. This typically involves the collection of solar heat in the soil beneath the
floor, in a process called earth thermal storage (ETS), as well as in other storage materials such as water or rocks.
Insulation of the greenhouse wall is important for minimizing heat loss. Heat absorption systems and insulation
methods are discussed in detail in the following sections.
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Solar Heat Absorption
The two most critical factors affecting the amount of solar heat a greenhouse is able to absorb are:
The position or location of the greenhouse in relation to the sun
The type of glazing material used
Solar Orientation
Since the sun's energy is strongest on the southern side of a building, glazing for solar greenhouses should ideally
face true south. However, if trees, mountains, or other buildings block the path of the sun when the greenhouse is in
a true south orientation, an orientation within 15° to 20° of true south will provide about 90% of the solar capture of
a true south orientation. The latitude of your location and the location of potential obstructions may also require that
you adjust the orientation of your greenhouse slightly from true south to obtain optimal solar energy gain.(2) Some
growers recommend orienting the greenhouse somewhat to the southeast to get the best solar gain in the spring,
especially if the greenhouse is used primarily to grow transplants.(3) To determine the proper orientation for solar
buildings in your area, visit the sun chart program at the University of Oregon Solar Radiation Monitoring Laboratory
Web page. You need to know your latitude, longitude, and time zone to use this program.
6. Solar path at 40° north latitude (2)
Slope of Glazing Material
In addition to north-south orientation, greenhouse glazing should be properly sloped to absorb the greatest amount
of the sun's heat. A good rule of thumb is to add 10° or 15° to the site latitude to get the proper angle. For example,
if you are in northern California or central Illinois at latitude 40° north, the glazing should be sloped at a 50° to 55°
angle (40° + 10° or 15°).(4)
Glazing
Glazing materials used in solar greenhouses should allow the greatest amount of solar energy to enter into the
greenhouse while minimizing energy loss. In addition, good plant growth requires that glazing materials allow a
natural spectrum of photosynthetically active radiation (PAR) to enter. Rough-surface glass, double-layer rigid plastic,
and fiberglass diffuse light, while clear glass transmits direct light. Although plants grow well with both direct and
diffuse light, direct light through glazing subdivided by structural supports causes more shadows and uneven plant
growth. Diffuse light passing through glazing evens out the shadows caused by structural supports, resulting in more
even plant growth.(5, 6)
Many new greenhouse glazing materials have emerged in recent decades. Plastics now are the dominant type of
glazing used in greenhouses, with the weatherability of these materials being enhanced by ultraviolet radiation
degradation inhibitors, infrared radiation (IR) absorbency, anti-condensation drip surfaces, and unique radiation
transmission properties.(7)
The method used for mounting the glazing material affects the amount of heat loss.(8) For example, cracks or holes
caused by the mounting will allow heat to escape, while differences in the width of the air space between the two
glazes will affect heat retention. Installation and framing for some glazing materials, such as acrylics, need to
7. account for their expansion and contraction with hot and cold weather.(7) As a general rule, a solar greenhouse
should have approximately 0.75 to 1.5 square feet of glazing for each square foot of floor space.(1)
Table 1. Glazing Characteristics
Glass—single layer Factory sealed double glass
Light transmission*: 85-90% Light transmission*: 70-75%
R-value**: 0.9 R-value**: double layer 1.5-2.0, low-e 2.5
Advantages: Advantages:
• Lifespan indefinite if not broken • Lifespan indefinite if not broken
• Tempered glass is stronger and requires • Can be used in areas with freezing
fewer support bars temperatures
Disadvantages: Disadvantages:
• Fragile, easily broken • Heavy
• May not withstand weight of snow • Clear glass does not diffuse light
• Requires numerous supports • Difficult to install, requires precise framing
• Clear glass does not diffuse light
Polyethylene—single layer Polyethylene—double layer
Light transmission*: 80-90% - new material Light transmission*: 60-80%
R-value**: single film 0.87 R-value** double films: 5ml film 1.5, 6ml film
1.7
Advantages:
• IR films have treatment to reduce heat loss Advantages:
• No-drop films are treated to resist • Heat loss significantly reduced when a blower
condensation is used to provide an air space between the two
• Treatment with ethyl vinyl acetate results in layers
resistance to cracking in the cold and tearing • IR films have treatment to reduce heat loss
• Easy to install, precise framing not required • No-drop films are treated to resist
• Lowest cost glazing material condensation
• Treatment with ethyl vinyl acetate results in
Disadvantages: resistance to cracking in the cold to tearing
• Easily torn • Easy to install, precise framing not required
• Cannot see through • Lowest-cost glazing material
• UV-resistant polyethylene lasts only 1-2
years Disadvantages:
• Light transmission decreases over time • Easily torn
• Expand and sag in warm weather, then shrink • Cannot see through
in cold weather • UV-resistant polyethylene lasts only 1-2 years
• Light transmission decreases over time
• Expand and sag in warm weather, then shrink
in cold weather
8. Polyethylene—corrugated high density Laminated Acrylic/Polyester film—double
Light transmission*: 70-75% layer
R-value**: 2.5-3.0 Light transmission*: 87%
R-value**: 180%
Advantages:
• Mildew, chemical, and water resistant Advantages:
• Does not yellow • Combines weatherability of acrylic with high
service temperature of polyester
Disadvantages: • Can last 10 years or more
n/a
Disadvantages:
• Arcrylic glazings expand and contract
considerably; framing needs to allow for this
change in size
• Not fire-resistant
Impact modified acrylic—double layer Fiber reinforced plastic (FRP)
Light transmission*: 85% Light transmission*: 85-90% - new material
R-value**: single layer 0.83
Advantages:
• Not degraded or discolored by UV light Advantages:
• High impact strength, good for locations with • The translucent nature of this material diffuses
hail and distributes light evenly
• Tedlar-treated panels are resistant to weather,
Disadvantages: sunlight, and acids
• Arcrylic glazings expand and contract • Can last 5 to 20 years
considerably; framing needs to allow for this
change in size Disadvantages:
• Not fire resistant • Light transmission decreases over time
• Poor weather-resistance
• Most flammable of the rigid glazing materials
• Insulation ability does not cause snow to melt
Polycarbonate—double wall rigid plastic Polycarbonate film—triple and quad wall
Light transmission*: 83% rigid plastic
R-value**: 6mm 1.6, 8mm 1.7 Light transmission*: 75%
R-value** triple walls: 8mm 2.0-2.1, 16mm 2.5
Advantages: R-value** quad wall: 6mm 1.8, 8 mm 2.1
• Most fire-resistant of plastic glazing
materials Advantages:
• UV-resistant • Most fire-resistant of plastic glazing materials
• Very strong • UV-resistant
• Lightweight • Very strong
• Easy to cut and install • Lightweight
• Provides good performance for 7-10 years • Easy to cut and install
9. • Provides good performance for 7-10 years
Disadvantages:
• Can be expensive Disadvantages:
• Not clear, translucent • Can be expensive
• Not clear, translucent
Sources: (2, 6, 7, 13, 14)
* note that framing decreases the amount of light that can pass through and be available as solar
energy
** R-Value is a common measure of insulation (hr°Fsq.ft/BTU)
You need to understand four numbers when selecting glazing for solar greenhouses. Two numbers describe the heat efficiency of
the glazing, and the other two numbers are important for productive plant growth. Many glazing materials include a National
Fenestration Rating Council sticker that lists the following factors:
• The SHGC or solar heat gain coefficient is a measure of the amount of sunlight that passes through a glazing material. A
number of 0.60 or higher is desired.
• The U-factor is a measure of heat that is lost to the outside through a glazing material. A number of 0.35 BTU/hr-ft2-F or less is
desired.
• VT or visible transmittance refers to the amount of visible light that enters through a glazing material. A number of 0.70 or
greater is desired.
• PAR or photosynthetically active radiation is the amount of sunlight in the wavelengths critical for photosynthesis and healthy
plant growth. PAR wavelength range is 400-700 nanometers (a measure of wavelength).
Note: When choosing glazing, look at the total visual transmittance, not PAR transmittance, to see whether the material allows
the spectrum of light necessary for healthy plant growth.
In addition to energy efficiency and light transmission, you should consider the following when choosing glazing materials for
your greenhouse:
• Lifespan
• Resistance to damage from hail and rocks
• Ability to support snowload
• Resistance to condensation
• Sheet size and distance required between supports
• Fire-resistance
• Ease of installation
(Based on 6, 9, 10, 11, 12, 13, 14)
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Solar Heat Storage
For solar greenhouses to remain warm during cool nights or on cloudy days, solar heat that enters on sunny days
must be stored within the greenhouse for later use. The most common method for storing solar energy is to place
rocks, concrete, or water in direct line with the sunlight to absorb its heat.(1)
10. Brick or concrete-filled cinder block walls at the back (north side) of the greenhouse can also provide heat storage.
However, only the outer four inches of thickness of this storage material effectively absorbs heat. Medium to dark-
colored ceramic tile flooring can also provide some heat storage.(15) Walls not used for heat absorption should be
light colored or reflective to direct heat and light back into the greenhouse and to provide a more even distribution of
light for the plants.
Storage Materials
The amount of heat storage material required depends on your location. If you live in southern or mid-latitude
locations, you will need at least 2 gallons of water or 80 pounds of rocks to store the heat transmitted through each
square foot of glazing.(16) If you live in the northern states, you will need 5 gallons or more of water to absorb the
heat that enters through each square foot of glazing.(1) Approximately three square feet of four-inch thick brick or
cinder block wall is required for each square foot of south-facing glass.(15)
The amount of heat-storage material required also depends on whether you intend to use your solar greenhouse for
extending the growing season, or whether you want to grow plants in it year-round. For season extension in cold
climates, you will need 2 ½ gallons of water per square foot of glazing, or about half of what you would need for
year-round production.(2)
If you use water as heat-storage material, ordinary 55-gallon drums painted a dark, non-reflective color work well.
Smaller containers, such as milk jugs or glass bottles, are more effective than 55-gallon drums in providing heat
storage in areas that are frequently cloudy. The smaller container has a higher ratio of surface area, resulting in
more rapid absorption of heat when the sun does shine.(14) Unfortunately, plastic containers degrade after two or
three years in direct sunlight. Clear glass containers provide the advantages of capturing heat better than dark metal
containers and not degrading, but they can be easily broken.(17)
Trombe walls are an innovative method for heat absorption and storage. These are low walls placed inside the
greenhouse near the south-facing windows. They absorb heat on the front (south-facing) side of the wall and then
radiate this heat into the greenhouse through the back (north-facing) side of the wall. A Trombe wall consists of an
8- to 16-inch thick masonry wall coated with a dark, heat-absorbing material and faced with a single or double layer
of glass placed from 3/4" to 6" away from the masonry wall to create a small airspace. Solar heat passes through the
glass and is absorbed by the dark surface. This heat is stored in the wall, where it is conducted slowly inward
through the masonry. If you apply a sheet of metal foil or other reflective surface to the outer face of the wall, you
can increase solar heat absorption by 30-60% (depending on your climate) while decreasing the potential for heat
loss through outward radiation.(10, 18)
11. Trombe wall.
Photo: Australian Center for Renewable Energy
Water walls are a variation of the Trombe wall. Instead of a masonry wall, water-filled containers are placed in line
with the sun's rays between the glazing and the greenhouse working space. The water can be in hard, plastic tubes
or other sturdy containers, and the top of the wall can serve as a bench. The Solviva solar greenhouse water wall
consists of two 2x4 stud walls, with the studs placed two feet on center. A one-foot spacer connects the two walls.
Plastic-covered horse fence wire was then fastened to each stud wall, and heavy-duty, dark-colored plastic water
bags were inserted into the space between the two walls. The stud walls were positioned vertically in line with the
sun's rays prior to the bags being filled with water.(19) Both the Solviva and Three Sisters Farm Web pages provide
designs for constructing solar greenhouses using water walls.
You can use rocks instead of water for heat storage. The rocks should be ½ to 1½ inches in diameter to provide
high surface area for heat absorption.(5) They can be piled in wire-mesh cages to keep them contained. Since rocks
have a much lower BTU storage value than water (35 BTU/sq.ft/°F for rocks versus 63 for water) (13), you will need
three times the volume of rocks to provide the same amount of heat storage. Rocks also have more resistance to air
flow than water, resulting in less efficient heat transfer.(20)
Whichever material you choose to use for heat storage, it should be placed where it will collect and absorb the most
heat, while losing the least heat to the surrounding air. Do not place the thermal mass so that it touches any exterior
walls or glazing, since this will quickly draw the heat away.
Phase-change
Instead of water or rocks for heat storage, you can use phase-change materials. While phase-change materials are
usually more expensive than conventional materials, they are 5 to 14 times more effective at storing heat than water
or rocks. Thus, they are useful when space is limited. Phase-change materials include:
disodium phosphate dodecahydrate
sodium thiosulfate pentahydrate
paraffin
Glauber's salt (sodium sulphate dcahydrate)
calcium chloride hexahydrate and
12. fatty acids (21, 22)
They absorb and store heat when they change from solid to liquid phase, and then release this heat when they
change back into a solid phase.(5) Calcium chloride hexahydrate has a heat storing capacity 10 times that of
water.(23) These materials are usually contained in sealed tubes, with several tubes required to provide sufficient
heat storage. Because of the ability of phase-change materials to absorb high quantities of heat, they also are useful
in moderating greenhouse temperatures in the summer.
Most of the research on the use of phase-change materials for greenhouses has been conducted in Europe, Israel,
Japan, and Australia. In Israel, phase-change materials were incorporated into greenhouse glazing, which increased
heat capture and retention, but reduced the transparency of the glazing on cloudy days when the phase change
material did not become liquid.(24) At the time of publication, two companies were identified—one in the U.S. and
another in Australia—that sell underfloor heating systems using phase-change materials.(25, 26) Phase-change
drywall, currently under research, incorporates phase-change materials inside common wallboard to increase its heat
storage capacity and could replace heavier, more expensive, conventional thermal masses used in passive-solar
space heating.(27) See the reference section for a listing of publications and Web sites that provide additional
information about phase change materials.
For more information, see the Phase Change Thermal Energy Storage Web site provides a detailed discussion of this
technology.
For many homeowners, building an attached solar greenhouse is very appealing. They believe that they can extend their garden's
growing season while reducing their home heating bills. Unfortunately, there is a contradiction between the use of a greenhouse
to grow plants and the use of it as a solar collector for heating the house.(9, 28)
• To provide heat for a home, a solar collector needs to be able to collect heat in excess of what plants can tolerate.
• Much of the heat that enters into a greenhouse is used for evaporating water from the soil and from plant leaves, resulting in
little storage of heat for home use.
• A home heat collector should be sealed to minimize the amount of heat loss. Greenhouses, however, require some ventilation to
maintain adequate levels of carbon dioxide for plant respiration and to prevent moisture build-up that favors plant diseases.
Bioshelters provide an exception to this rule. In bioshelters, the food-producing greenhouse is not an "add-on" to the house but is
an integral part of the living space. Bioshelters often integrate fish or small animals with vegetable production to complete
nutrient cycles. Biological control measures and plant diversity are used to manage pests in a way that is safe for people and pets
in the living quarters. First pioneered by The New Alchemy Institute of East Falmouth, Massachusetts, in the 1970s, Solviva and
the Three Sisters Farm carry on the bioshelter tradition.
Active Solar
An active method for solar heating greenhouses uses subterranean heating or earth thermal storage solar heating. This
method involves forcing solar-heated air, water, or phase-change materials through pipes buried in the floor. If you
use hot air for subsurface heating, inexpensive flexible drainage or sewage piping about 10 centimeters (4 inches) in
diameter can be used for the piping. Although more expensive, corrugated drainage tubing provides more effective
heating than smooth tubing, since it allows for greater interaction between the heat in the tube and the ground. The
surface area of the piping should be equal to the surface area of the floor of the greenhouse. You can roughly
13. calculate the number of feet of four-inch tubing you will need by dividing the square feet of greenhouse floor area by
two. Once installed, these pipes should be covered with a porous flooring material that allows for water to enter into
the soil around them, since moist soil conducts heat more effectively than dry soil. The system works by drawing hot
air collected in the peak of the roof down through pipes and into the buried tubing. The hot air in the tubes warms
the soil during the day. At night, cool air from the greenhouse is pumped through the same tubing, causing the warm
soil to heat this air, which then heats the greenhouse.(29, 30) For more information on this design, see Solar
Greenhouses for Commercial Growers (29), or visit the Web page of Going Concerns Unlimited, a solar energy
company in Colorado.
Root-zone thermal heating with water is normally used in conjunction with gas-fired water heaters. This system can
be readily adapted to solar and works well with both floor or bench heat. Bench-top heating with root-zone thermal
tubing is widely practiced in modern greenhouse production and can be installed easily. A permanent floor heating
system consists of a series of parallel PVC pipes embedded on 12" to 16" centers in porous concrete, gravel, or sand.
Water is heated in an external solar water heater then pumped into the greenhouse and circulated through the pipes,
warming the greenhouse floor. Containerized plants sitting directly on the greenhouse floor receive root-zone heat.
Additional information on root zone heating can be found in the ATTRA publication Root Zone Heating for Greenhouse
Crops.
The Solviva greenhouse uses a variation of active solar heating. The system in this greenhouse relies on heat
absorption by a coil of black polybutylene pipe set inside the peak of the greenhouse. The pipe coil lays on a black
background and is exposed to the sun through the glazing. A pump moves water from a water tank, located on the
floor of the greenhouse, to the coiled pipe, and back to the tank. Water heated within the coils is capable of heating
the water in the tank from 55°F to 100°F on a sunny day. The heat contained in the water tank helps keep the
greenhouse warm at night.(19)
Greenhouse management practices also can affect heat storage. For example, a full greenhouse stores heat
better than an empty one. However, almost half of the solar energy is used to evaporate water from leaf and soil
surfaces and cannot be stored for future use.(5, 31) Solar heat can be complemented with heat from compost as
described in the ATTRA publication Compost Heated Greenhouses. Besides adding some heat to the greenhouse,
increased carbon dioxide in the greenhouse atmosphere, coming from the decomposition activities of the
microorganisms in the compost, can increase the efficiency of plant production.
While solar greenhouses can extend your growing season by providing relatively warm conditions, you should carefully select
the types of plants that you intend to grow, unless you are willing to provide backup heating and lighting.
Vegetables and herbs that are suitable for production in a winter solar greenhouse include:
Cool temperature tolerant: Basil, celery, dill, fennel, kale, leaf lettuce, marjoram, mustard greens, oregano, parsley, spinach,
Swiss chard, turnips, cabbage, collards, garlic, green onions, and leeks.
Require warmer temperatures: Cherry tomatoes, large tomatoes, cucumbers (European type), broccoli, edible pod peas,
eggplant, and peppers.
(Based on 28)
14. Back to top
Insulation
Wall and Floor Insulation
Good insulation helps to retain the solar energy absorbed by thermal mass materials. Keeping heat in requires you to
insulate all areas of the greenhouse that are not glazed or used for heat absorption. Seal doors and vents with
weather stripping. Install glazing snugly within casements. Polyurethane foams, polystyrene foams, and fiberglass
batts are all good insulating materials. But these materials need to be kept dry to function effectively. A vapor barrier
of heavy-duty polyethylene film placed between the greenhouse walls and the insulation will keep your greenhouse
well insulated.(1) Unglazed areas should be insulated to specifications of your region. For example, R-19 insulation is
specified for greenhouses in Illinois (1) and in Missouri (24), while R-21 is recommended for walls in New
Mexico.(10) The ZIP-Code Insulation Program Web site provides a free calculator for finding recommended insulation
R-values for houses based on your zip code.
Richard Nelson of SOLAROOF developed an innovative way to insulate greenhouse walls in a hoophouse-style
greenhouse. This system involves constructing a greenhouse with a double layer of plastic sheeting as glazing.
Bubble machines (such as are used to create bubbles at parties) are installed in the peak of the greenhouse between
the two layers of plastic. At least two generators should be installed, at either end of the greenhouse. During the
winter, the bubble machines face north and blow bubbles into space between two sheets of plastic on the north side
of the greenhouse to provide R-20 or higher insulation for northern winters. During the summer, the bubble
machines can be turned to face south to provide shading against high heat.(33)
15. Bubble greenhouse design.
On greenhouse floors, brick, masonry, or flagstone serves as a good heat sink. However, they can quickly lose heat
to the ground if there is not an insulating barrier between the flooring and the soil. To protect against heat loss,
insulate footings and the foundation with 1- to 2-inch sheets of rigid insulation or with a 4-inch-wide trench filled with
pumice stone that extends to the bottom of the footings. You also can insulate flooring with four inches of pumice
rock. Besides insulating the floor, this method also allows water to drain through. (16)
External Insulation
You also can insulate your greenhouse by burying part of the base in the ground or building it into the side of a
south-facing hill.(5) Straw bales or similar insulating material also can be placed along the unglazed outside walls to
reduce heat loss from the greenhouse.(34) Underground or bermed greenhouses provide excellent insulation against
both cold winter weather and the heat of summer. They also provide good protection against windy conditions.(35)
Potential problems with an underground greenhouse are wet conditions from the water table seeping through the soil
on the floor and the entry of surface water through gaps in the walls at the ground level. To minimize the risk of
water rising through the floor, build the underground greenhouse in an area where the bottom is at least five feet
above the water table. To prevent water from entering the greenhouse from the outside, dig drainage ditches around
the greenhouse to direct water away from the walls. Also, seal the walls with waterproof material such as plastic or a
fine clay. An excellent description of how to build a simple pit greenhouse is provided at the Web page for the
Benson Institute, a division of the College of Biology and Agriculture at Brigham Young University (BYU). This
Institute has a campus in Bolivia where students built an underground greenhouse based on local, traditional
practices.(36)
16. The Walipini greenhouse, a traditional underground greenhouse
from Bolivia.(36)
Glazing is what allows light and heat into a solar greenhouse. It can also be the greatest area for heat loss. As
mentioned previously, increasing the insulating value of glazing often decreases the amount of sunlight entering the
greenhouse. When selecting glazing for your greenhouse, look for materials that provide both good light transmission
and insulating value. For example, polyethylene films referred to as "IR films" or "thermal films" have an additive that
helps reduce heat loss.(37) Double or triple glazing provides better insulation than single glazing. Some greenhouse
growers apply an extra layer of glazing—usually a type of film—to the interior of their greenhouses in winter to
provide an extra degree of insulation. Adding a single or double layer of polyethylene film over a glass house can
reduce heat loss by as much as 50%.(38) By using two layers of polyethylene film in plastic-film greenhouses with a
small fan blowing air between them to provide an insulating air layer, heat losses can be reduced by 40% or more,
as compared to a single layer of plastic.(39)
Greenhouse curtains limit the amount of heat lost through greenhouse glazing during the night and on cloudy
days. By installing greenhouse insulation sheets made from two-inch thick bats of polystyrene, you can reduce by
almost 90% the heat that would otherwise be lost through the glazing. For a small greenhouse where labor is not a
large constraint, you can manually install the polystyrene sheets at night and remove them in the morning. Magnetic
clips or Velcro fasteners will facilitate the installation.(1) Alternatively, you can install thermal blankets made of
polyethylene film, foam-backed fiberglass, or foil-faced polyethylene bubble material. These blankets are supported
on wire tracks and can be raised or lowered using pulleys. While greenhouse curtains composed of thermal blankets
are usually opened and closed manually, a few manufactures have motorized roll-up systems that store the blanket
near the greenhouse peak.(5)
17. Solar greenhouse with solar curtains, water wall, and water heat storage
on the north wall.(2)
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Ventilation
A building designed to collect heat when temperatures are cold also needs to be able to vent heat when
temperatures are warm. Air exchange also is critical in providing plants with adequate levels of carbon dioxide and
controlling humidity. Because of the concentrated air use by plants, greenhouses require approximately two air
exchanges per minute (in contrast to the one-half air exchange per minute recommended for homes). To determine
the flow requirements for your greenhouse, multiply the volume of the greenhouse by two to get cubic feet of air
exchange per minute, which is the rate used in determining the capacity of commercial evaporative coolers.
Roof-ridge and sidewall vents provide natural ventilation. The sidewall vents allow cool air to flow into the sides of
the greenhouse, while ridge vents allow the rising hot air to escape. Some wind is necessary for this type of
ventilation system to function effectively. On still, windless days, fans are necessary to move air through the
greenhouse. The area of the venting should be equal to between 1/5 to 1/6 of the greenhouse floor area.(1)
18. Solar chimneys are passive solar collectors attached to
the highest point on the greenhouse and are combined
with vents or openings on either end of the
greenhouse. The chimney has an inlet that draws warm
air from inside the greenhouse and an outlet that
discharges it to the outdoors. To enhance solar gain
inside the chimney and increase airflow, the inner
surface of the chimney stack is glazed or painted black.
A ventilator turbine added to the top of the chimney
provides an additional force to pull warm air up from
inside the greenhouse.(40)
Thermal storage materials are effective in keeping a
greenhouse cool in summer as well as keeping it warm
in winter. Since these materials absorb heat during the
A solar chimney. (2) day, less heat radiates within the greenhouse when the
sun is shining. When the sun goes down, heat released from the thermal storage materials can be vented out of the
greenhouse.(2)
Removing external shading can also decrease heat build-up within the greenhouse. Shading provided by mature
trees is not recommended. Older books on solar greenhouse design (e.g., 2) argue that deciduous trees can provide
shade in the summer but allow for plenty of sunlight to enter through the glazing in the winter after the leaves are
gone. However, more recent literature notes that a mature, well-formed deciduous tree will screen more than 40%
of the winter sunlight passing through its branches, even when it has no leaves.(31)
Active solar cooling systems include solar air-conditioning units and photovoltaics set up to run standard evaporative
cooling pads. Both are more complex and expensive to equip than passive systems.
Putting It All Together
Designing and building a solar greenhouse can be an exciting and rewarding project. Feel free to rely on the older
literature to provide you with basic siting, design, and construction guidelines. However, incorporating new glazing,
heat storage, and insulating materials into your design can greatly enhance the efficiency of your structure. Several
consulting companies can provide you with blueprints and design assistance, often at a reasonable cost. See the
Resources section for names and contact information for these companies. Of course, you need to weigh the costs of
these new technologies against the value of your greenhouse-grown crops. As you become familiar with the
principles of passive solar design, you may want to experiment with ways of harnessing the power of the sun within
your greenhouse to produce better plants throughout the year.
Back to top
19. References
1. Illinois Solar Energy Association. 2002. Solar Greenhouse. ISEA Fact Sheet #9. Accessed at:
www.illinoissolar.org/
2. Alward, Ron, and Andy Shapiro. 1981. Low-Cost Passive Solar Greenhouses.
National Center for Appropriate Technology, Butte, MT. 173 p.
3. White, Joe. 1991. Growing it in a Sunpit. The Natural Farmer. Winter. p. 14.
4. Thomas, Stephen G., John R. McBride, James E. Masker, and Keith Kemble. 1984. Solar Greenhouses and
Sunspaces: Lessons Learned.
National Center for Appropriate Technology. Butte, MT. 36 p.
5. Bartok, Jr., John W. 2000. Greenhouses for Homeowners and Gardeners. NRAES-137. Cornell University,
Ithaca, NY. 214 p.
6. Giacomelli, Gene A. 1999. Greenhouse coversing systems—User considerations. Cook College. Rutgers
University. Accessed at: http://AESOP.RUTGERS.EDU/~ccea/publications.html
7. Giacomelli, Gene A. 1999. Greenhouse glazings: Alternatives under the sun. Department of Bioresource
Engineering. Cook College. Rutgers University. Accessed at:
http://AESOP.RUTGERS.EDU/~ccea/publications.html
8. Bartok, Jr., John W. 2001. Energy Conservation for Commercial Greenhouses. NRAES-3. Cornell University,
Ithaca, NY. 84 p.
9. BTS. 2001. Passive Solar Design. Technology Fact Sheet. U.S. Department of Energy. Office of Building
Technology, State and Community Programs. Accessed at:
apps1.eere.energy.gov/buildings/publications/pdfs/building_america/29236.pdf
[PDF/232K]
10. Luce, Ben. 2001. Passive Solar Design Guidelines for Northern New Mexico. New Mexico Solar Energy
Association. Accessed at:
www.nmsea.org/Curriculum/Courses/Passive_Solar_Design/Guidelines/Guidelines.htm
11. NREL. 2001. Passive Solar Design for the Home. Energy Efficiency and Renewable Energy Clearinghouse.
National Renewable Energy Laboratory. U.S. Department of Energy. Accessed at:
www.nrel.gov/docs/fy01osti/27954.pdf [PDF/216K]
12. BTS. 2001. Passive Solar Design. Technology Fact Sheet. U.S. Department of Energy. Office of Building
Technology, State and Community Programs. Accessed at: www.nrel.gov/docs/fy01osti/29236.pdf
[PDF/232K]
20. 13. Smith, Shane. 2000. Greenhouse Gardener's Companion: Growing Food and Flowers in Your Greenhouse or
Sunspace. Fulcrum Publishers. 2nd edition. 544 pages. Excerpts accessed at:
www.greenhousegarden.com/energy.htm
14. Nuess, Mike. 1997. Designing and building a solar greenhouse or sunspace. Washington State University
Energy Program.
15. Williams, Sue E., Kenneth P. Larson, and Mildred K. Autrey. 1999. Sunspaces and Solar Porches. The Energy
Event. Oklahoma State Cooperative Extension Service. A hard copy can be purchased via the following
website www.osuums.com/ASPFiles/inventfind.asp?s=.
16. Anon. n.d. Solar Greenhouse Plans and Information. Sun Country Greenhouse Company. Accessed at:
www.hobby-greenhouse.com/FreeSolar.html
17. North Carolina Solar Center. 2000. Do It Yourself Solar Applications: For Water and Space Heating. North
Carolina Solar Center. Energy Division North Carolina Department of Commerce. Accessed at:
www.ncsc.ncsu.edu/information_resources/factsheets/23lowcst.pdf [PDF/713K]
18. NREL. 1999. Building a Better Trombe Wall. National Renewable Energy Laboratory.
19. Edey, Anna. 1998. Solviva: How to Grow $500,000 on One Acre and Peace on Earth. Trailblazer Press,
Vineyard Haven, MA. 225 p.
20. Pin, Nick. 1995. Solar closets in a nutshell. Listserv message. Archived at:
www.ibiblio.org/london/renewable-energy/solar/Nick.Pine/msg00026.html
21. Solar Technologies. Accessed at: www.alaskasun.org/pdf/SolarTechnologies.pdf
(PDF/328K]
22. Gates, Jonathan. 2000. Phase Change Material Research. Accessed at:
http://freespace.virgin.net/m.eckert/index.htm
23. Baird, Stuart, and Douglas Hayhoe. 1983. Passive Solar Energy. Energy Fact Sheet.
24. Korin, E., A. Roy, D. Wolf, D. Pasternak, and E. Rappaport. 1987. A novel passive solar greenhouse based
on phase-change materials. International Journal of Solar Energy. Volume 5. p. 201-212.
25. PCM Thermal Solutions. Underfloor heating. Accessed at: www.pcm-solutions.com/under_app.html
26. TEAP Energy. 2002. PCM Energy Efficiency.
27. EREC. n. d. Phase Change Drywall. EREC Reference Briefs. U.S. Department of Energy. Office of Energy
Efficiency and Renewable Energy. (document no longer available on web)
21. 28. Butler, Nancy J. 1985. A Home Greenhouse—Dream or Nightmare? Weed 'Em and Reap; Feb.-March. MSU
Cooperative Extension Service. Accessed at: www.hobby-greenhouse.com/UMreport.htm
29. Monk, G.J., D.H. Thomas, J.M. Molnar, and L.M. Staley. 1987. Solar Greenhouses for Commercial Growers.
Publication 1816. Agriculture Canada. Ottawa, Canada.
30. Puri, V.M., and C.A. Suritz. 1985. Feasibility of subsurface latent heat storage for plant root zone and
greenhouse heating. American Society of Agricultural Engineers (Microfiche collection) 20 p.
31. NREL. 1994. Sunspace Basics. Energy Efficiency and Renewable Energy Clearinghouse. National Renewable
Energy Laboratory. U.S. Department of Energy. Accessed at:
www1.eere.energy.gov/office_eere/pdfs/solar_fs.pdf [PDF/220K]
32. Thomas, Andrew L., and Richard J. Crawford, Jr. 2001. Performance of an Energy-efficient, Solar-heated
Greenhouse in Southwest Missouri. Missiouri Agricultural Experiment Station. Missouri University College of
Agriculture, Food, and Natural Resources.
33. Nelson, Richard. Sola Roof Garden. Accessed at: http://solaroof.org/wiki/SolaRoof/SolaRoofGarden/
34. Cruickshank, John. 2002. Solar Heated Greenhouses with SHCS. Growing Concerns. Accessed at:
www.sunnyjohn.com/indexpages/shcs_greenhouses.htm
35. Geery, Daniel. 1982. Solar Greenhouses: Underground. TAB Books, Inc.
Blue Ridge Summit, PA. 400 p.
36. Benson Institute. n.d.. The Pankar-huyu and Building a Pankar-huyu. Accessed at:
http://benson.byu.edu/Publication/BI/Lessons/volume22/pankar.html and
http://benson.byu.edu/Publication/BI/Lessons/volume22/building.html
37. Anon. 2002. Greenhouse Glazing. Horticultural Engineering, Rutgers Cooperative Extension, Volume 17, No.
1. Accessed at: www.rosesinc.org/ICFG/Join_ICFG/2002-03/Greenhouse_Glazing.asp
38. Aldrich, Robert A., and John W. Bartok, Jr. 1989. Greenhouse Engineering. NRAES-33. Northeast Regional
Agricultural Engineering Service, Cornell University. 203 p.
39. Hunt, John N. 1988. Saving energy—North Carolina style. Greenhouse Grower. March.
40. Gilman, Steve. 1991. Solar ventilation at Ruckytucks Farm. The Natural Farmer. Winter. p. 15.
Back to top
Resources
22. Kansas State University Recommended High Tunnel Resources. Ted Carey. 2008.
K State Plans for 4-season hoophouses
www.hightunnels.org
Note: www.hightunnels.org has links to suppliers and multiple sources of information-including the high tunnels
listserv, Penn State Web site, and construction designs. The hightunnel listserv allows participants to ask questions of
all members of the list. Complete archives are stored on-line.
Blomgren, T., and T. Frisch. 2007. High Tunnels: Using low-cost technology to increase yields, improve quality and
extend the season. University of Vermont Center for Sustainable Agriculture.
www.uvm.edu/sustainableagriculture/hightunnels.html
Coleman, Eliot. 1998. The Winter Harvest Manual.
Order from: Four Season Farm, 609 Weir Cover Road, Harborside, ME. $15.00.
Growing for Market. [n.d.] Hoophouse handbook. Fairplain Publications, Lawrence, KS.
Order from: Fairplain, P.O. Box 3747, Lawrence, KS 66046.
www.growingformarket.com; 800-307-8949. Much of the content reprinted from Growing for Market.
Heidenreich, C. et al. 2007. High Tunnel Raspberries and Blackberries. Cornell University.
www.fruit.cornell.edu/Berries/bramblepdf/hightunnelsrasp.pdf
Jett, Lewis. High Tunnel Tomato Production. University of Missouri Extension. Pub. MI70.
Jett, L. High Tunnels Melon and Watermelon Production. University of Missouri Extension. Pub. M173.
Lamont et al. 2004. Production of Vegetables, Strawberries and Cut Flowers Using Plasticulture. NRAES-133. Ithaca,
NY.
Penn State High Tunnel Production Manual. 2004.
www.plasticulture.org/publications/tunnel.pdf. $31.00.
Wiediger, Paul and Alison. [n.d.] Walking to Spring.
Order from: Au Naturel Farm, 3298 Fairview Church Road, Smiths Grove, KY 42171. $18.50.
Books
Solar Greenhouses
Energy Conservation in Greenhouses
Passive Solar Home Design
Note: Many of the books listed below are out of print. You may be able to locate these books at a public library or in
a good used bookstore. Bibliofind is an excellent, searchable Web site where many used and out-of-print books can
be located.
Solar Greenhouses
Anon. 1980. A Solar Adapted Greenhouse Manual and Design. Miller-Solsearch, Charlottetown, PEI, Canada.
Anon. 1979. The Canadian Solar Home Design Manual. Overview,
Wolfville, Nova Scotia. 71 p.
Babcock, Joan, et al. 1981. A Place in the Sun: A Guide to Building an Affordable Solar Greenhouse. R.J.K. Solar,
Gillette, NJ. 28 p.
23. Craft, Mark A. (Editor). 1983. Winter Greens: Solar Greenhouses for Cold Climates.
Firefly Books. Scarborough, Ont. 262 p. (Out of Print).
Clegg, Peter. 1978. The Complete Greenhouse Book: Building and Using Greenhouses from Cold-Frames to Solar
Structures. Storey Books. Pownal, VT. 280 p. (Out of print).
Conserver Society Products Cooperative. 1979. Solar Greenhouse Workbook.
Conserver Society Cooperative, Ottawa, Canada. 43 p.
DeKorne, James B. 1992. The Hydroponic Hot House: Low-Cost, High Yield Greenhouse Gardening. Breakout
Productions, Incorporated 178 p.
An illustrated guide to alternative-energy greenhouse gardening. It includes directions for building several different
greenhouses.
Edey, Anna. 1998. Solviva: How to Grow $500,000 on One Acre and Peace on Earth. Trailblazer Press, Vineyard
Haven, MA. 225 p.
One of few recent books written on solar greenhouses. Available for $35 from:
Solviva
RFD 1 Box 582
Vineyard Haven, MA 02568
508-693-3341
508-693-2228 FAX
solviva@vineyard.net
Ellwood, Charles C. How to Build and Operate Your Greenhouse: Growing Methods, Hydroponics, Nutrient Formulas,
Plans, Costs, Heating and Cooling, Introduction to Solar heating. H.P. Books. Tucson, AZ. 144 p. (Out of print).
Freeman, Mark. 1997. Building Your Own Greenhouse. Stackpole Books,
Mechanicsburg, PA. 208 p.
A guide to designing and constructing cold frames, free-standing greenhouses, and attached to the house solar
greenhouses. Available for $18.95 from:
Stackpole Books
5067 Ritter Rd.
Mechanicsburg, PA 17055
800-732-3669
Fontanetta, John. 1979. Passive Solar Dome Greenhouse Book. Storey Books.
Pownal, VT. (Out of print).
24. Fuller, R.J. 1992. Solar Greenhouses for the Home Gardener. Victorian Dept. of Food and Agriculture, Melbourne,
Australia. 27 p.
Geery, Daniel. 1982. Solar Greenhouses: Underground. TAB Books, Blue Ridge Summit, PA. 400 p.
Focuses on earth-sheltered solar greenhouse structures. Good information on design, function, construction, and
operation of greenhouses. Many useful tables and charts. (Out of print).
Hayes, John (ed.). 1979. Proceedings from the Conference on Energy-Conserving, Solar-Heated Greenhouses. Held
in Plymouth, MA, April, 1979. New England Solar Energy Association, Brattleboro, VT. 328 p.
Head, William. 1984. Fish Farming in Your Solar Greenhouse. Amity Foundation, Eugene, OR. 50 p. (Out of print).
Magee, Tim. 1979. A Solar Greenhouse Guide for the Pacific Northwest.
Ecotope, Seattle, WA. 91 p.
Available for $6 from:
Ecotope
2812 E. Madison
Seattle, WA 98112
206-322-3753
Mazria, Edward. 1979. The Passive Solar Energy Book. Rodale Press, Emmaus, PA. 435 p. (Out of print, but usually
available from used book sellers).
McCullagh, James C. (ed.) 1978. The Solar Greenhouse Book. Rodale Press, Emmaus, PA. 328 p.
Comprehensive overview of small attached, pit, and free-standing solar greenhouses. Out of print, but usually
available from used booksellers.
Monk, G.J., D.H. Thomas, J.M. Molnar, and L.M. Staley. 1987. Solar Greenhouses for Commercial Growers.
Publication 1816. Agriculture Canada, Ottawa, Canada. 48 p.
Nearing, Helen, and Scott Nearing. 1977. Building and Using Our Sun-Heated Greenhouse: Grow Vegetables All Year-
Round. Storey Books, Pownal, VT. 148 p. (Out of print).
Shapiro, Andrew. 1985. The Homeowner's Complete Handbook for Add-On Solar Greenhouses and Sunspaces.
Rodale Press, Emmaus, PA. 355 p.
Updates and expands on material in The Solar Greenhouse Book (see above). (Out of print).
Smith, Shane. 1982. The Bountiful Solar Greenhouse. John Muir Publications. Santa Fe, NM. 221 p. (Out of print).
Stone, Greg. 1997. Building a Solar-Heated Pit Greenhouse. Storey Communications,
Pownal, VT. 32 p. (Out of print).
25. Strickler, Darryl J. 1983. Solarspaces : How (and Why) to Add a Greenhouse, Sunspace, or Solarium to Your Home.
Van Nostrand Reinhold Co., New York, NY. 154 p. (Out of print).
Taylor, Ted M. 1999. Secrets to a Successful Greenhouse and Business : A Complete Guide to Starting and Operating
A High-Profit Organic or Hydroponic Business That Benefits the Environment. GreenEarth Publishing, Melbourne, FL.
280 p.
Includes solar greenhouse design plans as well as greenhouse operation and business development information.
Ordering information available at: www.greenhouse.net
Thomas, Stephen G., John R. McBride, James E. Masker, and Keith Kemble. 1984. Solar Greenhouses and Sunspaces:
Lessons Learned. National Center for Appropriate Technology. Butte, MT. 36 p. (Out of print).
Williams, T. Jeff, Susan Lang, and Larry Hodgson. 1991. Greenhouses: Planning, Installing and Using Greenhouses.
Ortho Books, San Ramon, CA. 112 p.
Yanda, William F. 1976. An Attached Solar Greenhouse. Lightning Tree Press, Boulder, CO. 18 p. (Out of print).
Yanda, William F., and Rick Fisher. 1980. The Food and Heat Producing Solar Greenhouse: Design, Construction, and
Operation. John Muir Publishing, Santa Fe, NM. 208 p.
(Out of print).
Energy Conservation in Greenhouses
Aldrich, Robert A., and John W. Bartok, Jr. 1989. Greenhouse Engineering. NRAES-33. Cornell University, Ithaca, NY.
203 p.
Provides a comprehensive treatment of the design and construction of medium- to large-scale greenhouses, with
over 60 tables and 100 diagrams. $30.
Bartok, Jr., John W. 2001. Energy Conservation for Commercial Greenhouses. NRAES-3. Cornell University, Ithaca,
NY. 84 p.
Reviews the merits and limitations of current energy-conservation strategies for commercial greenhouses. Topics
covered include principles of heat loss, site selection and modification, construction materials, insulation, fuels and
heating, ventilation and cooling, space utilization, utilities, strategies for reducing trucking costs, and managing for
efficiency.
Bartok, Jr., John W. 2000. Greenhouses for Homeowners and Gardeners. NRAES-137. Cornell University, Ithaca, NY.
214 p.
26. Covers every aspect of designing and constructing a home greenhouse. Eight chapters discuss the following topics:
greenhouse basics, selecting a greenhouse, greenhouse planning, framing materials and glazing, greenhouse layouts
and equipment, the greenhouse environment, window greenhouses and growth chambers, and garden structures.
The three books listed above are available from:
Natural Resource, Agriculture, and Engineering Service (NREAS)
152 Riley-Robb Hall
Ithaca, New York 14853-5701
607-255-7654
607-254-8770 FAX
NRAES@cornell.edu
Bond, T.E., J.F. Thompson, and Ray F. Hasek. 1985. Reducing Energy Costs in California Greenhouses. Leaflet
21411. Cooperative Extension University of California. 24 p.
Passive Solar Home Design
Anderson, Bruce, and Malcolm Wells. 1981. Passive Solar Energy: The Home-owner's Guide to Natural Heating and
Cooling. Brick House Pub. Co. 197 p.
Crosbie, Michael J. (ed.) 1998. The Passive Solar Design and Construction Handbook.
John Wiley and Sons Ltd., New York. 291 p.
Creech, Dennis B. 1988. Homeowner's Guide to Energy Efficient and Passive Solar Homes. DIANE Publishing Co.
Kachadorian, James. 1997. The Passive Solar House: Using Solar Design to Heat and Cool Your Home. Chelsea Green
Publishing Co. White River Junction, VT $25.
Available from The Solar Energy Organization Web page.
Levy, M. Emanuel, Deane Evans, and Cynthia Gardstein. 1983. The passive solar construction handbook: featuring
hundreds of construction details and notes, materials specifications, and design rules of thumb. Rodale Press,
Emmaus, PA. 328 p.
Back to top
Articles, Fact Sheets, and Web Sites
Solar Greenhouse Designs and Consultation
Greenhouse Glazing
Greenhouse Curtains
Solar Chimneys
27. Phase-Change Materials
General Greenhouse Information
Greenhouse Technical and Trade Publications
Solar Energy Organizations: National
Solar Energy Organizations: State
Solar Greenhouse Designs and Consultation
The Bioshelter at Three Sisters Farm
The bioshelter includes a solar greenhouse, poultry housing, potting room, seed and tool storage, an equipment
storage "barn," a kitchen for packing produce, compost bins, a reference library and living spaces. A full report of the
bioshelter design costs $8.00. Three Sisters Permaculture Design also offers consultation on solar greenhouse design,
construction and management.
The Green Greenhouse
An excellent site, funded partially by the Northeast SARE, provides detailed design blueprints, materials list,
construction suggestions, and performance information for a solar greenhouse.
Growing Concerns, Unlimited. Solar Greenhouses
Provides design and construction consulting services for building solar greenhouses and homes. Specializes in
subterranean solar heat systems.
Hobby Greenhouse Association
Sells a Directory of Manufacturers: Hobby Greenhouses, Solariums, Sunrooms, and Window Greenhouses for $2.50.
Has links to many greenhouse manufacturers' Web pages. A one-year membership to the association costs $15 and
includes a subscription to Hobby Greenhouse, a quarterly magazine, and Hobby Greenhouse News, a quarterly
newsletter.
Hobby Greenhouse Association
8 Glen Terrace
Bedford, MA 01730-2048
781-275-0377
Passive Solar Greenhouse
Provides consulting services and passive solar greenhouse plans that have passed building codes for New Mexico.
Blueprints include lists of materials and where to purchase them.
Solar Components Corporation
Solar greenhouse kits as well as blueprints and materials for "build-your-own" solar greenhouses.
Solar Components Corporation
121 Valley Street
28. Manchester, NH 03103
603-668-8186
Sundance Supply
Provides information on greenhouse design and installation. Sells materials needed for constructing and maintaining
greenhouses.
Sunglo Solar Greenhouses
214 21st Street SE
Auburn, WA 98002
800-647-0606
Free catalog of greenhouse kits available.
Greenhouse Glazing
Giacomelli, Gene A. 1999. Greenhouse coversing systems - User considerations. Greenhouse glazings: Alternatives
under the sun. Cook College. Rutgers University.
http://AESOP.RUTGERS.EDU/~ccea/publications.html
Giacomelli, G.A., and W.J. Roberts. 1993. Greenhouse covering systems. HortTechnology. Volume 3, no. 1. p. 50-58.
Roberts, W.J. 1989. Greenhouse glazing. In: K.V. Garzoli (ed.) Energy Conservation and Solar Energy Utilization in
Horticultural Engineering. Acta horticulturae. Volume 257. p. 161-168. Ordering information at:
www.actahort.org/books/257/index.htm
Meyer, J. 1985. Greenhouse Construction and Covering Materials. ISHS Acta Horticulturae 170. Ordering information
at: www.actahort.org/books/170/
Efficient Windows Collaborative
National Festration Council. 2002
Greenhouse Curtains
National Greenhouse Manufactures Association. Helpful Hints: Internal and External Greenhouse Curtain Systems
[PDF/125K]
Agri-tech. Energy Curtain
FAQs—Internal & External Greenhouse Curtain Systems. Griffin Greenhouse and Nursery Supply
National Greenhouse Manufacturers Association
29. Solar Chimneys
Anon. 1986. Solar chimney for low-cost desert cooling. Popular Science. May. p. 16B-17C.
Abrams, Don. 1984. The latest on solar chimneys. Rodale's New Shelter. August. p. 10-11.
Abrams, Donald W. 1986. Low-Energy Cooling: A Guide to the Practical Application of Passive Cooling and Cooling
Energy Conservation Measures. Van Nostrand Reinhold Co., New York, NY. p. 126-131, 150-161.
Burton, John, and Jeff Reiss. 1981. Project: A solar chimney. p. 623-627. In: Joe Carter (ed.) Solarizing Your Present
Home. Rodale Press, Emmaus, PA.
Cunningham, W.A., and T.L. Thompson. 1988. Passive greenhouse cooling.
Greenhouse Grower. April. p. 19-20.
Phase-change Materials
Verner, Carl. 1997. Phase Change Thermal Energy Storage.
http://freespace.virgin.net/m.eckert/carl_vener's_dissertation.htm
General Greenhouse Information
Abraham, Doc and Katy. 1993. What to look for in a greenhouse. Consumers' Research. January. p. 31-35.
Good introduction to greenhouses in general.
Dickerson, Lizzy. 1992. The stone-built, bermed greenhouse. Maine Organic Farmer & Gardener. May-June. p. 16-17.
Hofstetter, Bob. 1989. Tunnels of plenty. The New Farm. November-December. p. 36-39.
Hofstetter, Bob. 1990. The New Farm's greenhouse guide. The New Farm. September-October. p. 32-36.
von Zabeltitz, Christian. 1990. Greenhouse construction in function of better climate control. Acta Horticulturae Vol.
263. p. 357-366
Greenhouse Technical and Trade Publications
Acta Horticulturae
Journal of the International Society for Horticultural Science
ISHS Secretariat
P.O. Box 500
3001 Leuven 1, Belgium
30. Greenhouse Grower
Meister Publishing Company
37733 Euclid Ave.
Willoughby, OH 44094
216-942-2000
GM Pro (formerly Greenhouse Manager)
Branch-Smith Publishing
120 St. Louis Ave.
Fort Worth, TX 76101
800-433-5612
817-882-4121 FAX
www.greenbeam.com
NM Pro (formerly Nursery Manager)
Branch-Smith Publishing
120 St. Louis Ave.
Fort Worth, TX 76101
800-433-5612
817-882-4121 FAX
www.greenbeam.com
GrowerTalks
Ball Publishing
335 N. River Street
PO Box 9
Batavia, IL 60510-0009 USA
630-208-9080
630-208-9350 FAX
Greenhouse Product News
Scranton Gillette Communications, Inc.
380 E. Northwest Hwy.
Des Plaines, IL 60016-2282
708-290-6622
Solar Energy Organizations: National
American Solar Energy Society
2400 Central Ave., G-1
31. Boulder, CO 80301
303-443-3130
Publishes Solar Today magazine and an annual membership directory; $70 annual membership fee.
National Renewable Energy Laboratory. Energy Efficiency and Renewable Energy. U.S. Department of Energy.
Passive Solar Heating, Cooling and Daylighting.
www.eere.energy.gov/de/cs_passive_solar.html
Fact sheets include:
Passive Solar Design for the Home
U.S. Department of Energy. Office of Building /Technology, State and Community Programs. Publications.
Fact sheets include:
Passive Solar Design
The Solar Energy Research Facility
Renewable Energy Policy Project and Center for Renewable Energy and Sustainable Technology
Links to national, state, and international solar energy associations.
Database of State Incentives for Renewable Energy (DSIRE)
Links to state, local, utility, and selected federal incentives that promote renewable energy.
Solar Energy Organizations: State
Illinois Solar Energy Association
Indiana: Midwest Renewable Energy Association
New Mexico Solar Energy Association
North Carolina Solar Center
Other sources of solar greenhouse factsheets have, in the past, included Oklahoma State Cooperative Extension
Service, the Solar Energy Association of Oregon, the Texas State Energy Conservation Office, and the Texas Solar
Energy Society. The best way to find current information on such organizations is by doing a Web search.
Back to top
Computer Software
EREC. n. d. Computer Software for Solar Energy Analysis and System Design. EREC Reference Briefs. U.S.
Department of Energy. Office of Energy Efficiency and Renewable Energy.
www.eere.energy.gov/buildings/tools_directory/software.cfm/ID=88/
33. Această listă de resursă discută despre principiile de bază ale proiectare
solare cu efect de seră, precum şi opţiuni diferite de construcție de
materiale. Cărţi, articole şi site-uri Web şi programe de calculator
relevante pentru proiectare de seră solare sunt furnizate într-o listă de
resursă.
Cuprins
Kansas City Center pentru agricultură
urbane.
Foto: NCAT
Introducerea
Principiile de bază ale solare cu efect de seră Design
Solare cu efect de seră Designs
Solare de absorbție de energie termică
Solare de stocare de căldură
Izolare
Ventilație
Pune-O împreună
Referinţe
Resurse
o Cărţi
o Articole, fișele şi site-uri Web
o Programe de calculator
Introducerea
Începând cu 2000, U.S. cu efect de seră cultivatorilor au din ce în ce adoptat tuneluri de mare ca tehnologie cu efect
de seră solare preferată. Rame rigide și geamurile sunt încă comune în regiuni ale Europei și controlate de clima
operaţiunile în Mexic şi Caraibe care produc de acri de culturilor de iarnă pentru piețele din America de Nord. (Pentru
mai multe pe tehnologia de climat controlat, consultaţi Linda Calvin și Roberta Cook. 2005. "Tomate de seră
Schimbarea dinamica a industriei din America de Nord de tomate proaspete." AmberWaves. Aprilie. Vol. 3, nr. 2.).
Toate sere colecta energia solară. Serele solare sunt concepute pentru a colecta energia solară în timpul zile insorite
dar, de asemenea, pentru a stoca energie termică pentru folosirea pe timp de noapte sau în timpul perioadelor când
este tulbure. Acestea fie poate sta singur sau se anexează case sau hambare. O seră solare pot fi o groapă subteran,
o structură de tip de magazie sau un hoophouse. Producătorii pe scară largă folosesc nefixată solare sere, în timp ce
ataşat structurile sunt în primul rând folosite de cultivatori de scară de acasă.
Pasivă solare sere sunt adesea bune alegeri pentru cultivatorii mici, deoarece acestea sunt un cost-eficient mod
pentru agricultorii să extindă sezonului de creştere. În rece climate sau în zonele cu perioade lungi de vreme tulbure,
încălzire solare pot trebuie să fie completate cu un gaz sau un sistem de încălzire electrică necesară protejarea
34. plantelor împotriva frigului. Serele solare activă utilizaţi suplimentare de energie pentru a muta solare de aer încălzit
sau apă din zonele de depozitare sau colectarea alte regiuni de seră. Utilizarea solare electrice (fotovoltaice) sisteme
pentru serele de încălzire nu este rentabilă decât dacă sunt producătoare de culturi de mare valoare.
Riscuri datorate turbulenţe crescut de vreme:
Grindină
Tornados
Vânturile puternice liniară
Acumulării de zăpadă, gheaţă
Majoritate de cărţi şi articole despre sere solare stil vechi au fost publicate în anii 1970 și 1980. De atunci, mare parte
din acest material a plecat din imprimare şi unele dintre editorii nu mai sunt în afaceri. În timp ce informaţii de
contact pentru companii si organizatii enumerate în aceste publicaţii este probabil neactualizat, unele dintre informații
tehnice conţinute în ele este încă relevante.
Cele mai noi forma de seră solare, adoptat pe scară largă de către producătorii de U.S., este mare de tuneluri.
Termenul pentru geamurile, astfel cum este utilizat în prezenta publicație, include trimitere la Îmbrăcămințile de
polietilenă pentru caselor cercui.
Adesea publicaţii afară de imprimare poate fi găsit în librăriile utilizate, biblioteci, şi prin programul de inter-library de
împrumut. Unele publicaţii sunt de asemenea disponibile pe Internet. Bibliofind este un excelent, căutabil site Web
unde multe folosite şi cărţi afară de imprimare poate fi localizată.
După cum aveţi de gând să construiască sau remodela o seră solare, nu limita dumneavoastră de cercetare de cărţi şi
articole care în mod specific discuta "solare sere." Deoarece toate sere colecta energia solară și necesitatea de a
moderată fluctuațiilor de temperatură pentru creșterea plantei optimă, mult de informații asupra gestionării de seră
"standard" este doar de relevante pentru sere solare. De asemenea, mai multe informaţii despre pasivă solare
încălzire pentru casele este de asemenea pertinente pentru încălzire solare pasive pentru sere. Aşa cum te uiţi prin
cărţi şi articole despre generale cu efect de seră proiectarea și construcția, veţi găsi informaţii relevante pentru sere
solare în capitolele sau sub titlurile de subiect care discuta:
conservarea energiei
materialele pentru sticla
sisteme de încălzire podea
materiale izolante
metode de ventilație
În cărți sau articole pe pasivă solare încălzire în casele sau alte clădiri, puteţi găsi informaţii utile pe sere solare prin
căutarea de capitole sau titlurile de subiect care examinează:
orientarea solare
35. materiale de absorbție căldură
schimb de căldură prin "faza-schimbare" sau "materiale de stocare căldură latentă"
Această listă de resursă actualizat include listări de cărţi, articole şi site-uri Web care se concentrează în special
asupra solare sere, precum şi pe subiecte enumerate mai sus.
Conexe ATTRA publicaţii
Sezonul extinderea tehnici pentru piața gradinari
Productia ecologica de legume cu efect de seră
Cu efect de seră şi resursele de producţie vegetală Hydroponic pe Internet
Potting adaos pentru productia ecologica de certificate
Management integrat al daunatorilor pentru culturile cu efect de seră
Plante: Productia ecologica, cu efect de seră
Conectaţi productia de rasaduri pentru sistemul ecologic
Compost de încălzit sere
Zona de rădăcină de încălzire pentru culturile cu efect de seră
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Principiile de bază ale solare cu efect de seră Design
Serele solare diferă de sere convenţionale în următoarele patru moduri.(1) Solar sere:
au geamuri orientate spre primi căldură solare maximă în timpul iernii.
Utilizaţi căldură depozitarea materialelor pentru a reține căldura solară.
au cantităţi mari de izolare în cazul în care există foarte puţin sau nu lumina solară directă.
Utilizaţi material geamurile şi metode de instalare geamurile care minimiza pierderea de căldură.
se bazează în principal pe ventilație naturală de vara de răcire.
Înţelegerea aceste principii de bază ale seră solare proiect vă va asista în proiectarea, construcţia şi întreţinerea o
structură eficiente energetic. De asemenea, puteţi utiliza aceste concepte care vă ajută să căutaţi informaţii
suplimentare, fie de pe "Web," în jurnale sau în cărţi la librăriile şi biblioteci.
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Solare cu efect de seră Designs
Ataşat sere solare sunt lean-to structuri care formează o cameră jutting de la o casă sau hambar. Aceste structuri
spațiu pentru transplanturile, ierburi sau cantități limitate de hrană. Aceste structuri de obicei au un design pasivă
solare.
36. Tancuri serele solare sunt suficient de mare pentru producția comercială de culturi, legume sau plante aromatice.
Există două primar desene sau modele pentru serele solare tancuri: tipul de magazie și hoophouse. Un tip de
magazie solare seră este orientată spre are axa lungă să fie difuzate de la est la vest. Peretele de Sud-confruntă este
lustruit să colecteze valoarea optimă a energiei solare, în timp ce wall nord-cu care se confruntă este well-insulated
pentru a preveni pierderea de căldură. Această orientare este în contrast cu o seră convenţionale, care are său
acoperiş execută Nord-Sud pentru a permite distribuția luminii uniforme pe toate laturile de plante. Pentru a reduce
efectele săraci distribuția luminii într-o seră orientate spre est-vest, peretele nord este acoperit sau pictat cu
reflectorizant.(2)
Tancuri magazie de tip solare sere(2)
Pentru ierni reci, latitudinile medii ale emisferei nordice, și utilizarea tot parcursul anului:
• Nord de abrupt acoperiş avânt la unghiul de soarele de vară cea mai mare de reflecţie de
lumină întregul maximă pe plante;
• Zidul de Nord verticale pentru stashing de căldură de stocare.
• 40-60 ° înclinat acoperiş Sud geam.
• verticală kneewall suficient de mare pentru a se potrivi plantare paturi si zapada alunece de
pe acoperiş.
• sfârşitul pereți parțial lustruit pentru lumina adăugată.
• Acoladă Institutul de proiectare continuă Nord acoperiş pantă în jos la sol (eliminarea zidul
de Nord), care să permită mai multe zona plantare în pământ, dar nici un depozit de căldură
de perete de Nord.
Pentru ierni reci, Mijlociu latitudini U.S. şi year-round utilizaţi (similar cu proiectarea
popularizat de Institutul de tehnologie interne, consultaţi resurse pentru planurile şi adresa):
• 45-60 ° Nord acoperiş panta.
• Zidul de Nord verticală pentru depozitarea suprapunere de căldură.
• 45 ° Sud acoperiş geam.
• verticală kneewall.
• parte din ziduri de sfârşitul lustruit pentru lumina suplimentare.
Iernile sunt atenuate, sudul U.S. latitudini și utilizarea tot parcursul anului, în care mai puţin
de căldură de stocare este necesar:
• 45-70 ° Nord acoperiş panta — acoperiş panta steeper și zidul de Nord mai scurte, mai
puţin spaţiu este necesară pentru stivuirea termice de stocare.
• acoperiş poate extinde în jos la pământ, eliminarea kneewall înapoi în cazul în care
depozitarea nu este utilizarea.
• 20-40 ° Sud acoperiş geam.
• față kneewall fel de mare ca este nevoie de acces la paturi in fata.
• majoritatea sfârşitul pereţi lustruit pentru lumina suplimentare.
Hoophouses tancuri sunt structuri simetrice, rotunjite. Spre deosebire de tipul de magazie solare sere, acestea nu au
o partea de Nord izolate. Solarizare aceste structuri implică practici care îmbunătăţesc absorbție și distribuție a
energiei termice solare introducerea ei. Acest lucru implică de obicei colecţie de căldură solare în sol sub podea, într-
un proces numit pământ termice stocare (ETS), precum și în alte materiale de stocare, cum ar fi apă sau roci
37. dislocate. Izolare a peretelui cu efect de seră este important pentru minimizarea pierderii de căldură. Sisteme de
absorbție de căldură și metodele de izolare sunt discutate în detaliu în următoarele secţiuni.
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Solare de absorbție de energie termică
Doi factori cele mai critice care afectează cantitatea de căldură solare o seră este capabil să absoarbă sunt:
Poziţia sau locaţia cu efect de seră în raport cu soarele
Tipul de geam materialul utilizat
Orientarea solare
Deoarece energie de la soare este mai puternică pe latura de Sud a unei clădiri, geamuri pentru serele solare ideal ar
trebui să se confruntă Sud adevărat. Cu toate acestea, în cazul în care copaci, Munţii sau alte clădiri bloca calea
soarelui atunci când seră este într-o orientare Sud adevărat, o orientare în termen de 15 ° la 20 ° de Sud adevărat va
oferi aproximativ 90% din captură solare de o orientare Sud adevărat. Latitudine de locaţia și locația potenţiale
obstacole pot solicita, de asemenea, că vă ajusta orientarea dumneavoastră cu efect de seră uşor la south adevărat
pentru a obţine câştig optimă de energie solară.(2) Cultivatorii de unele recomanda orientare de seră oarecum la
sud-est pentru a obţine cel mai bun câştig solare în primăvara, mai ales dacă seră este utilizată în principal să
crească transplanturi.(3) Pentru a determina orientarea corectă pentru clădiri solare în zona dumneavoastră, vizitează
programul de diagramă soare la laboratorul de monitorizare Universitatea din Oregon solare radiații pagina Web.
Trebuie să ştiţi dumneavoastră latitudine, longitudine şi fusul orar pentru a utiliza acest program.
Calea solare la 40 ° latitudine nordică (2)
38. Panta Material pentru geamurile
În plus faţă de orientare nord-sud, cu efect de seră geamuri trebuie să fie corect înclinat să absoarbă cea mai mare
cantitate de căldură de la soare. Un bun empiric este pentru a adăuga 10 ° sau 15 ° latitudine site-ul pentru a obţine
unghiul de buna. De exemplu, dacă sunteţi în California de Nord sau Illinois centrală la 40 ° Nord latitudine, geamul
trebuie să fie înclinat la unui 50 ° de unghiul de 55 ° (40 ° + 10 ° sau 15 °).(4)
Geamuri
Materialele folosite în sere solare geamurile ar trebui să permită cea mai mare cantitate de energie solară să intre în
de seră, în timp ce minimizarea pierderii de energie. În plus, creșterea plantei bun presupune că materialele pentru
geamurile permite un spectru naturale de radiaţii photosynthetically activă (PAR) pentru a intra. Stare brută-
suprafață sticlă, dublu strat rigide din material plastic şi fiberglass lumină difuză, în timp ce clar sticlă transmite
lumina directă. Deşi plantele cresc bine cu lumină directă şi difuze, lumină direct prin geamurile subdivizate după
sprijină structurale cauze mai multe umbre şi creșterii plantelor inegala. Lumină difuză care trece prin geamurile
evens afară umbre cauzate de susţine structurale, care rezultă în mai multe chiar creșterii plantelor.(5, 6)
Multe noi cu efect de seră materialele pentru geamurile au apărut în ultimele decenii. Materiale plastice acum sunt
dominante tip de geam utilizate în sere, cu weatherability aceste materiale fiind îmbunătăţită prin radiaţii ultraviolete
degradare inhibitori, radiații infraroşu (IR) de atenuare a șocurilor, picurare anti-condensation suprafețelor și radiația
unic transmiterea proprietăţi.(7)
Metoda utilizată pentru montarea material geamurile afectează suma de pierdere a căldurii.(8), De exemplu,
crăpături sau găuri cauzate de montare va permite căldură să scape, în timp ce diferențele de lățimea spațiului aerian
între două smalțuri va afecta retenţie de căldură. Instalare şi schelet pentru anumite materiale de geamuri, cum ar fi
acrylics, trebuie să țină seama de extinderea și contracția cu cald si rece vremea lor.(7) Ca regulă generală, o seră
solare ar trebui să aibă de aproximativ 0,75 la 1,5 metri pătraţi de geamuri pentru fiecare pătrat picior de podea
spaţiu.(1)
Tabelul 1. Caracteristicile de geamuri
Sticlă — singur strat Fabrică sigilate sticlă dublă
Lumina transmiterea *: 85-90% Lumina transmiterea *: 70-75%
Bolizi **: 0.9 Bolizi **: dublu strat 1.5-2.0, low-e 2.5
Avantajele: Avantajele:
• Durată nedeterminată dacă nu rupt • Durată nedeterminată dacă nu rupt
• Temperat sticlă este mai puternic şi • Pot fi utilizate în zonele cu temperaturilor de
necesită mai puţine suport baruri îngheț
Dezavantaje: Dezavantaje:
• Fragile, uşor rupt • Grele
• Nu poate rezista la greutatea de zăpadă • Clar sticlă difuze lumină
39. • Necesită numeroase sprijină • Dificil pentru a instala, necesită definirea precisă
• Clar sticlă difuze lumină
Polietilenă — singur strat Polietilenă — strat dublu
Lumina transmiterea *: 80-90%-material Lumina transmiterea *: 60-80%
nou Bolizi ** dublu filme: 5 ml filmul 1.5, 6 ml filmul
Bolizi **: singur filmul 0.87 1.7
Avantajele: Avantajele:
• IR filme au tratament pentru a reduce • Pierderea de căldură redusă semnificativ atunci
pierderea de căldură când se utilizează un ventilator pentru a oferi un
• Nu picătură filme sunt tratate pentru a spaţiu aerian între două straturi
rezista condensare • IR filme au tratament pentru a reduce pierderea
• Tratament cu acetat de vinil etil rezultate în de căldură
rezistența la cracare la rece şi de rupere • Nu picătură filme sunt tratate pentru a rezista
• Uşor de instalat, precise nu judicioase condensare
necesare • Tratament cu acetat de vinil etil rezultate în
• Material geamurile de costul mai mic rezistența la cracare la rece la rupere
• Uşor de instalat, precise nu judicioase necesare
Dezavantaje: • Cel mai mic cost material de geamuri
• Uşor rupt
• Nu poate vedea prin Dezavantaje:
• Polietilenă rezistentă la UV dureaza numai • Uşor rupt
1-2 ani • Nu poate vedea prin
• Scade de transmisie a luminii în timp • Polietilenă rezistentă la UV dureaza numai 1-2
• Extinderea şi sag în vremea calda, apoi ani
micşora în vreme rece • Scade de transmisie a luminii în timp
• Extinderea şi sag în vremea calda, apoi micşora
în vreme rece
Polietilenă — cartonului ondulat Stratificată acrilic/poliester filmul — strat
densitate mare dublu
Lumina transmiterea *: 70-75% Lumina transmiterea *: 87%
Bolizi **: 2.5-3.0 Bolizi **: 180 %
Avantajele: Avantajele:
• Mucegai, chimice și rezistente la apă • Combină weatherability de acrilic cu
• Nu galben temperaturi ridicate ale serviciilor de poliester
• Poate dura 10 ani sau mai mult
Dezavantaje:
n/a Dezavantaje:
• Arcrylic sticlă extinde şi contract considerabil;
încadrare are nevoie pentru a permite această
schimbare în mărimea
40. • Nu rezistente la foc
Impactul modificate acrilic — strat dublu Fibra întărite de plastic (FRP)
Lumina transmiterea *: 85% Lumina transmiterea *: 85-90%-material nou
Bolizi **: singur strat 0.83
Avantajele:
• Nu degradate sau decolorate în lumină UV Avantajele:
• Forţa de impact ridicat, bun pentru locaţii • Natura translucide acest material diffuses şi
cu grindină distribuie uniform lumină
• Tratate de Tedlar panouri sunt rezistente la
Dezavantaje: vremea, lumina soarelui şi acizi
• Arcrylic sticlă extinde şi contract • Puteţi ultimii 5-20 ani
considerabil; încadrare are nevoie pentru a
permite această schimbare în mărimea Dezavantaje:
• Rezistente nu la foc • Scade de transmisie a luminii în timp
• Rezistenţă săraci de la vremea
• Cel mai inflamabile materialele vitrajelor rigide
• Abilitatea de izolare nu produce zăpadă pentru a
topi
Policarbonat — dublu perete rigide din Policarbonat filmul — triplu şi quad perete
material plastic rigide din material plastic
Lumina transmiterea *: 83% Lumina transmiterea *: 75%
Bolizi **: 6 mm 1.6, 1.7 de 8 mm Bolizi ** triplu pereţi: 8 mm 2.0-2.1, 16 mm 2.5
Bolizi ** quad perete: 6 mm 1.8, 8 mm 2.1
Avantajele:
• Cele mai rezistente la foc de plastic Avantajele:
materialele vitrajelor • Cele mai rezistente la foc de plastic materialele
• Rezistentă la UV vitrajelor
• Foarte puternic • Rezistentă la UV
• Uşoare • Foarte puternic
• Uşor de tăiat şi a instala • Uşoare
• Oferă performanţă bună pentru 7-10 ani • Uşor de tăiat şi a instala
• Oferă performanţă bună pentru 7-10 ani
Dezavantaje:
• Pot fi scumpe Dezavantaje:
• Nu clar, translucide • Pot fi scumpe
• Nu clar, translucide
Surse: (2, 6, 7, 13, 14)
* Notă că schelet scade cantitatea de lumină care pot trece printr- şi fi disponibil ca energie
solară
** Bolizi este o măsură de comune de izolare (hr°Fsq.ft/BTU)
41. Aveţi nevoie pentru a înţelege patru numere în selectarea geamuri pentru serele solare. Două numere descrie randamentul termic
a geamului, şi alte două numere sunt importante pentru creșterea plantei productiv. Materialele pentru geamurile multe includ un
autocolant de Consiliul Naţional de evaluare a Fenestration, care listează următorii factori:
• SHGC sau energie termică solară obţine coeficientul este o măsură a cantității prezente de lumină solară care trece printr-un
geam de material. Un număr de 0,60 sau mai mare este de dorit.
• Factorul de u este o măsură de căldură care este pierdut în afara printr-un geam de material. Un număr mai mare sau egală cu
0.39 BTU/hr-ft2-F este de dorit.
• VT sau vizibil factor de transmisie se referă la cantitatea de lumină vizibilă care introduce printr-un geam de material. Un număr
de 0.70 sau mai mare este de dorit.
• PAR sau radiații photosynthetically activă este cantitatea de lumina soarelui în lungimi de undă critice pentru fotosinteză şi
creşterea plante sănătoase. Gama de lungime de undă PAR este între 400-700 Nano-metri (o măsură de lungime de undă).
Notă: Când alegerea geamuri, uita la transmisia vizual totală, nu PAR transmisia, pentru a vedea dacă materialul permite spectru
de lumină necesare pentru creșterea plantei sănătos.
În plus faţă de eficienţei energetice și transmisie a luminii, ar trebui să luaţi următoarele atunci când alegeţi materialele pentru
dumneavoastră cu efect de seră geamurile:
• Durată de viaţă
• Rezistenţă la deteriorări cauzate de grindină și pietre
• Abilitatea de a sprijini snowload
• Rezistenţă la condensare
• Foaie dimensiunea și distanța necesar între sprijină
• Rezistenţă la foc
• Ușor de instalat
(Bazat pe 6, 9, 10, 11, 12, 13, 14)
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Solare de stocare de căldură
Pentru serele solare pentru a rămâne cald în timpul nopţi rece sau zilele tulbure, căldura solară care introduce pe zile
insorite trebuie depozitate în seră pentru o utilizare ulterioară. Metoda cea mai comună pentru stocarea energiei
solare este să plasaţi roci, beton, sau apă în linie directă cu lumina soarelui să absoarbă sale de căldură.(1)
Cărămidă sau pereții umplute cu beton cinder bloc la partea din spate (partea de Nord) de seră poate oferi, de
asemenea, depozitare de căldură. Cu toate acestea, numai exterioară patru centimetri de grosime de acest material
de stocare efectiv absoarbe energie termică. Mediu şi întuneric colorate dale ceramice pardoseală poate oferi, de
asemenea, unele stocare de căldură.Pereţi (15) nu sunt utilizate de absorbție de energie termică trebuie lumina
colorate sau reflectorizant de căldură directe și lumina înapoi în seră și pentru a asigura o distribuție mai chiar a
luminii plantelor.
Materiale de stocare
Cantitatea de material de stocare de căldură necesare depinde de locaţia dumneavoastră. Dacă locuiţi în sudul sau
mid-latitude locuri, veţi avea nevoie de cel puțin 2 galoane de apă sau în 80 de livre de roci pentru a stoca căldura
transmisă prin fiecare pătrat picior de geam.(16) În cazul în care locuiţi în statele nordice, veti avea nevoie 5 galoane
42. sau mai mult de apă pentru a absorbi termic care intră prin fiecare pătrat picior de geam.(1) Aproximativ trei de
metri pătraţi de patru-inch gros cărămidă sau bloc cinder perete este necesar pentru fiecare pătrat picior de Sud-
confruntă sticlă.(15)
Cantitatea de material de căldură de stocare necesar, de asemenea, depinde dacă intenţionaţi să utilizaţi
dumneavoastră cu efect de seră solare pentru extinderea perioadei de vegetație, sau dacă doriţi să crească year-
round plante în el. Pentru sezonul extensie în rece climate, veti avea nevoie 2 ½ galoane de apă pe picior patrat
vitrajelor, sau aproximativ jumătate din ceea ce ar fi nevoie pentru producția tot parcursul anului.(2)
Dacă utilizaţi apă ca material de căldură de stocare, obişnuiţi galon 55 tobe pictat o culoare întuneric, reflectorizant
de lucru bine. Containere mai mici, cum ar fi lapte căni sau sticle din sticlă, sunt mult mai eficient decât galon 55
tobe în furnizarea de stocare de căldură în zone care sunt frecvent tulbure. Recipient mai mici are o proporţie mai
mare din suprafața care rezultă în mai rapidă absorbția căldurii, atunci când soarele straluceasca.(14) Din păcate,
recipientele din material plastic se degradează după două sau trei ani în lumina directă a soarelui. Recipiente de sticlă
clar oferi avantaje de capturare căldură mai bine decât întuneric recipientele din metal şi nu degradant, dar ele pot fi
uşor de spart.(17)
Trombe peretii sunt o metodă inovatoare pentru absorbția căldurii și depozitare. Acestea sunt scăzută pereţi plasat în
interiorul seră lângă Sud-confruntă windows. Ei absorbi energie termică pe partea din față (orientat spre sud) de
perete şi apoi radia acest căldură în seră prin partea de spate (orientate spre nord) de perete. Un perete de Trombe
constă într-un perete de 8-16 inch gros zidărie acoperit cu un material întunecat, absorbţiei de căldură şi cu care se
confruntă cu un singur sau dublu strat de sticlă plasate la 3/4 "6" departe de perete de zidărie pentru crearea unui
spațiu aerian mici. Termică solară trece prin sticlă și este absorbită de suprafață întunecată. Această energie termică
este stocată în perete, în cazul în care se efectuează încet perfecţionare activă prin intermediul zidărie. Dacă aplicaţi
o foaie de folie metalică sau alte suprafeței de reflexie pe suprafața exterioară a peretelui, aveţi posibilitatea să măriţi
termice solare absorbție de 30-60% (în funcţie de climă) în timp ce descrescătoare potențial de pierdere de căldură
prin pasivă radiații.(10, 18)
Trombe perete.
Foto: Australian Centrul pentru energie regenerabilă
