Solar-heet-greenhuouse

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Solar-heet-greenhuouse

  1. 1. Solar GreenhousesBarbara Bellows, updated by K. AdamNCAT Agriculture SpecialistsPublished 2008© NCATIP142Abstract Kans as CityThis resource list discusses basic principles of solar greenhouse design, as Cent erwell as different construction material options. Books, articles and Web forsites, and computer software relevant to solar greenhouse design are all Urba nprovided in a resource list. Agric ultur e.Table of Contents Phot o: NCA • Introduction T • Basic Principles of Solar Greenhouse Design • Solar Greenhouse Designs • Solar Heat Absorption • Solar Heat Storage • Insulation • Ventilation • Putting It All Together • References • Resources ○ Books ○ Articles, Fact Sheets, and Web Sites ○ Computer SoftwareIntroductionSince 2000, U.S. greenhouse growers have increasingly adopted high tunnels as the preferred solargreenhouse technology. Rigid frames and glazing are still common in parts of Europe, and in theclimate-controlled operations in Mexico and the Caribbean that produce acres of winter crops for NorthAmerican markets. (For more on climate-controlled technology, see Linda Calvin and Roberta Cook.
  2. 2. 2005. "Greenhouse tomatoes change the dynamics of the North American fresh tomato industry."AmberWaves. April. Vol. 3, No. 2.).All greenhouses collect solar energy. Solar greenhouses are designed not only to collect solar energyduring sunny days but also to store heat for use at night or during periods when it is cloudy. They caneither 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-efficientway for farmers to extend the growing season. In colder climates or in areas with long periods ofcloudy weather, solar heating may need to be supplemented with a gas or electric heating system toprotect plants against extreme cold. Active solar greenhouses use supplemental energy to move solarheated air or water from storage or collection areas to other regions of the greenhouse. Use of solarelectric (photovoltaic) heating systems for greenhouses is not cost-effective unless you are producinghigh-value crops.Hazards due to increased weather turbulence: • Hail • Tornados • High straight-line winds • Build-up of snow, iceThe majority of the books and articles about old-style solar greenhouses were published in the 1970sand 1980s. Since then, much of this material has gone out of print, and some of the publishers are nolonger in business. While contact information for companies and organizations listed in thesepublications is probably out of date, some of the technical information contained in them is stillrelevant.The newest form of solar greenhouse, widely adopted by U.S. producers, is high tunnels. The termglazing, 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-libraryloan 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 andarticles that specifically discuss "solar greenhouses." Since all greenhouses collect solar energy andneed to moderate temperature fluctuations for optimal plant growth, much of the information on"standard" greenhouse management is just as relevant to solar greenhouses. Likewise, muchinformation on passive solar heating for homes is also pertinent to passive solar heating forgreenhouses. As you look through books and articles on general greenhouse design and construction,
  3. 3. you will find information relevant to solar greenhouses in chapters or under topic headings thatdiscuss: • energy conservation • glazing materials • floor heating systems • insulation materials • ventilation methodsIn books or articles on passive solar heating in homes or other buildings, you can find usefulinformation 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 onsolar 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 CropsBack to topBasic Principles of Solar Greenhouse DesignSolar greenhouses differ from conventional greenhouses in the following four ways.(1) Solargreenhouses: • 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.
  4. 4. • 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 helpyou search for additional information, either on the "Web," within journals, or in books at bookstoresand libraries.Back to topSolar Greenhouse DesignsAttached 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. Thesestructures 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 typeand the hoophouse. A shed-type solar greenhouse is oriented to have its long axis running from east towest. 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 aconventional greenhouse, which has its roof running north-south to allow for uniform light distributionon all sides of the plants. To reduce the effects of poor light distribution in an east-west orientedgreenhouse, 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.
  5. 5. 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. 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 solargreenhouses, these do not have an insulated north side. Solarization of these structures involvespractices that enhance the absorption and distribution of the solar heat entering them. This typicallyinvolves the collection of solar heat in the soil beneath the floor, in a process called earth thermalstorage (ETS), as well as in other storage materials such as water or rocks. Insulation of thegreenhouse wall is important for minimizing heat loss. Heat absorption systems and insulationmethods are discussed in detail in the following sections.Back to topSolar Heat AbsorptionThe 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 usedSolar OrientationSince the suns energy is strongest on the southern side of a building, glazing for solar greenhousesshould ideally face true south. However, if trees, mountains, or other buildings block the path of thesun when the greenhouse is in a true south orientation, an orientation within 15° to 20° of true southwill provide about 90% of the solar capture of a true south orientation. The latitude of your locationand the location of potential obstructions may also require that you adjust the orientation of yourgreenhouse slightly from true south to obtain optimal solar energy gain.(2) Some growers recommendorienting the greenhouse somewhat to the southeast to get the best solar gain in the spring, especially
  6. 6. if the greenhouse is used primarily to grow transplants.(3) To determine the proper orientation forsolar buildings in your area, visit the sun chart program at the University of Oregon Solar RadiationMonitoring Laboratory Web page. You need to know your latitude, longitude, and time zone to use thisprogram. Solar path at 40° north latitude (2)Slope of Glazing MaterialIn addition to north-south orientation, greenhouse glazing should be properly sloped to absorb thegreatest amount of the suns heat. A good rule of thumb is to add 10° or 15° to the site latitude to getthe 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)GlazingGlazing materials used in solar greenhouses should allow the greatest amount of solar energy to enterinto the greenhouse while minimizing energy loss. In addition, good plant growth requires that glazingmaterials allow a natural spectrum of photosynthetically active radiation (PAR) to enter. Rough-surfaceglass, 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 bystructural supports causes more shadows and uneven plant growth. Diffuse light passing throughglazing 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 thedominant type of glazing used in greenhouses, with the weatherability of these materials beingenhanced by ultraviolet radiation degradation inhibitors, infrared radiation (IR) absorbency, anti-condensation drip surfaces, and unique radiation transmission properties.(7)
  7. 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 theair space between the two glazes will affect heat retention. Installation and framing for some glazingmaterials, such as acrylics, need to account for their expansion and contraction with hot and coldweather.(7) As a general rule, a solar greenhouse should have approximately 0.75 to 1.5 square feet ofglazing for each square foot of floor space.(1)Table 1. Glazing CharacteristicsGlass—single layer Factory sealed double glassLight transmission*: 85-90% Light transmission*: 70-75%R-value**: 0.9 R-value**: double layer 1.5-2.0, low-e 2.5Advantages: Advantages:• Lifespan indefinite if not broken • Lifespan indefinite if not broken• Tempered glass is stronger and requires • Can be used in areas with freezingfewer support bars temperaturesDisadvantages: 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 lightPolyethylene—single layer Polyethylene—double layerLight 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 1.7Advantages:• IR films have treatment to reduce heat loss Advantages:• No-drop films are treated to resist • Heat loss significantly reduced when acondensation blower is used to provide an air space between• Treatment with ethyl vinyl acetate results in the two layersresistance 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 inDisadvantages: 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 1-2years Disadvantages:• Light transmission decreases over time • Easily torn• Expand and sag in warm weather, then • Cannot see throughshrink in cold weather • UV-resistant polyethylene lasts only 1-2 years
  8. 8. • Light transmission decreases over time • Expand and sag in warm weather, then shrink in cold weatherPolyethylene—corrugated high density Laminated Acrylic/Polyester film—doubleLight transmission*: 70-75% layerR-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 polyesterDisadvantages: • Can last 10 years or moren/a Disadvantages: • Arcrylic glazings expand and contract considerably; framing needs to allow for this change in size • Not fire-resistantImpact modified acrylic—double layer Fiber reinforced plastic (FRP)Light transmission*: 85% Light transmission*: 85-90% - new material R-value**: single layer 0.83Advantages:• Not degraded or discolored by UV light Advantages:• High impact strength, good for locations • The translucent nature of this materialwith hail diffuses 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 yearsconsiderably; framing needs to allow for thischange 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 meltPolycarbonate—double wall rigid plastic Polycarbonate film—triple and quad wallLight transmission*: 83% rigid plasticR-value**: 6mm 1.6, 8mm 1.7 Light transmission*: 75% R-value** triple walls: 8mm 2.0-2.1, 16mmAdvantages: 2.5• Most fire-resistant of plastic glazing R-value** quad wall: 6mm 1.8, 8 mm 2.1materials• UV-resistant Advantages:• Very strong • Most fire-resistant of plastic glazing materials
  9. 9. • Lightweight • UV-resistant • Easy to cut and install • Very strong • Provides good performance for 7-10 years • Lightweight • Easy to cut and install Disadvantages: • Provides good performance for 7-10 years • Can be expensive • Not clear, translucent Disadvantages: • 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 efficiencyof the glazing, and the other two numbers are important for productive plant growth. Many glazing materials include a NationalFenestration 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. Anumber 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 lessis desired.• VT or visible transmittance refers to the amount of visible light that enters through a glazing material. A number of 0.70 orgreater is desired.• PAR or photosynthetically active radiation is the amount of sunlight in the wavelengths critical for photosynthesis andhealthy 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 allowsthe 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 foryour 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)Back to topSolar Heat Storage
  10. 10. For solar greenhouses to remain warm during cool nights or on cloudy days, solar heat that enters onsunny days must be stored within the greenhouse for later use. The most common method for storingsolar energy is to place rocks, concrete, or water in direct line with the sunlight to absorb its heat.(1)Brick or concrete-filled cinder block walls at the back (north side) of the greenhouse can also provideheat storage. However, only the outer four inches of thickness of this storage material effectivelyabsorbs 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 backinto the greenhouse and to provide a more even distribution of light for the plants.Storage MaterialsThe 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 heattransmitted through each square foot of glazing.(16) If you live in the northern states, you will need 5gallons 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 squarefoot of south-facing glass.(15)The amount of heat-storage material required also depends on whether you intend to use your solargreenhouse for extending the growing season, or whether you want to grow plants in it year-round. Forseason extension in cold climates, you will need 2 ½ gallons of water per square foot of glazing, orabout 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-reflectivecolor 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 ahigher 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 glasscontainers provide the advantages of capturing heat better than dark metal containers and notdegrading, but they can be easily broken.(17)Trombe walls are an innovative method for heat absorption and storage. These are low walls placedinside 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 ofthe 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 fromthe masonry wall to create a small airspace. Solar heat passes through the glass and is absorbed bythe dark surface. This heat is stored in the wall, where it is conducted slowly inward through themasonry. If you apply a sheet of metal foil or other reflective surface to the outer face of the wall, youcan increase solar heat absorption by 30-60% (depending on your climate) while decreasing thepotential for heat loss through outward radiation.(10, 18)
  11. 11. Trombe wall. Photo: Australian Center for Renewable EnergyWater walls are a variation of the Trombe wall. Instead of a masonry wall, water-filled containers areplaced in line with the suns rays between the glazing and the greenhouse working space. The watercan 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 feeton center. A one-foot spacer connects the two walls. Plastic-covered horse fence wire was thenfastened to each stud wall, and heavy-duty, dark-colored plastic water bags were inserted into thespace between the two walls. The stud walls were positioned vertically in line with the suns rays priorto the bags being filled with water.(19) Both the Solviva and Three Sisters Farm Web pages providedesigns 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 diameterto provide high surface area for heat absorption.(5) They can be piled in wire-mesh cages to keepthem contained. Since rocks have a much lower BTU storage value than water (35 BTU/sq.ft/°F forrocks versus 63 for water) (13), you will need three times the volume of rocks to provide the sameamount of heat storage. Rocks also have more resistance to air flow than water, resulting in lessefficient heat transfer.(20)Whichever material you choose to use for heat storage, it should be placed where it will collect andabsorb the most heat, while losing the least heat to the surrounding air. Do not place the thermal massso that it touches any exterior walls or glazing, since this will quickly draw the heat away.Phase-changeInstead of water or rocks for heat storage, you can use phase-change materials. While phase-changematerials are usually more expensive than conventional materials, they are 5 to 14 times moreeffective 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
  12. 12. • paraffin • Glaubers salt (sodium sulphate dcahydrate) • calcium chloride hexahydrate and • fatty acids (21, 22)They absorb and store heat when they change from solid to liquid phase, and then release this heatwhen they change back into a solid phase.(5) Calcium chloride hexahydrate has a heat storingcapacity 10 times that of water.(23) These materials are usually contained in sealed tubes, withseveral tubes required to provide sufficient heat storage. Because of the ability of phase-changematerials to absorb high quantities of heat, they also are useful in moderating greenhousetemperatures in the summer.Most of the research on the use of phase-change materials for greenhouses has been conducted inEurope, Israel, Japan, and Australia. In Israel, phase-change materials were incorporated intogreenhouse glazing, which increased heat capture and retention, but reduced the transparency of theglazing on cloudy days when the phase change material did not become liquid.(24) At the time ofpublication, two companies were identified—one in the U.S. and another in Australia—that sellunderfloor heating systems using phase-change materials.(25, 26) Phase-change drywall, currentlyunder research, incorporates phase-change materials inside common wallboard to increase its heatstorage capacity and could replace heavier, more expensive, conventional thermal masses used inpassive-solar space heating.(27) See the reference section for a listing of publications and Web sitesthat provide additional information about phase change materials.For more information, see the Phase Change Thermal Energy Storage Web site provides a detaileddiscussion of this technology.For many homeowners, building an attached solar greenhouse is very appealing. They believe that they can extend theirgardens growing season while reducing their home heating bills. Unfortunately, there is a contradiction between the use of agreenhouse 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 inlittle storage of heat for home use.• A home heat collector should be sealed to minimize the amount of heat loss. Greenhouses, however, require some ventilationto 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 butis an integral part of the living space. Bioshelters often integrate fish or small animals with vegetable production to completenutrient cycles. Biological control measures and plant diversity are used to manage pests in a way that is safe for people andpets 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 SolarAn 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
  13. 13. in the floor. If you use hot air for subsurface heating, inexpensive flexible drainage or sewage pipingabout 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 forgreater interaction between the heat in the tube and the ground. The surface area of the piping shouldbe equal to the surface area of the floor of the greenhouse. You can roughly calculate the number offeet of four-inch tubing you will need by dividing the square feet of greenhouse floor area by two. Onceinstalled, these pipes should be covered with a porous flooring material that allows for water to enterinto the soil around them, since moist soil conducts heat more effectively than dry soil. The systemworks by drawing hot air collected in the peak of the roof down through pipes and into the buriedtubing. The hot air in the tubes warms the soil during the day. At night, cool air from the greenhouse ispumped through the same tubing, causing the warm soil to heat this air, which then heats thegreenhouse.(29, 30) For more information on this design, see Solar Greenhouses for CommercialGrowers (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-topheating with root-zone thermal tubing is widely practiced in modern greenhouse production and canbe installed easily. A permanent floor heating system consists of a series of parallel PVC pipesembedded on 12" to 16" centers in porous concrete, gravel, or sand. Water is heated in an externalsolar water heater then pumped into the greenhouse and circulated through the pipes, warming thegreenhouse 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 forGreenhouse Crops.The Solviva greenhouse uses a variation of active solar heating. The system in this greenhouse relies onheat absorption by a coil of black polybutylene pipe set inside the peak of the greenhouse. The pipecoil lays on a black background and is exposed to the sun through the glazing. A pump moves waterfrom 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 asunny 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 greenhousestores heat better than an empty one. However, almost half of the solar energy is used to evaporatewater from leaf and soil surfaces and cannot be stored for future use.(5, 31) Solar heat can becomplemented 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 greenhouseatmosphere, coming from the decomposition activities of the microorganisms in the compost, canincrease the efficiency of plant production.While solar greenhouses can extend your growing season by providing relatively warm conditions, you should carefully selectthe 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:
  14. 14. 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)Back to topInsulationWall and Floor InsulationGood insulation helps to retain the solar energy absorbed by thermal mass materials. Keeping heat inrequires 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. Polyurethanefoams, polystyrene foams, and fiberglass batts are all good insulating materials. But these materialsneed to be kept dry to function effectively. A vapor barrier of heavy-duty polyethylene film placedbetween 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 isspecified for greenhouses in Illinois (1) and in Missouri (24), while R-21 is recommended for walls inNew Mexico.(10) The ZIP-Code Insulation Program Web site provides a free calculator for findingrecommended insulation R-values for houses based on your zip code.Richard Nelson of SOLAROOF developed an innovative way to insulate greenhouse walls in ahoophouse-style greenhouse. This system involves constructing a greenhouse with a double layer ofplastic sheeting as glazing. Bubble machines (such as are used to create bubbles at parties) areinstalled in the peak of the greenhouse between the two layers of plastic. At least two generatorsshould be installed, at either end of the greenhouse. During the winter, the bubble machines facenorth and blow bubbles into space between two sheets of plastic on the north side of the greenhouseto provide R-20 or higher insulation for northern winters. During the summer, the bubble machines canbe turned to face south to provide shading against high heat.(33)
  15. 15. Bubble greenhouse design.On greenhouse floors, brick, masonry, or flagstone serves as a good heat sink. However, they canquickly lose heat to the ground if there is not an insulating barrier between the flooring and the soil. Toprotect against heat loss, insulate footings and the foundation with 1- to 2-inch sheets of rigidinsulation or with a 4-inch-wide trench filled with pumice stone that extends to the bottom of thefootings. 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 InsulationYou also can insulate your greenhouse by burying part of the base in the ground or building it into theside of a south-facing hill.(5) Straw bales or similar insulating material also can be placed along theunglazed outside walls to reduce heat loss from the greenhouse.(34) Underground or bermedgreenhouses 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 anunderground greenhouse are wet conditions from the water table seeping through the soil on the floorand the entry of surface water through gaps in the walls at the ground level. To minimize the risk ofwater rising through the floor, build the underground greenhouse in an area where the bottom is atleast 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 wallswith waterproof material such as plastic or a fine clay. An excellent description of how to build a simplepit greenhouse is provided at the Web page for the Benson Institute, a division of the College of
  16. 16. Biology and Agriculture at Brigham Young University (BYU). This Institute has a campus in Boliviawhere students built an underground greenhouse based on local, traditional practices.(36) 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 heatloss. As mentioned previously, increasing the insulating value of glazing often decreases the amount ofsunlight entering the greenhouse. When selecting glazing for your greenhouse, look for materials thatprovide both good light transmission and insulating value. For example, polyethylene films referred toas "IR films" or "thermal films" have an additive that helps reduce heat loss.(37) Double or tripleglazing provides better insulation than single glazing. Some greenhouse growers apply an extra layerof glazing—usually a type of film—to the interior of their greenhouses in winter to provide an extradegree of insulation. Adding a single or double layer of polyethylene film over a glass house canreduce heat loss by as much as 50%.(38) By using two layers of polyethylene film in plastic-filmgreenhouses with a small fan blowing air between them to provide an insulating air layer, heat lossescan 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 andon cloudy days. By installing greenhouse insulation sheets made from two-inch thick bats ofpolystyrene, 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 polystyrenesheets at night and remove them in the morning. Magnetic clips or Velcro fasteners will facilitate theinstallation.(1) Alternatively, you can install thermal blankets made of polyethylene film, foam-backedfiberglass, or foil-faced polyethylene bubble material. These blankets are supported on wire tracks andcan be raised or lowered using pulleys. While greenhouse curtains composed of thermal blankets areusually opened and closed manually, a few manufactures have motorized roll-up systems that storethe blanket near the greenhouse peak.(5)
  17. 17. Solar greenhouse with solar curtains, water wall, and water heat storage on the north wall.(2)Back to topVentilationA building designed to collect heat when temperatures are cold also needs to be able to vent heatwhen temperatures are warm. Air exchange also is critical in providing plants with adequate levels ofcarbon dioxide and controlling humidity. Because of the concentrated air use by plants, greenhousesrequire approximately two air exchanges per minute (in contrast to the one-half air exchange perminute recommended for homes). To determine the flow requirements for your greenhouse, multiplythe volume of the greenhouse by two to get cubic feet of air exchange per minute, which is the rateused in determining the capacity of commercial evaporative coolers.Roof-ridge and sidewall vents provide natural ventilation. The sidewall vents allow cool air to flow intothe sides of the greenhouse, while ridge vents allow the rising hot air to escape. Some wind isnecessary for this type of ventilation system to function effectively. On still, windless days, fans arenecessary to move air through the greenhouse. The area of the venting should be equal to between1/5 to 1/6 of the greenhouse floor area.(1)
  18. 18. Solar chimneys arepassive solar collectorsattached to the highestpoint on the greenhouseand are combined withvents or openings oneither end of thegreenhouse. Thechimney has an inlet thatdraws warm air frominside the greenhouseand an outlet thatdischarges it to theoutdoors. To enhancesolar gain inside thechimney and increase A solar chimney. (2)airflow, the inner surfaceof the chimney stack is glazed or painted black. A ventilator turbine added to the top of the chimneyprovides 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 itwarm in winter. Since these materials absorb heat during the day, less heat radiates within thegreenhouse when the sun is shining. When the sun goes down, heat released from the thermal storagematerials can be vented out of the greenhouse.(2)Removing external shading can also decrease heat build-up within the greenhouse. Shading providedby mature trees is not recommended. Older books on solar greenhouse design (e.g., 2) argue thatdeciduous trees can provide shade in the summer but allow for plenty of sunlight to enter through theglazing 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 itsbranches, even when it has no leaves.(31)Active solar cooling systems include solar air-conditioning units and photovoltaics set up to runstandard evaporative cooling pads. Both are more complex and expensive to equip than passivesystems.Putting It All TogetherDesigning and building a solar greenhouse can be an exciting and rewarding project. Feel free to relyon 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 enhancethe efficiency of your structure. Several consulting companies can provide you with blueprints and
  19. 19. design assistance, often at a reasonable cost. See the Resources section for names and contactinformation for these companies. Of course, you need to weigh the costs of these new technologiesagainst the value of your greenhouse-grown crops. As you become familiar with the principles ofpassive solar design, you may want to experiment with ways of harnessing the power of the sun withinyour greenhouse to produce better plants throughout the year.Back to topReferences 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
  20. 20. 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]13. Smith, Shane. 2000. Greenhouse Gardeners Companion: Growing Food and Flowers in Your Greenhouse or Sunspace. Fulcrum Publishers. 2nd edition. 544 pages. Excerpts accessed at: www.greenhousegarden.com/energy.htm14. 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.html17. 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.html21. 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.htm23. Baird, Stuart, and Douglas Hayhoe. 1983. Passive Solar Energy. Energy Fact Sheet.
  21. 21. 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.html26. 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)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.htm29. 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.htm35. 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
  22. 22. 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 topResourcesKansas 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
  23. 23. Note: Many of the books listed below are out of print. You may be able to locate these books at apublic library or in a good used bookstore. Bibliofind is an excellent, searchable Web site where manyused and out-of-print books can be located.Solar GreenhousesAnon. 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.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 buildingseveral 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:SolvivaRFD 1 Box 582Vineyard Haven, MA 02568508-693-3341508-693-2228 FAXsolviva@vineyard.netEllwood, 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).
  24. 24. 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 thehouse solar greenhouses. Available for $18.95 from:Stackpole Books5067 Ritter Rd.Mechanicsburg, PA 17055800-732-3669Fontanetta, John. 1979. Passive Solar Dome Greenhouse Book. Storey Books.Pownal, VT. (Out of print).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-HeatedGreenhouses. 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. (Outof print).Magee, Tim. 1979. A Solar Greenhouse Guide for the Pacific Northwest.Ecotope, Seattle, WA. 91 p.Available for $6 from:Ecotope2812 E. MadisonSeattle, WA 98112206-322-3753Mazria, 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, butusually available from used booksellers.
  25. 25. Monk, G.J., D.H. Thomas, J.M. Molnar, and L.M. Staley. 1987. Solar Greenhouses for CommercialGrowers. Publication 1816. Agriculture Canada, Ottawa, Canada. 48 p.Nearing, Helen, and Scott Nearing. 1977. Building and Using Our Sun-Heated Greenhouse: GrowVegetables All Year-Round. Storey Books, Pownal, VT. 148 p. (Out of print).Shapiro, Andrew. 1985. The Homeowners Complete Handbook for Add-On Solar Greenhouses andSunspaces. 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. (Outof print).Stone, Greg. 1997. Building a Solar-Heated Pit Greenhouse. Storey Communications,Pownal, VT. 32 p. (Out of print).Strickler, Darryl J. 1983. Solarspaces : How (and Why) to Add a Greenhouse, Sunspace, or Solarium toYour 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 Startingand 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 developmentinformation. Ordering information available at: www.greenhouse.netThomas, Stephen G., John R. McBride, James E. Masker, and Keith Kemble. 1984. Solar Greenhousesand Sunspaces: Lessons Learned. National Center for Appropriate Technology. Butte, MT. 36 p. (Out ofprint).Williams, T. Jeff, Susan Lang, and Larry Hodgson. 1991. Greenhouses: Planning, Installing and UsingGreenhouses. Ortho Books, San Ramon, CA. 112 p.Yanda, William F. 1976. An Attached Solar Greenhouse. Lightning Tree Press, Boulder, CO. 18 p. (Outof 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 GreenhousesAldrich, Robert A., and John W. Bartok, Jr. 1989. Greenhouse Engineering. NRAES-33. CornellUniversity, Ithaca, NY. 203 p.
  26. 26. Provides a comprehensive treatment of the design and construction of medium- to large-scalegreenhouses, with over 60 tables and 100 diagrams. $30.Bartok, Jr., John W. 2001. Energy Conservation for Commercial Greenhouses. NRAES-3. CornellUniversity, Ithaca, NY. 84 p.Reviews the merits and limitations of current energy-conservation strategies for commercialgreenhouses. 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.Covers every aspect of designing and constructing a home greenhouse. Eight chapters discuss thefollowing topics: greenhouse basics, selecting a greenhouse, greenhouse planning, framing materialsand glazing, greenhouse layouts and equipment, the greenhouse environment, window greenhousesand growth chambers, and garden structures.The three books listed above are available from:Natural Resource, Agriculture, and Engineering Service (NREAS)152 Riley-Robb HallIthaca, New York 14853-5701607-255-7654607-254-8770 FAXNRAES@cornell.eduBond, 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 DesignAnderson, Bruce, and Malcolm Wells. 1981. Passive Solar Energy: The Home-owners Guide to NaturalHeating 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. Homeowners Guide to Energy Efficient and Passive Solar Homes. DIANEPublishing 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.
  27. 27. Levy, M. Emanuel, Deane Evans, and Cynthia Gardstein. 1983. The passive solar constructionhandbook: featuring hundreds of construction details and notes, materials specifications, and designrules of thumb. Rodale Press, Emmaus, PA. 328 p.Back to topArticles, Fact Sheets, and Web Sites • Solar Greenhouse Designs and Consultation • Greenhouse Glazing • Greenhouse Curtains • Solar Chimneys • Phase-Change Materials • General Greenhouse Information • Greenhouse Technical and Trade Publications • Solar Energy Organizations: National • Solar Energy Organizations: StateSolar Greenhouse Designs and ConsultationThe Bioshelter at Three Sisters FarmThe bioshelter includes a solar greenhouse, poultry housing, potting room, seed and tool storage, anequipment storage "barn," a kitchen for packing produce, compost bins, a reference library and livingspaces. A full report of the bioshelter design costs $8.00. Three Sisters Permaculture Design also offersconsultation on solar greenhouse design, construction and management.The Green GreenhouseAn 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 GreenhousesProvides design and construction consulting services for building solar greenhouses and homes.Specializes in subterranean solar heat systems.Hobby Greenhouse AssociationSells a Directory of Manufacturers: Hobby Greenhouses, Solariums, Sunrooms, and WindowGreenhouses for $2.50. Has links to many greenhouse manufacturers Web pages. A one-yearmembership to the association costs $15 and includes a subscription to Hobby Greenhouse, aquarterly magazine, and Hobby Greenhouse News, a quarterly newsletter.Hobby Greenhouse Association8 Glen Terrace
  28. 28. Bedford, MA 01730-2048781-275-0377Passive Solar GreenhouseProvides consulting services and passive solar greenhouse plans that have passed building codes forNew Mexico. Blueprints include lists of materials and where to purchase them.Solar Components CorporationSolar greenhouse kits as well as blueprints and materials for "build-your-own" solar greenhouses.Solar Components Corporation121 Valley StreetManchester, NH 03103603-668-8186Sundance SupplyProvides information on greenhouse design and installation. Sells materials needed for constructingand maintaining greenhouses.Sunglo Solar Greenhouses214 21st Street SEAuburn, WA 98002800-647-0606Free catalog of greenhouse kits available.Greenhouse GlazingGiacomelli, Gene A. 1999. Greenhouse coversing systems - User considerations. Greenhouse glazings:Alternatives under the sun. Cook College. Rutgers University.http://AESOP.RUTGERS.EDU/~ccea/publications.htmlGiacomelli, 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 EnergyUtilization in Horticultural Engineering. Acta horticulturae. Volume 257. p. 161-168. Orderinginformation at: www.actahort.org/books/257/index.htmMeyer, J. 1985. Greenhouse Construction and Covering Materials. ISHS Acta Horticulturae 170.Ordering information at: www.actahort.org/books/170/Efficient Windows CollaborativeNational Festration Council. 2002
  29. 29. Greenhouse CurtainsNational Greenhouse Manufactures Association. Helpful Hints: Internal and External GreenhouseCurtain Systems [PDF/125K]Agri-tech. Energy CurtainFAQs—Internal & External Greenhouse Curtain Systems. Griffin Greenhouse and Nursery SupplyNational Greenhouse Manufacturers AssociationSolar ChimneysAnon. 1986. Solar chimney for low-cost desert cooling. Popular Science. May. p. 16B-17C.Abrams, Don. 1984. The latest on solar chimneys. Rodales New Shelter. August. p. 10-11.Abrams, Donald W. 1986. Low-Energy Cooling: A Guide to the Practical Application of Passive Coolingand 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.) SolarizingYour 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 MaterialsVerner, Carl. 1997. Phase Change Thermal Energy Storage.http://freespace.virgin.net/m.eckert/carl_veners_dissertation.htmGeneral Greenhouse InformationAbraham, 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 Farms greenhouse guide. The New Farm. September-October. p. 32-36.
  30. 30. von Zabeltitz, Christian. 1990. Greenhouse construction in function of better climate control. ActaHorticulturae Vol. 263. p. 357-366Greenhouse Technical and Trade PublicationsActa HorticulturaeJournal of the International Society for Horticultural ScienceISHS SecretariatP.O. Box 5003001 Leuven 1, BelgiumGreenhouse GrowerMeister Publishing Company37733 Euclid Ave.Willoughby, OH 44094216-942-2000GM Pro (formerly Greenhouse Manager)Branch-Smith Publishing120 St. Louis Ave.Fort Worth, TX 76101800-433-5612817-882-4121 FAXwww.greenbeam.comNM Pro (formerly Nursery Manager)Branch-Smith Publishing120 St. Louis Ave.Fort Worth, TX 76101800-433-5612817-882-4121 FAXwww.greenbeam.comGrowerTalksBall Publishing335 N. River StreetPO Box 9Batavia, IL 60510-0009 USA630-208-9080630-208-9350 FAXGreenhouse Product NewsScranton Gillette Communications, Inc.
  31. 31. 380 E. Northwest Hwy.Des Plaines, IL 60016-2282708-290-6622Solar Energy Organizations: NationalAmerican Solar Energy Society2400 Central Ave., G-1Boulder, CO 80301303-443-3130Publishes Solar Today magazine and an annual membership directory; $70 annual membership fee.National Renewable Energy Laboratory. Energy Efficiency and Renewable Energy. U.S. Department ofEnergy. Passive Solar Heating, Cooling and Daylighting.www.eere.energy.gov/de/cs_passive_solar.htmlFact sheets include:Passive Solar Design for the HomeU.S. Department of Energy. Office of Building /Technology, State and Community Programs.Publications.Fact sheets include:Passive Solar DesignThe Solar Energy Research FacilityRenewable Energy Policy Project and Center for Renewable Energy and Sustainable TechnologyLinks 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: StateIllinois Solar Energy AssociationIndiana: Midwest Renewable Energy AssociationNew Mexico Solar Energy AssociationNorth Carolina Solar CenterOther sources of solar greenhouse factsheets have, in the past, included Oklahoma State CooperativeExtension Service, the Solar Energy Association of Oregon, the Texas State Energy Conservation
  32. 32. Office, and the Texas Solar Energy Society. The best way to find current information on suchorganizations is by doing a Web search.Back to topComputer SoftwareEREC. 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/Energy-10. A software package for solar energy design. Available from Solar Building IndustriesCouncil. www.sbicouncil.org/store/index.phpSUN_CHART™. A computer software that calculates and screen plots both cylindrical and polarsuncharts for any desired latitude. Available from:Optical Physics TechnologiesP.O. Box 11276Tucson, AZ 85734Acknowledgements: ATTRA agricultural specialists Janet Bachmann, Mike Morris, and Steve Diverprovided excellent reviews of this document. Steves many files on solar greenhouses were extremelyuseful in identifying the breadth of solar greenhouse designs.Solar GreenhousesBy Barbara Bellows, updated by K. AdamNCAT Agriculture SpecialistsMary Ann Thom, HTML Production© NCATIP142Back to topThis page was last updated on: February 25, 2011Serele solareBarbara Bellows, actualizate de către K. AdamSpecialişti în agricultură NCATPublicat 2008© NCATIP142
  33. 33. AbstractAceastă listă de resursă discută despre principiile de bază ale proiectaresolare cu efect de seră, precum şi opţiuni diferite de construcție demateriale. Cărţi, articole şi site-uri Web şi programe de calculatorrelevante pentru proiectare de seră solare sunt furnizate într-o listă de Kansresursă. as City Cent erCuprins pentr u • Introducerea agric ultur • Principiile de bază ale solare cu efect de seră Design ă urba ne. • Solare cu efect de seră Designs Foto: NCA • Solare de absorbție de energie termică T • Solare de stocare de căldură • Izolare • Ventilație • Pune-O împreună • Referinţe • Resurse ○ Cărţi ○ Articole, fișele şi site-uri Web ○ Programe de calculatorIntroducereaÎncepând cu 2000, U.S. cu efect de seră cultivatorilor au din ce în ce adoptat tuneluri de mare catehnologie cu efect de seră solare preferată. Rame rigide și geamurile sunt încă comune în regiuni aleEuropei și controlate de clima operaţiunile în Mexic şi Caraibe care produc de acri de culturilor de iarnăpentru piețele din America de Nord. (Pentru mai multe pe tehnologia de climat controlat, consultaţiLinda Calvin și Roberta Cook. 2005. "Tomate de seră Schimbarea dinamica a industriei din America deNord de tomate proaspete." AmberWaves. Aprilie. Vol. 3, nr. 2.).Toate sere colecta energia solară. Serele solare sunt concepute pentru a colecta energia solară întimpul zile insorite dar, de asemenea, pentru a stoca energie termică pentru folosirea pe timp denoapte sau în timpul perioadelor când este tulbure. Acestea fie poate sta singur sau se anexează case
  34. 34. 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 primulrând 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 cuperioade lungi de vreme tulbure, încălzire solare pot trebuie să fie completate cu un gaz sau un sistemde încălzire electrică necesară protejarea plantelor împotriva frigului. Serele solare activă utilizaţisuplimentare de energie pentru a muta solare de aer încălzit sau apă din zonele de depozitare saucolectarea alte regiuni de seră. Utilizarea solare electrice (fotovoltaice) sisteme pentru serele deîncălzire 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, gheaţăMajoritate de cărţi şi articole despre sere solare stil vechi au fost publicate în anii 1970 și 1980. Deatunci, mare parte din acest material a plecat din imprimare şi unele dintre editorii nu mai sunt înafaceri. În timp ce informaţii de contact pentru companii si organizatii enumerate în aceste publicaţiieste 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 detuneluri. Termenul pentru geamurile, astfel cum este utilizat în prezenta publicație, include trimitere laÎmbrăcămințile de polietilenă pentru caselor cercui.Adesea publicaţii afară de imprimare poate fi găsit în librăriile utilizate, biblioteci, şi prin programul deinter-library de împrumut. Unele publicaţii sunt de asemenea disponibile pe Internet. Bibliofind este unexcelent, 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 decercetare de cărţi şi articole care în mod specific discuta "solare sere." Deoarece toate sere colectaenergia solară și necesitatea de a moderată fluctuațiilor de temperatură pentru creșterea planteioptimă, mult de informații asupra gestionării de seră "standard" este doar de relevante pentru seresolare. De asemenea, mai multe informaţii despre pasivă solare încălzire pentru casele este deasemenea pertinente pentru încălzire solare pasive pentru sere. Aşa cum te uiţi prin cărţi şi articoledespre generale cu efect de seră proiectarea și construcția, veţi găsi informaţii relevante pentru seresolare în capitolele sau sub titlurile de subiect care discuta: • conservarea energiei • materialele pentru sticla • sisteme de încălzire podea
  35. 35. • materiale izolante • metode de ventilațieÎn cărți sau articole pe pasivă solare încălzire în casele sau alte clădiri, puteţi găsi informaţii utile pesere solare prin căutarea de capitole sau titlurile de subiect care examinează: • orientarea solare • 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 concentreazăîn 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 serăBack to topPrincipiile de bază ale solare cu efect de seră DesignSerele 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 şiîntreţinerea o structură eficiente energetic. De asemenea, puteţi utiliza aceste concepte care vă ajutăsă căutaţi informaţii suplimentare, fie de pe "Web," în jurnale sau în cărţi la librăriile şi biblioteci.Back to top
  36. 36. Solare cu efect de seră DesignsAtaşat 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 structuride obicei au un design pasivă solare.Tancuri serele solare sunt suficient de mare pentru producția comercială de culturi, legume sau plantearomatice. Există două primar desene sau modele pentru serele solare tancuri: tipul de magazie șihoophouse. Un tip de magazie solare seră este orientată spre are axa lungă să fie difuzate de la est lavest. Peretele de Sud-confruntă este lustruit să colecteze valoarea optimă a energiei solare, în timp cewall nord-cu care se confruntă este well-insulated pentru a preveni pierderea de căldură. Aceastăorientare este în contrast cu o seră convenţionale, care are său acoperiş execută Nord-Sud pentru apermite distribuția luminii uniforme pe toate laturile de plante. Pentru a reduce efectele săracidistribuția luminii într-o seră orientate spre est-vest, peretele nord este acoperit sau pictat cureflectorizant.(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.
  37. 37. 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 îmbunătăţescabsorbție și distribuție a energiei termice solare introducerea ei. Acest lucru implică de obicei colecţiede căldură solare în sol sub podea, într-un proces numit pământ termice stocare (ETS), precum și înalte materiale de stocare, cum ar fi apă sau roci dislocate. Izolare a peretelui cu efect de seră esteimportant pentru minimizarea pierderii de căldură. Sisteme de absorbție de căldură și metodele deizolare sunt discutate în detaliu în următoarele secţiuni.Back to topSolare de absorbție de energie termicăDoi factori cele mai critice care afectează cantitatea de căldură solare o seră este capabil să absoarbăsunt: • Poziţia sau locaţia cu efect de seră în raport cu soarele • Tipul de geam materialul utilizatOrientarea solareDeoarece energie de la soare este mai puternică pe latura de Sud a unei clădiri, geamuri pentru serelesolare ideal ar trebui să se confruntă Sud adevărat. Cu toate acestea, în cazul în care copaci, Munţiisau alte clădiri bloca calea soarelui atunci când seră este într-o orientare Sud adevărat, o orientare întermen de 15 ° la 20 ° de Sud adevărat va oferi aproximativ 90% din captură solare de o orientare Sudadevărat. Latitudine de locaţia și locația potenţiale obstacole pot solicita, de asemenea, că vă ajustaorientarea dumneavoastră cu efect de seră uşor la south adevărat pentru a obţine câştig optimă deenergie solară.(2) Cultivatorii de unele recomanda orientare de seră oarecum la sud-est pentru aobţine cel mai bun câştig solare în primăvara, mai ales dacă seră este utilizată în principal să creascătransplanturi.(3) Pentru a determina orientarea corectă pentru clădiri solare în zona dumneavoastră,vizitează programul de diagramă soare la laboratorul de monitorizare Universitatea din Oregon solareradiații pagina Web. Trebuie să ştiţi dumneavoastră latitudine, longitudine şi fusul orar pentru a utilizaacest program.
  38. 38. Calea solare la 40 ° latitudine nordică (2)Panta Material pentru geamurileÎn plus faţă de orientare nord-sud, cu efect de seră geamuri trebuie să fie corect înclinat să absoarbăcea 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 sauIllinois centrală la 40 ° Nord latitudine, geamul trebuie să fie înclinat la unui 50 ° de unghiul de 55 ° (40° + 10 ° sau 15 °).(4)GeamuriMaterialele folosite în sere solare geamurile ar trebui să permită cea mai mare cantitate de energiesolară să intre în de seră, în timp ce minimizarea pierderii de energie. În plus, creșterea plantei bunpresupune că materialele pentru geamurile permite un spectru naturale de radiaţii photosyntheticallyactivă (PAR) pentru a intra. Stare brută-suprafață sticlă, dublu strat rigide din material plastic şifiberglass lumină difuză, în timp ce clar sticlă transmite lumina directă. Deşi plantele cresc bine culumină directă şi difuze, lumină direct prin geamurile subdivizate după sprijină structurale cauze maimulte umbre şi creșterii plantelor inegala. Lumină difuză care trece prin geamurile evens afară umbrecauzate 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. Materialeplastice acum sunt dominante tip de geam utilizate în sere, cu weatherability aceste materiale fiindîmbunătăţită prin radiaţii ultraviolete degradare inhibitori, radiații infraroşu (IR) de atenuare așocurilor, picurare anti-condensation suprafețelor și radiația unic transmiterea proprietăţi.(7)Metoda utilizată pentru montarea material geamurile afectează suma de pierdere a căldurii.(8), Deexemplu, crăpături sau găuri cauzate de montare va permite căldură să scape, în timp ce diferențele
  39. 39. de lățimea spațiului aerian între două smalțuri va afecta retenţie de căldură. Instalare şi schelet pentruanumite materiale de geamuri, cum ar fi acrylics, trebuie să țină seama de extinderea și contracția cucald si rece vremea lor.(7) Ca regulă generală, o seră solare ar trebui să aibă de aproximativ 0,75 la1,5 metri pătraţi de geamuri pentru fiecare pătrat picior de podea spaţiu.(1)Tabelul 1. Caracteristicile de geamuriSticlă — singur strat Fabrică sigilate sticlă dublăLumina transmiterea *: 85-90% Lumina transmiterea *: 70-75%Bolizi **: 0.9 Bolizi **: dublu strat 1.5-2.0, low-e 2.5Avantajele: Avantajele:• Durată nedeterminată dacă nu rupt • Durată nedeterminată dacă nu rupt• Temperat sticlă este mai puternic şi • Pot fi utilizate în zonele cu temperaturilor denecesită mai puţine suport baruri înghețDezavantaje: Dezavantaje:• Fragile, uşor rupt • Grele• Nu poate rezista la greutatea de zăpadă • Clar sticlă difuze lumină• Necesită numeroase sprijină • Dificil pentru a instala, necesită definirea• Clar sticlă difuze lumină precisăPolietilenă — singur strat Polietilenă — strat dubluLumina transmiterea *: 80-90%-material Lumina transmiterea *: 60-80%nou Bolizi ** dublu filme: 5 ml filmul 1.5, 6 mlBolizi **: singur filmul 0.87 filmul 1.7Avantajele: Avantajele:• IR filme au tratament pentru a reduce • Pierderea de căldură redusă semnificativ atuncipierderea de căldură când se utilizează un ventilator pentru a oferi un• Nu picătură filme sunt tratate pentru a spaţiu aerian între două straturirezista condensare • IR filme au tratament pentru a reduce pierderea• Tratament cu acetat de vinil etil rezultate de căldurăîn rezistența la cracare la rece şi de rupere • Nu picătură filme sunt tratate pentru a rezista• Uşor de instalat, precise nu judicioase condensarenecesare • 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 necesareDezavantaje: • Cel mai mic cost material de geamuri• Uşor rupt• Nu poate vedea prin Dezavantaje:• Polietilenă rezistentă la UV dureaza numai • Uşor rupt1-2 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 animicşora în vreme rece • Scade de transmisie a luminii în timp
  40. 40. • Extinderea şi sag în vremea calda, apoi micşora în vreme recePolietilenă — cartonului ondulat Stratificată acrilic/poliester filmul — stratdensitate mare dubluLumina 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 multDezavantaje:n/a Dezavantaje: • Arcrylic sticlă extinde şi contract considerabil; încadrare are nevoie pentru a permite această schimbare în mărimea • Nu rezistente la focImpactul modificate acrilic — strat dublu Fibra întărite de plastic (FRP)Lumina transmiterea *: 85% Lumina transmiterea *: 85-90%-material nou Bolizi **: singur strat 0.83Avantajele:• Nu degradate sau decolorate în lumină UV Avantajele:• Forţa de impact ridicat, bun pentru locaţii • Natura translucide acest material diffuses şicu grindină distribuie uniform lumină • Tratate de Tedlar panouri sunt rezistente laDezavantaje: vremea, lumina soarelui şi acizi• Arcrylic sticlă extinde şi contract • Puteţi ultimii 5-20 aniconsiderabil; încadrare are nevoie pentru apermite 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 topiPolicarbonat — dublu perete rigide din Policarbonat filmul — triplu şi quad peretematerial plastic rigide din material plasticLumina 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 2.1Avantajele:• Cele mai rezistente la foc de plastic Avantajele:materialele vitrajelor • Cele mai rezistente la foc de plastic materialele• Rezistentă la UV vitrajelor
  41. 41. • 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)Aveţi nevoie pentru a înţelege patru numere în selectarea geamuri pentru serele solare. Două numere descrie randamentultermic a geamului, şi alte două numere sunt importante pentru creșterea plantei productiv. Materialele pentru geamurile multeinclud 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-ungeam 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 cu0.39 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. Unnumăr 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 şicreşterea 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 permitespectru 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 pentrudumneavoastră 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)Back to topSolare de stocare de căldurăPentru serele solare pentru a rămâne cald în timpul nopţi rece sau zilele tulbure, căldura solară careintroduce pe zile insorite trebuie depozitate în seră pentru o utilizare ulterioară. Metoda cea mai

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