Efficient Agricultural Buildings: An Overview


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Efficient Agricultural Buildings: An Overview

  1. 1. Efficient Agricultural Buildings: An Overview FARM ENERGY SYSTEMS GUIDE Abstract: Efficiency-focused building designs reduce the use of materials and energy in building construction and operation. Planning for efficiency can help save money and improve building performance. This publication discusses several ways to improve the efficiency of agricultural buildings and provides further references for implementing those strategies. Topics covered include suiting a building to its site, using natural systems, using renewable energy, conserving energy, and conserving material resources in construction.By Tracy MummaNCAT Agricultural Energy SpecialistNovember 2002 Introduction Efficient buildings can save money and im- Table of Contents prove comfort while reducing resource consump- tion. Designers and builders nationwide are cre- ating new buildings that save energy and water, Introduction ......................................... 1 use fewer material resources, and create less Matching Building to Site .................... 2 waste. Through the U.S. Green Building Using Natural Systems ....................... 3 Council’s LEED rating system (1), the federal Energy Star® certification (2), and green build- Renewable Energy for ing programs in states and communities, the Agricultural Buildings ..................... 5 building industry is developing standards that help measure and compare building efficiency. Energy Conservation in Several awards programs recognize green build- Agricultural Buildings ..................... 6 ings, and professional organizations provide Resource Conservation in Agricultural training for designing and constructing more ef- ficient buildings (3). From architects to contrac- Building Construction ..................... 8 tors to owners, more people are recognizing the Other Efficiency Strategies for benefits of efficient building and implementing Agricultural Buildings ........................ 12 efficiency strategies in their building projects. You don’t have to participate in any special pro- Summary ........................................... 12 gram to practice and enjoy the benefits of effi- References ........................................ 13 cient building. Farmers and ranchers can join in Further Resources ............................ 14 the savings by incorporating efficiency in their plans for new buildings or renovations. Whether Web-based Resources ..................... 14 you are planning housing, barns, equipment sheds, greenhouses, storage spaces, or even spe- cialized facilities for agritourism or product pro- cessing, efficiency is an important consideration.ATTRA is the national sustainable agriculture information service operated by the National Centerfor Appropriate Technology under a grant from the Rural Business-Cooperative Service, U.S.Department of Agriculture. These organizations do not recommend or endorse products,companies, or individuals. ATTRA is headquartered in Fayetteville, Arkansas (P.O. Box 3657,Fayetteville, AR 72702), with offices in Butte, Montana, and Davis, California.
  2. 2. One of the challenges of efficient building is cases, this may require a sophisticated blendingthat there is no single solution that applies in ev- of local design wisdom with state-of-the art tech-ery instance. Depending on where a building is nology.located, what its purpose is, and how long it will One of the first steps in building construc-be needed, the most efficient design and materi- tion is site selection. Savvy designers recom-als for a particular situation may be very differ- mend careful study of potential sites, to identifyent from the best options for other circumstances. how they are affected seasonally by water, wind,An unheated storage and sun (5). Mapping orbuilding, a large barn, recording the incidenceand a home all have of these forces over the Efficient building principlesdifferent require- course of a year can helpments for comfort, identify the best site for a • Minimize operating energy.function, and effi- building on a particular • Incorporate renewable energy whereverciency. In general, the piece of property. An- possible.most efficient building other important consid- • Optimize material use with the fewest,is one that is respon- eration for building is the best materials.sive to its local cli- substrate of the site. • Design for local conditions; build withmate, efficiently con- Some soil conditions local materials.structed of locally ob- make construction so ex- • Conserve resources in design,tained materials, and pensive as to be imprac- construction, and operation.requires minimal en- tical, while just a slightergy to operate and change in terrain canmaintain. This publi- mark a completely differ-cation discusses some of the strategies for effi- ent—and more suitable—soil type. Building oncient building, such as using natural systems for less-stable soil is often possible with speciallybuilding comfort, using renewable energy in ag- designed foundations, but the difficulty of suchricultural buildings, and conserving energy, ma- construction can add significantly to the cost. It’sterials, and water. Sources of detailed informa- best to seek a stable, well-drained soil that cantion are provided in the Further Resources sec- support some type of standard foundation,tion. whether that be pier, slab on grade, conventional poured footings, or a frost-protected shallow foundation. Once you identify a building site, it’s time to Matching Building review your priorities for the building itself, to to Site come up with the most efficient design for the location and situation. • How big does the building need to be? • How can the design work with the features In many parts of the country, buildings that of the site?predate the era of central heating and cooling of- • Does the building need to be permanent, orten employ locally developed adaptations to cli- will a temporary structure suit the purpose?mate. For example, buildings in extremely • Does the building need supplemental heat-snowy regions are characterized by steep roofs, ing and cooling, or can natural processeslong roof overhangs, and tight construction. In maintain comfort?hot climates, shading and ventilation are impor- • What materials are available locally?tant design considerations (4). This vernaculararchitecture—designs and details developed fora specific local climate—has become rarer as rela- Related ATTRA Publicationstively inexpensive energy and sophisticated tech- • Learning More about Wind-powerednologies have made it possible to create artifi- Electric Systems for Homes, Farms, andcial indoor climates. Yet climate creation comes Ranchesat a high cost. The most efficient and least costly • Anaerobic Digestion of Animal Wasteslong-term solution is to design a building that is • Organic Alternatives to Treated Lumberresponsive to the location it will occupy. In somePAGE 2 //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW
  3. 3. The interior light gained from windows can be increased by beveling the window opening Using Natural Systems to allow more light to enter the room. This is particularly true for structures with thick walls, where incoming light can otherwise be severely The more energy a building can capture pas- limited by the depth of the opening.sively from natural forces, the less the owner has For buildings without windows, for interiorto pay to operate it. In temperate climates there rooms, or for spaces in the middle of large openmay be little challenge in keeping a building com- buildings, a skylight may offer the bestfortable for people or animals without supple- daylighting option. There are several alternativesmentary energy, but in more extreme climates it available, ranging from fixed or operable clear-takes careful planning to put nature’s energy to glass skylights to diffused-tube skylights to trans-work heating or cooling your building. Fortu- lucent roofing material. Translucent roofing is anately, the savings potential is usually well worth realistic option only in the relatively few areasthe extra effort. where roof insulation isn’t of greater value than the amount of light gained, such as in very tem- DAYLIGHTING perate climates or in unheated buildings. Mean- while, clear-glass skylights may actually provide Daylighting involves direct use of the sun to too much lighting in some situations. Glare andlight the inside of a building. It may provide the overheating of the area directly below the sky-sole light for a building that is used infrequently light can be problems. Operable skylights canor only during the day. It can also be used in a be valuable tools for ventilation as well as light-self-adjusting or manually adjusted system that ing, but they are expensive and can cause watermaintains a steady level of light by supplement- damage if improperly installed.ing with artificial light when daylight is insuffi- In situations where a lot of light is needed,cient. or where light must penetrate deep into a build- Windows are the most familiar way to let in ing, exterior appliances such as light shelves ordaylight. In many climates, however, inefficient reflectors can be applied to boost daylight’s reach.windows lose more heating and cooling energy This type of equipment can not only multiply thethan they gain in lighting energy (6). Conse- effect of daylighting, it can also improve the qual-quently, it’s important to ity of the light by diffus-budget for the most effi- ing and redirecting it.cient windows possible Such appliances can helpand to place them where to improve the energy con-natural light is most tribution of windows, inneeded and energy loss is situations where theheld to a minimum. added investment is justi-Looking at sun-angle fied (7).charts for a particular lati- For information ontude and season can help daylighting and examplesidentify the optimum as- of its application, see thepect and height for win- Further Resources section.dow placement. (For verydetailed information on NATURALsolar calculation, see the VENTILATIONSolar Position and Inten-sity calculator available Operable windowsfrom the National Renew- and/or skylights can aidable Energy Laboratory at in ventilation and provide<http://rredc. nrel.gov/ cooling, especially in cli-solar/codes_algs/ mates where the day andsolpos/> or consult the night temperatures differpassive-solar design soft- significantly. Land formsware cited below.) and vegetation can also //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW PAGE 3
  4. 4. help to channel breezes for increased ventilation the heat from the summer sun high in the sky.efficiency. In warmer areas, these simple mea- The optimal height of windows from the groundsures may need to be augmented to provide ad- and the size of overhang needed to shade themequate cooling. from the summer sun can be calculated for dif- One means of providing greater cooling for ferent latitudes in the United States by using sun-a building than simply opening the windows is angle tables or software (see the Further Re-a cooling tower that vents hot air out the top of sources section). The right amount of windowthe building and pulls in cooler air from the low- area and the correct configuration of shading canest level of the structure. The concept is gener- make the difference between a comfortable natu-ally familiar to farmers, many of whom have seen rally-heated building and a space that feels likeit at work in barn cupolas. For greatest efficiency an oven.the upper-level vents should be operable, to pre- In a structure with passive solar heat, cap-vent undesirable heat loss in winter, and incom- turing heat from the sun is only part of the battle.ing air should be drawn from the lowest level Storing it to help moderate night-time tempera-through a “stack” design (8). In some desert cli- ture swings is also a key element in a passivemates, the effectiveness of cooling towers is in- solar design. Storage capacity is provided bycreased by drawing incoming cool air over a pool thermal mass within the structure. There areor tank of water, to add evaporative cooling. In- many options for providing thermal mass, rang-troducing moisture to the incoming air can help ing from special interior walls containing barrelsaid cooling in arid areas, although it doesn’t work of water to dark-colored stone flooring. Whenat all in humid climates. energy-efficient windows are used in conjunc- Another idea that can be adapted from desert tion with a thermally efficient and well-sealedarchitecture is the wind catcher. These air col- building envelope, however, the mass of ordi-lectors face into the prevailing wind, and funnel nary flooring and interior walls may be enoughmoving air into occupied spaces to provide a to modulate building temperature and help pro-cooling breeze (9). The effectiveness of a wind vide for occupant comfort. In northern climatescatcher obviously depends on available air cur- it is critical to include night insulation measuresrents. The Further Resources section lists sources for windows in passive solar designs. Otherwise,of information on natural ventilation strategies. in climates with over 6000 heating degree days— the cumulative number of degrees in a year by PASSIVE SOLAR which the mean temperature falls below 65°F.— windows that are supposed to provide heat gain In many locations the sun is the cheapest and can actually cause a net heat loss. (Maps show-most reliable heat source. By siting and design- ing heating degree days and cooling degree daysing a building for the best capture of solar gain, for the United States are available from The Na-the owner can reap maximum energy gain from tional Climatic Data Center, viewable online ata minimal investment. <http://lwf.ncdc.noaa.gov/oa/documentli The best orientation for passive solar perfor- brary/clim81supp3/clim81.html>.)mance places the long axis of a building within There are many good references on passive20 degrees of perpendicular to true south. This solar design details, some of which are listed inprovides a building with solar gain from its the Further Resources section at the end of thissouthern exposure, while reducing the potential publication. There are also many experiencedfor overheating that comes from greater western solar design professionals who can be of service.exposure. For best passive solar performance, the high- SHADINGest concentration of windows should be on thebuilding’s southern face, although generally the Often in agricultural buildings there is lesstotal window area should not exceed 15% of the concern with capturing enough solar heat thanbuilding’s total floor area. Southern windows with preventing overheating. In warm climatesprovide the best opportunity for solar heat gain and seasonally used buildings, preventing heatin winter. Through careful placement and shad- gain may be the more important strategy, anding, these windows can capture the heat from a shading is a key means of avoiding unwantedlow-angle winter sun, while excluding much of heat buildup.PAGE 4 //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW
  5. 5. Shade can be provided by vegetation, con-structions, or a combination of the two. Quick-growing deciduous trees are often chosen be- Renewable Energy forcause they can provide summer shade for a struc-ture, yet when their leaves have fallen they al- Agricultural Buildingslow the sun to reach the building and boost so-lar gain during the winter. Trellises can also pro-vide window shading, especially when coveredwith vines or other vegetation during the grow- PHOTOVOLTAICSing season. Awnings and slatted above-window Solar electric energy systems, or photovolta-shades are other means of protecting windows ics, can supply power for any number of remotefrom heat gain during the months when the sun agricultural applications, including pumping andis high in the sky. Information on shading strat- electric fencing. See the related ATTRA publica-egies is included in the Further Resources sec- tions Solar-powered Livestock Watering Systems andtion. Freeze Protection for Solar-powered Livestock Water- ing Systems. Photovoltaics can also be used to EARTH BERMS generate electricity for lighting buildings or op- Another natural force that can significantly erating equipment and appliances. There are sev-contribute to reducing energy use in buildings is eral options for solar electric systems. They canthe temperature-moderating thermal mass of the be designed to tie into the power grid as utilitiesearth itself. When a building is set into a slope allow, feeding any excess power back into theor simply set deeper than usual into the ground grid to run the meter backwards, and drawingof a level site, the surrounding earth helps shel- power from the grid when they aren’t generat-ter the structure from heat loss or gain. The sur- ing. At remote sites, photovoltaics team withrounding earth acts as a thermal reservoir, mod- storage batteries to provide a reliable power sup-erating the indoor temperature of the building ply at any time. The solar panels can be mountedas the outside air temperature changes. There on a building rooftop that provides the right as-are two important considerations when earth- pect and angle, or mounted in a freestanding ar-berming buildings: the structure must be de- ray.signed to support the pressure of the surround- One recent development in solar panel tech-ing earth, and the building system must be pro- nology may be especially relevant to agriculturaltected from moisture in the soil. It is also worth buildings. Manufacturers are now offering sev-checking the average annual ground temperature eral roofing products that combine roofing ma-of the building site, to assess whether the differ- terial and photovoltaic electricity-generating ca-ence between air and soil temperature provides pacity in a single unit. Both slate-styleand stand-a bermed building with a significant thermal ad- ing-seam-style panels are available from Uni-vantage. Solar products <http://www.uni-solar.com/ bipv _resid.html>. Although these products are expensive, they can be economical for new roofs //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW PAGE 5
  6. 6. at sites that are far from the power grid. When be particularly well-suited to rural sites. Small-the cost of roofing and the cost of power genera- scale wind power, biomass generation, micro-tion are both weighed in the balance, building- hydro power, and methane digesters are all po-integrated photovoltaics (BIPV) can come out the tential sources of renewable power for agricul-winner for some locations (10). tural buildings. More information is available in the ATTRA publications Learning More about SOLAR HOT WATER Wind-powered Electric Systems for Homes, Farms, and Ranches and Anaerobic Digestion of Animal Solar water-heating systems range from the Wastes.simple and homemade to the complex and ex-pensive. Generally they serve to preheat waterbefore it reaches a conventional water heater,minimizing the energy that the water heater then Energy Conservation inuses to boost the water to its final temperature.In some climates and seasons, the solar water Agricultural Buildingsheater may bring the water to full temperaturewithout supplementary heating. The use of mostsolar water-heating systems is seasonal in cold Before investing in renewable energy genera-climates, where systems must be drained dur- tion systems for any building, it pays to makeing winter to prevent water in the system from sure that the building is as energy efficient asfreezing. More complex systems that heat an possible. Improving energy efficiency is gener-anti-freeze liquid and then transfer that heat to ally a minimal investment compared to the ex-water inside a heated space can be used through- pense of solar panels or a wind generator. Theout the year (11). For seasonally occupied or level of energy efficiency appropriate for a givenwarm-climate agricultural buildings, even a building differs according to its use characteris-simple solar hot-water system can offer energy tics. If a building is rarely occupied or heated,savings at minimal cost. See the Further Re- energy efficiency investments won’t be as costsources section for additional sources of infor- effective. For occupied buildings, however, themation. payback time for most investments in energy ef-OTHER RENEWABLE POWER SOURCES FOR ficiency is relatively short, making conservation measures an easy choice for building owners (12). BUILDINGS In addition to the sun, many other renewable INSULATIONpower sources exist, and a number of them may Insulation is the first line of defense for heated or cooled buildings. Insulation increases the re- sistance of the building to heat flow, helping to keep heated or cooled air from es- caping. Insulation also pro- vides sound-deadening properties. Today the most common types of building insulation are fiberglass, cel- lulose, or petroleum-based foam, though many specialty types of insulation are com- mercially available, includ- ing cementitious foam, straw, and mineral fiber. Historically, a wide range of materials, including cattle hair and shaved wood fiber,PAGE 6 //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW
  7. 7. were used for insulation. Important concerns for most cases a double-pane window with low-eany insulation material are that it be fire and in- coating will provide adequate energy perfor-sect resistant, as well as thermally efficient. La- mance. The energy rating of windows is higherbels on commercially available insulation mate- when they have an argon or krypton gas fill be-rials generally provide evidence of compliance tween the panes, but there is some controversywith recognized safety standards. Documenta- about how rapidly the gas fill escapes when thetion for alternative insulation materials may be window is exposed to the low air pressure of highmore difficult to obtain or assess. altitudes (13). Building owners at high altitudes Recommended insulation levels differ by cli- may decide not to opt for gas-filled windows,mate. While information on residential insula- given the uncertainty of their long-term perfor-tion is readily available, information for other mance at altitude.types of buildings may be more difficult to comeby. However, there are several building-energy AIR SEALINGcalculators that can be used to extrapolate energy Once a building has efficient walls, roof, win-performance, and many utility companies offer dows, and doors, what’s left to improve its en-energy audits for both their residential and com- ergy performance? Studies show that most build-mercial customers. These audits can be a good ings have air leaks that provide escape routes forway to identify potential for improvement, and conditioned (heated and cooled) air (14). Block-participating in audit programs may qualify the ing air leaks with gaskets, caulk, or expandingowner for rebates or technical assistance in un- foam can move a building’s energy performancedertaking energy improvements. up a notch. The most common sources of air leaks As amazing as insulation is, it can’t stand include the sill plate; window and door open-alone as a building’s thermal defense. It’s im- ings; and wall, floor, and ceiling penetrationsportant to team insulation with other energy-ef- such as electrical boxes, plumbing lines, and re-ficient components to achieve good system per- cessed light fixtures.formance, the same way you combine a hat, coat, Ducts should also be sealed, particularly ifand boots to outfit yourself for winter weather. they pass through an unconditioned airspace.Once basic levels of insulation have been Making sure that all of these areas are detailedachieved in the walls, roof, and floor, it’s time to and sealed eliminates most major air leaks.turn attention to preventing energy loss from theother parts of the building. HVAC AND OTHER SYSTEMS WINDOWS/DOORS Insulation, efficient windows and doors, and air sealing all contribute to making the building It’s relatively easy to add insulation to walls, envelope energy efficient, but mechanical sys-roofs, and even floors, but when it comes to doors tems also have a role to play. Functions thatand windows, high prices often frighten consum- aren’t furnished by the natural systems describeders away from the most energy-efficient options. above will need to be provided by mechanicalHowever, eliminating leaky, inefficient doors and electrical systems and appliances. Choos-and windows can significantly improve a ing efficient systems for heating, cooling, venti-building’s energy performance and comfort. It’s lation, and lighting helps to cut energy costs andessentially like getting rid of a large hole in the minimize pollution, and can help support the usewall, since many doors and windows have ex- of renewable energy on site by cutting loads.tremely low thermal resistance compared to solid Useful guidelines are available for evaluating thewalls and roofs. Investing in the most energy- relative efficiency of many appliances and ofefficient doors and windows you can afford is a equipment like furnaces and light fixtures. Onegood choice for your building. standard is the Energy Star certification, which Although there are state-of-the-art applies to a wide range of products. Qualified“superwindows” available that are nearly as products and their manufacturers are listed oninsulative as most walls, they are very expensive the Energy Star website <http://www.energyand probably aren’t warranted, except for very star.gov>. Another directory of energy-efficientspecialized applications where exceptional ther- products, which is updated regularly, is the Con-mal performance is necessary (e.g., coolers). In sumer Guide to Home Energy Savings from the American Council for an Energy-Efficient //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW PAGE 7
  8. 8. Economy, and its companion listing, The Most the site with insulation already installed, or struc-Energy-Efficient Appliances, available through tural insulated panels that can be used for walls,<http://www.aceee.org/consumer guide/ floors, or roofs. Structural insulated panels sand-index.htm>. These inexpensive references can wich a layer of foam between two faces, usuallybe useful aids in finding and selecting energy- made of oriented strand board. They offer ex-efficient equipment. cellent energy performance, because they greatly In buildings where lights are used infre- reduce the number of thermal bridges—uninter-quently, standard incandescent lighting will suf- rupted paths of heat loss—across the wall fromfice, but where lights are used for more than a inside to outside. They also provide good soundfew hours each day, fluorescent lighting is more attenuation, and an experienced crew can as-energy efficient. Either fluorescent tubes or com- semble them quickly. An inexperienced crewpact fluorescent lighting can be used, depend- will take longer to assemble the panels, and maying on the amount of light needed. In situations be reluctant to work with them at all, so it’s im-where lighting is used in temperatures below portant to coordinate the building crew with thefreezing, it’s important to select a ballast that is material that’s going to be used.rated for low-temperature conditions. The most Trusses for roofs are another efficient com-efficient choice for lighting large areas is a high- ponent for buildings. Using roof trusses insteadintensity discharge lamp, typically a metal ha- of building a roof system on-site can save mate-lide lamp. rial and labor costs, although setting trusses of- ten requires a crane. A comparatively efficient building system that has recently grown in popularity is insulat- ing concrete forms. These permanent foam forms Resource Conservation provide an insulative framework into which re- in Agricultural Building inforced concrete is poured to form below- or above-grade walls. Foam forms come in either Construction interlocking blocks or large panels, depending on the particular system. Although some sys- tems claim to be owner-friendly enough for be- ginners to assemble, many companies require a certified applicator on site, to help make sure that There are many different strategies that can the forms are properly braced and leveled, andhelp produce efficient agricultural buildings. that the concrete pour goes smoothly. Insulat-With many types of buildings and many differ- ing concrete form systems are more expensiveent materials, the possibilities are almost endless.A few guidelines can help the builder navigatethe available choices. EFFICIENT SYSTEMS One of the basic tenets of resource-efficientconstruction is to employ building systems thatuse minimal material. Engineered and pre-as-sembled building components can use mate-rial very efficiently, and they also help to elimi-nate waste at the job site and speed construc-tion. Although engineered systems may bemore expensive than conventional frame con-struction, there are situations where assuredperformance, quick assembly, and minimal on-site labor are exactly what the owner needs, andcan offset any added cost. Pre-assembled panels may be conventionalwood-framed wall panels that are delivered toPAGE 8 //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW
  9. 9. than wood framing, but they provide an ex- wall cavities, or mixed with adhesives andtremely durable building that offers thermal per- sprayed onto the interior of industrial buildings.formance, sound attenuation, and fire resistance. Cellulose insulation is renowned for its ability Turning to foundations, an especially re- to prevent air infiltration in addition to furnish-source-efficient system that reduces both exca- ing thermal resistance. There are many cellulosevation costs and cement use is the frost-protected insulation manufacturers located in rural areas.shallow foundation. This system, long in use in These manufacturers often rely on local news-Scandinavia and used by a few builders in the paper recycling to provide their raw material.United States for decades, relies on insulation In addition, there are many recycled plasticaround the foundation perimeter to stabilize a products used in building construction for manyheated building, rather than extending footings different applications. Recycled plastic panelsbelow the frost line. Information on designing are popular in some livestock barns because theyand installing a frost-protected shallow founda- are easier to clean than wooden panels. Centertion is available from the National Association Industries (880 1st Ave. NW, Sioux Center, IAof Home Builders via their website <http:// 51250, 712-722-4049, http://www.center-www.nahb.com/builders/frost.htm>. industries.com/Window.html) makes windows with a recycled plastic frame specifically for ag- RECYCLED MATERIALS ricultural use. Meanwhile, recycled plastic lum- Another approach to resource-efficient build- ber manufacturers offer a variety of posts anding is to use recycled materials. These are mate- dimensional products useful for farm applica-rials that have been removed from the waste tions, including fencing, boardwalks, bridgestream and reprocessed to make another prod- decks, retaining walls, and raised beds. See theuct. Although recycled products are seldom less ATTRA publication Organic Alternatives to Treatedexpensive than conventional materials, they do Lumber for more information on recycled plasticdivert waste and conserve resources and energy lumber products. The American Plasticsin their manufacture. Also, some recycled mate- Council’s Recycled Plastic Products Directory in-rials have performance attributes that make them cludes a section of products for Farming andthe best choice for a particular application. Agriculture, online at <http://sourcebook. Cellulose insulation is typically made from plasticsresource.com/category.asp?/Farmingrecycled newsprint, treated with borate additives +&+Agriculture>.to provide fire and insect resistance. Cellulose REUSED BUILDING MATERIALScan be blown loose into ceilings, wet-sprayed into Unlike recycled products, which are reprocessed into a new form, reused products are salvaged and reapplied in the same form. Most farmers and ranchers are old hands at reus- ing building materials time and again, in one application after another, and in remodeling ex- isting buildings to serve new uses. There is a market for vintage buildings, including agricultural buildings, in reasonably good condition. Even if the whole building is not salvageable for resale, individual components may be. A number of compa- nies specialize in remilling old beams to make flooring, or sell- //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW PAGE 9
  10. 10. ing antique beams intact for reuse. If a farm tos is regulated by law (17). Non-friable formsbuilding project involves demolition of an exist- of asbestos, which are less apt to become airborneing structure, it may be worth checking with a because they are bound in composite materials,professional building-salvage operation to see may appear in unexpected building materials,whether there is market value for the materials. such as old fiber-cement siding, floor tiles, or Conversely, it may be worth considering re- sheet flooring. Although not classified as haz-used materials for new farm structures. The pos- ardous materials, these asbestos-containing ma-sibilities are endless, ranging from old windows terials are not desirable for reuse.for cold frames or greenhouses to salvaged andreused metal roofing (15). (Some landowners ALTERNATIVE TECHNOLOGIEShave even accepted clean gypsum drywall scrap In much of the world, building technologiesfrom building contractors to use as a weed sup- that we might consider alternative in the Unitedpressant and soil amendment in orchards and States are widely accepted and practiced. Somefields. Although the effects of gypsum drywall of these traditional material technologies may bewaste as a soil amendment have been studied in viable and effective options for agricultural build-controlled settings, on a few crops, widespread ings in the United States, providing they arefield application experiences are still lacking adapted to meet safety requirements such as fire(16).) and seismic codes. There are also important cautions to observe The majority of buildings on Earth are actu-in reusing some types of building materials. Old ally built of earth. Earth is obviously a widelypaint on wood is likely to contain lead, so it’s available, low-cost building material, althoughimportant to consider how this wood can be it has some drawbacks in its high maintenancesafely handled and where it can be applied or requirements and seismic instability, as well asdisposed of properly. Other salvaged wood may its comparatively low insulation value. In re-be treated with preservatives that are not desir- gions of the world where earthen building isable for residential or organic agricultural appli- commonplace, there is some concern about soilcations. Also, note that wood that is reused for depletion that could have a negative impact onstructural uses in residences or commercial build- agriculture, but this seems unlikely in the Unitedings will need to be regraded by a certified lum- States. By adapting ancient technologies, today’sber grader in most jurisdictions. earth builders are overcoming many of the dis- Finally, beware of asbestos contamination in advantages associated with earthen constructionused building materials. Asbestos fibers as used and making earth a relevant and useful buildingin insulation are a hazardous material because material for the present day.they can become airborne and be breathed in. Typically massive and thick, earthen wallsThe removal and handling of this type of asbes- have good thermal per- formance because their mass slows the rate at which the temperature inside the building changes. In milder cli- mates, with cool nights and warm days, this thermal mass factor alone may be adequate to maintain a comfort- able temperature. De- signs with thick walls require special consider- ations, since thick walls reduce usable interior space compared to the building’s footprint, and can make door and win-PAGE 10 //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW
  11. 11. dow installation challenging, as well as compli- and a number of medium-density fiberboards.cating daylighting. The fiberboard products, which are commonly Earthen building systems include traditional used for flooring underlayment, cabinets, andadobe block and rammed earth, and systems that shelving, can also be made from other agricul-mix earth and fiber. Modern adaptations of these tural fibers such as bagasse, rice hulls, and hemp.techniques include equipment that fabricates Agricultural fiberboard manufacture is a capital-earth blocks mechanically at the building site and intensive and expensive process, and manyPneumatically Impacted Stabilized Earth (PISE) manufacturers, including some farmer-ownedthat is sprayed onto walls with a hose at high cooperatives, have struggled to establish them-pressure. To help earthen buildings better with- selves in the marketplace. In areas wherestand the weather, systems have been invented strawboard manufacturing facilities are able tothat combine earth with asphalt or gypsum (18). operate successfully, they provide a strong mar-There is even a system developed by architect ket for straw, as well as a useful building prod-Nader Khalili of the Cal-Earth Institute <http:// uct derived from agricultural fiber.www.calearth.org> that uses bags of sand Another building technology based on agri-bonded with barbed wire to build domed struc- cultural fiber, although in a less-processed form,tures. Modern earth-building can make use of is straw-bale building. Originating in Nebraskaequipment that reduces labor requirements, ad- more than 70 years ago, the building system usesditives that improve weather resistance, and en- a running bond of straw bales as walls and hasgineered support structures that enhance seismic enjoyed a revival during the past ten years. Strawperformance. For examples of modern earth- bales have been used to build homes in at leastbuilding in the United States, see the Further 38 states, as well as countless non-residentialResources section. buildings ranging from chicken coops and stor- Earth buildings are worth considering for age sheds to camp dining halls. Straw-bale build-some agricultural applications, particularly in ings may be either load-bearing, in which the balemild climates with good building soil. The best walls support their own weight and the weightbuilding soil contains coarse sand or aggregate, of the roof, or non-load-bearing, in which a con-fine sand, silt, and clay. Although the propor- ventional wood or steel structural framework istions of these constituents can vary somewhat, infilled with bales that provide the wall insula-the ideal building soil mix based on averages has tion. Straw-bale residences are often finishedbeen offered as 23% coarse sand or aggregate, with a cementitious stucco, although it is pos-30% fine sand, 32% silt, and 15% clay (19).Soils that differ substantially from thiscomposition will most likely require ad-ditives for successful earth building. Acareful assessment of the soil at the siteand local sources of soil amendments canhelp determine the suitability of a par-ticular location for an earthen building.A common way to roughly assess soilcomposition is the “jar test” in which asoil sample is placed in a glass jar, cov-ered with water, vigorously shaken, andthen allowed to settle until the water isclear. Coarse aggregates will settle in aband at the bottom, sand and silt in themiddle, and clay on top. Farmers may be particularly inter-ested in building technologies based onagricultural fiber. There are severalmanufactured building materials madefrom straw, including ceiling panels, avariant of the structural insulated panel, //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW PAGE 11
  12. 12. sible to finish interiors with gypsum wallboard Installing water-conserving fixtures and ap-and exteriors with different siding options. In pliances usually saves costs in building operation,some agricultural buildings owners have left bale for both water and the energy needed to heat andwalls unfinished, recognizing that this leaves move it. There are also several options for treat-them vulnerable to damage from livestock and ing used water, ranging from complex closed-loopweather. treatment systems based on the ecological struc- Some farmers have used bales to construct ture of a marsh (20) to less-involved constructedwinter livestock shelters, and intentionally left wetlands (21) or sand filters. In some jurisdic-the bales exposed to serve as emergency food for tions greywater (as opposed to blackwater, orthe animals. In these applications the roof would sewage) can be stored and used for irrigation ofneed to be supported by a separate framework, trees or nonfood vegetation. (See the Greywaterand the walls themselves well supported, to pre- website at <http://www. greywater.com/> forvent their collapse. The weathered bales are then additional information.)removed in the spring, allowing the roof to serve Buildings can also play a role in capturingas a shade shelter during summer. rainwater for either drinking or irrigation. Roof- Straw-bale construction’s recent rise in popu- top water-catchment systems vary in complexitylarity can be partly attributed to its intuitive, eas- from simple rain barrels placed at the bottom ofily grasped assembly process. Many owners gutters to systems that collect runoff that is storedhave reduced building costs by investing their in a cistern and treated for drinking. For moreown sweat equity or employing work parties of information on designing and installing rainwa-unskilled labor. However, it is important to rec- ter collection systems, see the Further Resourcesognize that the wall system is typically less than section.15% of a building’s cost, so the savings providedby a homegrown wall system are limited. Alsonote that subcontractors (i.e., electrical, cabinetry,drywall, etc.) may charge more when working Summarywith an unfamiliar construction system thatforces them to modify their standard installationpractices. Designing and constructing agricultural When straw-bale walls are well protected buildings with efficiency in mind saves money,from moisture by a good foundation, a sound energy, and resources. Employing strategies suchroof, and a good exterior covering, they offer a as natural ventilation, passive solar heating, anddurable structure with good thermal perfor- daylighting are some of the ways that buildingmance. Few buildings can be as resource effi- owners can put natural systems to work for them.cient, or as locally derived, as a straw bale build- By combining energy efficiency and renewableing. energy options, agricultural buildings can move toward energy independence. And finally, agri- cultural buildings can be built from a range of resource-efficient materials geared to meet almost Other Efficiency any need, whether that be for a temporary struc- Strategies for ture or a high-performance specialty building. Agricultural Buildings Energy and material are the primary re-sources used in buildings. When the use of theseresources during construction and operation isreduced, the cost of a building and its impact onthe environment are both lessened. There areadditional opportunities to make buildings moreefficient, as well.PAGE 12 //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW
  13. 13. 10) Wilson, Alex, and Peter Yost. 2001. Building-Integrated Photovoltaics: References Putting Power Production Where It Belongs. Environmental Building News. March. p. 1, 8-14.1) U.S. Green Building Council 11) North Carolina Solar Center. 1998. Passive 1015 18th St. NW, Suite 805 and Active Solar Water Heating Systems. Washington, DC 20036 North Carolina Solar Center Factsheet (202) 82-USGBC SC104 . Accessed September 2002. <http:/ info@usgbc.org /www.ncsc.ncsu.edu/fact/ <http://www.usgbc.org> 04pasdhw.html>2) Energy Star 12) Rocky Mountain Institute. No date. (888) STAR YES Energy Efficiency: First Things First. http://www.energystar.gov Rocky Mountain Institute. Accessed3) National Association of Home Builders August 2002. < http://www.rmi.org/ Research Center sitepages/pid195.php> (National Green Building Conference, 13) Yost, Peter, and Alex Wilson. 2000. High Green Building Awards and Energy Elevation Problems Jeopardize Gas-Fill Value Housing Awards) Windows. Environmental Building News. 400 Prince George’s Boulevard April. p. 1, 15-18. Upper Marlboro, MD 20774 (301) 249-4000 14) Krigger, John. 2000. Residential Energy. (800) 638-8556 Third Edition. Saturn Resource <http://www.nahbrc.org> Management, Helena, MT. p. 67-95.4) Watson, Donald and Kenneth Labs. 1983. 15) Corson, Jennifer. 2000. The Resourceful Climatic Building Design. McGraw-Hill, Renovator. Chelsea Green Publishing, New York, NY. p. 3–18. White River Junction, VT. 157 p.5) Rocky Mountain Institute. 1998. Green 16) Stehouwer, R.C. 2002. Section 9: Development. John Wiley & Sons, New Nontraditional Soil Amendments. The York, NY. p. 124–255. Agronomy Guide. Penn State University. Accessed August 2002. <http://6) Efficient Windows Collaborative. No date. agguide.agronomy.psu.edu/CM/Sec9/ Benefits: Energy & Cost Savings. Sec9toc.html> Accessed August 2002. <http:// www.efficientwindows.org/ 17) Anon. 2001. Safety and Health Topics: energycosts.html> Construction: Asbestos. U.S. Department of Labor Occupational Safety & Health7) Anon. 2002. Daylighting: Many Designers Administration. Accessed August 2002. are Still in the Dark. Architectural Record. <http://www.osha-slc.gov/SLTC/ June. Accessed online at <http:// constructionasbestos/index.html> www.archrecord.com/CONTEDUC/ ARTICLES/06_02_3.asp> 18) Middleton, G.F. 1987. Earth-Wall Construction, Fourth Edition. CSIRO8) Bender, Roger, and Richard Stowell. 1998. Division of Building, Construction and Chimneys: A Natural Ventilation Engineering, North Ryde, NSW, Alternative for Two-Story Barns. Ohio Australia. p. 59-61. State University Fact Sheet. Accessed August 2002. <http://ohioline.osu.edu/ 19) McHenry, Paul Graham Jr. 1984. Adobe aex-fact/0115.html> and Rammed Earth Buildings. University of Arizona Press, Tucson, AZ. 217 p.9) Brown, G.Z., and Mark DeKay. 2001. Sun, Wind & Light. John Wiley & Sons, New York, NY. p. 188–200. //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW PAGE 13
  14. 14. 20) Living Machines, Inc. Sun, Wind & Light: Architectural Design 125 La Posta Road Strategies, second edition. 2001. By G.Z. 8018 NDCBU Brown and Mark DeKay. John Wiley and Taos, New Mexico 87571 Sons, New York, NY. 382 p. (505) 751-4448 An in-depth technical reference addressing <http://www.livingmachines.com> analysis techniques, design strategies, and21) Anon. No date. Constructed Wetlands for strategies for supplementing passive systems. Wastewater Treatment. Partnership for Advancing Technology in Housing (PATH) Technology Inventory. Accessed August 2002. <http://www.toolbase.org/ Web-based Resources tertiaryT.asp?DocumentID=2158&Category ID=1071> Adobe International http://www.adobe-block.com/ Further Resources Portable equipment for mechanically manu- facturing earthen blocks at the building site. Daylighting CollaborativeBuilder’s Guide. 2000. By Joseph Lstiburek. http://www.daylighting.org Building Science Corporation, Westford, Information on daylighting buildings, includ- MA. ing benefits of daylighting and an extensive The Builder’s Guide series from the Energy how-to section with interactive online and Environmental Building Association worksheets. Case-study buildings are also presents a systems approach to designing and featured. building healthy, comfortable, durable, energy Design Recommendations for Natural efficient, and environmentally responsible Ventilation Systems homes. Separate versions are available for http://www.ae.iastate.edu/ each climate type: Cold, Mixed, Hot/Humid design_recommendations.htm and Hot/Dry. $40 each from EEBA, <http:// www.eeba.org>. An electronic publication on natural ventila- tion for livestock facilities from the Depart-Climatic Building Design. 1983. By Donald ment of Agricultural and Biosystems Engi- Watson and Kenneth Labs. McGraw Hill neering at Iowa State University that provides Book Company, New York, NY. 288 p. guidelines for placing buildings and sizing This comprehensive reference presents prin- ventilation openings. ciples of climatic design related to ventilation, Designing with the Pilkington Sun Angle cooling, solar gain, and more, as well as Calculator practices and supplemental climatic data. http://www.sbse.org/resources/sac/Serious Straw Bale. 2000. By Paul Lacinski pnasac.htm#thesac and Michel Bergeron. Chelsea Green Detailed online information on how sun angle Publishing, White River Junction, VT. calculations are performed and applied in 371 p. building design. Includes discussions of solar Billed as “A Home Construction Guide for All orientation, designing overhangs, daylighting, Climates,” this reference addresses different and solar heat gain. elements of straw-bale structures, as well as finish options, moisture studies, and experi- mental constructions.PAGE 14 //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW
  15. 15. Landscaping for Energy Efficiency Solar Water Heatinghttp://www.eren.doe.gov/erec/factsheets/ http://www.eren.doe.gov/erec/factsheets/landscape.pdf solrwatr.html A factsheet available as a PDF file from the A basic factsheet on residential solar water- Energy Efficiency and Renewable Energy heating technology, from the U.S. Department Clearinghouse on using trees and other of Energy Office of Energy Efficiency and landscaping to help mitigate hot and cool Renewable Energy. temperatures in different climates and micro- SunAngle calculator climates. http://www.susdesign.com/sunangle/Lawrence Berkeley National Laboratory— Online shareware that can be used to calculateWindows & Daylighting Group optimal angles for solar design, for a fee of $10http://windows.lbl.gov/ for individuals, or $25 for professionals. Information on daylighting products and Texas Water Development Board’s page on controls. Rainwater HarvestingNCAT Center for Resourceful Building http://www.twdb.state.tx.us/assistance/Technology conservation/Rain.htmhttp://www.crbt.ncat.org Offers the PDF version of the Texas Guide to Information on resource conservation in Rainwater Harvesting and a list of rainwater buildings, including a searchable database of catchment systems, services, and equipment manufacturers of efficient systems, recycled providers. and reused building materials, as well as alternative building technologies.Passive Solar Design for the Homehttp://www.eren.doe.gov/erec/factsheets/passive_solar.html By Tracy Mumma NCAT Agricultural Energy Specialist A fact sheet from the U.S. Department of Energy Office of Energy Efficiency and Edited by Paul Williams Renewable Energy that explains the basic principles of how passive solar strategies can Formatted by Gail Hardy help heat and cool homes. November 2002Rainwater Harvesting Wizardhttp://www.captured-rainwater.com/ A fee-based information website where consul- tation on rainwater harvesting system design IP220 and equipment is provided to answer online inquiries. The electronic version of Efficient Agricul-Rammed Earth Works tural Buildings: An Overview is located at:http://www.rammedearthworks.com/ HTML Founded by David Easton, this is a leading h t t p : / / w w w. a t t r a . n c a t . o r g / a t t r a - p u b / company in the research and development of agbuildings.html modern earth construction technologies, PDF including rammed earth and variations such http://www.attra.ncat.org/attra-pub/PDF/ as PISE. agbuildings.pdf //EFFICIENT AGRICULTURAL BUILDINGS: AN OVERVIEW PAGE 15