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This further investigation focuses on defining aquaponic classification criteria at the enclosure level to complement existing system-level definitions. The enclosure types discussed here work with different construction systems, levels of technological control, passive climate control strategies, and energy sources to achieve an appropriate indoor climate. The best application of each enclosure typology depends primarily on the size of operation, geographic location, local climate, targeted fish and crop species, required parameters of the systems it houses, and the budget. This study identifies five different enclosure typologies and defines the characteristics of indoor spaces that house aquaculture infrastructure.
This classification includes four categories of greenhouses — medium-tech greenhouses, passive solar greenhouses, high-tech greenhouses, and rooftop greenhouses — that are applicable to commercial-level aquaponic operations (Table 21.2). Existing greenhouses may not exactly fit a single typology, but fall within a spectrum from medium-tech to high-tech by selectively incorporating active and passive environmental control techniques.
Medium-Tech Greenhouses Greenhouses with intermediate levels of technology to control the indoor climate include freestanding or gutter-connected Quonset (Nissen hut type), hoop house (polytunnel) and even-span greenhouses. They are usually covered with double polyethylene film (PE) or rigid plastic panels, such as acrylic panels (PMMA) and polycarbonate panels (PC). These greenhouses are less expensive to install, though film cladding needs to be replaced frequently due to rapid deterioration caused by constant exposure to UV radiation (Proksch 2017). These greenhouses protect crops from extreme weather events and to some extent pathogens, but they offer only a limited level of active climate controls. Instead, they rely on solar radiation, simple shading systems, and natural ventilation. With their limited ability to modify growing conditions within a certain range, medium-tech greenhouses are rarely used for housing aquaponic farms in cold climates. This is because the high initial investment into the hydroponic and aquaculture components requires a stable environment and reliable year-round production to be commercially viable.
Aquaponic operations in warmer climates have successfully demonstrated the use of medium-tech greenhouses that employ evaporative cooling and simple heating systems. For example, Sustainable Harvesters in Hockley, Texas, USA uses a simple Quonset greenhouse (12,000 sf/1110 msup2/sup) for year-round lettuce production without relying on extensive supplemental heating or lighting. Ouroboros Farms in Half Moon Bay, California, USA uses an existing greenhouse (20,000 sf/1860 msup2/sup) to produce lettuce, leafy greens, and herbs (Fig. 21.4). Due to the mild climate, the farm uses primarily static shading and little supplemental heating and cooling. Both farms, as many smaller medium-tech operations, place their fish tanks in the same greenhouse space as the hydroponic crop growing system. The farms grow fish species that tolerate a wide temperature range (tilapia) and shade aquaculture tanks to prevent overheating and algae growth.
Table 21.2 Comparison of case studies by enclosure typologies
table thead tr class="header" thCEA type/th th Case studies /th th Construction system /th th Controls /th th Growing seasonsupa/sup and latitude /th th Hardiness zonesupb/sup /th /tr /thead tbody tr class="odd" td rowspan=6 Medium-tech greenhouses/td td rowspan=3 Ouroboros Farms, Half Moon Bay, CA, USA (20,000 sf/1860 msup2/sup) /td td rowspan=3 Existing, gutterconnected GH with two even spans, clad with single-pane glass, fish tanks in GH /td td rowspan=3 Static shading, shading curtains /td td rowspan=2 319 days/ 10.6 months /td td 10a /td /tr tr class="even" td 30 to 35 ˚F /td /tr tr class="odd" td 37.5˚ N /td td -1.1 to 1.7 ˚C /td /tr tr class="even" td rowspan=3 Sustainable Harvesters, Hockley, TX, USA (12,000 sf/1110 msup2/sup) /td td rowspan=3 Quonset frame, multi-tunnel (3) GH, clad with PE- film and rigid plastic panels, fish tanks in GH /td td rowspan=3 Evaporative cooling, forced ventilation /td td rowspan=2 272 days/ nine months /td td 8b /td /tr tr class="odd" td 15 to 20 ˚F /td /tr tr class="even" td 30.0 ˚N /td td -9.4 to 6 .7 ˚C /td /tr tr class="odd" td rowspan=6Passive solar greenhouses/td td rowspan=3 Aquaponic solar greenhouse, Neuenburg am Rhein, Germany (2000 sf/180 msup2/sup) /td td rowspan=3 (Chinese) solar greenhouse, with adobe wall as additional thermal mass, clad with ETFE film, fish tanks in GH /td td rowspan=3 Custom-built photovoltaic modules for shading and energy production /td td rowspan=2 202 months/ 6.6 months /td td 8a /td /tr tr class="even" td 10–15 ˚F /td /tr tr class="odd" td 47.8 ˚N /td td - 12.2 to -9.4 ˚C /td /tr tr class="even" td rowspan=3 Eco-ark greenhouse at Finn & Roots, Bakersfield, VT, USA (6000sf/ 560 msup2/sup) /td td rowspan=3 Solar greenhouse, earth sheltered, steep angle of south facing roof (ca. 60), thick insulation, special solar collecting glazing, fish tanks in northern, subterranean side /td td rowspan=3 Wood-fuelled radiant heat, energy curtain, ventilation with stackeffect, supplemental LED lighting /td td rowspan=2 108 days/ 3.6 months /td td 4a /td /tr tr class="odd" td -30 to -25 ˚F /td /tr tr class="even" td 44.8˚ N /td td -34.4 to -31.7 ˚C /td /tr tr class="odd" td rowspan=6High-tech greenhouses/td td rowspan=3 Superior Fresh Farms, Hixton, WI, USA (123,000 sf/11,430 msup2/sup) /td td rowspan=3 Venlo-style, gutterconnected, (20 41 bays), clad with glass, fish tanks in separate building /td td rowspan=3 Computer-controlled CEA environment, supplemental LED lighting, /td td rowspan=2 122 days/ 4.1 months /td td 4b /td /tr tr class="even" td -25 to -20 ˚F /td /tr tr class="odd" td 44.4 N /td td -31.7 to -28.9 ˚C /td /tr tr class="even" td rowspan=3 Blue Smart Farms, Cobbitty, NSW, Australia (53,800 sf/5000 msup2/sup) /td td rowspan=3 Venlo-style, gutterconnected, (14 18 bays), clad with glass, two-story construction, fish tanks on the lower level /td td rowspan=3 Computer-controlled CEA environment biological pest control /td td rowspan=2 300 days/ 10 months /td td 9b /td /tr tr class="odd" td 25 to 30 ˚F /td /tr tr class="even" td 34.0˚S /td td -3.9 to -1.1 ˚C /td /tr tr class="odd" td rowspan=6Rooftop greenhouses/td td rowspan=3 Ecco-jäger Aquaponik Dachfarm, Bad Ragaz, Switzerland (12,900 sf/1200 msup2/sup) /td td rowspan=3 Venlo-style, gutterconnected, (7 13 bays), clad with glass, fish tanks on the lower level /td td rowspan=3 CEA environment, supplemental LED lighting, use of exhaust heat from cooling facility /td td rowspan=2 199 days/ 6.6 months /td td 7b /td /tr tr class="even" td 5 to 10 ˚F /td /tr tr class="odd" td 47.0˚ N /td td -15.0 to -12.2 ˚C /td /tr tr class="even" td rowspan=3 BIGH’s Ferme abat-toir, Brussels, Belgium (21,600 sf/2000 msup2/sup) /td td rowspan=3 Venlo-style, gutterconnected, (15 10 bays), clad with glass, fish tanks on the lower level /td td rowspan=3 CEA environment, supplemental LED lighting /td td rowspan=2 224 days/ 7.3 months /td td 8b /td /tr tr class="odd" td 15 to 20 ˚F /td /tr tr class="even" td 50.8˚ N /td td -9.46 to -6.7 ˚C /td /tr tr class="odd" td rowspan=6Indoor growing spaces/td td rowspan=3 Urban Organics, Schmidt’s Brewery, St. Paul, MN, USA (87,000 sf/8080 msup2/sup) /td td rowspan=3 Steel-frame warehouse, highly insulated, stacked growing, fish tanks in separate space /td td rowspan=3 Fluorescent UV lighting, computer-controlled CEA environment /td td rowspan=2 140 days/ 4.7 months /td td 4b /td /tr tr class="even" td -25 to -20 ˚F /td /tr tr class="odd" td 45.0˚ N /td td -31.7 to 28.9 ˚C /td /tr tr class="even" td rowspan=3 Nutraponics, Sherwood Park, AB, Canada (10,800 sf/1000 msup2/sup) /td td rowspan=3 Steel-frame warehouse, highly insulated, stacked growing, fish tanks in separate space /td td rowspan=3 LED lighting, computer-controlled CEA environment /td td rowspan=2 121 days/4 months /td td 4a /td /tr tr class="odd" td -30 to -25 ˚F /td /tr tr class="even" td 53.5˚ N /td td -34.4 to -31.7 ˚C /td /tr /tbody /table
supa/supFrost-free growing season, National Gardening Association, Tools and Apps, https://garden.org/ apps/calendar/
supb/supBased on the USDA Hardiness Zone Map, which identifies the average annual minimum winter temperature (1976—2005), divided into 10 F zones. Plant Maps, https://www.plantmaps.com/ index.php
Passive Solar Greenhouses This greenhouse type is designed to be solely heated by solar energy. Substantial thermal mass elements, such as a solid north-facing wall, store solar energy in form of heat that is then re-radiated during colder periods at night. This approach buffers air temperature swings and can reduce or eliminate the need for fossil fuels. Solar greenhouses have a transparent south-facing side and an opaque, massive, highly insulated north-facing side. The integration of large volumes of water in form of fish tanks is an asset for the thermal performance of this greenhouse type. Furthermore, the tanks can be located in areas of the greenhouse that are less suited for plant cultivation or partly submerged into the ground for added thermal stability.
img src="https://cdn.aquaponics.ai/thumbnails/9ab2af1a-4c94-4753-804b-11f0dac8a7eb.jpg" style="zoom:75%;" /
Fig. 21.4 Ouroboros Farms (Half Moon Bay, California, USA)
The Aquaponic solar greenhouse (2000 sf/180 msup2/sup), developed and tested by Franz Schreier, has proven as a suitable environment for housing a small aquaponic system in southern Germany. The greenhouse collects solar energy through its south-facing arched roof and wall clad with ethylene tetrafluoroethylene (ETFE) film. Heat is stored in partially submerged fish tanks, floor, and adobe-clad northern wall to be dissipated at night. The greenhouse's custom-built photovoltaic (PV) panels transform solar radiation into power. Located in the colder climate of Vermont, USA, the Eco-Ark Greenhouse at the Finn & Roots farm (6000 sf/560 msup2/sup) houses an aquaponic system that works with a similar passive solar approach. The greenhouse has a steep (approx. 60˚) south-facing transparent roof with special solar-collecting glazing (Fig. 21.5). Its highly insulated, opaque northern side is submerged into a hillside and houses the fish tanks. In addition to these passive controls, the Eco-Ark has a radiant floor heating that supplements heating during the coldest seasons.
High-Tech Greenhouses Venlo-style, high-tech greenhouses that feature a high level of technology to control the indoor climate are the standard for commercialscale hydroponic CEA. High-tech greenhouses are characterized by computerized controls and automated infrastructure, such as automatic thermal curtains, automatic lighting arrays, and forced-air ventilation systems. These technologies enable a high level of environmental control, though they come at the cost of high energy consumption.
img src="https://cdn.aquaponics.ai/thumbnails/32392581-63cb-423e-b8b6-baf400d07aed.jpg" style="zoom:75%;" /
Fig. 21.5 Eco-Ark Greenhouse at Finn & Roots Farm (Bakersfield, Vermont, USA)
Some large-scale commercial aquaponic farms use this greenhouse typology for their plant production, such as Superior Fresh farms, located in Hixton, Wisconsin, USA (123,000 sf/11,430 msup2/sup), with the aquaculture systems housed in a separate opaque enclosure. Automated supplemental LED lighting and heating enables Superior Fresh farms to cultivate leafy greens year-round despite lack of daylight in the winter, where the natural, frost-free growing season lasts only 4 months. Automated systems for internal climate control allow high-tech greenhouses to be operated anywhere in the world — Blue Smart Farms greenhouse uses an array of sensors to optimize shading during hot Australian summers.
Thanet Earth, the largest greenhouse complex in the UK, is located in the southeast of England. Its five greenhouses cover more than 17 acres (7 hectares) each, growing tomatoes, peppers, and cucumbers using hydroponics (Fig. 21.6). This enterprise is powered by a combined heat and power system (CHP) that provides power, heat, and COsub2/sub for the greenhouses. The CHP system operates very efficiently and channels excess energy to the local district by feeding it into the local power supply grid. In addition, computer-controlled technologies such as energy curtains, high-intensity discharge supplemental lighting, and ventilation regulate the indoor growing conditions.
Rooftop Greenhouses This most recent type includes greenhouses built on top of host buildings, either as retrofits of existing structures or as part of new construction. Due to high land costs, saving space is increasingly important to aquaponic farms in urban contexts. Connecting a greenhouse to an existing building is one strategy for urban farmers looking to revitalize underused space and find a central location in the city. Rooftop greenhouses are already used by commercial-scale hydroponic growers but are a relatively rare enclosure type for aquaponic farms due to the additional weight of water which can strain existing structures beyond their loading capacity. The few rooftop aquaponic farms that currently exist prioritize lightweight water distribution systems (nutrient film technique or media-based growing rather than deep water culture) and locate their fish tanks on the level below the crop growing space due to relatively decreased demand for natural light.
img src="https://cdn.aquaponics.ai/thumbnails/d3c2c5a9-cd6e-4ed4-86c1-49691ee052ff.jpg" style="zoom:75%;" /
Fig. 21.6 Thanet Earth, state of the art greenhouses with combined heat and power provision, (Isle of Thanet in Kent, England, UK)
Two rooftop farms with high-tech aquaponic systems have recently opened in Europe. Both consulted with Efficient City Farming (ECF) farm systems consultants in Berlin. Ecco-jäger Aquaponik Dachfarm in Bad Ragaz, Switzerland sits on top of a distribution center of a family-owned produce company. The Venlo-style rooftop greenhouse (12,900 sf/1200 msup2/sup) is located on a two-story depot building; the fish tanks are installed on the floor below the greenhouse. By growing leafy greens and herbs on their rooftop, Ecco-jäger reduces the need for transportation and can offer produce immediately after harvest. In addition, the farm takes advantage of waste heat generated by its cold storage to heat the greenhouse. BIGH's Ferme Abattoir (21,600 sf/2000 msup2/sup) is a larger version of a similar Venlo-style rooftop greenhouse (Fig. 21.7), which occupies the roof of the Foodmet market hall in Brussels, Belgium. These early examples point to further potential to optimize both aquaponic and envelope performance through connecting water, energy, and air flows between farm and host building, known as building-integrated agriculture (BIA). Currently, research is being done on the flagship hydroponic integrated rooftop greenhouse located on the building shared by the Institute of Environmental Science and Technology (ICTA) and the Catalan Institute of Paleontology (ICP) at the Autonomous University of Barcelona (UAB) to dermine the benefits of full building integration, although no such example exists in the field of aquaponics to determine the benefits of full building integration, although no such example exists in the field of aquaponics.
img src="https://cdn.aquaponics.ai/thumbnails/fb4fdcd2-2461-4190-9d42-287f24c50e25.jpg" style="zoom:75%;" /
Fig. 21.7 BIGH Ferme Abattoir with the high-tech greenhouse in the background (Brussels, Belgium)
Indoor growing spaces rely exclusively on artificial light for plant production. Often, these growing spaces are highly insulated and clad in an opaque material, originally intended as storage or industrial manufacture rooms. Indoor growing spaces typically have better insulation than greenhouses due to the envelope material, though cannot rely on daylighting or natural heating. The assumption is that this typology is better suited to extreme climates, where temperature swings are of larger concern than lighting (Graamans et al. 2018), though more conclusive research is needed.
Urban Organics operates two commercial-scale indoor growing aquaponic farms within two refurbished breweries in the industrial core of St. Paul, Minnesota, USA. The two farms cultivate leafy greens and herbs in stacked growing beds illuminated by fluorescent grow lights (Fig. 21.8). Their second site allows Urban Organics to tap into the brewery infrastructure around an existing aquifer; the aquifer water needs minimal treatment and is supplied at 10 ˚C to arctic char and rainbow trout tanks. Using existing structures lowered construction costs for Urban Organics and offered the opportunity to revitalize a struggling area of the city. In an even colder climate, Nutraponics grows leafy greens in a warehouse on a rural parcel 40 km outside Edmonton, Alberta, Canada. Since local produce is highly dependent on seasonal temperature swings, Nutraponics gains a competitive edge in the market by employing LED lighting to accelerate crop growth year-round (Fig. 21.9).
img src="https://cdn.aquaponics.ai/thumbnails/0aa00759-4d60-4e68-aa79-f2a6428b3e77.jpg" style="zoom:75%;" /
Fig. 21.8 Urban Organics (St. Paul, Minnesota, USA)
The enclosures for the aquaculture component of aquaponic operations are technically not as demanding as the enclosure design for the hydroponic components since fish do not require sunlight to thrive. Nevertheless, control over indoor growing conditions enables farmers to optimize growth, reduce stress, and draw up precise schedules for fish production which gives their stock a competitive edge in the market (Bregnballe 2015). Aquaculture space enclosures are mainly required to keep water temperatures stable. Fish tanks should be able to support comfortable water temperature ranges for specific fish species, warm-water fish 75-86˚F (24-30˚C) and cold-water fish 54-74˚F (12-23˚C) (Alsanius et al. 2017). Water and room temperature can be controlled most efficiently if fish tanks are housed in well-insulated space with few windows to minimize solar gains during the summer months and temperature losses when the outside temperature drops (Pattillo 2017) as demonstrated in the set-up of the INAPRO enclosure. The large volume of water required for fish cultivation needs to be considered from an architectural perspective, as it carries consequences for structural and conditioning systems within a building.
img src="https://cdn.aquaponics.ai/thumbnails/ddba0cf1-5af4-4d05-83bc-e825fa988640.jpg" style="zoom:75%;" /
Fig. 21.9 Nutraponics (Sherwood Park, Alberta, Canada)