Recipient Organization
TEACH SHARP LLC
10728 N MARTINEAU RD # 249
ELFRIDA,AZ 856109041
Performing Department
(N/A)
Non Technical Summary
Tilapia is a mild, fresh-water fish that has become the 4th most popular seafood in the United States. However, most tilapia is imported, and questionable farming practices in other countries have led to food-safety concerns. When tilapia are grown in clean conditions, they are a safe and nutritious food source. Production of locally-grown, clean, U.S. tilapia promoted through this project contributes to the nation's food supply.The overall purpose of this work is to make production of tilapia (and other warm-water fish) financially viable and sustainable on a small-farm scale. This depends on several factors. The number-one constraint is the need to maintain tropical water temperatures (60° to 100°F) for the fish. This is especially true in the continental U.S. where ambient air temperatures typically go below the 60°F required for the fish to survive. Using expensive nonrenewable energy sources (electric, natural gas, propane) to keep water above 60°F, let alone the optimum 85°F, is too costly to keep fish production profitable. To address this need, our research focuses on heating the water in individual fish tanks via a closed-loop heat-transfer system, using renewable energy as the heat source. Our target customers are small fish-farms in cooler climates that use indoor recirculating aquaculture systems (RAS).Phase I of this work focuses on set-up and implementation of the heat-transfer system within an already-operational indoor RAS stocked with tilapia. Goal 1 is to "Determine capability, efficiency, and limits for a heat transfer system in a RAS to maintain the fish water at acceptable temperatures (70-100°F, 85° ideal)". This is addressed through eight technical questions related to temperatures within the fish tanks, efficiency of the heat transfer system, hot water storage capacity, energy requirements, and flow and/or pressure rates. Data will be obtained through electronic sensors that record water temperatures in individual fish tanks, heat exchangers, and hot-water storage tanks; ambient air-temperatures inside and outside the facility; water pressure and flow rates; and energy used to heat water. Descriptive and comparative statistics will inform further development and replication of the system. Goal 2 is to "Examine impacts of the heat-exchange process on the fish." Technical questions for this goal address fish reactions to the heating process and impacts related to growth rates, breeding and spawning, and social-behavioral. Systematic observational and quantitative data will be collected and analyzed for this goal.Phase II will emphasize continued work toward commercialization. Prototypes will be placed in 4-6 different climatic regions of the United States with various types of renewable energy; these will be operated by trained but independent small farmers. Data from these prototype operations will be used to further refine the technical and educational processes. The goal is to expand commercialization by promoting the RAS tilapia-production systems that utilize the heat-transfer system powered by renewable energy developed in this research, and educating small farmers throughout the country on adding tilapia production as a revenue stream using this system. By enabling small farmers to raise tilapia and other warm-water fish through their most cost-effective, locally-available renewable energy source, the innovations developed in this research will support and improve the sustainability and profitability of fish production as a small-farm enterprise. These efforts can foster a variety of new agricultural enterprises; increase availability of locally-grown foods marketed directly to consumers and through restaurants; support food security through availability and affordability of nutrient-dense foods; and contribute to the well-being of communities.
Animal Health Component
0%
Research Effort Categories
Basic
0%
Applied
0%
Developmental
100%
Goals / Objectives
The overall purpose of this work is to provide small farmers with an economically feasible method for raising warm-water fish such as tilapia in cooler climates (i.e., continental United States), and thereby build profitable small-farm enterprises that provide clean, healthy, fresh food in local communities year round. A critical need for warm-water fish production is to maintain tropical water temperatures (70° to 100°F, 85°F ideal) in a cost-effective way. By using renewable energy rather than expensive nonrenewable energy sources (e.g., electric, natural gas) operating costs can be greatly reduced and small, cool-climate fish farms can better compete with fish farms located in tropical climates.To address this need, this work focuses on exchanging heat in the water of the fish tanks via a closed-loop heat-exchange system using renewable energy as the heat source. The Phase I research funded in this project will yield foundational technology, processes, and knowledge essential for future phases of the work. During this phase we will gather data on set up of necessary trunk lines, manifolds, aquastats, thermostats, and other relative inputs to determine efficient and effective ways to develop the heat-exchange system, using 58 fish tanks ranging in size from 20 to 330 gallons already in place at our research center. The initial research will use solar as the renewable energy source; subsequent phases will incorporate other types of renewable energy (e.g., biomass/wood, geo-thermal). The 8-month Phase I project includes two overall goals with corresponding objectives/technical questions:Goal 1Determine capability, efficiency, and limits for a heat transfer system to maintain the fish water in a recirculating aquaculture system at acceptable temperatures (70-100°F, 85°F ideal).Objectives/Technical Questions1.1 To what extent does the water in the fish tanks stay at 85°F?1.2 What is the vertical variance in fish-tank water temperature when the valve is open and the heat-exchanger (located at the bottom of the tank) is active/hot?1.3 How efficient is the heat transfer (increase in fish tank temperature compared with decrease in storage tank temperature)?1.4 How much hot water storage does it take to keep tank water at 85°F?1.5 How much time is needed to bring water in storage back to 160°F at differing overnight ambient temperatures?1.6 How much energy is required to keep water in storage tanks at 160°F for a 24-hour period in relation to inside and outside ambient air temperatures?1.7 How efficient is the heat exchanger (temperature of the heat-exchange water as it leaves the storage tank compared with its temperature when it returns to the storage tank)?1.8 How do flow and/or pressure rates in the heat-exchanger impact temperature of fish-tank water?Goal 2Examine impacts of the heat-exchange process on the fish.Objectives/Technical Questions2.1 What are the reactions of fish to water-temperature changes at the point of exchange (fish proximity to heat-exchanger)?2.2 How do fish exposed to the heat-exchange process compare with fish raised in similar conditions without heat-exchange process: growth rate, breeding and spawning, social behavioral?
Project Methods
This project takes place in two chronological sections. Section 1, Preparation and Set-up, takes place during the first two months (July-August) and Section 2, Research and Development, during months 3 through 8 (September-February). All Phase I work is done at the Arizona Green Research Center in southeast Arizona, primarily in the aquaculture facility that houses 58 fish tanks stocked with tilapia.During Section 1, Preparation and Set-up, a heat transfer system is added to the existing aquaculture facility. This includes installing a heat exchanger in each fish tank, a photovoltaic (PV) solar system, three water-storage tanks, hot water lines, return lines, kilowatt hour (kWh) meter, and other thermostats and sensors. Infrastructure also is established for data collection and analyses. This includes installing heat sensors in four areas: 1) each of the 58 fish tanks, 2) the water storage tanks used in heat transfer, 3) inside ambient air temperature, and 4) outside ambient air temperature. These sensors send information to an online temperature monitoring unit (TMU) every 5 minutes 24/7; the data are stored in the cloud and backed regularly. The infrastructure also includes preparation of research protocols, data collection instruments, spreadsheets, and analyses based on the methods for each objective as described below.The data collected in the TMU, supplemented with selected manual readings, provide the data sets drawn on for Section 2, Research and Development. The Efforts and Evaluations described below correspond with the objectives and outcomes, and are numbered accordingly. The Evaluations focus on implications for future system development.1.1Effort. Data from TMU: fish tank water temperatures and inside ambient air temperatures. Graph 5-minute interval temperatures, compare with 85°F norm. Summarize using descriptive statistics about points at which water temperatures fall below 85°F.Evaluation. Clear set of data that pinpoints inside ambient air temperatures at which fish tank water temperatures cannot be maintained at 85°F, and yields implications related to heat loss from building.1.2Effort. Manual Data: While heat-exchanger is active/hot, take three temperature readings (fish tank water near heat exchanger, water near surface, and inside ambient air). Note tank number/size. Plot temperature difference between two water locations, size of tank, and ambient air temperature. Summarize using descriptive and comparative statistics about the extent of heat disbursement within the fish tanks.Evaluation. Clear set of data that yields implications about the time required for heat to be disbursed throughout fish tanks, in relation to tank size and ambient air temperatures.1.3 Effort. Manual Data: When heat-exchanger turns on and becomes active/hot, take two temperature readings (fish tank water and storage tank water). Repeat temperature readings when heat-exchanger shuts off. Note tank number/size. Record these data at regular intervals (e.g., weekly), collecting from a representative sample of different-size fish tanks. Summarize using descriptive and comparative statistics about the differences in temperatures between the fish and storage tanks, and resulting implications related to efficiency of the heat transfer system.Evaluation. Clear set of data that enables calculation of temperature changes in fish tanks and thus inches of heat exchanger needed for various size tanks.1.4Effort. Data from TMU: 1) fish tanks water temperature, 2) storage tank water temperature, 3) inside ambient air temperature and 4) outside ambient air temperature. Plot temperatures and identify the points when water storage tanks and fish tanks both are less than 85°F. Overlay inside and outside ambient air temperatures to determine points at which hot-water storage amounts are inadequate.Evaluation. Clear set of data that enables calculation of required size of storage tanks.1.5Effort. Data from TMU: 1) overnight outside ambient air temperatures by time and 2) time-of-day when storage tank water reaches 160°F. Plot ambient air and water temperatures and times. Identify the points when water storage tanks first reach 160°F the following day.Evaluation. Clear set of data that yields implications for calculating required size of solar energy system in relation to size of storage tanks.1.6Effort. Data from TMU: 1) storage tank water temperature, 2) inside ambient air temperature, and 3) outside ambient air temperature. Manually record kWh of energy used to heat water for past 24 hours. Plot each day's energy use and overlay it with storage tank water temperature, ambient inside and outside air temperatures.Evaluation. Clear set of data that enables conversion of incoming energy requirements to BTUs for calculating required size of various renewable energy systems (i.e., for solar, the quantity of solar panels and size of battery bank).1.7Effort. Manual Data: While heat-exchanger is active/hot, take temperature readings of heat-exchange lines for individual tanks: 1) as the hot water from the storage tank leaves the manifold and enters the valve and 2) as the same water returns from the fish tank to the manifold. Also record same-time inside ambient air temperature at fish tank. Plot temperature difference between outgoing and returning lines, size of tank, and ambient air temperature. Summarize using descriptive and comparative statistics about efficiency of the heat exchanger for various size tanks and ambient air temperatures.Evaluation. Clear set of data that enable calculation of BTUs delivered to fish tanks and the BTUs lost outside of the heat-exchange system.1.8Effort. Manual Data: Increase, decrease, and measure flow/pressure rates in heat-exchange lines. Thirty minutes after each adjustment, take manual readings per objectives 1.3 and 1.7. Plot flow/pressure readings and data from 1.3 and 1.7 to find optimal flow/pressure setting. Summarize using descriptive and comparative statistics.Evaluation. Clear set of data that identifies optimal flow rate and yields implications for optimal pump size.2.1Effort. Manual Data: Periodically observe location of fish related to heat-exchanger in tank: 1) when valve is open and heat exchanger is active/hot and 2) when valve is closed and exchanger is not hot. Record on observation instrument (sketch of tank) and/or photos. Note same-time water temperatures and ambient air temperatures. Summarize noting typical and atypical behaviors/locations based on water temperatures at various vertical locations (1.2) and on ambient air temperature.Evaluation. Clear set of data that exposes any atypical behaviors of the fish due to heat exchanger activity.2.2Effort. TMU Data: Water temperature in two tanks of similar size, control heated with vertical electric submersible heater set at 85°F and the other with heat exchanger. Manual Data: 1) Growth rate. Monitor feed amounts and weigh fish at beginning and end of specified time. 2) Breeding/Spawning. Number of spawns per tank. 3) Social-Behavioral. Note any atypical behaviors. Summarize by comparing data from control and heat-exchange tanks, identify any differences and related impacts.Evaluation. Clear set of data that identifies any abnormalities among fish in heat-exchange tank.