SBIR-STTR Award

The USDA reports that during 2006, per bred cow, the cost of concentrates and supplemental feed and harvested forages amounted to 64% of total feed cost (calculated at market price). Whereas, aggregate cost for pasture (cropland, private and public lands), calculated at market rental rate, amounted to 36% of total feed cost. This indicates that profitability improvement could be realized by changing from feed-lot based to pasture-based operations. 2007 and 2008 delivered unprecedented increases in energy costs that are passed on to the consumer. Unfortunately, every level of the food-supply chain, up to the consumer, suffers economically. A goal of this research is to allow ranchers to safely pasture grazing stock throughout the year. This could eliminate the practice of moving livestock herds to feed-lots to over-winter in order to provide water and feed, a practice that has been shown to produce environmental consequences. For example, concentrated numbers of cattle in feed-lots are shown to increase methane emissions, accumulate concentrations of unusable manure, making it a pollutant; and byproducts such as organic matter, urea, ammonia, nitrous oxide, phosphorus, carbon dioxide, pathogens, antibiotics, and hormones are released into the ground and air. These byproducts can degrade surface water, ground water, and soil, posing health hazards to humans and animals. A safe, reliable, low-cost, self-sufficient heating system is needed to prevent stock tank freezing. Z4 Energy Systems, LLC will explore a solar water heating approach using a solar collector and heat exchange system. The product vision is a relocatable system that could be clamped on the side of any existing stock tank, and is sized to fit in the bed of a pick-up. Built-on fencing and attachment points for standard corral panels to prevent livestock damage will also be investigated. For the Phase I project, feasibility of a full system design will be assessed through computer modeling and fabrication of a preliminary prototype that will be tested for two wintertime months. In Phase II, at least one full prototype will be field-tested through a Wyoming winter. OBJECTIVES: The overall goal of this Phase I project is to prove technical and economic feasibility of a safe, reliable, low-cost, self-sufficient, relocatable, solar powered stock tank heating system to provide access to open water and to adequately support production livestock herds during winter weather. Methods to be investigated will employ a concentrated solar collector combined with a loop heat pipe. Successful results achieved from three major technical objectives will prove feasibility and support further development: 1. Established thermodynamic requirements for the tank heating system to de-ice approximately a two foot sized opening during freezing winter temperatures, using concentrated solar energy. Identified design targets, will consider temperature range, solar conditions and stock tank sizes. 2. Design, specifications, detailed drawings, and a 3D model for at least two potential equipment designs that include: materials and component selection, fabrication techniques, solar heating method; methods for assembly and disassembly for shipping and relocation, connection to various types of livestock tanks, protection for the equipment and livestock; and cost analysis. 3. A field-tested prototype, produced from technical objective #2 findings, that has met the design goals from technical objective #1 through at least two months of winter temperatures. Project outputs will include computer models, prototype test and demonstration site, a website documenting research activities and results, and a working prototype with documented field-tests. Consultation agreements with University of Wyoming College of Engineering Associate Professor Paul Dellenback and Senior Research Scientist Scott Morton provide for dissemination of project activities and results to staff and university students; and project information will be further disseminated through press releases, Z4 Energy System, LLC's periodic mail communications with the Wyoming agricultural community, regularly attended poster presentations, subsequent commercialization activities and partnership negotiations. APPROACH: Phase I feasibility will be established by developing a full system design and constructing a preliminary prototype that will be tested for two months. To produce the design, mathematical modeling based on thermodynamics analysis will be employed. Data will be collected for stock tank sizes and materials, climate conditions and winter solar insolation. Manufacturer's data for solar concentrators and heat-pipe configurations and materials will be collected, tabulated and analyzed to determine likely heating effectiveness, and computer simulations will be developed. This systematic approach will eliminate trial-and-error factors, prior to prototype construction, that would likely otherwise be experienced. A prototype will be hand-assembled by the PI/PD, and connected to a typical stock water tank in Buford, Wyoming, at an elevation of 8,000 ft. The prototype will operate during November and December, and tank ice coverage will be monitored and documented. Based on test results, design adjustments will be made. This will allow fabrication of the final, production-ready prototype upon commencement of Phase II and will permit the product to move quickly into a rigorous testing regimen through a winter season that will accelerate the product's path to market. Phase I research will progress in a methodical fashion from identifying the range of operating requirements, materials and methods to achieve operating requirements, through prototype fabrication and testing: Stage 1 will result in the target range of actual winter weather conditions. Stage 2 will result in the selection of at least 2 potential design shapes for solar collectors, concentrators, heat pipes and support structures to begin computer modeling. Stage 3 will result in a range of suitable materials, construction techniques and other considerations, such as design life and fabrication constraints. Stage 4 will result in cost analysis. Stage 5 will result in preliminary prototype design, drawings and specifications. Stage 6 will result in a fabricated, working prototype. Stage 7 will conclude with documentation of a 2 month wintertime test and any necessary design modifications. Anticipated technical problems that will be addressed as required include: A completely passive heat cycle between the concentrated solar collector and water tank may be difficult to achieve. Alternative methods to force the heated working fluid downwards into the stock tank will be considered, such as a employing a solar pump. Success will be established if approximately a two foot sized opening is available in a stock water tank, so livestock could access water during winter temperatures, at the time of day when they normally drink. This performance target was developed from Wyoming rancher surveys

The SSTH directly responds to a need that was declared by Wyoming ranchers in more than 300 surveys collected during Wyoming agriculture tradeshows between 2007 and 2011. Nationwide, the National Oceanic Atmospheric Administration (NOAA) weather maps indicate that 29 entire states plus portions of 7 more endure freezing temperatures for at least 4 months annually. In this combined area, an estimated 663,000 agricultural producers raise beef cattle, sheep and bison, which represent 43% of the nation's livestock producers. The 2007 USDA Census of Agriculture reports beef production costs increased 30% overall between 2002 and 2007, with feed purchases showing the highest increase, up 45%. The SSTH will help improve ranching economics by cutting costs as well as opening the door to the growing market for higher-priced organic, natural and grass-fed markets. SSTH solves the problem of stock water tank freeze-over without recurring costs of fuel and grid-provided electricity. This enables longer pasture grazing which reduces the need to purchase and transport expensive harvested forages, facilitates better pasture utilization and grazing management, reduces the need for feed-lot utilization, and the time and cost to relocate animals. Pasture-raising livestock year-around also mitigates environmental problems caused by large numbers of animals in a confined space, such as high concentrations of manure that becomes a pollutant, and byproducts such as organic matter, urea, ammonia, nitrous oxide, phosphorus, carbon dioxide, pathogens, antibiotics and hormones that are released directly into the ground and air, degrading ground and surface waters and soil, and posing health hazards to humans and animals. SSTH will provide a sustainable solution to winter time tank freezing. The most common method of de-icing stock tanks is electric tank heaters, but for remote pastures without electricity this is not an option, and the few commercially available solutions have temperature, animal volume, or cost limitations: (1) Solar and wind powered aerators are ineffective below +10 degrees F., (2) Solar and geothermal "drinkers" service few animal at a time, per drinking station, (3) Propane-fired heaters have ongoing costs ranging from $1.87 to $3.97 per gallon, and (4) Wind and solar electricity generating equipment adapted for water heating has high up-front cost, in the range of $14,000 to $22,000, plus installation. According to the Wyoming surveys, non-commercial methods commonly employed to keep livestock water open are (1) 38% manually break ice with an ax or steel bar, (2) 26% run water continuously so the ground water melts through the ice layer (often employed with solar and wind-powered pumps), even though this practice wastes water and forms dangerous ice around the tank base, (3) 5% abandon pastures and relocate herds where water can be kept open, often in corrals or feed lots, as well as home-devised remedies that use combinations of insulation, geothermal sources, various methods of agitation and wood fires.