Progress 09/01/12 to 08/31/15
Outputs
Target Audience: The target audience for the Solar Stock Tank Heater (SSTH) consists of individuals and businesses that need access to water beneath a layer of ice on a tank, pond or pool; including equipment distributors, installers and service providers who serve these customers. End-user groups include livestock growers who must provide water to animals in remote pastures where grid-provided electricity is unavailable as well as livestock growers who choose to not use power from the grid due to high cost or sustainability; and remote, off-grid home and recreational property owners who use tank-stored water during winter. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?Direct, personal contacts were made through phone conversations, email, and in-person presentations with educational institutions, potential end-users and strategic partners in North America and Asia. Photos and information about the prototypes and design were distributed to interest groups that include commercial and small-farm livestock growers, animal boarding operations, veterinarians, rural co-op and livestock growers organizations, agricultural supply retail outlets, and solar equipment installers and retailers. Personal presentations were made to agricultural equipment distributors; conservation districts and agriculture extension and outreach offices; University of Wyoming College of Agriculture and Natural Resources Extension Department and Department of Ecosystem Science and Management, and College of Engineering and Applied Science professors and student groups; and divisions of the Wyoming State government, including the Wyoming Business Council, Department of Agriculture, and Laramie Rivers Conservation District. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
During this SBIR project, Z4 Energy Systems, LLC developed solar powered equipment to melt ice that forms on the top of livestock watering tanks in freezing weather, providing access to water beneath the ice layer. A fully-tested design was developed, technical issues were resolved, heat transfer performance was optimized, prototypes were fabricated, in-situ testing was concluded with successful results, and manufacture-ready design specifications, drawings and parts list were produced. To maintain healthy livestock, water must be available year around and extreme winter weather presents a challenge to the livestock grower, particularly when the animals are grazed in remote pastures, because water tanks tend to freeze over. Cattle require between 3 and 15 gallons of water per head per day through the winter months, and will typically return to a water source to drink at least twice during the day. When the sun is available, the Z4 Solar Stock Tank Heater melts and maintains a hole in the ice, and prevents the tank from freezing solid. As a backup for consecutive overcast days, the same heater can be powered from a portable generator at 120 or 240 VAC. Access to water allows herds to remain in the pasture as long as feed is available. Ranchers with an underutilized, winter-suitable pasture will be able to fully utilize their grazing resources and improve ranch economics by reducing the amount of feed that must be purchased during the winter season. Pasture-raised livestock herds have lower health risks, and environmental problems caused by large numbers of animals in a confined space are avoided. Year-round grazing may also open the door to premium organic, natural and grass-fed livestock markets. Technical Objective 1: Optimize heat transfer performance verified through Computational Fluid Dynamics (CFD) models and laboratory testing. A mathematical model was developed to simulate performance of the overall SSTH system, which incorporates independent models of the various subsystems: Solar Collectors - Solar collectors investigated during the research fall into two main categories: thermal evacuated tube solar collectors and electric PV solar panels. Evacuated tube solar collector performance was evaluated for daily heat collection and heat loss over a range of average temperatures and wind speeds. Requirements for a solar-thermal collector were based on testing and modeling results in response to varied amounts of sunlight over a range of temperatures as well as a cost benefit analysis. PV panel performance was documented across the same spectrum of environmental conditions, combined with options for solar tracking and battery energy storage. PV system requirements were determined by matching modeled performance to a range of wintertime heat requirements, daily insolation, and temperature range data. Results from evacuated tube solar collector and PV panel array models determined the relative performance of each collector technology versus available solar power, ambient air temperature and wind speed. Both technologies were also evaluated for reliability and economic viability. Heater Coil - CFD analyses determined working fluid velocity, temperature and heat transfer rate considering fluid inlet velocities, turbulence, fluid properties and pipe sizes. The fluid model was then combined with steady-state heat transfer to create a multi-physics finite element model. The final Heater Coil design was determined by matching the total heat transfer rate to a range of possible solar heat collection rates, taking into account material costs and pressure losses as a function of pipe size. Heat Transfer System - Thermodynamics modeling determined the effect on heat transfer from: circulation fluid flow rate, state of the flow, and geometry of the tubing. Circulation pumps were sized to provide optimum flow rates to create a 2 ft. diameter opening in the top ice. The heat transfer rates required to open surface ice with varied freezing winter conditions were used to size the PV array and electric water heating element. PV panel operating voltages and currents were factored into the model and matched to the heating element to ensure the system operated at a maximum power transfer point in sunny conditions, while minimizing power loss in cloudy conditions. Results from the mathematical models and earlier field test data answered the design questions addressed in the proposal and enabled selection of system components and the creation of solid models and fabrication drawings for the prototypes. FEA models were developed for structural components, considering ice, snow and wind loads, and potential animal contact. AASHTO "Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals" served as the basis for designing and validating solar collector and PV panel frames. Technical Objective 2: SSTH prototypes fabricated. Prototype frame components, deicer housings and heater coils were constructed by three different fabricators: University of Wyoming College of Engineering and Applied Science Prototyping Shop, an agricultural equipment manufacturer, and an industrial machine shop contractor. Off-the-shelf components were acquired and Z4 assembled and tested three prototypes at the test site in Buford, Wyoming. Technical Objective 3: Verify de-icing performance and equipment durability by field testing two prototypes through an entire winter season. Software to manage data collection and storage, and process and correlate results was written and tested. Sensor arrays to measure system performance and the effectiveness of heat exchange in the stock tanks were mounted on the prototypes, in the stock tanks, and on a meteorological tower at the test site in Buford, WY. Sensors include: working fluid pressure, temperature and flow rate; voltage and current; stock tank water temperature; air temperature, barometric pressure, humidity, wind speed and direction, and insolation. On-site cameras captured images of the condition of the top ice. Voltage and current data was acquired and stored every second; heat transfer, stock tank water temperature and meteorological data were acquired and stored every minute. Final prototype setup, modifications and testing commenced during February 2014 and continued through August, 2015. Technical Objective 4: Manufacture-ready design and prototypes to prepare for Phase III commercialization. A manufacture-ready design was produced, consisting of plans, drawings, specifications, component lists, and assembly instructions. The final deicing system is simple, rugged and cost-effective, and can be used with most stock tanks. The SSTH includes: (1) PV array sized to meet de-icing requirements established throughout this research project; (2) DC circuit over current protection and disconnects in compliance with the National Electric Code (NEC) to protect electrical components; (3) DC ground fault detection and interruption in accordance with the NEC to provide safety for livestock and personnel; (4) rugged side-clamp electric stock tank deicer powered directly from the DC output of the PV array with thermostat control to prevent overheating. The University of Wyoming College of Agriculture analyzed the financial impact of solar stock tank deicing compared to manually chopping and removing the ice, for a typical Wyoming ranch in Casper, Wyoming and produced a business model and calculation tool. The calculation tool, "Z4 Solar Water Heater Economic Value Tool," is accessible online and can be used to input actual ranch operating data to determine the Return On Investment for the Z4 SSTH for a specific ranching venture.
Publications
- Type:
Websites
Status:
Published
Year Published:
2015
Citation:
http://z4energy.com/Tank_DeIcer.html
- Type:
Websites
Status:
Published
Year Published:
2015
Citation:
https://www.facebook.com/pages/Z4-Energy-Systems-LLC/158699524295737
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Progress 09/01/13 to 08/31/14
Outputs
Target Audience: The target audience for the Solar Stock Tank Heater (SSTH) includes consumers who need surface ice to be melted. End-users located in areas where grid provided electricity is unavailable, inaccessible or cost-prohibitive make up the initial audience, along with consumers who choose to practice sustainability. This includes ranchers with livestock watering tanks in remote pastures, rural facilities with ice-covered walkways and construction companies operating in remote areas that need to thaw ground or warm work area flooring. In collaboration with the University of Wyoming College of Business, College of Agriculture and Natural Resources, and Cooperative Extension Service, regional agricultural product retailers and wholesale distributors, and U.S. ag-equipment manufacturers were contacted and provided detailed information about the SSTH. Construction companies building roads in remote locations were also contacted, along with individual ranchers, rural homeowners and recreational cabin owners. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? Tasks to accomplish remaining goals: 1. Install second prototype 2. Continue field testing 3. Collect and anlyze test data 4. Prepare final plans and specifications of manufacture-ready SSTH
Impacts
What was accomplished under these goals?
Technical Objective 1: Optimize heat transfer performance verified through Computational Fluid Dynamics (CFD) models and laboratory testing Research began with the development of mathematical models for the Solar Collector, Fluid Circulation System and Heat Exchanger. Each model describes the physics of the sub-system and was optimized, and then combined to calculate energy efficiency, heat delivery and rate of ice thaw under various atmospheric conditions. Results from modeling answered design questions addressed in the proposal, and led to the development of a component library. It includes manufacturer’s component specifications and is accompanied by a features-and-benefits comparison and cost-to-benefit analysis. The library provided the information needed to select components which then enabled the creation of solid models for each of the subsystems and the overall SSTH unit. Technical Objective 2: SSTH prototypes fabricated Wind and ice loads for SSTH were calculated in accordance with the AASHTO “Standard Specifications for Structural Supports for Highway Signs, Luminaires, and Traffic Signals”. Solid models were used to create FEA models of structural components. AASHTO extreme wind and ice loads were applied to the models and stresses, strains and deflections were calculated. Strength analyses were also performed for the heat exchanger housing since it resides in the bottom of the stock tank and is susceptible to livestock tampering or standing on the housing. Solid models and engineering drawings were created for prototype fabrication. One prototype trailer frame and two heat exchanger assemblies were fabricated. The prototype was assembled and installed. Technical Objective 3: Verify de-icing performance and equipment durability by field testing two prototypes through an entire winter season Test protocols were developed, and sensors and data acquisition equipment selected, installed, configured and calibrated. Four thermocouples were installed at the solar collector inlet and outlet and the heat exchanger inlet and outlet and a volumetric flow rate sensor was installed on the return line before the pump station. Data from thermocouples and a flow sensor are used to calculate the heat transfer rate from the solar collector, to the heat exchanger and the heat loss to the atmosphere. Three thermocouples were installed in the stock tank. The first thermocouple measures water temperature inside the heat exchanger, the second measures water temperature above the heat exchanger and the third measures air temperature above the water surface. Meteorological measurements include: air temperature, wind speed, barometric pressure and insolation. All field test data is acquired and stored locally on a datalogger with a wireless connection used for periodic data collection. Custom software is used to correlate heat production, weather conditions and melted ice and to present test results. Field testing commenced Spring 2014 and will continue through Spring 2015, to include a complete winter season. Technical Objective 4: Manufacture-ready design and prototypes to prepare for Phase III commercialization During assembly and field testing of the first prototype, design weaknesses were identified. First, several leaks in the working fluid circulation loop developed that required the leak to be repaired and the working fluid to be refilled, pressurized and entrained air removed. Second, the circulation pump experienced two failures causing thermal stall. Addressing these issues, potential design improvements were investigated, including: (1) tubing and fittings that are less prone to leaking, (2) repositioning the expansion tank to better handle thermal stall, (3) reducing operating pressure and selecting a relief valve with a lower pressure set point, and (4) expanding the role of PV in the system. Incorporating design improvements, a second SSTH prototype was designed, modeled and specified. The second prototype is being assembled and installed. Remaining project objectives will be satisfied when in situ testing is concluded with successful results and a manufacture-ready design is completed.
Publications
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Progress 09/01/12 to 08/31/13
Outputs
Target Audience: The target audience for the Solar Stock Tank Heater (SSTH) includes consumers who need surface ice to be melted. End-users located in areas where grid provided electricity is unavailable, inaccessible or cost-prohibitive make up the initial audience, along with consumers who choose to practice sustainability. This includes ranchers with livestock watering tanks in remote pastures, rural facilities with ice-covered walkways and construction companies operating in remote areas that need to thaw ground or warm work area flooring. In collaboration with the University of Wyoming College of Business, College of Agriculture and Natural Resources, and Cooperative Extension Service, regional agricultural product retailers and wholesale distributors, and U.S. ag-equipment manufacturers were contacted and provided detailed information about the SSTH. Construction companies building roads in remote locations were also contacted, along with individual ranchers, rural homeowners and recreational cabin owners. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals? Tasks to accomplish remaining goals: 1. Fabricate prototype 2. Install prototype at test site 3. Test, collect and analyze data 4. Modify design and prototype as required
Impacts
What was accomplished under these goals?
Water is critical to grazing animals. For example, cattle require between 3 to 15 gallons of water per head per day through the winter months, and will typically return to a water source to drink at least twice a day. To maintain a healthy herd, water must be available at these times, year-round. If the electricity grid is available, electric heaters are typically used to prevent stock tanks from freezing; and these heaters cost approximately $100 per month to operate. In situations where ranch pastures are far from the grid, the cost of extending the grid can be $10,000 to $40,000 per mile. An alternative product is a propane heater that requires regular cylinder change-outs and is subject to the fluctuating cost of fossil fuels. If a de-icing product is not used, ice must be manually chopped and removed to open water for livestock. Z4 Energy Systems, LLC is developing a reliable, cost-effective Solar Stock Tank Heater (SSTH) that uses solar energy to maintain open water in freezing weather. The overall objective is a fully tested and ready-to-manufacture SSTH system. Thermodynamic modeling of the SSTH is complete and the sizing and design of the evacuated tube (1) Solar Collector, (2) Heat Transfer System and (3) Heater Coil have been matched and optimized to meet the project objectives. Specifications and component selections are finalized; plans for fabrication are complete; and prototype components have been purchased. Three manufacturers provided cost estimates for prototype and production fabrication runs. After consulting with manufacturers, Z4 modified plans to better integrate with manufacturing processes and reduce cost. Remaining project objectives will be satisfied when prototypes are fabricated, in situ testing is concluded with successful results and a manufacture-ready design is completed. Technical Objective 1: Optimize heat transfer performance verified through Computational Fluid Dynamics (CFD) models and laboratory testing Solar Collector - Evacuated tube solar collector performance was obtained from the Solar Rating and Certification Corporation (SRCC) industry-standard database that includes heat collecting performance for commercially-available solar collectors. Daily heat collected and heat loss were calculated for a range of average temperatures and wind speeds. A solar collector was selected based on modeling results and a cost benefit analysis. Heat Transfer System – Thermodynamics modeling determined the effect on heat transfer from: circulation fluid flow rate, state of the flow (laminar or turbulent) and geometry of the tubing. A circulation pump was sized to provide optimum fluid flow rates when powered directly by a photo voltaic panel. Heater Coil - For optimum performance, the greatest amount of heat from the collector must be transferred into the water rather than lost to the atmosphere or returned to the collector. The Heater Coil design (taking into account matching the heat transfer rate, cost and complexity) is critical to SSTH success. Computational Fluid Dynamics (CFD) analyses determined the working fluid velocity, temperature and heat transfer rate. The CFD model was run for varied: (1) fluid inlet velocities (representing circulation pump volumetric flow rates), (2) turbulence models, (3) fluid properties (representing water and propylene glycol mixture percentages) and (4) copper pipe sizes. The fluid model was then combined with steady-state heat transfer to create a multi-physics finite element model. The final Heater Coil design was determined by matching the total heat transfer rate to a range of possible solar heat collection rates (taking into account material costs and pressure losses as a function of pipe size). Technical Objective 2: SSTH prototypes fabricated Z4 specified and selected components for the SSTH prototype. Major components include: (1) frame assembly; (2) trailer axle; (3) pumping station; (4) working fluid expansion tank; (5) photo-voltaic panel; (6) copper tubing for working fluid; (7) air pump; (8) heat exchanger housing; (9) heat exchanger coil and (10) the required fittings and connectors. Results from modeling answered design questions addressed in the proposal, and led to the development of a component library. It includes manufacturer’s component specifications and is accompanied by a features-and-benefits comparison and cost-to-benefit analysis. The library provided the information needed to select components which then enabled the creation of solid models for each of the subsystems and the overall SSTH unit. Three potential manufacturers have reviewed the models and provided initial time and cost quotes. Technical Objective 3: Verify de-icing performance and equipment durability by field testing two prototypes through an entire winter Test protocols are currently being developed, and sensors and data acquisition equipment selected. A portion of the test sensors and equipment has been purchased, set up and calibrated, and portions of the data collection software have been tested. Pressure, temperature and flow sensors monitor the efficiency of the Fluid Circulation and Heat Exchanger Systems; meteorological instrumentation (including temperature, barometric pressure, humidity, and wind speed and wind direction) logs atmospheric conditions; and site cameras document the rate of ice melt. Custom software will be developed to correlate heat production, weather conditions and melted ice. Technical Objective 4: Manufacture-ready design and prototypes to prepare for Phase III commercialization. Z4 contracted Manufacturing-Works, a Wyoming manufacturing assistance organization, to create solid models, drawings, and cut-sheets for the SSTH frame assembly. Z4 provided specifications and component selections for the frame assembly and reviewed the manufacturing models and documents created by Manufacturing-Works.
Publications
- Type:
Websites
Status:
Published
Year Published:
2013
Citation:
http://z4energy.com/Tank_DeIcer.html
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