Grantee Research Project Results
Final Report: Biomass Greenhouse-heating systems to extend growing seasons for resource-limited farmers
EPA Grant Number: SU835939Title: Biomass Greenhouse-heating systems to extend growing seasons for resource-limited farmers
Investigators: Yu, Ok-Youn , Domermuth, David , Houser, James , Farrell, Jeremy , Arnold, Alex , Davis, Chelsea , Franco, Pedro , Neff, Eric , Schoonover, Christopher , Smith, Alan , Sanborn, Jared , Febos, Barry , Atkinson, Mason , Mull, Henry , Linck, Jon , Miller, Gordon , Wells, Aaron , Holder, Jordan , Phillips, Jay , Anderson, Nathan , Beshears, Tyler , Joyner, Joshua , Roden, Elizabeth , Batzko, Gabbie , White, Harrison , Toy, Jamen , Houpe, Christian , Holmes, Anna Marie , O’Neal, Johnny , Bradshaw, Aaron , Gaines, Rachel , Gaines, Rachel , Cyzman, Amy , O’Neal, Johnny , Bradshaw, Aaron , Cyzman, Amy
Institution: Appalachian State University
EPA Project Officer: Page, Angela
Phase: II
Project Period: October 1, 2015 through September 30, 2017 (Extended to August 31, 2019)
Project Amount: $74,555
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2015) Recipients Lists
Research Category: Sustainable and Healthy Communities , P3 Awards , Pollution Prevention/Sustainable Development , P3 Challenge Area - Air Quality
Objective:
The purpose is to develop inexpensive and efficient biomass greenhouse heating technologies that provide affordable means to improve the food-growing capacities and standard of living for farmer communities in rural Appalachia while eliminating the use of fossil fuels. In order to realize the above vision, our team has completed the following objectives:
- Systems integration
- Farm gas cleaning and storage
- Farmer outreach
Summary/Accomplishments (Outputs/Outcomes):
Objective1: Systems Integration
Each heating technology has been integrated, tested, and refined at Nexus (refer to annual reports). In order to investigate accurate BTU usage during winter time, we disconnected all heat delivery pipes from heating sources to the thermal battery (TB) except propane water heater and solar thermal collector from December 2015 through Feb 2016. Then, we collected temperature data from five different locations: 1) inside TB, 2) pond, 3) hydroponics, 4) inside greenhouse ambient, and 5) outside greenhouse ambient as shown in Figure 1.
Figure 1. Temperature monitoring locations Nexus
Since the minimum pond temperature of 55 F is suggested for tilapia to survive, our target temperature for pond was above 65 F. We began with temperature setting at 80 F for TB, and monitored the pond temperature distribution in the last one week (12/24 to 12/31) of 2015. We figured out that the pond temperature kept above 70 F all the time during our monitoring period. With 80 F TB temperature, the pond kept above 60 F during January 2016 except for one outlier of January 26, when the power running pumps was out. In the same manner, hydroponics beds kept above 55 F. Inside temperature of the greenhouse kept above 30 F even with outside temperature recorded below 4 F (1/19). Table 1 shows a summary of average and minimum temperature data for each component.
The propane tank was refilled four times during this winter time, and the last refill (88.9 gallon) was made on 2/19/2016. Since a propane tank is usually filled up to the same point (i.e., 85% of the tank capacity), the amount of propane refilled indicates that how much propane was consumed since the previous refill date. Therefore, we assumed that 88.9 gallon of propane was consumed from 1/15/16 (the third refill date) to 2/19/16. Converting propane gallon to BTU (91,502 BTU/gallon of propane), we figured out 8,134,528 BTUs was consumed to keep the thermal battery at 80 F.
Using our modeling tool, we estimated 11,725,374 BTUs to heat the greenhouse with a conventional heating method (i.e., space heating) during 1/15/16 to 2/19/16. It indicates that we could save 31% of BTUs with our thermal battery (TB) plus aquaponics heat distribution as shown in Table 2.
Since the aquaponics bed temperature (i.e., root zone temperature) affects directly on plant growth, this data indicates that our system, storing heat at the thermal battery and distributing the heat via aquaponics, is more efficient to grow crops and save energy in cold season.
Objective 2: Farm Gas Cleaning and Storage
Figure 2. Homebiogas system at Nexus
We have been doing a lot of research on affordable small-scale anaerobic digestion (AD) systems using self-constructed digester bags or systems made from Intermediate Bulk Containers that are readily available and inexpensive and have made significant progress in terms of biogas cleaning (refer to annual reports). In addition, we have installed a unique small-scale biodigester to convert organic waste into cooking fuel and fertilizer inside the Nexus greenhouse as shown in Figure 2 and kept monitoring the performance of the digester. We found that adding biochar (i.e., biochar combined anaerobic digestion) enhances biogas production. We will continue working to determine effectiveness (biogas potential) of biochar combined anaerobic digestion with biochar from various sources in combination with various agricultural waste streams, such as manure, food waste, cheese processing waste (whey) and any other potential biomass waste streams on the cooperating farms. However, we have not been able to go forward with our desire to test compression of gas due to difficulties in finding a skilled student.
Objective 3: Farmer Outreach
Nexus research team has begun collaboration with two working farms in Watauga County. Springhouse Farm in Vilas and Against the Grain (ATG) Farm in Zionville can be characterized as small farms that intensively manage less than 20 acres. They primarily sell to community supported agriculture, local restaurants, regional distributors, and directly at farmer’s markets. These two farms are diversified and practice primarily organic production methods. They both rely on considerable amounts of human labor for management and harvest, while mechanization is reserved for cultivation and land clearing. Both farms are deeply interested in staying abreast to new techniques and have a spirit to try new things and potentially incorporate them into their farming practice.
Springhouse Farm has a 20 ft by 30 ft high-tunnel greenhouse and there are four growing benches and one germination bench inside. We installed solar collector, biochar kiln, food dehydrator, and root zone heating system for the greenhouse. The collected heat from the solar collector and the biochar kiln is stored in a 40 gallon propane water heater. The collected heat is radiated to the soil on the benches through ¼” PE tubing installed under the growing tables. Water-Propylene mixture (50:50) is used for heat transfer fluid (Figure 3).
ATG farm has a 30 ft by 16 ft passive greenhouse built in 2016. The pilot system we installed at ATG includes a biochar kiln, solar thermal collectors, a food dehydrator, a water storage (i.e., thermal battery), and vertical germination racks with root zone heating system. The heat collected from the biochar kiln and solar collectors is stored in the thermal battery. The heated water is radiated to the passive greenhouse and to the germination pots sitting on vertical racks over the thermal battery at night. The root zone heating system at ATG has four racks over the thermal battery and there is ¼” EPDM tubing installed under the each rack. Each rack has 10 loops of tubing and a ball valve installed to isolate the rack if not used. During the warm season when heating is not needed, the collected heat will be used to dry food in the food dehydrator. Dried food such as dried apples and sun-dried tomatoes is a good way of food preservation, and can be another source of income for farmers (Figure 4).
Figure 3. System layout at Springhouse Figure 4. System layout at ATG farm
In addition, we hosted two workshops. The first workjshop (October 21st, 2015) was part of the third annual National Bioenergy Day event, and the first-ever open house of the project at Nexus. We were pleased to have more than 70 people attend including sponsors, Appstate staff and students, farms and organizations from the local area as well as other areas. The guided site tours provided an opportunity to learn about on-farm biomass energy and its benefits. The event was a great success and fulfilled its role to introduce the biomass energy research to the community and promote interest in the project. We gathered valuable feedback from the extension and local farmers, which will influence future research. We look forward to participating in this annual event to engage with our community and share the progress of the bioenergy research. We held the second workshop (April 29th, 2018) in association with Blue Ridge Women in Agriculture (BRWIA). BRWIA is a group in the High Country dedicated to improving local farming and building a vibrant local food system. The workshop we hosted by Springhouse and Against the Grain farms, two of our partner farms, focusing on root-zone greenhouse heating, biochar production, and solar and biomass process energy for heating and crop dehydrating (Figures 5 and 6).
Figure 5. Composting explanation during the open house
Figure 6. Graduate student Barry Febos presenting on Biochar kiln at Springhouse farm
Conclusions:
After testing various biomass/renewable heating technologies at Nexus, we built two integrated heating systems at our cooperating farms. The root zone heating system installed at Springhouse was monitored from February 15, 2018 through June 12, 2018. Amy Fielder, owner of the farm mentioned that she could not notice any slower germination with our system compared to previous years. In addition, Amy got a better or equal result for crop growth with 55% of propane saving compared to 2017 (207.8 gallon in 2017 vs 93 gallon in 2018). February through May in 2018 has higher number of heating degree days (HDD) compared to 2017. Springhouse Farm used 30% less propane in 2019 with improved bench covers, even though HDD were only 100 less than the previous year. When the root zone heating system at ATG Farm was running, air temperature inside the vertical rack cover exceeded greenhouse air temperature by as much as 15°F. Our project has put in place a foundation for supporting student and community involvement. With its low annual operating costs and close proximity to the greater community, Nexus is poised to create a reliable and ready environment for ongoing collaboration with farmers, continued research and study for university students, and greater community involvement in local food, energy, and environmental issues. We will keep the project moving forward by collaborating with more local farmers.
Journal Articles on this Report : 1 Displayed | Download in RIS Format
Other project views: | All 11 publications | 1 publications in selected types | All 1 journal articles |
---|
Type | Citation | ||
---|---|---|---|
|
Yu O-Y, Harper M, Hoepfl M, Domermuth D. Characterization of biochar and its effects on the water holding capacity of loamy sand soil: comparison of hemlock biochar and switchblade grass biochar characteristics. Environmental Progress and Sustainable Energy 2017;36(5):1474-1479. |
SU835939 (2016) SU835939 (2017) SU835939 (Final) |
Exit Exit |
Supplemental Keywords:
biomass, greenhouse heating, renewable energy, season extension, biochar, anaerobic digestionRelevant Websites:
Appalachian Energy Center Exit
Progress and Final Reports:
Original AbstractP3 Phase I:
Biomass Greenhouse-Heating Systems to Extend Growing Seasons for Resource-Limited Farmers | Final ReportThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
- 2018 Progress Report
- 2017 Progress Report
- 2016 Progress Report
- Original Abstract
- P3 Phase I | Final Report
1 journal articles for this project