Callahan Engineering is pleased to announce the completion of a
report on a 2 year study done under contract with UVM Extension with 14 greenhouse growers exploring the use of renewable fuels for greenhouse heating with funding from the
High Meadows Fund.
From the report:
“Greenhouse production in Vermont covers 2 million ft2 and produces $19 million in crops, of which about $4 million are vegetables. We have calculated that the state uses 296,000 gallons of propane and 59,000 gallons of fuel oil each year to heat greenhouses. This equates to a cost of $768,000/yr and 2,458 tons CO2/yr – roughly equivalent to 6.2 million automobile miles.
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I’m often asked how much energy can be stored in hot water. The ability for any material to serve as a thermal battery depends on its heat capacity (e.g. units of BTU/lbm/degF), the mass of the material (e.g. units of lbm), and the temperature change imposed (e.g. raising water from 50 degF to 180 degF). For most of the clients I work with, hot water is a simple and effect thermal storage media. I developed
this chart to enable people (including me) to quickly and graphically determine how much water (gallons) would be required to cover a certain heat load (BTU/hr) without any explicit math. I hope it is useful for you.
Callahan Engineering conducted a
feasibility study of mobile oilseed processing and biodiesel production for the
Vermont Sustainable Jobs Fund and the
High Meadows Fund.
Vermont oilseed production in support of food, feed and fuel markets on Vermont farms shows great promise. One challenge is the distribution of necessary equipment to process oilseeds into more useful forms; meal, oil and biodiesel. Most farmers will not assume the risk of both producing oilseed crops and attempting to convert them to oil and meal. Mobile processors are one way to enable this fledgling agricultural industry.
A summary of the components involved in oilseed processing.
With funding from the USDA’s Sustainable Agriculture Research and Education (
SARE) program the feasibility of farm-based biodiesel production in Washington County has been evaluated. The focus of
this study was to determine if Washington County farms could support production of sufficient biodiesel to self-fuel their operations. This study was not intended to explore the possibility of using Washington County farmland to support the fueling of on-road or passenger vehicles or home heating equipment and does not explore ethanol production. Therefore, this study assessed farm based biodiesel production as a cost avoidance and energy security initiative.
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Callahan Engineering assisted in the design, specification and performance assessment of a
solar augmented grain drier for
State Line Biofuels. This project was funded by the Vermont Agency of Agriculture, Food & Markets under the Renewable Energy for Agriculture Grants Program and by the Vermont Sustainable Jobs Fund (VSJF).
Solar Grain Drier at State Line Farm (Shaftsbury, VT)
An anaerobic digester has been in operation at Freund’s Farm for 9 years and is used only for heat (i.e. no electric power output). Callahan Engineering worked with Freund’s Farm under a
SARE-NE grant (ONE06-053) to track its operation and better understand its performance. The digester performance was measured nearly every day for 16 months, providing a database for review and analysis.
Based on the information gathered the team was able to determine boiler burn rate (202-313 kBTU/hr), gas quality (60% CH4), digester system efficiency (55%), digester system reliability & availability (82% & 95% respectively), and boiler combustion efficiency (70-90%). The team also identified possible causes of foaming which has been an issue for the digester operation. Several lessons learned have also been documented and areas for further study are proposed.
Farm Schematic Showing Freund's Farm Digester Integration.
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