Ichigo Takikawa, Zoe Johnson, and Tanya Kornilovich. What The Data Shows
What The Data Shows
The rapeseed produced the highest total energy, while the poplar produced the least. This data was then compared to previous studies (Lemus, 2005, Cocco, 2007) detailing the energy that each plant yields for biofuel. The calculation came up with a correlation coefficient of .84, that suggests that the total energy amount of a plant would approximately predict the biofuel yield, but would not be very accurate, requiring more testing to verify the correlation. This can, however, be used for comparison purposes if the energy difference is significant.
How This Can Be Used
Our hypothesis stated that if the three plants are tested using a calorimeter, then the Brassica napus (rapeseed) will yield the highest amount of energy because it contains a high ratio of vegetable oil and has been widely used for the production of biofuel. It also predicted that there would be a high correlation between the total energy and the biofuel yield of the plants.
The hypothesis correctly predicted that rapeseed would yeild the most, but it does not correlate with previous studies. Several reasons could have attributed to this, including that rapeseed has a ''cake'' surrounding the oil-based part of the plant, which produces a great amount of energy, which may have been displayed in the data. In the process of producing biofuel, only the lipids of the plants are used. In switchgrass, there is little additional material; so most of the switchgrass material is used in the manufacturing of biofuel. This cake, therefore, may have interfered with the data and did not correlate with the biofuel.
Further investigations to improve this experiment would include the formation of plants into pellet form, which would make the plants more flame sustaining, as examining the energy produced by the lipids of the plants. The data produced by this experiment supports that a correlation for comparison purposes exists between the total caloric energies and biofuel energies, providing extreme benefit in the production of alternative energy sources.
Why Does This Correlation Matter?
Plants such as Brassica napus (rapeseed), Panicum virgatum (switchgrass),and Populus angustifolia (poplar) are in high demand as a renewable energy source. The purpose of this experiment is to determine if there is a direct correlation between the total amounts of energy the dried, ground plant material produces and the amount of energy the plant produces for biofuel. With this correlation known, a small amount of the plant could be burned and tested for its total energy rather than biofuel content, and this may determine its usage for creating biofuel much more quickly, and for less money. Utilizing this correlation will result in sufficient decrease in spending and will improve the quality of alternative energy sources.
What We Did
A calorimeter was constructed to measure the total amount of energy that each plant releases. The calorimeter was built with two metal cans. The smaller metal can was submerged into the larger can, which was then filled with water. These two cans were placed inside of a Styrofoam box and surrounded with newspaper so that the heat released by the combustion of the plants was well insulated (Photo 2). The plants were dried in a drying oven at 35 degrees Celsius, ground up into powdered material, and combusted inside the container. In order to successfully combust the plant material, the calorimeter was channeled with compressed air, which continually ran into the container (Photo 5). The plants were burned four times at 0.5 grams per trial (Photo 4). The amount of heat produced was calculated by the temperature difference in the water using the LoggerPro (Photo 6), and the laws of thermodynamics were used to calculate the exact energy of the plants.
Above: Tanya Kornilovich and Zoe Johnson prepare the calorimeter for experimentation. Newspaper was used for extra insulation.
Figure 1: The plants were combusted inside the calorimeter to determine its total energy amount. The difference in temperature of the water was used to calculate the energy.
Correlation Coefficient for the Biofuel Yield and the Total energy amount of Each Plant
Photo 1: Ichigo Takikawa uses the band saw to cut pieces for the box that will insulate the calorimeter.
Photo 2: Using foam adhesive, Zoe Johnson constructs the insulation box.
Figure 2: The total energy amount was calculated to the plants’ biofuel yield from previous scientific studies. The correlation between these data sets produced the correlation coefficient of .84, which is not high enough to show that a correlation existed between the two data sets.
Photo 5: The calorimeter was connected to the LoggerPro temperature probe and the tube shown channeled compressed air throughout the system to keep the flame going inside.
Photo 6: The temperature of the calorimeter was recorded every 5 seconds by the LoggerPro temperature probe. This device was connected to a laptop with the LoggerPro program, which kept track of the data.
Photo 3: Tanya Kornilovich cuts plants in preparation for grinding and drying them.
Photo 4: Zoe Johnson measures the dried plants for testing.
All photos taken by Ichigo Takikawa and Zoe Johnson
Revised: 9 August 2014