Experimental Procedure

This page is a how-to guide to construct our calorimeter design, carry out our experiment, and calculate the energy density of a sample of biodiesel. While it is optimized for biodiesel, this process can be used to measure the energy density of most fuels.

Materials
Materials:
2 metal cans (such as a soup can)

several feet of string or wick

1 small glass container with a small opening radius
1 thermometer

1 Small knife 

1 Sealed styrofoam container(should be able to fit both metal cans stacked on top of each other, thicker styrofoam will yield better results)

At least 10 ml of biodiesel (this amount will vary depending on size of the glass container)

Construction

1. Braid the string/wick. Instructions are displayed in the video below. Create at least three braided wicks.

2. Cut two rectangular openings in can #1, shown in (b). Additionally, cut off the bottom of the can, shown in (c). Keep both parts.

3. Cut out a 4 cm x 6 cm square hole in the styrofoam container with the center adjacent to the level of the wick, shown in (d). You may also want to lay a layer of aluminum foil at the bottom of the styrofoam container to protect from spills. Direct contact with the biodiesel will melt the styrofoam (but very slowly).

4. Place the braided wicks into the glass container along with a measured mass of biodiesel to create a spirit burner. The biodiesel should reach at least half the height of the glass container. shown in (e).

5. Make sure the wicks are fully soaked with biodiesel from top to bottom. A suggested method is to submerge the wicks completely inside the biodiesel in the container. Make sure to have an apparatus, such as a paper clip, to pull the wicks out. 

6. Using duct tape, adhere the burner to the bottom cutout of can #1, shown in (f).
Place this in the center of the styrofoam container, as shown in (g).

  

7.Place the other part of can #1 on top of the bottom with the cutout of the styrafoam adjacent to the cutout of the can, shown in (h).

8. Measure a specific mass of water (such as 200 mL) and place it in can #2. The amount of water can vary but in our experiment, 200 mL was used. Place can #2 on top of can #1, shown in (i)

9. Place a thermometer in the water. 

10. Place can #2 on top of can #1. Seal container in all places except the intentionally cutout part. If the thermometer does not allow the lid to fit, cut out a small hole for the thermometer to fit snug into the hole. An example with the lid slightly open is shown in (j).

At this point, the calorimeter has been completely assembled.

Procedure

Once the calorimeter is completed, the following steps will allow one to measure the energy content of a sample of biodiesel.

1. Measure the initial temperature of water in the can. Make sure all materials are at room temperature. Make sure that the mass of the biodiesel and water are recorded.

2. Light the wick. This can be done with a long torch through the openings. However, if a long torch is not available, a shorter device, such as a match or lighter, can be used. For this, the biodiesel container must be taken out, lit, then placed back in quickly.

3. If the flame does not appear sufficient, add more wicks or increase the size of the hole in the styrofoam.

4. After about 10 minutes, blow out the flame, record the temperature of the water, measure the mass of the water, and measure the mass of the biodiesel. The measurements MUST be recorded as soon as possible to ensure the most accurate results.

5. Once all measurements have been recorded, the calculations can be done. It is advised to do the procedure multiple times and take an average to ensure the best results.

Calculations

1. Subtract the mass of the final biodiesel from the initial biodiesel to get the amount of biodiesel burned.

2. Subtract the final mass of water from the initial mass to get the amount of water evaporated. (water will evaporate even when not boiling).

3. Subtract the initial temperature from the final temperature. (All measurements should be in Celcius. If in Fahrenheit, use the following conversion equation to get temperature in Celsius: (°F  -  32)  x  (5/9) = °C).

4. Calculate the energy that was added to the water using:
E = s x m x dT

E = Joules
s = specific heat of water ~4.18 J/g
m= initial mass of water in grams
dT = change in Temperature

5.Calculate the energy from the evaporated water:
E = m x Hv

E = joules
m = mass of evaporated water in grams (initial - final)
Hv = Heat of vaporization of water ~2257 J/g

6. Add the energy values obtained in 5 and 6. Divide that sum by the mass of biodiesel burned and you obtain the value of energy density of the biodiesel in Joules per gram. The higher this number, the greater energy per amount of biodiesel.


Calculator
To make your calculations easier, just input your values into the labeled boxes and choose the energy unit you want!

Initial mass of the water (grams) =
Final mass of the water (grams) =
Initial temperature of the water (degrees Celsius) =
Final temperature of the water (degrees Celsius) =
Initial mass of the biodiesel (grams) =
Final mass of the biodiesel (grams) =

Calculate the energy in:

Energy from liquid water (Step 4 above):
Energy from evaporated water (Step 5 above):
Total Energy released:
Energy density:

It is important to note that this process is not 100% efficient. A small amount of heat is released into the other parts of the calorimeter and the air. While one could calculate the amount of energy absorbed by the spirit burner, cans, styrofoam container, and air, this still would not account for all the energy released due to the cutout opening allowing air to travel through, and the fact that the styrofoam is not 100% insulating. More importantly, it would detract from one of the main principles of the project: simplicity.