P15484 Solar Assisted Essential Oil Distiller

P15484 – Solar Assisted Essential Oil Distiller

System Level Design Pre-Read

October 2, 2014

Manual Solar Tracking Concept Elimination

Figure 1: Oil Yield Requirements to Break Even

Industry standard oil yields range from 0.3%-2%. If solar tracking system were performed manually the distiller would have to produce oil at a yield rate much higher than industry standard.

Heat Source Concept Analysis

The team collected all criteria the customer might be interested in:

1. % of solar/renewable energy

The sun was assumed to be sufficiently intense 6 hours per day. For the 48 hour cycle this means 25% of the cycle has intense sunlight, 50% for the 2, 12 hour session cycle.

2. Initial cost

Benchmarked products were used to estimate the heating sub-system cost. A cost per Watt was calculated so that the cost could be scaled to the necessary Wattage. For some concepts, a best fit line on benchmarked products was used to determine this cost per Watt. Example:

3. Operating cost

a. Gas (propane) required

All energy required to boil water that is not supplied by the sun will be supplied by propane.

b. Labor cost

Labor was based off a rate of $6 per 8 hour day. Concepts requiring propane were assumed to require 10 minutes of labor while concepts requiring manual tracking were assumed to require 1 hour of labor per cycle (see known values and assumptions).

4. Hypothetical payback period

It is expected that a working system will be purchased by grants and thus will not need to be paid back. However, the payback period provides a basis for comparison between concepts.

5. Annual savings vs just propane

The cost to operate the concept was subtracted from the cost of running the system on only propane, which acts as a datum for this analysis.

No quantitative priority was given to any of the criteria.

1, 48 hour session – 25% intense sunlight – 111W Required

2, 12 hour sessions – 50% intense sunlight – 222W Required

Photovoltaic / Evac Tube / Parabolic Reflector / Parabolic Reflector w/ Tracker / Flat Plate / Solar Trough / Solar Trough w/ Tracker / Water Lens / Fresnel Lens / Fresnel Lens w/ Tracker / Propane
Percent renewable* / 100% / 50% / 25% / 50% / 50% / 50% / 15% / 50% / 50% / 50% / 50% / 50% / 0%
Percent from propane* / 0% / 50% / 75% / 50% / 50% / 50% / 85% / 50% / 50% / 50% / 50% / 50% / 100%
Initital cost (not including propane components) / $1,500 / $647 / $517 / $395 / $ 80 / $300 / $910 / $132 / $332 / $270 / $237 / $316 / $ -
Gallons of propane/cycle / 0.000 / 0.109 / 0.163 / 0.109 / 0.109 / 0.109 / 0.185 / 0.109 / 0.109 / 0.109 / 0.109 / 0.109 / 0.217
Labor hours required/cycle / 0 / 0.167 / 1.167 / 0.167 / 1.167 / 0.167 / 0.167 / 1.167 / 1.167 / 2.167 / 1.167 / 0.167 / 0
Payback period (yrs) / 8.12 / 8.43 / NEVER / 5.15 / NEVER / 3.91 / 72.15 / NEVER / NEVER / NEVER / NEVER / 4.12 / 0.00
Payback period (yrs, assuming gas is free) / 8.12 / 3.85 / 7.46 / 2.35 / 1.15 / 1.78 / 5.41 / 1.91 / 4.79 / NEVER / 3.42 / 1.88 / 0.00
Annual savings vs propane / $183.12 / $75.03 / $(69.75) / $75.03 / $(23.97) / $75.03 / $10.94 / $(23.97) / $ (23.97) / $(122.97) / $(23.97) / $75.03 / $(0.00)
Known values & assumptions / Comments / notes
Total Energy Req (MJ): / 19.3
Propane Cost per Gallon: / $6.38 / $25/tank at approx 4.7 gal/tank
Distillation cycles per year: / 132 / 4 months of prime season, 120 days, 60 distillations + 60% in the slower season, 8 months, 72 distillations
Labor rate in Haiti ($/hour): / $0.75 / Assume $6 / day
Oil yield: / 2%
Oil yield per cycle ($): / $1.40 / Processing 1 lb of plant material at 1% yield, vetiver oil sale price = $70/lb -> $0.70 per cycle
Energy per gallon of propane (MJ): / 88.80 / http://www.extension.iastate.edu/agdm/wholefarm/html/c6-87.html
100% propane annual cost ($): / 183.12 / 19.3MJ per cycle / 88.8MJ/gal = 0.217gal per cycle .217gal/cycle x $6.38/gal x 132 cycles = $183.04
Labor hours for tracking + propane: / 1.17 / 5 minutes to adjust tracking each half hour for 6 hours per day + 5 minutes to turn propane on&off 2 times = 70 minutes
Labor hours for just propane: / 0.17 / 5 minutes to turn propane on&off 2 times = 10 minutes
Initial cost of propane: / $90.00 / $30 tank + $60 burner & hose

Morphological Analysis Table

System Level Alternatives