The purpose of the project is to create a miniature version of a greenhouse for use in any automotive vehicles. To successfully execute this design, some experiments must be created and conducted to study the carbon dioxide and oxygen levels in the English ivy, a mechanism must be devised to allow for easy flow of gases to the plants, and the miniature greenhouse must be made to the vehicle’s and the plant’s convenience.
Creating some experiments to test how much carbon dioxide is converted to oxygen by the English ivy over a period of time would give an estimate of the impact that this design is having on air quality. It would also indicate how efficient the plant is at its photosynthetic process, and whether this plant is the best one for converting carbon dioxide to oxygen. Constructing the mechanism and the miniature greenhouse itself would provide a prototype of the intended design and would be useful in running tests to gather data on the practicality and the functionality of such a device.
Once these tasks have been completed, a model should be available that would display the workings of the miniature greenhouse based on the data collected using the experiments and and the tests done on the prototype.
3.1 Data on the USA 2013 Jeep Wrangler 4WD
For this project, all the data collected will be specific to the vehicle because many
factors that are tested for are dependent on the specific vehicle’s emissions. As seen in Figure 2, the car that will be used is the USA 2013 Jeep Wrangler 4WD with 3.6 Manual (M6) Gasoline [6]. Based on this make and model, the carbon footprint of the car will be determined using a model created to calculate that value to see how much carbon dioxide is being released into the atmosphere by this one vehicle. The calculation will also help deduce approximately how much oxygen will be released into the atmosphere after the conversion is complete.
Figure 3. USA 2013 Jeep Wrangler 4WD
Measurements of the width of the car will also have to be taken because the miniature
greenhouse will be spanning the width of the bumper of the car. The wider the greenhouse, the less it would interfere with the trunk of the car. The standard width of a 2013 Jeep Wrangler 4WD is 73.7” [7], but for this project, the prototype will be scaled down to represent all the elements of the greenhouse in a smaller form.
The parameter used when doing all calculations and experiments based on the jeep is keeping the car idle for ten minutes. This parameter will set the time span for any tests
and would prove the usefulness of the design, because many cars run on idle constantly, so converting carbon dioxide to oxygen while doing that would be very beneficial to the environment.
3.2 Data on the English Ivy
Some research was done to decide on the ideal plant for the miniature greenhouse. The plants that were considered were the spider plant, the english ivy, and the bamboo palm. Out of the three listed, the english ivy (Figure 3) is the easiest to access nationally and the one that requires the least maintenance, which would be an important factor for potential buyers.
Figure 4. English Ivy (Hedera helix L.)
A lot of research focused on the maintenance of the plant, in terms of the environment that it would most thrive in. The english ivy is a plant that cannot be directly exposed to the sunlight and it is also a plant that grows best in well-drained and fertile soil. The soil should ideally be around a pH of 7, which can be artificially created to an extent by adding hydrated lime or sulfur to increase the alkalinity. Generally, the best type of soil for any of plant would be a rich, sandy loam (a mixture of sand, silt, and clay). The english ivy will also need to be watered everyday because its soil needs to be moist. All these criteria will affect the outcome of the miniature greenhouse, in terms of the material used to create it and what would go inside it.
An important statistic that could not be ascertained from the research is the efficiency of the conversion of carbon dioxide to oxygen. Every plant’s photosynthetic process varies based on the plant’s physiology as well as its environmental factors. To receive the maximum conversion rate possible for the designated ten-minute time frame, the plant’s photosynthetic process must be studied. In order to derive this estimate of the rate, an experiment will be done measuring the photosynthetic rate through the uptake of carbon dioxide. The english ivy alone, without the roots or soil, will be placed into a bag (Figure 4) along with a carbon dioxide monitor (Figure 5), which will read the amount of carbon dioxide that is released by the plant in that closed environment [8]. There will not be a lot of carbon dioxide to fix because of the closed environment but this value could be used to determine how much carbon dioxide is being converted over a longer period of time [8].
Figure 5. Plant in a plastic bag Figure 6. Carbon dioxide meter
The concentration of carbon dioxide that can be handled by the plants and the amount of plants that should be placed in the greenhouse must also be established. However, these statistics will have to be found through experimentation. Exposing the english ivy to the car exhaust at different distances from the exhaust will “dilute” the gases in the air, allowing the concentration of the gases that is needed to be determined. Also, the more plants that are available in the miniature greenhouse, the more photosynthesis can occur, so the number of english ivy plants required would be dependent on the area that can be covered in the miniature greenhouse.
Another key factor is that other gases besides carbon dioxide are released from the car exhaust, and this is also somewhat dependent on the car chosen. The jeep will emit methane, nitrous oxide, hydrofluorocarbons, and carbon monoxide as well. It was necessary to determine that these gases are not harmful to the english ivy in any concentration because the plants would not be able to withstand the emissions at all then. Research indicated that the english ivy could be exposed to these gases without causing damage [9]so this was another reason for choosing this plant.
3.3 Construction of the Greenhouse and the Mechanism
The first aspect of creating the miniature greenhouse is identifying the materials needed. Most greenhouses are made of glass, fiberglass, double-wall plastic, or film plastic [9]. The best material for the covering seems to be the fiberglass because it is very strong, lightweight, and traps the heat in well, making it ideal for vehicles. As long as a quality grade fiberglass is found, such as Tedlar-coated fiberglass, it could last for 15 to 20 years [10]. Since the english ivy thrives more in an environment not directly exposed to sunlight, part of the greenhouse can be tinted as well. The frame of the greenhouse must also be considered. The most applicable frame for such a design is the rigid frame--usually made of metals and/or wood--because it does not require too much material but is a very sturdy frame so long as the foundation is strong [10].
The miniature greenhouse will have several features built in to manage the gases and the maintain the plants. As indicated in Figure 6, the front of the greenhouse can be opened via the handle. This is there so the plants can be cared for everyday and they are easy to access at all times. This is also convenient for cleaning the greenhouse from the inside because the car exhaust gases can leave residue on the fiberglass.
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| Figure 7. Miniature Greenhouse |
The other features in the miniature greenhouse are the filtering mechanisms. There are two filtering mechanisms in this design: one is on top of one half of the greenhouse, to let out the gases in case there is too much of a build-up (Figure 7), and the other is inside and it splits the area of the greenhouse in half (Figure 6). The filtering mechanism located on top will monitored by the carbon dioxide meter. It will read the carbon dioxide levels and if the value is dangerously high, then a mechanism will be triggered to open up the glass on top. This would release some of the gases into the air to avoid any harmful reactions. The other mechanism inside the greenhouse splits the area of the plants and the gases in half and there are open holes on that partition to let the carbon dioxide go through to the plants. The carbon dioxide reaches the plants through the partition, gets converted to oxygen, and then is released to the atmosphere through an opening located on the left side of the greenhouse (Figure 6).
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| Figure 8. Filtering system from the top |
The final technical challenge with regards to the greenhouse and the mechanism is getting the greenhouse attached to the back of the car. A mechanism similar to a car hitch can be installed, and the base of the hitch will span approximately 70” (very close to the full width of the Jeep Wrangler 4WD). This flat base will have the greenhouse drilled to it so that the greenhouse is sturdy and will be close enough to the muffler of the car to get the gases into the system to complete photosynthesis (Figure 8). The hitch will be made of a lightweight yet sturdy metal, so it can support the weight of the miniature greenhouse. This will allow for easy access to the miniature greenhouse and will be safer than actually attaching it to the car.
Figure 9. Miniature greenhouse’s attachment to the car
