Tech Approach is how we will test the PCMs and why we are testing that way
Team Process is basically the rules for the teams and how conflicts will be handled
The Project Plan is a living document and needs modification during the course of the project. Therefore a mechanism for formally amending it is required. Specifically, the party requesting the change will write a brief description of the desired change, and all other parties will assess the impact on the project. These parties will respond, in writing, stating that there is no impact on performance, cost or schedule, or specify the anticipated impact
GROUP 3: 3 MEMBERS: TW,LF, WC
WRITE THE PAPER ON THE FOLLOWING #####DO ONLY NUMBER 2A,B,C,D AND NUMBER 3#####
1) Requirements and needs: a. Customer needs (a product, design, improvement) and requirements (including performance, accuracy, power, weight, thermal, environmental and safety requirements where applicable) as given are to be analyzed for conflicts and assigned priorities. Specifications will be developed for all requirements. b. Requirements derived from the design approach selected are to be included in this section. c. Both customer and derived requirements are to be addressed.
2) Task statements (TS), statement of work (SOW), work breakdown structure (WBS), responsibility assignment matrix (RACI) and team process guidelines:
a. TS and SOW: Describe tasks and specific activities to be performed. Do not forget relevant industry standards and regulations
b. WBS: list individual specific activities in a hierarchical structure
c. RACI: Hours (estimate) and person for each task in a chart.
d. Team process guidelines: How to deal with time conflict between team members? How to maintain smooth communication? Time management, individually and as a group? Confrontation management? Schedule change authorization?
3) Technical approaches: how and why for the project
4) Schedule: a. Show all tasks with start and end dates, including reviews, presentations, and report dates. b. Create and maintain effort logs (time sheets) on a daily basis. The effort logs would then be used to update the schedule on a regular basis to ensure that the project is on track. 5) Budget Present two budgets: one is for the cost of materials, and the other adds student labor cost at $12.75 per hour to the material cost based on the data from effort logs. 6) Risk analysis: Risk analysis will include the likelihood, potential impact, and mitigation strategy for three categories of risk: 1) technical performance risk, 2) schedule risk, and 3) cost risk
REVELANT MATERIALS – we met with our sponsor, to ask clarifying questions. He gave us some deliverables; biocompatible PCM that lowers the temperature of TEG and an encapsulation method for the PCM. Jones was unable to reveal past data that was collected using non-biocompatible PCMS on the TEG but he can provide us with some data of prototype testing. We also learned that we will want to multiple the specific heat of PCM by 1.5” to calculate the amount of energy that is released. One idea that was mentioned by Dr is to make many “patches” of this PCM that can be easily switched out once it becomes a liquid. Background: The proposed project aims to build a biocompatible Phase Change Material (PCM) to take heat away from a wearable device and serve as a self-regenerating power source. Thermoelectric generators (TEG) have shown promising results to meet the needs of current problems in wearable technology. One of the main problems is the need to take the device off in order to recharge it. A PCM will be able to retain and release energy in the form of heat, resulting in a device that can ultimately charge itself by utilizing body heat. The biocompatibility of this material will allow for safety from any burning or harming of the skin. The temperature requirement of the heat device is an average of 33 degrees Celsius, therefore the PCM used will fulfill this need as well. A design and creation of a material that holds a large enough temperature change in order to conduct enough electricity required to power the device will also be required. Ideally, the material’s phase change will fluently go back and forth between solid and liquid form in a closed system. To perform future testing of this PCM, we will use a hot plate set at ~35 degrees Celsius to simulate body temperature. Functionality: We are designing a Phase Change Material (PCM) that can sit on top of a thermal energy harvesting device which will have a temperature gradient that changes the overall temperature of this wearable device. The main function of this material is to take heat away from a thermoelectric source worn on a human that converts body heat into electricity. This electricity can then be used to power the device itself. Ultimately, we are looking to create a material that will be self-replenishing and work as a closed system to constantly maintain a large enough ΔT to provide enough electric energy to power the device. This material will need to go through a phase change of liquid ⇌ solid as it gains heat from the device to generate power and then loses heat once this power is used. As the temperature of the material increases, it will become more of a liquid while as the temperature decreases back to its “resting” temperature, the phase change will result back to a solid form. The functionality of this will be affected by the heat device’s ability to generate sufficient amounts of energy from body heat. The material we create will be placed on top of what is called a thermoelectric generator (heat device), also referred to as a TEG. Theoretically, a wearable TEG can generate up to 180 μWcm-2 (microwatts per centimeters squared). 1 Technical Performance: The technical performance of this phase change material will depend on several factors. Overall, the process of cooling is highly attractive as it involves high specific heat and high latent heat of fusion variables and requires only a small change in volume. Moreover, the biocompatibility of materials that will be used has known and manageable melting points. We also know both organic and inorganic PCMs are reliable even for repeated use. It is vital that the PCM melting point temperature must be below the temperature of the heat device. To help ensure this, we have methods for speeding up the process of thermal conductivity. One such method is the use of differently shaped fins that have a high thermal conductance, thus making for a faster conductance process. It is also important that the size of the material allows for enough heat rejection. To this end, the device calls for a compact design, and knowledge of how changes in the surface area affects heat retention and rejection will be critical. The structure of the material will also be taken into consideration. Research on a honeycomb structure and the use of fins has shown promising results for heat transfer.2 The flexibility of a PCM-based heat-sink will be crucial as it will be a part of a wearable device. Depending on the material we choose, a technique that allows for the PCM to be flexible while still contributing to the heat flux for power generation is essential.3 Energy: The technology of utilizing a phase change material for thermal energy storage uses 100% renewable energy.4 Latent heat from the body can be harvested, using a Thermoelectric Generator (TEG), to produce energy. The use of Phase Change Material, on the opposite side of the TEG, will cause a change in temperature across the system. This change in temperature is directly proportional to the amount of energy the TEG can produce. A simplified schematic of this can be found in Figure 1. As illustrated, the larger the change in temperature, the greater amount of energy is produced. Economics: The cost to make this material will depend on the biocompatible material we ultimately choose to utilize. As for the thermoelectric materials, they can be more costly depending on their makeup. A TEG that is made of Mg2Si0.6Sn0.4 is $4.04/kg, whereas one consisting of Bi0.52Sb1.48Te3 is $125/kg. The cost of varying fabrication methods including sputtering, etching, thermal evaporation, chemical deposition, and photolithography, can run high as well. This is in part due to the fact that they all utilize high temperatures and are complex processes that boost the overall price. However, on the other hand, the cost of PCMs is relatively low and very affordable.5 Environmental: The whole idea of utilizing waste heat, or body heat, for conversion into thermoelectric power, is rather revolutionary. It is one of the cleanest sources of energy on the market. One of the many advantages of using this form of energy is that there are zero emissions of harmful pollutants. Additionally, there are no chemical reactions with the outside environment. The thermoelectric generators usually last around 30 years, which is also an eco-friendly benefit as they will not have to be replaced often. Furthermore, the materials that are used for both the phase change material and heat device are reusable. However, these materials are rare, and research is currently being done to make the use of them more sustainable. 6 Health and Safety: Depending on the type of phase change material used, there is a range of health and safety concerns that vary in severity. The most common phase changes of PCMs are solid ⇌ liquid, solid ⇌ gas, and liquid ⇌ gas. To achieve the desired temperature change and electrical output, organic, inorganic, and eutectic phase change materials must be considered. All, however, come with both risks and benefits. Organic materials present the least amount of risk. The most common organic PCMs are types of paraffin, or straight-chain saturated hydrocarbons, with melting point temperatures ranging from 23℃elsius to 67℃elcius. These are considered non-toxic and harmless to the environment.7 Non-paraffins are the most researched organic PCM. They are also a very safe option and consist of fatty acids, which are easily produced from plant and animal oils.8 Inorganic PCMs are slightly more hazardous, as they contain slightly corrosive and toxic materials when they come in contact with certain metals. However, inorganic materials are a popular choice because they are physically and chemically stable in situations where the need for extremely low or high melting point temperatures is crucial. The most dangerous yet versatile PCMs are eutectics. These PCMs are man-made mixtures of multiple compounds that act as a single unit.9 This allows for extreme precision when determining the necessary melting and freezing point temperatures required for the largest swing in temperature change and energy production. However, it also allows for the possibility of human error and the mixing of two or more non-compatible compounds. This could result in harm to the user in the forms of rashes, burns, or the exposure to harmful off-gases, as well as damage to testing equipment via corrosion and/or melting. Legal: The ability to harvest the latent energy produced by the body is a highly desirable and heavily researched topic in science and engineering. There is very limited legal implication involved in this project as long as all research is properly documented and there are no patent infringements on the technology and PCMs being used to successfully fulfill the project’s end goals. However, with the growing popularity of wearable thermoelectric power generators, the use of this device will have to be approved by the FDA. The PCMs being used are not intended to come into direct contact with the user’s skin, yet FDA approval will ensure that any inadvertent contact with the PCM has been deemed safe to the user. Additionally, depending on the chosen PCM, clearance by the EPA and OSHA may be necessary to guarantee that all substances are handled and disposed of in a proper manner during manufacturing to ensure the safety of the workforce and the sustainability of the environment. Maintainability: With most of the Phase Change Materials found naturally on earth, there are no foreseeable issues with the maintainability of the necessary PCMs. Maintainability is not a concern with man-made eutectics PCMs either as the base compounds used to create the eutectics are simply the naturally formed organic and inorganic PCM compounds. Furthermore, the most impressive feature of PCMs is that most compounds do not degrade thermal properties after numerous thermal cycles. This allows for the same PCMs to be used repetitively without the need for maintenance. Manufacturability: The use of PCMs is a relatively inexpensive addition to wearable thermoelectric generators. PCMs are readily available in the form of organic and inorganic compounds, which can be used to create more specific eutectic PCMs. If for whatever reason, one PCM becomes unavailable, it is possible to create a new compound that mirrors its beneficial properties by forming a new eutectic PCM in a lab. The newly formed eutectic PCM takes on new freezing and melting point characteristics. Operational: Of the three possible power generation mechanisms from thermal energy – pyro-electricity, thermal-mechanical-electrical energy conversion, and thermoelectricity – the latter is the most viable. This is because thermoelectricity takes advantage of the temperature difference between the surrounding environment and the human body, thus necessitating thermoelectric (TE) conversion and consequently generating the desired electrical energy. Essentially, the operations of this product will manipulate human heat energy in a non-obstructive and non-invasive manner through the concept of thermoelectric effect.10 Consider a pair of conductors, linked in such a way that once one side is heated, electrons must move to the cooler environment. When this is conducted repeatedly, a current will be generated in the process and can then be obtained through a miniaturized circuit for electrical energy harnessing. This product will thus capture the heat energy from human bodies, employ the principle of the thermoelectric effect based on the temperature difference between the human body and its surroundings, and consequently generate electricity . Social, Cultural, and Political: The advances in technology are moving at a rapid pace, promising to reach all parts of the world, including the most remote regions. This has promoted the accelerated acquisition of personal electronic devices, hence the associated high demand for electricity.11 Since these devices are powered by rechargeable batteries, lack or the failure (power outages) of charging sources would lead to disconnection. A need for a more reliable source is evident. Through this TE product, a self-sustaining and maintenance-free electronic system can be created and keep people connected to their electronic devices once and for all. This will keep the Internet-of-Things (IoT) up and running, therefore promoting social interactions. Cultural conservation would also benefit from the reduction of environmental degradation and emissions. Politically, more people would be connected, rendering service delivery possible at all times and in all places. The product has the potential to provide a huge positive impact on society, covering the cultural, social, and political development aspects. Usability: The product will be integrated into wearable heat spreaders, like a watch or T-shirts, to attain optimized heating and cooling effects. A sandwich approach, layering the TEG between the heat source (the skin) and the cooling source (PCM), will be employed to ensure that optimal airflow will enhance the overall temperature gradient. Distinct fabrication techniques must be employed so that the product has a very thin profile, is light-weight and easily portable, and can be integrated with normal clothing to cover a wide surface area.12 To improve user-friendliness, the ensuing fabric will be comfortable to wear and made of non-toxic materials. It will also be breathable, lightweight, and washable. This explains why TE is the most viable method of generating electric energy from thermal energy. Ethics: All ethical considerations must be observed during the design of any product. The product must comply with the set standards of production. It must not harm the wearer, directly or indirectly, and must be aesthetically sound. This project promises a design that is non-invasive and non-obstructive. In other words, the integrity of the wearer will be safeguarded at all costs. This confidence emanates from the fact that similar products have been in use, particularly in the medical field, whereby wireless monitors have been used in preventive healthcare.13 In terms of marketing, the necessary channels will be followed to comply with state and international regulations. Projected Timeframes: As of this moment, we have planned to further research PCMs and what the most practical scenario to apply their characteristics to our project will be. This should be completed by November 1st, 2020. Once we narrow down our choices of PCMs that meet the needs of this project, we will order the necessary PCMs and other testing materials. It seems likely that we may find some equipment already on hand in the lab, such as thermocouples to measure the change in temperature gradient and a heat plate to mimic the body as a heat source. This phase of the project should be completed by mid-November. Once we have the required equipment, we will run experiments testing our hypothesis. The testing phase will run from late November 2020 to mid-March 2021. This will allow for sufficient time to complete the final report of our finding