Senior Project QL+ CDR

8/3/2019 Senior Project QL+ CDR

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QL+ Body Temperature Regulating VestProject 43.a.01QL+ Challenger: Lisa Maddox

Faculty Advisor: Dr. Richard Savage

Team MembersMelissa Goss [email protected] Cubero [email protected] Lynch [email protected] Olsen [email protected] Jazayeri [email protected]
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


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Table of Contents

Introduction ........................................................................................................................... 3Background Information ..........................................................................................................4

Current Devices .............................................................................................................. 4Studies of Interest .......................................................................................................... 5Codes & Standards ........................................................................................................ 6

Objectives ............................................................................................................................. 6Design Development ............................................................................................................. 9

Liquid Filled Cooling ....................................................................................................... 9Evaporative Cooling ......................................................................................................10Conductive Material .......................................................................................................10Decision Matrices ..........................................................................................................11

Top Concept .........................................................................................................................11

System Block Diagram ..................................................................................................11

Meeting Project Requirements ......................................................................................13Supporting Work ............................................................................................................14

Preliminary Manufacturing Plans .......................................................................................... 14Preliminary Validation Plans .................................................................................................16

Method of Approach ......................................................................................................17Budget Allocation ..........................................................................................................18

References ............................................................................................................................ 19Appendices ............................................................................Error! Bookmark not defined.0

Appendix A ....................................................................................................................20Appendix B ....................................................................................................................21

Appendix C ....................................................................................................................22Appendix D ....................................................................................................................22Appendix E ....................................................................................................................23Appendix F ....................................................................................................................26Appendix G ...................................................................................................................26


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Introduction

Stakeholders/Target Audience

Individuals diagnosed with spinal injuries are oftentimes unable to regulate their body temperature belowthe site of injury. Unaffected individuals regulate their body temperature through conduction, evaporation

and radiation methods. Conduction heat loss occurs when the body comes into contact with a coolersurface (i.e. the ground), but evaporation and radiation heat loss depends on signals from the bodyscontrol center. Individuals with spinal damage are unable to relay messages from their sensory neuronsto the hypothalamus [1]. As a result, the hypothalamus is unable to stimulate vasodilation and sweating toinduce heat loss.

When temperatures exceed 104F, the inability to induce heat loss mechanisms poses threats to affectedindividuals. Specifically, elevated temperatures cause organ malfunctioning, cardiovascular problems andpotentially death [2]. Therefore, the purpose of this project is to produce a vest that is capable ofmaintaining the core body temperature of individuals with spinal injuries at 98.6F.

Challenger background and needs

The proposer of this project is Lisa Maddox. Maddox is a practicing MD that works with multiple sclerosispatients. She has requested a design for a thermal vest that is capable of cooling and heating to maintainan average body temperature of 98F. Ideally this device should regulate the core body temperature inenvironments that reach 110F.

Purpose of the project

The purpose of this project is to design a vest capable of maintaining an individuals core temperature at98F. Current vest models exist that utilize ice packs that are inserted into vest pockets. However, onceice packs melt, the excess water increases the overall weight of the vest. In addition, these vests onlycool the body for a limited amount of time. The overall purpose of this project is to create a battery-operated, light-weight, and functional vest that individuals will be inclined to use on a regular basis inwarm environments.

Project & Team Description

This is a two-quarter long project that aims to design a body temperature regulated vest. The first quarterwill be spent forming an initial design. The second quarter will be dedicated to building, testing andrevising the initial design.

The project team is composed of five members from biomedical, mechanical and materials engineeringbackgrounds. Melissa Goss will serve as the team lead to coordinate all correspondence with QL+,manage the project budget and submit project reports. Greg Olsen will serve as the lead communicatorwith the project challenger and faculty. Other members will be appointed various positions as the designprocess develops.


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Background

Current Devices

Currently, there are five leading types of thermal vests: Ice-pack, evaporative cooling, phase change, fluidcooling and air cooling. A detailed analysis of each vest type is included below. Further specifications for

all devices are included in Appendix A.

Ice-Pack Vest

Ice-Pack vests involve inserting frozen ice-packs into the pockets of jackets. Ice-Pack vests can lastanywhere between two to four hours [3]. Ice-pack vests are low-cost, have a high cooling power and theice packs are able to be reused. However, after melting ice-pack vests can weigh between five and tenpounds. In addition the ice-packs require time to re-freeze. Another disadvantage is the fact that the vestis always in use, even when the body temperature is already at 98F.

One current model is the kold-vest [4]. This device uses ice packs to induce cooling. The vest canoperate for up to two hours. This is a light-weight design that uses reusable ice packs. The vest costsaround $150.00.

Evaporative Cooling Vests

Evaporative cooling devices use polymer materials soaked in water [5]. Over time, the water willevaporate from the vest in order to cool the bodys surface. The device must be submerged in water for 1 -3 minutes in order to operate for a period of 5-10 hours. These devices are often lightweight, low in cost,have high performance in dry climates, offer durability, operate without the use of ice packs, demonstratea long performance time. However, these devices require soaking the garment in water which can beinconvenient for the user, have poor performance in high humidity climates and have the lowest overallcooling energy.

One current product is Gemplers Evaporative Cooling Vest [6].The vest is composed of a polymerembedded fabric that is activated by water. This device must be submerged in water for 1-2 minutes andhas an operating time of 5-10 hours. This design costs approximately $36.15.

Phase Change Vests

Phase change vests use a polymer formula to help aid in cooling. Phase change materials becomeactivated at a certain temperature between 0-30C [7]. In a thermal vest, the phase change materialwould become activated when the body reaches a certain temperature. At this point, the phase changematerial would begin to melt in order to cool the body primarily through conduction mechanisms.Common phase change materials include ice packs, dry ice, and the most commonly used: paraffin wax.Typically these vests range in cost between $150 and $300.

The phase change material is able to cool an individual between 2-3 hours [7]. This method is a passiveprocess that offers a controlled release of a constant temperature which makes these devices easilycustomizable. They do not require the use of a freezer, and they offer an effective cooling method in allclimates. The disadvantages include high cost replacement parts and heavy weight after melting.

However, these devices can only cool for approximately 3 hours, they weigh more than other coolingdevices, they can have a higher cost and their total cooling power is less than cold pack systems

A current model is the Cooling Vest of TST Sweden AB [8].This model inserts PCM material into thepockets inside the vest. The PCM material melts at 28C and can cool the body for up to two hours. Thevest can be recharged in an air conditioned room, a refrigerator or freezer. Another advantage is that thevest weighs only 2 kilograms.


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Fluid Cooling

Active cooling vests pump coolant through a series of tubes embedded within the vest. The coolant canbe activated by temperature sensors and the temperature of the coolant can be adjusted. This design cancost up to $500. The advantages of this design include high efficiency, long cooling periods, can quicklyremove a large amount of heat and no wetting is required. The disadvantages include high cost, highenergy requirements, need for a water reservoir and the use of a pump. They are also heavier designsthat limit the movement of the user.

Current models of this device include the Polar Active cooling vest [9]. This product circulates cool waterthrough the vest. It comes in both fitted and adjustable versions. The vest uses a 15 quart wheeled coolerto provide water to the device. The device and cooler are connected by a retractable cord that can bedisengaged when not in use. The product costs $810 per vest.

Air Cooling

These devices direct compressed air around the body from an air supply system which allows excesssweat to be removed through evaporation. These devices are very comfortable, lightweight, and easilyadjustable. However, these devices require more energy and therefore add expenses.

Current market products include the Kool-Vest [10]. Fresh air is distributed through small holes in the vestto provide evaporative cooling across the worker's back, chest, and face. The vest operates with only 10- 20psi to accommodate a vortex cooling tube.

Another market product is the Personal Air Conditioner [11]. This device uses vortex tubes to separatecompressed air into warm and cool streams. The advantage of this model is that it can heat and cool anindividual. The disadvantages include high market price (approximately $500+) and the requirement to beconnected to compressed air.

Studies of Interest

Thermoelectric Cooling

These devices run electric current through the wires of the thermoelectric coolers which apply a voltage of

constant polarity to a junction between two metals. This creates a hot and a cold side, with heat sinks thatare responsible for transferring the thermal energy from the hot object, in this case the skin, to an objectwith a lower temperature, the environment.

This method is compact, inexpensive, and allow for the process to be reversed, presenting the option ofthe vest to not only cool, but to also heat. These systems are also inefficient when compared toalternative cooling methods, and they require a constant supply of power.

One study using this method incorporated a thermoelectric cooler into an evaporative cooling design[5].

Evaporative Cooling

Another study of interest is the Personal-portable Cooling Garment Based on Adsorption VacuumMembrane Evaporative Cooling by Yifan Yang [12]. Yang designed a thermal vest that used evaporative

cooling methods. Using the AVEC cooling method, a cooling capacity of 179 W/m2 was obtained over aperiod of four hours.


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Codes and Standards

The vest must not cause harm to the user. Specifically, the fabric and design must not cause skin burns,friction burns or pressure sores.

Regarding FDA standards, important codes to consider include 21CFR890.9, 21CFR890.5720,21CFR890.5940 [11]. Code 890.9 addresses issues regarding premarket notification. Code 890.5720addresses the issue of using circulating water in a cooling or heating pack. Depending on the final designselection, additional FDA codes and standards may need to be considered.Specific FDA codes areincluded in Appendix B.

In regards to testing considerations, a model that accurately represents the conditions of an individualwith a spinal cord injury is required. Other models used a torso replica that was capable of modelingevaporative, or sweating, cooling mechanisms [5]. In individuals with spinal injuries, sweating is oftenimpaired below the site of injury.

Objectives

The overall goals of this project are to design a lightweight, non-bulky jacket that uses thermal sensors toregulate an individuals core temperature.

Customer Requirements

The following list contains the proposed customer requirements. These requirements were chosen tocreate a user-friendly device that can be used on a regular basis.

Durable

Lightweight

Non-insulating

Functional for at least 8 hours

Maintain core temperature of 98F

Moderated by a thermostat

Can be worn under clothing

Adjustable for different sizes

No system failure

User-friendly

Reduced number of false alarms

Lithium ion battery source

Chemical based system


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Project Requirements

Based on the proposed customer requirements, the following qualitative performance goals wereproposed. These qualitative performance goals were then transformed into quantitative functional goals.

Performance Goals

Durability Withstand drop from 8 ft.

Light Weight Less than 5 lbs

Non-Insulating Fabric must be breathable

Long Lasting Self contained operation 8 hours

Maintain Core Temp Reduce temperature from 110 to 98 and regulate

Thin and compact design Fit under a T-shirt

Reliability All components must last 10^6 cycles w/ 95% reliability

User Friendly User fully Functional after 3 attempts, Comfortable

Washable Must be water resistant

Cost Expenses must be under $5,000

Adjustable Must be able size from small to large shirt size

Safety Must be able to operate without any impending danger to user

Functional Requirements

Durability Withstand drop from 8 ft

Light Weight Less than 5 lbs

Non-Insulating more than 170 gram/(hour meter^2) of water permissibility


Maintain Core Temp Must expel 1000 BTUs/hour

Thin and compact design Vest must protrude off the body by no more than 1/4 inch

Reliability All components must last 10^6 cycles w/ 95% reliability

User Friendly User fully Functional after 3 attempts

Washable Must be able to function after being submerged in 5 PSI of water

Cost Must cost less than $2000 to build and test

Adjustable 30 inch chest to a 46 inch chest

Safety All contact materials to be biocompatible

The functional goals were then compared using a rank order comparison shown in Appendix C. Based onthe rank order comparison the top four goals were determined to be maintaining core body temperature,safety, light-weight design and non-insulating materials. Detailed explanations for these goals areincluded below.

Maintaining Core Body Temperature: Must expel 1000 BTUs/hour

o The main goal of this project is to regulate an individuals body temperature at 98degrees. If this standard is not met, then ultimately the design does not achieve its overallpurpose. In order to maintain an individuals body temperature, 1000 BTUs/hour must beexpelled.


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Safety: All contact materials to be biocompatible

o This device must not be dangerous to use. In order to be FDA approved, certainstandards must be met to ensure user safety. Furthermore, it is important that materialsare selected that dont cause skin lesions or burns.

Light-weight: Less than 5 lbs

o In order to be used on a daily basis the design must be light-weight. This will ultimatelyincrease the users satisfaction and increase the device usage.

Non-insulating: more than 170 gram/(hour meter^2) of water permissibilityo The material must be able to expel excess heat to prevent the user from overheating.

Other goals that ranked relatively high included a thin & compact design, reliability of device and long-lasting.

Thin & Compact Design: Vest must protrude off the body by no more than 1/4 inch

This will allow the vest to lie below an individuals clothing.

Reliability: All components must last 10^6 cycles w/ 95% reliability

This device is responsible for regulating the body temperature in high temperature environments.It must be 95% reliable to ensure that the individual does not succumb to heat stroke.

Durability: Withstand drop from 8 ft

Must be durable enough to withstand normal daily conditions. If the device can withstand an 8foot drop, then it should be able to withstand daily activities.

Long Lasting: Self contained operation 8 hours

This will allow the user to wear the vest during a standard eight hour work day.

The least important goals at this time are adjustability, washable and low-cost.

User-Friendly: User fully Functional after 3 attempts

Must not be a difficult device for the user to operate. They must be able to use the device withminimal instructions.

Adjustability: 30 inch chest to a 46 inch chest

These are the dimensions of average female and male chest sizes.

Washable: Must be able to function after being submerged in 5 PSI of water

If the user is using the device on a daily basis, it must be washable.

Cost: Must cost less than $2000 to build and test

This is the cost for building and prototyping. Individual units may be more expensive than existingmodels. The rationale for a higher unit cost is dependent on the fact that this device will be usedon a daily basis.


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Design Development

Based on the design requirements outlined above and preliminary background research, three topconceptual models were designed: the liquid cooling vest, the evaporative cooling vest and theconductive material and phase change vest. Each model is discussed in detail below.

Liquid Cooling VestThe liquid cooling vest pumps liquid throughout the vest to produce a cooling effect. Liquid is stored in afluid reservoir and is cooled by a thermoelectric cooler. Figure 1 shows the configuration of the liquidcooled vest design.

Figure 1. Liquid Cooling Vest Configuration.

As the liquid travels through the vest-lined tubing, it absorbs heat from the body. The fluid then enters thefluid reservoir, where the thermoelectric cooler (TEC) works to cool the water and remove the heat fromthe vest reservoir into the surrounding environment.

Benefits of this design include increased efficiency and high thermal conductivity. However, this designmay also be bulky and heavy for the user. In addition, the current design must be continuously poweredand has the potential to leak.


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Evaporative Cooling Vest

The evaporative cooling vest uses an air pump in order to remove heat from the user. The vest material isslightly dampened to facilitate heat transfer reactions between the users skin and the fluid tube.Evaporative and convective forms of heat are emitted from the users skin to the fluid tube. From here,heat enters the inlet and outlet where it is removed from the system through a TEC.

Figure 2. Evaporative Cooling Vest Configuration.

The benefits of this design include a passive form of cooling that is lightweight. The disadvantages of thisdesign include the need for water components and a bulky design.

Conductive Material Vest

The conductive vest operates similar to a heating blanket. Heat from the body comes into contact with a

conductive material and then a TEC in order to expel heat into the surrounding environment.

Figure 3. Conductive Material and Phase Change Cooling Vest.

Benefits of this design include a simple design schematic. However some disadvantages of this designinclude the need for extensive wiring. This may increase the likelihood of negative side effects to the user(i.e. increased likelihood of burns). Also, this is not an efficient design.


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Decision Matrices

To compare the three models a Pugh Matrix was created. The liquid cooling vest was selected as thedatum since the most research has been conducted regarding this design.

Based on the Pugh Matrix included in Appendix D, both the evaporative and phase change vests onlyhad one advantage over the liquid cooling vest. In addition, they each had several disadvantagescompared to the liquid cooling vest and ranked the same in the remaining categories. Therefore, theliquid cooling vest was selected as the final design.

Top Concept

The liquid cooling vest uses a water reservoir, a thermoelectric cooler, vest tubing and a pump to cool ahuman body. Fluid is pumped through the vest tubing from a water reservoir. The fluid absorbs heat fromthe body and carries it back to the reservoir. The reservoir is connected to a thermoelectric cooler whichabsorbs heat from the water and removes it the surrounding atmosphere. At the same time, the water ischilled and prepared to circulate through the tubing as shown in figure 1.

The vest will be configured from two different materials, with tube lining within. The inner material will be ahighly conductive material. The outer material will be insulating from the outer environment and

permeable for evaporative cooling.

System Block Diagram

Figure 4 shows the system diagram of the proposed design. Specific details of each component aredetailed below.

Figure 4. Device System Block Diagram.

AX: Electrical Energy TransferBX: Mechanical Energy TransfeCX: Thermal Energy Transfer


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A.1Thermal sensors throughout the vest send a voltage potential to an electrical circuit which will activate thethermal vest system if the voltage potential is great enough.

A.2The electrical circuit allows the battery to power the active cooling components of the vest. The coolingfan, the thermoelectric module, and the pump are activated.

A.3Any operating power the system needs to maintain the off and on temperature sensing regulations issupplied by the battery power source.

A.4The system activates the coolant pump at a fixed speed to circulate the cooling or heating fluid though thevest tubes.

A.5The battery sends power to the thermoelectric module which converts the electrical potential into atemperature difference between two plates. The amount of supplied voltage depends on how much the

wearers core temperature deviates.

A.6The battery supplies electrical power to the cooling fan to cool the heat exchanger on the waste side ofthe thermoelectric module.

A.7The battery power source can be recharged from an external AC power source.

B.1The coolant pump converts the electrical energy into mechanical work to circulate the coolant through thecooling vest.

B.2The cooling fan converts electrical energy into mechanical work to remove the hot air in the microclimateof the hot plate thermoelectric cooler heat exchanger. This fan will operate for as long as the vest isactive.

C.1The thermoelectric module cools or heats a heat exchanger/fluid reservoir

C.2Thermoelectric module waste plate thermally exchanges energy with a heat exchanger.

C.3The fluid reservoir intakes coolant to thermally treat to operating temperature before recalculating.

C.4The fluid reservoir expels operating temperature fluid to be circulated through the vest.

C.5Operating fluid thermally transfers energy to the conductive tubing throughout the vest.

C.6The conductive tubing conducts heat with the surface of the body.


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Meeting Project Requirements

Functional Requirements

Objective Requirement Justification

Durability Withstand drop from 8 ftAll materials can withstand drops from8 ft.

Light Weight Less than 5 lbsInitial iteration may be more than 5 lbsbut no more than 10 lbs.

Non-Insulatingmore than 170 gram/(hour meter^2) ofwater permissibility

Inner and outer vest materials will beable to conduct heat away from body


Batteries will be selected to providedevice-operation of 8 hours per singleuse

Maintain CoreTemp Must expel 1000 BTUs/hour

Per MATLAB code, design shouldexpel 1700 BTUs/hour from the usersskin

Thin and compactdesign

Vest must protrude off the body by no morethan 1/4 inch

Vest will measure inch from thebody. Future iterations can reduce thisthickness

ReliabilityAll components must last 10^6 cycles w/95% reliability

Only component that may needs to bechanged often will be the battery

User Friendly User fully Functional after 3 attempts

First iteration will use an on/off device,user will be able to use device afterfirst use

WashableMust be able to function after beingsubmerged in 5 PSI of water

Design will be able to be hand-washed

Cost Must cost less than $2000 to build and test Will cost $1100 for raw materials

Adjustable 30 inch chest to a 46 inch chest Materials can be adjusted.

Safety All contact materials to be biocompatibleMaterials selected will not cause harmto user


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Supporting Work

In order to determine the validity of the proposed design, MATLAB code was used to model heat transfer

throughout the model. First this model makes several assumptions:

System is at steady-state

The atmospheric temperature is known Surface area of the temperature is 5.4 ft

2

TEM operates at steady-state

Copper surface acts as an instantaneous conductive surface

Based on these assumptions and several user inputs, the component operating temperatures, input

energy required and the steady state ration can be predicted. Based on initial simulations the proposed

model should dissipate 1700 BTUs per hour from an individuals skin. The full MATLAB code is contained

in Appendix E.

Preliminary Manufacturing Plans

Material Selection & Comparison

Tubing

The first step in finding a suitable material was identifying a flexible, durable material that could be

injection molded into tubing for our vest. Other key features required were high thermal conductivity which

was also lightweight. Using CES we analyzed thermal conductivity versus density in order to find

materials that would suit our thermal conductive needs and then used a limiting stage to show materials

that could be injection molded, had adequate durability, and Youngs modulus. From CES we determined

that a thermoplastic elastomer would be the most effective material for tubing. Using this information we

found a company, Cool Polymers, that creates tubing for thermally conductive processes. CoolPoly

D8102 Thermally Conductive Thermoplastic Elastomer (TPE) was selected, which is commercially

available and meets all of our needs (See MSDS and Material Data Sheet).

Vest Material

Since the vest is designed with an inner and outer layer there are two parts to vest material selection

Outer Layer

The external vest fabric must thermally insulate the cooling tubes of the vest from the

environment. The fabric must also be highly permeable, to allow for evaporation and comfort of

the user. The fabric used in Under Armor ColdGear was selected because it met the

requirements for this design. The fabric has similar properties to the conductive vest fabric

selected, but is much more thermally insulating.

Inner Layer

The inner layer is more important and must have good thermal conductivity, moisture

management, and Tactile Properties (Cao).Moisture management and tactile properties are

important because they improve comfort for the user and add structure for the vest. Using the

information from the Textile research journals Fabric Selection for a LCG we determined that a

material of 80% polyester, 20% spandex knit would be the ideal inner material. CES does not


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include fabrics, so fabrics used in sports applications and commercially available materials were

examined. A fabric Under Armor HeatGear (84% Catonic Polyester, 16% Elastane) was

selected because it met all of the requirements for this design and was the most similar material

commercially available to the theoretical material.

Heat Exchanger

The heat exchanger must have a high thermal conductivity and the ability to be formed from sheet. Due to

its portable nature it must be light weight, though must be durable to avoid deformation due to daily wear

and tear. Due to the fact it is in constant contact with water it needs to be able to withstand corrosion

associated. Aluminum 6060 T6 was chosen because it is commercially available meets all requirements.

Copper Alloys were eliminated due to their high cost and tendency to corrode when exposed to water.

Copper plate

The material for the conductive plate must be highly thermally conductive. The highest possible thermal

conductivity is needed, at a reasonable price. A graph was made in CES plotting thermal conductivity

against price. Materials priced over $100/lb were eliminated because these materials were only slightly

more conductive (~5 Btu.ft/h.ft^2.F) and significantly more expensive (~$250/lb). The resulting materialswith highest thermal conductivity were a set of copper alloys (C10100, C15100, C18100, C10200,

C10500). All of these materials were approximately the same density, so density did not factor into the

selection. C10100 was selected because it is highly durable and commonly used in heat transfer

applications, such as radiators.

Ceramic plate

The insulating plate must have a low thermal conductivity, while being lightweight to minimize the weight

of the vest. Thermal conductivity was plotted against density. The maximum temperature that the plate

might be exposed to would be 120F, so all materials with a melting temperature below 140F were

eliminated. The resulting materials were PE Foam, PP Foam, and PE-LD Foam. Of these materials, PP

Foam was the most durable when exposed to water, acids, alkali, and organic solvents. The materialselected was PP Foam (Closed cell, 0.030), which is found under the trade name Neopolen P30.


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Preliminary Validation Plans

When developing top design concepts various testing methods were considered. The ability to validatethe efficiency of pieces of the design will continue to play a large role in the details of the final model thatwill be developed. The preliminary validation plans are based on testing methods previously exploredwhich were detailed in the background research gathered.

One study developed a cooling pad assembly to simulate the cooling effect of their product. The test useda water bag to simulate the cooling core and desiccant powder, which is a substance that generates a dryvicinity, as the source of absorption from the core. To prevent contact between these two layers, ahoneycomb spacer was incorporated into the design. The outer bag in this experiment was a genericvacuum storage bag which provided thermal insulation along with the air tight environment suitable forevaporation. Vinyl tubing was used to connect this cooling pad to the pump supplying power to thesystem. Once the pump was turned on the leads for the thermocouple were attached to the surfaces ofeach core with tape and timed weight readings of the system were taken to account for the water lossduring the procedure. Easily available materials like these will be used in our initial testing plans to testbasic cooling capacity of the system.

Control Test

The initial testing plans include four different simulations. The first one will test the Veskimo liquid coolingvest purchased as a standard to compare our final design to. The test will be comprised of a run on atreadmill with a controlled speed and time span wearing the cooling vest. This data will then be comparedto a similar run without wearing the cooling vest. To conduct this test properly and thoroughly we will bemonitoring mean skin torso temperature, time span, distance of the run, vest flow rate, and temperatureflowing into and out of the reservoir. During the simulation with the cooling vest, the individual will wear atrash bag over the vest to prevent evaporative heat transfer from occurring. To conduct this test 6thermocouples, data acquisition software, the cooling vest, ice, trash bags, a stopwatch, and a treadmillare needed.

Test #2

The second test will test the performance of the heat exchanger. To test the performance of the

exchanger we will heat an aluminum cylinder to a fixed temperature and fill a bucket with cold water at afixed temperature. We will then pump the cold water from the first bucket through the aluminum heatedcylinder and into a final bucket. The temperature of the water in the final bucket will be measured andcompared to the initial fixed cold temperature. The difference calculated will allow us to determine theamount of heat that the heat exchanger provided to the water. For this test two buckets, a sized aluminumcylinder, two pumps of equal size, tubing, water tight connections, four thermocouples, and dataacquisition software are needed

Test #3

The third test will test the thermoelectric module performance. We will have three different trials: oneheating trial, one cooling trial, and one without the copper plate to test the heating of the TEM.

Test #4

The fourth test will measure skin-vest tubing performance. We will have an aluminum cylinder with siliconsheeting around it to represent the skin. A cylinder will be filled with water and a heater will warm thewater inside the cylinder. Convective tubes will then be used to cool the water. From her we candetermine the performance of the design schematic.


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Management PlanMethod of Approach

This project will be two quarters long. The first quarter will be dedicated to background research,formation of design requirements, determination of top conceptual models and the selection of the finaldesign. The first qarter will also include the creation of CAD models and the selection of final product

materials. The second quarter will be dedicated to manufacturing and testing the final design. Revisionswill be made based on the test results. The project should be completed by Monday, March 6

th, 2012. The

following table details the reports to be submitted to QL+ and project milestones.

Date Deliverable or MilestoneMonday October 3

rTeam ContractStatement of Work

Monday October 10t

Project Planning (Gantt Chart)Monday October 31

stDesign ReviewPreliminary Project Report

Monday November 14t

CAD Design DrawingsMonday November 21

stDesign ReviewBill of Materials

Monday December 5t

Concept Design ReportFinal Materials SelectionMonday January 2

nPrototype Manufacturing

Monday January 16t

Prototype Initial TestingMonday January 23

t Interim Design Report

Monday February 6t

Final Testing & Data AnalysisMonday March 6

t Final Project Report

Design Notebooks DueProof-of-Concept Prototype

The following flow chart diagrams the general process that will be utilized to complete this project.

BackgroundResearch

Customer &

EngineeringRequirements

Contact QL+

Challenger

Revise Engineering

Requirements

Selection of Top

Concepts, MATLABverification

Initial Drawings &

Solid Models

Selection of Final

Design Concept

Create CAD DesignsSelection of

Materials

Create Test Plans

Construct

Prototype(s)

Test Prototype(s) Analyze Test Data

Revise Prototype

Design(s)

Repeat Testing, if

needed

Submit Final

Prototype & Report


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At this point, the problem has been defined and background research conducted. Based on this researchthe initial design requirements were formed. After meetings with the QL+ Challenger and Engineer, theserequirements were further redefined. The top conceptual models were verified in MATLAB to determinethe maximum power input. A Pugh comparison showed that the fluid cooling vest was the best design..

At this point the final material selection will take place. All materials will be ordered over the next threeweeks. The first two weeks of January will then be spent assembling the components to be tested. Fourtests will be designed to test vest performance, heat exchange, TEC module performance and skin tovest tube heat transfer. Based on these tests further revisions to design and testing plans will be made.

A detailed Gantt chart is included in Appendix F to measure project progression.

Budget Allocation

The budge was broken into two areas: vest and test materials. Based on cost estimates from onlinevendors and local stores the total cost for the vest and tests totaled $1968.64.

Table 1. Vest and Test Materials Costs

Specific breakdowns for the vest and test materials are included in Appendix G.

Cost ($)

Vest 699

Test #1 452.34

Test #2 238Test #3 170

Test #4 409.3

Total Cost 1968.64


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References

[1] Schmidt KD, Chan CW.Thermoregulation and fever in normal persons and in those with spinal cordinjuries.Mayo Clin Proc. 1992 May;67(5):469-75. Review. PubMed PMID: 1405774.

[2] Staff, Mayo Clinic. "Heat Stroke - MayoClinic.com." Mayo Clinic. Mayo Clinic..

[3] "Cooling Vest." Ms Cooling - Body Cooling Devices and Other Personal Cooling Products. MS CoolingClimate Control Products. .

[4] "Pro-Kold - Kold Vest and Ice Wrap Products." Pro-Kold Reusable Ice Wraps. Dura*Kold, 2011..

[5] DAngelo, Sophia, and William Lauwers. "The Cooling Vest Evaporative Cooling." Diss. WORCESTERPOLYTECHNIC INSTITUTE, 2009. Print.

[6] "Evaporative Cooling Vest, Cooling Workwear - GEMPLER'S." GEMPLER'S - Outdoor Work Supplies,Spray Equipment, PPE & More. GEMPLER'S..

[7] "Gear Guide: Cooling Vests & Apparel." ActiveMSers: Staying Active With Multiple Sclerosis.ActiveMSers: Staying Active With Multiple Sclerosis..

[8] "TST Sweden AB Body Temperature Control Vest "Cooling Vest"" GADELIUS. GADELIUS..

[9] "Circulating Cold Water Cooling Vest System for People with MS,surgeons, Race Car Drivers, TruckDrivers and Many Other Applications." PolarProducts.com Polar Products Body Cooling Vests.Polar Products Inc. Web. 31 Oct. 2011. .

[10] "Body Cooling Systems." Welcome to Air Systems International, Inc. On-Line Catalog. Air SystemsInternational, Inc.

.

[11] "Diffuse Air Vest with Unfolding Lapels: 855." Efficient Compressed Air Techology | ITW Vortec.Vortec. .

[12] Yang, Yifan. "Personal-portable Cooling Garment Based on Adsorption Vacuum MembraneEvaporative Cooling." Diss. University of Ottawa, 2011. Print.

[13] "Code of Federal Regulations Title 21." US Food and Drug Administration. Department of Health andHuman Services, 1 Apr. 2011. Web..
http://www.ncbi.nlm.nih.gov/pubmed/1405774http://www.ncbi.nlm.nih.gov/pubmed/1405774http://www.ncbi.nlm.nih.gov/pubmed/1405774http://www.ncbi.nlm.nih.gov/pubmed/1405774http://www.ncbi.nlm.nih.gov/pubmed/1405774http://www.ncbi.nlm.nih.gov/pubmed/1405774


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Appendix A

Evaporative Cooling Properties

Cooling Time 5-10 hoursVest Sizes S, M, L, XL, 2XL or 3XLMaterial Nylon outer with polymer embedded fabric inner.

Black poly-cotton trim.Price $36.15

Phase Change Cooling Properties

Vest Weight: Approximately 2 kilogramsVest Size:

SizeChestCircumference

S-M 84-100cmL-XL 100-116cmXXL-XXXL

116-132cm

Vest Types: Two types; PCM melting point of 28 and 32Vest Material: Polyester

PCM Material:Mixed salt (interior), Valeron coating aluminum(exterior)

Fluid Cooling Properties

Sizes Adjustable S, M/L, L/XLDesign 9 foot of insulated water lines from the cooler,

optional 5 ft length instead of 9 ft or additional 4foot lengths are also available.

Cooling system 15 quart wheeled cooler with retractable handle

Price $810

Air Cooling (Kool Vest) Properties

Material Double coated PVC on nylon scrim material withVelcro front closures and sewn-in adjustable belt

Add ons vortex adapter or Air Systems' uniqueCool-BoxCooling method Small holes on interior of vest direct air to

complete upper torso, front and rearLayout/Design Specially designed plenum directs air to a neck

ring for cool air distribution to the neck and face. Arear Velcro strip controls the air volume to the

neck ring
http://www.airsystems.cc/product_pages/compressors/the_cool_box.htmhttp://www.airsystems.cc/product_pages/compressors/the_cool_box.htmhttp://www.airsystems.cc/product_pages/compressors/the_cool_box.htmhttp://www.airsystems.cc/product_pages/compressors/the_cool_box.htmhttp://www.airsystems.cc/product_pages/compressors/the_cool_box.htm


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Air Cooling (Personal Air Conditioner) Properties

Item # Description Cooling Capacity Price($)

22815 Vortex Air Conditioner withBelt 900 BTUH

900 Btu/hr 114


1500 BTU/hr 114


2500 Btu/hr 114

220 Hot/Cold Air Conditionerwith Belt 1500 BTUH

1500 Btu/hr 302

855 Diffuse Air Vest withunfolding Lapels

199

Thermoelectric Cooling Properties

TEC temperature hot side temp is27C,50C, maximum watts range between 20 and 22

Power Supply ATX 300 Watt power supplyMaterial mesh lined vest,

wicking material was a sheet of Shamwow

Appendix B

PART 890 -- PHYSICAL MEDICINE DEVICES

Subpart A--General Provisions

Sec. 890.9 Limitations of exemptions from section 510(k) of the Federal Food, Drug, and Cosmetic Act(the act).

Sec. 890.5720 Water circulating hot or cold pack.

(a)Identification. A water circulating hot or cold pack is a device intended for medical purposes thatoperates by pumping heated or chilled water through a plastic bag and that provides hot or cold therapyfor body surfaces.

(b)Classification. Class II (special controls). The device is exempt from the premarket notificationprocedures in subpart E of part 807 of this chapter subject to 890.9.

[48 FR 53047, Nov. 23, 1983, as amended at 63 FR 59231, Nov. 3, 1998]
http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=890http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=890http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=890


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22

Appendix C

Appendix D

Liquid Evaporative Conductive

Durability D S S

LightWeight + +Non-Insulating A S S

Long Lasting S -

Maintain Core Temp T S SThin and compactdesign - -

Reliability U S S

User Friendly - -

Washable M S S

Cost S S

Adjustable S S

Safety S S

+ 1 1

- 2 3

S 9 8

Maintain Core Temp Safety LightWeig Non-Insulating Thin and c Reliability Durability Long Lasti User Frien Adjustable Washable Cost

Durability 1 1 1 1 1 1 ** 0.5 0.5 0.5 0.5 0

LightWeight 1 1 ** 0.5 0.5 0.5 0 0 0 0 0 0

Non-Insulating 1 1 0.5 ** 0.5 0.5 0 0 0 0 0 0

Long Lasting 1 1 1 1 0.5 0.5 0.5 ** 0.5 0.5 0 0

Maintain Core Temp ** 0.5 0 0 0 0 0 0 0 0 0 0

Thin and compact design 1 1 0.5 0.5 ** 0.5 0 0.5 0 0 0 0

Reliability 1 1 0.5 0.5 0.5 ** 0 0.5 0 0 0 0User Friendly 1 1 1 1 1 1 0.5 0.5 ** 0.5 0 0.5

Washable 1 1 1 1 1 1 0.5 1 1 0.5 ** 0.5

Cost 1 1 1 1 1 1 1 1 0.5 0.5 0.5 **

Adjustable 1 1 1 1 1 1 0.5 0.5 0.5 ** 0.5 0.5

Safety 0.5 ** 0 0 0 0 0 0 0 0 0 0

Sum 10.5 10.5 7.5 7.5 7 7 3 4.5 3 2.5 1.5 1.5

Percentage 15.91 15.91 11.36 11.36 10.61 10.61 4.55 6.82 4.55 3.79 2.27 2.27


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23

Appendix E

%% This Program Models the Thermal System of the Liquid Filled Active Cooling

Thermal Vest%% Inputs: Heating/Cooling, Atmoshperic Temperature, Energy Dissipation,

Fluid Flow Rate,TEM Temeprature Difference%% Outputs: Input Parameters, Component Operating Temperatures, Input Energy

Required, Steady State Ratio%% Assumptions:

% System is at steady state at all heat transfer locations% Human Body needs to expel 1000 BTU/hr to maintain the core body temp% Atmospheric temperature is defined% Surface Area of torso is approximatetly 5.4 ft^2% TEM is operating at steady state% Copper Surface acts as instaneous conductive surface%% Clear Work Spaceclc;clear;%% Inputs% Cooling or Heating

i=1; % i=1 for cooling, i=anything for heatingif i==1n1=.3; %Nud Coeficient

elsen1=.4;

end% Constant Inputsgrav=32.2; %Gravitational Constant (ft/s^2)Egen=1000; %Body heat generation (Btu/hr)

Tskin=91; %Temperature of the skin (F)Tatm=100; %Atmospheric TemperatureAcds=10.8*.5; % Surface area of Torso (ft^2)% Tube InputsID=4/16; %Tube Inner Diameter (in)Acs=(ID/2/12)^2*3.14; %Area inside of tube (ft^2)OD=5/16; %Tube Outer Diameter% TEM InputsdT=50; % TEM side Temperature difference (K) not heat sink

temp (K)Vin=1.15*(dT/60); % DC Voltage InputIin=9; % Input Current (Amps)Ein=Vin*Iin; % Input Energy (Watt)Len=6; % Lenght of TEM (in)Wid=1; % Width of TEM (in)qss=.932; % Equivalent Conduction Heat transfer shape FactorArea=Len*Wid; % TEM Conductive Surface Area (in^2)Khs=250; % Thermal Conductivity of Heat Sink Material(W/(m*K))

% Fluid Propertiesvis=1.052*10^-5; %Kinematic Fluid viscosity (ft^2/s)uvis=2.034*10^-5; %Dynamic Fluid Viscosity (lb s/ft^2)den=uvis/vis; %Fluid Density (% Pump InputsGPM=.03432*.002228; % Nominal Gallons per minute at max voltage (ft^3/s)mdotpu=GPM*den*grav; % Pump Mass flow rate (lb/s)Vpu=26; % Pump Input VoltageIpu=.18; % Pump Input AmpsEpuin=Vpu*Ipu; % Pump Input max power (watt)


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vel=mdotpu/(den*Acs); % Fluid Velocity (ft/s)% Fluid Flow PropertiesRe=vel*(ID/12)/vis; %Reynolds NumberPr=7; %Prandtl Number

k=355; %Fluid Thermal Conductivity (BTU/(hr*ft*F))% Resivoir InputsResLen=8/12; %Resivoir Lenght (ft)ResWid=.5; %Resivor Width (ft)Resthi=1/12; %Resivor Thickness (ft)FinNumro=3; %Number of conductive fin rowsFinNumco=2; %Number of Conductive Fin Columnsdfin=1.5; %Diameter of cylindrical fins (in)Afin=(dfin/12)^2/4*3.14;%Fin Area (ft^2)reswath=.5; %Resivoir wall thickness (in)reswath2=1/10; %Resivoir wall thickness longitudinal (in)lenfin=Resthi-2*(reswath2)/12;%Fin Length (ft)AinRes=(ResLen-2*reswath/12)*(Resthi-2*reswath2/12)-

FinNumco*(lenfin*dfin/12); % Internal area inside Resivoir ft^2Presin=(((ResLen-reswath/12*2)*(ResWid-reswath*2/12))-

(FinNumro*FinNumco*(3.14/4*(dfin/12)^2)))*2+((ResWid-2*reswath/12)*(Resthi-

reswath2*2/12))*2+((ResLen-reswath*2/12)*(Resthi-reswath2*2/12))*2+(FinNumco*FinNumro*lenfin*3.14*dfin/12);Dh=2*(AinRes/Presin); %Effective Diameter of resivoir internal (ft)mdott=den*vel*Acs*grav; % Tube mass flow rate (lb/s) Fabric InputsKc1=.25; % Breathable Fabric Conduction Ceoficient (W/m*k)%% TEC Operating at Steady StateThp=(Tatm+80)/2+.5*dT; % TEM Hot plate operating TemperatureTcp=(Tatm+80)/2-.5*dT; % TEM Cold plate operating Temperature%% Conduction 2 2-D Conduction from TEC to Heat Sink Stage 1if i==1

Ths=Tcp-(-Egen/(qss*Area/12*Khs*(1/1.731)))*ResLen; %Temperature of

the Heat Sink for 1000(btu/hr) (F)else

Ths=Thp+(-Egen/(qss*Area/12*Khs*(1/1.731)))*ResLen;

end%% Convection 2 Internal flow Forced Convection Stage 2% Internal Model (Inside Thermal Resivoir)velres=mdott/(den*AinRes*grav);% Velocity of Fluid inside resivoirReres=velres*Dh/vis; % Resivoir Reynolds Numberif (Reres>=2500)

if (Reres>20000)fres=.316*Reres^(-1/4); % Turbulent friction Factor

elsefres=.184*Reres^(-1/5); % Turbulent friction Factor

endNudres=.023*Reres^(4/5)*Pr^n1; % Fully Developed Turbulent Flow

Nusselt

elseDevres=.05*Reres*Pr*Dh; % Lenght of Fully Developed Flow (ft)fres=64/Re; % Laminor Fully Developed Flow Friction

Factor

Nudres=3.66+(.0668*(1/Devres))*Reres*Pr/(1+.04*((1/Devres)*Reres*Pr)^(2/3)); % Laminor Fully Developed Flow Nusselt Number

(3.66-4.36) TypicalyendH2=Nudres*k/(Dh);


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if i==1Tf=Ths+Egen/(H2*AinRes); % Temperature of the Flowing Fluid

elseTf=Ths-Egen/(H2*AinRes);

end%% Convection 1 Internal Flow Stage 3% Fully developed flowif (Re>=2500)

Dev=10*ID/12; % Lenght of Fully Developed Flow (ft)if (Re>20000)

f=.316*Re^(-1/4); % Turbulent friction Factorelse

f=.184*Re^(-1/5); % Turbulent friction FactorendNud=.023*Re^(4/5)*Pr^n1; % (f/8)*(Re-

1000)*Pr/(1+12.7*(f/8)^(1/2)*(Pr^(2/3)-1));% Fully Developed Turbulent Flow Nusselt

elseDev=.05*Re*Pr*ID/12; % Lenght of Fully Developed Flow (ft)f=64/Re; % Laminor Fully Developed Flow Friction Factor

Nud=3.66+(.0668*(1/Dev))*Re*Pr/(1+.04*((1/Dev)*Re*Pr)^(2/3)); %LaminorFully Developed Flow Nusselt Number (3.66-4.36) TypicalyendH1=Nud*k/(ID/12); % Convection Coeficient (BTU/(hr*F*ft^2))if i==1

Ts=Tf+Egen/(H1*Acs); % Temperature of Conductive Surfaceelse

Ts=Tf-Egen/(H1*Acs);

end%% Conduction 1 1-D Stage 4Qcd1=Kc1*(1/1.731)*Acds*(Tskin-Ts)/((OD-ID)/12); % Conduction 1 Heat

Transfer (Btu/Hr)%% Total EnergyEtotal=Ein+Epuin; % Total Input Energy%% Display Resutltsdisp('Atmospheric Temperature');disp(Tatm);disp('Thermoelectric Module Plate Temperature Difference');disp(dT)disp('Operating Temperature of the Thermoelectric Module Contact Plate');if i==1

disp(Tcp);else

disp(Thp);enddisp('Operating Temperature of the Heat Sink');disp(Ths);disp('Operating Temperature of the Flowing Fluid');disp(Tf);disp('Fluid Flow Reynolds Number');disp(Re);disp('Fluid Flow Tube Velocity (ft/s)');disp(vel);

disp('Operating Temperature of Conductive Surface');disp(Ts);disp('Steady State Ratio');disp(Qcd1/Egen);disp('Pump Input Power to System in Watts');disp(Epuin);disp('TEM Input Power to System in Watts');disp(Ein);disp('Max Input Power to System in Watts');disp(Etotal);


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Appendix F

Appendix G

Component Material/Type Vendor/Model Volume/Quantit Price ($)Water Pump Micro Pump Xavitech 1 $100.00

Heat Exchanger 1 Aluminum 6060 T6 - 300 $0.00

Thernoelectic Module Multi Stage Custom Thermoelectric 1 $65.00

Fan Assembly Mini Comp Novak Elec tronics 1 $18.00

Heat Exchanger 2 Aluminum 6060 T6 - 20 $0.00

Copper Plate Copper - 2 $0.00

Polypropolene Foam Polypropolene Foam - 10 $0.00

Rechargeable Batteries Lithium Ion IDX NP-L7 NP1 1.00 $344.00

Internal Conductive Vest Fabric Under Armor Sports Store 6 Ft 2 $60.00

External Insulative Vest Fabric Under Armor Warm Sports Store 6 Ft 2 $80.00

D8102 TC TPE (Tubing) TPE Elastomer Cool Polymers 300 $0.00

Velcro Straps Velcro Crafts Store 6 $12.00Conductive Gel Thermal Grease Noctua NT-H1 2 $20.00

Charging Circuit - - 1 -

Sensing/Operating Circuit Thermocouples/circuit Custom Circuit Boards 1 -

Total Cost $699.00

Vest Bill of Materials


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Material Density Price/lb Price/Vol

Aluminum 6060 T6 0.965 1.1 1.0615

Copper c10100 0.323 3.3 1.0659

Polypropolene Foam 0.0011 0.9 0.00099

D8102 TC TPE (Tubing) 0.0452 5 0.226

Component Material/Type Vendor Volume/Quantity Price

Thermocouples Body Sensing - 6 $80.00

Data Acquisistion software Supplied - 1 -

Vest Sports cooling Vest Veskimo 1 $363.34

Ice - - 4 $8.00

Trash Bags - - 2 $1.00

Total Cost $452.34

Test #1 Bill of Materials

Component Material/Type Vendor Volume/Quantit PriceThermocouples Type K,J - 4 $80.00


Ice - - 4 $8.00

Heater Submersible 150 W Visi-Therm 1 $20.00

Tubing Standard Tubing Home Depot 5 $30.00

Water Pump 728310 Sub EcoPlus 2 $45.00

Alumium Cylinder 6060 T6 - - $40.00

Water Tight Connectons Neoprene Home Depot 4 $10.00

Buckets Standard Paint Bucket Home Depot 2 $5.00

Total Cost $238.00


Component Material/Type Vendor Volume/Quantit Price

Thermocouples Type K,J - 6 $80.00


Aluminum Block 6060 T6 - - $60.00

Thernoelectic Module Standard Single Custom Thermoelectric 1 $30.00

Total Cost $170.00



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Component Material/Type Vendor Volume/Quantity Price

Alumium Cylinder 6060 T6 - - $40.00

Water Pump Standard 25 W EcoPlus 1 $26.00

Water Tight Connectons Neoprene Home Depot 2 $5.00

Tubing TPE Elastomer Cool Polymers 300 $67.80

Buckets Standard Paint Bucket Home Depot 1 $2.50

Heater Submersible 150 W Visi-Therm 1 $20.00

Thermocouples Type K,J - 6 $80.00


Under Armor Cool Armor Sports Store 6 ft 2 $80.00

Under Armor Warm Armor Sports Store 6 ft 2 $80.00

Ice - - 4 $8.00

Total Cost $409.30


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