TEC

=//TEC//=

This is the TEC homepage, welcome! Members: Jon Savarese, Annie Becerra and Brent Higgins


 * Function/Goals/problem we're addressing:** As the TEC group, our primary function is working with the actual TEC's(Thermoelectric coolers). These are essentially two metal plates connected together, and when a current is run between them, the TEC can produce heat on one side, and cold on another side, this is known as the peltier effect.

http://en.wikipedia.org/wiki/File:Thermoelectric_Cooler_Diagram.svg



http://www.electronics-cooling.com/1996/09/an-introduction-to-thermoelectric-coolers/

These diagrams show examples of the current running through the TEC, with the cool side being generated, and the dissipated heat on the outer surface of the skin. The second diagram shows the use of conductors and semi-conductors in the TEC device.

Our objective is to design an autonomous system that can regulate a person's core body temperature. We do this through the use of TEC's. By applying this small device in tandem with a heat sink, it is possible to cool the tissue of the human body and regulate their core body temperature, this function can be applies to stroke victims, and a number of digital health issues. The heat sinks are used to dissipate heat from the hot side of the TEC and provide cooling to the component.For our purposes, we will be using several TEC's strategically placed around major arteries to cool the human body down, making sure the body doesn't heat up too much, or cool down too much(hypothermia). The heat sink we are using is made of aluminum with a painted coating and we have a fan sitting on top (Blue) of it to provide cooling. A picture of the heat sink and a TEC is shown below. By applying thermal paste onto the TEC and then placing the heat sink on top, it increases the surface area of the air to aluminum contact.




 * Other groups and us:** Because of the complexity of the project we are trying to accomplish, it is is important to have good communication between the groups. There is a certain flow of information that needs to be maintained among the separate groups working on this project. Our TEC group needs to provide TEC specifications such as dimensions, Qmax(The maximum heat that can be produced), Vmax(Maximum voltage across the plates), dTmax(the maximum temperature difference), how much power the TEC takes to operate and the Coefficient of performance which is the amount of heat one gets for each unit of power supplied. Conversely, the other groups needs to convey their information to us so we can define the correct parameters for the TEC. The research group needs to provide us with heat information regarding the human body, including how well we conduct heat and temperatures the human body can withstand. The power group needs to tell us the possible voltages and maximum power we can be supplied with so we know what specs to look for in TECs.


 * Work up to date:** Up until now, we have worked with the other groups in researching and choosing a TEC, programming and testing the TEC and collecting data for it's cooling capabilities. We originally considered a round TEC with specs involving a 66V source, but eventually ended up choosing a square 40mm x 40mm TEC because of the cheaper price and the operating wattage of 77W, we were able to maximize cooling surface area using this and a medium such as water copper or aluminum. Still left to do in this project is continue testing the TEC at different voltages and measuring the temperature changes at different points on the body including the upper arm, lower arm, core body temperature and fingers. We collect small amounts of data and we still need to test other interfaces to maximize surface area on the skin. Pictured above is one of the TEC's we are using and the one we are currently testing with.

 **"TEC1-12705 Thermoelectric Peltier Cooler 40 mm x 40mm 12V 77 Watt"**  $4.89 Below is a link to the actual TEC we are using manufactured by crazyconn, it has a screenshot of the TEC without the fan: http://www.sawsmiter.com/detail/p_B002UQKEU8/Best-deal-TEC1-12705-Thermoelectric-Peltier-Cooler-40-mm-x-40mm-12V-77-Watt-onsale.html

We bought 6 of these. These TEC's require an operating voltage of only 12V while providing 77W of power, this makes them optimal for the purposes of our project because we need to be able to cool down the core temperature of the body. These TEC's output more power than the previous ones considered for a low operating voltage, making them more efficient for project purposes. We originally considered a round TEC with a low voltage a low power but chose the model we did because it can cool faster and the cooling can reach deeper tissue which is the goal of this project. The original one considered can be found here: http://www.kryotherm.ru/modulez/down.phtml?filename=/dir2attz/import/TB-38-1.0-1.5CHR.pdf. The high wattage on the TEC's creates optimal settings for heat transfer because it makes them cool faster. The TEC has a fan sitting on top of it to absorb the heat so the TEC doesn't reach static equilibrium and stop cooling. The TEC is controlled using the arduino lilypad as a microcontroller that can read and control TEC output and a mosfet switch.

The lilypad is run on a lithium ion battery and operates the TEC's using the mosfet control switch to regulate power and create a controlled testing environment for the TEC. Full details on the specs and operating capabilities of the mosfet switch and the arduino lilypad can be found on the programming and power pages.

The CPU fan we bought is used in conjunction with a heat sink to absorb the heat and keep the TEC from reaching equilibrium and continue cooling. If the heat sink did not exist, the TEC would reach an equilibrium point where the cooling would be balanced out by the heating on the opposite side, the TEC would be in equilibrium and the cooling would stop. To counteract this, we use a fan in conjunction with a heat sink to absorb the heat and remove it to keep the TEC running:

For more information on the data collected, visit the research page.

**Link to data Shee **t- [] This fan is manufactured by dynatron corp

//Add to your report links to the manufacturers' sites as well as brochures that contain the thermoelectric that you talked about in your report. Check eBay, check Amazon, check Alibaba, check Google! Remember to document your research.//

//John Savarese - Research x3 thermoelectric coolers, report back with specifications like how many thermocouples does that particular thermoelectric contain, what is the size of that manufacturer's thermocouples, what is the seedback coefficient of that thermoelectric, how much power does that thermoelectric need?// //+++++++++++++++++++++++++++++++++//

//Okay, I was asked to find TEC specs for a 40x40mm TEC, I found one at a website that has the information listed. It costs $15, has 127 thermocouples. I've also found that most TEC's are rated on 4 components, Vmax(most efficient voltage), Qmax(maximum heat load transferred form cold side to hot side), Imax(most efficient current) and Tmax(most efficient temperature difference between the hot side and the cold side. The one I found online://

http://www.sparkfun.com/products/10080

this one has values : Qmax: 62.2W, Vmax: 15.4V, Imax: 7A, Tmax: 69 degrees C.

It is also suggested that you use a heat sink to remove the heat from the hot side of the device so the TEC doesn't reach stasis and do nothing.

The very same website also gives an example of a sample arduino code used for programming: http://sparkfun.com/datasheets/Components/General/Peltier_Testing.pde -

//Annie Becerra -// //Research x3 thermoelectric coolers, report back with specifications like how many thermocouples does that particular thermoelectric contain, what is the size of that manufacturer's thermocouples, what is the seedback coefficient of that thermoelectric, how much power does that thermoelectric need?//



// That diagrammed disk TEC is tiny. I like that they have discounts if we order more. Lets see how the price of these compares with the price of the disk TECs made by Kryotherm USA. The nice part about the center hole is that temp measurements can be taken and we can get a really good idea of how well the TEC is performing in terms of cooling perfusion. // ||  http://www.tetech.com/Peltier-Thermoelectric-Cooler-Modules/Round-Center-Hole/CH-21-1.0-1.3.html
 * < == **CH-21-1.0-1.3** == ||
 * < **$22.70** ||~ Quantity ||~ Price ||
 * < 1 - 9 ||< $22.70 ||
 * < 10 - 24 ||< $20.10 ||
 * < 25 - 99 ||< $19.40 ||
 * < 100+ ||< CALL ||  ||
 * < 100+ ||< CALL ||  ||


 * <  ||< Imax ||< 3.6 amp(s) ||
 * < Qmax ||< 5.2 watt(s) ||
 * < Vmax ||< 2.4 volt(s) ||
 * < DT max ||< 69 Th=300K ||
 * < OD ||< 15 mm ||
 * < ID ||< 3 mm ||
 * < H ||< 3.6 mm ||  ||
 * < [[image:http://www.tetech.com/temodules/homeimages/center-mainpage.jpg caption="Standard Modules"]] ||< [[image:http://www.tetech.com/temodules/homeimages/center-mainpage2.gif caption="Standard Modules"]] ||


 * < == **CH-41-1.0-0.8** == ||
 * < **$22.10** ||~ Quantity ||~ Price ||
 * < 1 - 9 ||< $22.10 ||
 * < 10 - 24 ||< $19.50 ||
 * < 25 - 99 ||< $18.80 ||
 * < 100+ ||< CALL ||  ||
 * < 100+ ||< CALL ||  ||

http://www.tetech.com/Peltier-Thermoelectric-Cooler-Modules/Rectangle-w-Center-Hole/CH-43-1.0-0.8.html
 * <  ||||< ** Parameters of Category: Rectangular Modules with Center Holes ** ||
 * < Imax ||< 5.7 amp(s) ||
 * < Qmax ||< 18.6 watt(s) ||
 * < Vmax ||< 5.3 volt(s) ||
 * < DT max ||< 68 Th=300K ||
 * < A ||< 22.5 mm ||
 * < B ||< 17.5 mm ||
 * < ID ||< 9.5 mm ||
 * < H ||< 3.1 mm ||  ||

http://www.efunda.com/designstandards/sensors/thermocouples/thmcple_theory.cfm?Orderby=Seebeck0C#Sensitivity
 * ||
 * [[image:http://www.efunda.com/images/section_bar.gif]] ||
 * The Seebeck coefficients (thermoelectric sensitivities) of some common materials at 0 °C (32 °F) are listed in the following table. || [|**Material**] || [|**SeebeckCoeff.**] *  ||   || [|**Material**] ||  [|**SeebeckCoeff.**] *  ||   || [|**Material**] ||  [|**SeebeckCoeff.**] *  ||
 * Bismuth || -72 ||  || Aluminum || 3.5 ||   || Tungsten || 7.5 ||
 * Constantan || -35 ||  || Lead || 4.0 ||   || Iron || 19 ||
 * Nickel || -15 ||  || Tantalum || 4.5 ||   || Nichrome || 25 ||
 * Potassium || -9.0 ||  || Rhodium || 6.0 ||   || Antimony || 47 ||
 * Sodium || -2.0 ||  || Copper || 6.5 ||   || Germanium || 300 ||
 * Platinum || 0 ||  || Gold || 6.5 ||   || Silicon || 440 ||
 * Mercury || 0.60 ||  || Silver || 6.5 ||   || Tellurium || 500 ||
 * Carbon || 3.0 ||  || Cadmium || 7.5 ||   || Selenium || 900 ||
 * * : Units are µV/°C; all data provided at a temperature of 0 °C (32 °F) ||  ||
 * The above table also reveals some possible wire pairings. For instance, iron or copper can be put on the positive terminal while constantan can be used for the negative terminal of a thermocouple circuit (Type J and T). ||
 * The above table also reveals some possible wire pairings. For instance, iron or copper can be put on the positive terminal while constantan can be used for the negative terminal of a thermocouple circuit (Type J and T). ||

//--//

//Brent Higgins -// //Research x3 thermoelectric coolers, report back with specifications like how many thermocouples does that particular thermoelectric contain, what is the size of that manufacturer's thermocouples, what is the seedback coefficient of that thermoelectric, how much power does that thermoelectric need?//

//Round Thermoelectric Cooler//

//Manufacturer: Kryotherm//

Thermoelectric MODULE TB-38-1.0-1.5CH

//Specifications:// []

//Rectangular Thermoelectric Cooler//

//Manufacturer: Kryotherm//

Thermoelectric MODULE TB-35-0.6-0.8

//Specification:// []

//Round Thermoelectric Cooler//

//Manufacturer: Kryotherm//

Thermoelectric MODULE TB-43-1.0-0.8CH

//Specification:// []