गुरुवार, 5 दिसंबर 2013

Now, wear ‘AC’ on your wrist to keep body cool

अक्सर पब्लिक प्लेस पर किसी कॉन्फरेंस हाल या ऑडिटोरियम में किसी को ठंड लगती है तो किसी को गर्मी। हरेक व्यक्ति की ताप -गर्मी-ठंडी  सहने की क्षमता अलग अलग रहती है। कोई एक तापमान और आद्रता सबके अनुकूल नहीं रहती है। 

तापानूकलन  संयंत्र ये दो ही काम करते हैं हवा में नमी और हवा के तापमान का विनियमन करते हैं। अब अगर यही काम एक तापविद्युत् रिस्ट बैंड करने लगे तो वह सही मायने में आपका फ्रेंडशिप बैंड  बन जाएगा। 

मैसाच्युसेट्स प्रोद्योगिकी संस्थान के वर्त्तमान और पूर्व छात्रों की एक टोली ने एक ऐसा ही पहनने लायक तापनुकूलंन  संयंत्र तैयार कर लिया है। यह युक्ति आपकी  चमड़ी और हवा का तापमान भांप कर तदानुसार गर्म या ठंडी वेव-फ्रंट (स्पंदन )चमड़ी को देगी जो प्रति सेकिंड ०. ४ सेल्सियस तापमान में तबदीली ला सकेंगी । पांच सेकिंड तक इसे चालु करके फिर १० मिनिट का विराम दिया जा सकता है। अपने ज़रुरत के  मुताबिक़ आप अपने शरीर का तापमान इस थर्मोइलेक्ट्रिक रिस्ट बैंड के ज़रिये बनाये  रख सकते हैं। 

जब हम दो विभिन्न धातुओं के तारों के सिरों को जोड़कर एक  परिपथ (closed loop )बना लेते हैं तथा एक सिरे को यदि बर्फ में दबाके दूसरे को गर्मी पहुंचाते चले जाएँ तब दोनों जंक्शनों (जोड़ों )के बीच एक तापान्तर देखा जाता है । इसे तापविद्युत प्रभाव कहा जाता है। 

इसका विलोम यह है कि यदि इस परिपथ में बिजली (इलेक्ट्रिक करेंट )भेजा जाए तब एक जंक्शन पर ऊष्मा विसर्जित-उत्सर्जित  होगी दूसरे पर अव -शोषित। 

एक ताप नियामक के रूप में इस साधारण से लगने वाले प्रभाव का इस्तेमाल किया जाता है। आपके फ्रिज में भी एक ऐसा ही थर्मोस्टेट लगा होता है जो स्वयं  चालित रहता है। 

Wristify: Thermal Comfort via a Wrist Band

Can’t get the room temperature just right? Whether you are wrangling with your family or workmates, getting a comfortable environment can be difficult. And expensive—building heating and cooling amount to some 16.5 percent of U.S. primary energy consumption.

A team of MIT students and alumni has a new low-cost solution: Wristify, a wrist cuff that allows individuals to maintain a comfortable body temperature independent of their environment. In essence, their thermoelectric bracelet monitors air and skin temperature and then responds with pulses of hot or cold waveforms to the wrist.

How did the Wristify team make the key discovery that human skin is very sensitive to minute, rapid changes in temperature, which affect the whole body.

We first made the discovery from using our prototype. In particular, Matt Smith noticed that the device was more comfortable when using it in a manual pulsing mode, switching it on and off at controlled intervals. We all tried the bracelet in this mode and agreed with Matt’s discovery. This led to the literature review on human thermal perception and the finding that supported that discovery, which in turn led us to incorporate automatic pulsing into the prototype.

Now, wear ‘AC’ on your wrist to keep body cool

WASHINGTON: Four engineering students have developed a prototype wearable device which can cool the body, making air conditioning obsolete.

The device developed by the MIT students, 'Wristify' , leverages the physical phenomenon known as the Peltier effect to reduce the body temperature, Fox News reported . Wristify is a series of junctions of two different conductors , called a Peltier cooler , which is powered by a small battery and is attached to a wrist strap.

When the device is placed against the skin, it makes you feel cooler by reducing the temperature of your wrist by a few fractions of a degree per second for a couple of seconds at a time. The team which is developing the device is still tinkering with it to figure out the optimal cooling cycle, but at this stage, they say the most effective method is to cool the wrist by 0.4 degrees Celsius (0.7F) per second for five seconds, and then turn off for 10 seconds.

The chief benefit of this device is that it offers a more personalized approach to temperature control.

Just Imagine a World In Which the Room Temp Is Fine With Everyone

What's the number one complaint heard by most meeting planners while on site? I'm guessing it might well be that the room is too hot or too cold—or probably both at the same time, according to different attendees. Yes, the thermostat is as highly contentious an item in the ballroom as it is in the office (and in many of our homes), where some like it hot and others, not.

So how exciting is it to hear about a newwearable thermoelectric bracelet that would allow every one of those thin-skinned/hot-flashing/cold-blooded attendees to adjust the temperature exactly to their liking without you having to do a thing? A team of those crazy kids at MIT have come up with just such a device, the Wristify, which earned them $10,000 and the top prize in MIT's Making and Designing Materials Engineering Competition. And it may end up making them a whole lot more, too, if they can make it a little less clunky (at least as innocuous as my FitBit Flex would be nice). And think of how much energy hotels, convention centers, and other meetings spaces could save as well.


(Physics / General Physics) Physics the production of heat at one junction and the absorption of heat at the other junction of a thermocouple when a current is passed around the thermocouple circuit. The heat produced is additional to the heat arising from the resistance of the wires Compare Seebeck effect

"What is this Peltier Effect thing that some fridges use for cooling?", 

The Peltier Effect is just the Thermocouple Effect working backwards. Suppose you get a wire of copper, and another wire made of iron, and join them together at each end (the joiny bits). If you put one junction (the joiny bit) in iced water, and the other end in boiling water, an electrical current will flow in the wires. 

So, if you have a loop made of two different metals, a change of temperature will make electricity. It also goes backwards - electricity will make a change of temperature. 

This was discovered in 1834, by John-Charles-Athanase Peltier, a French clock maker who retired when he was 30 years old. He spent the rest of his life investigating scientific phenomena such as the boiling point of water at high altitudes, electricity in the atmosphere, and water spouts. 

In one experiment, Peltier joined a piece of copper wire, to a piece of bismuth wire, to a battery, and then completed the loop back to the copper wire. When he switched on the battery, one of the copper-bismuth junctions got hot, and the other one got cold. 

If you put the cold end inside a box and then insulate that box, well, sonny-boy, you've got yourself a refrigerator. The disadvantage of the Peltier Effect refrigerator is that it's not very powerful, nor is it very efficient, but it is very reliable, because it has no moving parts. 

What is a Thermocouple?
A Thermocouple is a sensor used to measure temperature. Thermocouples consist of two wire legs made from different metals. The wires legs are welded together at one end, creating a junction. This junction is where the temperature is measured. When the junction experiences a change in temperature, a voltage is created. The voltage can then be interpreted using thermocouple reference tables (linked) to calculate the temperature. 


Just Imagine a World In Which the Room Temp Is Fine With Everyone

Meetings Net (blog)-by Sue Pelletier-Nov 25, 2013Share
A team of those crazy kids at MIT have come up with just such a device, the Wristify, which earned them $10,000 and the top prize in MIT's ...


  1. Wristify: New Wristband Keeps Your Body at the Perfect Temperature

    Nov 3, 2013
    Get Latest health news and headlines from weather.com A wristband developed by MIT students, called ...

The Wristy thermoelectric bracelet

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