Member #549694

Member Since: April 28, 2014

Country: United States

  • I know this is an old post, but for you hackers doing an alcohol related project, Drinking Alcohol (ethyl alcohol) actually has a specific heat of 2.46 kJ/(kg * K) , where water (H20) has a specific heat of about 4.18 kJ/(kg * K). What this means is that the higher the alcohol content, the less energy it takes to heat (or cool) said volume of liquid.

    Also, According to The density of ethyl alcohol is 785.1 Kg/m3, where as water’s density is generally defined as ~1000 kg/m3.

    So to find the actual specific heat of the beverage, with known alcohol content, use this formula.

    C = (2.46 * (%Alc)) + (4.18 * (1 - %Alc)) Where C = specific heat of liquid beverage %Alc = Percent of alcohol per volume in beverage (ex: If your beverage is 5% alchohol by volume, you would use the number .05 in your calculation)

    I am not going to poke at the mass change atm.

    I’ll Post again at the end of the semester (End of May 2015) with the rest of the calculations necessary to accurately calculate the cooling with this specific cooler once I finish thermodynamics. Good luck! -JT-

  • I went poking around… Super Capacitors have pretty lousy tolerances generally. I struggled to find a supercap with +- 10% tolerance (they are rare but they are out there.)

  • These would be dangerous to pop though. Because their pop could be a fireball, or shrapnel flying around the room.

  • That is actually a fantastic idea! Probably could hack the case by 3D printing a battery holder that does just that… And have the contacts so the extra weight would not unbalance the iron at all. Especially because the cartridge setup, this would not be too difficult…

  • Will these come in an electrostatic version?

  • These devices generally have a MT-BF (mean time between failure) of about 10000 hrs from what I’ve read.

    As to it falling, if you put it on a flat stationary surface the device shouldn’t fall over. I suggest glue if you have further gravitational concerns.

  • Silicone. Like the caulk used to keep moisture out.

    Cant ever remember there is a difference.. Gets me every time… sorry about the ambiguity folks.

  • Is this why when I use a basic circuit (connected, on and off doesnt matter) My finger can cause it to switch on and off unintentionally??

  • From cross product investigation, generally the side seals are made from silicon.

  • I used If i remember 5AA Ni-MH batteries and this thing became very cool. I did not want to touch it. Hot end became very very hot. Putting some mafths into this Ni-MH = 1.2V nominal. The batteries had a rated capacity of 2400mAh. I had 2 wells of them, and it ran for an hour with 2 5V fans attached to it. That is 1.2V x (2.4A x 2) = 6.9W of power put into it. It maintained a small Styrofoam’s internal air temperature, and slowed the rate at which the ice inside was melting. Later, I hooked this up to 10 Ni-MH batteries and it got cold and hot so fast it was crazy. Make sure to heat sink/fan the hot side if you are using this to cool. Its power is based off of its potential to create temperature gradients.

    Experience and Summary: This thing runs at 5V. It probably can Run at lower voltages. It will draw as much current as you let it. The more voltage you let it have, The bigger temperature difference it can achieve. The more amperes you feed it, the faster it can achieve that difference.

No public wish lists :(