At Science Hack Day SF 2013 there was a project to build a thermoelectric cooled cloud chamber. These are some notes about the hardware.

The typical thermoelectric cooler (TEC) will typically produce a maximum temperature difference of 70°C. The amount of heat that can be absorbed is proportional to the current and time.

$$\begin{equation}\dot Q = k_PI\end{equation}$$where $\dot Q$ is heat flow rate, $k_P$ is the Peltier coefficient of the TEC, and $I$ is the current.

So for a given heat rate and a known TEC we can guess the electrical power requirements.

$$\begin{equation}I = \frac{\dot Q}{k_P}\end{equation}$$$$\begin{align} P &= IV \nonumber \\\ &= \frac{V\dot Q}{k_P} \end{align}$$We can computer how big of a power supply we need for each TEC:

In [1]:

```
# Define TECs
TEC_12 = {
'v': 12, # 12 volt version, TEC1-12710
'kp': 9.6, # pelter coef
}
TEC_5 = {
'v': 5, # 5 volt version
'kp': 9.6, # pelter coef
}
# calc power
def power(Q, tec):
v = tec['v']
k = tec['kp']
return (v*Q)/k
```

In [2]:

```
print "Power supply for bottom TEC: ", power(90, TEC_12), ' Watts'
print "Power supply for top TEC ", power(90, TEC_5), 'Watts'
```

Luckily we have two ~100 watt power supplies.