## Definitions and Notes

## Thermoelectric Coolers

Parameter | Description | Notes |
---|---|---|

ΔTmax | Maximum temperature difference at I=Imax | ΔTmax rated at Qmax=0, at other Q the ΔT should be estimated as ΔT=ΔTmax(1-Q/Qmax) |

Qmax | Maximum heat pumping capacity at I=Imax | Qmax rated at ΔT=0, at other ΔT cooling capacity should be estimated as Q=Qmax(1-ΔT/ΔTmax) |

Imax | Current resulting in greatest ΔTmax | |

Umax | Voltage drop at ΔTmax | |

N | Number of thermocouples (pairs of n- and p-type pellets) | Every thermocouple consists of n-type and p-type pellets |

-xx | Thermoelectric pellet length code | Pellet length is "-xx" x 10 (in mm) |

Th | TEC hot side temperature | Performance data shown in specifications (ΔTmax, Qmax, Imax, Umax) are given for Th=300K |

H | Total TEC height | All dimensions are given in mm. Dimensions A and C are perpendicular to electric wire direction (See drawings at specifications). |

A x B | Cold side dimensions | |

C x D | Hot side dimensions |

## Thermoelectric Generators

Parameter | Description | Notes |
---|---|---|

T _{cold} | Cold side temperature | For specifications it is equal to ambient temperature T_{a}=300K (27 deg.C) |

T _{hot} | Hot side temperature | All specifications are given to three hot side temperatures 35, 55, 85 °C. This provides ΔT 8, 28 and 58 °C, correspondingly |

ΔT | Operation temperature difference | Operation temperature difference between T_{cold} and T_{hot} sides. ΔT=T_{hot}-T_{cold} |

R _{t} | Thermal resistance of TEG | Thermal resistance of TEG in direction perpendicular to cold and hot sides (parallel to heat flux Q through the TEG) |

N | Number of pairs of thermoelements | Number of pairs of thermoelements in the TEG |

R _{teg} | Resistance of TEG | Measured at AC. In Specifications at given ΔT the ACR is given at average temperature between T_{cold} and T_{hot} |

α | Seebeck coefficient | Seebeck coefficient of a pair of thermoelements of the TEG |

Z | Figure-of-Merit of the TEG | It is temperature depending. Typically 2.7-2.9x10^{-3} K^{-1} at T_{a}=300K |

Q | Heat flux through TEG | Total Heat Flux coming through the TEG. Q=ΔT x R_{t} |

U _{oc} | Open circuit voltage | Maximal voltage generated by TEG at given ΔT. Other words it is electromotive force. U_{oc}=N x α x ΔT. |

I _{sc} | Short circuit current | Current at short circuit. I_{sc}=U_{oc}/R_{teg} |

R _{load} | Load resistance | Resistance of external electric scheme which consumes power of TEG |

U _{max} | Maximal output voltage | Maximal output voltage and maximal power are at the equity R_{load}=R_{teg} |

P _{max} | Maximal output power | |

m | Coefficient of optimal electric load | It is given as m=(1+Z (T_{hot}+T_{cold})/2)^0.5 ~ 1.3…1.4 |

R _{opt} | Optimal load resistance | Resistance of electric load which provides maximal efficiency of the TEG. R_{opt}=R_{teg} x m |

n _{opt} | Optimal efficiency of the TEG | Optimal (maximal) efficiency which can provide the TEG at optimal electric load R_{load}=R_{opt} |

U _{out} | Optimal output voltage | The output voltage at maximal efficiency. Optimal voltage is given as U_{out}=U_{oc}/(R_{teg} *(1+m)) |

P _{out} | Optimal output power | Output power generated by the TEG at maximal efficiency P_{out}=U_{out}^2 x R_{opt} |

H | Total TEC height | All dimensions are given in mm. Dimensions A and C are perpendicular to electric wires direction (See drawings at specifications). |

A x B | Hot side dimensions | |

C x D | Cold side dimensions |