# Peltier Cooling Module Data sheet understanding

Discussion in 'General Electronics Discussion' started by Banshee, Oct 21, 2015.

1. ### Banshee

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Oct 18, 2015
Hello everyone

I am working on a project which envolves the implementation of Peltier modules. I am a mechanical engineering student. Currently, I am dealing with a Peltier cooling Module whose data sheet is shown below in the link from Farnell UK. We have Peltier cooling modules in the project which are supposed to cool down some flowing air.
http://www.farnell.com/datasheets/1693164.pdf

1-
I would like to ask about any good books available on the Thermo-electric effect, and more particularly Peltier modules, the physics behind them, mathematical models of them and their implementation.

2-
Also I would like to ask about the performance graph of the Peltier module (see the link below). According to what I understood from the explanation available on the Internet, the Pc notation on the graph refers to the cooling power. Is it the rate at which heat energy is absorbed on the cold side ??

3-
There is a heat little heat exchanger which consists of a heat sink, which holes filled in it and pipes are connected to flow water through the heat sink to increase the convective heat loss and prevent any overheat. While Tc the temperature on the cold side, can Th be considered as the ambient temperature ?

http://oi57.tinypic.com/34hj2m8.jpg

4-
On the performance graph, the "Th" at which the data in the graphs were collected is noted to be 25 C. Does this mean that I can refer to the graphs only in case that that the temperature on the hot side at that temperature ??

This because I found some sources on the Internet claiming at an offset of ±10 C, with a slight margin of error.

5-
The other thing I need to understand is that if my understanding of the cooling power "Pc", and if the temperature on the hot side "Th" remains constant as shown on the graph, for a given value of current as shown with the ascending lines on the right side in the lower section of the graph, why would the cooling power (the power absrobed on the cold side) fall if the temperature on the cold side falls as well. If my understanding of the cooling power is correct, then wouldn't the temperature of the cold side drop as more power "Pc" is absrobed ??

6-
In the lower section of the graph, if I choose two different intersection points on the straight line of the current value 4.8 Amp, when at "Tc = -20 C & Pc = 40 W" and when at "Tc = -5 C & Pc = 60 W", the corresponding temperature differential "dT" between "Tc" and "Th" is "45 C" and "30 C" in relation to the "Th" shown on the graph respectively. Thus, on the upper section of the graph, on the current line of 4.8 Amp, the intersection of the line with "dT= 45 C" & "dT= 30 C", yields voltage values of "V= 24.5 volts" & "V=23.5 volts" respectively. How can the same amount of current, and slight difference in voltage create a substantial difference in the temperature on the cold side ??

7-
How can I start with the implementation of the Peltier module, as I need a starting point. According to what I understood, I need to specify the temperatures I need on both sides of the module, with the cooling power (the power to be absorbed on the cold side, if my understanding of the cooling power shown on the graph is correct), so that I can specify the electric current value I need. Based on the temperature differetial between the hot and the cold side, and the value of the current, I can then determine the value of voltage I need to supply to the Peltier module, so that it generates the difference in temperature I need. Am I on the right track, and is there any piece of advise that I can make use of ??

Sorry for the very long thread, as this is the first time I encounter Peltier modules.  