The Peltier module can be used in 4 different schemes: as a heating element (in incubators...), as a cooling element (in refrigerators...), to generate electricity (generator...), and also using the Peltier element you can generate water . This is what my article will be about.

Peltier element is a thermoelectric converter, the operating principle of which is based on the Peltier effect - the occurrence of a temperature difference when an electric current flows. In English-language literature, Peltier elements are designated TEC (from the English Thermoelectric Cooler - thermoelectric cooler).

The opposite effect of the Peltier effect is called the Seebeck effect.

Operating principle

The operation of Peltier elements is based on the contact of two conductive materials with different electron energy levels in the conduction band. When current flows through the contact of such materials, the electron must acquire energy in order to move to a higher energy conduction band of another semiconductor. When this energy is absorbed, the contact point between the semiconductors cools. When current flows in the opposite direction, the contact point between the semiconductors heats up, in addition to the usual thermal effect.

When metals come into contact, the Peltier effect is so small that it is unnoticeable against the background of ohmic heating and thermal conductivity phenomena. Therefore, in practical applications, contact between two semiconductors is used.

A Peltier element consists of one or more pairs of small semiconductor parallelepipeds - one n-type and one p-type in a pair (usually bismuth telluride, Bi2Te3 and silicon germanide), which are connected in pairs using metal bridges. Metal jumpers simultaneously serve as thermal contacts and are insulated with a non-conductive film or ceramic plate. Pairs of parallelepipeds are connected in such a way that a series connection of many pairs of semiconductors with different types of conductivity is formed, so that at the top there are one sequence of connections (n->p), and at the bottom opposite (p->n). Electric current flows sequentially through all parallelepipeds. Depending on the direction of the current, the upper contacts are cooled and the lower ones are heated - or vice versa. Thus, electric current transfers heat from one side of the Peltier element to the opposite and creates a temperature difference.

If you cool the heating side of the Peltier element, for example using a radiator and fan, then the temperature of the cold side becomes even lower. In single-stage elements, depending on the element type and current value, the temperature difference can reach approximately 70 °C.

Advantages and disadvantages

The advantage of the Peltier element is its small size, the absence of any moving parts, as well as gases and liquids. By reversing the direction of the current, both cooling and heating are possible - this makes it possible to thermostat at ambient temperatures both above and below the thermostat temperature. Another advantage is the absence of mechanical parts and the absence of noise.

The disadvantage of the Peltier element is its lower efficiency than that of compressor refrigeration units using freon, which leads to high power consumption to achieve a noticeable temperature difference. Despite this, developments are underway to increase thermal efficiency, and Peltier elements have found wide application in technology, since temperatures below 0 °C can be achieved without any additional devices.

The main problem in constructing Peltier elements with high efficiency is that free electrons in a substance are simultaneously carriers of both electric current and heat. The material for the Peltier element must simultaneously have two mutually exclusive properties - it conducts electric current well, but poorly conducts heat.

In Peltier cell batteries, it is possible to achieve a theoretically very large temperature difference, more than 70 degrees Celsius, therefore it is better to use a pulsed temperature control method, thanks to which energy consumption can also be reduced. In this case, it is desirable to smooth out current ripples to extend the service life of the Peltier element.

Application of Thermoelectric Module: in water coolers, cooling systems for computers or microcircuits of various small-sized devices, in electric thermal generators, cooling of video cards, north or south bridges, car refrigerators, air coolers, Arduino, for cooling CCD matrices and infrared photodetectors, in electric thermal generators, in thermostats, in scientific laboratory instruments, thermal calibrators, thermal stabilizers. In general, where it is required to achieve temperature differences of more than 60 degrees.

Peltier plate dimensions and consumption characteristics

Dimensions of Peltier plates and consumption characteristics (power consumption, voltage, current, maximum temperature difference). The markings of these thermoelectric generators may be different on different sites, it all depends on the manufacturer (for example: TEG1-241-1.4-1.2; CP1.4-127-06L domestic; TB-127-1.4-1.5 Frost-72; SP1848-27145; Seebeck thermogenerator TEP1-142T300). The characteristics, in turn, will not differ much, but some indicators do not differ significantly.

Qmax	Umax	Imax	dTmax	Dimensions, (mm)
(W)	(IN)	(A)	(hail)	A	B	H
36,0	16,1	3,6	71	30,0	30,0	3,6
36,0	16,1	3,6	71	40,0	40,0	3,6
62,0	16,3	6,2	72	40,0	40,0	3,9
65,0	16,7	6,3	74	40,0	40,0	3,9
80,0	16,1	8,0	71	40,0	40,0	3,4
80,0	16,1	8,0	71	48,0	48,0	3,4
94,0	24,9	6,1	70	40,0	40,0	3,9
115,0	24,6	7,6	69	40,0	40,0	3,6
120,0	24,6	7,9	69	40,0	40,0	3,4
131,0	24,6	8,6	69	40,0	40,0	3,3
172,0	24,6	11,3	69	40,0	40,0	3,2
156,0	15,7	16,1	70	48,0	48,0	3,4
223,0	15,5	23,4	68	55,0	59,0	3,3
310,0	24,6	20,6	69	62,0	62,0	3,2

DIY USB Refrigerator (Peltier Module)

To build our mini-fridge, we need to find or buy a Peltier element (you can read what it is and how it works below) and two radiators.

This very Peltier element, I tore it out of a broken computer, it stood there between the processor and the cooler. I cleaned off the old thermal paste from it. In a nutshell, this Peltier element, when DC is supplied to it, begins to work as follows: one side of it begins to heat up, and the other begins to cool; if you change the polarity of the power source, the sides of the element will behave in the opposite way!

Next, I took two massive radiators from an unnecessary amplifier. Then I lubricated the element with new thermal paste, which I bought at a radio store, and clamped the Peltier element between the radiators. The use of thermal paste in this case is mandatory!
I connected the wires to the element from a USB cable and plugged it into the computer - one radiator began to heat up, and the second began to cool down! So, everything is in order!

The material I used to glue the refrigerator together is similar to compressed foam or porous plastic. In general, the material can be anything, its main quality is thermal insulation.
The glass is organic and looks quite fragile, but in fact the material is durable.
Glue - superglue.

Then, for convenience, I made a magnetic clasp.
It turned out fine - a bottle of mineral water could easily fit in there.

Generator - generating electricity using a Peltier element

Pros of this generator:

— Fuel is anything that burns or heats.
— USB output 5 Volt, 500mA.
— Does not depend on the sun, wind, etc.
- Simple and strong design that can last forever.
— You can cook food on it while your phone is charging.
- Versatility.
— Anyone can assemble it at home in 1 evening (even an AvtoVAZ employee =)).
- Cheap design.

I didn’t invent it, there are commercial copies that are much better than mine. For example, BioLite CampStove, its price is 7900 rubles. My copy was made in a hurry for writing this article and further experiments.

The basis is the Peltier element. This is a thermoelectric module used in water coolers and portable refrigerators, and it is also used to cool the processor. When voltage is applied to it, one side cools and the other heats up. On the contrary, we will heat one side to generate electricity.

The main principle is that one side heats up and the other remains unchanged, for maximum efficiency you need a temperature difference of 100 degrees Celsius.

Let's get started!


We will need:
— Peltier element, I used TEC1-12710
- Unnecessary power supply from the computer
Anyone, even the one that burned down, and everything burned out except the body
- Voltage regulator
DC-DC Boost Module, Input voltage 1-5 Volts, output always 5V.
— Radiator (the bigger the better), preferably with a 5V cooler, because The radiator will gradually heat up. In winter this is not a problem, since you can put the radiator on ice.
— Thermal paste
- Set of tools

TEC1-12710 module, rated at 10 A (less or more). But the more powerful ones will be larger. The higher the current, the more efficient and expensive it is. I bought it from Aliexpress for about 250 rubles. In our electronics stores, this costs about 1,500 rubles.

The module is designed for a maximum voltage of 12V, but it does not output that much due to low efficiency when we use it in the opposite direction, i.e. to receive current.

In order for there to be a stable 5 volts and devices to be charged safely, you need a step-up stabilizer. It starts producing 5 Volts when there is still only 1 Volt on the Peltier element. You can know that everything is ready for charging by the lit LED on the module.


You can assemble your own, but I decided to trust the Chinese, they offer a ready-made module with a USB output for 80 rubles. on the same site.

Let's gut our power supply. I had to make additional holes for better air circulation (the power supply was very old).

The main principle is that air is sucked in from below and comes out through the top. Simply put, you need to make a regular stove. Don't forget to provide a hole for throwing wood chips and a stand for a pot or mug for boiling water, if you need it.


Next, you need to attach the Peltier module with a radiator to a flat wall, after first evenly applying thermal paste. The tighter the contact, the better. The side where the model is written is cold, it is to this side that we apply the radiator. If you mix it up, the module will not output voltage; in this case, you just need to swap the wires.


We solder the boost converter and find where to hide it. You can generally leave it hanging on the wires, but you definitely need to insulate it, for example, put heat shrink on it.

Let's put everything together. This is what you should get:

How it works?

We throw branches, wood chips, in general, everything that burns inside. Then we light it up. The fire heats the walls of the stove and the Peltier element, which is on one of these walls. The other side of the element, which is on the radiator, remains at outside temperature. The greater the temperature difference, the greater the power, but don't overdo it.

Maximum efficiency is achieved already with a difference of 100 degrees. Over time, the radiator begins to heat up and will need to be cooled. You can throw snow, pour water on it, place the radiator on ice or in water, or place a mug of cold water on it. There are many options, the simplest is a cooler, it will take away some of the power, but due to cooling the overall result will not change.


DO NOT expose the element to high temperatures, it may burn out and burn out. The documentation indicates a maximum temperature of 180 °C, but there is no need to worry too much, with good cooling and with simple firewood nothing will happen to it.

If you are not lazy and do everything right, you will get such a simple wood chipper on which you can heat food, boil, water and charge your gadgets at the same time.

It can be used at home if there is a power outage by placing a candle inside. By the way, if you connect LEDs to it, the light will be much brighter than from the candle itself.

In any place where you can find something burning, you will have electricity, heat and the ability to conveniently cook food, using less fuel compared to a fire.

First tests!

After work I went into the forest, the sun had almost set, the brushwood was wet, but the stove paid off 100%.

The result exceeded all my expectations. Immediately after the wood chips burned, the indicator came on, I connected the phone and it began to charge. Charging was stable.

The converter didn't strain at all. I also took with me a cooling pad for the laptop, it has 2 coolers and LEDs, it should consume a decent amount. I connected it, everything spins, glows, and the breeze blows. I also took a USB fan and connected it at the end, when there were only coals left. Everything is spinning great, I don’t even know what else to try.

Result:

Everything works great, it gives out its gender Ampere. Still, you need a cooler, because... in half an hour the radiator heated up to about 40 degrees, in the summer it will be even more. Let yourself spin.

The flames shoot high up, I personally don’t need such a fire, I will cover some of the holes so that it burns more slowly.

I will do everything new, I will take as a basis a standard wood chipper that is made from tin cans, but I will make it from thicker metal and rectangular in shape. I’ll buy a good radiator with a cooler of a suitable shape and try to make a collapsible version so that it takes up less space when carrying it.

Producing drinking water using a Peltier module

Peltier elements seem to be nothing new for a long time, but many do not fully understand the principle of their operation, and do not know what can be made from modules and why they are needed. Inventor Igor Beletsky will show several visual experiments so that you have an understanding of what these records are capable of.

They are easy to purchase online and have delivered by mail. The best place to buy Peltier is in this Chinese store. There is also a special cooling cooler.

The most popular among practitioners who are passionate about the ideas of free natural energy and manufacturers of technical devices is an element measuring 40 by 40 millimeters with the marking. This means that it consists of 127 pairs of tiny thermoelements - semiconductors of various types, which are connected in pairs using copper jumpers in a series circuit and are designed for a direct current of up to 5 A at a voltage of 12 volts.

Some people think that Peltier modules are something like solar panels - after all, they are just as flat, wires stick out, and both of them can generate electric current. Alas, this is not entirely true in reality. To understand how the mysterious plates function, watch the video by I. Beletsky, description in text format below.

Pelte and Seebeck effects – module functions

This device has two modes of operation - 1. production of cold and heat; 2 – generation of electric current.

1. So, famous Peltier effect(heat and cold). This is when you apply direct current to an element and notice that one side of it becomes warmer and the other colder. Thus it works like a heat pump. A very useful feature. No doubt about it.

2. But it turned out that the reverse process also takes place - the so-called Seebeck effect, namely the occurrence of an electric current when a certain temperature difference is established and maintained on the sides of the module (plate) itself.

Note. Never overheat the elements if you want to continue experimenting with them. The semiconductors in the module are soldered with solder, the melting point of which can range from eighty to two hundred degrees. And considering where most of these elements are produced today, one can only guess on what snot they were soldered together.

Scheme. How electricity is created by heating Peltier sides

The trouble is that this element will only work normally with effective cooling.

Electricity Test

For example, we want to test the Zebeck effect. Place a mug of boiling water on top. Thus, the 100 degrees permissible heating temperature is not exceeded.

We observe the appearance of tension. Interestingly, if you change the direction of heat flow through the module, the direction of the DC current will change. But over time, on the second side, due to the thermal conductivity of the Peltier element, the temperature will also rise and the voltage, naturally, will drop.

For the effect to be permanent, constant heat removal is needed. To do this, the module is placed on a massive radiator and preferably with active cooling. The indicators are clearly better, as you understand. This requires additional energy consumption.

Let's say you want to make a travel charger for mobile phones from this element. Then, in nature, the radiator can be placed in cold water, perhaps even running water or ice, which is undoubtedly even better. The use of these modules in winter with a good free minus is the most promising.

True, one element for charging the phone will clearly not be enough. But two is better. Naturally, if you increase the heating, the output power will also increase. But this is a very risky step that can only be taken for the sake of experiment. The operation of such a generator will not last long.

Now let's move on to the Peltier effect, that is, to the production of cold.

Refrigerator on Pelte modules - how effective is it?

A car refrigerator will be used for the experiment. Its useful volume is 20 liters. Please note - the declared power is 48 watts at a current of 4 amperes and a constant voltage of 12 volts. This means that there is only 1 small Peltier element inside. For those who are not in the know, let us tell you a secret - the same power has an ordinary home refrigerator, the size of which is many times larger. Well, okay, not about that now. Let's check its effectiveness. For example, let’s set him the minimum task of cooling a glass of water at room temperature 26 degrees. To operate the refrigerator, we will use a power supply that is ideally suited to its parameters. Additionally, we will place a wattmeter in the circuit. It will display current, voltage and power in real time. But the most important thing is consumption, the so-called watts per hour. This way we can roughly estimate the energy consumption of our refrigerator.

We turn it on and see, everything works great. Here is the current 4.29 A. Voltage 11.15 Volts. Power 47.9 Watt. 0.1 Watt-hours.

While the process is ongoing, let’s conduct a more visual experiment that will show what exactly is happening in the refrigerator. When we apply direct current to the element, it will begin to pump heat from one side to the other.

By the way, if you change the direction of the current, the direction of heat transfer will also change, which is very convenient. The main thing is not to forget about active cooling, because fifty watts of electrical power heats the element instantly. The more efficiently we remove heat from the hot side, the colder it is on the other.

As you can see, on the very surface of the module, water freezes very quickly, and it consumes so much energy.

But let's return to our refrigerator. After one hour of work, the air temperature inside dropped to fifteen degrees, and near the water dropped to 20. It was surprising that in an hour of work he consumed exactly 48 watts. After two hours, the air was 13 degrees, and the water was 17. And finally, after three hours of work, the air temperature stopped at 13 degrees, and in a glass of water it was 15 and would not drop below 12. Well, the refrigerator was so-so, considering that it was not completely filled with drinks. But at the same time, this monster consumed 140 watts. For a home network this may not be much, but for a car battery this is already quite noticeable. Therefore, there is only one element here. Because no more battery will simply last. This means that the efficiency of such a module is negligible - literally a few percent, which again depends on the manufacturer. This refrigerator is more like a good thermos. If they took cold food from home, he simply would not allow it to heat up quickly. Making such refrigerators large is energetically unprofitable.

In what cases is Peltier effective?

By the way, this also applies to do-it-yourselfers who are trying to make car air conditioners using this principle. There are more efficient technologies, but using Peltier elements to cool something small and compact is simply the ideal solution. There is a whole range of such devices, for example, to cool processors or microcircuits of various small-sized devices. This is most likely the main advantage of such elements. They are miniature and minimal in weight. Compared to the same photocells, Peltier certainly has more disadvantages, but the effect itself certainly deserves attention. In the end, it all depends on the tasks being solved, and if the energy is free, then high efficiency is not so important.

To how many degrees can the element be cooled? About it .

Conclusion

Peltier modules, popular among radio amateurs and engineers, are electronic elements that are actively used for cooling systems and generating electricity. Based on them, power sources are being developed for lighting or charging devices while traveling, as well as mobile compact refrigerators for cars. There are attempts to use it for cooling computer processors. The operation of the devices is based on 2 mechanisms: when one side of the Peltier plate is heated and the second is cooled, an electric current is generated; When electricity is supplied to the contacts, one side of the plate is cooled, the other is heated.

DIY Peltier element

In English the term is referred to as TEC - thermoelectric cooler. A do-it-yourself Peltier element is a temperature-electric converter that operates on the principle of a temperature difference occurring at the moment an electric current is applied. Is it possible to assemble it yourself and what use can it be used for?

DIY Peltier element

It is almost impossible to make a device at home, especially since it does not make much sense, given its low market value.

But most craftsmen still prefer to make the Peltier element with their own hands, citing a number of its advantages:

1. Compact, easy to install on a homemade electronic plateau.
2. There are no moving parts, which increases its service life.
3. Possibility of connecting several elements in a cascade circuit to reduce very high temperatures.

However, DIY Peltier has certain disadvantages: low efficiency, the need to supply high current to obtain a noticeable temperature difference, and the difficulty of removing thermal energy from the cooled surface.

Let's look at an example of diagrams on how to make a Peltier with your own hands:

• Use it as a part of a thermoelectric generator, according to the connection diagram.
• Assemble a simple converter on the L6920 IC chip (Figure 1).

Figure 1. DIY Peltier element: universal circuit

1. Apply a voltage in the range of 0.8-5.5V to the input of the resulting converter in order to have a stable 5V output.
2. When using a conventional type device, set the temperature limit of the heated side to 150 degrees.
3. For calibration, use a container of boiling water as a heat source, which will definitely not heat up above 100 degrees.

Description of technology and principle of operation

The method of operation of a thermoelectric cooler is quite simple. The DIY Peltier effect is based on the contact of two current conductors that have different levels of electron energy in their conduction zone.

Figure 2. Operating principle of the element

When an electric current is applied through such a bond, the electron acquires high energy, allowing it to move into the higher-energy conduction band of the second semiconductor. When this energy is absorbed, the cooling area of ​​the conductors occurs (Figure 2).

When the process occurs in the opposite direction, the reaction leads to heating of the contact area and the usual thermal effect.

After watching a Peltier video with your own hands, you can draw certain conclusions about the principle of its operation:

1. The amount of current supplied will be proportional to the degree of cooling - if a good heat sink is made on one side of the module, when using radiator circuits, its cold side will ensure the lowest possible temperature.
2. When the polarity of the current changes, the heating and cooling planes change sides.
3. When an object comes into contact with a metal surface, it becomes so small that it cannot be seen against the background of ohmic heating or other thermal conductivity effects, which is why in practice two semiconductors are used.
4. Thanks to a varied number of thermocouples - from 1 to 100, almost any refrigeration capacity can be achieved.

Technical characteristics of the Peltier element

The component is widely used in various refrigeration circuits.

Which is not surprising, since a DIY peltier has the following technical characteristics:

1. Capable of reaching low temperatures, which is an excellent solution for cooling electrical appliances and those equipment subject to heating.
2. It perfectly performs the work of a conventional cooler, which makes it possible to install it in modern sound and acoustic systems.
3. Absolutely silent - during operation it does not produce any extraneous or intense sounds.
4. It has powerful heat transfer while maintaining the desired temperature on the radiator for quite a long time.

Do-it-yourself refrigerator with Peltier elements

To assemble the refrigeration unit you will need a sufficient number of electrical conductors and special tools (Figure 3).

A DIY Peltier refrigerator requires a special approach to assembly and the materials used:

1. The basis for the board should be durable ceramics;
2. For the maximum temperature difference, at least 20 connections must be prepared;
3. Correct calculations are the key to increasing efficiency by 70%;
4. Freon will provide the greatest power to the equipment used;
5. A homemade module is installed near its evaporator, next to the motor;
6. Installation is carried out with a standard set of tools using gaskets;
7. They are necessary to isolate the working model from the starting relay;
8. Insulation will also be needed for the wiring itself, before connecting it to the compressor;
9. To avoid short circuit, the strength of the limiting voltage is called by the tester.

Figure 3. Using a Peltier element, you can easily assemble a camping refrigerator

A similar scheme can be used for a car cooler. The Peltier car refrigerator is assembled with your own hands on a ceramic plate no less than 1 millimeter thick. It uses non-modular copper connections with a capacity of 4A and uses conductors marked “PR20”, suitable for various types of contacts. To connect the device to the capacitor, use a regular soldering iron.

DIY Peltier air conditioner

In this case, only “PR12” type conductors can be used for the product (Figure 4).

Do-it-yourself Peltier air conditioners are assembled only on them, since they can withstand abnormal temperatures and produce voltages up to 23V:

1. Mainly used for cooling computer video cards.
2. Its resistance fluctuates within 3 ohms.
3. The temperature difference is 10 degrees, and the efficiency is 65%.
4. It requires 14 copper conductors.
5. A non-modular adapter is used for connection.
6. The device is mounted next to the built-in cooler on the video card.
7. The structure is secured with metal corners and ordinary nuts.

Figure 4. The element is also used to create portable air conditioners

If strong extraneous noise or other uncharacteristic sounds are noticed during operation of the air conditioner, it is checked for functionality with a multimeter.

DIY Peltier generator

It is not so difficult to assemble such a device yourself. A DIY Peltier generator has its own characteristics: the performance of the assembled device increases by 10% due to greater cooling of the motor, but it is not recommended to heat the main components to over 200 degrees. The device can withstand a maximum load of 30A, and its resistance can be 4 Ohms due to the larger number of conductors (Figure 5).

It is worth remembering that a generator based on Peltier elements with your own hands:

1. It has a temperature deviation in the system of approximately 13 degrees.
2. In most cases of assembly and disassembly of the structure, the stator does not interfere with them.
3. The module is attached directly to the rotor, for which you need to disconnect the central shaft.
4. To avoid heating the rotor winding from the inductor, ceramic plates should be used.

Figure 5. A Peltier element will help create a camping generator

A DIY Peltier heat generator is assembled from two 10*10cm plates, 1mm thick, secured with thermal paste, which cover the four required modules. A tin can or any other container is placed on top of them to ignite the fire, which will provide 170-180 degrees. A copper or aluminum radiator is attached to the bottom of one of the plates with screws. Another 20*12cm plate is attached to it, to which another such part is attached. A factory-made battery casing is installed on it, to which a connector for charging a smartphone is soldered.

DIY Peltier dehumidifier

Unlike the same air conditioner, the implementation of this idea is completely justified. The DIY Peltier dryer has a simple design and low cost, and its cooling module lowers the temperature of the radiator below the dew point, which leads to the deposition of moisture contained in the air passing through the device. Next, the settled water is sent to a special storage tank (Figure 6).

Despite the low efficiency, the efficiency of such a device can be called quite satisfactory.

Do-it-yourself Peltier dehumidifier:

1. It connects without problems - a constant voltage is supplied to the output wires, the value of which is written in its datasheet.
2. It has a standard polarity - the red wire goes to plus, the black wire to minus; if they are mixed up, the cooled and heated surfaces will change places.
3. It is checked tactilely - when connected to a voltage source, one side will be cold, the other will be warm.
4. If there is no current source nearby, we connect the probes to the terminals of the module and bring a lit match or lighter to one of the sides and observe the readings of the device.

Figure 6. Air dryer assembly diagram

How to connect Peltier elements on a module

If we are talking about a simple regulator, there should not be any difficulties in connecting if there is a circuit. A DIY Peltier module consists of two metal plates and wiring with contacts. To install it, “PP” conductors are prepared and placed at the base. To control the temperature regime, semiconductors are used at the output. To assemble all the components together, use a medium-power soldering iron. Lastly, connect the two wires through which the electric current passes.

The DIY Peltier module has the following connection nuances:

1. The first conductive wire is mounted at the lower base of the structure.
2. It is fixed near the outermost conductive link.
3. In this case, you should avoid any contact with a metal part.
4. Next, a second such wiring is attached in the upper part.
5. It is fixed in the same way as the previous one.

Testing a self-assembled Peltier module

Given the ease of assembly, making the device yourself is not difficult. Testing a Peltier element made from diodes with your own hands, like any other, is also not difficult. The main thing at the initial stages is to use the right materials - to prepare two metal plates and wiring with the necessary contacts, semiconductors marked “PP”. You can check everything for serviceability using a multimeter or a regular tester, and the diodes should light up when the device is connected to the network.

The thermocouple (Peltier module) operates on the reverse principle of a thermocouple - the appearance of a temperature difference when electric current flows.

How does the Peltier element work?

It is quite simple to use a Peltier module, the operating principle of which is to release or absorb heat at the moment of contact of different materials when the energy flow of electrons passes through it before and after the contact is different. If it is less at the outlet, it means heat is generated there. When electrons in contact are inhibited by an electric field, they transfer kinetic energy to the crystal lattice, heating it up. If they accelerate, heat is absorbed. This occurs due to the fact that part of the energy is taken from the crystal lattice and it cools.

To a large extent, this phenomenon is inherent in semiconductors, which is explained by the large difference in charges.

The Peltier module, the application of which is the topic of our review, is used in the creation of thermoelectric cooling devices (TECs). The simplest of them consists of two p- and n-type semiconductors connected in series through copper contacts.

If electrons move from a semiconductor "p" to "n", at the first junction with a metal bridge they recombine, releasing energy. The next transition from the semiconductor "p" to the copper conductor is accompanied by the "pulling" of electrons through the contact by an electric field. This process leads to energy absorption and cooling of the area around the contact. Processes occur in a similar way at the following transitions.

By placing heated and cooled contacts in different parallel planes, a practical implementation of the method will be obtained. Semiconductors are made from selenium, bismuth, antimony or tellurium. The Peltier module houses a large number of thermocouples placed between aluminum nitride or aluminum oxide ceramic plates.

Factors influencing the efficiency of TEM

• Current strength.
• Number of thermocouples (up to several hundred).
• Types of semiconductors.
• Cooling rate.

Larger values ​​have not yet been achieved due to low efficiency (5-8%) and high cost. For a TEM to work successfully, it is necessary to ensure effective heat removal from the heated side. This creates difficulties in the practical implementation of the method. If the polarity is reversed, the cold and hot sides reverse each other.

Advantages and disadvantages of modules

The need for TEMs arose with the advent of electronic devices requiring miniature cooling systems. The advantages of the modules are as follows:

• compactness;
• no moving joints;
• the Peltier module has a reversible operating principle when changing polarity;
• simplicity of cascade connections for increased power.

The main disadvantage of the module is low efficiency. This manifests itself in high power consumption to achieve the required cooling effect. In addition, it has a high cost.

Application of TEM

The Peltier module is used primarily for cooling microcircuits and small parts. A start was made for cooling elements of military equipment:

• microcircuits;
• infrared detectors;
• laser elements;
• crystal oscillators.

The Peltier thermoelectric module gradually began to be used in household appliances: to create refrigerators, air conditioners, generators, and thermostats. Its main purpose is to cool small objects.

CPU cooling

The main components of computers are constantly being improved, which leads to an increase in heat generation. Together with them, cooling systems are being developed using innovative technologies and modern controls. The Peltier module has found application in this area primarily in cooling microcircuits and other radio components. Traditional coolers can no longer cope with forced overclocking modes of microprocessors. And increasing the frequency of processors makes it possible to increase their performance.

Increasing the fan speed results in significant noise. It is eliminated by using a Peltier module in a combined cooling system. In this way, leading companies quickly mastered the production of efficient cooling systems, which began to be in great demand.

Heat is usually removed from processors by coolers. The air flow can be sucked in from outside or come from inside the system unit. The main problem is that the air temperature is sometimes insufficient for heat removal. Therefore, TEMs began to be used to cool the air flow entering the system unit, thereby increasing the efficiency of heat transfer. Thus, the built-in air conditioner is an assistant to the traditional computer cooling system.

Aluminum radiators are attached to both sides of the module. From the cold plate side, cooling air is pumped into the processor. After it takes the heat, another fan blows it out through the module's hot plate heatsink.

A modern TEM is controlled by an electronic device with a temperature sensor, where the degree of cooling is proportional to the heating of the processor.

Activating processor cooling also creates some problems.

1. Simple Peltier cooling modules are designed for continuous operation. Lower power consumption also reduces heat dissipation, which can cause the chip to overcool and subsequently freeze the processor.
2. If the operation of the cooler and refrigerator are not properly coordinated, the latter may switch to heating mode instead of cooling. The additional heat source will cause the processor to overheat.

Thus, modern processors require advanced cooling technologies that control the operation of the modules themselves. Such changes in operating modes do not occur with video cards, which also require intensive cooling. Therefore, TEM is ideal for them.

Do-it-yourself car refrigerator

In the middle of the last century, the domestic industry tried to master the production of small-sized refrigerators based on the Peltier effect. Existing technologies of that time did not allow this to be done. Now the limiting factor is mainly the high price, but attempts continue, and success has already been achieved.

Widespread production of thermoelectric devices allows you to create a small refrigerator with your own hands, convenient for use in cars. Its basis is a “sandwich”, which is made as follows.

1. A layer of heat-conducting paste type KPT-8 is applied to the upper radiator and the Peltier module is glued to one side of the ceramic surface.
2. Similarly, another radiator is attached to it from the bottom side, intended for placement in the refrigerator chamber.
3. The entire device is tightly compressed and dried for 4-5 hours.
4. Coolers are installed on both radiators: the upper one will remove heat, and the lower one will equalize the temperature in the refrigerator chamber.

The refrigerator body is made with a heat-insulating gasket inside. It is important that it closes tightly. You can use a regular plastic tool box for this.

12V power is supplied from the vehicle system. It can also be made from a 220 V AC network, with a power supply. The simplest AC to DC conversion circuit is used. It contains a rectifier bridge and a ripple-smoothing capacitor. It is important that at the output they do not exceed 5% of the nominal value, otherwise the efficiency of the device is reduced. The module has two outputs made of colored wires. A “plus” is always connected to red, and a “minus” to black.

The power of the TEM must correspond to the volume of the box. The first 3 digits of the marking indicate the number of pairs of semiconductor microelements inside the module (49-127 or more). expressed by the last two digits of the marking (from 3 to 15 A). If the power is not enough, you need to glue another module onto the radiators.

Note! If the current exceeds the power of the element, it will heat up on both sides and quickly fail.

Peltier module: electrical energy generator

TEM can be used to generate electricity. To do this, it is necessary to create a temperature difference between the plates, and the thermocouples located between them will generate electric current.

For practical use, you need a TEM of at least 5 V. Then you can use it to charge your mobile phone. Due to the low efficiency of the Peltier module, a DC-DC boost converter will be required. To assemble the generator you will need:

• 2 Peltier modules TEC1-12705 with plate size 40x40 mm;
• converter EK-1674;
• aluminum plates 3 mm thick;
• water pan;
• heat resistant glue.

Two modules are placed between the plates with glue, and then the entire structure is fixed to the bottom of the pan. If you fill it with water and put it on fire, you get the required temperature difference, which produces an EMF of the order of 1.5 V. By connecting the modules to a boost converter, you can increase the voltage to 5 V, which is necessary to charge the phone battery.

The greater the temperature difference between the water and the lower heated plate, the more efficient the generator is. Therefore, we must try to reduce the heating of water in different ways: make it running, replace it with fresh water more often, etc. An effective way to increase the temperature difference is to cascade the modules, when they are layered one on top of the other. Increasing the overall dimensions of the device allows you to place more elements between the plates and thereby increase the overall power.

The generator's performance will be sufficient to charge small batteries, operate LED lamps or a radio. Note! To create thermal generators, you will need modules capable of operating at 300-400 0 C! The rest are only suitable for trial testing.

Unlike other means of alternative generation of electricity, they can work while driving if you create something like a catalytic heater.

Domestic Peltier modules

TEMs of their own production appeared on our market not so long ago. They are highly reliable and have good performance. The Peltier module, which is in wide demand, has dimensions of 40x40 mm. It is designed for a maximum current of 6 A and voltage up to 15 V.

A domestic Peltier module can be purchased for a low price. At 85 W, it creates a temperature difference of 60 0 C. Together with a cooler, it is able to protect a processor from overheating with a power dissipation of 40 W.

Characteristics of modules from leading companies

Foreign devices are presented on the market in greater variety. To protect processors from leading companies, a PAX56B Peltier module is used as a refrigerator, the price of which, complete with a fan, is $35.

With dimensions of 30x30 mm, it maintains the processor temperature no higher than 63 0 C with a power output of 25 W. For power supply, a voltage of 5 V is sufficient, and the current does not exceed 1.5 A.

The PA6EXB Peltier module is well suited for cooling the processor, providing normal temperature conditions with a dissipation power of 40 W. The area of ​​its module is 40x40 mm, and the current consumption is up to 8 A. In addition to its impressive dimensions - 60x60x52.5 mm (including the fan) - the device requires free space around it. Its price is $65.

When a Peltier module is used, its technical characteristics must match the needs of the cooled devices. It is unacceptable that their temperature is too low. This can lead to moisture condensation, which can be harmful to electronics.

Modules for the manufacture of generators, such as, are distinguished by higher power - 72 W and 108 W, respectively. They are distinguished by markings, which are always applied to the hot side. The maximum permissible temperature of the hot side is 150-160 0 C. The greater the temperature difference between the plates, the higher the output voltage. The device operates at a maximum temperature difference of 600 0 C.

You can buy a Peltier module inexpensively - about $10 or less per piece, if you look hard enough. Quite often, sellers significantly inflate their prices, but you can find them several times cheaper if you buy them on sale.

Conclusion

The Peltier effect has now found application in the creation of small refrigerators necessary for modern technology. The reversibility of the process makes it possible to produce micropower stations that are in demand for charging batteries of electronic devices.

Unlike other means of alternative power generation, they can operate while driving if a catalytic heater is installed.

Greetings, banggood reader, astrologers have announced Peltier Week, so this review will talk about one interesting application of this thing. You are welcome under CUT.

Let's start with an educational program

As Wikipedia says, “A Peltier element is a thermoelectric converter, the operating principle of which is based on the Peltier effect - the occurrence of a temperature difference when an electric current flows.” I’m sure that after this phrase it didn’t become any clearer).

Ok let's try differently. Imagine a specific aquarium consisting of two types of zones. In the first zone of the aquarium, the fish swim quickly, in the second, slowly. Let’s also imagine blades spinning in water at the boundaries of the zones. The rules are as follows: 1) the fish swims to another zone only when its speed matches the speed set for the zone. 2) when crossing the boundaries of the zone, the fish can interact with the blades to increase or decrease its speed. Now let’s imagine several zones located sequentially. (zones with a higher speed will be called Z+ with low Z-) The fish is in Z+, it wants to move to Z-, it interacts with the blade at the border and begins to swim slower, while the blades (at the boundary Z+/Z-) begin to spin faster. Next, the fish wants to move to the next zone Z+, it needs to accelerate; it interacts with the blade at the boundary Z-/Z+ and accelerates; at the same time, the blade begins to spin more slowly. Then everything repeats itself. You may notice that some blades will slow down and others will speed up. The Peltier element works on a similar principle. Instead of fish there are electrons, instead of the speed of fish, the energy of electrons in semiconductors. When current flows through the contact of 2 semiconductors, the electron must acquire energy in order to move to a higher energy zone of another semiconductor. When this energy is absorbed, the contact point between the semiconductors cools. When current flows in the opposite direction, the contact point of the semiconductors heats up,
Moreover, the greater the current, the higher the effect of energy transfer; energy is transferred (and not magically lost) from the “cold” side to the “hot” side, therefore the Peltier element is capable of cooling objects to temperatures below room temperature (in other words, it is a semiconductor heat pump). If your task is simply to remove heat from the processor, transistor, etc. The use of a Peltier element is unprofitable because You will need a radiator capable of transferring heat from the cooled object + heat generated during operation of the Peltier element to the environment. I think the theory is over and we can move on.
Let's see what 13.90 greens looks like according to the sponsor of the review.

The module is a kind of 5-level sandwich; it consists of a pair of radiators and fans and the Peltier element itself.
The larger fan is designed to dissipate heat. If you apply force, it can be removed without unscrewing the screws.
The fan is the most ordinary (Power supply 12V size 90mm) covered with a grille, initially the fan is installed for air exhaust.

On the opposite side there is a small fan (Power supply 12V size 40mm)
The baby is screwed on conscience
Let's look at the radiators
Large radiator size 100mm*120mm height 20mm
Small radiator 40mm*40mm height 20mm. The radiators are fastened with two screws; the small radiator has a thread. When removing the radiator, thermal paste was found, which is good, but you can see that there is underpressure.
The contact with a large radiator is also not ideal.
The main conclusion is that if you want to get the most out of this module, be sure to look under the radiators. And if you erase the thermal paste, you can see that the element is installed here TEC1-12705(size 40mm*40mm*4mm) although the more powerful TEC1-12706 is declared. Manual for TEC1-12705

Let's remove the small radiator and try to start the module by measuring the temperatures of the “warm” and “cold” sides.
The temperature of the “cold” side is -16.1, “hot” 37.5 delta 53.6. current consumption at 12V was 4.2A.
The Peltier element entered the mode after 90s.

Now comes the fun part.
We find a metal and shiny plate and make a hole in it for the thermocouple.
Place thermal paste and install thermocouple
Next, we make a narrowly directed photodetector and a photodiode from black paper and ordinary components

We assemble the finished device, remembering the rule “the angle of incidence is equal to the angle of reflection”
Who guessed what it was? This is a device (well, more precisely, a model to demonstrate the principle of operation) for determining the dew point temperature/relative humidity. It works as follows: an IR LED shines into a reflective plate, after reflection, the light from the IR LED hits the IR photodiode. A voltage signal is collected from the reverse-biased IR photodiode. When the plate is cooled to the dew point temperature, condensation begins to collect on it, the intensity of the reflected radiation drops, and the signal on the photodiode changes. By recording the temperature of the plate and the surrounding air, the relative humidity can be found. For work I used Brymen BM869 (with homemade cable and software) and Uni-t UT61E
Below is the result
Red graph is plate temperature, blue graph is signal from the photodiode. We will consider the moment when the voltage from the photodiode has changed by half of the total voltage change to be the moment of condensation. Based on the set conditions, the measured dew point temperature in the room was +9C. The ambient air temperature was 26.7 (it was not displayed on the graphs because it was unchanged). At the same time, I launched the HTU21 module and observed the readings in the terminal. (a screenshot of the terminal has been added to graphics). Next, I used an online calculator to convert humidity to dew point temperature
The result of converting humidity from HTU21 to dew point temperature coincided with the directly measured dew point temperature. This means that if you determine the dew point using the method described above, and then do a recalculation, you can determine the humidity quite accurately (Well, of course, if you do everything like an adult). This method is called the chilled mirror method, and hygrometers built on this principle are called condensation hygrometers. I hope you enjoyed the review and learned something new. Thank you all for your attention.

The product was provided for writing a review by the store. The review was published in accordance with clause 18 of the Site Rules.

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