Semiconductor Peltier refrigerators

The operation of modern high-performance electronic components that form the basis of computers is accompanied by significant heat generation, especially when operating them in forced overclocking modes. Effective work Such components require adequate cooling means to ensure the required temperature conditions for their operation. As a rule, such means of supporting optimal temperature conditions are coolers based on traditional radiators and fans.

The reliability and performance of such devices are continuously increasing due to improvements in their design, use latest technologies and the use of various sensors and control means in their composition. This makes it possible to integrate such tools into computer systems, providing diagnostics and control of their operation in order to achieve the greatest efficiency while ensuring optimal temperature conditions for the operation of computer elements, which increases reliability and extends the period of their trouble-free operation.

The parameters of traditional coolers are constantly improving, however, Lately Such specific means of cooling electronic elements as semiconductor Peltier refrigerators appeared on the computer market and soon became popular (although the word cooler is often used, the correct term in the case of Peltier elements is refrigerator).

Peltier refrigerators, containing special semiconductor thermoelectric modules, the operation of which is based on the Peltier effect, discovered back in 1834, are extremely promising cooling devices. Such tools have been successfully used for many years in various fields of science and technology.

In the sixties and seventies, the domestic industry made repeated attempts to produce household small-sized refrigerators, the operation of which was based on the Peltier effect. However, the imperfection of existing technologies, low efficiency values ​​and high prices did not allow similar devices leave research laboratories and test benches.

But the Peltier effect and thermoelectric modules are not the preserve of scientists alone. In the process of improving technology, many negative phenomena have been significantly mitigated. These efforts have resulted in highly efficient and reliable semiconductor modules.

IN last years These modules, whose operation is based on the Peltier effect, began to be actively used for cooling a variety of electronic components of computers. In particular, they began to be used to cool modern powerful processors, the operation of which is accompanied by high level heat generation.

Thanks to its unique thermal and operational properties devices created on the basis of thermoelectric modules—Peltier modules—make it possible to achieve the required level of cooling of computer elements without any special technical difficulties or financial costs. As coolers for electronic components, these means of maintaining the required temperature conditions for their operation are extremely promising. They are compact, convenient, reliable and have very high operating efficiency.

Particularly great interest semiconductor refrigerators are presented as means that provide intensive cooling in computer systems, the elements of which are installed and operated in severe forced modes. The use of such overclocking modes often provides a significant increase in the performance of the electronic components used, and, consequently, as a rule, the entire computer system. However, the operation of computer components in such modes is characterized by significant heat generation and is often at the limit of the capabilities of computer architectures, as well as existing and used microelectronic technologies. Such computer components, the operation of which is accompanied by high heat generation, are not only high-performance processors, but also elements of modern high-performance video adapters, and in some cases, memory module chips. Similar powerful elements For their correct operation, they require intensive cooling even in standard modes and even more so in overclocking modes.

Peltier modules

Peltier refrigerators use a conventional, so-called thermoelectric refrigerator, the operation of which is based on the Peltier effect. This effect is named after the French watchmaker Peltier (1785-1845), who made his discovery more than a century and a half ago - in 1834.

Peltier himself did not quite understand the essence of the phenomenon he discovered. The true meaning of the phenomenon was established a few years later in 1838 by Lenz (1804-1865).

Lenz placed a drop of water in the recess at the junction of two rods of bismuth and antimony. When skipping electric current in one direction a drop of water froze. When current was passed in the opposite direction, the resulting ice melted. Thus, it was established that when an electric current passes through the contact of two conductors, depending on the direction of the latter, in addition to Joule heat, additional heat is released or absorbed, which is called Peltier heat. This phenomenon is called the Peltier phenomenon (Peltier effect). Thus, it is the inverse of the Seebeck phenomenon.

If in a closed circuit consisting of several metals or semiconductors, the temperatures at the contact points of the metals or semiconductors are different, then an electric current appears in the circuit. This phenomenon of thermoelectric current was discovered in 1821 by the German physicist Seebeck (1770-1831).

Unlike the Joule-Lenz heat, which is proportional to the square of the current strength (Q=R·I·I·t), the Peltier heat is proportional to the first power of the current strength and changes sign when the direction of the latter changes. Peltier heat, as shown by experimental studies, can be expressed by the formula:

Qп = П ·q

where q is the amount of electricity passed (q=I·t), P is the so-called Peltier coefficient, the value of which depends on the nature of the contacting materials and their temperature.

Peltier heat Qп is considered positive if it is released, and negative if it is absorbed.

Rice. 1. Scheme of the experiment for measuring Peltier heat, Cu - copper, Bi - bismuth.

In the presented diagram of the experiment of measuring Peltier heat, with the same resistance of the wires R (Cu+Bi) lowered into the calorimeters, the same Joule heat will be released in each calorimeter, namely according to Q=R·I·I·t. Peltier heat, on the contrary, will be positive in one calorimeter and negative in the other. In accordance with this scheme, it is possible to measure Peltier heat and calculate the values ​​of the Peltier coefficients for different pairs of conductors.

It should be noted that the Peltier coefficient is significantly dependent on temperature. Some values ​​of the Peltier coefficient for various pairs of metals are presented in the table.

Peltier coefficient values ​​for various pairs of metals
Iron-constantan		Copper-nickel		Lead-constantan
T, K	P, mV	T, K	P, mV	T, K	P, mV
273	13,0	292	8,0	293	8,7
299	15,0	328	9,0	383	11,8
403	19,0	478	10,3	508	16,0
513	26,0	563	8,6	578	18,7
593	34,0	613	8,0	633	20,6
833	52,0	718	10,0	713	23,4

Peltier coefficient, which is important technical characteristics materials, as a rule, are not measured, but are calculated through the Thomson coefficient:

P = a T

where P is the Peltier coefficient, a is the Thomson coefficient, T is the absolute temperature.

The discovery of the Peltier effect had a great influence on the subsequent development of physics, and subsequently various fields of technology.

So, the essence of the open effect is as follows: when an electric current passes through the contact of two conductors made of various materials, depending on its direction, in addition to Joule heat, additional heat is released or absorbed, which is called Peltier heat. The degree of manifestation of this effect largely depends on the materials of the selected conductors and the electrical modes used.

The classical theory explains the Peltier phenomenon by the fact that electrons transferred by current from one metal to another are accelerated or slowed down by the internal contact potential difference between the metals. In the first case, the kinetic energy of the electrons increases and is then released as heat. In the second case, the kinetic energy of the electrons decreases, and this loss of energy is replenished due to thermal vibrations of the atoms of the second conductor. As a result, cooling occurs. A more complete theory takes into account not the change in potential energy when an electron is transferred from one metal to another, but the change in total energy.

The Peltier effect is most strongly observed when p- and n-type semiconductors are used. Depending on the direction of electric current through the semiconductor contact different types- p-n- and n-p-junctions due to the interaction of charges represented by electrons (n) and holes (p), and their recombination, energy is either absorbed or released. As a result of these interactions and the energy processes generated, heat is either absorbed or released. The use of p- and n-type semiconductors in thermoelectric refrigerators is illustrated in Fig. 2.

Rice. 2. Use of p- and n-type semiconductors in thermoelectric refrigerators.

Combining a large number of pairs of p- and n-type semiconductors makes it possible to create cooling elements—Peltier modules—relatively high power. The structure of a semiconductor thermoelectric Peltier module is shown in Fig. 3.

Rice. 3. Structure of the Peltier module

The Peltier module is a thermoelectric refrigerator consisting of p- and n-type semiconductors connected in series, forming p-n- and n-p junctions. Each of these junctions has thermal contact with one of the two radiators. As a result of the passage of an electric current of a certain polarity, a temperature difference is formed between the radiators of the Peltier module: one radiator works like a refrigerator, the other radiator heats up and serves to remove heat. In Fig. Figure 4 shows the appearance of a typical Peltier module.

Rice. 4. Appearance Peltier module

A typical module provides a significant temperature difference of several tens of degrees. With appropriate forced cooling of the heating radiator, the second radiator - refrigerator, allows you to achieve negative values temperatures To increase the temperature difference, it is possible to cascade switch on Peltier thermoelectric modules while ensuring adequate cooling. This allows comparatively by simple means obtain a significant temperature difference and ensure effective cooling of the protected elements. In Fig. Figure 5 shows an example of cascade connection of standard Peltier modules.

Rice. 5. Example of cascade connection of Peltier modules

Cooling devices based on Peltier modules are often called active Peltier refrigerators or simply Peltier coolers.

The use of Peltier modules in active coolers makes them significantly more efficient compared to standard types coolers based on traditional radiators and fans. However, in the process of designing and using coolers with Peltier modules, it is necessary to take into account a number of specific features, arising from the design of the modules, their operating principle, the architecture of modern computer hardware and the functionality of system and application software.

The power of the Peltier module is of great importance, which, as a rule, depends on its size. Module low power does not provide the required level of cooling, which can lead to malfunction of the protected electronic element, for example, a processor due to its overheating. However, the use of modules with too much power can cause the temperature of the cooling radiator to drop to the level of moisture condensation from the air, which is dangerous for electronic circuits. This is because water continuously produced through condensation can cause short circuits in the computer's electronic circuits. It is appropriate to recall here that the distance between current-carrying conductors on modern printed circuit boards often amounts to fractions of millimeters. Nevertheless, in spite of everything, it was the powerful Peltier modules as part of high-performance coolers and the corresponding additional cooling and ventilation systems that allowed KryoTech and AMD, in joint research, to overclock AMD processors created using traditional technology to frequencies exceeding 1 GHz , that is, increase their frequency of operation by almost 2 times compared to their normal mode of operation. And it must be emphasized that this level of performance was achieved while ensuring the necessary stability and reliability of processor operation in forced modes. Well, the result of such extreme overclocking was a performance record among processors with the 80x86 architecture and instruction system. And the company KryoTech has made good money by offering its cooling units on the market. Equipped with appropriate electronic stuffing, they have proven to be in demand as platforms for high-performance servers and workstations. And AMD received confirmation of the high level of its products and rich experimental material for further improving the architecture of its processors. By the way, similar studies were carried out with Intel processors Celeron, Pentium II, Pentium III, as a result of which a significant increase in performance was also obtained.

It should be noted that Peltier modules during their operation distinguish relatively a large number of heat. For this reason, you should use not only a powerful fan as part of the cooler, but also measures to reduce the temperature inside the computer case to prevent overheating of other computer components. To do this, it is advisable to use additional fans in the computer case to ensure better heat exchange with the environment outside the case.

In Fig. Figure 6 shows the appearance of an active cooler, which uses a Peltier semiconductor module.

Rice. 6. Appearance of a cooler with a Peltier module

It should be noted that cooling systems based on Peltier modules are used not only in electronic systems such as computers. Such modules are used to cool various high-precision devices. Peltier modules are of great importance for science. First of all, this applies to experimental research carried out in physics, chemistry, and biology.

Information about Peltier modules and refrigerators, as well as the features and results of their use, can be found on Internet sites, for example, at the following addresses:

Features of operation

Peltier modules, used as components for cooling electronic components, are characterized by relatively high reliability, and, unlike refrigerators created using traditional technology, they have no moving parts. And, as noted above, to increase the efficiency of their operation, they allow cascade use, which makes it possible to bring the temperature of the housings of the protected electronic elements to negative values, even with their significant dissipation power.

However, in addition to the obvious advantages, Peltier modules also have a number of specific properties and characteristics that must be taken into account when using them as part of coolants. Some of them have already been noted, but for the correct application of Peltier modules they require more detailed consideration. The most important characteristics include the following operating features:

• Peltier modules, which generate a large amount of heat during their operation, require the presence of appropriate radiators and fans in the cooler that can effectively remove excess heat from the cooling modules. It should be noted that thermoelectric modules are characterized by a relatively low coefficient of performance (efficiency) and, while performing the functions heat pump, they themselves are powerful sources of heat. The use of these modules as part of cooling means for computer electronic components causes a significant increase in temperature inside the system unit, which often requires additional measures and means to reduce the temperature inside the computer case. Otherwise, the increased temperature inside the case creates operational difficulties not only for the protected elements and their cooling systems, but also for the rest of the computer components. It should also be emphasized that Peltier modules are a relatively powerful additional load for the power supply. Taking into account the current consumption of Peltier modules, the power of the computer power supply must be at least 250 W. All this leads to the advisability of choosing ATX motherboards and cases with power supplies of sufficient power. The use of this design makes it easier for computer components to organize optimal thermal and electrical conditions. It should be noted that there are Peltier refrigerators with their own power supply.
• The Peltier module, in the event of its failure, isolates the cooled element from the cooler radiator. This leads to a very rapid disruption of the thermal regime of the protected element and its rapid failure from subsequent overheating.
• Low temperatures that occur during the operation of Peltier refrigerators with excess power contribute to the condensation of moisture from the air. This poses a risk to electronic components as condensation can cause short circuits between components. To eliminate this danger, it is advisable to use Peltier refrigerators with optimal power. Whether condensation occurs or not depends on several parameters. The most important are: temperature environment(in this case, the air temperature inside the case), the temperature of the cooled object and air humidity. The warmer the air inside the case and the higher the humidity, the more likely moisture condensation will occur and subsequent failure of the computer's electronic components. Below is a table illustrating the dependence of the temperature of moisture condensation on a cooled object depending on humidity and ambient temperature. Using this table, you can easily determine whether there is a risk of condensation or not. For example, if the external temperature is 25°C and the humidity is 65%, then moisture condensation on the cooled object occurs when its surface temperature is below 18°C.

Moisture condensation temperature

Humidity, %
Temperature ambient, °C	30	35	40	45	50	55	60	65	70
30	11	13	15	17	18	20	21	23	24
29	10	12	14	16	18	19	20	22	23
28	9	11	13	15	17	18	20	21	22
27	8	10	12	14	16	17	19	20	21
26	7	9	11	13	15	16	18	19	20
25	6	9	11	12	14	15	17	18	19
24	5	8	10	11	13	14	16	17	18
23	5	7	9	10	12	14	15	16	17
22	4	6	8	10	11	13	14	15	16
21	3	5	7	9	10	12	13	14	15
20	2	4	6	8	9	11	12	13	14

In addition to these features, it is necessary to take into account a number of specific circumstances associated with the use of Peltier thermoelectric modules as part of coolers used to cool high-performance central processors of powerful computers.

The architecture of modern processors and some system programs provide for changes in power consumption depending on the load on the processors. This allows you to optimize their energy consumption. By the way, this is also provided for by energy saving standards, supported by some functions built into the hardware and software of modern computers. Under normal conditions, optimizing the operation of the processor and its power consumption has a beneficial effect on both the thermal regime of the processor itself and the overall thermal balance. However, it should be noted that modes with periodic changes in power consumption may not be compatible with cooling means for processors using Peltier modules. This is due to the fact that existing Peltier refrigerators are generally designed for continuous operation. In this regard, the simplest Peltier refrigerators that do not have control means are not recommended for use in conjunction with cooling programs, such as, for example, CpuIdle, as well as with Windows NT/2000 or Linux operating systems.

If the processor switches to a mode of reduced power consumption and, accordingly, heat dissipation, a significant decrease in the temperature of the processor case and crystal is possible. Overcooling of the processor core can cause, in some cases, a temporary cessation of its operation, and as a result, a permanent freeze of the computer. It is necessary to recall that in accordance with the documentation from Intel minimum temperature, which guarantees correct operation of serial Pentium II and Pentium III processors, is usually +5 °C, although, as practice shows, they work perfectly well at lower temperatures.

Some problems may also arise as a result of the operation of a number of built-in functions, for example, those that control cooler fans. In particular, processor power management modes in some computer systems involve changing the speed of cooling fans through the motherboard's built-in hardware. Under normal conditions, this significantly improves the thermal performance of the computer processor. However, in the case of using the simplest Peltier refrigerators, a decrease in the rotation speed can lead to a deterioration in the thermal regime with a fatal result for the processor due to its overheating by the operating Peltier module, which, in addition to performing the functions of a heat pump, is a powerful source of additional heat.

It should be noted that, as in the case of computer central processors, Peltier refrigerators can be a good alternative to traditional means of cooling video chipsets used in modern high-performance video adapters. The operation of such video chipsets is accompanied by significant heat generation and is usually not subject to sudden changes in their operating modes.

In order to eliminate problems with variable power consumption modes that cause moisture condensation from the air and possible hypothermia, and in some cases even overheating of protected elements such as computer processors, you should avoid using such modes and a number of built-in functions. However, as an alternative, cooling systems that provide intelligent controls for Peltier refrigerators can be used. Such tools can control not only the operation of fans, but also change the operating modes of the thermoelectric modules themselves used as part of active coolers.

There have been reports of experiments on embedding miniature Peltier modules directly into processor chips to cool their most critical structures. This solution promotes better cooling by reducing thermal resistance and can significantly increase the operating frequency and performance of processors.

Work towards improving systems for ensuring optimal temperature conditions for electronic elements is being carried out by many research laboratories. And cooling systems using Peltier thermoelectric modules are considered extremely promising.

Examples of Peltier refrigerators

Relatively recently, domestically produced Peltier modules appeared on the computer market. These are simple, reliable and relatively cheap ($7-$15) devices. Typically, a cooling fan is not included. Nevertheless, such modules allow you not only to get acquainted with promising cooling means, but also to use them for their intended purpose in protection systems for computer components. Here are brief parameters of one of the samples.

Module size (Fig. 7) - 40x40 mm, maximum current - 6 A, maximum voltage - 15 V, power consumption - up to 85 W, temperature difference - more than 60 °C. When providing powerful fan The module is capable of protecting the processor with power dissipation of up to 40 W.

Rice. 7. Appearance of refrigerator PAP2X3B

There are both less and more powerful versions of domestic Peltier modules on the market.

The range of foreign devices is much wider. Below are examples of refrigerators in the design of which Peltier thermoelectric modules are used.

Active Peltier refrigerators from Computernerd

Name	Manufacturer / supplier	Fan parameters	CPU
PAX56B	computernerd	ball-bearing	Pentium/MMX up to 200 MHz, 25 W
PA6EXB	computernerd	dual ball-bearing, tachometer	Pentium MMX up to 40 W
DT-P54A	DesTech Solutions	dual ball bearing	Pentium
AC-P2	AOC Cooler	ball bearing	Pentium II
PAP2X3B	computernerd	3 ball bearing	Pentium II
STEP-UP-53X2	Step Thermodynamics	2 ball bearing	Pentium II, Celeron
PAP2CX3B-10 BCool PC-Peltier	computernerd	3 ball-bearing, tachometer	Pentium II, Celeron
PAP2CX3B-25 BCool-ER PC-Peltier	computernerd	3 ball-bearing, tachometer	Pentium II, Celeron
PAP2CX3B-10S BCool-EST PC-Peltier	computernerd	3 ball-bearing, tachometer	Pentium II, Celeron

The PAX56B refrigerator is designed to cool Pentium and Pentium-MMX processors from Intel, Cyrix and AMD operating at frequencies up to 200 MHz. A thermoelectric module measuring 30x30 mm allows the refrigerator to maintain a processor temperature below 63 °C with a power dissipation of 25 W and an external temperature of 25 °C. Due to the fact that most processors dissipate less power, this cooler allows you to keep the processor temperature much lower than many alternative coolers based on radiators and fans. The PAX56B refrigerator's Peltier module is powered by a 5V source capable of delivering 1.5A maximum. The fan of this refrigerator requires a voltage of 12 V and a current of 0.1 A (maximum). PAX56B refrigerator fan parameters: ball-bearing, 47.5 mm, 65000 hours, 26 dB. The overall size of this refrigerator is 25x25x28.7 mm. The estimated price of the PAX56B refrigerator is $35. The indicated price is given in accordance with the company’s price list for mid-2000.

The PA6EXB refrigerator is designed to cool more powerful Pentium-MMX processors that dissipate power up to 40 W. This refrigerator is suitable for all processors from Intel, Cyrix and AMD, connected via Socket 5 or Socket 7. The Peltier thermoelectric module included in the PA6EXB refrigerator has a size of 40x40 mm and consumes a maximum current of 8 A (usually 3 A) at a voltage of 5 B with connection via a standard computer power connector. The overall size of the PA6EXB refrigerator is 60x60x52.5mm. When installing this refrigerator, for good heat exchange between the radiator and the environment, it is necessary to provide an open space around the refrigerator of at least 10 mm at the top and 2.5 mm at the sides. The PA6EXB refrigerator provides a processor temperature of 62.7 °C with a power dissipation of 40 W and an external temperature of 45 °C. Considering the operating principle of the thermoelectric module included in this refrigerator, in order to avoid moisture condensation and short circuits, it is necessary to avoid using programs that put the processor into sleep mode long time. The approximate price of such a refrigerator is $65. The indicated price is given in accordance with the company’s price list for mid-2000.

The DT-P54A refrigerator (also known as Computernerd's PA5B) is designed for Pentium processors. However, some companies offering these refrigerators in the market also recommend it to Cyrix/IBM 6x86 and AMD K6 users. The radiator included in the refrigerator is quite small. Its dimensions are 29x29 mm. The refrigerator has a built-in temperature sensor that will notify you of overheating if necessary. It also controls the Peltier element. The kit includes an external monitoring device. It performs the functions of monitoring the voltage and the operation of the Peltier element itself, the operation of the fan, as well as the temperature of the processor. The device will generate an alarm if the Peltier element or fan fails, if the fan is spinning at less than 70% of the required speed (4500 RPM), or if the processor temperature rises above 145°F (63°C). If the processor temperature rises above 100°F (38°C), the Peltier element is automatically turned on, otherwise it is in shutdown mode. The latter function eliminates problems associated with moisture condensation. Unfortunately, the element itself is glued to the radiator so tightly that it is impossible to separate it without destroying its structure. This makes it impossible to install it on another, more powerful radiator. As for the fan, its design is characterized by a high level of reliability and it has high parameters: supply voltage - 12 V, rotation speed - 4500 RPM, air supply speed - 6.0 CFM, power consumption - 1 W, noise characteristics - 30 dB. This refrigerator is quite efficient and useful for overclocking. However, in some cases of overclocking a processor, you should simply use a large radiator and a good cooler. This refrigerator is priced between $39 and $49. The indicated price is given in accordance with the price list of several companies as of mid-2000.

The AC-P2 refrigerator is designed for Pentium II processors. The kit includes a 60 mm cooler, a radiator and a 40 mm Peltier element. It is not suitable for Pentium II processors 400 MHz and higher, since SRAM memory chips are practically not cooled. The estimated price for mid-2000 is $59.

Refrigerator PAP2X3B (Fig. 8) is similar to AOC AC-P2. Two 60 mm coolers are added to it. Problems with cooling SRAM memory remain unresolved. It is worth noting that the refrigerator is not recommended to be used in conjunction with cooling programs, such as, for example, CpuIdle, as well as under Windows NT or Linux operating systems, since moisture condensation on the processor is likely. The estimated price for mid-2000 is $79.

Rice. 8. Appearance of refrigerator PAP2X3B

The STEP-UP-53X2 refrigerator is equipped with two fans that pump a large amount of air through the radiator. Estimated price for mid-2000: $79 (Pentium II), $69 (Celeron).

Bcool series refrigerators from Computernerd (PAP2CX3B-10 BCool PC-Peltier, PAP2CX3B-25 BCool-ER PC-Peltier, PAP2CX3B-10S, BCool-EST PC-Peltier) are designed for Pentium II and Celeron processors and have similar characteristics that are presented in following table.

BCool series refrigerators

Item		PAP2CX3B-10 BCool PC-Peltier	PAP2CX3B-25 BCool-ER PC-Peltier							PAP2CX3B-10S BCool-EST PC-Peltier
Recommended processors		Pentium II and Celeron
Number of fans		3
Central fan type		Ball-Bearing, tachometer (12 V, 120 mA)
Center Fan Size		60x60x10 mm
External fan type		Ball Bearing	Ball-bearing, tachometer							Ball-bearing, thermister
External Fan Size		60x60x10 mm	60x60x25 mm
Voltage, current		12 V, 90 mA	12 V, 130 mA							12 V, 80-225 mA
Total fan coverage area		84.9 cm 2
Total current for fans (power)		300 mA (3.6 W)	380 mA (4.56 W)							280-570 mA (3.36-6.84 W)
Number of pins on the heatsink (center)		63 long and 72 short
Number of pins on the heatsink (each edge)		45 long and 18 short
Total number of pins on the heatsink		153 long and 108 short
Radiator dimensions (center)		57x59x27 mm (including thermoelectric module)
Radiator dimensions (each edge)		41x59x32 mm
General radiator dimensions		145x59x38 mm (including thermoelectric module)
General dimensions of the refrigerator		145x60x50 mm	145x60x65 mm
Refrigerator weight		357 grams	416 grams							422 grams
Guarantee		5 years
Estimated price (2000)		$74.95	$79.95							$84.95

It should be noted that the BCool group of refrigerators will also include devices that have similar characteristics, but do not have Peltier elements. Such refrigerators are naturally cheaper, but also less effective as a means of cooling computer components.

When preparing this article, materials from the book “PC: Settings, Optimization and Overclocking” were used. 2nd ed., revised. and additional, - St. Petersburg: BHV - Petersburg. 2000. - 336 p.

During the struggle for environmental friendliness and a decent existence, attention is paid to the smallest details. If you are tired of the constant noise of the cooler in the processor - remember, the device requires cooling, otherwise the BIOS will simply turn off the system unit along with the operating system. And in the heat you want peace and quiet. The solution has been found. Previously they said that refrigerators do not rely exclusively on compressors; alternative models have been created. Let's think, perhaps we will be able to assemble the refrigerator with our own hands.

The history of refrigerators, or a manual for the inventor

We mentioned in reviews about adsorption refrigerators running on blue fuel. The gas, when burned, causes the refrigerant to circulate and cool the compartments. The undoubted advantage of the design is noiselessness. You can hear a slight hiss from the combustion of fuel and the flow of liquid through the tubes. But the solution is far from the only one. They wrote that expensive car refrigerators work on a different principle - on Peltier elements.

In 1834 it was established that when passing direct current Heat is released or absorbed through conductors and semiconductors. The effect was not attributed to the Joule-Lenz law: in the latter case, heat was released, but cooling remained unattainable. No one gave a scientific explanation, but it became known that when current is passed in one direction, heat is absorbed and released in the other!

There is a known case when a student reported to a teacher on the subject of digital technologies; computers have not yet acquired the power they have today. Pentium II processors have just appeared on the Russian market, although fourth ones have, of course, already been seen in the USA. It came down to powering the computer's brain, to the desire to constantly reduce the voltage.

We noticed that the processor consumes 75 W. At the same time, the supply voltage remained around 3 V. It turns out that the small crystal consumed current... 25 A. Any battery when charging is not capable of this. The teacher spoke out, but turned out to be not entirely right.

At this low voltage, the processor actually consumes a huge current, part of the power is spent on useful needs, and heat is inevitably released into the environment. And tangible! Without a cooler, the processor can reach the boiling point; it would heat up further, but the protection systems will turn off the power earlier. It turns out that the processor consumes significant power. Recently, Peltier elements have appeared on the market, designed to cool the raging brain. A certain user noticed that the processor cooled down... to minus 10 degrees Celsius. Impressive?

Peltier elements cannot be called cheap. How to build a homemade refrigerator based on them: place them parallel inside a thermally insulated container, where the temperature will gradually drop. But the freezing power of refrigerators is not measured in watts, it is calculated by the number (in kilograms) of products whose temperature can be reduced to a given temperature. We don’t know what is meant by the statement that the power of the Peltier element is 77 W. At a price of 300 rubles apiece, it’s worth trying to calculate the cost of a homemade refrigerator by correlating the specified parameters. We offer a different way.

Remember, in the reviews they presented a method for determining the required heating power of a room, and now we use it in the reverse order. Experiment steps:

1. You will need an ordinary thermometer. Better than a simple street one. We will place the thermometer in our homemade refrigerator.
2. We make the body. Real refrigerators use polyurethane foam for thermal insulation. Buy a can at the store building materials. Foam plastic will also work; we recommend using reflective insulation of the Penofol type or similar. For example, take a box, tightly trim it on both sides with the mentioned material, in fact, a good homemade refrigerator is already ready. For information, the material was taken from the space industry, where it was used to create spacesuits. The sun's rays are deadly outside the atmosphere, and the cosmic cold will make Sauron himself shudder, but all of the above did not cause any particular harm to the astronaut under a layer of Penofol. Of course, gold and silver were used in the spacesuits, and not aluminum; perhaps they did not use polyethylene. Fact - the characteristics of the material are amazing.
3. The cooler will initially be a single Peltier element. We mount it with adhesive sealant. Then we will show a technique that allows you to find the number of modules needed for a homemade refrigerator to start freezing.

Calculation method for a homemade refrigerator using Peltier elements

We proceed from the fact that heat loss depends linearly on the temperature difference inside and outside a homemade refrigerator. Let's go from simple to complex:

1. Let’s say the temperature in the room is 20 ºС and remains unchanged throughout the experiment. Let's start the research. Obviously, in the absence of Peltier elements, the temperature inside the refrigerator will be 20 ºС. This is the first point on the straight line (losses increase linearly from the temperature difference between the outside and inside of a homemade refrigerator). We will install a Peltier element with radiators on both sides, and the outer one will be blown by a cooler to enhance the effect.
2. After a while, the temperature in the 30-liter compartment was 14 ºС. We claim that by adding two more Peltier elements with radiators and coolers, anyone will receive 2 degrees of heat inside a homemade refrigerator if the room is 20 ºC warm. Scheme:

Conclusions on the design of a homemade refrigerator

Readers will draw the rest of their conclusions on their own: a homemade refrigerator will give 2 degrees of heat on the Celsius scale if you equip the device with three Peltier elements with coolers. It is permissible to generalize experience, select optimal insulation, and vary conditions. For example, remove coolers so as not to make noise and waste energy. This will simplify the design. But we want to cool the ardor of the inventors: in real, not homemade refrigerators, two fans are used, for the cold and hot circuits. Experiment.

The refrigerator device will withstand computer unit nutrition. Remember how much the processor consumes! The Peltier element is far from the most important thing inside. The voltage has already been adjusted in advance, so you don’t have to look for rare parts. You buy three Peltier elements to make your own refrigerator, take a power supply from an old PC, build a box with two coolers, and get the finished product. Moreover, it can operate from a car battery.

The principle of operation of the refrigerator is so obvious that children can understand it. When the direction of the current changes, the Peltier elements work to heat. It's good to have warm food nearby when there is no heating device around. In the latter case, the law works in reverse side. Three Peltier elements inside a homemade refrigerator will provide a temperature 18 ºС above the environment. If the car has 25, the box will show 43. Enough to have a snack and not complain. It turns out that there are two devices in one person.

We would like to thank the author of the YouTube video for the great idea on how to make a refrigerator yourself. Let the idea not be very successful, but only because the volume is large. Peltier processor elements are not so powerful that they can single-handedly overcome a large volume that is not fully formed.

Do-it-yourself car refrigerator using Pelte elements

While I was doing construction country house I couldn’t help but want to figure out how else I could use extruded polystyrene foam. Today this is one of the most effective insulation materials with a huge number of advantages and very affordable price. The first thing I realized was that for grocery shopping trips to the hypermarket it is very useful to have a thermos container in which you can safely transport frozen food.

To make such a box it took 160 rubles and half an hour of free time. But I decided to go further and modify the design in order to use it as a stand-alone refrigerator.

Let's start making!

So, let's start with a thermos container. We will need one sheet of polystyrene foam with dimensions 1200x600 mm, thickness 50 mm, a stationery knife and a tape measure. The cost of such a sheet in any hardware store- 160 rubles. We cut the sheet according to the template, take the polyurethane foam and glue together such a container.

Here is a diagram of cutting the sheet. The sheet has sides 20 mm thick; they need to be cut off on all sides except the bottom. The sheets are glued together polyurethane foam. The technology is simple. Apply a little foam to the gluing area, wait 1 minute, press the sheets tightly against each other and then manually control for 5 minutes so that they do not move due to the expansion of the foam. The main thing is not to leave it unattended. Only a small piece of polystyrene foam, marked gray on the diagram.

Pay attention to the design of the lid; I cut one of the large sheets from the diagram above into 3 parts in place when gluing it together to ensure a tight fit. After this, the outside of the box can be painted. The paint slightly corrodes the polystyrene foam, so it is better to paint in two stages. The resulting container weighs 820 grams and has incredible heat loss performance. You can put several kilograms of frozen food in such a box and transport it for several hours without any problems. The main thing is not to mix frozen and chilled foods. You can supplement the design with a cold accumulator.

Or you can modify the design to get a full-fledged refrigerator. For these purposes, we will use a Peltier element - a thermoelectric converter, the operating principle of which is based on the occurrence of a temperature difference when an electric current flows. These are the elements that are used in serial car refrigerators, as well as ventilated car seats.

Cost of one Pelte element maximum power 60 W on aliexpress - 130-150 rubles. Model TEC1-12706. During operation, one side of the element heats up, the other cools. To prevent the element from burning, it is necessary to intensively remove heat from the hot side. For this we need CPU cooler with a radiator from a computer store, costing 250 rubles. To improve air circulation inside refrigeration chamber To avoid freezing of the radiator, I decided to install fans on both sides. We will also need a thermostat with an external temperature sensor and a relay, costing 170 rubles, which will allow us to control the set temperature inside the container. Well, an extension cable with a connector for a car cigarette lighter for 100 rubles.

So, let's start assembling.

We install the Peltier element using thermal paste (included with the cooler) between two aluminum radiators. It is worth noting here that the temperature gradient of the installation can be increased by assembling 2 or 3 Peltier elements installed in series. Thus, so that one Peltier element cools the other. In this version, it is possible to get in the container negative temperature up to -18 degrees Celsius. We lay a piece of foam thermal insulation along the perimeter between the element.

We connect the radiators to each other with standard mounting plates to the motherboard, connecting them using plastic clamps. This also allows the cold and hot sides to be thermally isolated from each other. Test run of installation. The more intensely we cool the hot side, the lower the temperature on the cold side will be. Here the fans are aimed at supplying air to the radiators; this is less efficient than if they are turned over to blow them out. In the improvised box, we managed to achieve a temperature of -3 degrees, at an ambient temperature of +26. The photo clearly shows the model of the coolers; their advantage is the large area of ​​the radiator support area. And as a thermal insulation pad, I used a piece of thermal insulation for round pipes.

Now let's integrate the thermoelectric converter into the new container lid. For the convenience of placing the entire structure, we will increase the thickness of the cover to 100 mm (2 sheets of polystyrene foam). This photo clearly shows the perimeter gasket between the two radiators.

Artistic cutting for expanded polystyrene and processing sandpaper. Let's paint again. After painting, the outer shell of polystyrene foam becomes stronger.

We coat the seams with sealant, turn both fans over to blow out. Among the potential improvements, it might be worth reducing the fan speed on the cold side (currently both fans operate at maximum speed).

We install the thermostat board next to the case and fix the power wire in this simple way. First we press the plate using self-tapping screws, then fix it with sealant.

Container assembled. The weight of the container without a lid is 800 grams; the lid with the assembled thermoelectric converter weighs the same. The total costs are 1000 rubles and a couple of hours of time. Tests with chilled products in the trunk of a car showed the system’s ability to maintain the temperature at the bottom (!) of the container within +5 degrees Celsius, at an ambient temperature of +29 degrees (yes, it is much warmer in the trunk, even with the air conditioner running) and current consumption - 3 Ampere. I think this is an excellent result.

I plan to make the next container from 3 in series installed elements Peltier to get a full-fledged freezer.

A great craft for the summer is to make a miniature refrigerator with low-voltage power. A variety of supply voltages (220 V, 12 V, 5 V) makes it possible to use such a refrigerator almost anywhere: in the car, office, home, etc. This is a great thing to cool drinks on a hot summer day.

Will need

Manufacturing a miniature refrigerator using a Peltier element

The case was made of arbitrary dimensions, taking into account the placement of the cooling unit, power supply and beverage chamber. It will consist of two sections: one for the technical part, the other for cooling products.
We make the body. We mark a piece of hardboard using a pencil and ruler.

We cut out all the elements with a hacksaw.

All body parts are ready.

From the middle part dividing the refrigerator into two parts, we cut out a window for a radiator with a Peltier module.

We apply the cooling unit to the side of the case.

And we drill a lot of holes on both sides. That is, the air flow will enter from one side through the holes in the side. Pass through the radiator, picking up heat and exiting through the holes on the other side.

We paint spray paint from a spray can all the parts of the refrigerator body.

Let's start assembling.

Glue the separating part of the cooling block with hot glue.

We glue all parts of the body on both sides.

The cooling unit rests on a piece of wood that is glued to the base.

You will need two sections for lighting LED strip at 12 V. One color is white, the other is colored.

Screw on the small fan.

We divide the technical part of the refrigerator into two parts. The power source will be located at the top. The dividing wall is placed on square pieces of wooden slats glued to the sides.

Installing the back wall.

We will make the door from a piece acrylic glass. Mark with a ruler and pencil.

You can buy miniature loops or make your own. Glue them on with instant glue.

We cover the sides of the acrylic glass with black self-adhesive tape.

Glue the handle to the door.

We will organize lighting. Solder the contacts to the mini limit switch.

Solder the wires to the pieces of LED strip. We glue the pieces themselves onto a mini shelf made from the same acrylic.

We connect the backlight, fans, Peltier element.

Install the switch on the side.

We isolate all open twists.

Close the compartment with the cooling unit. This must be done to prevent hot air from rising and heating the power source.

Drill a hole for the 220 V power cable.

To prevent the refrigerator door from opening, we will install small neodymium magnets from a broken sidir on the side.

Closing top cover, but before that we cut in the power switch and solder the wires. Now the refrigerator can be turned off with the button on top.

Close the lid and secure with glue.

For proper thermal insulation we paste over inner part refrigerator with thin foam. We place the cut out foam panels on hot glue.

And finally, the result of the work is such that in thirty minutes the temperature inside the chamber dropped from 42 to 16 degrees Celsius. The drinks were cooled to a temperature of 20 degrees Celsius. And all this in 30 minutes!

Of course, the efficiency of such a refrigerator is much lower than that of a compressor, but it also has its advantages, one of which is low voltage supply, which can be not only 12 V but also 5 V! Naturally, it is quite possible to power it from a computer’s USB port, although the output will be lower than when powered by a voltage of 12 V.
The total power consumption when powered from a 220 V network is about 100 W.More detailed instructions for assembly in the video below.

While I was building a country house, I couldn’t help but think of another way to use extruded polystyrene foam. Today this is one of the most effective insulation materials with a huge number of advantages and a very affordable price. The first thing I realized was that for grocery shopping trips to the hypermarket it is very useful to have a thermos container in which you can safely transport frozen food. To make such a box it took 160 rubles and half an hour of free time. But I decided to go further and modify the design in order to use it as a stand-alone refrigerator.

Let's start making!

2. So, let's start with a thermos container. We will need one sheet of polystyrene foam with dimensions 1200x600 mm, thickness 50 mm, a stationery knife and a tape measure. The cost of such a sheet in any hardware store is 160 rubles. We cut the sheet according to the template, take the polyurethane foam and glue together such a container.

3. Here is a diagram for cutting the sheet. The sheet has sides 20 mm thick; they need to be cut off on all sides except the bottom. The sheets are glued together with polyurethane foam. The technology is simple. Apply a little foam to the gluing area, wait 1 minute, press the sheets tightly against each other and then manually control for 5 minutes so that they do not move due to the expansion of the foam. The main thing is not to leave it unattended. Only a small piece of polystyrene foam will be left over, marked in gray in the diagram.

4. Pay attention to the design of the lid; I cut one of the large sheets from the diagram above into 3 parts in place when gluing it together to ensure a tight fit. After this, the outside of the box can be painted. The paint slightly corrodes the polystyrene foam, so it is better to paint in two stages. The resulting container weighs 820 grams and has incredible heat loss performance. You can put several kilograms of frozen food in such a box and transport it for several hours without any problems. The main thing is not to mix frozen and chilled foods. You can supplement the design with a cold accumulator.

5. Or you can modify the design to get a full-fledged refrigerator. For these purposes, we will use a Peltier element - a thermoelectric converter, the operating principle of which is based on the occurrence of a temperature difference when an electric current flows. These are the elements that are used in serial car refrigerators, as well as ventilated car seats.

The cost of one Pelte element with a maximum power of 60 W on aliexpress is 130-150 rubles. Model TEC1-12706. During operation, one side of the element heats up, the other cools. To prevent the element from burning, it is necessary to intensively remove heat from the hot side. To do this, we need a processor cooler with a radiator from a computer store, costing 250 rubles. To improve air circulation inside the refrigerator compartment and prevent the radiator from freezing, I decided to install fans on both sides. We will also need a thermostat with an external temperature sensor and a relay, costing 170 rubles, which will allow us to control the set temperature inside the container. Well, an extension cable with a connector for a car cigarette lighter for 100 rubles.

So, let's start assembling.

6. We install the Peltier element using thermal paste (included with the cooler) between two aluminum radiators. It is worth noting here that the temperature gradient of the installation can be increased by assembling 2 or 3 Peltier elements installed in series. Thus, so that one Peltier element cools the other. In this option, it is possible to get a negative temperature of up to -18 degrees Celsius in the container. We lay a piece of foam thermal insulation along the perimeter between the element.

7. We connect the radiators to each other with standard mounting plates to the motherboard, connecting them using plastic clamps. This also allows the cold and hot sides to be thermally isolated from each other. Test run of installation. The more intensely we cool the hot side, the lower the temperature on the cold side will be. Here the fans are aimed at supplying air to the radiators; this is less efficient than if they are turned over to blow them out. In the improvised box, we managed to achieve a temperature of -3 degrees, at an ambient temperature of +26. The photo clearly shows the model of the coolers; their advantage is the large area of ​​the radiator support area. And as a thermal insulation pad, I used a piece of thermal insulation for round pipes.

8. Now let's integrate the thermoelectric converter into the new container lid. For the convenience of placing the entire structure, we will increase the thickness of the cover to 100 mm (2 sheets of polystyrene foam). This photo clearly shows the perimeter gasket between the two radiators.

9. Artistic cutting on polystyrene foam and sandpaper processing. Let's paint again. After painting, the outer shell of polystyrene foam becomes stronger.

10. Coat the seams with sealant, turn both fans over to blow out. Among the potential improvements, it might be worth reducing the fan speed on the cold side (currently both fans operate at maximum speed).

11. We install the thermostat board next to the case and fix the power wire in this simple way. First we press the plate using self-tapping screws, then fix it with sealant.

12. Container assembled. The weight of the container without a lid is 800 grams; the lid with the assembled thermoelectric converter weighs the same. Total expenses - 1000 rubles and a couple of hours of time. Tests with cooled products in the trunk of a car showed the system’s ability to maintain the temperature at the bottom (!) of the container within +5 degrees Celsius, at an ambient temperature of +29 degrees (yes, it is much warmer in the trunk, even with the air conditioner running) and current consumption - 3 Ampere. I think this is an excellent result.

I plan to make the next container from 3 Peltier elements installed in series to get a full-fledged freezer.