Semiconducting coolers Pelte
(Continuation)

Features of maintenance

Пельтье units applied as a part of resources of cooling of electronic units, differ rather high dependability, and unlike the refrigerators created on traditional processing technique, have no moving parts. And, as it was marked above, for increase in efficiency of the operation they admit cascade usage that allow to finish temperature of tanks of protected electronic units to negative values even at their considerable dissipation power.

However except obvious advantages, Пельтье units possesses also a number of specific properties and characteristics which is necessary for considering at their usage as a part of cooling resources. Some of them have been already marked, but for correct application of Пельтье units demand more detailed consideration. Following features of maintenance concern the major characteristics:

• Пельтье units selecting in the course of the operation a considerable quantity of heat, demand presence as a part of a cooler of appropriate heat sinks and the fans capable effectively to take away redundant heat from cooling units. It is necessary to mark, that thermoelectric units differ in rather low efficiency (efficiency) and, fulfilling functions of the thermal pump, they are powerful sources of heat. Usage of the given units as a part of resources of cooling of electronic accessories of the computer calls considerable growth of temperature in a system unit, that quite often demands additional measures and resources for lowering of temperature in computer tank. Otherwise the raised temperature in tank creates difficulties for operation not only for protected units and their systems of cooling, but also to other components of the computer. It is necessary to underline also, that Пельтье units are rather powerful additional load for a power supply unit. Taking into account value of a current of consumption of Пельтье units the value of power of a power supply unit of the computer should be not less than 250 W. All it leads to expediency of a choice of motherboards and tanks konstruktiva ATX with power supply units of sufficient power. Data usage konstruktiva facilitates the organisation of optimal thermal and electrical modes for accessories of the computer. It is necessary to mark, that there are coolers Pelte with an own power supply unit.
• Пельтье unit, in case of its output out of operation, isolates a cooled unit from the cooler heat sink. It leads to very fast violation of a thermal mode of a protected unit and its fast output out of operation from the subsequent overheat.
• The low temperatures arising in the course of operation of coolers Pelte of redundant power, promote condensation of a moisture from air. It represents danger to electronic parts as the condensate can call short circuits between units. For an exception of the given danger it is expedient to use coolers Pelte of optimal power. There will be a condensation or not, depends on several parametres. The major are: an ambient temperature (in this case temperature of air in tank), temperature of the cooled object and humidity of air. Than more warmly air in tank and the more humidity, the will occur condensation of a moisture and the subsequent mortality of electronic units of the computer more possibly. The table illustrating dependence temperature of condensation of a moisture on the cooled object depending on humidity and an ambient temperature is more low presented. Using this table, it is possible to instal easily, whether there is a danger of condensation of a moisture or not. For example, if external temperature 25°C, and humidity of 65 % moisture condensation on the cooled object occurs at temperature of its surface more low 18°C.

Temperature of condensation of a moisture

Except the specified features, it is necessary to consider and a number of the specific circumstances linked to usage of thermoelectric Пельтье units as a part of coolers, high-powered central processor units of powerful computers applied to cooling.

The architecture of modern processors and some system programs provide change energopotreblenija depending on loading of processors. It allows to optimise them energopotreblenie. By the way, it is provided also by standards energosberezhenija, the supported some functions which have been built in a firmware of modern computers. In usual conditions optimisation of operation of the processor and it energopotreblenija well affects as a thermal mode of the processor, and the common temperature balance. However it is necessary to mark, that modes with periodic change energopotreblenija can badly be combined with resources of cooling of the processors using Пельтье units. It is linked by that existing coolers Pelte, as a rule, are calculated for continuous operation. In this connection, the elementary coolers Pelte which is not possessing control devices, it is not recommended to use together with cooling programs, such as, for example, CpuIdle, and also with operating systems of Windows NT/2000 or Linux.

In case of processor transition in a mode reduced energopotreblenija and accordingly heat releases probably considerable lowering of temperature of tank and a processor chip. Subcooling of a kernel of the processor can call in some cases the time termination of its working capacity, and as the result, proof lag of the computer. It is necessary to remind, that according to the documentation of the corporation of Intel the minimum temperature at which correct operation of serial processors of Pentium II is guaranteed and Pentium III, usually makes +5 °C though as practice shows, they perfectly work and at lower temperatures.

Some problems can arise and as a result operations of some intrinsic functions, for example, what exercise administration of fans of coolers. In particular, control modes energopotrebleniem the processor in some computer systems provide change of speed of rotation of cooling fans through the built in hardware of the motherboard. In usual conditions it considerably improves a thermal mode of the processor of the computer. However in case of usage of the elementary coolers Pelte reduction of speed of rotation can already lead to deterioration of a thermal mode with fatal result for the processor owing to its overheat working Пельтье unit which except performance of functions of the thermal pump, is a powerful source of additional heat.

It is necessary to mark, that, as well as in case of central processor units of computers, coolers Pelte can be good alternative to traditional resources of cooling of the video chip sets used as a part of modern high-powered videoadapters. Operation of such video chip sets is accompanied by a considerable heat release and usually is not subject to an abrupt change of modes of their functioning.

To eliminate problems with modes changed energopotreblenija, calling condensation of a moisture from air and possible subcooling, and in some cases even an overheat of protected units, such as processors of computers, it is necessary to refuse usage of similar modes and of some intrinsic functions. However as alternative it is possible to use the systems of cooling providing intellectual controls by coolers Pelte. Such resources can inspect not only operation of fans, but also to change functional modes of the thermoelectric units used as a part of active coolers.

There were messages on experiments on embedding of miniature Пельтье units directly in chips of processors for cooling of their most critical structures. Such solution promotes the best cooling at the expense of lowering of a thermal resistance and allows to raise an operating frequency and productivity of processors considerably.