Tempco Blog articles

Thermal machines and the Four fingers rule

In addition to the Five fingers rule, referring to the five parameters required for the correct sizing of a heat exchanger, there is also a Four fingers rule, which is employed when designing a thermal machine.

A thermal machine that can be a dry cooler, or a refrigerating group, or a cooling tower. In this case, there are indeed four parameters required for the proper sizing of the machinery: the kind of fluid to be cooled and its flow rate; the inlet temperature, which is the temperature of the fluid as it comes from the process; the outlet temperature, which is the temperature of the fluid required when it goes back to the process; the design ambient air temperature.



Ambient air temperature that in case of a chiller is related to the condensation process, in case of a dry cooler is the temperature of the air that will cool the fluid. And finally, in case of an evaporative tower is the wet-bulb temperature, a key value for the evaporation process.

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Third line of carbon ceramic brakes furnaces cooling

We’re currently supplying the third line for the cooling of furnaces employed in the production of carbon ceramic brakes. The Tempco customer has eventually standardized both the PLC logic and the selection of all the components, with an optimization as well of the exchangers, pumps, tanks, levels and interfaces for the application.

The line is intended to cool the furnaces that provide the thermal treatment of the discs of carbon ceramic brakes. The Tempco solution ensures the cooling of the furnaces, because in case of an improper, or even absent cooling process, the whole brakes batch could go wasted. But also the furnaces themselves could be damaged, with obviously an even greater loss.

The treatment achieved within the furnaces is therefore a critical step in this kind of application, as well as the accuracy and reliability of the cooling system. In order to ensure always the maximum reliability, the cooling plant has been equipped with redundant security systems, using tower water that feeds a heat exchanger and pumps providing the circulation of the water within the furnaces. With water in a closed circuit among the tower, the exchanger and the furnaces. In case of power failure, an emergency generator starts automatically with a valves circuit automatically opening, allowing mains water to flow within the plant decreasing the temperature of the furnaces, saving both the machinery and the production.

Tempco raffreddamento forni produzione freni carboceramici


Finally, the customer is already planning a further expansion of the system with the addition of a fourth cooling line for the furnaces.

Tempco produzione freni carboceramici alte prestazioni raffreddamento

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Five fingers rule and heat exchangers

Have you ever heard about the Five fingers rule when sizing and designing a heat exchanger? There are in fact some important data that are required in order to properly design a heat exchanger.

These data are: the fluid to be heated or cooled and its flow rate; the inlet temperature of the fluid, which is the temperature of the fluid when it arrives from the process; the expected outlet temperature of the fluid, which is the temperature of the fluid required to get back into the process; the kind of working fluid and how much of cooling or heating fluid is available, expressed in flow rate (kg/hour, cubic meters/hour); the temperature of the working fluid available.

Five data, five fingers: having these five parameters we can calculate a thermal balance, finding out all of the required data to properly size the exchanger. Let’s clearly start taking for granted that we already know the kind of fluid employed, working for example with a water/water exchanger, or water/oil or steam/water.

Someone could object that also the pressure drop is needed. But let’s suppose we have a fluid at a certain defined pressure, that allows to define a certain pressure drop value. Usually this is a value provided by the customer, or anyway we can indicate the ideal pressure drops in order to ensure the best performances of the exchanger. Otherwise, the customer will ask to recalculate the pressure drops available based on the pump or the pressure of the available fluid.

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Energy recovery with immersion exchangers in industrial laundries

A recent application of energy recovery from waters employed in an industrial laundry, for a customer in Puglia, represents for Tempco a further demonstration of the actual flexibility and versatility of TCOIL immersion exchangers. In the past we’ve already developed an application thanks to the free shape design offered by these kind of dimple jacket heat exchangers, employed on mangano ironers in industrial automatic ironing.

This new application of TCOIL immersion exchangers in industrial laundries is the first of its kind that we supply, and this is in fact a very brilliant and innovative solution, giving the customer a huge advantage in terms of energy saving. The customer has indeed water available at the temperature of 45-50° C, that is conveyed into the exchanger, with feeding water at 12° C that can therefore be heated at 35-40° C. The gain is about 20-25° C, and the water heated thanks to the recovered thermal energy is further heated in a boiler at 45° C ready for a new working cycle. A power saving of about 2/3 of the required power is thus obtained, so that for example the customer has a consumption of only 300 kW instead of 1.000 kW.

Tempco scambiatori TCOIL a immersione lavanderie industriali

This is a very smart application, with heat recovery and a strong energy saving, that becomes even more interesting these days due to the huge increase in gas and energy costs. The increase of energy prices is indeed reducing the payback of a similar solution, drastically shortening the return of investment for the customers, because if once it would have been calculated in 10 years, now it potentially decreases to only 3 years. With then a ROI very much more accessible, even because this kind of solution, with stainless steel construction, offers a very much longer working life.

Once again, another example of the change of paradigm similar to the switch from gas to electrical heating, that we were speaking about in our video on the electrification of heating in thermoregulating units.

Tempco scambiatori TCOIL lavanderie industriali

Tempco scambiatori a immersione TCOIL lavanderie industriali

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Pressure drop and thermal transfer performances in exchangers, why do they increase together?

There is a little trick that I’m explaining here related to the functioning and thermal transfer efficiency of heat exchangers: why the performances increase while the pressure drop increases?

The thing is simple: when we allow increased pressure drops on the fluid’s flow rate within an exchanger, and thus pressure drop of water circulating within the shell or the tubes, or on the two sides of a plate heat exchanger, we obtain a boost in performances. That’s because, being equal the section of the exchanger, increasing the pressure drop means that we are increasing the flow rate. Even better said, when we are accepting higher pressure drops, that means that we can reduce the passage section of the fluids and thus increase their flowing speed.

That leads to a more turbulent flow of fluids, which in the exchanger involves a higher number of collisions among the particles of the fluid and thus a higher thermal transfer rate. That’s why the thermal transfer efficiency increases too.

The same thing can be done for a pre-existing exchanger, where in order to boost the thermal transfer performances we can simply increase the flow rate, which correspond in quite a linear ratio to an increase of pressure drop and therefore of the performance of the heat exchanger.

This is a tiny good trick that is valid in the design of heat exchangers, both for plate heat exchangers or shell and tube exchangers, and for any kind of heat exchanger.

High pressure Brazed plate exchangers in CO2 refrigeration for transports

We’ve already spoken about CO2 refrigeration systems, a green and sustainable HVAC solution that not only eliminates the employ of synthetic refrigerants, but uses in addition a natural source, thus renewable and with zero environmental impact. The side product of CO2 refrigeration thermal cycle is indeed water.

For an application in HVAC for transport vehicles, both for the driving cabin and the passengers areas, Tempco has recently supplied super high pressure brazed plate exchangers, with a special design that enables the exchangers to withstand pressures up to 140 bar. The innovative HVAC solutions that employ CO2 for sustainable conditioning require indeed the employ of equipments and components especially designed for high operating pressure levels. A challenging new field of application for sustainable HVAC and brazed plate exchangers, that leads to new special engineering and construction deployments.

Tempco scambiatori saldobrasati alta pressione refrigerazione CO2

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Tempco TREG HCE monofluid thermoregulation in 3D model

Monofluid thermoregulation with TREG HCE thermoregulating units in cooling tasks is showed and ‘laid bare’ in this in video animation on our Tempco Youtube channel.

The video clearly showcases the flowing circuits in inlet of both the thermoregulated fluid and the cooling water. Once the thermal transfer is achieved within the plate heat exchanger, the unit provides the fluid regulated at the temperature requested by the process. The video clearly shows the fluids’ circuit scheme, with lateral views from both sides of the thermoregulating unit.


Furthermore, at the dedicated Solutions page in the Tempco website is also available an interactive 3D model of the thermoregulating unit, which allows to freely rotate the machine at any desiderd angle view and zooming in high resolution details prospects, offering the possibility to extensively explore the construction and engineering of these thermoregulating units.

Tempco TREG HCE monofluido modello 3D circuiti

Tempco TREG HCE monofluido modello 3D scambiatore

Tempco TREG HCE monofluido modello 3D raffreddamento

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Hot and cold extremes in automotive test bench

Thermoregulation is a key asset in test bench applications generally, and in particular for the temperature regulation system that in Tempco we have engineered for the testing tasks of automotive components of a customer. The system has to serve the test bench of automotive parts ensuring the regulation of temperature levels in a wide range, from -15° C up to +130° C.

The solution employs TREG series thermoregulation units, equipped with electrical heaters managed by thyristors. This allows to achieve an excellent adjustment of the thermal capacity, so that power consumption is strictly limited to the real demand of the testing process, ensuring in addition very narrow tolerances of temperature levels regulation.

Tempco termoregolazione banchi prova componenti automotive


The thermoregulating units are combined with TCHIL chillers, providing the cooling energy in order to complete the wide thermoregulation range in which the automotive components test bench works.

Tempco termoregolazione banchi prova componenti auto

Tempco termoregolazione banchi prova parti automotive


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Rise in energy prices and heating, switching from gas to electrification

The energy crisis, the rising of energy prices and the issues in gas supply from East caused by geopolitical problems of the conflict in Ukraine, are pushing companies towards electrification in their heating tasks in production processes. These issues are indeed increasing the prices for energy production, and therefore of heat.

The switch we are witnessing is from gas heating to electrical heating, as in Tempco we are receiving daily requests of this kind. This involves especially companies that have a self-production of electrical energy, coming from renewables such as photovoltaic. And in particular for big enterprises that have huge centralized systems that provide steam and high temperature diathermic oil for heating of production processes.

In fact, these companies are switching from this type of units to smaller units electrically heated. In the past, in Italy the cost of electrical energy was higher than gas, but actually the situation has turned, making this kind of choice preferable and more convenient, especially as said in case of self-production of power from renewables.

In addition, these kind of units allow to implement solutions using static relays or thyristors, thus allowing the adjustment of power consumption to the real request of heating in the production plant, limiting power consumption where is really needed. It is then possible to employ smaller units dedicated to heating of smaller parts of the plant, refining the energy consumption by heating only the process where it is necessary, instead of having a unique centralized heater serving all of the utilities at once.

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Refrigerators, PLC and inverter in precious metals refinery

Refinery and treatment of precious metals involve several critical points along the production process, which includes casting, melting and separation. Cooling systems are essential assets in the refinery industry, ensuring the right temperature regulation of the furnace and along the different steps of the refining process.

For a customer operating in the refinery industry of precious metals, Tempco has supplied a special plant served by refrigerators, that provide the cooling energy required for the thermoregulation of the production process. A pumping circuit, equipped with control of temperatures and flow rates using a PLC with operator panel and inverter for energy saving, conveys the cooling fluid to the different utilities within the refining plant.

Raffinazione metalli preziosi Tempco sistema raffreddamento

The cooling solution contributes to achieve the energy efficiency and sustainable production levels reached by the customer, that also widely employs solutions for automation, supervision and control of the production process.

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