Tempco Blog articles

How to properly install multi-pass plate heat exchangers

20/03/2020

This week, let’s talk about mono pass and multi pass plate heat exchangers. Despite we’re used to see images of heat exchangers with the traditional four attachments on a single side, the front, there are also exchangers with attachments of two sides, both the front and the rear. These multi-pass heat exchangers have inside usually a particular scheme of the plates, called multi-pass design which involves a multi-pass flow control.

This multi-step diagram is employed in case we need very long thermal lenghts and very high temperature crossings, usually required in heat recovery applications. This sort of a ‘trick’ allows to stretch the plates, obtaining a thermal length of the plates a lot higher, in fact twice high compared to the height of the exchanger. This solution allows to push the recovery, that is the intersection of temperatures, up to very high limits.

On the other side, this solution brings some inconvenience, such as the pressure drops that will tend to increase. But it’s also true that those can be managed while designing the exchanger, by inserting them into the engineering software in order to compensate pressure drops by increasing the number of plates, i.e. the number of channels in parallel.

Another possible issue in case of a multi pass exchanger installation is the fact that it has connections on both the front and the rear, and it can bring some inconvenience. Having valves directly mounted on the rear side of the exchanger, when doing maintenance of the heat exchanger the pipes will make it difficult to access the rear stem to dismantle the plates, washing them, replacing the gaskets and so on. That’s why in case of multi-pass heat exchangers is suitable to install 90° curves on the rear connections, moving the valves outside the shape of the exchanger, so that during maintenance valves can be intercepted and the curves can easily be disassembled, gaining easy access to the rear stem.

One last issue that occurs with multi-pass exchangers is the fact that they cannot be boosted and upgraded without connection pipes adjustments.

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Atex thermoregulation for resins and chemical products

13/03/2020

Pictured here are ATEX thermoregulating skid units of reactors employed in the production of resins and other chemical products. This particular application saw maximum satisfaction of our customer, a company operating in the chemical sector, involved in the production of special adhesives largely employed in food industry packaging and the automotive industry.

Tempco termoregolazione Atex chimica

The customer previously used to employ a solution with direct jacket injection of steam and cold water. The implementation of our thermoregulating units solution gave excellent results, so that the company presented the case study with our skid units as a best practice to both the Group in the USA and the European affiliated companies.

Termoregolazione skid Atex

Tempco termoregolazione resine

Tempco centraline Atex chimica

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How to achieve energy saving in data center cooling

06/03/2020

High costs related to traditional data center conditioning systems can be eliminated thanks to free cooling solutions employed in immersion liquid cooling of IT equipments. This is a kind of applications that Tempco is strongly developing in collaboration with an important partner, with which we work since 10 years now, especially in the field of plate heat exchangers in the process industry sector.

Data centers are acknowledged for their high energy consumption, required in form of electrical capacity installed to feed the increasing demand of computing power, and also due to the high amount of heat generated by IT equipments. The heat generated is actually dissipated using classic conditioning solutions, using chillers and air/water thermal exchange batteries.

The new frontier being developed globally by such companies as Google, Amazon and Alibaba, that offers cloud data management services, is liquid cooling by direct immersion of electronic components of servers in dielectric fluids.

This innovative solution brings huge advantages, first of all in terms of temperature, that can be managed avoiding too many thermal steps. Electronic boards of servers can be indeed cooled down by direct immersion in dielectric fluids, avoiding the typical 3 temperature step required by air conditioning, freon/chilled water/cold air. This classic circuit requires indeed 3 steps, using chillers to cool down water, glicol water to cool down air and the cold air that finally cools down the electronic components.

Liquid cooling in data centers allows to dive the electronic boards in direct contact with the dielectric fluids. Leveraging on higher heat dissipation rate of fluids compared to air, liquid cooling also affords to work with less-low temperatures, allowing to employ free cooling systems to cool down dielectric fluids, avoiding the use of freon compressors and chillers, thus obtaining enormous energy savings.

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Heat exchangers corrosion in salmon farming

28/02/2020

Recently we’ve been contacted by a leading salmon farming, in search of new plate heat exchangers to maintain the fresh water in their salmon’s aquaculture plants.

allevamento salmoni

The customer employs a recirculating aquaculture system technology, with water filtered sevenfold and recycling of all the waste. Fish grows in melted snow water in a closed circulation system that reduces the need for fresh water to below 2%, by filtering and cooling the 98% of it, ensuring a healthy environment without use of chemicals or antibiotics.

The salmon aquaculture requires salty water, that causes corrosion on the exchangers’ plates made in AISI 316 previously mounted. In addition, the previous supplier of the cooling system installed the plates in a wrong way, making the problem even worse.

Tempco plate heat exchangers corrosion

We thus developed a new cooling system which employs titanium plate heat exchangers, in order to ensure that recycled water has the necessary low temperatures and avoiding corrosion on metal heat transfer plates.

scambiatori calore allevamento salmoni

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How to calculate the amount of heat to dissipate in hydraulic power units

21/02/2020

In hydraulic power units, a system with a pump pushes the hydraulic oil under pressure inside the servomechanisms and pistons. The oil thus increase its temperature, and requires to be cooled in order to maintain its characteristics and proper operating conditions.

To provide the suitable hydraulic oil cooling in hydraulic power plants, in Tempco we install a lot of plate heat exchangers.

How to calculate the amount of heat to be dissipated from the hydraulic oil circuit?

First of all, the hydraulic oil must be regulated at a suitable temperature between 40 and 50° C, in order to properly feed pumps, cylinders and hydraulic motors. The thermal heat to dissipate is then calculated considering the power of the motor engine of the pump, that provides the circulation under pressure of the lubricating oil within the hydraulic machinery. This is indeed the element that transfers thermal power to the hydraulic oil.

The exact amount is obtained by calculating the 30 or 40%, at maximum 50%, of the power of the pump’s motor. This will be the amount of thermal energy to be dissipated from the hydraulic oil, to cool it and maintain it at the correct temperature to preserve its functions.

This is an empirical method, because there are other factors to consider such as the yield and efficiency of the pump and the electric motor. But usually this method is employed to simply determine the amount of thermal power to dissipate from the hydraulic oil. To make an example, if we have a pump with a 100 kW motor, the amount of thermal energy to remove from the hydraulic oil circuit is between 30 and 50 kW.

There is another essential factor to be considered, being the viscosity of the oil, and we’ll soon dedicate to this important topic another video.

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The big rise of immersion liquid cooling in data center market

14/02/2020

A huge main trend is going on in the data center sector worldwide, moving forward boosting energy saving and related to the adoption of immersion liquid cooling solutions., which in Tempco have been already developed using TCOIL dimple jacket exchangers.
Giants in the field of IDC infrastructures on the Chinese market are already implementing immersion liquid cooling solutions since a few years now, achieving relevant energy savings along with a series of other advantages, compared to traditional air cooling systems.

We have already introduced the concept of PUE, defined as the ratio of the total amount of energy used by a data center facility to the energy actually delivered to computing devices. Today the PUE value is an important cost factor, even though not the only one, that data center architects must consider when evaluating the energy efficiency of an IDC, also becoming a necessary condition for compliance. Best practices already operating since 2018 demonstrate that the switch to immersion liquid cooling solutions can increase the energy saving by 12,8% in a data center, reducing PUE value under 1,09.

The achievable saving is even higher, because a liquid cooling system in data centers eliminate the use of server fans, increasing the energy efficiency up to 21,5% and reducing noise levels inside the IDC, turning it into a very quiet and efficient environment. Even more important is the benefit offered by the switch from air to liquid as heat dissipation fluid: liquids have indeed a higher heat dissipation rate compared to air. Thus the main advantage of immersion liquid cooling is that it allows to use a fluid at less low temperatures compared to the low temperatures required by air-cooled IDC scenarios. High capacity compressors of chillers can thus be eliminated, leading the way to the use of free cooling systems with significant energy saving on utilities such as chillers and HVAC.

In order to give an idea of the energy saving granted by a liquid-cooled solution, let’s make the example of a chiller that supply refrigerated water at 10° C with a thermal work of 105 KW and ambient air at 30° C. The compressor employs a 30 KW electric motor + pump (2,2 – 3 KW) + fans for the air condenser (approx. 4 KW). By eliminating the chiller using a free cooling solution, it will remain the pump and the fans’ power (maybe with a slight increase for the fans, by +5/10%), but the high power consumption of the compressor is completely eliminated.

In liquid cooling of IT equipments, the use of brazed plate heat exchangers also allows to separate the dielectric fluid from the cooling water, with a very narrow loss of temperature, thanks to the efficient thermal exchange rate of plate heat exchangers.

Further on, in liquid cooling of an IDC the value of PUE no longer depends on changes in the weather area of installation, so that the site selection for the data center can be based on its own business needs. In a liquid-cooled scenario the server is also sealed in container due to isolation, avoiding the effects of humidity, temperature and dust on electronic components, dropping the failure rate of hard disks by about 50%.

Immersion liquid cooling, using horizontal cabinets, also makes wiring easier to standardize. Some projects are also on development for robotic arms that support engineers and operators in liquid-cooled IDC by lifting equipment for routine maintenance, filling and replenishing operations.

Data center liquid cooling clearly requires a re-design of electric components and a proper selection of constructive materials employed, in order to be suitable for direct contact with the various kind of liquids that can be selected. Air cooling and liquid cooling will thus likely coexist for a long time still, but the proportion of immersion liquid-cooled solutions will gradually increase.

By the way, the number of data centers around the world is constantly raising up, in order to satisfy the increasing computing power demand caused by the increase of big data amount, AI applications, cloud and edge computing, 5G. More and more, data centers will have to ensure higher energy efficiency and power savings, in great part relying on IDC infrastructure cooling costs, leading the way to a bright future for liquid cooling solutions.

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How to select heaters in thermoregulating units design

05/02/2020

A new video on our Tempco YouTube channel is about the selection of electric heaters in thermoregulating units.
The range of Tempco’s Treg thermoregulating units enables to regulate the temperature of fluids employed in industrial processes, in a wide temperature range from -20° C up to +300°C. Depending on the temperature level required, the units work using different thermal fluids, such as glycol water, diathermic oil or silicon oils.

Electric heaters are employed to heat up the water or the oil, aimed to work as thermal vectors when other heat sources are not available, such as steam.

Their function is very delicate, as they have often to heat up fluids with significant thermal capacities, but at the same time they have to preserve to fluid to be heated. At this purpose, there are some critical temperature limits for the fluid that must not be surpassed. The value to consider is the surface temperature of the heater at its contact with the fluid.

Diathermic oil requires in particular lower surface temperatures of the heater, in order to avoid the cracking of the oil itself. When carbonized, the deteriorated oil creates a coating on the heater surface, lowering its thermal conductivity and heating efficiency, also leading to collateral effects such as the burn or short circuit of the heater.

Heaters must thus be sized according to a very low specific heat, that is watts dissipated by cm2, using specific charts during the design of thermoregulating units, in order to maintain heater’s surface temperature within the values allowed for the fluid employed. Temperature sensors are thus integrated inside the heaters, in direct contact with the external surface of the heating element checking its surface temperature, limiting the functioning when design limits are exceeded.

Heaters can have different shapes and be made in several materials, such as carbon steel, copper and stainless steel, according to the kind of fluid they are supposed to work with. In our Treg thermoregulating units we employ custom made cored heaters, with very low surface temperatures and specific heat.

A low specific heat requires a greater surface, meaning bigger heaters and higher costs in order to achieve the temperature needed. Nevertheless this measure ensure a longer service life for the heater, and therefore a longer service life of the thermoregulating unit, resulting in important savings in the long term.

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Thermoregulating units for hazardous area ratings in USA

31/01/2020

Our Tempco thermoregulating units are often supplied to customers that operate in Atex environments, aimed to work in hazardous explosive atmosphere such as in chemical and pharmaceutical sectors. An example are these thermoregulating units for filter dryers and reactors that we’ve supplied to a North American customer a few months ago.

In this case, USA regulations required the thermoregulating units to be in execution compliant with hazardous area ratings FM IS / I / 1 / ABCDEFG simple apparatus, if installed per MS50-0923/NC (intrinsically safe).

Class 1 – Division 1 – Groups C&D
Class 2 – Division 1 – Groups F&G – T3C

This is the USA equal to our Atex Directive. The thermoregulating units are equipped with automatic/pneumatic valves, motor and pump all compliant with the above regulations.

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Immersion cooling at the Marina di Loano Seaport

24/01/2020

Heat pumps, TCOIL dimple jacket exchangers and in depth cooling leveraging water temperature of the sea. Or lake water.
We explained in the past months some heat pumps cooling applications we have developed that employ the low temperatures of sea or lake water available in order to dissipate heat produced by the operations of heat pumps.

The application gets interesting thanks to the use of special immersion plate heat exchangers, able to work in direct contact with sea water, as it is in the installation we’ve made last July in a seaport in Liguria. Once closed the season, we have received an enthusiastic feedback from our customer, being the Marina of Loano, a beautiful modern tourist port in the Italian Liguria region.

The substitution of traditional heat exchangers with the new immersion dimple jacket exchangers allowed indeed not only to avoid the problems of clogging that occurred to the old cooling system, but the customer also says that it allowed to achieve an energy saving of 40 euro/day, thanks to the implementation of the new kind of immersion cooling heat exchangers. A great satisfaction for both sides!

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How does it work a centrifugal pump?

17/01/2020

Back on track with our Tempco tutorial video series in this new year, let’s talk about fluid motion, being it water, oil or other kind of fluids. In particular let’s talk about how a centrifugal pump works.

A centrifugal pump is a hydraulic machine in shape of a rotative pump, that can be directly coupled with an electric motor or via a joint. As it often happens, Tempco customers ask how centrifugal pumps should work in order to operate properly ‘in range’.
If we look at a common functioning curve of a centrifugal pump, flow rate and pressure values happen to be inversely proportional: when flow rate is at its maximum the pressure is minimum, viceversa maximum pressure corresponds with minimum flow rate.

With the outlet of the pump completely closed, with water delivery off, we’ll thus have maximum pressure value. Customers often contact us telling the pump is undergoing a huge effort while pushing water at a high pressure. If we take a look at the electric power absorption curve of the motor, we’ll see that the power input of the electric motor is inversely proportional to the pressure value generated by the pump.

Otherwise, a maximum pressure value is combined with minimum power consumption of the electric motor, which instead goes maximum when the pressure is at its minimum.
The reason relies upon the mechanical functioning of a centrifugal pump, which moves the maximum flow rate when the pressure is at its minimum, pushing high weights of fluid putting the electric motor under big efforts, meaning high power consumption.

To make an empirical example, the same happens when we try to move a huge weight for a short space distance, it takes a very big effort.

The consequence is that in case the decrease of pressure gets no limitations, letting the pump operating without pressure charge, the pump will exceed its operating range, triggering the intervention of the thermal protection of the electric motor.
Pumps have indeed a limit toward upper pressures, since they cannot exceed a certain maximum pressure, but on the other side they can push flow rates much higher than the design value of the electric motor, setting the motor in out of range stress, that causes the intervention of the thermal protection to avoid the burn out of the motor itself.

To avoid this issues, in our plants we usually put a gate valve on water delivery, which increases the pressure while closing it, making the pump operate back in the correct range, with proper design flow rates, thus ensuring that the motor won’t absorb power in excess.

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