Tempco Blog articles

Drift separators in cooling towers

22/11/2019

Third episode on our video series focused on cooling towers components, this time is the turn of drift separators. Drift separators are components employed in cooling towers to limit water consumption, installed above the nozzles that provide the distribution of water. These components are intended to capture all the water droplets that otherwise would be drafted away by the air flow generated by the forced ventilation coming from fans inside the evaporative tower.

Construction materials are similar to those employed for filling packs, being traditional plastic materials such as PVC and polypropylene.
Thermoformed droplets eliminators is the most employed typology. Also parallel fins separators do exist, but they offer slightly lower efficiency and are usually employed in other types of separation systems, not really much in evaporative towers. In the past, droplets separators used to be made in wood, but nowadays this is an obsolete kind of construction no longer employed.

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Ferrari intercooler, some ‘dirty trick’ cooling?

15/11/2019

Rivals teams in F1 are moving forward some doubts about the legality of the cooling system in the Ferrari power unit. That’s what this interesting article I found online is talking about. These are just hypothesis, nothing has been proved, but the presumed anomaly should refer to the employ of oil within the intercooler which cools down the intake air coming from the turbocharger and aimed to increase the output of the internal combustion engine.

An intercooler is a heat exchanger, usually air/water or air/air type, installed between the turbocharger and the combustion engine. Its function is to cool intake air charge, increasing the efficiency of the combustion. The turbocharger compresses the induction air employed in internal combustion engines to improve their volumetric efficiency. As a result, the compression process raises intake air temperature while reducing its density. The intercooler removes the heat of compression decreasing intake air charge temperature, sustaining the use of a more dense intake charge into the engine, increasing the output of the power unit. In addition, the lowering of intake charge air temperature also avoids the danger of pre-detonation.

The cooling circuit of an intercooler is composed by a quantity of tubes, a grid of micro-channels in this case, where a fluid flows, usually water. As it happens in every heat exchanger, the intake air charge flows within the grid giving up its waste heat to the fluid, cooling itself.

Rival teams of the Ferrari are supposing that the intercooler of the Ferrari could be employing oil to achieve the cooling of the intake air charge. The use of oil is not prohibited, unless it evaporates leading to a contamination of the intake air charge directed to the power unit. The insertion of oil in the combustion engine boosts the performances of the combustion process, a practice that has been forbidden by the FIA technical regulations.

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Filling options in cooling towers

08/11/2019

Chapter two in the cooling towers components saga. Let’s face the types of filling elements, which is the component within which happens the cooling of water. It is possibile to divide the typology of filling systems in two large families, film filling and splash filling. As the name itself tells, in film filling water flows along the walls of the filling pack creating a water film, increasing thermal exchange surface for direct thermal transfer between the flowing film water and the air rising up in countercurrent. Splash filling provide instead the spreading of the water flow distributed by nozzles in many droplets, increasing that way the direct air/water thermal exchange surface.

Materials: both systems are made of plastic materials. Film filling can be in PVC or polypropylene, splash filling is usually realized in form of polypropylene grids.

Efficiency comparison: film filling offers a higher thermal transfer efficiency, thus at equal water load and thermal capacity a splash tower solution will be bigger and more expensive than a film tower. Otherwise, in case of dirty water, containing polluting particles and filaments, a splash filling is preferable because it won’t clog, while a film filling can easily get clogged requiring periodical maintenance or even the substitution of the filling packs in order to restore the cooling efficiency of the evaporative tower. If the maintenance interventions happen within intervals of years, a film filling system can be an affordable solutions still, but in case of a very dirty fluid to be cooled that leads to cleaning or substitution within days or weeks, a splash filling solution is the only one possible.

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Thermoregulation Atex skid package units

05/11/2019

The thermoregulating units developed by Tempco for the temperature control in Atex environments are supplied as package skid units ensuring maximum flexibility, with remote management option and compete with certifications required for industrial environments with explosive atmosphere, tipically in pharma, chemical and oil & gas plants.

The engineering of equipments for this kind of environments, in presence of air gases, vapours, mists or dusts coming from the processed products, requires a series of precautions, from the selection of constructive materials Atex compliant through the evaluation of the temperature class.

Temperature classification defines in particular the maximum surface temperature that a machinery, both thermal or electrical, can reach when installed in explosion risk environments, that Tempco evaluates with maximum attention together with the final user. In depth, the temperature class impose that the maximum surface temperature must always be lower than the auto-ignition temperature of the flammable substances in the working environment. The Atex equipments employed can thus include an Atex thermostat for maximum temperature, an Atex pressure switch for maximum pressure check and an Atex temperature sensor.

Also the assembly of components of an Atex skid unit requires some peculiar care. The equipments are intended to thermoregulate fluids, often diathermic oil at high temperatures, so that is crucial to ensure the perfect seal of junction points, because leakage can become a critical issue in hazardous and explosive atmospheres. All the internal connections in the skid unit are flange joints and/or welded. All the gaskets on the flanges can employ spirometallic gaskets, while seals on the instruments, when welding is not possible, are metallic to avoid any possible leakage.

In addition, the flange connections are not only intended to avoid oil leaks, a very critical event in case of Atex environments, but also allow an easy installation. Flange connections provide indeed the guarantee of correct installment values, while with threaded connections one or two thread rotations are enough to get off quota, in addition to the risk of oil leaks. Finally, usually the construction material is stainless steel, in order to ensure maximum corrosion resistance in aggressive environments.

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Nozzles and water distribution in cooling towers

25/10/2019

New On-the-road video today, back to Cooling towers, and we’re talking about the components of cooling towers in particular.
Let’s focus on the water distribution system on filling packs on evaporative towers, that ensure the thermal exchange in the system. Package towers usually are equipped with a pipe distribution system connected to nozzles to spray water on filling packs.

Focusing on nozzles, there are nozzles of various shape and size, depending on the load of water to distribute. Nozzles with very low pressure drop and a good distribution pattern are usually employed, and at the same time they must be no-clogging in order to avoid the deposition of scaling and debris contained in the circulating water.

Materials of nozzles can be various, there are plastic nozzles but also made in metals, usually stainless steel, often employed in huge concrete cooling towers.

Big concrete cooling towers don’t have a pressured distribution system, having open channels leveraging water gravity distribution. Thus, nozzles employed here have bigger size and even lower pressure drop, in order to ensure that the distribution system can work even with very low pressures of the water flow.

This is not the case of package towers, where incoming water has often high pressures that is suitable to be reduced to avoid a bad and irregular distribution pattern.

There are indeed, at last, also special nozzles that provide a three phase distribution, ensuring an ideal water distribution on the filling pack, essential to guarantee the best cooling efficiency of the evaporative tower.
Ventilation and the kind of filling packs will soon be object of further videos.

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Energy saving, EC motors and cooling

18/10/2019

Let’s present today a retrofit solution developed for a supermarket, where traditional AC motors have been replaced with electric EC motors that can be regulated with 0-10 V signal. The substitution has been done on the totality of refrigerated counters, evaporators and chillers employed in the supermarket.

The installation of electric fans with EC motor and external rotor granted significant advantages, first of all allowing a reduction in power consumption, with an annual saving of 138.970 kWh, approx 1/3 of the amount of energy previously consumed by AC motors.

Despite a higher initial investment, the installation of EC motors had thus a second relevant benefit, due to the fact that this kind of technology doesn’t require maintenance costs, while maintenance costs for 10 years of operations on AC motors can be calculated in 72.000 €.

The retrofit substitution of AC motors with EC motors on the totality of refrigerated counters, evaporators and chillers in the supermarket granted then an annual saving of 21.527 €.

In this specific application, considering an energy cost of 0,11 €/kWh, the comparison for the totality of equipments is as follows:

Overall costs AC motors in 10 years:
– 12.800 € initial investment
– 72.000 € maintenance
– 381.568 € operating costs

Total amount on 10 years: 466,368 € – annual cost of 46.637 €

Overall costs EC motors in 10 years:
– 22.400 € initial investment
– 228.701 € operating costs

Total amount on 10 years: 251.101 € – annual cost of 25.110 €

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Heating and cooling load calculation in pharma thermoregulation

11/10/2019

A special video on the road today, to explain how to calculate the heating and cooling load, that is the amount of thermal energy to be added or removed to a certain production process in order to achieve a required temperature regulation. In this case we face the problem applied to the heating or cooling load for a thermoregulating unit on a pharmaceutical reactor.
There is a wide range of machinery and equipments in use in the pharma and chemical industry, and the calculation method of the heating and cooling load depends on the kind of machine employed.

Anyway, the most common way is to consider the volume of the reactor to be thermoregulated, and the physical properties of the kind of product processed, in particular its specific weight and specific heat capacity. Following, the heating and cooling curves required by the application must be known, that is the starting and final temperatures to be reached, and the time frame required to complete the heating and cooling cycles of the products.

At this point the calculation is obtained with a simple formula, multiplying the volume of the product x specific weight x specific heat capacity, multiplied x the temperature change, and all divided by the time unit. The resulting are the kcal, or kw/h required to heat or cool the product. The formula must then be applied to all the up and down temperature ramps, to find out the most challenging one that will serve as base for the correct sizing of the thermoregulating unit.

Another case is represented by the distillation of products. In this case the reference heat or cooling load to determine the size of the unit is obtained, in addition to the temperature ramps calculation, by another one related to the distillation process, multiplying the amount of kgs/hour of distilled product x the latent heat of vaporization.

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Thermoregulating unit in pharma sector

04/10/2019

The thermoregulation unit in these photos has been designed for application in the pharmaceutical sector. It is quite a standard solution, with heating circuit employing steam and brazed plate heat exchangers in AISI 316/copper. The cooling is achieved with chiller water. The temperature tolerance ensured is +/- 2° C.

The unit is equipped with double automatic stand-by pump, and completed with remote management function of the set-point.

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Water cooling essentials in a cooling tower

27/09/2019

Cooling towers are lean and simple machines aimed to cool down water employed in industrial production processes of any kind. These are simple machines because the only component moving is the electrical fan, and the cooling process is achieved through a direct air/water contact heat exchange, without exchange pipes.

The water to be cooled enters in direct contact with the air in the cooling tower, allowing the water to be cooled at a lower temperature compared to the environmental air temperature.

This is achieved thanks to the latent heat of vaporization that brings a wind chill effect, taking advantage of the amount of water that evaporates in direct contact with air, removing calories. The amount of heat removed by water’s evaporation is a relevant amount, called latent heat of vaporization, and is equal to about 550-600 kilocalories per kg of water evaporated.

And so, a cooling tower is a machine that allows to cool water in a very efficient way with a contained energy consumption. On the opposite, there is a consumption of water, dissipated due to evaporation, that must be reintegrated in the circuit in a greater quantity than the quantity of water dissipated, in order to dilute the concentration of salts obtained as a consequence of the evaporative process.

The reference temperature for the cooling potential that can be achieved in a cooling tower is the wet bulb temperature, that is the environmental temperature measured with a thermometer with a moist bulb. Usually, wet bulb temperature in a city like Milan, for example, is 26° C in the worse conditions, in July, when ambient temperature rises up to 35-36° C. In these conditions, the wet bulb temperature is 10° C lower than environmental temperature, so that it’s possibile to cool down water at a temperature 3-4° C higher than wet bulb temperature, depending on the design and sizing of the cooling tower.

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Thermoregulation unit in pharma lab

20/09/2019

The processing of pharma products requires well defined temperature loops that must be thermoregulated, as we’ve already faced the argument in many other occasions. Recently, we’ve supplied a new thermoregulating unit for a pharma lab, intended for heating and thermoregulation of injectable solutions.

The thermoregulating unit is employed for laboratory tests and production, combined with an equipment that forces an injectable solution to achieve a defined thermal cycle.

The main target of the application is to obtain high precision temperatures and to maintain them within a strict range of tolerances that can be programmed/setted-up.
The solution is completed by a remote interface for the recording with data log of the results. The thermoregulation unit is in full inox execution for employ in pharma environment.

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