Dry Coolers for large Data Center

Data Centres have high level of standards for operation. This applies also the cooling system, which has to be energy efficient without compromising reliability. Ekocoil designed and delivered Dry Cooler project with expertise and experience to one of the largest Data Centres in Europe. We worked in close co-operation with the customer throughout the whole project.

The starting point was design and dimensioning which meant precise optimization for the efficiency requirements, noise levels and energy efficiency. Several design data points were used to the most energy efficient configuration. This was done through different simulation rounds and computational analysis with our Optimizer software. A high V-model was the chosen design with high quality & high performance EC fans. This solution enabled lower fan speed and brought the most energy savings. Material choices, fan selection, fin spacing etc were all carefully considered and fully customized.

After the design phase a model heat exchanger element was manufactured in order to do a feasibility assessment on the functionality and plan production details. This is customary way of working for us, and it ensures a smooth delivery for the customer. The customized programming for EC fans was done in-house to get the most use of their technology. To maximize reliability, the Dry Coolers were programmed to operate stand-alone, so even with failure in the system, they would still run in fail safe -mode.

When the production was complete a series of FAT tests was executed to ensure that the efficiency requirements were met. Since the noise levels were especially strict, they were carefully tested. A comprehensive test run was done on individual units and as well as on the whole Dry Cooler field to ensure communication between them all.

The on-site delivery was strictly scheduled, so the whole logistic chain had to operate seamlessly. Ekocoil made the necessary arrangements and was on-site to guide and supervise the lift. Training was given for deployment.

Ekocoil products are highly durable and they provide long working life and reliable operation. Should there be any problems, we will be available for trouble shooting in short notice. We keep a wide inventory of fans, so a replacement can be delivered without delay.

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Thermodynamics and optimization

A short post would not even begin to explain the laws of thermodynamics. One thing is simple though – in real life 100% of efficiency in heat transfer can never be achieved. This is why dimensioning just the right kind of heat exchanger for each use case is imperative. This together with careful planning and skilful manufacturing will ensure that the best possible efficiency is achieved and also costs are kept under control.

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Optimized Heat Exchangers

So, though 100% efficiency eludes us, heat exchangers can nonetheless be dimensioned to achieve maximum performance by optimizing copious amounts of data for every application. For every heat exchanger and its operation conditions, there exists a solution that minimizes the amount of entropy, while maximizing the amount of heat transfer.

In addition to performance requirements and complex flow patterns, attention must be paid to size, weight and to cost limitations. And still, this is only a fraction of the inherent complexities of dimensioning the right kind of solution. Other things to consider are for example maintenance and cleaning, investment and operating costs, fouling and condensation.

The optimization process is never ending and it will keep evolving through experience and expertise. You should always take measurement and dimensioning data with a grain of salt and instead make sure you consult real experts for designing your heat exchanger. This way you will get a solution, that takes into account all the technical requirements and special considerations and combines these into one fully optimized package.

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Interested in learning more about optimized Heat Exchanger? Get in touch with Ekocoil experts.

Fouling in industrial heat recovery

There is still huge potential for energy saving through waste heat recovery in industrial spaces and processes. They create a lot of heat, which could be recovered and utilized. Many times, this is not case, though waste heat recovery and re-use would increase energy efficiency and create cost savings.

There are special requirements for using heat recovery equipment in industrial environment. They need to be durable and easy to keep clean. In industrial spaces, the exhaust air often contains different kinds of impurities, such as dust, oil mist or small metal flakes. These cause fouling in the heat transfer surfaces of the heat exchanger and thus reduced energy efficiency. Even a thin layer of dirt significantly diminishes the heat transfer capacity and the device may operate on a notably lower level of efficiency than originally planned.

Fouling in waste heat recovery is a problem, resulting in investment, energy and maintenance costs. The loss in annual efficiency rate may be as high as 10 % if there if there is fouling in waste heat recovery. This decreases the annual efficiency rate in ventilation by 8%.

The dirtier the heat exchanger gets, the more work it requires to get it clean. Designing the heat exchanger so that it easier to clean, usually results either in an increase in size or decrease in efficiency at the time. This obviously increases the investment / operating costs. These are factors, which should be considered when choosing and dimensioning the heat exchanger. The working life of the device is also something to keep in mind. A more durable device, which is easy to keep clean, will return the original investment through longer working life, through smaller maintenance and operating costs and through minimal down-time.

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Using Economizer to increase boiler efficiency

As requirements for energy savings tighten and costs become higher, every possible way to increase energy efficiency are more valuable than ever. In a boiler, a lot of energy is wasted with the combustion gas. Significant savings can be achieved, if this energy can be recovered and further utilized in the boiler cycle.

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Econimizers can be used for this type of heat recovery. It acts as a heat exchanger between the combustion gas and the feed water. Economizer is installed at the end of the boiler cycle to cool down combustion gas exiting from the boiler. The recovered energy can be further used to heat the feed water. This way the Economizer improves the operating efficiency of the boiler process.

Below is an example of the energy savings an Economizer offers.

Initial data:

  • Boiler efficiency: 5MW
  • Combustion gas from boiler: 200°C
  • Combustion gas from Economizer: 100°C
  • Energy cost: 50€
  • Operating time: 4000h/a

Results:

  • Economizer power: 257kW
  • Energy savings: 1029MW/a
  • Energy savings: 41466€/a

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The payback time for an Economizer is from 6 months to 4 years depending on case.

 

 

Basics of Heat Exchangers

Our company slogan says: ”Optimized Heat Exchanger Solutions”. But what does this actually mean? What is a heat exchanger? If you are an expert in the field, you are probably shaking your head to such a silly question, but I do believe there are people out there who do not live and breath heat exchange. And this post is for those people. So ladies and gents: here is a short introduction to the very basics of heat exchangers.

In short, a heat exchanger is a component for transferring heat between two mediums of different temperatures. The transfer happens either through conduction, radiation or through convection. Conduction and convection are probably the ones that don’t sound too familiar, so we’ll cover those briefly. In conduction, heat is always transferred from a higher temperature to a lower temperature, so from hot to cold and trying to even out the difference in temperatures. In convection, the heat energy is transferred away from the source of heat in a gas or liquid flow. This is caused by difference in temperatures, which in turn causes differences in densities. For example; think about how warm air always tends to rise upwards.

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Heat exchangers come in all kinds of shapes and sizes and their working principles are very different. They differ also in terms of use, flow pattern and the used transfer medium. As an example, we’ll cover the workings of a counterflow air to air heat exchanger. Quite a term, but it pretty much sums up the different features? In this type of heat exchanger, thin plates separate the airflows. When used in ventilation system, the other flow carries exhaust air from inside and the other one fresh air from outside. The two airflows never mix, but heat is exchanged between them, when heat from exhaust air is transferred to the cold outside air. As a result, the house gets a supply of fresh air with the proper temperature. In this case, plate heat exchanger helps to reduce the heat loss in ventilation, thus improving energy efficiency and reducing costs. Cleary a smarter way to get fresh air than just opening the windows. Which brings us to concept of annual heat recovery energy efficiency. Meaning how much of energy needed by the ventilation system can be covered through heat recovery. Plate Heat Exchangers have high efficiency, so they are good a choice to be used as heat recovery units.

The functionality of plate heat exchangers can be optimized and customized in several ways, for example adjusting the pattern in the plates or the spacing between them, but since this post was all about the basics, we’ll focus on them some other time. And though we didn’t even begin to cover them, all the products from Ekocoil Group are in fact some types of heat exchangers.

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