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The paradigm shift to ‘light and might’

Remember the shift from large and heavy desktop computers to flexible laptops? In the span of a few years, technological advances allowed people to achieve the same – or more advanced – work with the substantially smaller laptop. The advantages are obvious: laptops are more compact, offer the same high performance, are lighter and easier to handle and maintain. What if the same thing has just happened within the field of heat exchangers for District Cooling?

| | Feb 2, 2017 | 10:39 am
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– By Pär Björkman

Pär Björkman

We are currently juggling between environmental concerns and the fact that an increasing number of people all over the world are seeking to improve their living conditions. District Cooling is part of the solution. Within District Cooling, the gasket plate heat exchanger (GPHE) has been the most common one for decades. However, GPHEs are large units, have gaskets and need to be cleaned and maintained. And when gaskets fail, they leak, which can lead to additional costs for maintenance, replacement or clean-up.

A brazed plate heat exchanger (BPHE) is a gasket-free heat exchanger, assembled using brazing technology. The technique creates a compact, low-maintenance and durable unit with high operational dependability. To some, the compact size of the BPHE meant that the technology could not reach the higher load capacities required in District Cooling systems. That is no longer a concern. Similar to the computer revolution, with its swift shift from desktops to laptops, the BPHE technology has seen incredible development in recent years and is able to offer smaller and more efficient systems with similar, or even greater, capacity.

Today, we are witness to single high-capacity BPHE units, which can offer up to 1.5 MW cooling with 25 bar as standard pressure rating. Highly turbulent flows, created by the corrugated channels, enable small temperature differences in the media to be used most efficiently. Even at these high capacities, the BPHE remains compact and light and, consequently, is easy to install. With less than 50% of the weight compared to a GPHE, a BPHE can easily fit through a standard door or elevator and requires little space on site. This allows for easy retrofitting and installation in buildings with limited space. The BPHE also allows a modular design with a plug-and-play approach, thanks to its compact design, which is the same concept as for modular chillers. This offers another type of redundancy.

The high capacity Brazed Plate Heat Exchanger (BPHE) is installed with minimum use of space.

Gasket-free means maintenance-free. Since a BPHE is brazed together, it does not have any gaskets, frames or bolts that need to be replaced. As a result, there is no maintenance needed, such as tightening the plate packages or servicing the gaskets, which minimises downtime and decreases the number of man hours. A BPHE is an investment in low lifecycle cost and also an investment in the future. More than 95% of a BPHE is used for heat transfer, offering a unique combination of efficiency, small footprint and swift installation. Estimated at 15 to 20 years, the lifecycle cost of a BPHE, including energy, maintenance, spare parts and labour, can be half of the lifecycle cost of a system that uses the GPHE technology.

The compact size demands less floor space and the modularity allows for easy expansion, if required. This is a dream come true for planners, architects and constructors, as the BPHE can easily be added, or extended, if necessary. The compact size of BPHEs allows installation space to be used more efficiently. Larger systems can be installed unit by unit, which eases the installation process and simplifies capacity expansion when demand increases. Owing to their compact size and versatility, BPHEs can be combined with standard components to create a District Cooling solution that can meet the specific needs of the end-users.

Pär Björkman is Segment Manager for District Energy, SWEP International. He can be contacted at par.bjorkman@swep.net.

CPI Industry accepts no liability for the views or opinions expressed in this column, or for the consequences of any actions taken on the basis of the information provided here.

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