HVAC FEATURE Are heat exchangers being overlooked when it comes to energy efficiency?


Andrew Peacock, service manager, Energy Division UK & Ireland at Alfa Laval, addresses the apparent increasing issue of run-to-fail attitudes and the impact this could be having on energy usage


A SUSTAINABLE APPROACH TO PLATE HEAT EXCHANGERS


not fully optimised and could be draining businesses unnecessarily.


AN EFFICIENT EXCHANGE Gasketed plate heat exchangers (GPHE) are the most common type of compact heat exchanger. They are often used for food and drink processing, chemical production, and heating and cooling purposes. In a GPHE, the metal plates are fitted with elastomeric gaskets which seal and direct each fluid into alternate channels. Hot channels will be placed against cool channels with each fluid flowing counter or co-currently to facilitate thermal transfer. The aforementioned features mean


The International Energy Agency recently tracked clean energy progress in relation to the COVID-19 pandemic, explaining that while we are seeing an inevitable temporary decline in overall industrial energy consumption, the crisis itself could impede clean energy transition progress


I


t’s an undeniable fact of the 21st century that we need to use less


energy – it’s how we get there that’s open to discussion. Of course, the impact of COVID-19


appears to have temporarily accelerated the country’s energy transition with less movement of people, an increase in renewables, and considerable slowdown in industrial activity. In fact, the International Energy Agency


recently tracked clean energy progress in relation to the COVID-19 pandemic, explaining that while we are seeing an inevitable temporary decline in overall industrial energy consumption, the crisis itself could impede clean energy transition progress. This is mainly due to new tighter margins and fewer scalable technologies to abate emissions, as companies try to remain financially buoyant and revive production levels. Consideration must therefore be given to the low hanging fruit – i.e., the incremental changes that can be made in our day-to-day operations. This is where plate heat exchangers


(PHE) come in. Subject to an industry- wide misconception that they are ‘simple’ components, PHEs are often overlooked as a key to improved efficiency. At Alfa Laval, we estimate there are thousands of PHEs – of all brands and sizes – in operation that are


GPHEs are prized for their high efficiency rate afforded by a large surface area, and are up to five times more efficient than alternative technologies such as shell and tube heat exchangers. They have a versatile and small footprint and also enable waste-heat recovery. Depending on manufacturer, the latest designs enable improved thermal efficiency, media flow and minimise risk of fouling – something Alfa Laval has been prioritising for years. Not only is design crucial to efficiency,


but these components also often feature within modern efficient heating methods such as cogeneration and district heating systems. As many will know, combined heat and power (CHP) is one of the most efficient methods of energy utilisation – over 90% of energy can be channelled back into efficient use. It is a highly cost-effective solution that brings many benefits. And with regards to district heating, this reliable and eco-friendly heating delivery method offers the flexibility to tap into a variety of heating sources, including energy from renewable or recycled sources. A no brainer for improving energy


efficiency, wouldn’t you say? However, just having a GPHE in place isn’t enough.


SO WHAT COULD BE THE PROBLEM? While GPHEs are durable, issues still occur with regards to fouling. This can


/ ENERGYMANAGEMENT


drive up the energy required to process a medium, costing a business more money and raising a plant’s carbon emissions. In fact an academic report from 2015 stated that numerous studies have shown that heat exchanger fouling may be responsible for 1-2.5% of global CO2


emissions. Fouling is caused by the settlement


of particulates, biological matter, formation of scale, decomposition and crystallisation. These unwanted deposits create an insulating layer that lowers the efficiency of heat transfer between two fluids. Despite the fact that GPHEs have a


self-cleaning effect due to the turbulent flow inside the channels, it is crucial to be aware of the fouling status in order to retain high thermal efficiency.


WHAT CAN ENERGY MANAGERS DO? Less-than-ideal operating conditions will raise an organisation’s energy consumption across the whole process, energy spend and carbon footprint. In order to mitigate the issues discussed here, energy managers need to consider the incremental changes that can be made. However, while fouling is easily


identified, other damage will be much harder to determine without the right tools. Therefore it makes little sense to leave a crucial part of production to those with only rudimentary knowledge, especially when damaged or fouled components have such a profound impact on a business’s ability to remain competitive. By consulting an expert team to provide regular in-field analysis to detect problems at their earliest stages, energy managers can avoid the false economy of a ‘run-to-fail’ approach, playing their part in improving efficiency to make future savings. To find out more, download Alfa


Laval’s full report ‘Fit for Duty’: www.alfalaval.co.uk/fitforduty


Alfa Laval www.alfalaval.com


ENERGY MANAGEMENT | WINTER 2020 23


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36