Heat exchangers, one of the hardest-working technologies in the engineroom, are rising to the low-emission challenge as they become more efficient and durable
One of the key takeaways noted by panellists during Riviera Maritime Media’s webinar Heat exchangers: the cold hard facts was that heat exchanger designs are steadily improving to meet new forms of propulsion. The event, held during Marine Propulsion Webinar Week in April, highlighted how repair and maintenance is evolving, too, with more advanced refurbishing processes giving existing units a new lease of life, and new methods that allow some units to be repaired on the spot, avoiding downtime and the expense of shipping units back to the original supplier.
“We are able to reverse-engineer solutions to ensure coolers provide longer service times and run efficiently,” explained AMI Exchangers marketing and sales communication manager Andrew Glover. “Most crucially, this provides benefits in fuel savings.” Although fuel savings vary according to a variety of factors, AMI expected its latest models to use about 6% less fuel compared with their predecessors.
The vital cleaning process can also be done much less expensively in situ, rather than requiring despatch to a distant service centre. Mr Glover said, AMI offers scrappage credits for heat exchangers that cannot be repaired economically.
“Scaled up across thousands of units, across thousands of vessels, the complete picture is vastly greener than it’s ever been”
Heat exchangers are however being worked harder than before because of the trend toward more compact enginerooms that require coolers to be placed much higher on the engine. “This brings its own problems, with many more coolers failing due to vibration and cyclic loading,” said Mr Glover.
Overall, though, he concluded, the steady development of heat exchanger technology continues to offer benefits to the shipping industry: “Scaled up across thousands of units, across thousands of vessels, the complete picture is vastly greener than it’s ever been.”
Agreeing with Mr Glover, fellow panellist RW Fernstrum president Sean Fernstrum said: “Emissions reductions has been a very big issue for us of late. We’re going to have to continue to deal with all this, as emissions reductions get tighter and tighter.”
The good news is that current heat exchanger technology can meet these challenges, including for all-electric propulsion, provided manufacturers are given adequate data covering heat loads and flow rates. “We’re moving into a more proactive stance rather than reactive,” said Mr Fernstrum. “I say that because, although we’re dealing with emissions now, you can bet that regulators and environmentalists are going to be looking for something else in the future.”
That ’something else’ could very well be water discharge. Mr Fernstrum believes however that closed-circuit cooling systems that eliminate discharges are up to the task. Closed-circuit systems are simpler, eliminating seacocks and seawater piping as well as expensive metals, such as titanium.
Encouragingly for manufacturers, heat exchanger quality is one of the key considerations in making spare parts purchasing decisions, according to a poll conducted during the webinar – 55% of respondents said ‘quality’ was a priority when selecting spare parts, with 20% noting ‘price’ and 25% ‘aftersales services’.