R449A-based marine refrigeration system for a 65m super yacht

Chillflow Solutions Ltd has designed and installed a bespoke R449A-based marine refrigeration system for a 65m super yacht, operating on high efficiency BITZER ECOLINE compressors.

The ocean-going ice-breaker required a highly reliable replacement refrigeration system to serve its onboard cold room, freezer and garbage store.

Use of an off-the-shelf replacement pack was ruled out due to space restrictions, and the distance between the pack, cold rooms and condensers. The system also required 100% redundancy to ensure continuity of cooling in the unlikely event of a breakdown at sea. 

Chillflow Solutions Ltd went back to the drawing board to design a totally bespoke solution, with support from BITZER UK. The resulting system, built at the refrigeration specialist’s Redruth site, has a capacity of 12kW and is based on two BITZER ECOLINE 4PES-12Y semi-hermetic compressors operating on a run and stand-by basis, each able to cover the cooling load and operating with a condensing temperature of 45deg C.

R449a refrigerant is non-toxic and non-flammable, with an A1 safety classification under EN 378 and ASHRAE 34 standards.

The compressors have an integrated monitoring system that keeps track of winding temperature, phase sequence, phase failure, current, plus oil temperature and level, ensuring optimum performance at all times.

The pack is connected to two Bitzer sea-water resistant K373HB shell and tube condensers, which provide excellent corrosion resistance and heat transfer between the refrigerant and sea water, used to reject heat.

Darren Mockridge, Managing Director of Chillflow Solutions, said: "The time-window to complete the project was tight due to the vessel’s limited time in port. It was crucial to have a proven, water-tight design ready to go from the moment the installation team had access."
He added: "Our relationship with BITZER UK goes back many years. However, this was our first direct project collaboration with the company, via the local distributor. The team was extremely supportive on the technical aspects and helped us deliver a reliable, highly efficient bespoke solution."

A key design requirement was optimum energy efficiency given the limited power availability onboard. The pack uses BITZER CM-RC01 controllers to regulate the compressors’ VARISTEP capacity controls, allowing refrigeration output to be precisely matched to cooling load, down to 10% of full capacity.

The pack is also equipped with a BITZER IQ module with Bluetooth connectivity, giving hands-free access to key performance parameters, if required.

Darren Mockridge: "The close relationship between BITZER UK and its remanufacturing arm, Green Point UK, is also a big plus for us – not just in the UK but worldwide. For example, our operation in Australia works with the local BITZER and Green Point remanufacturing divisions there to support our Australian marine contracts."

Kevin Glass, Managing Director of BITZER UK, said: "Marine refrigeration applications are particularly demanding due to the critical nature of onboard cooling and challenging marine environment. ECOLINE compressors are proven to give long-lasting service in harsh applications, such as marine cooling.

"We were delighted to support Chillflow Solutions in their innovative solution for this project, which was delivered successfully despite the tight timeframe and restricted access onsite."