Custodian Selects Aqua As Premier Cooling Partner For Integrated Free Cooling System

The Client –

Custodian Data Centres

The Challenge –

Cooling System For New 10MW Data Centre Facility

The Solution –

Highly Energy Efficient Closed Loop Air Cooling System, Incorporating Integrated Free Cooling Chillers

Custodian Data Centres, the UK’s leading colocation provider for MSPs, cloud, enterprise and digital entertainment organisations, enlisted Aqua to design, supply and install an innovative temperature control system at their new 10MW site located in Dartford, Kent.


With Custodian’s award-winning Maidstone facility nearing capacity, Custodian commissioned its new ‘DA2’ facility in Dartford, Kent, to meet the continued growth demands of its customers. Less than 15 miles outside of Central London, Custodian’s goal was to provide an advanced facility for end-users to relocate and host their mission-critical applications. The new site is carrier-neutral, operating at a PUE rating of below 1.3 and powered by resilient, 100% dual diverse renewable energy feeds.


Aqua delivered a highly energy-efficient, bespoke, closed-loop air cooling system with integrated free cooling. The design for Custodian’s DA2 includes 12 custom-designed cooling coils and a free cooling chilled water system, comprising of 3 x 500kW Aqua EcoPro+ optimised free cooling chiller units, to accommodate for the initial phase of the site opening. The EcoPro+ units operate on R454B green refrigerant. Utilising integrated free cooling chillers, drastically reduces the amount of time mechanical cooling is required, saving significantly on energy usage, carbon impact and wear & tear of components parts, in particular the compressor.

The Aqua EcoPro+ units have an in-built, optimised, free cooling coil, resulting in a fully packaged solution. In addition, with an Aqua unit, free cooling is achievable at higher ambient temperatures than with any other brand on the market, making Aqua a suitable partner for Custodian and its ever-growing client base as it allows for upgrades and additional capacity quickly and easily as needed, depending on customer needs.

The system installed at Custodian achieves all the benefits of a fresh air system but without the need for the costs and resources normally associated with air filtration and maintenance. Fixed humidity control enables precise temperature control, eliminates any guesswork, and achieves total peace of mind. EC fans installed on-site maximise system efficiency even further, as well as achieving stable pressure control.

With the new DA2 Dartford site boasting a 10MW capacity, we needed a reliable cooling system that could handle the increased demands from the bigger site. Aqua’s bespoke energy-efficient systems and esteemed trusted experts means our customer’s data remains protected and running at optimized efficiency”, says Callum Woodhouse, M&E Manager at Custodian Data Centres. “Their sustainability commitments align with our overall company goals in reducing our carbon footprint, whilst providing a cost-effective and reliable solution for our customers. As our customer base continues to grow and expand over time, this Aqua solution allows us to adapt to the additional demands, in a seamless and efficient way”.

A fully concurrent maintained pipework system is integral to the design, ensuring no single point of failure, something which is essential in the data centre industry. In fact, a part of the pipework can be removed without affecting the normal facility operations. N+1 capability was built-in on the mechanical equipment, including fans, coils, and pumps, this gives the facility full redundancy, in the unlikely event that a fault should ever occur, DA2 can continue to operate whilst maintenance is undertaken.

Mike West, Contracts Director at Aqua, explained “Custodian’s commitment to energy efficiency is evident throughout their data centre facilities and it was critical that the DA2 site needed to mirror the energy efficiencies achieved at Maidstone. Reducing carbon footprint for end-user clients – with lower operating costs – were key drivers in this project. Maidstone uses five times less energy per kW of IT load than an average data centre – a challenge we were more than happy to accept and believe we have exceeded!


Based on 500kW of cooling, the system is expected to use 106,766kwhrs/year. In comparison, a traditional chiller system would utilise in the region of 1,095,000kwhrs – resulting in a saving of over 90%. The system is also future-proofed, with the option for expansion into higher density cooling further down the line, as Custodian continues to grow and expand.

Find out more about the project here: