Data Centre Cooling - Renew or Perhaps Upgrade?
Earlier data centres are approaching an age where their capital plant will be approaching its life point.
Decent mechanical equipment should last at least 15-20 years, but sadly the past couple of decades has seen capital cost prioritised over longevity, so much equipment will be found wanting at just ~10 years old.
Chiller equipment providing vital cooling for data servers is typical of this shortsightedness - short term savings creating long term headaches.
Although the data industry works to develop more efficient electronics that can function safely at higher temperatures, it has much earlier equipment heavily reliant upon mechanical cooling. Some cooling technologies have provided good energy efficiency, but what about longevity?
Cooling Plant Efficiency Improvements Since 2000
Major efficiency improvements have been achieved over the past 20 years, and with the advent of reliable Inverters over the past ten years along with reliable modes of control, the efficiency ratio of the typical air cooled chiller has steadily increased from ~2.5 in 1999 to >5 today. But what many users don’t realise is that retrofit techniques can achieve today’s efficiency from that 1999 chiller.
Retrofit is not just about fixing aged and unreliable components, instead it offers an entirely fresh approach, applying current techniques literally top down to older chillers.
A typical retrofit to achieve ESEER equivalent >5 will likely comprise…
- Inverter driven screw compressors
- High efficiency condensers suitable for a damp cold and salty climate
- Modern electronics with electronic refrigeration control
- Energy efficient EC Fans
- Improved part load efficiency, not just peak efficiency
- Continuous optimisation
External Remote Support
A Chiller retrofit applies the Data industry’s own technologies to facilitate remote support of chillers supporting data centres. For example the RODEM® system pioneered by ThermOzone offers two way interactive support whereby the chiller can be ‘Virtually Serviced’ entirely by remote access via mobile phone networks. The two way enabled system means the chiller can literally call for assistance if a fault arises, technicians can then log in to the chiller to investigate and invariably resolve what is going on. For most Clients assigning RODEM® support a monthly ‘Virtual Service’ inspection provides an early warning of any developing problems.
Efficiency Optimisation via RODEM®
Reviewing the chillers monthly provides opportunity to fine tune individual chillers to provide best efficiency for the specific season. Often chiller settings are set to provide year around functionality, for which a compromise is lower efficiency. By tuning a Chiller differently for summertime operation to that required in deep Winter means the chiller can be kept several % more efficient.
Unlike typical Building Management Systems that are inherently linked to internal data systems, RODEM using the 4G system stands completely alone, meaning external access does not in anyway compromise site data security. Remote access nodes are hated by data professionals, but no one objects to someone having a mobile phone in their pocket. RODEM® simply assigns a mobile connection to several chillers without need for any form of computer level link to the vital data systems, and hence no remote access nodes.
Global Warming and the F Gas Phase Down
Over 99% of data cooling chillers will be using a grade of refrigerant known as an HFC or ‘Hydro Fluoro Carbon’, of which R407C, R410A and R134a will likely dominate. Presently all of these ‘Fluorinated’ refrigerants are undergoing a major phase down under current EU legislation that will by 2030 see an 80% reduction in volume as measured by their GWP equivalent CO2 tonnage. 2018 has seen the level based upon usage in 2008-11 reduce to 54% and already the cooling industry as a whole is feeling the squeeze on HFC resources. However, older equipment on R407C and R134a can be successfully retrofitted to use low GWP alternatives, and coupled with significant energy improvements many retrofit projects achieve partial payback within 3 years (as measured by energy benefit alone) and invariably complete payback within 5 years.
Those still specifying new R410A equipment for any installation need to get onboard with F Gas phase down now. R410A systems cannot safely be retrofitted without major loss of capacity. there are simply no low GWP alternatives for R410A! It is reported R410A will meet critical supply shortages this year.
So as Data Centre cooling support equipment nears its life point there is an option to undertake a less radical upgrade rather than simply procuring more new chillers. Retrofit provides cost effective, efficient, long life, reliable solutions and invariably are less disturbing because original support systems, such as hefty chilled water pipes and mains supply cables do not have to be changed.
Retrofit is also a recognised form of recycling by re-use, is recognised by the Carbon Trust and significantly reduces the import of overseas manufactured equipment.
Certainly the attractiveness of new equipment has seen a major uplift in apparent machine quality when measured by its appearance, but all too often the aesthetics are literally skin deep, covering often a travesty of ‘value’ engineering. But hey ho who says retrofit cannot be applied after 5 or 6 years, indeed retrofit repairs to cooling plant <10 years old is a mainstay of retrofit business.