As data centre cooling is responsible for the majority of ‘non compute’ energy consumption in the data centre, getting the right solution to ensure ultimate efficiency is the goal of most data centre professionals.
Fortunately, there are multiple energy efficient cooling systems available to satisfy most requirements all providing their own unique benefits, ultimately the choice will be made on a range of metrics, but the key deciding factor will be the level of energy efficiency
There are many explanations or descriptions for the term ‘Efficiency’ – ‘One of the best analogies for describing efficiency in data centres has to be ‘the good use of natural energy in a way that does not waste any’. In terms of data centre cooling systems available on the market today this terminology is probably best suited to describe Evaporative Cooling Systems.
Evaporative cooling is nature’s method to cool, it is the system your body uses to cool down and certainly the most sustainable, and environmentally friendly system by far.
So how does it work? Evaporative free air cooling technology makes use of the external air to cool the data centre environment, unlike simple air economisers which require supplemental or chilled water when external temperatures reach 210C, Evaporative systems engage the cooling mechanism by simply passing the airflow through wet filter pads.
So what is so good about it? The primary benefit is the drastically reduced power consumption in comparison to more traditional systems, in fact the well-known FreeCool® Evaporative data centre cooling system delivers typical power consumption reduction of 90% compared to some traditional mechanical systems, delivering typical PUE3 of 1.15 or lower. Other primary benefits include: -
- Reduced CO2 emissions
- Significantly reduced energy consumption and operating costs
- Supports existing cooling technologies
- Improved DCiE / PUE ** Efficiency Ratings
- Improved company “Green Credentials”
- Improved resilience with practical support by UPS systems
- Flexible airflow configuration options
- Modular, Scalable Architecture
- Can be deployed as a new scheme or retro-fitted to existing data centres
In practical terms, the benefits above not only allow for robust operational advantages but also provide sound commercial and financial benefits allowing users to take advantage of significantly reduced cost overheads, and where available take advantage of government grants that are available to support the installation of such systems.
Nothing is perfect so what are the drawbacks?
In the past Evaporative cooling solutions have been dismissed for server room and data centre environments due to historical issues with air quality and humidity control. Specialist Data Centre centric direct air Evaporative cooling systems such as Freecool® challenge the barriers to air economiser cooling as a suitable technology for server room and data centre environments.
The obstacles to air exchange have been removed as modern computing equipment is much more robust with regard to both temperature and humidity.
Typical computer manufacturer environmental operating specifications are 10ºC to 35ºC and 10% to 95% relative humidity. ASHRAE have acknowledged the advances of modern computers and the need to balance energy efficiency against system reliability. ASHRAE make recommendations for a server room temperature range of 18ºC to 27ºC, it is recommended that humidity levels are replaced with dew point.
Another observation on a sustainable note is the requirement of the system to use water during the cooling process, however not only is the use of water in evaporative systems around 25% less than traditional water-cooled chiller plant, the water that is used then simply evaporates into the air, so that nature can re-use.
It is of course true that poor air quality can cause detrimental issues where direct air is used, as designers of the direct air Freecool® system we have recognised this and have a two-fold solution, firstly all external and internal Freecool® systems are fitted with a combination of G3 / G4 filters.
The optional “Coolwall” system is designed to deliver instant backup in the event of a range of programmable conditions including external air quality, internal environmental conditions, fire suppression activation or primary cooling failure. The “Coolwall” consists of chilled water cooling coils which are designed to support full cooling capacity at 20ºC external ambient. The “Coolwall” installation is designed to restore 100% of cooling capacity within 30 seconds of activation and is controlled by the Schneider Crouzet controller which will ensure appropriate dampers are closed to support closed loop cooling.
So how about some real life examples of where this technology has been used?
Evaporative cooling technology is deployed throughout the data centre market from Telco operators, to colocation providers, standalone privately-owned data centres to the Public Sector. Two of the most outstanding examples include the multi award-winning Leicester City Council and University of Aberdeen data centres.
Both projects utilised Freecool®, probably the most well-known Data Centre Evaporative cooling system, the cooling was a significant element of the complete Design and Build Services provided by Workspace Technology Ltd.
University of Aberdeen
The NESS partnership (North East Shared Services) is a joint venture between the University of Aberdeen, Aberdeen College, Robert Gordon University and Banff and Buchan College. It was agreed to create a “Shared Services” data centre facility. The existing data centre located at the Edward Wright Building on the University of Aberdeen’s campus was the preferred location. This data centre was approximately 23 years old supporting the University’s core ICT services. This facility had enough space for the combined rack count but was out dated and lacked the required power, cooling capacity, defined installation standards, and suffered from a PUE of 2.6.
The innovative solution provided, included Design, Civil and Construction works, Freecool®, Technology, aisle containment, electrical design including Schneider switchgear, back-up power generation, structured cabling and Schneider APC rack and PDU’s, StruxureWare DCIM and post contract ongoing 24/7 support and maintenance back-up – all services were delivered by Workspace Technology’s highly experienced in-house teams.
An annualised PUE3 of less than 1.15 has been achieved. The financial benefit is a reduction in the power bill for the data centre by £94,000 per year whilst improving the environment by reducing the data centre carbon foot print by 612 tonnes per year. Across all the NESS partners the refurbished data centre will produce an annual financial saving of £256,000 with the total carbon foot print being reduced by 1450 tonnes.
This innovative data centre has been awarded multiple accreditations and awards including the prestigious British Computer Society – Data Centre Project of the Year, & Computer Weekly – Public Sector Data Centre of The Year 2013, and Green Gown – Effectiveness and Efficiency.
Leicester City Council.
Workspace Technology Ltd delivered ‘Carbon Neutral’ Cooling, as an integral element to a complete design and build project. The solution utilised the Freecool® Direct Evaporative Cooling System combined with contemporary renewable Photovoltaic (PV) Technology, with back up resilience provided by Workspace Technology’s Coolwall system. The PV power contribution exceeds that of the Freecool® power consumption.
Freecool® installations are designed and built from scalable standardised modules that can be interconnected in a bespoke arrangement supporting ‘real world’ client applications. The Leicester City Council project was no exception with the solution designed to support a maximum critical load of 250kW N+1 with a deployment of nine 30kW Freecool® units.
Workspace Technology provided another award-winning complete turnkey installation including full design of all construction, mechanical and electrical systems, completed by our own in-house construction, engineering and installation teams.
So, is Evaporative FreeCooling - The Big Daddy of Data Centre Cooling?
There are of course other cooling systems that provide some great innovations, and of course Evaporative Cooling is not a solution that will suit all applications or preferences. So, is Evaporative Cooling The Big Daddy of Data Centre Cooling? - maybe not, but it certainly can be described as The Greenest Cooling Daddy!