The top priority for Everest Data Centres is high energy efficiency. They appointed GalxC to provide them with a chilled water cooling system able to cope with high water temperatures, whilst providing very low energy use.
A privately owned operation, based in the south east, Everest provide high quality data centres supported by a 2N infrastructure. These Tier 3-4 aligned centre’s serve SME’s needing rack space through to companies who require data halls. With over 30 years’ experience of designing, operating and managing data centres they know what they are looking for when it comes to cooling.
With 12 years in the business Everest’s Managing director Ed Butler has seen huge changes within the industry. “Not only has the volume of data transferred over networks grown exponentially year on year, it’s what people use it for: 10 years ago people just wanted a website and email, now they have a wide variety of services running on many different devices.”
When it comes to cooling Ed has seen similar swings: “With the rise of energy costs there has been a big drive over the last few years for people to be more efficient. Data centre efficiency is typically delivered through the mechanical system, (cooling) as that is the place where you can achieve the greatest benefits from good design and efficient components.”
“We’re very pleased to have achieved that number,” Ed said, “it’s a considerable saving. Our clients want a building that is efficient but don’t want us to take any shortcuts.”
At GalxC we carry out many different projects including a wide variety of chilled water installations from data centres to manufacturing processes. For director Iain Hazell the biggest difference with this particular project were the high water temperatures.
“A lot of data centre enquiries we get asked for a water/glycol supply of 7°C and return at 12°C, or more recently in at 9°C and returning at 14°C, but Everest required a high percentage of free cooling which meant elevated water temperatures. We had to manage that increased range on chillers that are not designed to operate with such high return water temperatures.”
The solution was to create a bespoke system using standard plant, making sure there was complete control over the system, such as adiabatic coolers which were given separate controls for the adiabatic function and for when the chillers operated.
By running at a higher water temperature there is more capital expenditure, as you need more cooling surface area inside and outside the centre, but the flipside is increased efficiency.
As you can imagine Ed is delighted that Everest have achieved their PUE ambitions and is full of praise for the GalxC design: “It is well thought out and pragmatic. It is achieving the task and there’s an elegance to the engineering which we really appreciate.”
"Working with GalxC has gone very well, the guys in the team put together a good design and from supplying the equipment to the pipework installation that all went very smoothly and completed on budget and schedule."
How the system works:
Stage 1: It is all about ambient temperature
The major efficiency comes from the dry coolers being able to reduce the water temperature in the ring mains through the ambient air conditions. The system is just running fans and pumps and as long as the air temperature stays at or below 17°C no extra energy is required.
When the air temperature rises above 17°C Air Cooled Water Chillers are used to cool the water but, with UK mean temperatures hovering around 11°C, the chillers are rarely used for a large percentage of the year making a very good saving in energy costs.
Stage 2: Introducing the chillers
When the ambient temperature exceeds 17°C the chillers begin to operate.
The chillers have stepped capacity by virtue of having four compressors and separate circuits. Only the number of compressors required for the load are started, and the controls work in harmony with EC fans on the chillers to maximise energy efficiency.
The GalxC System in a nutshell
Up to 17°C ambient the system uses no refrigeration, and 100% of the cooling duty is from free cooling.
Optionally this 17°C can be increased to approximately 25°C by the use of adiabatic assistance on the dry coolers. (The exact point depends on humidity.)
The final tranche of cooling to cope with temperature extremes in hot summers is provided by chillers. This is to cope with the data centre requirement of 24x7x365 operation.
How the air is cooled at the data centre
The stainless steel pipework at the back of the building brings the chilled water to the CRAC (computer room air conditioners.).
Each CRAC has a cooling water/glycol coil. As the hot air is drawn into the units (below), it passes over the chilled water and the air is reduced to 21°C supply temperature.
This air is then fed back into the data centre so that it passes through the racks, extracting the heat generated by the computers and servers.
The cycle continues
The warm water comes back down the line at and depending on the ambient temperature the dry coolers and chillers will cool the water/glycol to be used again.
The Cooling System at Full Load
The data centre has capacity for four full rooms. The rejected heat load from the data racks in each hall is 750 KW. The four data halls will generate 3000 KW (3 MW)
The cooling system is made up of four parts, with each part being 1000kW (1MW). This total of 4 MW gives the cooling system a redundancy of N+1. If one part of the system encounters a failure then the other three parts (3 MW) are enough to cover the demands of the data centre as each circuit is split across all four data halls.
Energy savings are considerable and this is due to the large area available to install the dry coolers and also the average ambient temperature of the UK being 11°C or below for 9 to 10 months of the year allowing the system to just run on dry air cooling alone.
This project has been a great success. Not only is the client saving money and providing a very efficient service but GalxC have also proved their abilities for creative design with large scale cooling.
Our team of experienced engineers are standing by waiting to help our many customers with their cooling project requirements. Please do contact us by phone or email and we’d be more than happy to provide any advice or help. We look forward to hearing from you.