The cooling of server rooms is not just complicated, it is also very expensive

The cooling of server rooms is not just complicated, it is also very expensive. Climateq took a good look at how to cool your server room AND reduce your energy costs

System downtime – two words that spell night terrors for every IT Manager. No matter whether they’re in charge of onsite data centres or small server rooms, they just know that ambient and temperature control is absolutely vital to prevent any disasters from happening.

Let’s take a look at a server room. It is usually packed with computers and servers that generate a lot of heat energy in a confined space. Ideally, server rooms should be located away from outside walls, without windows and well insulated. This is essential even though servers are equipped with cooling fans to draw air from one side and exhaust it through rear panel grills. Without ventilation, the build-up of heat can lead to equipment failure and even fire.

A modern server rack would draw roughly 15kW or more, and despite technologies becoming much more efficient, there are still around 2,500 BTU/hr (750 joules/second, or 0.75kW) of heat to deal with. Per rack.

The majority of server rooms should have a temperature of somewhere between 20 and 25°C – but I have surveyed server rooms that were maintained at 15°C and even less! Clearly a sign of little faith in the cooling equipment when you see the IT Crowd putting on a wooly hat and a puffer jacket before going to work.

Jokes aside, most equipment today will work at much higher temperatures of above 30°C. Even less worry if the UPS (uninterruptable power supply) batteries that emit heat, too, are stored in a different plant room. The guiding star for all things HVAC, ASHRAE (American Society of Heating, Refrigerating and Air Conditioning Engineers) is a big advocate of higher temperatures in server rooms to drive the cost of energy & equipment down.

We investigated and found some very interesting points that will save money and ensure that equipment, data, and personnel are kept safe & sound. This is providing that protocol is followed and the computer room air conditioners (CRAC) are installed in such a manner that they create a ‘cold-aisle’ for the front of the server racks and allowing hot air to be expelled from the rear of the cabinets into a ‘hot-aisle’.

  1. Server cabinet efficiency: A typical server rack can see a temperature differential of 20% between the top and bottom of a rack. Heat rises, so the highest temperatures will always be found at the top of the cabinet. To avoid hot air from being ‘trapped’, blanking panels should be used to prevent cold air from ‘escaping’ through the front of the unit.
  1. Monitoring ambient temperature: No matter if large or small, every facility should have a remote “ambient & environmental monitoring and alarm system” installed. The best of these systems are IP-enabled so that measurements and alarms can be generated and sent via the IT-network.
  1. Additional and redundant cooling: Air conditioners have to be regularly checked for leaks and other potential issues. This could mean a complete IT power down when the ‘aircon guy’ shows up. It’s either that, or having additional cooling in the form of, e.g., portable air conditioners, which can be rented rather than bought.
  1. AC maintenance: In our previous post, we mentioned the legal obligation to have your aircon inspected regularly. Aside from the TM44, you also require an Fgas report/certificate, and frequent AC engineer visits may cause disruption, especially if they find a technical issue that needs to be addressed immediately.
  1. Making the IT facility secure: Server rooms and closets are often planned and designed to leave extra space in case of growing data requirements. I have been in server rooms that were also used as storage spaces for all sorts of clutter. Here are the reasons why you shouldn’t do that:
      • If there are non-IT related items stored, you need to give access to unauthorised personnel. This would come with its own dangers.
      • One server room I inspected was packed with empty boxes from floor to ceiling. This blocked any form of airflow needed to keep the server equipment cool in the most effective way. Another had computer screens with access to the building’s security cameras. The heat emitted from that added to the cooling requirement.
  1. Growth factor: Be ready for the unexpected at all times. Your business might grow so you’ll need the extra space, your IT department may leapfrog into more compact virtualisation, or you’ll migrate your data to the Cloud. When planning your server room, leave room for all eventualities.
  1. Energy efficiency: Technology evolves at a rapid rate but it’s not just the server equipment that needs to be monitored in terms of age and efficiency. Lighting can generate copious amounts of heat you could certainly do without – only 10% of the energy consumed by a halogen bulb is converted into light. The rest 90% is turned into heat. So why not look into having LEDs instead? Another tip that I read is that exchanging your AC is a good way to save money. However, a halogen bulb is a lot cheaper to replace than a 10-kilowatt air conditioning unit. And this is where our expertise comes in. We are offering a retrofit technology that will reduce the energy usage of your existing ACs by 20% on average. COOLNOMIX AC-01 monitors the refrigerant in your AC unit, turning the compressor off once the ideal temperature is reached. The evaporator remains operational, allowing the residual refrigerant to continue to deliver cold air and maintain the room temperature. Once the refrigerant has reached its maximum cooling capability, the compressor is switched back on resulting in an average 20% energy (and carbon) reduction.

Now, I can hear the IT Manager shouting in the background – what if COOLNOMIX fails? In the very unlikely event of equipment failure, COOLNOMIX contains a failsafe relay which reverts to Normally Closed giving full control back to the air conditioner. The temperature setting in the wall control ensures that the temperature is kept to the correct operating level. As an added layer of security, should the air conditioner itself fail, the Coolnomix will emit an audible warning. No modifications are made to the AC unit, so all warranties are protected. And COOLNOMIX doesn’t just work a treat in server rooms, but any other room where the temperatures need to remain constant for prolonged periods of time, plant rooms, for example.

We certainly don’t know everything about servers, but when it comes to reducing your cooling bill, we’re the ones to talk to. For any cooling control requirements, server rooms or otherwise, contact our team on 01202 201480, or

Gérard Guminski


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