PUE is an industry acronym for Power Usage efficiency. It is the number by which a data center's efficiency can be measured. The lower your PUE the more efficiently your data center is utilizing the power.
So why is it important to me?
The more efficiently the power is used the lower the energy consumed, thus resulting in cost savings and lowering your carbon footprint. Lower energy costs can also be attractive for co-located data centers if you're billing your clients for their energy consumed, earning you marketing brownie points as well.
So what is my PUE?
Calculating your PUE is relatively straight forward, once you have the data required. It is a simple ratio of the total energy consumed over the amount of energy consumed by IT equipment alone. The resulting figure will tell you the ratio of how much energy is being used to run ancillary services, such as lighting and cooling, etc against how much is used by your IT equipment. A perfect PUE of 1.0 (impossible (?) to achieve) would mean that 100% of the energy being consumed is for operating your IT equipment. This means you are probably working in the dark!
So to calculate your PUE you need to gather data on your energy consumption. An easy way to do this would be to look at your energy bill to know your total consumed. You will then need to install power meters in your cabinets to get an accurate reading of the power being used by your IT equipment. The measurements should be taken as close to the appliance as possible, as the further away you go higher the power consumption reading will be due to internal resistance in the cables.
Measure these numbers over a period of weeks or months. The more data you have the more accurate your PUE result will be. The important thing to remember is
1) If you can't measure it you can't calculate it.
2) Measure as often as you can.
AKCP provides a range of sensors, devices and software that you can use to help identify your power consumption and aid in calculating your PUE.
So now you know your PUE, what next? The aim would be to improve it. If your figure is already around the 1.4 mark, you are doing pretty good. If you're seeing numbers of 1.6 then there's some improvements you can make.
If you don't have it already, implement containment. Prevent your hot air from mixing with the cold air and ensure you have a positive airflow of cold air through the servers. If you do have containment already, make sure it's properly sealed. Check for gaps under your server cabinets and missing blanking panels. You can reduce your PUE simply by having a well designed and sealed data center. AKCP provides containment solutions for small to medium sized data centers. Chimneys will aid in removing the hot air from your cabinet and vent it to outside the room.
Another thing you can do is raise the temperature. Yes you heard it right, run your data center hotter. Many data centers run too cold, much lower than the recommendation from ASHRAE. By increasing your temperatures, you lower the demand on your cooling systems saving you money in the long run. AKCP can help you monitor the temperature in your data center. The Thermal map temperature sensors with the SP2+ device will make sure that you have an accurate picture of the temperature status in your cabinet and ensure that you are alerted should they become a critical status. You can also utilize this data to manage your cooling and maximize efficiencies.