Google just announced its company wide carbon footprint and energy consumption on its green blog. The blog breaks down its sustainability report into 7 sections, one of which is data centers. While they didn’t confirm their DC energy usage as estimated in Koomey’s recent report, they do say that their DC energy usage is 50% less than most other data centers. There are a number of interesting videos on the blog that explain the steps that Google takes to reduce its DC energy consumption. I have included one here on airflow management that I would like to comment on.
Cold or hot aisle containment is a great way to improve airflow management (reducing the mixing of hot and cold air) in a data center, as Google proves in its video. However, this containment does not affect the airflow beneath the floor, nor how individual cooling units affect rack inlet temperatures. Google suggests that a computational fluid dynamics (CFD) analysis is a great way to understand airflow, but it is a one time analysis. It is also a lengthy and expensive process. Even a small change such as shifting IT load or removing/adding CRAC units changes the DC airflow making the CFD analysis useless. I always applaud Google for their dazzling animations and the simplicity in which they can explain things, but airflow through a data center is not as simple as they make it out to be.