Cooling the cloud: A look inside Google’s Hot Huts

10/23/12 | 1:45:00 PM

If you’ve taken a look at our new site, Where the Internet lives, you’ve gotten an in-depth look at some of our infrastructure and the people who help keep Google up and running for you. Our data center infrastructure is the foundation for all Google services, powering our servers, networking equipment and cooling systems.

Our emphasis on cooling systems might come as a surprise, until you consider how warm a personal computer can become during use. Data centers, which house thousands of computers, need to stay within a specific operating temperature range. Even though we run our facilities hotter than a typical data center, we need cooling systems - both to prevent server breakdowns and to provide a reasonable working environment for technicians working on the data center floor.

After servers, the second largest consumer of power in a data center is the cooling system. We needed a cooling system which minimized our overall energy consumption. For this reason, we designed our own cooling systems from the ground up.

This photo shows several of our custom cooling systems arranged in a row with racks of servers pushed against them on both sides. We named these units “Hot Huts” because they are sealed from the rest of the data center floor. Sealing away the hot air increases cooling efficiency.



The interior of a hot hut row

The black circles along the walls in the photograph above are the exhaust fans on our server trays, and the hoses coming up from the floor contain water going to and from the cooling coils in the top of each unit. Fans on top of each Hot Hut pull hot air across these water-filled cooling coils. This cooled air leaving the Hot Hut returns to the ambient air in the data center, and machines can draw in this air again to cool themselves down, completing the cooling cycle.



Set of active racks pushed up against hot huts


We chose a water-based cooling system for our data centers since water can hold more heat than air. Water-based cooling means running pipes under the raised floors in our data centers. With so much electrical equipment in place, we take precautions with regular inspections and an alarm system which detects leaks. Here, a data center technician inspects underfloor water pipes which lead to a heat exchanger in the cooling plant.

Inspecting underfloor pipes

By providing this view into our data center operations, we hope to inspire other companies to rethink their approaches to data center cooling. Building our own cooling systems means we can keep our data centers cool using a fraction of the energy used by a typical data center chiller, and that translates to reliable, carbon neutral services you can use for free.