The Art & Science of Cooling


Rising energy costs, limits on resources and environmental regulations are a few of the challenges driving the need for energy-efficient, sustainable data centers. Building a data center requires a holistic approach to your entire infrastructure and not just your IT equipment.

Engineers of server systems often start with an assumption that they will have no static pressure difference from front to back. Servers take inlet air (supply air), use it to cool components and reject heat via outlet air (return air). The difference between supply and return temperature is referred to as ΔT and is a crucial design factor that affects all cooling systems.

Traditional cooling methods fight the airflow of servers; they overflow or underflow the air supply or over-speed the air velocity. Overflow of supply reduces ΔT, reducing the efficiency of all cooling processes. Underflow of supply air requires servers to do more work, resulting in higher internal temperatures and fans working harder to pull air that they should not have to pull. Over-speed refers to situations in which velocity of air from CRACs is too high for a cabinet in the path to receive cool air, resulting in higher, not lower, temperatures.

KyotoCooling changes many long-held preconceptions about cooling and represents the lowest risk option for a data center designer and owner.


To cool with air, you must control that air. Control means:

  • Delivering the right amount of air to cool with maximum efficiency, and
  • Cold air does not mix with hot exhaust air — recirculation or temperature contamination is responsible for inconsistent temperatures from the floor to top of the rack.

Typically, bypass and recirculation account for a 30 percent loss of efficiency in data center cooling. We separate and control cold and warm air, resolving the first risk of cooling— control of temperature across long aisle spaces from the floor to the top of rack. The impact of this control is immediate and sensible — there is consistency in temperature and certainty in airflow. We have proved through empirical data, computational fluid dynamics and laws of engineering why this works. Ask the hard questions … we have the answers.


We believe that it’s smart not to change the design conditions for optimal server performance. We precisely control the flow of air based on measured ΔT. We are able to maintain precise balance in pressure between the cold and hot spaces created by containment systems to deliver an optimal environment for server operating conditions. We deliver an exact volume of air at a precise temperature to the cabinet face, even under changing load conditions, all without operator intervention. We provide exact cooling for the intended load.


The patented design of KyotoCooling uses a specially designed energy recovery device, known as the KyotoWheel, for air-to-air heat transfer without bringing outside air into the data center. The KyotoWheel operates at extremely low rotational speed and has performed reliably in the industry for 25+ years under harsh operating conditions.

The KyotoCooling units are deployed in a redundant N+1 or N+2 design. This assures continuous operation during maintenance, service or failure of a unit. In N+1 or N+2 deployments, Uptime Institute Tier 3 and Tier 4 designs are achieved. The total KyotoCooling solution has been verified by external sources and long-term tests over a wide range of ambient and load conditions.


The system is designed to act and react as necessary to achieve continuously stable operating conditions. Load changes are automatically stabilized to target predetermined operating metrics. This means the addition of load can be accommodated within minutes — irrespective of data floor location — automatically and without risk or disruption. No site level programming is required- the system is self-tuning.

We are experts in controlling air and ΔT assessment, design and control. Mission-critical cooling starts with a solid understanding of the thermal environment on the data floor and how to control the air that supplies it.