Cooling Can be CheaperCooling Can be Cheaper

Reducing the heat produced lowers the energy bill.

Did you know that about 45% of the energy bill for ICT systems is spent on cooling the equipment? Reducing the heat produced lowers the energy bill.

This became clear in the U.S. Department of Energy (DOE) article, "Database Technology Company Saves $262,000 Annually". The article recounts how Sybase decided to optimize their data center cooling and free up cooling capacity. Working with their local utility, Pacific Gas and Electric (PG&E), Sybase was able to save 2.3 million Kwh, reducing the energy bill by $262,000 a year. The project qualified for three rebates totaling $130,000. The payback for this project is 2.2 years. The Sybase energy managers were driven by:

* Increased growth
* Desire to avoid infrastructure investments
* Reduce cooling system failure risk
* Improve the data center efficiency
* Reduce the mechanical system stress

Sybase has two monitoring systems, one for building automation and a second for the data center. The article states that "continuous monitoring and measurement are a key component to operational success, including verifying ongoing system modifications. The data [collected] is used to discover information technology (IT) and facilities inefficiencies, quantify savings opportunities, justify budgets and measure savings."

Sybase accomplished the increased efficiencies and energy reduction by:

* Installing a high efficiency chiller and cooling tower
* Implementing controls that optimize the load on the chiller
* Increasing the server intake temperature(every 1 degree of higher temperature can save 4 to 5% in energy costs)
* Installing airside economizers that use cooler night time air to chill water in addition to the cooling tower
* Selecting better locations for the floor tiles, closing some tiles and adjusting the dampers. It is better to place a solid tile on the floor rather than closing an air adjustable tile. Closed adjustable tiles can waste 35 cubic feet per minute of cool air.
* Sealing any opening that would leak cool air such as conduits, equipment stands, ramp skirts and cable ways
* Installing Variable Frequency Drive (VFD) fans which allowed the control of air pressure feedback, thereby reducing the required fan power by 83%
* Installing air flow diverters on the discharge side of the racks to focus the high temperature air flow away from other equipment racks
* Eliminate unnecessary lighting with controls that turn off the lights after a 30 minute countdown

The DOE has two tools that are helpful for the enterprise in evaluating its cooling efficiency and energy consumption. The Air-Management Tool is intended for raised-floor cooling with hot/cold equipment aisles. Users will need to complete a data form and answer questions on four data input sheets:

* Air-handler unit data for calculating Return Temperature Index (RTI) (energy metric)
* IT-equipment data for calculating the RTI metric
* IT-equipment intake temperatures for calculating Rack Cooling Index (RCI) (equipment cooling metric)
* Input with questions for determining energy savings and recommendations

The Air-Management Tool will:

* Provide air-management recommendations
* Estimate the potential for reducing supply airflow rate and increasing supply air temperature (higher working temperature = lower energy bills)
* Estimate the percentage of energy reduction for fans and chillers

The DOE "DC Pro Profiling Tool" is a free downloadable software tool for identifying savings for ICT energy consumption. You input description information, utility bill data and system information such as:

* ICT data
* Cooling information
* Power consumption
* On-site power generation

The software then produces:

* An overall picture of the energy use and efficiency
* An end user breakdown
* Potential areas for energy efficiency improvement
* Overall energy use reduction potential

The DOE article has other resources for conducting data center energy assessment (pdf):

* Master List of Actions for DC Pro--this master list contains many of the energy efficiency actions addressed by the DC Pro Tool Suite that you can copy and paste into a data center assessment report

* Standard Report Template for Conducting a Data Center Energy Efficiency Assessment--this storable document provides a template for the data center assessment report, including the type of data that should be included.