Archive for the ‘Energy savings’ Category

A Low-Tech Solution to a High-Tech Problem

Tuesday, May 26th, 2009

According to the US Department of Energy, data centers consumed 1.5% of all electricity in the U.S. in 2006.  Additionally, the power usage by data centers is growing at the rate of 12% per year. (Scheihing, Paul. “DOE Data Center Energy Efficiency Program.” U.S. DOE Energy Efficiency and Renewable Energy. May 2008. U.S. Department of Energy. 26 May 2009)   This translates to a huge and very technical problem, which is getting a lot of attention given the emphasis on “green” initiatives by some of large companies that operate these data centers. Such a large problem in fact, that IBM CEO Samuel Palmisano predicted that 70% of the world’s largest companies “will modify their data centers significantly in the next five years” (Wall Street Journal, “Cutting Tech’s Energy Bill”, September 9, 2008.) Fortunately, the low-tech strip curtain is helping offer some relief to this problem.

 It seems like strip curtains or strip doors–the clear vinyl strips that you see hanging in the doorways of beer coolers and walk-in freezers–have been around forever.  They are often used as a “low-end” solution where a practical, reliable, economical thermal barrier is required.  So how are these low-tech workhorses providing relief to such a high-tech problem as data center energy consumption?

The answer lies in the redesign of data centers for improved “hot aisle/cold aisle” airflow management. In these redesigned configurations, cold air is brought up through a raised floor in the cold aisle (i.e., the front side of the server racks).  This cold air is then pulled through the servers from the front (cold aisle) side to the exhaust (hot aisle) side of the server.  This hot air is then pulled up to the return air ducts in the ceiling. Without a physical separation between the two aisles, the hot air can spill over the tops of the servers and intermingle with the cold air on the cold side of the racks — a big problem where energy efficient cooling is concerned.  (”High Performance Data Centers; A Design Guidelines Sourcebook.” High-Performance Buildings for High-Tech Industries. January 2006. Pacific Gas & Electric Company. 26 May 2009.)  This is where the strip curtain comes to the rescue.

The strip curtain is hung from the ceiling over the tops of the servers to serve as a physical separation between the cold aisle and the hot aisle, resulting in dramatic energy savings.  In fact, according to a presentation by James Hamilton of Amazon Web Services at the Google Google Efficient Data Centers Summit in April 2009, just controlling the airflow in the data center can result in a 12% improvement in power usage effectiveness (PUE).  (Hamilton, James. “Google Efficient Data Centers Summit; Data Canter Efficiency Best Practices .” Going Green at Google: Clean Energy Initiatives. 01 Apr 2009. Google, Inc.. 26 May 2009)

Not a bad contribution for a low tech solution like a vinyl strip curtain!

Note:  Chase Doors, the host of this blog, manufactures and sells door products including the vinyl strip curtains and strip doors mentioned in this article.  Additionally, it hosts a related e-commerce site www.stripdoorsonline.com.

Free Strip Doors?

Thursday, March 19th, 2009

There is no free lunch, so the saying goes, but there may be free strip doors.  Again for 2009, several California investor-owned utilities are offering rebate programs to motivate customers to install certain energy efficient equipment and fixtures.  Covered items include strip doors and swinging plastic doors.

Under the program, customers must first install new strip curtains or plastic swinging doors on doorways of walk-in cooler or freezer boxes or refrigerated warehouses.  They can then submit a rebate form to one of the participating utilities, which include Pacific Gas and Electric (PG&E) and Southern California Edison (SCE).  The utility then reimburses the customer $3.00 per square foot calculated on the size of the doorway.   Depending on the supplier and the type of door purchased, this rebate can cover the full cost of the door.  For example, searching a couple of online sources, I found an average price of $63 for a 3′x7′ strip door with 8 strips with 50% overlap.  The calculated rebate on the door–$63 (3 x 7 x $3).  (In this example, the customer would incur shipping costs, so technically, the door would not be completely free, but it’s pretty close.) 

The popularity of the rebate program, which was created by California’s energy regulators in 2005 in an effort to eliminate the need to build three new power plants, has created a problem.  The $2 billion funding for the program, which came from increased rates charged to the utilities’ customers, was intended to last through 2008, but the unexpected popularity of the program caused the funding to run out during 2008.  This left about 12,000 customers waiting weeks or even months for their rebates.  Fortunately additional funding for the program has been appropriated, and the 2008 and 2009 rebate checks are once again flowing. {Baker, David R. . “PG&E rebate program gets cash advance.” SFGate (San Francisco Chronicle) 14 Mar 2009 C - 1. 19 Mar 2009.}

If you are interested, the links to the PG&E and SCE rebate programs are as follows: (PGE ; SCE).  

Note:  Chase Doors, the host of this blog, manufactures and sells door products, including the strip doors and swinging plastic doors mentioned in this article.  Additionally, it hosts a related e-commerce site www.stripdoorsonline.com one of the sources from which pricing referred to herin was obtained.