Energy Saving

Low Energy, Low Cost Solutions for Schools and Call Centres

One of the unfortunate effects of modern multi-core high performance PCs, is the rapidly increasing amount energy they consume. It is also true that the average PC spends up to 80% of its capacity and processing time in antivirus and other security related activities. This leads us to consider whether it is necessary for every office worker or school student to require such powerful machines to run comparatively small computer tasks.

Our brief for The Rosary Catholic Primary School, Birmingham, was to create an IT suite for 30 pupils with low energy use on a small budget. Following a study of the software in use, we installed a thin client solution using micro PCs mounted on standard multi media monitors. These where connected to a small entry level dual processor (8 cores) server running Microsoft Windows Server 2008 with Remote Desktop Services. Key to the solution was not in the server but in the use of free open source software to boot and run the 30 remote desktop connections. For this we chose a product called “Thinstation” available from www.thinstation.org. This has the advantage of not requiring a client operating system like Windows 7 or XP, as it contains the ability to boot from the network adapter or PXE from the server.

The result:

1          30 low energy client workstations using a fifth of the electricity of standard PCs.

2          Low cost of hardware

3          No cost in client operating systems

4          Low maintenance costs. Micro PCs running Thinstation require no hard drive, cooling fans and without operating system there’s little to infect or corrupt.

5          But the feature the teachers liked the most was the single switch on the wall. One touch and all the 30 machines turn on and are ready for use instantly.

Other Energy Saving Solutions for Work Groups

In locations where several PC users are working in close proximity, and particularly where their work entails light processor work as for example call centres, school classrooms, or office administration functions, consider using a shared PC. This is where up to 6 users, each with a separate screen, keyboard and mouse, can use the power of the modern PC in up to 6 separate sessions. This solution drastically reduces energy consumption by using one PC where 6 would have been. The solution called SoftExpand uses the WinLogon application within Microsoft XP to create up to 6 simultaneous user sessions each independent and without interference from other users.

Energy Saving Tips

Over the past 5 years machine average power requirements have almost doubled from 300w to 550w. Dual, Quad and 6 core processors with large RAM requirements, hard disc size and display sizes have increased almost exponentially to create the modern high performance but power hungry machine.

From a user’s perspective, tight controlled use of the operating system power saving tools is all important. Here, there are normally 4 elements which can be used to conserve power. These can be described in order of saving. A controlling factor in the use of these is the amount of time required to recover to full machine working:

1          Display brightness. Moderate the settings of the brightness and contrast setting to the minimum comfortable setting. Where available by the operation system, allow the screen to dim after a reasonably short period of time.

2          Screen Saver. Modern LCD or plasma monitors do not require screen saver, these was a requirement of Cathode Ray Tube heavy glass tube monitors. Using a screen saver has only a small effect on power consumption.

3          Display standby. Set the operating system power setting to go to monitor standby which will turn off the monitor back light. This is power efficient and quick to recover to a work machine. This should be done if the machine is left unattended for 5 minutes.

4          PC sleep modes. In most PC and laptop operating systems there are for levels of sleep. These are described as sleep states as:

S1 = Basic Standby (Shallow sleep). Typically wakes up in no more than two seconds 

S2 = Less power consumption than S1 and greater than in S3. Wake up is usually two seconds or slightly more.

S3 = Less power consumption than in S2. Wake up time is the same as S2.

These by degree reduce processor activity, store the RAM cache to hard drive, stop the hard drive from spinning and power down to hibernation.

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