Conserving energy in an automated home - Part 1

In the same way that the saying “you’ve got to spend money to make money” works, sometimes it’s also necessary to spend energy to save energy. An automated home may have more gadgetry than normal homes, but if set up correctly these little power-consumers can help to save energy. While the debate about whether the apparent global warming trend is the result of our actions, it can’t hurt to try to reduce energy use (or rather, conversion) as much as possible.

For years computers have had the ability to reduce their power use by shutting down hard drives or going to sleep automatically. Since then advancements have been made to further reduce power use. Some motherboards and processors support reducing the speed of the CPU when it’s not in high demand, and some motherboards even let the entire computer go into a low power ’semi-conscious’ state suitable if you’ve got something that needs downloading. So if you combine all these features, you can save a good deal of power even for computers that must stay on most of the time (e.g. media centres, servers, home automation control systems).

Another way to improve the efficiency of a machine is to use solid-state memory. Generally this technology emits less heat than a hard drive, consumes much less power and operates much faster. The downside is the expense, the current relatively limited capacity, and their failure time (limited by number of write operations) for those that are based on Flash memory. However they are still suitable as system drives. Normally system drives never get the chance to go to sleep because they are needed for operations at the kernel level, and if you have virtual memory enabled they are also by default used as swap disks. SSDs don’t need to go to sleep because they only consume power when being written to and read from.

For systems that shouldn’t be on all the time the easiest thing is to make them go to sleep. The amount of power needed to keep a computer in sleep mode is significantly less than almost any other power saving mode. A small amount of current is used to maintain the system state in RAM. The best mode of all is hibernation because then the machine’s state is completely saved to hard drive so that the computer can be completely unplugged. I believe that Windows Vista uses a hybrid hibernation-sleep mode, which saves the state to disk before putting the computer into a normal sleep state (corrections welcome).

Embedded devices use relatively tiny amounts of power, so things such as the Media MVP should be preferred over their more power-hungry counterparts - in this case a media centre PC - where appropriate. Several companies are starting to produce really tiny PCs, based on embedded/solid state technology. These function like normal PCs, albeit at a slower speed, so can run standard PC operating systems, but at a fraction of the power. Some are even so light-weight that they can run solely off of a single roll-up solar panel. Since these are still quite new to the market, their price is relatively high compared to standard desktops, but prices will drop as demand increases. As a side benefit, since embedded systems are generally quite small, they use less resources and therefore I suspect they take much less energy to be produced.