Home networks and UPS
Energy Efficient Home Networks?
Historically (6-7 years ago?), consumers buying their second home PC would often transform the old one into a home server, using a hub or a peer-to-peer link to have printer sharing and (often internal) modem sharing over the home network. It worked, but obviously the system became more complex. Power management did not seem a friend of this configuration and many of these old servers were kept wide-awake. Also, after a few server-crashes due to micro-blackouts, a power back up in the form of a UPS came into play. With the entrance of broadband at the end of the 1990's an external ADSL modem was linked to the old PC. New PCs were bought, old PCs moved to children's bedrooms. Wiring the house became a nuisance, but a solution was found: A wireless LAN host in the hub plus a client side WLAN PCI-card in the old PC. And it still works.
The cost is considerable: Every network component with an external power supply (modem/hub or router/WLAN host) uses around 40 kWh/year. A UPS (Uninterruptible Power Supply) could use up to 25 W continuously (220 kWh/year). The old server, never actively operated by users but rarely switched off, could use at least as much (depending on type, power management, etc.). All in all, the home network -not counting the PCs and monitors could use as much as 600 kWh per year or more.
Quite simple: Bring the old PC, modem, hub and WiFi-host to the recycling plant, buy a low-cost (€ 200 - 300) combined ADSL Modem & Firewall/Router/PrinterServer/WiFi-Host, using only 40 kWh/year. Payback-times are within 2 or 3 years. Already that solution is robust enough to survive a blackout without spending half a day to get your network going again.
You could use the UPS for a client side PC desktop, but if data loss is that critical (e.g. in a home office) you really should be thinking of taking a notebook as your next home computer, because that comes with its own UPS (battery) incorporated and is far more efficient.
For real energy-efficiency fans
Try a peer-to-peer home network (no hub) of 2 highly efficient ENERGY STAR laptops, link one to a USB ADSL modem (no external power supply, using only a fraction of that 40 kWh!) and use an ENERGY STAR printer or MFD (also hooked up to a laptop) with good power management. And you'd probably keep total consumption of all your home computing under 130 kWh (€ 10)/year.
|The 1300 kWh Home office/Network|
|The 130 kWh Home Office/Network|
The following data are based on the rated Thermal Heat Dissipation of typical models:
Single PC Back Up (650VA, 400W max.) : 8 W (70 kWh/year)
Small Home/Office Server (1000VA, 600W max.): 25 W (220 kWh/year)
See also technical UPS page for definition.