Environmental Engineering Reference
In-Depth Information
6.3.2.8.3 Computers
New Energy Star 4.0 specifications for computers became effective on 20 July
2007. They require the use of 80 PLUS bronze level or higher power supplies.
Energy Star 5.0 became effective on 1 July 2009.
6.3.2.8.4 Servers
The EPA released Version 1.0 of the Computer Server specifications on
15 May 2009. It covers stand-alone servers with one to four processor sockets.
A second tier to the specification covering servers with more than four
processor sockets, as well as blade servers and fault-tolerant machines was
revised in 2011.
6.3.2.8.5 Appliances
Recently, average refrigerators need 20% savings over the minimum stan-
dard. Dishwashers need at least 41% savings. Most appliances as well as
heating and cooling systems have a yellow energy guide label showing
the annual cost of operation compared to other models. This label is cre-
ated through the DOE and often shows if an appliance is Energy Star [7].
Although an Energy Star label indicates that the appliance is more energy
efficient than the minimum guidelines, purchasing an Energy Star
labelled product does not always mean you are getting the most energy-
efficient option available. For example, dehumidifiers that are rated under
25 US pints (12 L) per day of water extraction receive an Energy Star rat-
ing if they have an energy factor of 1.2 (higher is better), while those rated
25 US pints (12 L) to 35 US pints (17 L) per day receive an Energy Star rat-
ing for an energy factor of 1.4 or higher. Thus a higher capacity but non-
Energy Star rated dehumidifier may be a more energy-efficient alternative
than an Energy Star rated but lower capacity model [8]. The Energy Star
programme's savings calculator has also been criticised for unrealistic
assumptions in its model that tend to magnify savings benefits to the aver-
age consumer [9].
Another factor yet to be considered by the EPA and DOE is the over-
all effect of energy-saving requirements on the durability and expected
service life of a mass market appliance built to a consumer-level cost
standard. For example, a refrigerator may be made more efficient by the
use of more insulative spacing and a smaller capacity compressor using
electronics to control operation and temperature. However, this may come
at the cost of reduced interior storage (or increased exterior mass) or a
reduced service life due to compressor and/or electronic failures. In par-
ticular, electronic controls used on new generation appliances are subject
to damage from shock, vibration, moisture, or power spikes on the electri-
cal circuit to which they are attached. Critics have pointed out that even
if a new appliance is energy efficient, any consumer appliance that does
not provide customer satisfaction or that must be replaced twice as often
