Smart Fridges, Part 2  

Ars Technica has an article on a CSIRO design for creating networks of smart fridges that intelligently manage power consumption (you'd really need to make this part of an overall smart grid strategy though, rather than just allowing the fridges to do their own thing) - Refrigerators will use peer-to-peer power management.

An Australian research agency has developed a power-management approach for refrigerators in which the appliances talk to each other to determine the optimum time to use power from a mix of renewable and conventional sources. The system adds a peer-based network to the usual command-and-control structure in which a utility or firm hired by a utility remotely changes appliance behavior or sends a request to a customer's equipment for a change in behavior.

Refrigerators and freezers have a surprising amount of discretion about some activities they perform, with a range of safe temperatures, and certain activities (primarily defrosting) that can happen at any given time. With no internal clock and no knowledge of power-grid events, refrigerators may choose to use the most power at the worst time.

The design from CSIRO, Australia's national science and research agency, would allow a large network of refrigerators to coordinate usage among each other: if one refrigerator was reaching the end of a safe abeyence in lowering temperature, and another could put off a defrost cycle, they could negotiate behavior.

Similarly, CSIRO envisions fridges that have the ability to store power in the form of using excess solar power during non-peak times to reduce internal temperature. By reducing temperature ahead of times, power use is offset. In a similar manner today, some office buildings can build ice at night using cheap, off-peak power that's used for air-conditioning during the day. (While there are many arguments about the subject, solar-power systems in some areas—including parts of Spain—are generating surpluses during lower-demand daylight hours at times of the year.)

In a 2001 report, the latest available, the US Department of Energy estimated that a refrigerator and freezer consume about 16 percent of American households' power, about the same as all lighting and home electronics combined.