The Energy Wiz: Something New -- Distributed Thermal Storage
Designed to serve the small commercial and residential markets (where split A/C systems are common), the Ice Bear connects directly to a compressor's refrigerant lines, allowing it to freeze water sealed inside the Ice Bear unit, which holds about 50 ton-hrs (sufficient to carry a 7.5-ton load through a normal workday without running the system's compressor). Using a small built-in refrigerant pump, the Ice Bear circulates refrigerant through its sealed ice block, returning liquid refrigerant for use in the A/C system. No changes in A/C settings or operation are necessary, so occupants are unaware of the difference.
Where This Makes SenseWherever peak demand charges are high (e.g., over $10/kW month during the cooling season) and time-of-use or real-time rates apply (wherein daytime $/kWh rates are much higher than at other times), shifting chiller demand to off-peak periods will save money. Where retail electricity has been deregulated, flattening one's hourly load profile may also elicit a lower rate for power. On the other hand, where rates are flat (e.g., in some rural states or under a fixed price power contract) such shifting will not produce significant savings.
Depending on night climate, energy efficiency may also be improved since running the A/C unit's compressor when outside air is cooler (and no solar load exists) may allow it to produce cooling using fewer kWh. Standby losses are quite low: Ice Energy claims less than 1%/day, even on the hottest days. Power draw by an Ice Bear is minimal: a combined 300W for the refrigerant and water pumps.
At the wholesale power price level, any reduction of the system-wide summer peak will likely cut the hourly market clearing price (MCP), thus minimizing the overall cost to supply power. In some states, efforts to cut peak demand are rewarded through programs supported by utilities, state agencies, and/or grid operators. New energy codes may also encourage thermal storage. Municipal utilities in southern California are already embracing the Ice Bear, recently purchasing 10 units to test the technology.