Ice Storage systems save 95% of A/C Electric Costs
Whilst this is not new technology (Ice Thermal storage was first used in the UK in the mid 80’s in some large London Commercial offices through a series of Ice Storage tanks supplied by Calmac) it can be said that the application at that time was limited especially for smaller UK buildings. However that is now changing with technology now allowing it to be used in conjunction with packaged Rooftop A/C units and also at much smaller outputs. When applied correctly these systems save up to 95% of the A/C systems electric costs.
One such product – The Ice Bear system – which is a distributed energy storage solution that works in conjunction with refrigerant based commercial direct-expansion (DX) air-conditioning systems, in the 18-70 KW package rooftop systems common to many small to mid-sized commercial buildings.
The system – like all these Ice Thermal Storage systems works on a simple principle that generates and stores the cooling energy needed for the next day on the previous night, when electricity generation is cleaner, more efficient and less expensive, and delivers that energy during the peak cooling need of the following day to provide cooling to the building.
Daytime energy demand from the air conditioning equipment – which is usually around 40-50% of a building’s electricity use during peak daytime hours, can be reduced substantially by the Ice thermal storage system.
Each of these smaller systems delivers an average reduction of 12 kilowatts at the equivalent peak demand for a minimum of 6 hours per day, moving 72 kilowatt-hours of on-peak energy to off-peak hours.
How the system works
The system consists of a large thermal storage tank that attaches directly to a building’s existing roof top packaged air-conditioning system.
The unit(s) makes ice at night, and uses that melted ice during the day to efficiently deliver cooling directly to the building’s existing air conditioning system.
This type of energy storage unit works in two simple modes, Ice Building and Ice Melting, to store cooling energy at night, and to deliver that energy the following day.
During the Ice Building mode, a self-contained charging system freezes 450 gallons of water in the built-in insulated tank by pumping refrigerant through internal copper coils. The water around these coils freezes and turns to ice. Once the Ice- Charge is complete, the condensing unit switches off, and the ice is stored until its cooling energy is needed the next day.
As the daytime temperature increases, the air conditioners power consumption rises too. During this peak time, usually from noon to 6 pm, the Ice Thermal store unit replaces the compressor of the building’s air conditioning unit.
The thermal store, fully charged from the night before, switches to Ice Melting mode. The Ice Thermal store uses the ice, rather than the Air Conditioners unit’s compressor, to cool the hot refrigerant, slowing melting the ice as it passes through a series of copper coils. A small water pump pushes the ice-cold refrigerant through a modified evaporator coil installed in the conventional air conditioning unit.
The Ice Cooling cycle lasts for at least 6 hours. Once the ice has completely melted, the Ice Thermal store transfers the cooling back to the Air Conditioning unit, to provide cooling, as needed, until the next day. During the cool of the night, the Ice Building mode is activated and the whole cycle starts again.
You can find out more by watching the video
These Ice Thermal Energy storage systems are designed to store energy using lower cost off-peak electricity and deliver cooling on-peak, while consuming less overall energy in the building. When the unit is storing energy, it’s working as an integrated highly-efficiency Air Conditioning condensing unit at night, when the temperatures are lower and thermal efficiency are much higher.
During the day, the opposite happens. When the Ice storage unit is discharging its stored energy, it offsets the operation of the energy-intensive commercial Air Conditioning condensing unit at times when temperatures are high and efficiency of the A/C unit is at its worst.
This means the difference in operating efficiencies between the Ice Bear condensing unit and the commercial unit more than compensates for any inherent inefficiencies in the storage/discharge cycle common to other types of energy storage. In fact, when you factor in age, size, and high operating duty cycles, the Ice Bear condensing unit is clearly more efficient than the commercial condensing unit it is displacing.
Bottom line: These Ice Thermal storage systems reduces the total energy consumption for most smaller buildings under virtually all operating conditions. Larger systems of course can still work in conjunction with traditional chillers/heat pumps.
Want to find out more? Call us on 0345 373 0302