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Ice Energy uses a standard 5 ton air conditioner condensing unit to make ice during the evening off-peak hours. Stored ice energy provides cooling during the day when the energy consuming compressor is turned off and replaced with a small 100 watt pump. The pump moves warm refrigerant through copper coils in the ice energy storage module. The cooled refrigerant then moves through standard evaporator coils to produce air conditioning. Ice Energy is invisible to the user because it acts and feels like an ordinary air conditioner. The system doesn’t require an expensive engineering or feasibility study and even uses existing thermostats and ducting. The terminology for our air conditioner is; 100% refrigerant based, direct ice-on-pipe, thermal energy storage with liquid overfeed. The unit has two modes of operation known as load shifting and load leveling. In the load shifting mode, stored ice energy provides 95-100% of the daytime cooling capacity reducing typical peak energy consumption from 5,000 to less than 100 watts. In the load leveling mode, the ice and condenser work together in a unique two step cooling process. Daytime peak demand is leveled by up to 70% and overall efficiency improves by up to 30% based on the cooling demand. Understanding Load-Shifting The ice-make condensing unit can accept real time pricing and compressor lock out signals from a smart meter, or run at a predetermined time to take advantage of utility rates. In a load shifting mode the ice-make condensing unit runs only during low price and off peak times. During high price and peak demand times, the Ice Energy storage module cools refrigerant and pumps air conditioning to the building through a standard evaporator coil. In other words, even with the compressor switched off or locked out by the utility, the Ice Energy air conditioner continues to provide up to 50 ton hours of uninterrupted cooling. Typically the ice-make condensing unit operates to recharge or build 50 ton-hours of cooling capacity ice at night, 7 pm until 7 am. In Figure 1, the ice storage module was fully recharged by 0430 hours. Off-peak compressor operation peaked at 4,960 watts. During the day the compressor is turned off and a small pump moves the refrigerant through the ice and evaporator coils. The graph shows the dramatic ice energy storage load-shifting capability. After installation the results are immediate, measurable and dramatic. Figure 1 Understanding Load-Leveling and the Revolutionary Two Step Cooling Process Ice Energy revolutionizes air conditioning by using a unique two step air conditioning process. The two cooling components in the air conditioning process are sensible (temperature reduction) and latent (moisture removal). The separation of the two cooling processes yields the greatest energy efficiency possible in a refrigerant heat transfer cooling process. In a load leveling configuration, we independently control space humidity and temperature, to reduce fan horsepower and decrease on-peak demand 30 to 60 percent with an EER24 efficiency rating of 15+. Depending somewhat on the geographic area, a small to medium sized commercial customer’s cooling load is composed of about 70% sensible and 30% percent latent. In the first step of the process, we use a thermostat to control a sensible-only condensing unit and evaporator coil, reducing temperature. In the second step, a dehumidistat controls the latent-only ice energy storage module and evaporator coil to remove moisture. Defining the Revolutionary Change When you install a 5 ton unitary air conditioner the evaporator coil is sized to deliver 5 tons of cooling in order to maintain the correct suction pressure and resultant refrigerant temperature. The single evaporator coil temperature is set to perform both latent and sensible cooling. The load-leveling Ice Energy air conditioning module uses the same 5 ton unitary air conditioner but the first stage evaporator coil is sized to deliver 7.5 tons of cooling at a suction pressure of 93 psig or 55F. The first stage evaporator coil performs about 70% of the work delivering sensible cooling at 20+ EER. The Ice Energy storage module is connected to a second stage evaporator coil and running at approximately 65 psig and 37F, pumps liquid refrigerant to deliver latent cooling. In a standard configuration the first stage compressor is controlled by a thermostat and the second stage pump is controlled by a dehumidistat. Yet another unique technique called liquid overfeed allows the 2nd stage evaporator coil to return both liquid and vapor refrigerant to the storage module. If the utility shuts off the 1st stage compressor due to an emergency load curtailment, the second stage picks up the work and the building receives uninterrupted air conditioning.
Specifications: Ice Energy Storage Module Cooling Capacity 50 ton-hours or 600,000 Btu’s Thermal Energy Medium Water Maximum Heat Transfer Rate 12.5 tons/hour Refrigerant 100% R22 Ice-Make Condensing Unit Factory stock 5 ton residential style Power Requirements 208/240 Volt, 60 amp, single phase
Standard Configurations: |
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