Ice Bank or Cooling Energy System
Many cooling installations only operate for limited hours during the day, and in the limited hours, the amount of consuming cooling energy is very high.
In this case, we can name the huge milk pasteurization industries and factories of producing soda and factories of producing drug raw materials.
Is it necessary to install a large refrigeration system that doesn’t operate during the day and only works for limited hours?
After all, electricity tariffs are higher at day than at night, so what to do?
The most glaring answer to these questions is the cooling energy storage units, or “Ice Bank“, which allows us to have a smaller and much less expensive refrigeration system by saving energy and cooling capacity during the closing hours of installations that electricity tariff is less.
This high score causes Ice Banking consuming to be constantly expanded and constantly found new applications.
In some countries, these units are used as an essential element of air conditioning installations. The cheap cooling energy produced at night in the middle of the day when the weather is warm is pumped to the fan coil or air conditioner of the buildings.
Ice Bank Manufacturing Bam Tabrid Sazan Co. is built according to the amount and capacity required and the type of application of designing:
Each kilogram of ice has a latent heat of melting equal to 334 KJ.
Each meter of coil tube of the Ice Bank can store up to 6 kg of ice in the water tank at night. That is, the cooling energy equivalent to 2000 kJ per meter or kilojoule (two million kJ per thousand meters).
The cost of electricity for the production of the above ice is less than the cost of producing it during day hours because the tariff for overnight electricity consumption is lower.
There is zero degree water between the coil tubes which have 30 mm ice, which is pumped to the heat load and returns at approximate temperature and melts the stored ice until the ice to be finished.
During the working hours of the system when the ice melts, the coil of Ice Bank can continue to produce cold.
Ice Bank causes the cooling system (compressor, condenser, etc.) to be smaller and electricity cost to be less.
Ice Bank is widely used in milk pasteurization, soda and air conditioning industries.
This device is used to produce cold water by freezing as forming ice on cooling plates.
This device can store significant amounts of refrigerant energy as the ice and use it at peak load times. By this method by a smaller compressor, it can provide refrigerant load.
The specifications and privileges of this company’s ice banks are as follows
– Outlet cold water temperature up to 0.5 degrees Celsius
– Keeping water temperature constant during use
– Excellent energy transfer due to the high turbulence of water
– Safe work due to lack of moving parts in the system
– Minimum space required to install the device
– Minimum amount of refrigerant charge in the system
– All parts in contact with water are made of stainless steel or PVC and therefore they have a very long life.
– The Ice Bank is seamlessly transportable.
– Working with a variety of refrigerants, including ammonia or freon refrigerants.
– Using with the refrigeration system as a natural fluid circulation or with a refrigerant pump.
– Due to the small size of dimensions to tube ice banks, it can be used in new installations or in the development of existing installations.
Benefits of using Ice Bank
1- Reducing initial investment
The use of Ice Bank reduces the initial cost of project implementation because:
1-1 In traditional designs, the capacity of the compressor and condenser, etc., is designed to supply the required capacity, while when Ice Bank is used in system design, the design of the compressor and condenser capacity is done in terms of 50% to 60% of the peak of capacity required, because the system is capable of operating for 24 hours during the day, producing and storing refrigerant, and thus the refrigerant needed during the day to supply capacity peak is supplied from the overnight storage place, thus in the case of using Ice bank, there is no need to large compressor or condenser and smaller equipment will be able to meet the capacity need.
1-2 In systems using Ice Bank, since the system is fed by Ice Bank output cold water (near zero degree) which has a lower temperature than the output cold water of Shell & Tube Converters or Plate Cooler. Therefore, the temperature difference between the cold water and the cooling environment has been increased, to provide a certain degree of cooling, less cold water is required, thus the pump and piping required will have less diameter and capacity.
1-3 According to lower temperature of output cold water from Ice Bank than output cold water from conventional systems with Shell and Tube converter or cooler plate and thus increase in temperature difference (Dt), large coils are not required and a smaller cooling coil and a smaller fan will be needed.
1-4 Using a smaller compressor and condenser in addition to reducing the diameter of the tube and valves, it requires less wiring, control, electronic equipment and smaller switchboards.
1-5 If a generator is used to supply backup power, a smaller generator will be needed in systems with an Ice bank due to the use of a smaller compressor.
2-Reducing cost of energy consumption
Using Ice Bank reduces cost because:
2-1- Since in systems with Ice Bank, refrigeration is produced and stored all day long, so there is no need for high electricity consumption during peak hours of electricity and much of the refrigeration required is provided from night storage. Therefore, the cost of consumed electricity is significantly reduced if you use a timed power meter that calculates the cost of electricity consumed at peak hours with much more tariff than midnight.
2-2- In Ice Bank systems, less electrical energy is consumed because refrigeration equipment, including compressors, condensers, etc., has a smaller capacity and size.
2-3 Since most of the refrigeration is produced at night when the ambient temperature is lower than the day, the efficiency of the compressor and condenser increases dramatically and the power consumption against the produced refrigeration is reduced.
2-5- Compressor has a maximum efficiency when it is 100% below load and since in Ice Bank systems, the compressor operates usually under 100% load, so the compressor efficiency is higher in Ice Bank systems and less power consumption compared to production of refrigeration will be needed. It should be noted that in a traditional air conditioning system (with Shell & Tube or Plate Cooler), the compressor has an average load capacity of up to 30% for almost 6 months of the year, resulting in much lower efficiency.
2-5 Reduction of pump capacity as well as the above-mentioned fans in addition to reducing the initial investment cost of the project also reduces the consumption of electricity.
3-Increasing system reliability
In traditional systems, 2 compressors are used to supply 100% of the refrigeration capacity peak per year, each one is capable of supplying 50% of the required refrigeration load, so that in the case of failure in a compressor, other compressor can provide 50% of the required refrigeration. However, in systems with Ice Bank, if the system has two compressors that each provides 30% of the required refrigeration and the remaining, 40% of the required refrigeration to be supplied by IC Bank, in the case of damage in a compressor, the system will be able to supply 70% of the refrigeration required using Ice Bank and one of two compressors. According to ASHREA meteorological data for a routine air conditioning system, supplying 70% peak of refrigeration required annually causes to provide a refrigeration need of collection for 85% of the time during year, so the Ice Bank system have much more reliability.
It should be noted that in the design of refrigeration systems, the maximum amount of refrigeration required (annual consumption peak) for selecting the capacity of the equipment is considered the criterion of designing and calculating, thus providing 70% annual consumption peak throughout most of the year fully meets the system’s refrigeration needs.
4- Need for less maintenance
In systems with Ice bank, maintenance needs is reduced because Ice Bank has much less moving parts than the compressor, so it has less depreciation and requires less repair than the compressor, thus by replacing one of the compressors by Ice Bank, the amount of maintenance and repair required reduces.
5-Protecting the environment
5-1 Power generation at night because of the more efficiency of power plants at night, according to available statistics has about 30% less pollution than electricity generation at night. Therefore, the overnight power consumption that occurs by Ice Bank systems results in less environmental pollution.
5-2- For the reasons mentioned above, Ice Bank systems consume less electricity than traditional systems, thereby reducing the environmental pollution caused by electricity generation.
5-3- Using Ice Bank in Freon systems, due to smaller cryogenic system and less refrigerant use in refrigeration circuit, it reduces environmental pollution due to leakage of malicious Freon refrigerants of ozone layer (CFC, HFC).
The ice storage system consists of one or more coils that are immersed in an insulated water tank. In prefabricated Ice Banks, coils are provided with prefabricated tank and other accessories. In some large refrigeration systems, concrete or metal tanks may be built in place and may only require an Ice Bank evaporator coil. Therefore, Bam Tabrid Sazan Company produces its own refrigeration systems in three ways:
1-Prefabricated Ice Bank (with prefabricated water tank and agitator)
2- Ice Bank Coil
3- Ice Bank Silo (Modular)
In industrial cooling systems that use Ice Bank when there is no refrigeration load or less refrigeration is required (usually at night), by direct injection of refrigerant into the coil, the refrigeration energy is stored as ice around the Ice Bank coil tubes.
When the ice reached the desired thickness, the sensor sends a command to the refrigeration system to stop the refrigerant flow. When cold water is needed for cooling, the circulation pump starts and pumps cold water from the Ice Bank tank to the required locations. The return water circulates inside the tank and cools after direct contact with ice. At the same time to increase the rate of heat transfer between water and ice by the agitator inside the Ice Bank tank, a uniform flow of water over the coils is created.