An ice bank or ice tank is a device that makes and stores ice during off-peak hours so that it can be used during peak hours. Several parameters are considered to calculate the ice bank.
Several important factors in the design of an ice bank are introduced, as follows:
- Calculation of the refrigeration load profile
- Working and control strategies
- Parameters of the electrical equipment used
Function and maintenance
Aghayari machine-made ice banks are calculated and designed based on the needs of each project. The refrigerants that can be used in an ice bank can include: ammonia, ethylene glycol, various types of freons, propylene glycol. The ice bank is made of copper and aluminum, stainless steel, and steel.
The ice bank system consists of devices and equipment, some of which we will mention:
- Valves and controllers
- Compressor, chiller and condenser sets
- Galvanized ice bank coil, copper coil
- Insulated water tank
- Electrical panel
How the ice bank works
The ice bank includes various devices that produce ice on the surface of the evaporator coil tubes floating in an insulated water tank. The ice formed on the surface of the heat exchanger reduces the temperature of the water circulating around it. After the ice is stored in the ice bank tank, it is time to consume the stored cold. The required water, the temperature of which is to be reduced, circulates in the ice bank tank with the ice formed in the pipes or plates, transferring heat to the ice and reducing its temperature. After the water temperature increases again, it is returned to the ice bank by the pump to melt another amount of ice and lose heat and be used again.
The lower the temperature change per unit of energy received, or the specific heat of the fluid selected as the fluid inside the tank, the higher the ice bank capacity. This fluid is easily and abundantly available because its heat capacity and latent heat of melting are high. Another factor affecting the ice bank capacity is the quality and thermal properties of the tank's insulation. The lower the thermal conductivity of the insulation and the greater its thickness, the less energy loss from the tank will be.
The water inside the tank expands when it freezes, increasing its volume by approximately 9%. For this reason, the amount of water in the tank must be within the appropriate range so that it does not damage the body by increasing its volume.
The exchanger inside the tank is designed in such a way that ice is formed uniformly in the parts of the tank, so that water moves freely during the process and is not trapped between the ice. Ice making in a standard ice bank is done at night, the glycol solution flows between the ice bank heat exchanger and the chiller, but there is no flow in the coil. The glycol water solution is cooled by the ice bank during the day. To keep the outlet temperature constant, a temperature adjustment valve is used to adjust the refrigerant leaving the ice bank to keep its temperature constant at a level that the ice bank is capable of producing.
Energy optimization
Cooling systems are suitable for storing cooling at night and using it during the day to cool equipment. During the day, when electricity is produced at a lower cost, the chillers cool the fluid and store it as ice or cold water. Considering that electricity consumption is more expensive during the day, the chiller is turned off, and if needed, the energy stored in the ice bank is used.
Ice bank is designed and manufactured in two models:
With chiller: The refrigeration cycle equipment in the chiller is activated at night, using this process, it leads to ice formation in the tank. During the day, if the cooling power of the ice bank is not sufficient, part of the chiller power is activated to help the water cooling process.
Independent ice bank: In this model, the ice bank has all the equipment, including the compressor, condenser, etc., and the required cooling is provided by it.
Application of ice bank
It is a new design that has a significant impact on reducing energy consumption, which leads to solving the major problem of high energy consumption of chiller and cold storage devices. This system is used in various industries, including food, beverage, juice production, and for pasteurizing products at low temperatures, chemical, cold storage and pharmaceutical industries.
Advantages of using an ice bank
Cost reduction: Using an ice bank in a system causes the electricity consumed at night to be recorded, thus reducing energy costs.
Low maintenance requirement: This device has very low depreciation and has a long lifespan, and in the long term, it requires opening and cleaning.
Disadvantages of an ice bank
Large weight and volume: Due to its high energy storage capacity, it also has a large volume. The length of the heat exchanger tubes inside the tank is long due to the need for a high heat exchange surface, which is why the weight of the ice bank is high.
Cost-effectiveness: Using an ice bank in small systems is not economical at all. In large systems, the cost of control and cooling equipment is low compared to the cost of the refrigeration system, but in smaller systems, the cost of control equipment can account for a high percentage.
Aghayari Machine Company, relying on modern technical knowledge and expert staff, has been able to provide customers with a variety of refrigeration systems and ice banks with the best quality. This system is designed and calculated with complex angles while being simple. Therefore, it is better to seek advice before purchasing an ice bank.
Our experts will recommend the best and most economical one to you, considering the capacity, type of refrigeration, and equipment that is suitable for you.
