Thermal Energy Storage Systems: as a backup system for air conditioners

Technology advancement has led to people awestruck by the luxury of. With the world growing air conditioners has become an essential requirement. Due to the growth of industries, the demand of the grid’s power supply is alarmingly large. There are more power interruptions across the country are due to the an obvious demand-supply imbalance, rise in tariffs for power and new tariff strategies like the time of day (TOD) demands storage of energy. DG Sets as well as Inverters/UPS have been used for a wide range of purposes for quite a while but there was not a option for cooling prior to. The storage of energy through thermal (TES) seems to be the most well-known solution.

What is the reason? Thermal Energy Storage?

Cooling can be utilized in both industries and at home. It is essential that man can live an enjoyable life. The house is cooled in the summer months, refrigeration to preserve food , etc. is a necessity for the common man. However cooling needs within industries has increased. For instance the chemical industry requires cooling to keep chemicals in a controlled state.

Air conditioners operate on electricity. The need for electricity has increased through the decades. In turn, the demands on the power grid has increased dramatically. This has left us in an enigma that the demand can’t be satisfied by the supply from grid, which results in a shortage of energy. In this situation, thermal energy storage is the ideal solution to meet increasing energy demand. It’s used to manage energy consumption during both off and peak times. It is also able to reduce dependency of DG set-ups and even inverters during power outages.

How do utilities handle the peak demand by using the TOD (Time of Day Tariff)

For utility companies or distribution businesses, it can be very costly to purchase power at times of high demand if the power supply is not sufficient to satisfy the demands. The speed that electricity is sold is not economically feasible for distribution companies that sell electricity to offer power at the same rate. Therefore, utilities have an entirely new tariff scheme known the Time of Day (or TOD) tariff. In this plan electricity costs are higher in peak hours, but lower when it is low-consumption. This type of tariff plan can be used in all states for industrial setup and certain states, commercial setup is permitted too. This means that using TES in times when electricity costs are low will help to save money in times when electricity is costly. To learn more about the TOD tariff , read this article.

Where is TES being used?

  • The TES is used to provide electric power during peak demand. It is responsible for the peak demand while the grid is used to provide all the load.
  • The TES is also a viable option in the event that the cooler installed isn’t able to provide the requirements for capacity. The TES is used in conjunction with the cooler that is installed to provide the system with power.
  • Sometimes, the TES can serve as a stand-alone system to cool.
  • Similar to how an UPS is a computer’s backup the TES can also be used to backup the cooling system installed during power outages.

What exactly is the TES system function?

The thermal storage of energy is a tank filled with an energy storage medium. It is equipped with a cooling system that is used to cool the entire system. Tubes and pipes connect the TES system to cooling units. The medium used for storage is usually water. It is chilled down to low temperatures in times that are not in high demand, through direct cooling. This energy is then conserved in the media until it is released. If the demand is increasing the hot air is allowed to flow into the tanks. It absorbs cold through conduction. The cold air is then transported into the cooling system via connecting tubes or pipes.

There are a variety of TES types available on the market

Storage of chilled water:

In this instance the heat capacity that is sensible to water is utilized for energy storage. Energy is stored at temperatures of 4 to 5 degrees Celsius.

Ice Storage:

It utilizes the concept of latent heat the fusion of water in order to preserve energy. It stores energy at zero ° Celsius. Other fluids known as charging fluids can be mixed into the water to keep it at -5 degrees Celsius. Charging fluids function as anti-freeze substances that stop frozen water.

PCM Storage:

In this manner the phase changing substances are contained within nodules. Nodules are hollow, spherical forms. They are frozen at certain temperatures. This concept is employed in TES to chill the system.

Molten Salt Energy Storage

In this kind of storage, molten salt can be utilized as a method of storage. It is efficient of 99 percent and is employed in a lot of cases in conjunction with the Solar Tower to store thermal energy.


Full Storage:

In this operation mode the TES shifts all load off of peak hours. It works at its full capacity to charge during non-peak times. In peak times it is fulfilled with the TES. The chiller isn’t running.

It is advised to use it only in situations where the charges are very at their highest during peak conditions.

Partially storable:

If the capacity of the chiller is less than the load, the chiller takes some of the peak load, while the TES will take the remainder. In this case, the chiller operates at its full capacity throughout the day. When the load is lower than its capacity TES conserves energy. When the load is greater than capacity TES releases energy.

It is most effective in situations where the load at peak is significantly over the average load.

Space is needed:

With the way TES operates TES it is contemplating what space the system could take up. There isn’t any space. It is comparable to the water heater in your home. A typical 1750 sq. feet. home is equipped with a 4 sq.ft. water heater. The water heater is powered by (4 sq. ft. / 1700 sq. feet.) is only 0.23 percent of the floor area. The 70 square. feet. tank can cool around 10,000 sq.ft. and require around 0.70 percent of floor space to store the full amount of. The majority of thermoelectric storage units are part storage systems that use storage to account for around 30 percent of the total cooling requirements, thereby reducing the floor space required to around 14 of of area that is conditioned.

Maintenance is required:

The TES isn’t a device that requires a lot of maintenance and only needs minimal maintenance:

  • The coolant concentration should be monitored each year. A once-a-year test is performed to determine the amount of corrosion inhibitors as well as the amount of anti-freeze agents (if necessary).
  • The cooling water has to be properly treated to achieve maximum efficiency.

The advantages of using the technology

  • The TES system utilizes it’s Time of Day (TOD) tariff to gain. It is charged at evening when the rate is low, and then releases in the morning when the it is at its highest. It also decreases the price of electricity. Air conditioning is the largest component of most commercial electricity bills. TES helps to reduce the cost of electricity by reducing.
  • Utilization for DG set and Inverters which are expensive and inefficient, could be avoided with TES. Additionally, the pollution from DG sets could be removed through TES.
  • With TES strengthening the standard chiller, the size of the cooler can be reduced. Therefore, the expense of the installation of chillers is decreased. That is that the capacity of the coolers is increased for the same price.
  • The quantity of refrigerants used by conventional chillers is very high. It is possible to reduce this by installing TES.
  • The TES also decreases electricity consumption
  • In the absence of emissions, the TES is made eco-friendly
  • In the end, the TES is extremely reliable and efficient
  • Certain utilities offer benefits the use of TES systems in commercial settings.

The drawbacks of TES

  • TES Systems are expensive to purchase. They are usually employed in commercial settings where electricity rates are greater and therefore their payback time is shorter. However, they are also used in residential settings however, the paybacks are more lengthy.
  • Systems for TES are not accessible for smaller requirements (they generally only come in the sizes of 3 tons and higher) and can therefore only be used for larger installations.


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