- Thermal energy storage allows facilities to use less-expensive nighttime power to provide daytime cooling.
- Using off-peak electricity to store energy for use during peak hours forestalls the need to build expensive new power plants.
- Thermal energy storage works in a variety of commercial and institutional settings.
In most areas of the country, demand for electricity peaks during summer, and air conditioning is the primary cause, accounting for up to 50% of power use during the afternoon hours. Unfortunately, electricity is the most expensive during this peak period. At night, utilities have electricity to spare and this off-peak power is often much cheaper. Thermal energy storage is an innovative cooling technique that allows facilities to use less-expensive nighttime power to provide daytime cooling.
The Advantages of Thermal Energy Storage
Cool thermal energy storage (TES) has become one of the primary solutions to electrical power imbalance between daytime demand and nighttime abundance. TES uses off-peak power to provide cooling capacity by extracting heat from a storage medium such as ice or chilled water. Refrigeration equipment is used at night to build a reservoir of cold material. During the day, the reservoir is tapped to provide cooling capacity.
There are a number of benefits to using a cool TES system. Lower nighttime temperatures allow refrigeration equipment to operate more efficiently than during the day, reducing energy consumption. Less chiller capacity is required, which means lower capital equipment costs. And by using off-peak electricity to store energy for use during peak hours, daytime peaks of power consumption are reduced, forestalling the need to build expensive new power plants.
Whether you store cold with ice, chilled water, or some other material, thermal energy storage can help balance the daily ups and downs of electrical power consumption. The technology is straightforward and proven, and the savings can be substantial. Cool TES is one of the most powerful tools available to facilities for reducing demand charges and lowering energy use.
Credit Suisse, an investment banking and financial services company, was recognized by New York State and City officials for installing New York City's largest ice-storage-based air-conditioning system. The system uses a modular product called IceBank, and is projected to lower the facility's peak energy usage by 900 kW. The savings are realized by shifting the electrical load from daytime to nighttime, when electricity is more plentiful and less expensive.
One of the world's largest cool storage systems is located at Chicago's McCormick Place exhibition center. Chilled water storage was chosen for the 2.2 million square-foot annex. Before completion of the annex, the new 8.5 million gallon cold storage tank was already supplying cooling to the exhibit center's two existing buildings. The annex, when completed, was added as part of a single mechanical system. Savings of $1 million per year are projected over the life of the project.