Baltimore Aircoil Co.’s Ice Chiller thermal storage coils are lowered into a field-erected tank in Baltimore.

Energy use - and how to cut back on it - is a hot topic these days. As more consumers seek ways to lower their utility bills and reduce their environmental footprint, contractors need to be prepared to offer them new energy solutions.

One solution that is gaining popularity across the commercial market is ice thermal storage. The driving forces behind this technology include government and utility programs, as well as other green initiatives.


The basic idea behind thermal energy storage is to even out the distribution of how and when a consumer uses energy. John Lau, manager of thermal storage for Baltimore Aircoil Co. (BAC), explained the fundamentals of the technology: “Ice is built overnight, when energy costs are at their lowest, and then during the day, particularly during peak usage hours, the ice is melted, providing chilled water for air conditioning, district cooling, or process cooling applications.”

According to Therese Wells, director of marketing for Ice Energy, this technology levels the demand for energy by “shifting significant amounts of energy usage from peak to off-peak periods.” She noted that daytime use of air conditioning is “the single largest component of peak energy consumption,” so using efficient nighttime power can result in dramatic savings. “For the individual building owner, air conditioning energy demand - typically 40 to 50 percent of their electricity use during peak hours - can be reduced by as much as 95 percent.”

In addition to the energy savings, Wells also pointed out that thermal storage is unlike load management cycling or other programs that require consumers to change their behavior and can have a negative effect on their comfort or productivity. She said, “Our solution permanently shifts energy use from high-impact daytime hours to low-impact nighttime hours, enabling commercial buildings to slash peak electricity demand, manage energy costs, and improve their environmental footprint without compromising comfort.”

BAC’s Ice Chiller thermal storage units are constructed of heavy-gauge galvanized steel panels and insulated to provide a total insulating value of R-18.


According to Lau, the acceptance of thermal storage technology is being driven by the government and utility companies, as well as the overall green movement.

He pointed to a bill introduced in the Senate last June that intends to reduce peak electric demand and lower greenhouse gas emissions. Called the Storage Technology of Renewable and Green Energy Act of 2010, “the proposed bill would provide tax credits to businesses that invest in and use thermal storage,” Lau said. Although this bill was stalled in committee after its introduction, it is indicative of the growing support for thermal storage. “Government incentives and credits would make thermal storage more beneficial for a wider range of businesses,” Lau said.

Utilities are also driving the adoption and development of thermal storage. “Many utility companies are reinstating financial incentives and/or implementing time of day rate differentials to cut peak energy demand and to encourage load shifting from peak to off-peak usage times,” Lau said.

According to Wells, Ice Energy’s systems are being purchased by utilities and provided at no cost to building owners. Early this year Ice Energy announced an agreement with the Southern California Public Power Authority (SCPPA) to install more than 7,000 of its storage systems for SCPPA member utilities on approximately 2,000 commercial, industrial, and government buildings throughout Southern California.

“Other green initiatives continue to be driving forces,” Lau added. These green influences include the growing popularity of solar and wind power, as well as LEED certification. Storing energy produced by the wind and sun can alleviate the logistical problems caused by the inconsistent nature of these power sources.

Lau also noted, “Utilizing ice thermal storage with low temperature air can reduce energy consumption for an HVAC system and may qualify a building to earn a significant number of LEED points for improved energy efficiency, air quality improvement, and low sound pollution.”

Ice Energy’s Ice Bear is a distributed thermal energy storage system designed for use with direct expansion air conditioning systems on commercial buildings.


A wide variety of customers are beginning to turn to thermal storage to solve their daily cooling needs. According to the manufacturers, their equipment has been installed in a range of facilities, including office buildings, schools, hospitals, malls, big-box stores, convention centers, sporting arenas, data centers, universities, airports, libraries, and more.

Contractors seeking to service these commercial customers should be knowledgeable of the technology of ice thermal storage so they can properly provide customers with this option.

“While it is a simple system, it is important for HVAC contractors to be thoroughly familiar with the system components and, in the case of ice thermal storage, the glycol fluids being used within the system,” Lau said. “Ice thermal storage units typically use a 25 percent (by weight) solution of industrially inhibited ethylene/propylene glycol for both corrosion protection and freeze protection. Uninhibited glycol and automotive antifreeze are not to be used on thermal storage applications.”

He added, “The controls of an ice thermal storage system are also more complex than traditional HVAC systems, and an understanding of the optimum operating strategies for ice melting and ice building will aid in successful installations.”

On a final note, Wells added that contractors should strive to learn more about utility-sponsored programs in the areas they service that will help to drive their customers to adopt this technology.

Publication date:11/08/2010