There is a cool option that has not gotten too much attention as an efficient and clean way to provide air conditioning: Ice.
Last week, CleanTechnica posted a story noting that the JCPenney has been using ice storage technology from CALMAC at its headquarters for a quarter century. The piece — a Q&A with CEO Mark MacCracken — said that its IceBank technology saved the retailer $100,000 last year at its Plano, TX, headquarters.
Though it is a bit surprising to think of ice as a storage media, it makes sense. Indeed, the idea is simple. “Ice storage is a tool for dramatically reducing peak demand, which is the utilities’ real problem, while possibly also saving energy,” wrote CALMAC CEO Mark MacCracken in response to emailed questions from Energy Manager Today. “The energy savings vary by installation application. One way it saves energy is it shifts usage to nighttime generation which in most areas of the country is much more” than generation during the say.
The National Security Agency explains the approach clearly:
Ice storage technology, also known as thermal energy storage (TES), delivers smart, grid-ready, efficient storage solutions. It does this by freezing water at night, when power demands are lowest, in refrigerator-like boxes and then using that ice during the day, when power demand is highest, for utilization with various cooling operations. By storing energy off-peak, when electricity generation is cleaner, more efficient and more abundant, then delivering it on-peak when it is needed most, represents how NSA is committed to utilizing new and sustainable energy solutions.
The market is not huge, but is growing significantly. At the beginning of the year, Transparency Market Research said that the sector would expand from $600 million in 2013 to $1.8 billion in 2020. The compound annual growth rate (CAGR) from 2014 to 2020 is projected to be 16.7 percent, according to the firm. The drivers, the report says, are the expansion of variable energy sources – renewables that are inconsistently available such as solar and wind – and demand for electricity. The study says that investments and interconnection barriers exist, however.
Another CALMAC installation is the Alachua County Library Headquarters in Gainesville, FL. Earlier this year, the company announced the installation. The approach is to create the ice during nighttime when it is cheaper to produce. When air conditioning is needed — presumably, the next day — it is provided by the melting ice. CALMAC says that the approach is 68 percent cheaper than instantaneous cooling. The release says that electric demand is cut in half. This, it says, is a significant reduction since 40 percent of electric costs are due to cooling. These systems, which do not work for heat, are as beneficial for their environmental benefits as their ability to cut costs. “Ice storage can save energy, however, the main purpose is to store clean energy to be used when it is most needed,” wrote MacCraken.
Another company that offers ice-based technology is IceEnergy. The company, which is based in Santa Barbara, CA, offers residential and commercial systems. “During off-peak hours, both systems store cooling energy by freezing water in an insulated storage tank while the conventional AC provides cooling as needed,” according to CEO Mike Hopkins. “During peak hours, ice-chilled refrigerant circulates from the Ice Bear to the air conditioning system, eliminating the need for energy-intensive compressors. The result is a reduction in peak cooling load by 95%, with 100% round-trip efficiency.”
A abstract of a paper published in 2015 illustrate the efficiency of ice thermal energy storage and phase change material (ITES and PCM):
The results have illustrated that the power consumption of ITES and PCM systems are 4.59% and 7.58% lower than the conventional system respectively. Moreover, CO2 emission production for ITES and PCM systems are 17.8% and 27.2% lower than conventional system respectively.
It appears that using ice as an energy efficiency tool is beneficial for energy managers and the buildings the serve. The bottom line is that it uses something that nature does naturally – transition something to a form that can be stored for later use – offers some very cool advantages.