Ice Tech Enables Time-Shifting for
Single-Family House Cooling

Everything from A to Z in Azusa including Downsized Chillers

By Derek Handova

On some power grids, such as those in California, air conditioning (A/C) can be 30 percent of the total electrical system demand, according to James White, partner at PAC Partners, majority shareholder in Ice Energy, a manufacturer of small-scale commercial and residential energy storage systems. For a long time, skyscrapers, college campuses and other large complexes of buildings have been able to deal with this problem with ice chillers. The basic idea with ice chillers is to freeze water overnight when electricity rates are “off peak” and then melt the water during the day to cool the air for buildings when it is the hottest. And while the amount of electricity necessary to cool air is about the same with ice chillers as compared to air conditioning, ice chillers accomplish it with the much cheaper electricity available in the wee hours.

Ice chilling technology works by freezing water overnight when electricity rates are “off-peak” and then letting it melt during the heat of the day to cool the air, saving money and power capacity for more important uses. Image courtesy of Ice Energy. Photo editing by Dove Printing

However, this concept was not an option for single-family homes until recently, according to White, who also serves as the CFO of Ice Energy. Since 2003, Ice Energy has made a smaller-scale version of an ice chiller called the Ice Bear, intended for medium-size buildings up to four stories tall. Then beginning in August 2014, Ice Energy started to prototype the Ice Cub, a version of the Ice Bear for single-family homes, according to White.

“The Ice Bear is the Ice Cub’s big brother,” White says. “The Ice Cub is modular and has a smaller form factor than the Ice Bear.” With the Ice Cub, ice-chilling technology helps even out the electrical transmission load during hot summer days to cool air for use in residential buildings.

“This is one of the few applications I have seen where someone is attempting to provide energy efficient cooling,” says Jeff Haydock, president and CEO of ecoCFO LLC, provider of CFO services to energy and environmental businesses. “Most companies are attacking the heating component first.”

Everything in the USA, including research for air-on-ice
Having a relationship with Azusa Light & Water previously in place for the Ice Bear, the city-owned utility in Southern California made the perfect partner to test the new Ice Cub, which is still in the prototype stage. “Azusa asked for the Ice Cub,” White says. “They wanted the prototype, and they helped us find the individual homeowners to test it.”

The Ice Cub is part of a research project to help verify potential thermal energy storage systems for residential applications. It is supported by a technology research grant from the American Public Power Association (APPA).

“We are excited to explore the tremendous potential of (Ice Cub) residential thermal energy storage cooling applications on behalf of our citizens and the more than 2000 members of APPA who helped fund this project,” says George Morrow, general manager of Azusa Light & Water. “The future savings for individual residential customers could be significant and even more importantly, when deployed at scale, (Ice Cub) residential thermal energy storage systems in cooling applications could cut untold millions from the peak power expenses of municipalities across the country.”

Right now, two prototype Ice Cub units are operating at Azusa residential customer premises. “If the data looks good, they will run for a couple of months,” White says. “Then there will be more with Azusa and more with other utilities.”

California mandate for energy storage and more
Ice Energy sees an opportunity for residential ice chiller technology with the publication by the state of California for mandated energy storage with a target of 1.325 gigawatts by 2020. “That translates to a market potential of $10 billion,” White says. “The Ice Cub lets us install ice chilling technology in any residential housing, except for apartment buildings.” For large apartment buildings, the Ice Bear would be more appropriate, perhaps.

However, others are more cautious about the market potential. “The thermal energy storage market is so young that the market size changes daily,” Haydock says. “Variables driving this are: Equipment and installation cost variations, changing regulations, evolving technologies, new markets opening up outside of California and a handful of others. Pinning a market size to it is very difficult. It is a market with great potential that is mostly untapped and in the early stages of development.”

Beyond the California energy storage mandate, the state is also requiring a dramatic reduction in carbon emissions by 2020. And soon federal rulemaking will come into play for the rest of the nation with the Obama Administration emission standards recently approved by the Supreme Court. Azusa and other electrical companies could use Ice Cub technology to cost-effectively comply with all these governmental interventions, according to Ice Energy. With 20 million operating hours combined, Ice Bear and Ice Cub technology has been thoroughly field-tested.

A/C vs. ice chilling: Just what makes people feel cool?
In the hottest climates, A/C can struggle to quickly cool the insides of buildings. At best, A/C only provides a 10 to 15 degree temperature differential against the external atmosphere. On the other hand, ice-chilling technology can provide a 20-degree or greater heat differential from the outside, according to White. As a side benefit of ice chiller technology, psychologically people think the cool air it provides is much colder compared to A/C-cooled air. “Turns out what people perceive as cooling mostly comes from dehumidification,” White says. “Ice Cub dehumidifies air more efficiently than A/C.”

The high-tech guts of the Ice Bear thermal energy storage system belie a simple concept: it is more efficient to freeze water for cold air than to cool air directly. Image courtesy of Ice Energy. Photo editing by Dove Printing

Easy for utility customers to sign up
For Azusa and other utilities’ customers participating in the Ice Energy thermal storage project, it will be very easy to sign up. “The utilities will say ‘Hey Mr. or Ms Customer do you want an ice chiller to lower your power bill?’ and the customers usually say ‘great’,” White says. Then the utility gets the benefit of additional peak capacity, and the customer gets a lower power bill. The ice chiller concept requires a little explaining, but the utilities will buy the Ice Cubs and Ice Energy will site them at customer locations. At present, there is no formal program set up for participation, but let Ice Energy know what you think.

Background Photo credit: pratt / Foter / CC BY-NC