Trends: The growing thermal energy storage market for comfort cooling
June 27, 2017
According to P&S Market Research, the HVAC market is growing at a considerable rate. Within the HVAC sector, Credence Research reports that the thermal energy storage market is expected to have robust growth, especially in Europe due to increasing expenditures on renewable energy resources. Solar-plus-storage could see a net worth of US$49 billion in ten years. And the market for district cooling systems, made more cost effective with thermal energy storage due to low temperature abilities, is on course to reach $80Billion by 2026 according to Research and Markets.
Why all this predicted growth for a mature product line? Customer preferences for cooling comfort, climate change and advances in controls are all to blame.
I. Customer preferences for comfort cooling
Customer preferences for climate controlled spaces have changed over the years as more people adopt comfort cooling. Around the world air-conditioning demand is fueled by an expanding middle class. Air-conditioning is growing more profoundly in developing countries, according to Infiniti Research.
The biggest country for air-conditioning growth is India, where there is extremely hot temperatures and little installed cooling capacity. New sprawling IT campuses require substantial cooling. Due to their high volumes plus a need for flexibility and reliability centralized district cooling systems are gaining importance. In the Middle East the district cooling market is set to grow by 18% as their construction market is growing faster than any other region in the world. In the U.S., the LEED Certified development Encore! utilizes thermal storage as a key sustainability features for its district cooling system.
Utility load factors
For Americans, cooling is a mature technology that uses a massive portion of the building’s electricity consumption. When air-conditioning began in the U.S., utility load factors were closer to 70%. Load factor is defined as average electric grid demand divided by peak demand available. It’s a measure of utilization. Over the years, air-conditioning use has caused the demand for summer afternoon electricity to increase causing summer peak demands. Utility load factors have been shrinking because new generation has been built to handle the summer peak demand, but those peak demands don’t occur for most of the year. Think of a 50% load factor this way, IF we could use electricity at a steady rate both day and night, there are twice as many power plants as we really need.
The low utilization or low load factors economically burdens the grid and stresses transmission and distribution systems resulting in higher electricity costs and increasing greenhouse gas emissions as utilities acquire more reserve capacity to meet peak demand for summer cooling loads. To illustrate the problem, ISO New England reports that the top 19% (5MW) of the total peak demand was only responsible for 2% of the total hours of the year in 2016.
A secure & stable grid
Reliability is the number one job for electric utilities. Reliability is accomplished by balancing demand with supply and the proper amount of reserve capacity. Utilities must keep lights on and people comfortable, a task which become increasingly more difficult as load factors worsen due to air-conditioning loads and more recently a higher portion of the generation mix coming from intermittent renewable energy. In a recent statement a California utility urged customers to reduce peak demand. Deborah Affonsa, vice president of Customer Service at PG&E, stated “The single biggest step that customers can take to keep the power flowing is to reduce the use of their air conditioner.” The utility program predicts to set new system peak load levels that surpass decade old peaks.
To reduce air-conditioning use during summer peak periods businesses can employ the use of demand response and/or smart air-conditioners. According to GreenBiz, the potential is even larger with thermal storage — ice-storage air-conditioning. Buildings with thermal ice storage provide grid stewardship and contribute to grid reliability while lowering costs. Buildings without energy storage contribute to grid instability and will pay almost twice as much to cool their spaces. That why thermal energy storage has been adopted by so many businesses and schools, keeping people comfortable all over the world. <Watch how this school district reduced their utility costs by $5 million a year with thermal energy storage upgrade.>
II. Climate change effect on air-conditioning demand
Another factor impacting industry trends for thermal energy storage ice cooling is rising temperatures. According to the Climate Reality Project, “Since 1970, average summer temperatures in the South have risen by as much as 3.3ºF – with many of the fastest-warming areas in Texas. Presently, Houston experiences about five days each year over 100ºF. By 2100, the city could expect some 70 days over 100ºF under a high-emissions scenario, and an average summer temperature increase of 5.7ºF. Think that’s a far-off scenario? During the 2011 drought, many locations in Texas experienced more than 100 days over 100ºF.”
Look at this graph from the National Climatic Data Center. Peak temperatures are rising.
Rising temps are widespread as the following map shows.
Due to climate change, governments around the world have been investing in more environmentally friendly solutions to offset increased energy use. The effects of climate change will be more severe as heatwaves become deadlier. Those most affected are those without access to air-conditioning. In South America, countries where it is already hot and humid, will see more deadly conditions with just small increases in temperatures. Around the world, excessive heat can result in flight delays and national emergencies.
In order to lessen the impact climate change eleven local U.S. state governments have vowed to seek reduction in greenhouse gas emissions and uphold the Paris Agreement. In March 2017 wind and solar accounted for 10% of U.S. electricity generation for first time according to the Energy Information Administration. Globally, renewable electricity generation, excluding hydro, accounts for 8% of global electricity generation.
The state of energy storage
As climate change is made manifest and renewable resources grow so does the market for energy storage. Energy storage is vital to buildings and the grid for its ability to supplement the intermittent characteristics of wind and solar.
With solar and wind on the rise, energy storage legislation has been passed in states such as Maryland, Massachusetts, New York, California, Connecticut, Hawaii, Minnesota, Nevada, Oregon and Arizona. Even broader support for energy storage is seen among most utilities who are closing their coal and nuclear plants and whose rate structures reward businesses who permanently shift cooling loads from peak demand periods.
Some utilities offer a special rate or incentive for thermal energy storage or peak load reduction driving businesses and schools looking to reduce their energy costs to adopt thermal energy storage.
Over 1 GW of thermal energy storage is shifted from day-time to night-time periods in commercial buildings. Thermal storage systems capture wind energy at night to store cooling for use the next day. Ice thermal storage systems can be controlled to kick on when rates are high, when the sun isn’t shining, when a chiller is down or when the grid is congested without any loss in comfort to the building occupants.
A typical thermal storage system combines a simple tank full of water with a standard piece of air-conditioning equipment called a chiller. Akin to a hybrid car, the chiller acts like the engine for the cooling system and the storage tank is like the battery. The two work together to create and store cooling when it is most cost effective to do so, during periods of high cooling demands or high prices. The brains behind the thermal storage systems are the controls.
III. Advancements in controls
Because of the system’s built in demand flexibility to store cooling when the grid isn’t peaking and electricity prices are low, the controls for chiller plants with thermal storage provide operators with powerful, custom options for how to operate their system most effectively. System operators can decide when to store the cooling based on electricity rates, building occupancy, weather and solar or wind variability. Operators can decide which mode of operation is best, run the chiller, discharge the storage, or use the chiller and discharge the storage, charge, or charge and cool.
Knowing when its best to run which equipment can take some planning from a trained HVAC engineer who understands the building, its operation, and the utility tariff which is why having a dedicated system partner to commission the thermal storage system can pay big dividends. At the same time, the tanks are simple enough to run that many large churches store ice in thermal storage tanks to lower operating costs.
Over the years, new upgrades in controls have improved overall system performance of thermal energy storage systems by making the customer interface more user friendly and easier to control. Peak energy usage can be monitored simply on screen - remotely or on-site. Real-time data monitoring can provide unsurpassed data flexibility over when cooling is stored or discharged to provide the most energy cost savings along with diagnostics aid in preventive maintenance of the ice energy storage enabled chiller plant.
Alerts can be set to notify operators of peak energy thresholds and chiller downtime. Web-enabled data can help predict future load schedules based on weather predictions. Data can later be analyzed for future opportunities to fine tune system efficiency. New settings can also be programmed to adjust automatically based on building parameters important to the user (occupancy, electricity rate schedules) in order to maximize comfort and energy costs. For net zero buildings, rather than have sporadic unpredictable levels of power due to solar or wind, buildings can manage energy use effectively.
New clean energy economy
Today’s air-conditioning systems are smaller, quieter and smarter than a decade ago. New controls can offer more intuitive control and better data to provide greater operational costs savings and help customers take advantage of changing electricity rates. State of the art ice air-conditioning equipment used to store and shift energy use can provide even more opportunities for savings as temperatures rise, more people adopt air-conditioning and renewable energy resources grow. With our warming world ever more reliant on smart technology, smart air-conditioning systems will provide the needed grid reliability and demand flexibility and control expected by today’s consumers in the new clean energy economy.
