TECHNOLOGY
equaphase Technologies
Eutectic PCM Cool
Storage System
A Eutectic PCM Cool Storage System is a thermal energy storage system that utilizes phase change materials (PCMs) to store and release thermal energy to cool a building.
Equaphase Technologies’ Eutectic PCM Cool Storage systems provide energy conservation, power availability, water conservation and load management to data centers and liquid-cooled facilities.
Achieve chiller-less cooling for most of the year by freezing Equaphase’s eutectic PCMs at night with cooling tower-supplied water. Displace chiller and cooling tower operation during the day while the PCMs melt and cool the facility.
The result: payback periods from under two years to four-plus years. No other storage system, be it an electric battery, ice storage, or any other type of storage system, can slash energy and water consumption and provide low paybacks like the Equaphase Eutectic PCM Cool Storage system.
Equaphase’s high-performance PCMs bring chiller-less cooling and energy conservation to energy storage.
Now, Equaphase Technologies has developed three alternative Eutectic PCMs:
PCM | Freezing/Melting Temperature Range |
Equaphase 16 | 14-16℃ |
Equaphase 13 | 11-13℃ |
Equaphase 9 | 7-9℃ |
The Equaphase PCMs are carefully and thoroughly prepared using patent-pending PCM chemistry and technology. After mixing, the PCM is then filled into containers and hermetically sealed.
These “PCM bricks” are stacked inside a tank, with space for water to flow in between the PCM bricks. The tank can be placed above-grade or below grade, e.g., underneath a parking lot. Piping then connects the tank to the existing cooling tower piping.
Equaphase 16 is particularly appropriate for liquid cooled data centers, as data centers use liquid temperatures in the range of 20-30 degrees C. See ASHRAE’s “Datacom Encyclopedia.”
How Does it work?
Chiller-less Cooling with Fusion Phase Eutectic PCM Cool Storage System
The Equaphase Eutectic PCM Cool Storage System leverages large diurnal temperature differences, along with evaporative cooling tower and water-side economizer technology, to provide the vast majority of a data center or facilities’ cooling loads without mechanical refrigeration or refrigerants, while adding redundancy and resiliency to the facility’s cooling system.
At night, the cooling towers operate, without the chillers, to provide chilled water to the storage tank, where it freezes the Equaphase PCMs and charges the storage tank. The cooling tower, operating alone to supply chilled water, uses about one-fifth the electricity as when the chiller is operated.
Then, during the day, when temperatures are 10 to 18℃ higher, the water is circulated through the storage tank, and the Equaphase PCMs melt and chill the water used to cool the facility through the normal use of the water-side economizer/heat exchanger.
The result: Cooling the data center or facility without the chillers, and saving up to 80% in electricity consumption and on-peak demand. Further, by keeping the cooling towers off during the day, reducing the cooling towers run time, and using the towers at nighttime, water savings (and water treatment costs) can be reduced by up to 25%.
Equaphase Eutectic PCM Cool Storage Systems
Features and Advantages
Beyond Load Management to Energy Conservation.
Equaphase Eutectic PCMs have a high latent heat of fusion, allowing them to store a large amount of energy in a relatively small volume.
Equaphase’s predecessor, a company called Transphase Systems, employed a eutectic PCM with a phase change range of 47-50°F for effective load management in chiller-based air conditioning systems.
Now, Equaphase has added PCMs 13 and 16°C. These higher-temperature PCMs allow for higher charging/freezing temperatures. In some hot/dry climates, the cooling towers will be able to charge the PCMs at night and achieve chiller-less cooling even when it reaches over 100 degrees F during the day!
Eliminates Up to 80% of Chiller Operation
Equaphase uses a cooling tower to freeze a PCM most of the time. For the large majority of the year, Equaphase PCMs require no compressor operation at all.
In contrast, ice storage systems require sub-32 degree charging temperatures.
Space and Energy Efficiency
Compared to a Equaphase tank, a chilled water storage tank, relying solely on the specific heat rise of water with no phase change, takes at least four times the space.
Unlike PCM based systems, chilled water storage requires a large delta T across the load and which may not be available with increased chilled water supply temperatures.
Additionally, a Equaphase system doesn’t rely on maintaining a stratified chilled water temperature gradient inside the tank like a chilled water storage tank does.
Uses A Building's Existing Cooling Towers and Air Conditioning Equipment.
One of the primary advantages of Transphase’s original 47-degree PCM (now an improved Fusion 47) was its ability to be fully retrofitted into an existing facility’s chiller-based air conditioning system.
Fusion Phase’s new PCMs maintain this advantage by utilizing a building’s existing conventional air conditioning equipment, including cooling towers, pumps, and air handlers.
Also, no HCFCs or other refrigerants are added or used in the Fusion Phase PCM Cool Storage system. And the tank’s chilled water can be used in the facility’s fire protection system as well. Most significant, Fusion PCMs provide an added layer of redundancy and protection to the facility’s cooling system.
System Energy Use Comparison
Ice Storage, Chilled Water Storage & Eutectic PCM Storage Systems
EPRl Cool Storage Monitoring Workshop Presentation Material, September 1989
The Electric Power Research Institution (EPRI) produced a Cool Storage Monitoring Workshop report. Using the chiller to charge all three storage mediums, the Eutectic PCM Cool Storage System, using the 48℉ eutectic PCM, displayed significantly lower energy consumption and higher energy efficiency than ice storage or chilled water cool storage system.
Now, with the cooling tower supplied chilled water freezing Equaphase’s new higher temperature eutectic PCMs, chiller energy consumption plummets from about 0.85 kwh/ton-hour (in 1989) to zero for the vast majority of the year!
For further information about Equaphase Technologies, contact us.