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Save Time, Energy and Money with Thermal Energy Storage

 September, 6th 2017     Comments     Views

By Dr. Marcel Christians

The cold storage, refrigeration and process cooling industries are known to have very high operational expenses in order to, simply stated, keep things cool. When it comes to energy storage, the cold chain is a demanding logistic segment, mostly due to its requirements for capital-intensive equipment, strict temperature tolerances, and large energy demand. The cold storage industry is also very conscious of uptime, as a loss of cooling doesn’t just imply temporary end-user discomfort, but can result in financial impact from spoiled perishable goods or the loss of extremely low availability medicines, vaccines, blood supplies and organs. Cold chain operators, therefore, are always looking for new ways to balance the energy-intensive requirements of expensive, perishable consumer and medical products with the need to manage energy consumption and cost.

Commercial refrigeration and process cooling are also industries in which the ability to manage energy consumption has attracted attention. A report by National Grid reveals that refrigeration constitutes an average of 54 percent of end-use energy consumption in supermarkets across the United States. Furthermore, the Freedonia Group recently forecasted that the global market for commercial refrigeration equipment is set to increase 4.5 percent per year through 2020, to $35.3 billion.

Much of this growth in demand is due to the necessary replacement of equipment damaged by constant compressor cycling that refrigeration systems experience under typical operation. Instead of implementing these costly repairs, however, managers should consider a new alternative to reduce energy consumption and cost: cold thermal energy storage.

Thermal energy storage (TES) systems can help operators achieve multiple objectives in this demanding space by increasing the reliability of their cooling redundancy, decreasing emergency energy requirements, managing utility demand charges and time-of-use rates and by providing improved humidity control.

What is Thermal Energy Storage?

Thermal energy storage systems are not new. In fact, different shapes and forms of TES can be traced back as far as ancient Rome. High-efficiency, low-cost, cold thermal energy storage systems, however, are a novel and innovative solution to today’s cold chain and refrigeration energy management challenges.

TES systems absorb energy when it is abundant and cheap, and deliver it during periods of peak demand when energy is more scarce and expensive. Thus, a TES-enabled system delivers energy at a fraction of the cost required to run a traditional cooling or refrigeration system. In regards to refrigeration and process cooling, this translates to a 75 percent reduction in compressor cycling during the highest demand periods of the day.

Identifying the Application

Modern implementations of cold thermal energy storage have been traditionally divided into two distinct categories. The first are large-scale applications, in which the TES system is custom designed for the application. This is typical for skyscrapers or hospital buildings. The second are smaller-scale applications, in which pre-sized TES devices are purchased off-the-shelf and retrofitted to the system. This includes smaller commercial buildings or residential applications.

For process cooling and refrigeration applications, the TES system can be incorporated into both the single-stage and variable refrigerant flow (VRF) systems used in commercial and residential HVAC and commercial refrigeration systems. In these cases, the TES system can seamlessly integrate with existing supermarket, commercial refrigeration or process cooling chillers. Ideally, it can also be used as an independent source of cooling for intermittent, or batch, applications that only run a few hours of the day.

Defining Real World Value

From an economic standpoint, using TES systems to shift usage to off-peak can generate significant end-user savings. In Southern California, Ice Energy installed a fleet of seven Ice Bears at a site in Riverside for an HVAC application and, in turn, has reduced the end-user’s electricity bill by $3,200 per month.

Another use case of particular value to the process and cold storage industries is the availability of low-power, high-quality backup cooling in case of power interruption. In standard designs, a back-up generator sized to handle mission-critical duties needs to be available to take over at a moment’s notice. A high-efficiency refrigeration and process cooling solution helps to achieve this by drastically decreasing power consumption requirements. This allows the system designer to potentially eliminate cooling from the generator load by bundling the TES system with an appropriately sized chemical battery.

Santa Barbara-based Ice Energy has developed several new ice battery solutions for supermarkets, process cooling and the general commercial refrigeration market based on its proven line of storage products for HVAC applications. These storage systems, designated the Polar Bear line, can be used in applications as diverse as cold room air conditioning (including 0˚F cold rooms) and fermentation process cooling in wineries, breweries or distilleries.

With new high-efficiency TES systems based on a proven track record in the HVAC market becoming available, cold storage operators can now leverage this technology to increase the reliability of their systems, cut operating costs and decrease CO2 emissions – and ensure the cold chain remains intact. 

Dr. Marcel Christians serves as Ice Energy’s Chief Technology Officer. Dr. Christians currently leads Ice Energy’s effort to develop a comprehensive suite of energy storage, cooling and heating solutions for global residential and C&I markets covering the refrigeration and comfort cooling spaces. Prior to joining Ice Energy, Marcel worked at Carrier Corporation’s Technology and Components Division where he designed and developed disruptive heat transfer technologies and systems for the chiller market. Marcel holds a Ph.D. in Mechanical Engineering from the École Polytechnique Fédérale de Lausanne, in Switzerland, where he studied under the tutelage of world-renowned heat transfer expert Prof. John Thome. He graduated Magna Cum Laude from the University of Pretoria, in South Africa in 2005 with a M.Eng. in Mechanical Engineering.