The patented cold thermal energy storage (CTES) system from Lancashire-based Organic Heat Exchangers (O-Hx) is undergoing full working trials at the Alnwick site of Quotient Sciences, a drug development and manufacturing accelerator, and has already delivered significant benefits and savings after being installed alongside an existing chilled water system.

EnergiVault consists of a charger, powered by Bitzer compressors, and thermal battery. The charger’s ice crystallisers charge the battery by converting up to 60% of the system’s heat transfer fluid (HTF), a water/glycol mix, into spherical ice crystals a fraction of a millimetre in diameter, each surrounded by a film of organic material. This ice slurry acts as the phase change material (PCM), resulting in a massive increase of the surface area over which the thermal transfer takes place. The thermal battery has very high discharge rates, unlike solid ice technologies, and unlimited charge-discharge cycles with zero battery degradation.

The system’s cloud-based optimisation engine ensures peak savings in electricity and carbon. The battery is charged using off-peak electricity, or locally generated renewable power, and then drawn down for use during high-tariff periods. Time of use (ToU) shifting is one of the scalable control strategies which allow integration with existing systems and live external data, enabling chiller optimisation and high and low heat grade heat recovery.

In addition to accessing electricity at its cheapest, the optimisation engine also enables the system to take advantage of periods of low carbon intensity on the grid, when more of the power is produced from renewable sources, resulting in reduced impact on the environment.

Operating data from the trial reveals that EnergiVault will handle 30% of the Quotient Sciences site's 500MWh per year cooling demand at a basic level of operation, utilising ToU shifting to avoid high electrical tariffs. This has resulted in a 27% cost saving to date through load shifting and chiller efficiency benefits. When operating at its full potential, O-Hx calculates that savings significantly in excess of this will be available for the majority of sites, with potential for more than 60% saving against site cooling costs and reduction of CO2 emissions.

The site has also benefitted from the system back-up provided by EnergiVault during an existing chiller failure and planned shutdown for maintenance, either of which would otherwise have resulted in production disruption.

Stuart Munro, Head of Facilities, Quotient Sciences (Alnwick) said: “We are committed to reducing our carbon footprint and energy consumption at every opportunity. It is innovations such as EnergiVault and engineers committed to change that our planet needs now.

“O-Hx has been extremely professional, taking its proof-of-concept to a working unit that is now helping to support our site cooling needs. We are delighted to be involved in supporting this project.’’

Guests were able to examine the installed system, with live dashboard feeds demonstrating charge and discharge rates, energy consumption and further key data sets. They were also challenged to test the cooling capabilities of the ice slurry.

Presentations were made by members of the O-Hx team, Bitzer UK Sales director James Graham, and Miranda Barker OBE, CEO of East Lancashire Chamber of Commerce.

O-Hx executive chairman Bob Long said: “We have been delighted with the success of our working trials at Quotient Sciences and are proud to be able to share the results to date with a wider industry audience.

“We believe that energy storage for cooling can be one of the most effective methods of offsetting the effects on the environment of high loads during peak energy periods. This open day was an important step in the EnergiVault journey.’’