29 March 2023
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The EnergiVault thermal battery has very high discharge rates and unlimited charge-discharge cycles
An innovative energy storage solution is ready to deliver cost savings for customers and support the global decarbonisation of cooling for industrial processes and commercial buildings.
The patented EnergiVault from Organic Heat Exchangers Ltd (O-HX) is now undergoing full trials following installation at a pharmaceutical facility in the north-east of England, where it has been integrated with an existing chilled water system.
The bolt-on cold thermal energy storage (CTES) system is said to add a range of capabilities to industrial and commercial chiller operation, including electrical load shedding and load shifting, use of on-site generated renewables and the capability to benefit from grid-level support payments. O-Hx calculates that by operating EnergiVault alongside an existing chiller installation, savings of up to 69% can be realised against site cooling costs, with up to 64% reduction of CO₂ emissions.
Bob Long, founder and executive chairman of O-Hx, said: “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. EnergiVault is designed to optimise energy usage for chillers in industrial and commercial applications, and provide peak load cover if required.
“It generally integrates with an existing chiller but can also provide cooling on its own. Incorporating energy storage into a cooling system can potentially reduce indirect emissions, as without storage equipment has to run to meet demand, even when conditions are not optimal.”
The EnergiVault charger converts heat transfer fluid into ice crystals
EnergiVault consists of a charger and thermal battery. The charger’s ice crystalliser charges the battery by converting up to 60% of the building's heat transfer fluid (HTF), typically a water/glycol mix, into spherical ice crystals a fraction of a mm 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 is an insulated container, available in capacities up to 1MWh capacity units which are fully modular to meet demand. It has very high discharge rates, unlike solid ice technologies, and unlimited charge-discharge cycles, with zero battery degradation.
Using the cloud-based optimisation engine ensures peak savings in electricity and carbon. The battery is 'charged' by the refrigeration system using off-peak electricity, or locally generated renewable power, and then drawn down for use during high-tariff periods. Time of Use shifting is one of EnergiVault’s scalable control strategies, which allow integration with existing systems and live external data, enabling chiller optimisation, high and low heat grade heat recovery and solar PV (local energy generation).
In addition to accessing electricity at its cheapest, the optimisation engine also enables EnergiVault 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.
O-Hx estimates a payback on investment of 1.8 years for EnergiVault when used alongside an existing chiller installation, or 1.5 years if bought instead of an additional chiller, once purchase, operation and maintenance costs are taken into account.
