BITZER UK Collaborates with O-Hx Ltd on Innovative EnergiVault Coolth Storage Technology

There is growing interest in the potential of ‘coolth storage’ as industrial refrigeration users and building owners implement decarbonisation plans and seek to enhance energy resilience. BITZER UK is collaborating with O-Hx Ltd on the development of EnergiVault, a pioneering coolth storage technology that uses high-efficiency BITZER open-drive screw compressors to generate cooling stored in a 'coolth battery' based on phase change material (PCM).

EnergiVault Technology

EnergiVault, developed with UK government funding, utilizes stored cooling energy to support peak demand when chillers are maxed out and shifts energy consumption to benefit from lower tariffs. It can also ensure continuity of cooling during chiller breakdowns and act as a buffer to reduce inefficient chiller cycling.

Kevin Glass, Managing Director of BITZER UK, stated: "We have supported EnergiVault from day one, as we saw the potential of this innovative refrigeration-based power storage system as part of the drive to decarbonise and increase energy security." He added, "Following its successful pilot, the solution is now attracting a lot of interest – particularly from large industrial refrigeration users who want to protect production in the event of chiller failure, with the ability to add refrigeration capacity at peak load or to increase output."

Demonstration and Impact

A 650kWh demonstration project at Quotient Sciences' facility in Alnwick showcased EnergiVault’s effectiveness in providing peak load support, energy resilience, and reliability. The project significantly reduced energy costs by charging the coolth battery with lower-cost overnight electricity and using 'trickle-charging' to replace chiller cycling. It ensured continuous operation under high temperatures and humidity, conditions that previously would have overwhelmed the existing system.

Bob Long, Executive Chairman and founder of O-Hx, noted: “EnergiVault stepped in seamlessly during the high summer temperatures, delivering huge amounts of thermal energy when needed to support the site's struggling cooling equipment. EnergiVault combines the high energy-density found in block ice storage with the rapid and flexible discharge capability found with chilled water storage.” He added, “Work on system optimisation continues, and on the basis of the excellent results so far, our performance expectations have been exceeded. We are now following up several active enquiries for EnergiVault and pressing ahead with plans for full-scale commercialisation."

Advantages Over Traditional Batteries

Unlike lithium batteries, which can only discharge around 70% of their power without compromising the device, all the energy stored in an EnergiVault can be used without harming the device or its future storage capacity. The charging process, using ammonia refrigeration and BITZER screw compressors, is highly efficient due to the refrigerant’s inherent efficiency. Any conversion losses are outweighed by savings achieved through off-peak electricity usage.

Kevin Glass emphasized: "EnergiVault is an exciting development and demonstrates the potential of refrigeration-based power storage systems as transformational solutions. The push for net-zero carbon will require a complete rethinking of our energy infrastructure. With its thermodynamic and efficiency advantages, refrigeration offers the exciting prospect that our industry could be in the vanguard."

This collaboration underscores the ongoing efforts to improve energy efficiency and resilience in industrial refrigeration, contributing to broader sustainability and decarbonisation goals.