Bitzer UK is collaborating with O-Hx Ltd on the development of that company’s pioneering coolth storage technology, EnergiVault, which uses high-efficiency Bitzer open-drive screw compressors to generate cooling that is stored in a 'coolth battery' based on phase change material (PCM).

EnergiVault, developed with the support of UK government funding, uses stored cooling energy to support peak demand when chillers are maxed-out, and to load-shift energy consumption to benefit from lower tariffs. Importantly, it can also be used to ensure continuity of cooling in the event of chiller breakdown, and as a buffer to smooth-out loads to reduce inefficient chiller cycling.

Kevin Glass, Managing Director of Bitzer UK, said: '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 it's 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.'

A 650kWh demonstration project installed at pharmaceutical specialist Quotient Sciences' facility in Alnwick last year has demonstrated EnergiVault’s effectiveness in delivering peak load support, energy resilience and reliability.

The project delivered significant savings in energy costs by charging the coolth battery with lower-cost overnight electricity and 'trickle-charging' to replace chiller cycling, as well as ensuring continuity of operations under high temperatures and humidity, when previously the existing system would have been overwhelmed.

Bob Long, executive chairman and founder of O-Hx, said: “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.'

Unlike lithium batteries, which can discharge only around 70% of their power, 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, for example, is highly efficient due to the inherent efficiency of the refrigerant and Bitzer screw compressors. Any conversion losses are comfortably exceeded by the savings achieved through using off-peak electricity.

Kevin Glass, managig director of Bitzer UK said: '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.'