Chilled water vs EnergiVault comparison

Comparison of EnergiVault, Chilled Water and Solid Ice Storage

EnergiVault is a hybrid chilled water/ ice storage system with the benefits
of both chilled water and ice storage and none of the limitations.

Cooling Flexibility
EnergiVault is better than competing storage options

Cold thermal energy storage allows chillers to realise full energy and carbon saving potential. EnergiVault® overcomes the limitations of other approaches to cold energy storage.

Solid Ice Storage

- Poor discharge capacity

- Low energy flexibility

- Poor responsiveness to sudden cooling demand

- Inefficient charging

Chilled Water Storage

- Poor temperature control

- Low energy density

- > 8x volume and higher footprint

Electrical Energy Storage

- High capital cost

- Limited lifecycles

- Degradation over time

- Low real turnaround efficiency

- High-capacity connection

- Storage without connected generation (Fault - Level) contribution; can add more generation instead

EnergiVault® Thermal Battery

- Easy Integration with renewables to reduce energy and Co2

- High peak cooling versus input power

- Ultrafast response to cooling demand

- No lifetime degradation

- >20- year lifetime

- Highly scalable

- Low footprint

Let's take a look at how the EnergiVault compares to chilled water or ice storage.

It can respond rapidly to changes in cooling demand, deliver short duration, high cooling rates compared to ice storage and delivers the chilled water cooling at constant temperature at one eighth the volume of equivalent chilled water systems. The constant lower temperature reduces pump power compared to chilled water providing further savings.

Chilled water systems require 8x the volume of an equivalent Energivault system

Facilities managers and HVAC engineers are constantly searching for ways of reducing energy costs and carbon emissions through load shifting, load levelling and integration with on-site renewables.

A commonly used solution is chilled water storage, less common is solid ice storage.

Both these “cool storage” approaches can provide energy cost savings, reduce peak time non commodity costs such as transmission and distribution charges, provide peak cooling capacity and optimise on-site renewable generation, all in addition to back-up cooling for added resilience.

EnergiVault delivers chilled water at constant temperature

However, both chilled water and solid ice storage systems have limitations which make them unattractive in many applications.

Chilled water systems are typically very large requiring huge volumes of chilled water with associated high chemical additive costs such as biocide and glycol. As the cooling comes from absorbing heat from the demand, the chilled water increases in temperature and returns to the storage tank, slowly increasing the storage temperature.

Solid ice storage has greater energy density than chilled water storage as it stores energy in the phase change between water and ice, however, the solid block of ice has limitations on cooling rates due to its limited surface are and therefore is not well suited to rapid cooling demands and responding quickly to short duration peaks, without being significantly oversized.