How Sunamp thermal batteries work

Based on the understanding that the world uses over twice as much heat as electricity, Sunamp thermal batteries help solve numerous problems by storing energy as heat and releasing it when and where it is needed.

Sunamp thermal batteries are energy-saving thermal stores containing Plentigrade: our high-performance phase change materials (PCMs) that deliver heating or cooling reliably, safely and efficiently.

Our innovative technology has resulted in a uniquely successful formula which is transforming how we use energy and provide heat around the world.

Super-compact thermal batteries

How it works

Storing heat and releasing it on demand

Optimising renewables

Our thermal batteries support the electrification of heat.

They work with heat pumps, wind and solar, grid and microgrid electricity, waste heat, combined heat and power (CHP) and boilers.

And store 4 to 10 times more energy than conventional materials.

Sustained with Plentigrade

Sunamp’s patented Plentigrade technology stores energy in our high-performance phase change materials and releases it to give hot water, heating or cooling on demand.

Long lifespan with best-in-class reliability rating.

Wide temperature range

Plentigrade discharges at a consistent, controlled temperature.

Reliably, safely and efficiently.

This means our thermal batteries can be used to freeze (-30°C), refrigerate (5°C) or warm (58°C), and even sterilise (118°C) in many different settings.

Making homes, buildings and industry more energy efficient and sustainable

Combining low-cost materials, exceptional long-life and recyclability, our energy-dense batteries deliver a low-carbon solution for freezing, cooling, heating, steam, and hot water.

How our Plentigrade P58 phase change material makes hot water


Plentigrade is the remarkable PCM inside our thermal batteries which absorbs and releases thermal energy during a melting and freezing process in a similar way to the gel in a pocket handwarmer.

  • PCMs absorb, store and release large amounts of latent heat when changing state between solid and liquid. Heat is absorbed on melting and released on freezing
  • Melting and freezing our Plentigrade P58 PCM formulation stores up to four times more energy than heating and cooling hot water
  • A high-powered heat exchanger or heating element immersed in our patented PCM rapidly charges the thermal battery. Heat is just as quickly extracted, and in our Thermino products, provides fresh, mains pressure hot water at a constant temperature only when it’s needed
  • Reliable, safe, non-toxic, non-flammable
  • Lowers energy use and carbon emissions