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Sunamp: Heat Batteries

Decarbonising heat is the biggest challenge the UK faces in terms of transforming the energy system to meet Net Zero carbon targets – and innovation is crucial to that challenge.

Sunamp has developed groundbreaking compact ‘heat batteries’ that store thermal energy at times when renewable generation is plentiful and cheap to be used for heating at a later time on demand.

Energy Systems Catapult worked with Sunamp via the Energy Launchpad to assess the current market landscape, model how the technology can best be integrated into heating systems, assess the value for consumers, and refine the customer proposition.

The Innovation

Sunamp heat batteries use a patented phase change material that provide the residential market with a low carbon, reliable, space-saving thermal battery storage system.

With the emergence of dynamic time of use tariffs households will be able to cut carbon emissions and fuel costs by charging the battery with mains power at times when grid demand and cost is low or by using on-site renewable electricity- such as solar PV. The energy can then be released to deliver space heating, hot water and even cooling on demand across a wide range of temperatures.

Sunamp’s range of four battery sizes can be combined to create the right solution to perfectly match the exact heating requirements of a property – yet are four times smaller than equivalent hot water cylinders.

The company’s range of heat batteries for the residential market provide a low carbon, reliable, space-saving thermal battery.

The Challenge

Heating our homes and buildings is responsible for around 20% of UK carbon emissions. To achieve our 2050 Net Zero target, the UK’s 27 million households will need to rapidly adopt new low carbon heat solutions throughout the 2020s and 2030s.

There is a significant opportunity for thermal storage to provide one of those solutions, by shifting loads away from times of peak demand or by taking advantage of times of surplus renewable generation.

The challenge for Energy Systems Catapult was to help Sunamp identify which part of the residential market they should target through maximising the use of embedded electric generation in homes; to assess how their heat battery technology can best be integrated with heat pumps or existing gas heating systems; and to refine the customer value proposition.

Sunamp thermal batteries use a patented phase change material to store heat.

Sunamp thermal batteries use a patented phase change material to store heat.


Acceleration Support provides scale-up support for selected high-impact potential SMEs, including Business Model development and validation, Access to demonstration environments like the ‘Living Lab’, Engagement with potential corporate customers, Investment Readiness and Partnership, Access to International opportunities and Investment partners.

The Solution

Energy Launchpad helped Sunamp to determine the revenue streams associated with connecting their heat batteries directly to the grid and any embedded generation, in order to provide heating and hot water to households.

Andrew Bissell, CEO Sunamp Heat Batteries

“What I valued most was the surety of the results from the model – I didn’t have to put time in to examine or check the results. I trusted the results based on the Energy Systems Catapult staff we were working with – they came across as very solid and thorough.”

The Impact

Sunamp used the insights from the market analysis, BMI and consumer research to identify the most attractive market segments and the integrations and partnerships needed to be successful. HED modelling work provided the data to specify the optimal configuration and battery size by building and occupancy type. The Catapult’s independent verification enabled Sunamp to evidence to social housing providers the value of installing heat batteries in high rise dwellings.

Sunamp are now gaining traction in this market, having undertaken two product trials that led to confirmed sales, including their biggest single order to date.

Energy Systems Catapult’s support has helped Sunamp to progress the Technology Readiness Level of their product from 8 to 9.

Their new customer wins have helped to take their turnover from £3.5million to £5.4million.

Next Steps

The market analysis supported by the HED modelling has identified an opportunity in the private owner occupier market. Catapult recommendations on activities and partnerships to develop as part of Go-to-Market plan are being accelerated, enabling them to enter this market much faster than would have otherwise been possible.

With strong evidence of market need from the consumer insights work, Sunamp are adding resources to the marketing teams to support the sales activity.

And the firm is seeking further funding to support the cost of product certification.

Home Energy Dynamics

First-of-a-kind simulation tool for testing product performance before committing costs to real-world demonstration trials

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