In the IEA Energy Storage TCP Task 44 Hi C Best about heat integrated Carnot batteries a subtask is focusing on finding the most fitting Carnot Battery for different industrial applications. The subtask leader DI Gerald Zotter and his team were hosting the latest Task 44 Expert Meeting in Graz, Austria.

 By Julie Søgaard  

Gerald Zotter has worked in the energy supply sector for 25 years, with a focus over the past 15 years on high-temperature heat pump development and thermal energy storage. Today, he is the Head of unit Thermal Energy Storages at AEE – Institute for Sustainable Technologies (AEE INTEC) in Austria. AEE INTEC is an independent non-university research center focusing mostly on heat supply for buildings, districts, cities and industry.

“In our research group we currently have three Carnot battery research projects with completely different topics, because there are many different application needs and different kinds of Carnot batteries. So, now we are working with bigger and high temperatures units as well as with smaller Carnot batteries,” Gerald Zotter explains.

Demand for process heat supply

In the IEA Energy Storage TCP Task 44 Hi C Best about heat integrated Carnot batteries Gerald Zotter is leading the subtask on identifying industrial applications for Carnot Batteries.

“When it comes to applications, even though the technical readiness level of some Carnot batteries is already high, the market is in the early stage of maturity. Therefore, we cannot simply point out what is already in the market. So, we focus more on what are the customer’s actual needs,” Gerald Zotter says.

Here, the subtask looks at district heating grids, electricity grids and smaller industrial facilities and plants.

“There is a big trend, especially in Europe, to step out of natural gas. Many business facilities have already installed a large number of photovoltaic panels, which give at surplus of energy during the weekends, when the facility is closed. So, they are now asking for storage in order to use the energy surplus on weekdays,” Gerald Zotter says.

Especially process heat supply is in demand in very different industries from food producers and breweries to the steel industry.

“We try to cluster end users by industry sectors, grouping them according to their demands, temperature levels, required process heat and cooling fluids, and temporal behaviour. This is key for designing storage systems in general, and Carnot batteries in particular,” Gerald Zotter says.

Matrix is matching Carnot Batteries with applications

Based on this information and how much the customers are willing to pay for the subtask works on making a list of applications fitting their specific needs.

“It will be like a matrix where we merge what we know from the customers side with the technology side. So, for a specific application a certain kind of Carnot Battery may fit better. Besides economic aspects, we are also looking at ecological benefits, such as avoiding CO₂ emissions and rare-earth metals, as well as using PFAS-free working media etc.,” Gerald Zotter says.

He hopes there will be a new IEA TCP task following up on this work with a closer collaboration between customers and technology providers.

The latest Expert Meeting in Task 44 was in Graz, Austria in April hosted by Gerald Zotter and his team. The next meeting will be in Stuttgart, Germany in October, where Gerald Zotter expects there will be a deeper focus on industry data and the application analysis.