Carnot batteries are an emerging technology for base-load capable, electrical energy storage. During charging, the concept converts surplus electrical energy into thermal energy by means of a heat pump. During the discharge phase, a power cycle transforms the stored thermal energy back to electrical energy. Carnot batteries based on organic Rankine cycles rely on technically mature components and allow an effective integration of low-temperature heat sources to reach considerable efficiencies. However, thermally integrated Carnot batteries are stuck in a tradeoff between power-to-power efficiency, storage size and heat source utilization. This study suggests two approaches to minimize this trilemma. The first option targets at novel cycle layouts comprising flash cycles. Simulation results indicate that organic flash cycles with a two-phase expander increase the efficiency of Carnot batteries, particularly for high storage temperature spreads which enables more compact storages. The second option suggests Carnot batteries as highly integrated link between renewable power and district heating grids. That allows Carnot batteries to become a flexible sector coupling technology which can store and provide power and heat on demand.      «

Carnot batteries are an emerging technology for base-load capable, electrical energy storage. During charging, the concept converts surplus electrical energy into thermal energy by means of a heat pump. During the discharge phase, a power cycle transforms the stored thermal energy back to electrical energy. Carnot batteries based on organic Rankine cycles rely on technically mature components and allow an effective integration of low-temperature heat sources to reach considerable efficiencies. H...     »