While phase change material (PCM)-based thermal energy storage (TES) can help mitigate the intermittency of renewable energy, the system-level evaluation of standalone, macro-encapsulation PCM-TES devices remains challenging. Comparisons based on absolute performance data are affected by differences in device size, internal geometry, and operating conditions, making cross-study interpretation difficult. To address this gap, this review systematically applies established volume- and mass-normalized performance metrics to a curated dataset of standalone macro-scale PCM-TES devices. The contribution lies in this systematic device-level synthesis and its interpretation of capacity–rate trade-offs and comparison limits. Volume- and mass-normalized indicators reveal differences that are obscured by absolute capacity and rate, but do not eliminate scale effects. PCM type, TES configuration, operating temperature, and HTF are strongly associated in the compiled literature; consequently, observed performance differences cannot be attributed independently to PCM type. Heat transfer area enhancement and flow distribution provide physical explanations for configuration dependent performance, while the available direct-contact evidence remains limited. The review provides conditional guidance for comparing PCM-TES devices and identifies the measurements needed for more reproducible system-level evaluation.
