Recent Advances in Integrated Building Cavities: A Comprehensive Review of Fundamentals, Modeling, and Performance Evaluation

Currently, building envelopes are evolving from simple passive shields to smart systems. They control the exchange of energy, air, and moisture within the cavities of buildings. This comprehensive review attempts to investigate the potential performance outcomes resulting from the integration of photovoltaic/thermal systems (PV/Ts), phase change materials (PCMs), and heat pumps (HPs). After the screening process, 153 documents were selected to be synthesized, including 64 primary peer-reviewed publications, 20 standards, and 69 reviews or methodological articles. The results from experimental, field, and numerical studies have shown that cavity integration techniques are effective in achieving photovoltaic cooling, recovering useful heat, reducing heat flux, and supporting heat pump operation. Specifically, annual simulations showed a 6.5% reduction in heating electricity and coefficient of performance (COP) improvements of 22–26%, whereas short-term experiments reported COP gains of 3.3% on average and up to 8.6%. Hybrid (solar/thermal and waste heat recovery) system studies reported that combined heating and cooling energy can be saved by more than 50%. Yet, these results substantially varied with climate, cavity configuration, baseline system, control strategy, averaging period, and auxiliary energy usage. In general, PCM-integrated ventilated cavities can reduce summer heat gains while supporting controlled heat storage and release. However, in extreme weather conditions, application of PCMs may not be effective since complete phase transitions cannot be achieved. Therefore, future studies are recommended to focus on climate-responsive designs, validated hygrothermal models and controls, regulatory compliance, and life-cycle assessments.