The Problem

In the pursuit of fulfilling the Paris Agreement, the share of renewable energy in buildings must increase significantly to reach 77% by 2050, a substantial leap from the current 36% (IRENA, 2018). The challenge lies in achieving this exponential jump, particularly as photovoltaic panels are approaching their efficiency limit (the Shockley-Queisser limit of 33.7%), with the best commercial panels currently operating at 26.9%. To overcome this hurdle, embracing advanced technologies like multi-junction solar cells with an efficiency of 47.1% (NREL, 2025) becomes crucial to surpass the limitations of the Shockley-Queisser threshold. Furthermore, utilizing solar thermal collectors, which offer a typical efficiency of 70%, presents another alternative operating above the Shockley-Queisser threshold.

However, barriers such as the high cost of multi- junction solar cells and the limited application scope of solar thermal collectors due to low- grade heat pose challenges. Addressing this involves focusing on developing medium-high grade heatsolutions (100- 400ºC) in close proximity to buildings. Thisadvancement opens doors to integrating established processes like district heating, cooling, air conditioning, industrial heat applications, water desalination, and power generation directly into building infrastructures through innovative methods like ranking cycles and sterling engines.

By bridging this technological gap and enhancing heat capabilities, the potential for a holistic integration of diverse energy processes into buildings emerges, paving the way for a more sustainable and energy-efficient future.