An Integrated Passive System to Optimize Thermal Comfort and Indoor Air Quality: A Case Study in Palestine’s Hot-Arid Climate

Abstract

The reintroduction of earthen architecture in Jericho, in the hot-arid Jordan Valley of Palestine, offers a low-energy alternative to conventional construction, yet the thermal and air-quality performance of Compressed Earth Block (CEB) buildings in this climate remains largely unquantified. This thesis evaluates an integrated passive system in which thermal mass, envelope design, ventilative cooling, and operational control are optimized together to deliver thermal comfort and indoor air quality during a representative summer design week. Combining field monitoring with a calibrated DesignBuilder model, the study follows a seven-phase optimization across three representative spaces, a daycare, an office, and a residence, assessed against the ASHRAE 55 adaptive comfort limit and the EN 16798-1 Category II criteria. The results characterize the earthen mass as a heat modulator rather than a heat rejecter: it damps the outdoor swing, holding the indoor air temperature to a daily range of about 2 °C against 11 to 14 °C outdoors, but underperforms wherever a dominant load, an exposed roof or unshaded glazing, enters continuously. This yields a load-sequencing principle, in which the dominant load is mitigated first and the mass then modulates what remains. A 29.5 cm CEB wall with 5 cm of exterior insulation on all external walls carries most of the available damping, while a reflective roof and reduced glazing address the governing solar and roof loads. A climate-responsive control framework governs operation on three signals, outdoor temperature, occupancy, and indoor operative temperature, deploying cross-ventilation as the primary mode, night flushing where continuous occupancy allows, and direct evaporative cooling through the hot, dry afternoon. Under this framework, the integrated system kept all occupied hours below the 80% comfort limit, with mean operative temperatures of 28.2–29.1 °C and CO2 concentrations of 693–1207 ppm, within EN 16798-1 limits. Compared with conventional cavity-brick and stone-clad walls, the optimized earthen envelope achieves comfort with fewer interventions. The framework holds comfort and air quality by passive, low-energy means, reducing to a fixed schedule occupants can operate by hand.