The building sector is both a major contributor to climate change and one of the most exposed to its impacts, and dwellings designed today will operate under mid-century climates. This study quantifies the projected impact of climate change on the climate of Riyadh, Saudi Arabia, and on the thermal performance and comfort of a government-approved residential villa archetype, and tests envelope improvement as an adaptation measure. Future hourly weather files for 2061–2080 were generated from a baseline IWEC typical meteorological year by morphing with change factors from the CMIP5 ensemble (IPCC Fifth Assessment Report) under RCP 4.5, at the 10th, 50th, and 90th percentiles of the ensemble warming distribution. Relative to the baseline, summer means rise by 2.1–4.1 °C across this range, days with maxima of 45 °C or more increase from 5 to 40–74, tropical nights above 30 °C from 25 to 72–124, and cooling degree-days by 17–35%. Under the warm-end (90th percentile) file used for the IES Virtual Environment building simulations, living-room PPD rises from about 11% to 13% with wider cooling peaks, and raising wall and roof insulation to ASHRAE 90.1-2019 levels cuts envelope conduction gains by about 6% and energy use intensity from 128.42 to 123.45 kWh/m²·year (−3.9%). The findings support tightening envelope requirements in the Saudi Building Code and integrating future weather files into design practice.

Building regulations are one of the important tools that improve urban environment due totheir rules and standards which control the relationship between buildings within their urbanpattern. Riyadh city is characterized by it’s hot and dry climate, which requires compatibleclimatic treatment with its desert environment. The compact pattern of traditional buildings ofRiyadh constituted a good example of the compatibility and adaptation of the building with itssurrounding environment, starting from the layout of the building and ending by itsrelationship with the surrounding urban pattern. The changes in the size of the urbandevelopment has led to import building regulations from different environments that hasdifferent climate of Riyadh. As a result, the imported building regulations caused negativeimpacts to thermal performance of residential buildings in Riyadh and consequently theenergy consumption has witnessed a dramatic increase.The developed building regulation which was released in 2018, has made severalmodifications to the previous building regulation in terms of the rear and side setbacks ofbuilding’s first floor. So, it is of great importance to evaluate this building regulation toinvestigates its impacts on the thermal performance of buildings. The main aim of thisresearch is investigating the impacts of the developed building regulation on the thermalperformance of residential buildings in Riyadh.The methodology adopted for achieving the aim of this research consists of two phases. First,a literature review was conducted to investigate the development of urban growth andbuilding regulations in Riyadh. Second, residential buildings energy simulation was carriedout to examine the impacts of the developed building regulation on the thermal performanceresidential buildings. At the end, the study come up with some results and recommendationsthat will contribute to boost environmental aspects in buildings regulations and improveresidential building’s thermal performance in Riyadh city. تعدّ أنظمة البناء من الأدوات الأساسیة المؤثرة فی الارتقاء بمستوى البیئة العمرانیة لما تفرضھ من ضوابط ومعاییر تسھمفی تنظیم العمران، والتحکم فی العلاقة بین المبانی ضمن نسیجھا الحضری. تمتاز مدینة الریاض بمناخھا الحار الجاف،وھو ما یتطلب معالجات مناخیة تساعد فی تحقیق بیئة عمرانیة ملائمة لبیئتھا الصحراویة. وفی الماضی مثلّ النسیجالعمرانی المتضام للمبانی التقلیدیة، الذی کان سائدا فًی مدینة الریاض، نمطا رًائعا لًلتوافق والتأقلم مع الظروف البیئیة بدءاًبتصمیم المبنى منفردا وًانتھاءً بعلاقتھ مع النسیج العمرانی المحیط. وقد أدى التغیر فی حجم التنمیة العمرانیة إلى استیرادمجموعة من أنظمة البناء من بیئات مختلفة عن مدینة الریاض وبالتالی ظھور أنماط عمرانیة غیر...

Cooling keeps even well-designed Saudi solar houses dependent on the grid. This study asks whether open-loop ground-coupled ventilation (GCV) can move a net-zero-energy Solar Decathlon house in Riyadh towards carbon-free operation. The house was re-modeled in Revit, Carrier HAP and HelioScope and validated against the original design. A buried vitrified clay pipe (19.8 m, 0.30 m diameter, 6 m deep) was sized with a regression-based design tool and coupled hour by hour to the outdoor air required by ASHRAE 62.2 (20 L s⁻¹), with bypass control, calculated fan power and an hourly battery model. The pipe cooled the outdoor air by 4.8 K on average, yet saved only 2.8% of HVAC electricity (2.4% net of fan energy; 3.2% ahead of the house’s energy recovery exchanger), because ventilation is a small part of this envelope’s load; the saving reaches 32% only at 6.4 outdoor air changes per hour. Grid import (4961 kWh y⁻¹, mostly at night) fell by 2.2% with GCV, by 23% with evening loads shifted to midday, and to 50–64 kWh y⁻¹ with a 40 kWh battery and load shifting. The GCV has a negative net present value at current tariffs. Storage and demand scheduling, not cooling load, are the binding constraints.