ABSTRACT
HVAC systems consume up to 50% of the total energy demanded by buildings. This paper aims to provide quantitative assessment of the HVAC solutions used on the highly efficient houses competing in the Solar Decathlon Middle East 2021. This international competition challenges university students to design, build, and operate sustainable zero-energy houses. The analysis includes the system selection, capacity, and coefficient of performance (COP), as well as the monitored indoor temperature, relative humidity, and CO2 levels. The university teams' selection capacity (systems availability) and budget were affected by the COVID-19 pandemic. However, they designed their houses to respond appropriately to arid climates and reduce HVAC consumption. The study evaluates the HVAC solutions of all eight projects, providing more information about the four top-ranked teams. Most homes use air-to-air, decentralized, and multizone air-conditioners. The teams made the best effort to select systems that significantly exceed the COP required by the local regulations. Some also exceed the local energy codes regarding refrigerants' global warming potential. The average COP (at T1 i.e., Moderate Climate Conditions) of air-to-air systems was 3.71 kW/kW, and the air-to-water system was 3.42 kW/kW. The lower installed cooling capacity per area of air-to-water HVAC systems was 57 W/m2 and 122 W/m2 in the air-to-air ones. In several cases, the HVAC systems' consumption was affected by the short assembly period (15 days), nonprofessional student construction, and the lack of a testing period before starting the competition. Nevertheless, these houses exhibited excellent performance, and their analysis brought relevant lessons for buildings in arid climates.
ABSTRACT
The COVID-19 epidemic increases the uncertainty of energy demand. This paper aims to study the impact of containment measures due to the COVID-19 epidemic on the energy demand of a group of buildings in a neighborhood and evaluate the different techniques studied on thermal performance and energy savings. Indeed, this study shows the importance of using natural and recycled waste-based materials and nighttime radiative cooling during the summer period. For this purpose, a full-scale cell located in Casablanca was considered a case study to build a simulation model performed on TRNSYS, validated using the experimental results. This model is then used to impact the techniques studied on energy performance and hours of discomfort inside another cell in Marrakech. As a result, this study has shown that the passive techniques integrated into the cell, using the material based on sisal/wool nonwoven, and night-time radiative cooling during summer, reduce energy requirements compared to the reference configuration. © 2022 IEEE.
ABSTRACT
Building energy codes are considered to be an effective policy tool for energy reduction worldwide. However, their application and effectiveness are still limited in developing countries. In Egypt, the residential sector is promising for energy savings, as most of the existing residential buildings are aged with low thermal performance and non-conformance with energy codes. This study aims to raise the awareness of promoting the Egyptian residential energy codes among construction parties, especially end-users, by quantifying the environmental impacts, in terms of energy savings and thermal comfort enhancement. Moreover, it attempts achieving a nearly zero energy building by integrating several energy-efficient measures with renewable energy sources. Thus, in this study, a typical residential building in Cairo was chosen for simulation. The simulation results revealed that applying energy code instructions for building envelope, lighting enhancement and increases in cooling set-points, from 24 °C to 25 °C, saved 37.85% of annual electrical energy and resulted in a cooling reduction of 50.53%. Furthermore, the photovoltaic system incorporation succeeded in transforming the building into a nearly zero energy building. Concerning thermal comfort, the application of passive energy-efficient measures significantly influences indoor thermal comfort, with a 30% reduction in discomfort hours during the cooling season, which represents the main concern in hot climate regions.
ABSTRACT
The COVID-19 pandemic has significantly impacted the global lifestyle, and the spreading of the virus is unprecedented. This study is aimed at assessing the association between the meteorological indicators such as air temperature (°C), relative humidity (%), wind speed (w/s), solar radiation, and PM2.5 with the COVID-19 infected cases in the hot, arid climate of Bahrain. Kendall and Spearman rank correlation coefficients and quantile on quantile regression were used as main econometric analysis to determine the degree of the relationship between related variables. The dataset analysis was performed from 05 April 2020, to 10 January 2021. The empirical findings indicate that the air temperature, humidity, solar radiation, wind speed indicators, and PM2.5 have a significant association with the COVID-19 newly infected cases. The current study findings allow us to suggest that Bahrain's relatively successful response to neighboring GULF economies can be attributed to the successful environmental reforms and significant upgrades to the health care facilities. We further report that a long-term empirical analysis between meteorological factors and respiratory illness threats will provide useful policy measures against future outbreaks.