Mohamed B. Gadi

Design and simulation of a new energy-conscious system (CFD and solar simulation)

This paper presents the use of a validated CFD programme (FLUENT) and a solar simulator, for designing a solar water-heater. The water-heater is part of a new passive cooling and heating system introduced for buildings in North Africa. CFD transient simulations were carried out using a small time-step of 10 s and a set of fine body-fitted computational grids (1770-4740 nodes). FLUENT results were then verified against indoor testing employing a solar simulator. Good agreement was achieved.

Design and simulation of a new energy conscious system, (ventilation and thermal performance simulation)

This paper presents the results of simulating the ventilation and thermal performance of a new passive cooling and heating system. The new system was integrated into the roof of a typical contemporary North African house, which was modelled and mounted inside a wind tunnel, for natural ventilation simulation. Thermal performance of the new system was simulated using a new computer programme (BTS), developed by the author. Results are presented in terms of indoor temperature and CATD and HATD, which are newly introduced concepts in defining the building cooling and heating loads.

A new computer program for the prediction and analysis of human thermal comfort

This paper describes a new computer program, which was written for the prediction and analysis of human thermal comfort. The program incorporates six thermal comfort indices; three original and three modified versions of the original. The original indices are; Fangers Comfort Equation, Sharmas Tropical Summer Index and Madsens Equivalent temperature. Results produced by the program are presented in terms of the same PMV scale (Predicted Mean Vote). The six indices are, however, classified as three for summer and three for winter.

Effect of Integrating Wind Catchers with Curved Roofs on Natural Ventilation Performance in Buildings

Abstract In an investigation into wind-induced natural ventilation performance in buildings, this study uses Computational Fluid Dynamics to examine the effect of integrating wind catchers with curved roofs, implementing three-dimensional modelling. It is intended to give more value to the symbolic role of the dome, vault and tower in architectural design. The early findings of this study revealed that curved roofs induce natural ventilation in buildings by suction. This is generally true for the central and upstream zones of deep-plan buildings, but not for the downstream zone. Thus, wind catchers can be used to overcome this problem. This has been investigated by considering different geometrical and climatic parameters. The results show that the proposed ventilation system increases airflow rates and improves internal airflow distribution.

Using CFD to Investigate Ventilation Characteristics of Domes as Wind-Inducing Devices in Buildings

Many traditional architectural elements are still used in contemporary architecture. One way to give their existence more value is to use to serve design sustainability. Using CFD three-dimensional simulation, this paper investigates the effect of domed roofs on wind-induced natural ventilation performance, considering different building forms and areas, and different wind directions and velocities. Natural ventilation performance has been assessed in terms of airflow rate and internal airflow distribution. Results showed that domes improve ventilation performance in the upstream and central zones of the building, as suction forces acting over them induce more inflow rate through the building and attract some of the outflow to leave through dome openings instead of walls openings.

Design and simulation of a new energy conscious system, (basic concept)

A new passive cooling and heating system is introduced in this paper. The system was designed to be adaptively, integrated into the fabric and layout of buildings in North Africa. After discussion of the passive thermal design principles, a number of traditional and modern passive cooling and heating strategies are reviewed and analysed. Lessons learned from these examples have greatly helped design the new system. Development of the new system was based on both architectural design and principles of building engineering.

A novel roof-integrated cooling and heating system

SYNOPSIS From a review of a number of vernacular and modern environmental solutions and a study of local climatic, social and economic features in North Africa, a new design of roof system is developed. The new system is designed for inducing natural ventilation and cooling in summer and provision of heating in winter. It incorporates a transparent dome and a pitched thermal storage roof. In summer natural air movement is promoted by wind action on the dome apex while the thermal storage roof is used as a heat sink for space cooling. In winter, solar radiation absorbed by the pitched roof components is radiated to the space below in the form of thermal energy. The natural ventilation performance of the new system is investigated using a scale model mounted inside a boundary layer wind tunnel. Development of the thermal storage roof components is carried-out within a Computational Fluid Dynamics software (FLUENT) developed by Fluent Inc. Verification of the computer results is undertaken using real sized models of the pitched roof components and a solar simulator.

Effect of slope angle on energy performance of ground-integrated buildings on slope terrain

The noticeable rise in urban development and topography factors across Europe has resulted in a visible increase in the number of residential buildings being constructed in hillside areas. Several studies about ground-integrated architecture have proved that buildings can benefit from ground thermal potential, in order to reduce or eliminate the heating and cooling needs. However, only a small number of published articles tackle the potential of ground-integrated buildings on sloped terrains. The purpose of this paper is to explore the ground thermal potential of sloped terrains in temperate climates, through parametric studies using EnergyPlus as the energy modelling software. This paper looks at two main questions: firstly, how buildings are affected by terrain inclination and, secondly, which types of slope building designs are more thermally efficient, particularly the case of spilt level, amended section and cascade or step-hill designs.

New computerised tools for building design in different climates

SYNOPSIS The present paper describes two new computer programs, BTS and COMFORT. The first was written to help simulate the performance of a new passive cooling and heating system, designed by the author for buildings in North Africa. BTS is based on a simplified version of the admittance method. The main algorithms empolyed in the program are presented. Finally a validation proceedure was applied against an independent full scale experiment. Good agreement was obtained. The second program was written for the prediction and analysis of human thermal comfort. The program incorporates six thermal comfort indices; three original and three modified versions of the original. The original indices are: Fangers Comfort Equation, Charmas Tropical Summer Index and Madsens Equivalent Temperature. Results produced by the program are presented, for the six indices, in terms of the same Predicted Mean Vote, (PMV scale). The six indices are, however, classified as three for summer and three for winter.

Toward sustainable school building design: A case study in hot and humid climate

Abstract There is a global concern about energy in buildings generally for two major reasons. The first one is to minimise the energy consumption in buildings, while the other is to provide thermally comfortable buildings with minimum energy usage. Most of the work carried out in buildings was in office as well as domestic sector. However, the limited publication was done in educational buildings generally. The significance of this research is to take into consideration the energy pattern in a school building in the Kingdom of Saudi Arabia. The research is going to use TAS EDSL computer modelling with its validation. TAS is one of the most commonly used software globally to predict energy building performance. In addition to that, the school will be visited for monitoring. Several types of advanced tools will be used to measure indoor air temperature, relative humidity and much more. This investigation shows that the utilisation of natural ventilation has a major impact on internal temperatures. It has lowered the minimum by 6°C and also lowered the maximum by 3°C. In addition to that, there is a noticeable influence on the top classroom which has its roof exposed to the outdoors. Such outcomes can serve the new vision of Saudi Arabia 2030 and aid to improve the reliance of its buildings on energy.