Abraham Yezioro

Thermal mass and night ventilation as passive cooling design strategy

We calculated the influence of thermal mass and night ventilation on the maximum indoor temperature in summer. The results for different locations in the hot humid climate of Israel are presented and analyzed. The maximum indoor temperature depends linearly on the temperature difference between day and night at the site. The fit can be applied as a tool to predict from the temperature swing of the location the maximum indoor temperature decrease due to the thermal mass and night ventilation. Consequently, the fit can be implemented as a simple design tool to present the reduction in indoor temperature due to the amount of the thermal mass and the rate of night ventilation, without using an hourly simulation model. Moreover, this design tool is able to provide for the designer in the early design stages the conditions when night ventilation and thermal mass are effective as passive cooling design strategy.

Shading: A design tool for analyzing mutual shading between buildings

Abstract A method and a model for analyzing visually and quantitatively mutual shading between buildings is presented. The method allows fast and efficient calculation of the ratio between insolated and total surface areas of any given examined object that is shaded by other irregular and nonplanar elements. The calculation of this ratio is carried out for all the months and hours for which either shading or insolation is required. The information obtained may serve as hourly input data for any dynamic simulation model which evaluates the thermal performance of the different external or internal shading systems. For a visual and a qualitative evaluation of the shadows among buildings, the suggested model permits a very realistic representation, in which the light source is defined according to the azimuth and the altitude of the sun at the particular time of examination. The self shading and brightness of the different surfaces and the shadows cast by the different elements at the designated time are then generated and can be evaluated visually. The method is demonstrated by a case study.

Climatic aspects in urban design—a case study

We present a case study of a design of a new business district in Tel Aviv city. In this work climatic aspects were taken into consideration in the very early design stages. For that purpose, two models SustArc (Proceedings of the ISES 1997 Solar World Congress, Taejon, Korea, 1997, p. 148) and FLUENT 5.0.2 (Fluents Users Guide, Fluent Inc., NH, USA, 1999) were applied in order to achieve solar and wind rights. The new business district was designed as a high-density urban area and is located near an old low-rise residential quarter. SustArc was used as a design tool to create the solar envelope that shows the maximum available volume in which it is possible to build without violating the solar rights of existing residential neighborhood, the main avenues and the pedestrian sidewalks. FLUENT, on the other hand, was implemented as an evaluative tool, in a trial and error method, until a design solution could be achieved, in which the wind rights of the residential neighborhood were preserved, while ensuring tolerable winds inside the business district. The paper presents the process of sun and wind controlled planning, as well as the recommendations.

Analyzing mutual shading among buildings

A method for evaluating solar rights and shading requirements in an urban environment is presented. The method is embedded in a CAD tool developed and adapted for this purpose. With this tool one can analyze the mutual shading between buildings and other objects like trees. The purpose of this CAD tool is to allow the designer to plan efficiently the various functions of spaces among different structures, like buildings, as well as determining the location of the passive and active solar collectors. The method is a general one and allows a fast and efficient calculation of the ratio between insolated and total surface areas of any given examined object that is shaded by other irregular and nonplanar elements. The calculation of this ratio is carried out for all the months and hours for which either shading or insolation is required. The information obtained may serve as hourly input data for any dynamic simulation model which evaluates the thermal performance of the different external or internal shading systems. For a visual and a qualitative evaluation of the shadows among buildings, the suggested model permits a very realistic representation, in which the light source is defined according to the azimuth and the altitude of the Sun at the particular time of examination. The self shading and brightness of the different surfaces and the shadows cast by the various elements at the designated time are then generated and can be evaluated visually.

Simulations and knowledge-based computer-aided architectural design (CAAD) systems for passive and low energy architecture

Abstract This paper describes a methodology for supporting computationally all phases of an energy-conscious design and evaluation process, by combining procedural simulation and knowledge-based heuristic methods in one integrated system. Based on this methodology knowledge-based computer-aided architectural design systems for the design and evaluation of solar and low-energy buildings are presented. The knowledge-base contains the heuristic rules for the design of passive solar buildings. Whenever possible, the knowledge-base guides the designer through the decision-making process. Yet, if the rules of thumb are not acceptable for the particular design problem, the knowledge-based system guides the architect by using procedural simulation models.

What are the required conditions for heavy structure buildings to be thermally effective in a hot humid climate

We calculate the influence of thermal mass and night ventilation on the reduction of the maximum indoor temperature in summer in residential buildings without using air-conditioning. The results are given for different locations in the hot-humid Mediterranean climate of Israel. We found that the maximum obtained indoor temperature reduction depends linearly on the temperature difference between day and night at the site. The results obtained show that one can predict the indoor temperature decrease, due to the thermal mass and night ventilation, from the simple and available data of the long term average temperature swing of the site, which is a common available data. The conclusion is that in the hot-humid climate of the Mediterranean coast, high thermal mass with night ventilation is effective for residential buildings with no air-conditioning provided the temperature swing is above 5°C, which is in general the case in this climate.

A knowledge based CAAD system for determining thermal comfort design strategies

A computer-aided design system for determining thermal comfort design strategies is presented. The system is based on a knowledge base which stores the existing information concerning thermal comfort rules of thumb, and precise procedural calculations which facilitates the defining of thermal comfort design strategies that best suite the local climatic conditions and the specific constrains of the design problem at hand.

Non-Linear Architectural Design Process

The introduction of the computer to the architectural design process have facilitated the possibility to examine a large number of design alternatives by allowing continuous variation between pre defined constraints. However, for the most part, evaluation and comparison of the alternatives is still handled manually in a linear fashion by the designer. This paper introduces a different approach to the architectural design process, which calls for a multithreaded or a non-linear design process. In a non-linear design process design directions and alternatives are generated, presented and evaluated simultaneously, and in real time. As an example for a non-linear design process the Generative Performance Oriented Design model and software tool (GenPOD) are presented and discussed. Moving towards non-linear modes of design arguably increases design creativity by allowing generating and evaluating a greater number and variation of design alternatives.

Computer-Based Form Generation in Architectural Design - a Critical Review

The idea of using computers for form generation and evaluation in the architectural design process has been put forward already in the early days of computers. However, as opposed to computer aided drafting, the generation of form, its optimization and manufacturing has not been widely accepted and implemented by practitioners. The paper critically reviews the research and state of the practice experiments that has been done in this field and develops an argument regarding the possibilities and limitations of computer-based form generation in the architectural design process.

Conceptual Design: An Operational Prescription for a Computer Support System

A prescription for a computer based support system for conceptual design is presented. The necessary components needed are listed, and their implementation in a complete system is shown. Combining the components with the right balance among them is the key to a successful transition of todays conceptual design phase, using pencil and paper, to a computer based system. This work presents ConceptUdraft, a computer system built using this prescription. It allows the creative freedom of freehand 2D and 3D sketching the designer habitually relies on, assists that creative process and elevates it to a higher degree of visualization and interaction. The system developed may contribute to the quality of design and the speed with which conceptual design matures into a feasible new object.