Wojciech Marks

MULTICRITERIA OPTIMISATION OF SHAPE OF ENERGY-SAVING BUILDINGS

Abstract The object is to determine the optimum dimensions of the shape of a building of volume V and height h, based on the following criteria: (1) minimum building costs, including the cost of the materials and construction; (2) minimum yearly heating costs. The solution to the problem is presented in two ways. In the first, it is assumed that the shape of the plan of the building is defined by two arbitrary curves bounding the south and north faces and that the windows on the southern side are defined by a continuous function as a percentage of the total wall area. In the second, it is assumed that the building is of prismatic shape on polygonal plan, and using non-linear programming methods the proportions of wall lengths, wall angles and building height are determined. This problem was solved numerically by means of the CAMOS computer program. It is not the object of the paper to obtain a practical design. The results constitute information for designers on the optimum proportions of wall lengths, their angles and glazing parameters, taking into account the above-mentioned criteria. The degree to which these results can be applied in practice depends on many other requirements present in the design of buildings.

Optimization of shape and functional structure of buildings as well as heat source utilisation example

Abstract The purpose of this article is to present the method of solving the optimization problem of the internal partitions of the building, the shape of the building, as well as heat sources. The optimization of the internal partitions of the building is based on particular selection from the given list, and determination of the thickness of thermal insulation. Solving the problem of the shape has been solved first in order to determine approximately the building height, proportions of building sides and orientation of the building with respect to the north–south axis, as well as to check which of the inequality constraints are active in this case. Following this, after obtaining the results, it was checked whether replacing the rectangular plan of the building by a rectangle and two trapezoids is advantageous. The optimum choice of heat source types for heating for domestic use and the determination of share in covering the demand for heat in the time interval under consideration has been formulated and solved using continuous and discrete decision variables. Part-problems of the optimization are solved by analytical–numerical method. They consist of determining some decision variables using analytical methods and the remaining using numerical methods applying CAMOS computer system, original algorithms and programs. In optimization of heat sources, original numerical methods were used for the determination of the compromise set in case of discontinuous objective functions.

Optimization of shape and functional structure of buildings as well as heat source utilisation. Partial problems solution

Abstract The aim of the paper is to present rational methods of multicriteria optimization of the shape and structure of energy-saving buildings, as well as optimization of heat sources taking into account the energy criteria. Mathematical model describing heat losses and gains in a building during the heating season was selected and refined. It takes into consideration heat losses through walls, roof, floor and transparent partitions as well as heat gains due to insolation across transparent partitions. Particular attention was paid to a more detailed description of heat gains due to solar radiation, depending on the position of partitions relative to their north–south axis and the degree of their use. The problem of multicriteria optimization of individual homes and blocks of flats was formulated on the basis of the following criteria: • minimum construction costs, including cost of materials, erection, heating installations together with the cost of heat sources, • minimum seasonal demand of heating energy, • minimum of pollution emitted by heat sources installed in the building. The following were accepted as the global optimization criteria allowing to find the preferred solution: • minimum building construction costs and its running costs over N-years’ period together with minimum environment pollution during that period, • minimum distance from the point belonging to the compromise set to the ideal point. The method of solving the above formulated problem consists in decomposing it into three part-problems: • optimization of internal partitions of the building, • optimization of the shape of building, • optimization of heat sources. Part-problems must be co-ordinated subsequently.

Optimization of shape and functional structure of buildings as well as heat source utilization. Basic theory

Abstract The purpose of this paper was to illustrate the example of multicriteria optimization of the big blocks of flats. The method described in [Hwang and Masud (Multiple objective decision making—methods and applications—a state-of-art-survey. Lecture notes in economics and mathematical systems, Springer, Berlin, 1979)] and [Jendo and Marks (Archives of Civil Engineering 30(1) (1984))] is based on decomposition into part-problems: optimization of internal partitions of the building, the shape of building, heat sources, and finally adequate co-ordination of solutions. The above-mentioned co-ordination is obtained by an iterative method.

Multicriteria optimisation of the building arrangement with application of numerical simulation

This paper presents an example of the optimisation of two building arrangements as a function of three variables describing their alignment relative to each other and relative to North. The presented results are limited to the wind flow speeds around buildings in flat undeveloped terrain. The turbulence model K-ϵ has been adopted for this study. Calculations have been made with the use of simulation program FLUENT 4.3. The potential application of a multicriteria optimisation method for the selection process of the optimal arrangement of buildings which would provide required wind comfort has been investigated. Computer program CAMOS (Computer Aided Multicriterion Optimisation System) has been used for the optimisation procedure.

Multicriteria optimisation of polymer modified composites subjected to freezing and thawing cycles

Abstract The optimisation approach to any activity in technology, economics or other fields, is aimed at finding methods of determining the best solutions in an objective way. In particular, the optimisation of composite materials deals with problems of selecting the values of several variables which determine composition, microstructure, mixing procedure and curing regime, etc. This paper presents the application of the optimisation approach to the design of frost resistant concrete modified by two admixtures—methyl hydroxy ethyl cellulose, MHEC and polyvinyl acetate, PVA. Experimental data, including flexural and compressive strengths, total porosity and supercooling, all determined after 300 cycles of freezing and thawing was used for the formulation of the objective functions. The problem of optimisation was solved with the aid of the Computer Aided Multicriterion Optimisation System—CAMOS.

Multicriterion reliability-oriented optimization of structural systems by stochastic programming

Papers deals with multicriterion reliability-oriented optimization of truss structures by stochastic programming. Deterministic approach to structural optimization appears to be insufficient when loads acting upon a structure and material properties of the structure elements have a random nature. The aim of this paper is to show importance of random modelling of the structure and influence of random parameters on an optimal solution. Usually, quality of engineering structure design is considered in terms of displacements, total cost and reliability. Therefore, optimization problem has been formulated and then solved in order to show interaction between displacement and a total cost objective function. The examples of 4-bar and 25-bar truss structures illustrate our considerations. The results of optimization are presented in the form of diagrams.