This paper presents a systematic method for synthesis of heat exchanger networks, the proposed algorithm consists of three sequential steps to select the optimal approach temperature: i) Estimation of normalized minimum approach temperature, normalized minimum hot utility and normalized minimum cold utility. ii) Fuzzy analogical gates network. iii) Selection of the best weight index. Two analogical gates (symmetric and asymmetric) are employed. The symmetric gate (AND gate) inputs are the normalized minimum approach temperature and normalized hot utility. The asymmetric gate (Invoke gate) inputs are the output of the AND gate and the normalized cold utility. The proposed method has been applied for four problems well-known in published literature. The results of these case studies show that the present strategy is both robust and accurate in finding out global optimum in comparison with previous works, characterized by its simplicity and can be implemented by hand calculations.

This paper presents a new strategy to synthesis optimum controllable heat exchanger networks; the proposed strategy consists of four sequential steps: i) Quantification of index of structural controllability. ii) Exergy analysis and normalized irreversibility. iii) Thermal effectiveness of network. iv) Fuzzy analogical gates network and selection of the best weight index. Two analogical gates (symmetric and asymmetric) are employed. The symmetric gate (AND gate) inputs are the index controllability and thermal effectiveness. The asymmetric gate (Invoke gate) inputs are the output of the AND gate and the normalized irreversibility. The proposed method has been applied for two problems well-known in published literature. The results of these case studies show that the present strategy is both robust and accurate when the index of controllability is the same for different networks and it's to hard to decide the optimum controllable network, also, from the view point of exergy and thermal effectiveness.

This paper presents a new technique to synthesis optimum heat integration networks between areas; the algorithm followed for heat recovery problems begins by establishing the minimum energy requirement. For a given network energy consumption, deficit cascades and zone problem table is used to evaluate the minimum number of heat exchanger units. Various network structures may be generated simultaneously to achieve the energy and range targeting. The energy saving and area added are then calculated for different alternative distribution cascades with respect to MER also the number of interzonal transfer .The resulting networks are then subject to fuzzy analogical gates which consists of two analogical gates (symmetric and asymmetric). The symmetric gate (AND gate) inputs are normalized savings in energy requirement and the number of inter-zonal transfer. The asymmetric gate (Invoke gate) inputs are the output of the AND gate and normalized added area. The proposed technique has been applied for the popular and well-known aromatic problem. The results of this case study show that the present strategy is excellent in decision making for the optimum area target and very good indicator to the optimum sequence for alternative distribution cascades compared to total network costs, also robust, accurate and time saver when there are a large number of alternatives possibilities.

In this paper a new systematic method for optimal synthesis of heat integrated distillation column has been developed, the proposed method which is fuzzy analogical gates consists of three sequential steps to select the best separation sequence: estimation of the normalized variables parameters, Fuzzy analogical gates and selection of the best split, Two analogical gates (symmetric and asymmetric) are employed. The symmetric gate (AND gate) inputs are the normalized heat load, normalized column temperature difference. The asymmetric gate (Invoke gate) inputs are the output of the AND gate and the normalized (Q.∆T). The method has been tested for three problems reported in the literature which have been solved previously using other approaches.

A systematic method for synthesis of heat exchanger networks by using fuzzy approach is presented in this paper, the proposed method consists of three sequential steps to select the optimal approach temperature: i) estimation of minimum approach temperature, minimum hot utility and minimum cold utility. ii) Fuzzy approach. iii) Selection of the best weight index. The proposed method has been applied for two problems well-known in published literature. The results of these case studies show that the present strategy is simple and accurate in finding out global optimum in comparison with previous works, characterized by its simplicity and can be implemented by hand calculations.