Design and optimization of Heat Exchanger Networks is encountered as an important task when designing an industrial process. This is due to the energy crisis in the past three decades as well as the importance of environmental protection in achieving sustainable development. Heat Exchanger Networks comprising either mixed materials of construction, different exchanger types, or exchangers with different pressure ratings are considered to be more complicated in terms of targeting and design procedures. In this article a new method has been introduced, which takes advantage of Total Decomposition (as a known technique) and Partial Decomposition that is new and developed in this research. Also, Total Annualized Cost is minimized by optimizing AT of the network. Having used this technique, design will not anymore suffer from the increase in utility consumption that was due to heat recovery reduction between the sub-networks. The new method has been applied to a popular case study, using different utility and exchanger cost laws and also various interest rates and plant life times. Comparison of the results with other methods shows a reasonable improvement in both Western and Middle Eastern countries.
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