A new approach is developed for targeting number of shells of a heat exchanger network, which directly accounts for the temperature cross. It is based on R and G values, where G is a dimensionless group defined to account the temperature cross. For this purpose design charts of F-T(R,S) and F-T(R,G) are developed and superimposed to create a single chart for each flow configuration. Here, R and S are two dimensionless groups called heat capacity flow rates and thermal effectiveness, respectively. In the present paper a chart for 1-2 shell and tube heat exchanger is shown. To show the reliability of this approach it is used to target number of shells for different heat exchanger network problems taken from open literature and the results are compared to that predicted from published methods. It is found that the present approach computes the number of shells with considerably less effort. (C) 2009 Elsevier Ltd. All rights reserved.