Capital Cost Targeting of Total Site Heat Recovery

Exploiting heat recovery on Total Site level offers additional potential for energy saving through the central utility system. In the original Total Site Methodology (Klemes et al., 1997) a single uniform ΔTmin specification was used. It is unrealistic to expect uniform ΔTmin for heat exchange for all site processes and also between processes and the utility system. The current work deals with the evaluation of the capital cost for the generation and use of site utilities (e.g. steam, hot water, cooling water), which enables the evaluation of the trade-off between heat recovery and capital cost targets for Total Sites, thus allowing to set optimal ΔTmin values for the various processes. The procedure involves the construction of Total Site Profiles and Site Utility Composite Curves and the further identification of the various utility generation and use regions at the profile-utility interfaces. This is followed by the identification of the relevant Enthalpy Intervals in the Balanced Composite Curves. A preliminary result for evaluation of heat recovery rate and capital cost can be obtained.