Pipeline Modeling – Impact of Ambient Temperature and Heat Transfer Modeling

The impact of different methods for modelling heat transfer between a pipeline and the ambient is investigated. The differences in outlet temperatures between a steady and an unsteady heat transfer model are quantified, as well as the effects of simulating the annual oceanic temperature cycle over several years. A seasonal difference between measured and modeled outlet temperature is found. The results show that the absence of the heat storage term in the heat transfer model may only be a small contributing factor to this difference. Assuming the error is caused by inaccuracies in the ambient temperature, the impact on the capacity is found to be between 0.1 and 0.5 %.