D5.2 Report on maintenance effects of flexibility installed in demosites

The basic ideas of the Flexi-Sync project are to utilize more renewable energy and to optimize the income of sales of energy and the costs of producing and distributing the energy by means of introducing more flexibility. One of the means can be price models for utilizing a beneficial customer behaviour without an increase of the general energy price level. Furthermore, the energy companies can moderate the production of power and heat to get a favourable mix. In an optimization like this, the costs of maintenance and reduced durability are normally neglected. In this deliverable, a model is presented for taken these costs into account.

The environmental impact will be reduced, when the outcome will be more durable energy systems and more renewable energy will be used. It is anticipated that the heat network will be operated differently. The new strategy of operating the heat network can lead to higher temperature peaks, more temperature cycles, and higher average temperature.
A cost function, given from the model, for operating a district heating network at increased temperature volatility and at increased average temperature has been developed. The operating temperature peaks must be limited to certain given design values or to levels already in use for the system since several years.

The cost function considers damages of service pipes caused of increase fatigue due to increased operating temperature volatility and degradation of polyurethane foam due to increased average operating temperatures.