District heat network as a short-term energy storage

In this article, we show how a revised district heat network control strategy can be employed to utilize the storage capabilities of the network. An optimization problem is formulated, with minimum operating costs as the objective. Allowing the district heat supply temperature to vary freely within given boundaries results in approximately 2% reduction in annual heat provision costs, in comparison to a reference control scheme in a case study. The benefits of added heat storage functionality in the network are greatest when there is a large difference between district heat generation costs from the available heat sources. In general, supply temperature optimization results in increased operational hours of those plants, whose variable costs are the lowest. (C) 2019 Elsevier Ltd. All rights reserved.