Modelling the effect of the transmitted information quality on the management of 4th Generation district heating
Résumé
The association of Information and Communication Technologies with energy systems has demonstrated its benefits in the case of electrical smart grids whereas it is still in progress for district heating. Some similarities exists between electricity and heat energy (diversity and number of systems connected to the networks, intermittence of some energy sources, consumers becoming prosumers, coupling with other form of energy grids, storage opportunity …). However some specificities in the case of heat energy and the associated technologies must be taken into account (time characteristics and inertia, thermal losses, infrastructures costs and constraints…) for a transformation towards 4 th DH. Moreover the transformation must not be imagined only for future networks but also for existing ones. In particular, communication solutions from and towards substations, energy sources and central communication point, must be robust, easy to implement and at the lowest cost. Such communication solutions (Wi-Fi, LoRa®, SIGFOX, QOWISIO…) already used for many applications related to Internet of Things (IoT) require in-depth study for compatibility of their constraints with required quality of information transmitted in the case of district heating. The modelling work presented in this paper focuses on impact of quality of information on the management of the different energy systems connected to the network. Hourly heat demand profiles (similar to those which could be monitored at the substations of a given district heating) are studied via time and frequency analysis to identify the lowest level of information necessary for decision making regarding management of energy systems. These signals are degraded in a way that corresponds to limitations of communication technologies (loss of information, transmission capacity, noisy signal…). These demand profiles are used as input of the modelling tool HeatGrid. HeatGrid is a pseudo-dynamic model that simulates hourly optimal use of multi-sources district heating of any size, at each substation. It is based on oriented graph formalism and linear programming. The tool optimizes heat production mix at each time step by minimizing exploitation costs. Simulations enable to test the potential of communication technologies for the optimal management of heat sources. They also permit to assess the impact of transmission characteristics on the optimal strategies generated by HeatGrid. Results show that the amount of information, the signal sample frequency as well as information losses are not so restrictive for smart heat grids management than for electrical grids. Low cost communication solutions promising for shifting existing network to 4 th generation DH can be considered (LoRa®, SigFox…)