In Italy, the expression “scoprire l’acqua calda,” if literally translated into English, stands for “discovering hot water.” It means that what you just discovered is nothing new; indeed, it is pretty obvious. District heating is nothing more than a network of pipes distributing hot water. So, I thought that “scoprire l’acqua calda” could be a funny expression to stress this article’s aim: to inspire you, dear readers, and make you aware of the benefits this technology can bring in a global context. A novel, replicable methodology for assessing district heating potential will be presented. DISCOVERING HOT WATER
By Giulia Spirito, PhD Student at the Energy Department of Politecnico di Milano, Italy
clusters of heat demand are generated. They identify areas where the heat demand is high and very dense and, thus, where DH is expected to be feasible. The distribution net- work’s length and topology are estimated in each cluster, so that heat losses and costs related to the heat distribution can be computed. In step 3, the available heat sources are identi- fied, and the amount of recoverable heat is estimated. At this point, the transmission network connecting sources and heat demand cluster can also be designed in step 4. In step 4a, a triangulation algorithm generates the energy graph in which all the previously identified heat demand and heat sources are connected. Step 4b uses a routing algorithm to turn the linear connection into paths along the streets. In this way, more re- alistic costs associated with the transmission network can be estimated and considered in the ultimate step, step 5. Here, an optimization algorithm is applied to identify, for each clus- ter, what is the most economically feasible heating technology among DH and the individual solutions. The strength of this method, and this algorithm, in particular, is the capability of considering the spatial distribution of the elements that make up the whole system, with the possibility to take into account all the associated aspects and costs related to their location and mutual position. For each demand cluster, the total cost associated with DH, thus the sum of heat generation, heat transportation, and dis- tribution, is compared to the cost that would be paid if the
District heating (DH) is a well-known technology, in a way in- vented by the ancient Romans thousands of years ago. How- ever, despite the energy, economic and social benefits it can bring, it still is a niche technology. In this sense, district heating should be “discovered”: anyone should become aware of its po- tential to promote its diffusion. The methodology I will present has been developed based on open-source data and software to make it replicable in other contexts and so that results can be available for everyone. In the following, the main steps of the method and then the results obtained by applying it in Italy will be illustrated. The focus was on district heating based on renewables and excess heat sources. The main novelty stands in the high spatial res- olution achieved, with which it was possible not to overlook local parameters. It is, in fact, essential, when planning a DH network, to properly consider its local nature. Methodology The novel methodology has been developed in a project fund- ed by AIRU, the Italian District Heating Association. It was con- ducted by the research group “ReLab” of Politecnico di Milano and by Politecnico di Torino. It consists of 5 main steps that are illustrated in Figure 1. Step 1 illustrates the quantification and the mapping of the heat demand, and step 2 its spatial aggregation. In this way,
Figure 1: Illustration of the five steps composing the methodology
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