Equivalent models of District Heating (DH) systems for on-line minimization of operational costs of the complete DH system
The purpose of this research project has been to develope and test equivalent models of district heating (DH) systems with regard to on-line optimization of the operational costs of the complete system. The mathematical and physical background for simulations of flow and transient temperatures in DH networks is outlined, and the models have been verified by data from the Roskilde branch of the VEKS transmission system.
The goal is to develop and test equivalent models of District Heating (DH) systems. Various degrees of aggregation will be tested and compared with a full description of the DH system. The equivalent models will be tested with regard to: - Flow distributions and time delays in the DH network. - Return temperatures from the house stations. - The heat loss from the DH network and the energy consumption of the pumps, parameters which influence the operational costs. Systematic collection of operational data has previously been carried out from the DH systems Ishoej and VEKS, but if necessary other DH systems will be incorporated as well. The project will separate the DH systems into two groups: In the first group heat demands and temperatures in the buildings will be known from the installed heat meters. In the second group this information is not available on-line, but only form readings of the heat meters for billing purposes. In both cases the equivalent models will be compared with a full description of the DH system
A method for aggregation of DH networks (without loops) has been developed with regard to simulation of transient temperatures and a subsequent calculation of the operational costs. It has been demonstrated in a number of cases that equivalent DH networks have properties close to the original DH network, for instance with respect to the return temperature of the DH plant. This holds true even if the assumptions for generating the equivalent network are not exactly fulfilled. When the equivalent DH network is constructed, the complexity of the network is reduced until a line network remains. This line network can be further reduced by collating nearby nodes of the line network. The difference between a line network with ten pipes, and the original DH network, is small with regard to the retun temperature at the DH plant
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Participants
| Partner | Subsidy | Auto financing |
|---|---|---|
| Danmarks Tekniske Universitet (DTU) |
Contact
Bygning 402
DK-2800 Lyngby, Denmark
Bøhm, Benny (professor), 45932711, bbohm@nwserv.vk.dtu.dk
Øvr. Partnere: Forskningscenter Risø. Afd. for Systemanalyse