The measurement of physical parameters conducted on a central heat distribution network was used to determine heat loss using pipe dimensional analysis.
Combining the heat distribution network retrofit with savings energy interventions on buildings' facades, three different scenarios with different feasibility indexes have been analysed: Baseline (DH refurbishment), Medium (DH refurbishment plus windows retrofit) and Advanced (DH refurbishment and a complete retrofit).
District heat for the building stock within the 440 km heat distribution network is supplied from the Haapaniemi 2 and 3 cogenerating stations with respective capacities of 120 MW heat and 60 MW power, and 80 MW heat and 49 MW power.
Research activity has been focused on the development and integration of a code for dynamic simulation of heat distribution networks with a code for thermo-economics optimization of CHP systems, increasing the possibility of optimizing the matching between CHP plant and thermal users, through the exploitation of thermal storage capacity of the networks.
"People are now starting to think about urban heat distribution networks everywhere," says Doug King, a consultant specialising in design innovation and sustainable development in construction.
At the present time conventional HVAC equipment is used for maintaining the heat-distribution-network: this arrangement, however, has resulted in great energy saving only for AHBs with accessible natural water bodies.
The thermodynamic theory, which enables mathematical description and minimization of flow in a system, has long been used to efficiently design heat exchangers, heating-distribution networks, and electronics-cooling systems.
The district heating system applications started with large-scale, city-based geothermal district heating systems in Turkey, whereas the geothermal district heating centre and distribution networks have been designed according to the geothermal district heating system (GDHS) parameters.
REA cooperatives used a 6900 volt distribution network, distributed over their own network of transmission and distribution lines.
Several projects in progress are described, namely the increase of gas-firing in existing boiler installations, investment projects referring to the installation of gas engines for cogeneration of heat and electricity, utilization of the distribution network for the maximum utilization of gas and the designs of power-generation systems (using methane) for air conditioning in the mines.
