Supra-Regional District Heating Networks: A Missing Infrastructure for a Sustainable Energy System

In analogy to electricity transmission networks, this paper analyzes the concept of supra-regional district heating networks (SR-DHN), connecting a large number of actors. Using a back-casting approach, a SR-DHN is assumed to exist and thus, implementation challenges, such as economic feasibility and energy losses, are circumvented in the first step (but are analyzed in the discourse). The paper then analyzes, in an interdisciplinary qualitative manner and supported by a case study, what technical, operational, economic and legal issues must have been resolved. Results show that the heat transmission network, being the backbone of the SR-DHN, is an expensive infrastructure, but is likely to become economic in a non-fossil energy system. By decreasing the reliance on single waste heat sources, SR-DHN allows longer payback periods and can thus be an enabler for using industrial waste heat. However, involving many actors requires comprehensive contractual foundations. The derived hypothesis is that SR-DHN, which is predominantly fed by waste heat, shall be operated with lower temperatures in winter (feeding the return while minimizing expensive winter losses) and high temperatures in summer (enabling alternative usages while accepting high but inexpensive summer losses).

Download Full-text

Integration of Renewables in DHC for Sustainable Living Workshop

Proceedings ◽

10.3390/proceedings2020065030 ◽

2021 ◽

Vol 65 (1) ◽

pp. 30

Author(s):

María Victoria Cambronero Vázquez ◽

Jack Corscadden ◽

Antonio Garrido Marijuan ◽

Giulia Barbagelata ◽

Georg Hamann ◽

...

Keyword(s):

Renewable Energy ◽

Fossil Fuels ◽

Waste Heat ◽

District Heating ◽

Energy System ◽

Heat Sources ◽

Sustainable Living ◽

New Ideas ◽

Integration Of Renewables ◽

Sustainable Energy System

There is a large potential to integrate substantial shares of renewable energy and waste heat sources in district heating and/or cooling networks (DHC), reducing dependency of DHC on fossil fuels and ultimately leading to a more efficient and sustainable energy system. Several EU funded projects are currently working on this topic. The objective of the workshop aimed to share the WEDISTRICT project concept with other sister projects and interested stakeholders in order to exchange new ideas, lessons learnt from implementation and proposals about the successful integration of renewable technologies in DHC and urban regeneration.

Download Full-text

Investigation on Relative Heat Losses and Gains of Heating and Cooling Networks

Environmental and Climate Technologies ◽

10.2478/rtuect-2021-0035 ◽

2021 ◽

Vol 25 (1) ◽

pp. 479-490

Author(s):

Violeta Madan ◽

Ingo Weidlich

Keyword(s):

District Heating ◽

Energy System ◽

Heat Losses ◽

Heat Sources ◽

Temperature Level ◽

Near Surface ◽

Heating And Cooling ◽

Surface Soil Temperature ◽

Steady State Heat ◽

Sustainable Energy System

Abstract The integration of district heating (DH) and cooling (DC) in the sustainable energy system of the future requires a significant reduction in operating temperatures. Supply temperatures below 70 °C are required for new 4th Generation DH. Main benefits are the use of low exergy heat sources and the reduction of heat losses. The reduction of heat losses is achieved by reducing the driving temperature difference between the medium pipe and the ground. The decrease of the return temperature level is limited by the consumer behaviour and the ground temperature level. As a consequence, the reduction of the supply temperature is accompanied by a reduction of the maximum transmittable heat flow. For energy efficiency and economic reasons, the relative heat losses are therefore an important design value for DH networks. The study proposes an approach to estimate the relative heat losses by using steady-state heat loss models and analyses the values for different DH generations. In particular, due to the rising of the near-surface soil temperature, the relative cold losses are also studied.

Download Full-text

Unconventional Excess Heat Sources for District Heating in a National Energy System Context

Energies ◽

10.3390/en13195068 ◽

2020 ◽

Vol 13 (19) ◽

pp. 5068 ◽

Cited By ~ 2

Author(s):

Steffen Nielsen ◽

Kenneth Hansen ◽

Rasmus Lund ◽

Diana Moreno

Keyword(s):

System Analysis ◽

Renewable Energy Sources ◽

District Heating ◽

Energy System ◽

Economic Feasibility ◽

Electricity Production ◽

Heat Sources ◽

Excess Heat ◽

Smart Energy Systems ◽

System Context

District heating (DH) is an important technology in future smart energy systems as it allows for an efficient implementation of various renewable energy sources. As DH develops towards lower temperatures and renewable electricity production increases, new types of heat sources become relevant. Thus, the aim of this article is to assess the potential for utilizing four unconventional excess heat (UEH) sources in DH systems, namely: Data centers, wastewater treatment, metros and service sector buildings. The main method used to assess the UEH potentials is an energy system analysis focusing on the availability and economic feasibility of utilizing the UEH sources in national contexts. The analysis consists of 2015 and 2050 scenarios for Germany, Spain and France. The results show a potential for utilizing the UEH potentials in all three countries, both in 2015 and 2050 systems. The potentials are highest in the 2050 scenarios, primarily due to larger DH shares. Furthermore, the potentials are limited by competition with other heat supply sources, conjunction with heat demands and feasible heat pump operation. In conclusion, the four UEH sources could impact the local DH systems, but in a national energy system context they are expected to play a minor role.

Download Full-text

RELaTED Project: New Developments on Ultra-Low Temperature District Heating Networks

Proceedings ◽

10.3390/proceedings2020065008 ◽

2020 ◽

Vol 65 (1) ◽

pp. 25

Author(s):

Antonio Garrido Marijuan ◽

Roberto Garay ◽

Mikel Lumbreras ◽

Víctor Sánchez ◽

Olga Macias ◽

...

Keyword(s):

Low Temperature ◽

High Performance ◽

Waste Heat ◽

District Heating ◽

Hot Water ◽

Thermal Systems ◽

Heating Source ◽

Wide Range ◽

Thermal Sources ◽

Heating Networks

District heating networks deliver around 13% of the heating energy in the EU, being considered as a key element of the progressive decarbonization of Europe. The H2020 REnewable Low TEmperature District project (RELaTED) seeks to contribute to the energy decarbonization of these infrastructures through the development and demonstration of the following concepts: reduction in network temperature down to 50 °C, integration of renewable energies and waste heat sources with a novel substation concept, and improvement on building-integrated solar thermal systems. The coupling of renewable thermal sources with ultra-low temperature district heating (DH) allows for a bidirectional energy flow, using the DH as both thermal storage in periods of production surplus and a back-up heating source during consumption peaks. The ultra-low temperature enables the integration of a wide range of energy sources such as waste heat from industry. Furthermore, RELaTED also develops concepts concerning district heating-connected reversible heat pump systems that allow to reach adequate thermal levels for domestic hot water as well as the use of the network for district cooling with high performance. These developments will be demonstrated in four locations: Estonia, Serbia, Denmark, and Spain.

Download Full-text

State estimation models of district heating networks for integrated energy system considering incomplete measurements

Applied Energy ◽

10.1016/j.apenergy.2020.116105 ◽

2021 ◽

Vol 282 ◽

pp. 116105

Author(s):

Suhan Zhang ◽

Wei Gu ◽

Haifeng Qiu ◽

Shuai Yao ◽

Guangsheng Pan ◽

...

Keyword(s):

State Estimation ◽

District Heating ◽

Energy System ◽

Integrated Energy System ◽

Heating Networks ◽

Estimation Models

Download Full-text

Method for Redesign of District Heating Networks within Transition from the 2nd to the 3rd Generation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.657.689 ◽

2014 ◽

Vol 657 ◽

pp. 689-693

Author(s):

Răzvan Corneliu Lefter ◽

Daniela Popescu ◽

Alexandrina Untăroiu

Keyword(s):

District Heating ◽

Design Stage ◽

Heating Systems ◽

Load Duration ◽

Load Duration Curve ◽

District Heating Systems ◽

Consumption Rates ◽

Heat Loads ◽

Heating Networks

Important investmentsare made lately in the area of district heating, as a technology capable ofhelping countries to reach sustainability goals. In Romania, European fundswere spent for transition from the 2nd to the 3rdgeneration of district heating systems. The lack of appropriate monitoringsystems in old district heating systems makes optimisation nowadays very difficult,especially because nominal values used in the first design stage areoverestimated. Realistic nominal heat loads are necessary to make goodestimations of hydraulic parameters to be used for redesign. This studyproposes a method that uses the heat load duration curve theory to identify theappropriate nominal heat loads to be used for redesign. Comparison betweenresults obtained by applying the nominal heat loads of each consumer, as theywere established in the first design stage, and the ones identified by theproposed method are analyzed in a case study. The results show that errors arein the +/- 3% band, between the metered heat consumption rates and the proposedrates. The new method can be used for the sizing of pumps and district heatingnetworks after retrofit, in order to get better adjustments of the circulationpumps and increase of the energy efficiency.

Download Full-text