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

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.

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

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3380
Author(s):  
Simon Moser ◽  
Stefan Puschnigg
Keyword(s):  
Waste Heat ◽  
District Heating ◽  
Energy System ◽  
Economic Feasibility ◽  
Heat Sources ◽  
Transmission Networks ◽  
Implementation Challenges ◽  
Sustainable Energy System ◽  
Heating Networks

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).

scholarly journals Integration of Renewables in DHC for Sustainable Living Workshop

Proceedings ◽  
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.

scholarly journals Integration of Reversible Heat Pumps in Trigeneration Systems for Low-Temperature Renewable District Heating and Cooling Microgrids

2019 ◽  
Vol 9 (15) ◽  
pp. 3194 ◽  
Author(s):  
Urbanucci ◽  
Testi ◽  
Bruno
Keyword(s):  
Low Temperature ◽  
Carbon Dioxide Emissions ◽  
Energy Demand ◽  
Water Distribution ◽  
District Heating ◽  
Energy System ◽  
Heat Pumps ◽  
Energy Technologies ◽  
Heating And Cooling ◽  
Viable Solution

District heating and cooling networks based on trigeneration systems and renewable energy technologies are widely acknowledged as an energy efficient and environmentally benign solution. These energy systems generally include back-up units, namely fossil-fuel boilers and electric chillers, to enhance system flexibility and cover peak energy demand. On the other hand, 4th generation district heating networks are characterized by low-temperature water distribution to improve energy and exergy efficiencies. Moreover, reversible heat pumps are a versatile technology, capable of providing both heating and cooling, alternately. In this paper, the integration of reversible heat pumps as single back-up units in hybrid renewable trigeneration systems serving low-energy micro-district heating and cooling networks is investigated. A detailed modeling of the system is provided, considering part-load and ambient condition effects on the performance of the units. Size and annual operation of the proposed system are optimized in a case study, namely a large office building located in Pisa (Italy), by means of a genetic algorithm-based procedure. A comparison with the conventional trigeneration system is performed in terms of economic and environmental perspectives. Results show that the integration of reversible heat pumps is an economically viable solution capable of reducing by 7% the equivalent annual cost, increasing the installed power of renewables up to 23%, and lowering by 11% carbon dioxide emissions, compared to the energy system with conventional back-up units.

scholarly journals District Heating and Cooling Systems

2021 ◽  
Author(s):  
Iván De la Cruz ◽  
Carlos E. Ugalde-Loo
Keyword(s):  
Renewable Energy Sources ◽  
District Heating ◽  
Energy System ◽  
Optimal Operation ◽  
Low Carbon ◽  
Automatic Control Systems ◽  
Heating And Cooling ◽  
Net Zero ◽  
Cold Store ◽  
Low Carbon Technologies

Decarbonisation of the energy sector is a crucial ambition towards meeting net-zero targets and achieving climate change mitigation. Heating and cooling accounts for over a third of UK greenhouse emissions and, thus, decarbonisation of this sector has attracted significant attention from a range of stakeholders, including energy system operators, manufacturers, research institutions and policy makers. Particularly, the role of district heating and cooling (DHC) systems will be critical, as these two energy vectors are central to our lives not only for comfort and daily activities, but also to facilitate productive workplaces and to run a variety of industrial processes. The optimal operation of DHC systems and the design of efficient strategies to produce heat and cold, store thermal energy, and meet heating and cooling demands, together with an increased integration of low carbon technologies and local renewable energy sources, are vital to reduce energy consumption and carbon emissions alike. This chapter reviews relevant aspects of DHC systems, their main elements, automatic control systems and optimal management.

scholarly journals SWOT analysis of ST integration in DHC systems

2020 ◽  
Author(s):  
Paolo Leoni ◽  
Ralf-Roman Schmidt ◽  
Roman Geyer ◽  
Patrick Reiter
Keyword(s):  
Swot Analysis ◽  
District Heating ◽  
Global Scale ◽  
Solar Thermal ◽  
Heat Sources ◽  
Heating And Cooling ◽  
Operation Costs ◽  
Almost Everywhere ◽  
Systemic Level

Solar thermal (ST) energy is one of the few renewable heat sources that is available almost everywhere and can bring multiple benefits to district heating and cooling (DHC) networks (on an environmental and systemic level) with very low operation costs and risks. However, the current share of ST in DHC networks is almost zero on a global scale.

Heat Pump Energy System for District Heating and Cooling in the Tokyo Area

Heat Pumps ◽  
1990 ◽  
pp. 681-689
Author(s):  
H. YOSHIDA ◽  
T. NIHEI ◽  
S. IGARASHI
Keyword(s):  
Heat Pump ◽  
Pump Energy ◽  
District Heating ◽  
Energy System ◽  
Heating And Cooling

scholarly journals Large-Scale Geothermal Collector Systems for 5th Generation District Heating and Cooling Networks

2021 ◽  
Vol 13 (11) ◽  
pp. 6035
Author(s):  
Robin Zeh ◽  
Björn Ohlsen ◽  
David Philipp ◽  
David Bertermann ◽  
Tim Kotz ◽  
...  
Keyword(s):  
Low Temperature ◽  
Heat Exchangers ◽  
Large Scale ◽  
Waste Heat ◽  
Freezing Point ◽  
Residential Buildings ◽  
District Heating ◽  
Solar Irradiation ◽  
Heat Sources ◽  
Heating And Cooling

Low temperature district heating and cooling networks (5GDHC) in combination with very shallow geothermal energy potentials enable the complete renewable heating and cooling supply of settlements up to entire city districts. With the help of 5GDHC, heating and cooling can be distributed at a low temperature level with almost no distribution losses and made useable to consumers via decentralized heat pumps (HP). Numerous renewable heat sources, from wastewater heat exchangers and low-temperature industrial waste heat to borehole heat exchangers and large-scale geothermal collector systems (LSC), can be used for these networks. The use of large-scale geothermal collector systems also offers the opportunity to shift heating and cooling loads seasonally, contributing to flexibility in the heating network. In addition, the soil can be cooled below freezing point due to the strong regeneration caused by the solar irradiation. Multilayer geothermal collector systems can be used to deliberately generate excessive cooling of individual areas in order to provide cooling energy for residential buildings, office complexes or industrial applications. Planning these systems requires expertise and understanding regarding the interaction of these technologies in the overall system. This paper provides a summary of experience in planning 5GDHC with large-scale geothermal collector systems as well as other renewable heat sources.

scholarly journals Optimal Design and Dispatch of Electrically Driven Heat Pumps and Chillers for a New Development Area

2020 ◽  
Vol 24 (3) ◽  
pp. 470-482
Author(s):  
Henrik Pieper ◽  
Torben Ommen ◽  
Brian Elmegaard ◽  
Anna Volkova ◽  
Wiebke Brix Markussen
Keyword(s):  
Heat Source ◽  
Optimization Model ◽  
Large Scale ◽  
District Heating ◽  
Heat Pumps ◽  
Mixed Integer ◽  
Heat Sources ◽  
Sources And Sinks ◽  
Heating And Cooling ◽  
New Development

AbstractLarge-scale heat pumps (HPs) and refrigeration plants are essential technologies to decarbonise the heating and cooling sector. District heating and cooling (DHC) can be supplied with low carbon footprint, if power generated from renewable energy sources is used. The simultaneous supply of DHC is often not considered in energy planning, nor the characteristics of the heat source and sink. Simplified approaches may not reveal the true potential of HPs and chillers. In this paper, different heat sources and sinks and their characteristics were considered for the simultaneous supply of DHC based on large-scale HPs and refrigeration plants. An optimization model was developed based on mixed-integer linear programming. The model is able to identify ideal production and storage capacities, heat sources and sinks based on realistic hourly operation profiles. By doing so, it is possible to identify the most economical or sustainable supply of DHC using electricity. The optimization model was applied to the Nordhavn area, a new development district of Copenhagen, Denmark. The results show that a combination of different heat sources and sinks is ideal for the case study. A HP that uses the district cooling network as a heat source to supply DHC was shown to be very efficient and economical. Groundwater and sewage water HPs were proposed for an economical supply of district heating. The Pareto frontier showed that a large reduction in annual CO2 emissions is possible for a relatively small increase in investments.

scholarly journals The future of DH and the role of solar thermal energy

2020 ◽  
Author(s):  
Ralf-Roman Schmidt ◽  
Paolo Leoni ◽  
Hamid Aghaie
Keyword(s):  
District Heating ◽  
Global Scale ◽  
Solar Thermal ◽  
Heat Sources ◽  
Solar Thermal Energy ◽  
Heating And Cooling ◽  
Operation Costs ◽  
Almost Everywhere ◽  
Systemic Level

Solar thermal (ST) energy is one of the few renewable heat sources that is available almost everywhere and can bring multiple benefits to district heating and cooling (DHC) networks (on an environmental and systemic level) with very low operation costs and risks. However, the current share of ST in DHC networks is almost zero on a global scale.

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