5th generation district heating and cooling systems as a solution for renewable urban thermal energy supply

Abstract. In order to reduce greenhouse gas emissions and decrease dependency on depleting fossil fuel resources the shift to a renewable energy system is necessary. District heating and cooling systems are a viable solution to provide heat and cold in urban environments. Renewable heat and cold sources that may get incorporated in future urban energy systems will not provide the same high temperature output as current fossil fuel fired systems. Fifth generation district heating and cooling (5GDHC) systems are decentralized, bi-directional, close to ground temperature networks that use direct exchange of warm and cold return flows and thermal storage to balance thermal demand as much as possible. 5GDHC offers a way to incorporate low temperature renewable heat sources including shallow geothermal energy, as well as reduce total demand by recuperating generated heat from cooling and generated cold from heating. The large scale of 5GDHC allows for optimal design of technical parts like heat pumps and thermal storage vessels, while increasing overall system efficiency by incorporating a large variety of supply and demand profiles. We provide a definition for 5GDHC and show how this concept differs from conventional district heating systems. The Mijnwater system in Heerlen, the Netherlands is showing what a city-level 5GDHC system can look like.

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Evaluating the Potential Contribution of District Heating to the Flexibility of the Future Italian Power System

Energies ◽

10.3390/en15020584 ◽

2022 ◽

Vol 15 (2) ◽

pp. 584

Author(s):

Chiara Magni ◽

Sylvain Quoilin ◽

Alessia Arteconi

Keyword(s):

Power Systems ◽

Power System ◽

Large Scale ◽

District Heating ◽

Energy System ◽

Heat Pumps ◽

Electricity Sector ◽

Potential Contribution ◽

The Future ◽

Promising Solution

Flexibility is crucial to enable the penetration of high shares of renewables in the power system while ensuring the security and affordability of the electricity dispatch. In this regard, heat–electricity sector coupling technologies are considered a promising solution for the integration of flexible devices such as thermal storage units and heat pumps. The deployment of these devices would also enable the decarbonization of the heating sector, responsible for around half of the energy consumption in the EU, of which 75% is currently supplied by fossil fuels. This paper investigates in which measure the diffusion of district heating (DH) coupled with thermal energy storage (TES) units can contribute to the overall system flexibility and to the provision of operating reserves for energy systems with high renewable penetration. The deployment of two different DH supply technologies, namely combined heat and power units (CHP) and large-scale heat pumps (P2HT), is modeled and compared in terms of performance. The case study analyzed is the future Italian energy system, which is simulated through the unit commitment and optimal dispatch model Dispa-SET. Results show that DH coupled with heat pumps and CHP units could enable both costs and emissions related to the heat–electricity sector to be reduced by up to 50%. DH systems also proved to be a promising solution to grant the flexibility and resilience of power systems with high shares of renewables by significantly reducing the curtailment of renewables and cost-optimally providing up to 15% of the total upward reserve requirements.

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Achieving a Flexible and Sustainable Energy System: The Case of Kosovo

Energies ◽

10.3390/en12244753 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4753 ◽

Cited By ~ 1

Author(s):

Njomza Ibrahimi ◽

Alemayehu Gebremedhin ◽

Alketa Sahiti

Keyword(s):

Carbon Capture ◽

Large Scale ◽

Sustainable Energy ◽

Supply And Demand ◽

Energy System ◽

Heat Pumps ◽

Operating Efficiency ◽

Baseline Scenario ◽

Renewable Sources ◽

Sustainable Energy System

In today’s energy system, the diffusion of renewable-based technologies is accelerating rapidly. Development of mechanisms that support the large-scale deployment of renewables towards global warming and climate change mitigation continues to remain an issue of utter importance. The most important challenges the energy system of Kosovo faces today is the difficulty to meet all the demand for electricity, low operating efficiency and high release of greenhouse gas emissions, but specifically a large source of carbon dioxide (CO2). Consequently, this influences not only the stability of the system but the society as a whole. This paper addresses several possibilities for designing an adaptable energy system in Kosovo with the ability to balance electricity supply and demand which will meet the requirements for a more efficient, reliable and secure system. A new way of energy generating through integration of new renewable and non-renewable technologies is developed using the EnergyPLAN model. The system is based on available technologies: existing hydro, wind, photovoltaic (PV), combined heat and power (CHP) and new solar thermal, heat pumps and biomass. The baseline scenario 2015 was expanded by four additional scenarios, two for the year 2030 and two for the year 2050. The contribution of renewable sources in the primary energy supply (PES) in the performed scenarios was 14.8%, 34.1%, 38.4%, 69.7% and 68.3% respectively. Further, a very important component of this paper is the investigation of integrating carbon capture and sequestration (CCS) technology in the coal-based power plant as part of the analysis in the second scenario for 2050. The shift to zero-carbon energy system in Kosovo requires additional research and assessment in order to identify the untapped potential of renewable sources. However, from the results obtained it can be concluded that the goal of a secure, competitive and sustainable energy system in Kosovo state which will meet its long-term energy needs can be certainly achieved.

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Flexibility from Electric Boiler and Thermal Storage for Multi Energy System Interaction

Energies ◽

10.3390/en13010098 ◽

2019 ◽

Vol 13 (1) ◽

pp. 98 ◽

Cited By ~ 3

Author(s):

Rakesh Sinha ◽

Birgitte Bak-Jensen ◽

Jayakrishnan Radhakrishna Pillai ◽

Hamidreza Zareipour

Keyword(s):

Curve Fitting ◽

Estimation Error ◽

District Heating ◽

Thermal Storage ◽

Energy System ◽

Heat Pumps ◽

Residential Area ◽

Spot Price ◽

Neural Net ◽

Electric Boiler

Active use of heat accumulators in the thermal system has the potential for achieving flexibility in district heating with the power to heat (P2H) units, such as electric boilers (EB) and heat pumps. Thermal storage tanks can decouple demand and generation, enhancing accommodation of sustainable energy sources such as solar and wind. The overview of flexibility, using EB and storage, supported by investigating the nature of thermal demand in a Danish residential area, is presented in this paper. Based on the analysis, curve-fitting tools, such as neural net and similar day method, are trained to estimate the residential thermal demand. Utilizing the estimated demand and hourly market spot price of electricity, the operation of the EB is scheduled for storing and fulfilling demand and minimizing energy cost simultaneously. This demonstrates flexibility and controlling the EB integrated into a multi-energy system framework. Results show that the curve fitting tool is effectively suitable to acknowledge thermal demands of residential area based on the environmental factor as well as user behaviour. The thermal storage has the capability of operating as a flexible load to support P2H system as well as minimize the effect of estimation error in fulfilling actual thermal demand simultaneously.

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

Applied Sciences ◽

10.3390/app9153194 ◽

2019 ◽

Vol 9 (15) ◽

pp. 3194 ◽

Cited By ~ 2

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.

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Techno-Economic Analysis of Power-to-Heat Systems

E3S Web of Conferences ◽

10.1051/e3sconf/202123803003 ◽

2021 ◽

Vol 238 ◽

pp. 03003

Author(s):

Alberto Vannoni ◽

Alessandro Sorce ◽

Alberto Traverso ◽

Aristide Fausto Massardo

Keyword(s):

Large Scale ◽

Renewable Energy Sources ◽

Large Fraction ◽

District Heating ◽

Electrical Energy ◽

Energy System ◽

Heat Pumps ◽

Point Of View ◽

Thermal Source ◽

Economic Point

The heating and cooling sector, responsible for a large fraction of greenhouse emissions, may have a large scale impact on the energy system evolution contributing to smart industrial and domestic electrification; at the same time the recent increase of renewable energy sources installation, posing a threat in terms of grid stability, makes available a considerable amount of clean and cheap electrical energy during peak hours production. Power to heat technologies constitute a promising solution to face both these issues reducing the electric demand variability and decarbonizing the heat production. Large vapor compression heat pumps are a reliable technology able to compete, under the economic point of view, with the heat-only-boilers in order to serve district heating networks. Performance and economic profitability of a compression cycle is strongly dependent on available thermal source and the temperature of water delivered to the network. The present work explores and compares performance and economic indicators under different installation conditions, considering compression heat pumps employing four different fluids: a traditional HCF (R134a) and three natural fluids, ammonia (R717), butane (R600), and propane (R290), often preferred nowadays to HCFs due to the lower global warming potential.

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

Environmental and Climate Technologies ◽

10.2478/rtuect-2020-0117 ◽

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.

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