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

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.

Download Full-text

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

Advances in Geosciences ◽

10.5194/adgeo-49-129-2019 ◽

2019 ◽

Vol 49 ◽

pp. 129-136 ◽

Cited By ~ 8

Author(s):

Stef Boesten ◽

Wilfried Ivens ◽

Stefan C. Dekker ◽

Herman Eijdems

Keyword(s):

Large Scale ◽

Fossil Fuel ◽

Supply And Demand ◽

District Heating ◽

Thermal Storage ◽

Energy System ◽

Heat Pumps ◽

Urban Environments ◽

Cooling Systems ◽

Heating And Cooling

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.

Download Full-text

A Method for Optimizing and Spatially Distributing Heating Systems by Coupling an Urban Energy Simulation Platform and an Energy System Model

Resources ◽

10.3390/resources10050052 ◽

2021 ◽

Vol 10 (5) ◽

pp. 52

Author(s):

Annette Steingrube ◽

Keyu Bao ◽

Stefan Wieland ◽

Andrés Lalama ◽

Pithon M. Kabiro ◽

...

Keyword(s):

District Heating ◽

Energy Systems ◽

Energy System ◽

Heat Pumps ◽

Energy Simulation ◽

Heating Systems ◽

Optimal Amount ◽

Urban City ◽

Urban Energy ◽

Building Level

District heating is seen as an important concept to decarbonize heating systems and meet climate mitigation goals. However, the decision related to where central heating is most viable is dependent on many different aspects, like heating densities or current heating structures. An urban energy simulation platform based on 3D building objects can improve the accuracy of energy demand calculation on building level, but lacks a system perspective. Energy system models help to find economically optimal solutions for entire energy systems, including the optimal amount of centrally supplied heat, but do not usually provide information on building level. Coupling both methods through a novel heating grid disaggregation algorithm, we propose a framework that does three things simultaneously: optimize energy systems that can comprise all demand sectors as well as sector coupling, assess the role of centralized heating in such optimized energy systems, and determine the layouts of supplying district heating grids with a spatial resolution on the street level. The algorithm is tested on two case studies; one, an urban city quarter, and the other, a rural town. In the urban city quarter, district heating is economically feasible in all scenarios. Using heat pumps in addition to CHPs increases the optimal amount of centrally supplied heat. In the rural quarter, central heat pumps guarantee the feasibility of district heating, while standalone CHPs are more expensive than decentral heating technologies.

Download Full-text

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.

Download Full-text

A methodology for designing decentralised energy systems with predictive control for heat pumps and thermal storage

E3S Web of Conferences ◽

10.1051/e3sconf/201911106014 ◽

2019 ◽

Vol 111 ◽

pp. 06014

Author(s):

Andrew Lyden ◽

Paul Tuohy

Keyword(s):

Predictive Control ◽

Thermal Characteristic ◽

Thermal Characteristics ◽

Energy Systems ◽

Thermal Storage ◽

Energy System ◽

Heat Pumps ◽

Hot Water ◽

Water Tank ◽

Electricity Cost

Decentralised energy systems provide the potential for adding energy system flexibility by separating demand/supply dynamics with demand side management and storage technologies. They also offer an opportunity for implementing technologies which enable sector coupling benefits, for example, heat pumps with controls set to use excess wind power generation. Gaps in this field relating to planning-level modelling tools have previously been identified: thermal characteristic modelling for thermal storage and advanced options for control. This paper sets out a methodology for modelling decentralised energy systems including heat pumps and thermal storage with the aim of assisting planning-level design. The methodology steps consist of: 1) thermal and electrical demand and local resource assessment methods, 2) energy production models for wind turbines, PV panels, fuel generators, heat pumps, and fuel boilers, 3) bi-directional energy flow models for simple electrical storage, hot water tank thermal storage with thermal characteristics, and a grid-connection, 4) predictive control strategy minimising electricity cost using a 24-hour lookahead, and 5) modelling outputs. Contributions to the identified gaps are examined by analysing the sensible thermal storage model with thermal characteristics and the use of the predictive control. Future extensions and applications of the methodology are discussed.

Download Full-text

Synthesis and Optimal Operation of Smart Microgrids Serving a Cluster of Buildings on a Campus with Centralized and Distributed Hybrid Renewable Energy Units

Energies ◽

10.3390/en12040745 ◽

2019 ◽

Vol 12 (4) ◽

pp. 745 ◽

Cited By ~ 7

Author(s):

Daniele Testi ◽

Paolo Conti ◽

Eva Schito ◽

Luca Urbanucci ◽

Francesco D’Ettorre

Keyword(s):

Renewable Energy ◽

Combustion Engine ◽

District Heating ◽

Energy System ◽

Primary Energy ◽

Heat Pumps ◽

Optimal Operation ◽

Optimal Control Strategy ◽

Renewable Energy Technologies ◽

Energy Technologies

Micro-district heating networks based on cogeneration plants and renewable energy technologies are considered efficient, viable and environmentally-friendly solutions to realizing smart multi-energy microgrids. Nonetheless, the energy production from renewable sources is intermittent and stochastic, and cogeneration units are characterized by fixed power-to-heat ratios, which are incompatible with fluctuating thermal and electric demands. These drawbacks can be partially overcome by smart operational controls that are capable of maximizing the energy system performance. Moreover, electrically driven heat pumps may add flexibility to the system, by shifting thermal loads into electric loads. In this paper, a novel configuration for smart multi-energy microgrids, which combines centralized and distributed energy units is proposed. A centralized cogeneration system, consisting of an internal combustion engine is connected to a micro-district heating network. Distributed electric heat pumps assist the thermal production at the building level, giving operational flexibility to the system and supporting the integration of renewable energy technologies, i.e., wind turbines, photovoltaic panels, and solar thermal collectors. The proposed configuration was tested in a hypothetical case study, namely, a University Campus located in Trieste, Italy. The system operation is based on a cost-optimal control strategy and the effect of the size of the cogeneration unit and heat pumps was investigated. A comparison with a conventional configuration, without distributed heat pumps, was also performed. The results show that the proposed configuration outperformed the conventional one, leading to a total-cost saving of around 8%, a carbon emission reduction of 11%, and a primary energy saving of 8%.

Download Full-text

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.

Download Full-text

Planning for a Low Carbon Future? Comparing Heat Pumps and Cogeneration as the Energy System Options for a New Residential Area

Energies ◽

10.3390/en8099137 ◽

2015 ◽

Vol 8 (9) ◽

pp. 9137-9154 ◽

Cited By ~ 8

Author(s):

Jukka Heinonen ◽

Jani Laine ◽

Karoliina Pluuman ◽

Eeva-Sofia Säynäjoki ◽

Risto Soukka ◽

...

Keyword(s):

Energy System ◽

Heat Pumps ◽

Residential Area ◽

Low Carbon

Download Full-text

Meeting UK heat demands in zero emission renewable energy systems using storage and interconnectors

10.21203/rs.3.rs-629226/v1 ◽

2021 ◽

Author(s):

Tiziano Gallo Cassarino ◽

Mark Barrett

Keyword(s):

Heat Supply ◽

District Heating ◽

Energy System ◽

Heat Pumps ◽

System Modelling ◽

Reference Scenario ◽

System Architectures ◽

Trade Offs ◽

Electrolytic Hydrogen ◽

Zero Emission

Abstract With over a third of the United Kingdom's greenhouse gas emissions, decarbonising heat is key to achieving the Government's net-zero target by 2050. Here, we simulate high renewable zero-emission energy system architectures with heat supply based on the major options of district heating, heat pumps, and electrolytic hydrogen boilers. We adopt a novel whole system modelling approach that combines meteorology-driven hourly simulations of demand and supply with storage, flexible technologies, and interconnections on the European scale. Our results show that systems with heat supply based on consumer or district heat pumps require about four times less electricity per unit of heat, with a heat cost about half of that from electrolytic hydrogen boilers. Furthermore, we compare trade-offs between investment in different infrastructure components. For example, we find that, compared to the reference scenario, increasing renewable capacity by 33%, or interconnections by 200%, can lower system storage capacity by up to 50%.

Download Full-text

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.

Download Full-text

Enabling Technologies for Sector Coupling: A Review on the Role of Heat Pumps and Thermal Energy Storage

Energies ◽

10.3390/en14248195 ◽

2021 ◽

Vol 14 (24) ◽

pp. 8195

Author(s):

Omais Abdur Rehman ◽

Valeria Palomba ◽

Andrea Frazzica ◽

Luisa F. Cabeza

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Renewable Energy Sources ◽

District Heating ◽

Energy Systems ◽

Energy System ◽

Heat Pumps ◽

Enabling Technologies

In order to reduce greenhouse gas emissions, current and future energy systems need to be made more efficient and sustainable. This change can be accomplished by increasing the penetration of renewable energy sources and using efficient technologies in energy generation systems. One way to improve the operation of the whole energy system is through the generation and end-use sector coupling. Power-to-heat energy conversion and storage technologies, in this view, are enabling technologies that can help in balancing and improving the efficiency of both thermal and electric grids. In the present paper, a comprehensive analysis of the role of heat pumps and thermal energy storage for sector coupling is presented. The main features of the analyzed technologies are presented in the context of smart electric grid, district heating and cooling and multi-carrier energy systems, and recent findings and developments are highlighted. Finally, the technical, social, and economic challenges in the adoption of investigated technologies are discussed.

Download Full-text