Business models combining heat pumps and district heating in buildings generate cost and emission savings

District heating enables an economical use of energy sources that would otherwise be wasted to cover the heating demands of buildings in urban areas. For efficient utilization of local waste heat and renewable heat sources, low distribution temperatures are of crucial importance. This study evaluates a local heating network being planned for a new building area in Trondheim, Norway, with waste heat available from a nearby ice skating rink. Two alternative supply temperature levels have been evaluated with dynamic simulations: low temperature (40 °C), with direct utilization of waste heat and decentralized domestic hot water (DHW) production using heat pumps; and medium temperature (70 °C), applying a centralized heat pump to lift the temperature of the waste heat. The local network will be connected to the primary district heating network to cover the remaining heat demand. The simulation results show that with a medium temperature supply, the peak power demand is up to three times higher than with a low temperature supply. This results from the fact that the centralized heat pump lifts the temperature for the entire network, including space and DHW heating demands. With a low temperature supply, heat pumps are applied only for DHW production, which enables a low and even electricity demand. On the other hand, with a low temperature supply, the district heating demand is high in the wintertime, in particular if the waste heat temperature is low. The choice of a suitable supply temperature level for a local heating network is hence strongly dependent on the temperature of the available waste heat, but also on the costs and emissions related to the production of district heating and electricity in the different seasons.

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Upgrading a District Heating System by Means of the Integration of Modular Heat Pumps, Geothermal Waters, and PVs for Resilient and Sustainable Urban Energy

Energies ◽

10.3390/en14092347 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2347

Author(s):

Elżbieta Hałaj ◽

Jarosław Kotyza ◽

Marek Hajto ◽

Grzegorz Pełka ◽

Wojciech Luboń ◽

...

Keyword(s):

District Heating ◽

Heating System ◽

Upper Jurassic ◽

Heat Pumps ◽

Water Levels ◽

Energy Potential ◽

Geothermal Waters ◽

District Heating System ◽

Heating And Cooling ◽

The City

Krakow has an extensive district heating network, which is approximately 900 km long. It is the second largest city in terms of the number of inhabitants in Poland, resulting in a high demand for energy—for both heating and cooling. The district heating of the city is based on coal. The paper presents the conception of using the available renewable sources to integrate them into the city’s heating system, increasing the flexibility of the system and its decentralization. An innovative solution of the use of hybrid, modular heat pumps with power dependent on the needs of customers in a given location and combining them with geothermal waters and photovoltaics is presented. The potential of deep geothermal waters is based on two reservoirs built of carbonate rocks, namely Devonian and Upper Jurassic, which mainly consist of dolomite and limestone. The theoretical potential of water intake equal to the nominal heating capacity of a geothermal installation is estimated at 3.3 and 2.0 MW, respectively. Shallow geothermal energy potential varies within the city, reflecting the complex geological structure of the city. Apart from typical borehole heat exchangers (BHEs), the shallower water levels may represent a significant potential source for both heating and cooling by means of water heat pumps. For the heating network, it has been proposed to use modular heat pumps with hybrid sources, which will allow for the flexible development of the network in places previously unavailable or unprofitable. In the case of balancing production and demand, a photovoltaic installation can be an effective and sufficient source of electricity that will cover the annual electricity demand generated by the heat pump installation, when it is used for both heating and cooling. The alternating demand of facilities for heating and cooling energy, caused by changes in the seasons, suggests potential for using seasonal cold and heat storage.

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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.

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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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Business models for district heating networks

Sustainable Urban Energy Policy ◽

10.4324/9781315739533-6 ◽

2015 ◽

pp. 113-136

Author(s):

David Hawkey ◽

Janette Webb

Keyword(s):

Business Models ◽

District Heating ◽

Heating Networks

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BUILDINGS AS ACTIVE COMPONENTS FOR GRID STABILITY

Journal of Green Building ◽

10.3992/1943-4618.12.4.21 ◽

2017 ◽

Vol 12 (4) ◽

pp. 21-34

Author(s):

Friedrich Sick ◽

Ralph Füger

Keyword(s):

Capital Investment ◽

Heat Storage ◽

Reactive Power ◽

District Heating ◽

Energy Transition ◽

Heat Pumps ◽

Raw Material ◽

Analysis Tool ◽

Active Components ◽

Massive Structure

A successful energy transition depends on storage options in order to ensure power supply stability under a fluctuating generation of a growing share of renewable energies (RE). Battery storage is expensive and raw material intensive and therefore not suitable as a sole solution. Surplus electricity may easily be converted to heat, which can be stored inexpensively for a short term. With such simple Power-to-Heat or P2H solutions, lack of electric power cannot be offset by conventional heat storage. However, if a building or an urban quarter is heated by means of cogeneration, so-called Combined Heat and Power (CHP), or heat pumps (HP), the operation can be adjusted in such a way, that the building itself, i.e. its massive structure, serves as heat storage. Electricity generation and consumption is adjusted to the requirements of the grid (reactive power control). For the supply of a Berlin quarter, built in the 1950s and equipped with a district heating network and a CHP plant, the feasibility of the concept could be proved using dynamic building simulation as the analysis tool. Sixteen percent of the total heating consumption may useably be stored and extracted from the building structure. In absolute numbers: 73 MWh/a heat can be buffered corresponding to 34 MWh/a balancing electricity. For each square meter of living area, 3.7 kWh electrical balancing energy can be buffered in the building's thermal storage capacity. Nothing else is required than a re-programming of heating and possibly cooling controls. No capital investment is needed. Well insulated and more massive structures could show a proportion of 27% of such shifted heat.

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Electricity market options for heat pumps in rural district heating networks in Austria

Energy ◽

10.1016/j.energy.2019.116875 ◽

2020 ◽

Vol 196 ◽

pp. 116875 ◽

Cited By ~ 4

Author(s):

O. Terreros ◽

J. Spreitzhofer ◽

D. Basciotti ◽

R.R. Schmidt ◽

T. Esterl ◽

...

Keyword(s):

Electricity Market ◽

District Heating ◽

Heat Pumps ◽

Rural District ◽

Heating Networks

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On the Participation of Power-To-Heat Assets in Frequency Regulation Markets—A Danish Case Study

Energies ◽

10.3390/en13184608 ◽

2020 ◽

Vol 13 (18) ◽

pp. 4608

Author(s):

Florin Iov ◽

Mahmood Khatibi ◽

Jan Dimon Bendtsen

Keyword(s):

Power Distribution ◽

Data Exchange ◽

District Heating ◽

Distribution Networks ◽

Heat Pumps ◽

Green Energy ◽

Frequency Regulation ◽

Ancillary Service ◽

Architecture Model ◽

Service Markets

Due to the new green energy policies, district heating companies are being increasingly encouraged to exploit power-to-heat assets, e.g., heat pumps and electric boilers, in their distribution networks besides the traditional central combined heat and power units. The increased utilization of these assets will generate a more complex interaction between power distribution grids and district heating networks including markets for provision of ancillary services. Enabling the participation of power-to-heat units in the ancillary service markets, e.g., frequency reserves, may increase the revenue streams for assets’ owners. However, some technical challenges must first be addressed, including optimization of portfolios of assets that accounts for ancillary service markets, new coordination and operational schemes for portfolio of assets, increase data exchange and interactions with transmission system operators, and new local control schemes for units. This paper proposes a systematic model based design approach for assessment of provision of frequency regulation by power-to-heat assets using the smart grid architecture model. The proposed approach is demonstrated in a Real-Time Control Hardware-in-the-Loop laboratory environment.

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Optimized Layouts of Borehole Thermal Energy Storage Systems in 4th Generation Grids

Energies ◽

10.3390/en13174405 ◽

2020 ◽

Vol 13 (17) ◽

pp. 4405 ◽

Cited By ~ 1

Author(s):

Hoofar Hemmatabady ◽

Julian Formhals ◽

Bastian Welsch ◽

Daniel Otto Schulte ◽

Ingo Sass

Keyword(s):

Energy Storage ◽

Thermal Energy ◽

Thermal Energy Storage ◽

Heating Temperature ◽

Storage System ◽

District Heating ◽

Temperature Shift ◽

Heat Pumps ◽

Optimal Designs ◽

Practical Implementation

Borehole thermal energy storage (BTES) systems are a viable option to meet the increasing cooling demand and to increase the sustainability of low-temperature district heating and cooling (DHC) grids. They are able to store the rejected heat of cooling cycles on a seasonal basis and deliver this heat during the heating season. However, their efficient practical implementation requires a thorough analysis from technical, economic and environmental points of view. In this comparative study, a dynamic exergoeconomic assessment is adopted to evaluate various options for integrating such a storage system into 4th generation DHC grids in heating dominated regions. For this purpose, different layouts are modeled and parameterized. Multi-objective optimization is conducted, varying the most important design variables in order to maximize exergetic efficiency and to minimize levelized cost of energy (LCOE). A comparison of the optimal designs of the different layouts reveals that passive cooling together with maximizing the heating temperature shift, accomplished by a heat pump, lead to optimal designs. Component-wise exergy and cost analysis of the most efficient designs highlights that heat pumps are responsible for the highest share in inefficiency while the installation of BTES has a high impact in the LCOE. BTES and buffer storage tanks have the lowest exergy destruction for all layouts and increasing the BTES volume results in more efficient DHC grids.

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