LowExTra - Feasibility of a Multi-Conductor District Heating System

Dunkelberg, Elisa; Schneller, Andreas; Bachmann, Max; Kriegel, Martin

doi:10.1016/j.egypro.2018.08.207

Cited by 5 publications

(5 citation statements)

References 4 publications

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“…Another key indicator in the urban expansion of Energiewende is in the effort of decarbonizing urban heating and cooling and increasing the share of renewable heat and waste heat by developing and expanding new lowcarbon heating and cooling technologies [104,105]. This move is important because urban heating and cooling in Germany still largely depend on fossil fuels, and the share of renewable energy in heating and cooling was only 16.5%, despite the share of renewable energy in total power generation of 41.1% in 2021 [106].…”

Section: Solarization: Solar Heating and Coolingmentioning

confidence: 99%

Urban expansion of Energiewende in Germany: a systematic bibliometric analysis and literature study

Yang

2022

Energ Sustain Soc

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Background Despite Germany’s world leadership of Energiewende, there have been mounting challenges, such as the slowdown of German renewable energy growth since 2017, when the Merkel administration dramatically changed the German renewable energy promotion policy from feed-in tariffs to competitive auctions. These challenges pose important research questions about whether and how an emerging urban expansion of Energiewende can serve as a vital solution to counteract the challenges to the energy transition. Answering these research questions provides a unique opportunity to explore the academic and historic foundations of the energy transition and its urban expansion, the emerging events that exemplify urban expansion, and the viable solutions this growing trend of urban expansion might be able to provide to the challenges to the German energy transition. Methods This paper conducted visual and manual bibliometric analyses, examined the results of case studies, and reviewed secondary literature and data on urban expansion of German Energiewende. Results By analyzing the bibliometric and investigative results, this paper identified political, socioeconomic, and technological challenges to Energiewende and a new trend of solar energy expansion in German cities aimed at meeting Germany’s carbon neutrality targets by 2045. The new trend of the urban expansion of the German energy transition manifests itself in the focused research efforts on identifying the vast untapped potential on new building rooftop areas in most populous German cities and/or detached and two-family houses in Germany and the recent booming of building-related solar PV and heating mandates in German cities and states, the expanding solar heating and cooling systems, and the government policy support at various levels in this urban expansion through aggressively strengthening climate and renewable energy targets. Conclusions In search for answers to the recent challenges of Energiewende in Germany, this paper conducted both visual and manual bibliometric analyses and applied desk research and reviews of secondary literature and data. This paper found an emerging trend of the urban expansion of Energiewende, including the awareness of the vast potential and gap of urban solarization and the enhanced urban municipal policies, actors, actions, and accomplishments of exploiting this potential. These findings were based on academic knowledge on the German energy transition and contribute to expanding this academic knowledge. To help more effectively exploit the vast potential in solarizing all German cities, especially the largest ones, this study recommends that further research more closely track the progress of this trend and apply more quantitative tools and approaches in future tracking.

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Section: Solarization: Solar Heating and Coolingmentioning

confidence: 99%

Urban expansion of Energiewende in Germany: a systematic bibliometric analysis and literature study

Yang

2022

Energ Sustain Soc

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“…The Low Exergy (or LowEx) design emphasizes the application of thermal resources to the small-potential thermal demands of the built environment (heating, cooling, humidity control), the efficiency of heat pumps at maintaining small, useful temperature differences, and sequencing heat pumps to obtain larger temperature lifts [40,41]. LowEx has been extended to district scales [42]. Thermally Active Building Systems (TABS) emphasize the utility of hydronic thermal redistribution, activating thermal mass within the occupied regions of a building, and the efficiency benefits of transferring heat across the large surface areas that comprise indoor built spaces [43,44].…”

Section: Comparison To Alternative Building Energy Schemamentioning

confidence: 99%

Towards Energy-Positive Buildings through a Quality-Matched Energy Flow Strategy

et al. 2022

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Current strategies for net-zero buildings favor envelopes with minimized aperture ratios and limiting of solar gains through reduced glazing transmittance and emissivity. This load-reduction approach precludes strategies that maximize on-site collection of solar energy, which could increase opportunities for net-zero electricity projects. To better leverage solar resources, a whole-building strategy is proposed, referred to as “Quality-Matched Energy Flows” (or Q-MEF): capturing, transforming, buffering, and transferring irradiance on a building’s envelope—and energy derived from it—into distributed end-uses. A mid-scale commercial building was modeled in three climates with a novel Building-Integrated, Transparent, Concentrating Photovoltaic and Thermal fenestration technology (BITCoPT), thermal storage and circulation at three temperature ranges, adsorption chillers, and auxiliary heat pumps. BITCoPT generated electricity and collected thermal energy at high efficiencies while transmitting diffuse light and mitigating excess gains and illuminance. The balance of systems satisfied cooling and heating demands. Relative to baselines with similar glazing ratios, net electricity use decreased 71% in a continental climate and 100% or more in hot-arid and subtropical-moderate climates. Total EUI decreased 35%, 83%, and 52%, and peak purchased electrical demands decreased up to 6%, 32%, and 20%, respectively (with no provisions for on-site electrical storage). Decreases in utility services costs were also noted. These results suggest that with further development of electrification the Q-MEF strategy could contribute to energy-positive behavior for projects with similar typology and climate profiles.

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“…It is assumed that it is sensible for a given system to define a constant ratio between anergetic and exergetic costs. The "anergy-exergy cost ratio" is defined as: (7) From a thermodynamic perspective, the value of the ratio should be less than one for any application. How a substantiated value can be determined is discussed later.…”

Section: Allocation Of Costs To Exergy and Anergy By An "Anergy-exerg...mentioning

confidence: 99%

“…As it allows implementing an energy-efficient and carbon-free heating for apartment houses, several studies have been carried out to analyze low temperature district heating (e.g. [7], [8]).…”

Section: Description Of the Systemmentioning

confidence: 99%

Giving Anergy a Value by the Application of an Anergy-exergy Cost Ratio in Thermo-economic Analysis of Systems that Make Thermal Energy Available

Meyer¹,

Stadler²

2022

Atlantis Highlights in Engineering

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Techno-economic analysis that allocate costs to the energy flows of energy systems are helpful to understand the formation of costs within processes and to increase the cost efficiency. For the economic evaluation, the usefulness or quality of the energy is of great importance. In exergy-based methods, this is considered by allocating costs to the exergy instead of energy. As exergy represents the ability of performing work, it is often named the useful part of energy. In contrast, the anergy, the part of energy, which cannot perform work, is often assumed to be not useful. However, heat flows as used e.g. in domestic heating are always a mixture of a relative small portion of exergy and a big portion of anergy. Although of lower quality, the anergy is obviously useful for these applications. The question is, whether it makes sense to differentiate between exergy and anergy and take both properties into account for the economic evaluation. To answer this question, a new methodical concept based on the definition of an anergy-exergy cost ratio is compared to the commonly applied approaches of considering either energy or exergy as the basis for economic evaluation. These three different approaches for the economic analysis of thermal energy systems are applied to an exemplary heating system with thermal storages. It is shown that the results of the technoeconomic analysis can be improved by giving anergy an economic value and that the proposed anergy-cost ratio allows a flexible adaptation of the evaluation depending on the economic constraints of a system.

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LowExTra - Feasibility of a Multi-Conductor District Heating System

Cited by 5 publications

References 4 publications

Urban expansion of Energiewende in Germany: a systematic bibliometric analysis and literature study

Urban expansion of Energiewende in Germany: a systematic bibliometric analysis and literature study

Towards Energy-Positive Buildings through a Quality-Matched Energy Flow Strategy

Giving Anergy a Value by the Application of an Anergy-exergy Cost Ratio in Thermo-economic Analysis of Systems that Make Thermal Energy Available

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