A novel demand-responsive control strategy for district heating systems, featuring return temperature reduction

Tol, Hakan İbrahim; Desmedt, Johan; Salenbien, Robbe

doi:10.1016/j.enbenv.2020.05.001

Cited by 19 publications

(7 citation statements)

References 23 publications

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“…DH I = 0.47ε + 0.29 f c + 0.24 f b (24) The analytic hierarchy process (AHP) method provides a rational framework for a needed decision by quantifying its criteria and alternative options and for relating those elements to the overall goal. RCA is an advanced method developed from the conventional AHP, which can be used to determine subjective weights.…”

Section: Comprehensive Performancementioning

confidence: 99%

“…In contrast, there is virtually no analysis of heat-oriented CHP systems that preferentially satisfy building thermal demand. In light of the characteristics, such as the fluctuation in the heating load [24], the CHP systems in which power capacity is determined by heat supply should be analyzed based on the exergy methods. Third, the thermodynamic, economic, and environmental performances of CHP systems were separately evaluated.…”

Section: Introductionmentioning

confidence: 99%

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An Evaluation Method of Comprehensive Performance of Retrofitted CHP District Heating Systems

Chong

Zhou

et al. 2023

Energies

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There is a big wave in China of retrofitting single-purpose coal-fired systems for district heating into heat-oriented combined heat and power (CHP) systems to save energy. Back-pressure steam turbines (BPSTs) and extraction steam turbines (ESTs) are both common in retrofitted systems, but contrastive analyses of their effects on the systems’ operation performance are lacking. Moreover, comprehensive evaluation methods of the retrofitted systems remain unknown. In this paper, exergy, exergoeconomic, and exergoenvironmental analyses were conducted to evaluate the thermodynamic, economic, and environmental performances of two real CHP systems: system A using a BPST and system B using an EST. Additionally, a new multi-criteria evaluation method based on rank correlation analysis was proposed for the retrofitted system. The results show that system A is better than system B in thermodynamic and environmental aspects but poorer in the economic aspect. Overall, the multi-criteria evaluation result indicates that system A has a better comprehensive performance than system B. Therefore, the BPST has a better effect than the EST on the retrofitted CHP system for district heating in this study. The findings could provide a reference point for retrofitting work in the future.

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Section: Comprehensive Performancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Evaluation Method of Comprehensive Performance of Retrofitted CHP District Heating Systems

Chong

Zhou

et al. 2023

Energies

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“…It is common practice to use weather-compensation controls both at the DH level and the substation [126]. The ability to reduce the operating temperature in well-functioning space heating systems enables DH operator to reduce temperatures in the DH.…”

Section: Design and Operating Temperature In Other Countriesmentioning

confidence: 99%

Challenges for the Transition to Low-Temperature Heat in the UK: A Review

2021

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To reach net-zero emissions by 2050, buildings in the UK need to replace natural gas boilers with heat pumps and district heating. These technologies are efficient at reduced flow/return temperatures, typically 55/25 °C, while traditional heating systems are designed for 82/71 °C, and an oversized heating system can help this temperature transition. This paper reviews how heating systems have been sized over time in the UK and the degree of oversizing in existing buildings. It also reviews if lessons from other countries can be applied to the UK’s building stock. The results show that methods to size a heating system have not changed over time, but the modern level of comfort, the retrofit history of buildings and the use of margin lead to the heating system being generally oversized. It is not possible to identify a specific trend by age, use or archetype. Buildings in Scandinavia have a nascent readiness for low-temperature heat as they can use it for most of the year without retrofit. Limitations come primarily from the faults and malfunctions of such systems. In the UK, it is estimated that 10% of domestic buildings would be ready for a supply temperature of 55 °C during extreme external conditions and more buildings at part-load operation. Lessons from Scandinavia should be considered with caution. The building stock in the UK generally underperforms compared to other EU buildings, with heating systems in the UK operating at higher temperatures and with night set-back; the importance of providing a low-return temperature does not exist in the UK despite being beneficial for condensing boiler operation. Sweden and Denmark started to develop district heating technologies with limitations to supply temperatures some 40 years ago whereas the UK is only just starting to consider similar measures in 2021. Recommendations for policy makers in this context have been drawn from this review in the conclusions.

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“…In order to increase the efficiency of DHNs, faults in customer stations have to be identified. A new fault detection method has been presented which works with the temperature difference signature [11]. The method presented is fast and inexpensive, and therefore feasible in practice.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of a District Heating Substation as Part of a Low-Investment Optimization Strategy for District Heating Systems

2021

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In an ongoing project, low-investment measures for the optimization of district heating systems are analyzed. The optimization strategies are collected in a catalog, which is the core of a guideline. The application of this guideline is demonstrated using two concrete district heating networks as examples. In this study, the improvement of an analog controlled district heating substation by an electronic controller is investigated. High supply temperatures and heat losses are often a challenge in district heating networks. The district heating substations have a major influence on the network return temperatures. The comparison of the two substation setups with analog and electronic controllers is carried out by laboratory measurement. It can be shown that the return temperatures can be reduced by an average of 20 K in winter and transition, as well as 16 K in summer. The district heating network losses are calculated for one of both specific district heating networks. They are calculated from the ratio of network losses to generated energy. The generated energy is the sum of network losses and consumer demand. The thermal losses of the network can be reduced by 3%. The volume flow in the heating network can be reduced to a quarter. Therefore, the pumping energy requirement drops sharply since these changes cubically affect the volume flow.

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A novel demand-responsive control strategy for district heating systems, featuring return temperature reduction

Cited by 19 publications

References 23 publications

An Evaluation Method of Comprehensive Performance of Retrofitted CHP District Heating Systems

An Evaluation Method of Comprehensive Performance of Retrofitted CHP District Heating Systems

Challenges for the Transition to Low-Temperature Heat in the UK: A Review

Enhancement of a District Heating Substation as Part of a Low-Investment Optimization Strategy for District Heating Systems

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