A Study on Urban Heating System Flexibility: Modeling and Evaluation

Abstract This study investigates the urban heating system (UHS) by taking a look at the heat transportation flexibility of the system. We propose the heating system flexibility (HSF) concept to represent UHS’s capability of meeting the heating demand under different operation conditions during the heating season and give out the corresponding evaluation method. Based on the evaluation method, we investigate the impact of heating network enhancement measures upon HSF by taking a real UHS in Beijing as a demo site. We pick network-wise topological change (extra pipe) and booster pump installation as two representative renovation measures. When an extra pipe close to end-user is introduced to the network, the average flexibility increases but the median flexibility drops. The results show that the introduction of the extra pipe does not reduce the hydraulic imbalance among different substations. A booster pump is more suitable for improving local substation HSF, although such a measure is only effective to a portion of the substations. Overall, the concept of HSF has the potential of being used as an important criterion in the design, operation, and control of UHS and other energy systems.

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A Study on Urban Heating System Flexibility: Modeling and Evaluation

ASME 2019 13th International Conference on Energy Sustainability ◽

10.1115/es2019-3863 ◽

2019 ◽

Author(s):

Jiaying Chen ◽

Wei Huang ◽

Wei Zhong ◽

Yi Zhou ◽

Xiaojie Lin

Keyword(s):

Topological Structure ◽

Large Scale ◽

Evaluation Method ◽

Heating System ◽

Structure Change ◽

End User ◽

Quantification Method ◽

New Perspective ◽

And Control ◽

The Impact

Abstract This study develops a new perspective of analyzing urban heating system (UHS) by taking a looking at the heat transportation flexibility of the system. We proposed the heating system flexibility (HSF) concept to represent UHS’s capability of delivering heat to the substations (and the buildings) under different operation scenarios of valves and pumps. We also give out the corresponding evaluation method. Based on the proposed ideal and its quantification method, we take a real UHS as an example to show the effectiveness of HSF by investigating the impact of heating network topological structure change. When a topological change close to end user is introduced, the average flexibility increases but the median flexibility drops. We find that system-wide topological structure change such as new pipeline does not solve the imbalance of HSF among substations. Overall, the concept of HSF has the potential of being used as an important criterion in the design, operation, and control of future large-scale complex multi-source UHS.

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Current predictive controller for high frequency resonant inverter in induction heating

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v10i1.pp255-264 ◽

2020 ◽

Vol 10 (1) ◽

pp. 255 ◽

Cited By ~ 2

Author(s):

Azzedine Khati ◽

Abdelkader Kansab ◽

Rachid Taleb ◽

Houari Khouidmi

Keyword(s):

Induction Heating ◽

High Frequency ◽

Heating System ◽

Current Loop ◽

Modeling And Control ◽

Resonant Inverter ◽

Predictive Controller ◽

High Frequency Resonance ◽

And Control ◽

The Impact

In the context of this article, we are particularly interested in the modeling and control of an induction heating system powered by high frequency resonance inverter. The proposed control scheme comprises a current loop and a PLL circuit. This latter is an electronic assembly for slaving the instantaneous phase of output on the instantaneous input phase, and is used to follow the rapid variations of the frequency.To further improve the transient dynamics of the studied system and in order to reduce the impact of measurement noise on the control signal, a generalized predictive control has been proposed to control the current of the inductor. We discussed the main steps of this command, whose it uses a minimization algorithm to obtain an optimal control signals, its advantages are: its design is simple, less complexity and direct manipulation of the control signal.The results have shown the effectiveness of the proposed method, especially in the parameters variation and/or the change of the reference current.

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INFLUENCE OF APARTMENTS’ MODERNIZATION ON THE TEMPERATURES OF HEATING SYSTEM IN THE BUILDING

Mokslas - Lietuvos ateitis ◽

10.3846/mla.2021.15275 ◽

2021 ◽

Vol 13 (0) ◽

pp. 1-6

Author(s):

Giedrius Šiupšinskas ◽

Juozas Bielskus ◽

Artur Rogoža

Keyword(s):

Heat Carrier ◽

Heating Temperature ◽

Heating System ◽

System Model ◽

Space Heating ◽

Heating Season ◽

Heating Device ◽

Carrier Temperature ◽

Hourly Data ◽

The Impact

When modernizing apartment buildings, heating appliances are replaced or old ones are left, high thermal temperatures are usually maintained, thus limiting the increase in the DH system’s efficiency. In the article, in order to evaluate the impact of the reduced thermal temperature of the building on space heating when the radiator area remains constant, 3 alternatives have been analyzed. They include cases when after the building modernization old heating appliances are left, but the temperature of the heat carrier is reduced up to 60/40/20 °C in one case or even up to 45/25/20 in another alternative. There has also been examined the possibility of reducing the heat carrier temperature of the heating system without modernization of the building. An hourly data analysis of the heating system model for two typical months of the heating season has been performed. The analysis shows that after the modernization of the building, when heating device areas are left the same, the existing heating temperature can be reduced to 60/40/2020 °C.

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Variable-Load Heat Pumps: Impact of the Design and Control Parameters on the Actual Operation Conditions

TECNICA ITALIANA-Italian Journal of Engineering Science ◽

10.18280/ti-ijes.652-434 ◽

2021 ◽

Vol 65 (2-4) ◽

pp. 371-377

Author(s):

Alice Mugnini ◽

Gianluca Coccia ◽

Fabio Polonara ◽

Alessia Arteconi

Keyword(s):

Control Strategies ◽

Residential Building ◽

Energy Performance ◽

Heat Pumps ◽

Design Parameters ◽

Variable Load ◽

Actual Performance ◽

Operation Conditions ◽

And Control ◽

The Impact

Nowadays heat pumps (HPs) represent the main alternative to traditional heating systems for the transition to nearly zero-energy buildings. Though HPs are a well-known technology, the estimation of their actual energy performance is still under discussion. Indeed, the proper choice of the HP design parameters (e.g. size, rated supply temperature) and the adopted control strategy can assume a paramount role to cover the mismatch between declared and actual performance of the system. Objective of this work is to analyze this mutual dependence in an operating system to provide guidelines for the design of a residential heating system with a HP. Through a dynamic energy simulation tool, a variable-load air-to-water HP is used to cover the thermal demand of a residential building. The effect of the reciprocal influence of different design choices (e.g. rated heating capacity or design supply temperature) and control strategies (e.g. climatic regulation) is analyzed by simulating different scenarios. To complete the evaluation, the impact of a thermal energy storage is also assessed. The study allows to identify guidelines for the design of different system configurations and results seem to confirm the impact of the investigated parameters on the seasonal performance of the system.

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Analysis of the Environmental Effects of the Clean Heating Policy in Northern China

Sustainability ◽

10.3390/su13126695 ◽

2021 ◽

Vol 13 (12) ◽

pp. 6695

Author(s):

Siyu Chen ◽

Hong Chi

Keyword(s):

Quality Improvement ◽

Energy Use ◽

Northern China ◽

Control Group ◽

Heating Season ◽

Difference Model ◽

Air Quality Improvement ◽

And Control ◽

The Impact ◽

Gas Supply

This article estimates the impact of the “Clean Heating Plan in Northern China (2017–2021)” on air quality improvement. It is a significant policy to promote the clean heating rate in Northern China, while there is limited research into its effects. We used a difference-in-difference model to qualify the effects of this policy on the “2 + 26” cities. For this, we controlled factors such as economy, energy use, afforestation level, and weather. We found that: (1) the clean heating plan makes the “2 + 26” cities’ AQI index, PM2.5, PM10, NO2, and O3 significantly decrease; (2) the concentrations of SO2 and CO increase. After adjusting the treatment group and control group, the results are still robust. We believe that the rise of SO2 is due to the shortage of natural gas supply in the 2017–2018 heating season in China, which led to the blockage of clean heating. Therefore, in promoting clean heating in Northern China, it is necessary to strengthen the estimation of heating demand, fully consider the energy structures of different regions, and implement the “reform by gas”.

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Suppressed, but Not Forgotten

Swiss Journal of Psychology ◽

10.1024/1421-0185/a000033 ◽

2011 ◽

Vol 70 (1) ◽

pp. 5-11 ◽

Cited By ~ 8

Author(s):

Beat Meier ◽

Anja König ◽

Samuel Parak ◽

Katharina Henke

Keyword(s):

Memory Trace ◽

Thought Suppression ◽

Test Phase ◽

Indirect Test ◽

Final Test ◽

Test Experiment ◽

And Control ◽

Cue Words ◽

The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

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Research Participation Experiences of Informants of Suicide and Control Cases

Crisis ◽

10.1027/0227-5910/a000025 ◽

2010 ◽

Vol 31 (5) ◽

pp. 238-246 ◽

Cited By ~ 9

Author(s):

Paul W. C. Wong ◽

Wincy S. C. Chan ◽

Philip S. L. Beh ◽

Fiona W. S. Yau ◽

Paul S. F. Yip ◽

...

Keyword(s):

Ethical Issues ◽

Research Participation ◽

Self Report ◽

Initial Contact ◽

Psychological Autopsy ◽

Autopsy Study ◽

The People ◽

And Control ◽

The Impact

Background: Ethical issues have been raised about using the psychological autopsy approach in the study of suicide. The impact on informants of control cases who participated in case-control psychological autopsy studies has not been investigated. Aims: (1) To investigate whether informants of suicide cases recruited by two approaches (coroners’ court and public mortuaries) respond differently to the initial contact by the research team. (2) To explore the reactions, reasons for participation, and comments of both the informants of suicide and control cases to psychological autopsy interviews. (3) To investigate the impact of the interviews on informants of suicide cases about a month after the interviews. Methods: A self-report questionnaire was used for the informants of both suicide and control cases. Telephone follow-up interviews were conducted with the informants of suicide cases. Results: The majority of the informants of suicide cases, regardless of the initial route of contact, as well as the control cases were positive about being approached to take part in the study. A minority of informants of suicide and control cases found the experience of talking about their family member to be more upsetting than expected. The telephone follow-up interviews showed that none of the informants of suicide cases reported being distressed by the psychological autopsy interviews. Limitations: The acceptance rate for our original psychological autopsy study was modest. Conclusions: The findings of this study are useful for future participants and researchers in measuring the potential benefits and risks of participating in similar sensitive research. Psychological autopsy interviews may be utilized as an active engagement approach to reach out to the people bereaved by suicide, especially in places where the postvention work is underdeveloped.

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