Energy efficiency of smart windows made of photonic crystal

Yuan

2019

Energies

The increasing demand for applying energy performance contracting (EPC) for urban energy conservation has resulted in a significant amount of publications over the past decade. This study tries to identify future research trends in the subject of EPC through analyzing 127 journal papers published from 2008 to 2018. Based on the analysis and discussion of the EPC research, several main research trends were identified. The research results reveal an increasing research interest in EPC over the period. The findings imply that case study is the major research method and descriptive analysis and statistical analysis are primarily used for data analysis. In addition, EPC research in the past decade focused on five major research topics, which are ‘implementation of EPC projects’, ‘EPC mechanism and business models’, ‘decision-making in EPC projects’, ‘Energy Service Companies (ESCOs) in EPC projects’, and ‘risk management in EPC projects’. Based on the five research topics, future research trends and directions in EPC were identified as well. The findings of this study can be informative and valuable for guiding future research in EPC, and are particularly helpful for researchers who are keen to open a new window of investigating EPC issues worldwide.

Section: Research Trend Of "Implementation Of Epc Projects"mentioning

confidence: 99%

Section: Research Trend Of "Implementation Of Epc Projects"mentioning

confidence: 99%

Promoting Energy Performance Contracting for Achieving Urban Sustainability: What is the Research Trend?

Yuan

2019

Energies

“…Studies have proved the important role of EPC in improving the energy efficiency in various sectors, such as in the building retrofit field [2,8,74], real estate field [25,81,82], and in the iron system, steel system, and public light system [3,83]. However, how to effectively measure and verify (M&V) the energy-saving quantity achieved by EPC projects has been ignored, though some of the above studies (e.g., [2,25] acknowledged that M&V is critical for EPC project implementation.…”

Section: Lack Of Effective Measurement and Verification Of Energy Savmentioning

confidence: 99%

A Bibliometric Analysis of Energy Performance Contracting Research from 2008 to 2018

Yuan

2019

Sustainability

Increasing research interests in energy performance contracting (EPC) has resulted in a large number of publications over the past decade. However, very limited attempts have been made to map the global research in this area. To identify the state of the field and trends in EPC research, the VOSviewer software package was used to conduct a series of content analyses and examine global patterns among publications, including the distribution of core authors and institutions, high-frequency categories and keywords, journal and author contributions, highly cited papers, etc. Based on a systematical and deeply qualitative analysis on the 127 identified papers, five mainstream research topics in EPC were summarized, covering implementations of EPC, mechanisms for effective EPC projects, stakeholder behaviors and decisions in EPC projects, energy service company (ESCO) in EPC projects, and risk management in EPC. In addition, six main research gaps in EPC were identified, including lack of effective measurement and verification of energy savings, limited studies on EPC projects in the residential sector, ineffective mechanisms to ensure post-EPC energy-saving, limited research on the dual relationships among EPC project stakeholders, how to improve the energy users’ (EU) attitudes/cognitions toward ESCO/EPC, and lack of effective mechanisms to prevent risks in EPC projects. Furthermore, based on the current EPC research topics and research gaps in EPC, six potential research directions in EPC in future were also explored, which are how to develop effective methods for measuring and verifying energy efficiency?, EPC diffusion issues in the residential sector, effective mechanisms to ensure post-EPC energy-saving, effects of cooperative and competitive relationships between EU and ESCO on the performance of EPC projects, how to improve the EU’s attitudes/cognitions toward ESCO/EPC, and how to deal with risks in EPC projects. The outcomes would be useful for understanding the latest development of global EPC research and guiding future research in the subject.

“…Stimuli-responsive photonic polymer coatings are able to change color in response to an external stimulus [1]. These "smart" coatings have potential applications in energy-regulating windows [2,3], food safety labels, healthcare products and smart packaging [1]. Many photonic systems have been developed using cholesteric liquid crystals (Ch-LCs) [4].…”

Section: Introductionmentioning

confidence: 99%

Polymer Stabilized Cholesteric Liquid Crystal Siloxane for Temperature-Responsive Photonic Coatings

Lub

Schenning

et al. 2020

IJMS

Temperature-responsive photonic coatings are appealing for a variety of applications, including smart windows. However, the fabrication of such reflective polymer coatings remains a challenge. In this work, we report the development of a temperature-responsive, infrared-reflective coating consisting of a polymer-stabilized cholesteric liquid crystal siloxane, applied by a simple bar coating method. First, a side-chain liquid crystal oligosiloxane containing acrylate, chiral and mesogenic moieties was successfully synthesized via multiple steps, including preparing precursors, hydrosilylation, deprotection, and esterification reactions. Products of all the steps were fully characterized revealing a chain extension during the deprotection step. Subsequently, the photonic coating was fabricated by bar-coating the cholesteric liquid crystal oligomer on glass, using a mediator liquid crystalline molecule. After the UV-curing and removal of the mediator, a transparent IR reflective polymer-stabilized cholesteric liquid crystal coating was obtained. Notably, this fully cured, partially crosslinked transparent polymer coating retained temperature responsiveness due to the presence of non-reactive liquid-crystal oligosiloxanes. Upon increasing the temperature from room temperature, the polymer-stabilized cholesteric liquid crystal coating showed a continuous blue-shift of the reflection band from 1400 nm to 800 nm, and the shift was fully reversible.