This paper describes a new digital current sharing method for parallel interleaved dc-dc converters. The difference between sensed inductor values can cause unequal distribution in the converters even though they are controlled by same average mode controller with common reference. To overcome this problem, simple algorithm using input voltage ripple is proposed. calculates required reference adjustment value only information. No additional sensing circuit required. proposed achieves equal...

Abstract The piezoelectric nanogenerator (PENG) has the potential to become a promising power supply for monitoring and sensors in Internet of Things (IoT) systems through wireless networks. In order further increase utilization energy harvesters an IoT system, we introduce novel approach that greatly enhances output performances by employing layer-by-layer (LbL) method. Poly(vinylidenefluoride-co-trifluoroethylene) (PVDF-TrFE) polymer film, which properties mechanical flexibility, was used...

Energy storage systems are an effective solution to manage the intermittency of renewable energies, balance supply, and demand. Numerous studies recommend adopting a shared energy system (ESS) as opposed multiple single ESSs because their high prices inefficiency. Thus, this study examines in grid-connected microgrid. By modifying power outputs resources, work intends implement economic dispatch ESS order satisfy lower overall cost electricity. In context, optimization problem was formulated...

We present a simple method for fabricating robust dry adhesives by coating soft polydimethyl siloxane (PDMS) thin layer on rigid backbone micropillars of polyurethane acrylate (PUA). These core–shell type demonstrated enhanced durability both in normal and shear adhesion over more than 100 cycles attachment detachment. Relatively strong (∼11.4 N cm−2) (∼15.3 forces were observed, which similar to or even larger those homogeneous PDMS micropillars. A theoretical model based beam deflection...

An adequate window system is one of the most important retrofit strategies for effective energy conservation a building, because U-value and solar heat gain coefficient windows have enormous impact on heating cooling loads buildings. Therefore, this paper presents methods improving efficiency existing residences that various sizes envelope insulations, through using optimal values. Furthermore, strategy has been standardized analysis correlation between properties retrofitted saving rates....

This study proposes the air–surface temperature ratio (ASTR) method as an in situ measurement to rapidly and accurately measure wall U-values existing houses. Herein, were measured applying heat flow meter (HFM) of ISO 9869-1 ASTR method. The results obtained using HFM methods compared, relative error rate accuracy measurements analyzed. aging rates compared analyzed by comparing them with before after installation retrofit insulation. Subsequently, was used analyze U-value according number...

Composites were prepared by blending PVDF-TrFE/PEDOT:PSS (weight ratio: 0–60%). The ferroelectric characteristics of PVDF-TrFE can be enhanced adding PEDOT:PSS.

Abstract Heating, ventilation, and air conditioning (HVAC) systems account for one-third of the total energy consumption in office buildings. The use airflow measurements to control operation HVAC can reduce consumption; thus, a sensor capable monitoring duct system is critical. Triboelectric nanogenerators (TENGs) be utilized as self-powered sensors airflow-driven TENGs (ATENGs) sensors. By employing ferroelectric materials surface modifications, charges increased. In this study,...

One way to achieve carbon neutrality is by improving the energy performance of existing buildings, which requires accurate measurements. In particular, measurement heat loss coefficient (HLC) critical because a building envelope an important parameter analysis. The international standard for measuring HLC flow meter (HFM) method in ISO 9869-1, can be used obtain at representative points on envelope. However, this approach does not account thermal bridges, means that adding up HLCs obtained...

Artificial lighting in office buildings typically requires 30% of the total energy consumption building, providing a substantial opportunity for savings. To reduce consumed by indoor lighting, we propose sensor-less light-emitting diode (LED) dimming system using daylight harvesting. In this study, used light simulation software to quantify and visualize daylight, analyzed correlation between photovoltaic (PV) power generation illumination an with integrated PV system. addition, calculated...

Temperature restriction in indoor environment is a simple way of saving energy; however, it may cause discomforts to the people such an environment. The discomfort aggravated when environments different rooms cannot be controlled individually. Furthermore, intensified during intermittent seasons. Thermal comfort estimated by Predicted Mean Vote (PMV) model based on six parameters. This complex procedure and has limitations because number measurement indices have known. Hence, we analyzed...

This paper reports on a feasibility study conducted to improve the in situ measurement accuracy of air-surface temperature ratio (ASTR) method. The measured relative error rate was analyzed using ISO 6946 [7.69 W/(m2·K)] and Korea Energy Saving Design Standard [9.09 indoor total surface heat transfer coefficients. according fluctuations outdoor data. obtained standard about 6.3% that 9.5%. for less than 1 K 4.62% temperatures greater 14.31%. results confirmed cause ASTR. It also found latter...

Neural network models are data-driven and effective for predicting interpreting nonlinear or unexplainable physical phenomena. This study collected building information heating energy consumption data from 16,158 old houses, selected key input variables that affect the based on datasets, developed a deep neural (DNN) model showed highest accuracy prediction of in an house. As result, 11 were selected, optimal DNN was developed. (R2 = 0.961) when number hidden layers five neurons 22. When...

The amount of heat lost through the envelope a building is one most important variables that affects energy performance evaluation house. In addition, it especially to estimate and accurately diagnose produced by windows. Korea, windows’ U-values reflect building’s initial design values thermal characteristics determine an existing building, factor can overestimate building. Therefore, there need for field measurement method measure total U-value windows in This study provides quantitatively...

This paper describes a power control scheme to improve the performance of fuel cell-battery hybrid source for residential application. The proposed includes strategy flow cell system and digital technique front-end dc-dc converter cell. enables operate within high efficiency region defined by polarization curve A dual boost with is applied as output power. employs moving-average filter into its voltage feedback loop cancel low frequency harmonic current drawn from then limits limit using...

In relation to recent attention focused on the use of energy by lighting, there is a large potential for commercial buildings save in this respect. The energy-saving bulbs or dimming controls triggered daylight, not only enables lighting saving, but delivers cooling through reduction indoor heat production. study, we examine evaluating saving methods and effect using dimmer with control method, which can both maximize load during summer energy. Results show that total from reference building...