| 1. |
- Liu, L., et al.
(author)
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Forecasting the occurrence of extreme electricity prices using a multivariate logistic regression model
- 2022
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In: Energy. - : Elsevier Ltd. - 0360-5442 .- 1873-6785. ; 247
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Journal article (peer-reviewed)abstract
- Extreme electricity prices occur with a higher frequency and a larger magnitude in recent years. Accurate forecasting of the occurrence of extreme prices is of great concern to market operators and participants. This paper aims to forecast the occurrence probability of day-ahead extremely low and high electricity prices and investigate the relative importance of different influencing variables. The data obtained from the Australian National Electricity Market (NEM) were employed, including historical prices (one day before and one week before), reserve capacity, load demand, variable renewable energy (VRE) proportion and interconnector flow. A Multivariate Logistic Regression (MLgR) model was proposed, which showed good forecasting capability in terms of model fitness and classification accuracy with different thresholds of extreme prices. In addition, the performance of the MLgR model was verified by comparing with two other models, i.e., Multi-Layer Perceptron (MLP) and Radical Basis Function (RBF) neural network. Relative importance analysis was performed to quantify of the contribution of the variables. The proposed method enriches the theories of electricity price forecast and advances the understanding of the dynamics of extreme prices. By applying the model in practice, it will contribute to promoting the management of operation and establishment of a robust energy market.
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| 2. |
- Lyu, Yuexia, et al.
(author)
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Techno-economic evaluation of an optical fiber based hybrid solar lighting system
- 2020
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In: Energy Conversion and Management. - : Elsevier Ltd. - 0196-8904 .- 1879-2227. ; 225
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Journal article (peer-reviewed)abstract
- Optical fiber solar lighting systems are an appealing approach for illumination applications with the aim of reducing energy consumption and greenhouse gas emissions from artificial lighting. This study presented the design, construction and assessment of an optical fiber based hybrid solar lighting system for illumination of interior spaces. The proposed system combines the features of optical fiber daylighting technology and photovoltaic power generation technology. Specifically, a secondary light concentrator was designed to improve the uniformity of flux distribution and solve the overheating problem of PMMA fibers. The technical feasibility of the hybrid solar lighting system was validated using the fabricated prototype in a 5 m2 darkroom during a whole day test. Experimental results showed that, an average illuminance of 105 lx at a distance of 2 m from the end of optical fiber bundle was achieved, saving 316.82 kWh and reducing 251.24 kg carbon dioxide emissions every year in the studied case. Finally, cost analysis of the proposed hybrid solar lighting system was carried out and compared with three conventional lighting systems. The total payback period of the hybrid solar lighting system was 3.7 years and further reduced to 1.7 years in mass production. In the studied case, the hybrid solar lighting system was economically competitive after 2 years and 12 years of operation in comparison with a 100 W incandescent bulb lighting system and a 30 W T8 fluorescent lamp lighting system, respectively.
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| 3. |
- Su, Difei, et al.
(author)
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Market Analysis of Natural Gas for District Heating in China
- 2015
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In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 75, s. 2713-2717
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Journal article (peer-reviewed)abstract
- Natural gas (NG) is expected to be used broadly in China to replace coal in district heating sector in order to reduce air pollution due to coal burning. However, it is difficult for natural gas to penetrate district heating market due to its relatively high cost. In the present study, a market simulation method is proposed to find the marginal conditions and policy to promote natural gas utilization for district heating. In the proposed method, technology improvement, pricing mechanism, carbon tax and user's pricing response are considered. The prerequisite of the market simulation is that the heating expenses of end-users won't increase and the benefit of heat producers won't decrease when using NG to replace coal. Based on the obtained analysis results, gas pricing revolution, heating pricing revolution and carbon tax mechanism are discussed in order to promote the gas-fired heating through market mechanism.
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| 4. |
- Wei, H., et al.
(author)
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Optimization of server water cooling system operating conditions based on minimum energy consumption analysis
- 2020
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In: Energy Proceedings. - : Scanditale AB.
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Conference paper (peer-reviewed)abstract
- To improve data center thermal management, a water cooling system based on the cooling tower of data center with thermal power of 4.8 kW is introduced. A fin-type water-cooled heat sink is taken to cool chip in the server cabinet. Aiming to realize the minimum energy consumption of the water cooling system, and the optimization analysis on the cooling water working condition is carried under different safe chip temperature with aid of TRNSYS software. The results show that when taking safe chip temperature of 70°C, the minimum power usage effectiveness (PUE) value of approximately 1.097 is yielded at these optimal case: inlet temperature of secondary cooling water of 20°C, and the primary and secondary cooling water flow rates of 9.207 L/min and 6.108 L/min, respectively. Finally, the fitting correlation equations of optimal parameters for different safe chip temperature are given to guide cooling system design.
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