The influence of solar panel roof on urban thermal environment and cooling energy demand during a heat wave event in 2017

2020 ◽  
Author(s):  
Yongwei Wang ◽  
Fei Chen ◽  
Xiaolong Hao ◽  
Fan Wang
Keyword(s):  
Heat Transfer ◽  
Power Generation ◽  
Energy Consumption ◽  
Air Temperature ◽  
Energy Supply ◽  
Energy Demand ◽  
Thermal Environment ◽  
Clean Energy ◽  
Solar Panel ◽  
Cooling Effect

<p>With the rapid development of social economy, China's energy demand has been growing at an alarming rate. The annual cumulative power generation is about  6.8 trillion kilowatts hour in 2017, and 70% of them is provided by fossil fuel resources, so it is important to promote the use of renewable and clean energy, such as solar power generation technology. The advantages of using solar panel roof in urban areas include reduction of the need of land use in the crowed city and less dependence on fossil fuels. However, there is need to understand impacts of solar roof on local climate, on energy supply during heatwaves, and associated economic benefits in China. This study selected a heatwave event in Jiangsu province, China to simulate the impact of solar panel roof on local thermal environment and energy supply. During that time, the cooling energy consumption reached more than half of the total electricity consumption. A new heat transfer scheme of solar panel roof was introduced into WRF/BEP/BEM model, which include layers (glass protective panel, solar panel, bottom plate) and was divided into two types for heat transfer calculation: bracket and non-bracket. The results showed that the urban average 2-m daytime temperature decreased by 0.3℃ in non-bracket case which is better than that of bracket case, while its cooling effect on nighttime temperature was small. For the bracket case, its cooling effect on daytime and nighttime air temperature were equal (0.2<sup>o</sup>C). Both solar panel roofs can reduce indoor daytime air temperature with the maximum cooling effect around 11:00 local time for non-bracket roof and 14:00 for bracket roof. However, bracket roof increased nighttime indoor air temperature and air-conditioning energy consumption. Solar panel roofs also reduce daytime turbulent kinetic energy and constrain the development of boundary layer. Results also show that with solar photoelectric conversion efficiency being 0.14, the photovoltaic power generation can meet 84.1%, 61.3% and 35.9% of the cooling energy consumption for high-density, low-density residential areas and commercial areas, respectively, during this heatwave event.</p>

Measurement of Thermal Environment for Ventilated Atrium in Guangzhou

2011 ◽  
Vol 71-78 ◽  
pp. 1898-1901
Author(s):  
Li Hua Zhao ◽  
Jun Lin Xie
Keyword(s):  
Energy Consumption ◽  
Solar Radiation ◽  
Air Temperature ◽  
Field Measurement ◽  
Thermal Environment ◽  
Cooling Effect ◽  
Sustainable Building

In the transition seasons, ventilated atrium play an important part in preventing solar radiation, strengthening ventilation, and reducing the energy consumption, so that it is widely used for developing sustainable building. The field measurement was carried out in this paper. This study had focus on comparing the air temperature in different height of the ventilated atrium, and analyzing the cooling effect of ventilation. Moreover, the paper pointed out that how the atrium to improve the thermal environment.

scholarly journals Energy-saving potential of intermittent heating system: Influence of composite phase change wall and optimization strategy

2020 ◽  
pp. 014459872096921
Author(s):  
Yanru Li ◽  
Enshen Long ◽  
Lili Zhang ◽  
Xiangyu Dong ◽  
Suo Wang
Keyword(s):  
Energy Consumption ◽  
Thermal Comfort ◽  
Phase Change ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Optimization Strategy ◽  
Indoor Thermal Environment ◽  
Indoor Thermal Comfort ◽  
Intermittent Heating

In the Yangtze River zone of China, the heating operation in buildings is mainly part-time and part-space, which could affect the indoor thermal comfort while making the thermal process of building envelope different. This paper proposed to integrate phase change material (PCM) to building walls to increase the indoor thermal comfort and attenuate the temperature fluctuations during intermittent heating. The aim of this study is to investigate the influence of this kind of composite phase change wall (composite-PCW) on the indoor thermal environment and energy consumption of intermittent heating, and further develop an optimization strategy of intermittent heating operation by using EnergyPlus simulation. Results show that the indoor air temperature of the building with the composite-PCW was 2–3°C higher than the building with the reference wall (normal foamed concrete wall) during the heating-off process. Moreover, the indoor air temperature was higher than 18°C and the mean radiation temperature was above 20°C in the first 1 h after stopping heating. Under the optimized operation condition of turning off the heating device 1 h in advance, the heat release process of the composite-PCW to the indoor environment could maintain the indoor thermal environment within the comfortable range effectively. The composite-PCW could decrease 4.74% of the yearly heating energy consumption compared with the reference wall. The optimization described can provide useful information and guidance for the energy saving of intermittently heated buildings.

scholarly journals Feasible Distributed Energy Supply Options for Household Energy Use in China from a Carbon Neutral Perspective

2021 ◽  
Vol 18 (24) ◽  
pp. 12992
Author(s):  
Yingxin Zhang ◽  
Sainan Wang ◽  
Wei Shao ◽  
Junhong Hao
Keyword(s):  
Power Generation ◽  
Energy Consumption ◽  
Human Development ◽  
Human Development Index ◽  
Energy Supply ◽  
Distributed Energy ◽  
Household Energy ◽  
Per Capita ◽  
Supply Systems ◽  
Energy Supply Systems

This contribution firstly proposed the concept of annual average power generation hours and analyzed per capita energy consumption, carbon emission, and the human development index from a macro perspective. On this basis, we compared the average household electrical energy consumption of urban and rural residents based on the data from CGSS-2015 from a micro perspective. The results show the positive correlation between carbon emissions per capita and the human development index and China’s regional imbalance characteristics between household electricity consumption and renewable energy distribution. Therefore, the distributed energy supply system is proposed as an effective complement to centralized power generation systems and is the key to synergizing human development and carbon emissions in China. Moreover, we analyzed the characteristics of distributed energy supply systems in the context of existing energy supply systems, pointing out the need to fully use solar energy and natural gas. Finally, two types of typical distributed energy supply systems are proposed for satisfying the household energy requirements in remote or rural areas of western and the eastern or coastal areas of China, respectively. Two typical distributed energy systems integrate high-efficiency energy conversion, storage, and transfer devices such as electric heat pumps, photovoltaic thermal, heat and electricity storage, and fuel cells.

scholarly journals Investment in Agrophotovoltaics: Efficient Solutions from Switzerland

2019 ◽  
Vol 8 (12) ◽  
pp. 61-64
Keyword(s):  
Power Generation ◽  
Power Systems ◽  
Energy Demand ◽  
Success Factors ◽  
Clean Energy ◽  
Efficient Solutions ◽  
Innovative Technology ◽  
Solar Panels ◽  
Energy Investment ◽  
Advantages And Disadvantages

The agrophotovoltaics innovative technology (APV) is a staged culture that combines photovoltaic power generation and agricultural production on the same land. The coexistence of solar panels and crops implies a sharing system of sunshine between these two types of production. It opens new horizons by making drylands cultivable while producing clean energy for local populations. APV lies at the heart of a global energy transformation, increasing world energy demand, negative global warming effects, and global water scarcity, and offers a promising investment to farmers and new opportunities for ecologically sustainable livelihoods. As a renewable energy investment, it meets the sustainability demand by reducing climate concerns but it also opens the door to significant socioeconomic benefits. However, the final outcome of the investment depends on government policies, environmental conditions, technical progress and what materials are used in solar power systems. This paper answers three questions: Why is the agrophotovoltaics an important technology today? What are the advantages and disadvantages of agrophotovoltaics use? And what are the economic risks related to this kind of investments? By analyzing Penthéréaz solar panels power generation example in Switzerland, the research illustrates the success factors to the investment and inherently provides recommendations regarding future investments.

scholarly journals Clean Energy Utilization Technology in the Transformation of Urban Existing Residence in China

2020 ◽  
Author(s):  
Li Zhao ◽  
Wei Chen ◽  
Qiong Li ◽  
WeiWei Wu
Keyword(s):  
Power Generation ◽  
Energy Consumption ◽  
Energy Saving ◽  
Residential Buildings ◽  
Clean Energy ◽  
Total Power ◽  
Residential Areas ◽  
Stirpat Model ◽  
Climatic Zones ◽  
Generation Capacity

Abstract Clean energy substitution technology of existing residential buildings in cities is an inevitable choice for sustainable development and low-carbon ecological city construction. In this paper, the current status of energy-saving renovation and renewable energy application of existing residential buildings in various cities in China is summarized by using statistical analysis method. According to different climatic zones of existing urban areas, the production and consumption of conventional energy (e.g. electricity, gas) and new energy (e.g. solar energy and air energy) are analyzed, and the energy consumption of buildings in existing urban residential areas is analyzed based on STIRPAT model principle. The influencing factors are modeled and analyzed quantitatively. The function relationship between energy consumption of existing residential buildings and influencing factors is analyzed by Ridge Regression with R software. The research results show that the areas with energy-saving modification area of existing buildings in China exceeding 10 million m2 by 2018 include: Xinjiang, Inner Mongolia and Shandong Province; based on data analysis of 2015-2017 in China with different climatic zones, the nuclear power generation capacity in hot summer and warm winter areas is ahead of other areas and the power generation capacity is increasing year by year; the wind power and solar power generation capacity in cold areas and cold areas is comparable. Strong and power generation also increases year by year; the proportion of clean energy generation in total power generation in each region is still small; the annual power generation of clean energy in each region is positively related to the total power generation. Based on STIRPAT model analysis, compared with 2009, urban residential energy consumption increased by 43.6% in 2016.Natural gas-based clean energy has also increased from 7.9% to 13.4%.But still cannot meet the demand of energy consumption of urban residential. The research results can provide basic data support for planning and implementation of clean energy upgrading and transformation system in existing urban residential areas in China.

Study on Development Path of Electric Vehicle in China from a View of Energy Conservation and Emission Reduction

2014 ◽  
Vol 525 ◽  
pp. 355-360
Author(s):  
Wei Zheng Kong ◽  
Bi Bin Huang ◽  
Qiong Hui Li ◽  
Xiao Lu Wang
Keyword(s):  
Power Generation ◽  
Energy Efficiency ◽  
Energy Consumption ◽  
Energy Conservation ◽  
Emission Reduction ◽  
Power Plants ◽  
Clean Energy ◽  
Pollutant Emissions ◽  
Total Power ◽  
Fossil Energy

In this paper, the change of fossil energy consumption, carbon dioxide (CO2) and pollutant emissions are calculated when petroleum based vehicles (PBVs) are taken place by EVs based upon the full-cycle energy efficiency theory with the energy efficiency measured from well to wheel.. Calculation results show that the fossil energy consumption, CO2, monoxide (CO) and hydrocarbon (HC) emissions can be reduced with the substitution of EVs for vehicles that burn gasoline (GVs), but nitrogen oxides (NOx) and sulfur dioxide (SO2) emissions increase. When vehicles that burn diesel (DVs) are replaced by EVs, the emissions of pollutants except SO2 will be reduced, but the emissions of CO2 and SO2 will increase. Considering the proportion of coal-fired power generation to the total power generation in China, the goal of energy conservation and emission reduction cannot be perfectly achieved by the substitution of PBVs by EVs. Therefore, the proportion of clean energy generation should be increased in China and technological updating of coal-fired power plants for reducing CO2 and pollutant emissions are necessary as well. Besides, GVs, other than DVs, should be replaced by EVs from the perspective of energy conservation and CO2 emission.

Study on Region Energy Allocation under Carbon Emission Constraints: Base on Analysis of Carbon Pinch

2014 ◽  
Vol 977 ◽  
pp. 149-154
Author(s):  
Hong Yu ◽  
Jun Feng Wang ◽  
Lei Hu
Keyword(s):  
Energy Supply ◽  
Energy Demand ◽  
Carbon Emission ◽  
Supply And Demand ◽  
Clean Energy ◽  
Energy Allocation ◽  
Energy Utilization ◽  
Practical Significance ◽  
Energy Structure ◽  
Regional Energy

Energy Supply and demand, and carbon emission constraints are the problems that must be considered in the process of rapid economic development by national and every province. Under the constraints of energy supply and demand, and carbon emissions, there has practical significance to rational allocate regional energy utilization. With carbon pinch method, this paper research the energy allocation of Tianjin, establish analysis model. Considering the overall and regional energy demand and carbon emission constraints, to determine the usage amount of every kind of fossil energy and clean energy, in order to achieve the best energy structure and optimal balance between energy supply and demand. To provide scientific evidence for local government to make reasonable energy supply and carbon emission constraint index.

scholarly journals Further Development of the Regional Boundary Layer Model to Study the Impacts of Greenery on the Urban Thermal Environment

2015 ◽  
Vol 54 (1) ◽  
pp. 137-152 ◽  
Author(s):  
Jianbo Yang ◽  
Hongnian Liu ◽  
Jianning Sun ◽  
Yan Zhu ◽  
Xueyuan Wang ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Air Temperature ◽  
Thermal Environment ◽  
Tree Planting ◽  
Cooling Effect ◽  
Layer Model ◽  
Boundary Layer Model ◽  
Urban Greenery ◽  
Tree Coverage ◽  
Regional Boundary

AbstractA forest canopy model is developed and coupled into the Regional Boundary Layer Model (RBLM) to fully consider the vertical structure of tree morphology. Instead of a slab surface model formerly used to represent trees in RBLM, the new version allows refinement of the radiation budgets as well as sensible and latent heat fluxes and, hence, more precise simulation of the thermal impacts of tree plantings on urban meteorological behavior. By applying this new version of RBLM, sensitivity tests are conducted to explore the potential impacts of different greenery scenarios on the thermal environment in an eastern Chinese city, Suzhou, during hot summer days. Greenings, both tree planting and grass surfacing, are beneficial in cooling the ambient air temperature. In general, tree planting is more beneficial than grass surfacing with the same coverage. In terms of surface energy balance, with tree coverage increasing from 0% to 20%, and then to 40%, the average surface net radiation fluxes at noon (1200 LST) are 591, 512, and 421 W m−2, respectively. Correspondingly, the Bowen ratio is reduced from 8.78 to 1.20 and then to 0.43 as result of the redistribution of solar energy absorbed at the ground. The cooling effect of trees is more significant at noontime and can remarkably lower the daily maximum air temperature in urban areas. The cooling effect of urban greenery increases with its coverage. Using the study results, a tree coverage of around 40% may be a feasible and optimized urban greenery scheme.

scholarly journals Biogas Technology in Germany and Romania: Comparative Aspects and Achievements

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Mihaela PALELA ◽  
Carmen SOCACIU
Keyword(s):  
Energy Consumption ◽  
Energy Demand ◽  
Biogas Production ◽  
Clean Energy ◽  
European Countries ◽  
Social Strategies ◽  
Renewable Materials ◽  
Final Energy ◽  
Energy Technologies ◽  
Final Energy Consumption

The European Union’s policies regarding the energy security impose to the European countries to take urgent measures because of the global energy demand which is growing rapidly. The ambitious target approved by the renewable energy directive is that 20 % of the final energy consumption has to be provided by renewable sources by 2020. The technological transfer from west to east Europe encourages the eastern countries with a high agricultural potential to develop political, economical, and social strategies to replace the fossil resources with the renewable materials. The main goal of the European countries is to promote the clean energy technologies. Thus, the share of renewable resources such as wind, solar, biomass, geothermal, biogas, etc. has to be increases with 24 % of the final energy consumption compared to the overall EU target of 20 %. The current work emphasize the technological state and perspectives of the biogas production of the Romanian country in comparison with the leader country in Europe, Germany.

scholarly journals Effects of PCM thermal properties and thermodiode panel (TDP) on buildings' energy demand and indoor temperature

2021 ◽  
Author(s):  
Mohammad Ebrahim Poulad
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Thermal Properties ◽  
Air Temperature ◽  
Indoor Air ◽  
Energy Demand ◽  
Temperature Fluctuations ◽  
Solar Thermal Energy ◽  
Indoor Temperature ◽  
Aluminium Sheets

The performance of a thermodiode panel (TDP) is investigated thoroughly. A phase change material (PCM) layer is integrated into the TDP. A TDP can transfer solar thermal energy into the building. Adding a PCM layer to the TDP adds capacity of storing solar energy into the TDP, and releases the stored energy when the sun goes down. The TDP is composed of dense foam, which is sandwiched between two aluminium sheets, and a thermosyphon passes through the foam layer. PCM layer is added to the condenser section of the TDP that is connected into the building envelope. PCM thermal properties and their effects on energy demand and indoor temperature are investigated on a typical building. The best melting point for the PCM was found to be a temperature in the middle of the set points (upper and lower). Quantitative indices are introduced to evaluate the effects of PCM on indoor air temperature fluctuations. PCM reduces the indoor air temperature fluctuations. Increasing thermal conductivity of PCM by an order of magnitude reduces about 2% annual energy demand of a building. Regarding convention heat transfer coefficient, by increasing the convective heat transfer coefficient at interior wall surface, the cooling demand slightly increases in summer. In winter, energy demand is sensitive to h-value with a positive correlation. Matlab codes developed using genetic algorithm to optimize the TDP sizes, i.e., thicknesses of three aluminium sheets, copper tube diameter and its thickness that makes the structure of thermosyphon. The optimum sizes found to be: plate thicknesses of 1.5 mm, 2.5 mm, and 2 mm and thermosyphon diameter and thickness of 32 mm and 9 mm, respectively, provide the maximum objective function (the best performance of the TDP). Thermal bridging of a TDP can be reduced 76 times by adding a piece of Teflon in the thermosyphon assembly. The integration can do both store and collect/gain solar thermal energy, which makes this panel a novel alternative for south walls. It is also shown that thermosyphon angle from the horizon shall be between 30 and 45 degree to have the best performance of the TDP.

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