- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Energy/exergy based-evaluation of heating/cooling potential of PV/T and earth-air heat exchanger integration into a solar greenhouse
摘要： Through the present paper, a solar greenhouse integrated with an Earth-Air Heat Exchanger (EAHE) and Photovoltaic/Thermal collectors (PV/Ts) was theoretically studied in terms of energy and exergy and validated against an experimental study presented in literature i.e. a solar greenhouse with floor area, buried pipe length and PV area of 24m2, 39m and 9.68m2, respectively. The comparisons showed a fairly good agreement between the theoretical and experimental results with a relatively high coefficient of correlation around 95%. Afterwards, the given solar greenhouse was optimized in terms of energy and exergy efficiencies while the results indicated that only length of EAHE pipes showed an optimum value equal to 38m on average. Moreover, the results showed that PV/Ts did not have a significant heating potential for raising the greenhouse air and plant temperatures and only the electricity generation potential of PVs was favorable. However, the EAHE integration seemed promising in raising and lowering the temperatures of greenhouse air by 9°C and 8°C in summer and winter, respectively. Moreover, the Temperature Load Leveling (TLL) due to integration of only EAHE was achieved 46% and 58% in summer and winter, respectively.
关键词： Greenhouse,Heating potential,PV/T,Earth-air heat exchanger
更新于2025-09-23 15:23:52
-
[IEEE 2018 International Conference on Applied Engineering (ICAE) - Batam, Indonesia (2018.10.3-2018.10.4)] 2018 International Conference on Applied Engineering (ICAE) - An Integrated Comparative Approach to Estimating Forest Aboveground Carbon Stock Using Advanced Remote Sensing Technologies
摘要： Greenhouse gases in the atmosphere play a very important role in maintaining the temperature of the earth. Plants absorb carbon in the atmosphere in the form of CO2 which is beneficial for photosynthesis which will produce O2 into the atmosphere. By utilizing remote sensing technology and field data integration, this research aims to estimating aboveground carbon reserves in the research area. The results of this research indicate that the above ground carbon stock resulting from estimation calculations using remote sensing data and field calculations using brown allometric are 103,397 TonC / Ha with an error rate of 1,8354. This error level indicates the size of the error in the estimated value of each pixel.
关键词： Carbon Stock,Batam Island,Temperature,Remote Sensing Data,Greenhouse Gases
更新于2025-09-23 15:22:29
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Carbon Dioxide and Water Vapour Fluxes of a Alkaline Fen and Their Dependence on Reflectance
摘要： This study shows results of parallel measurements of greenhouse gases fluxes (carbon dioxide and water vapour) and canopy reflectance of alkaline fen. Fluxes were measured using eddy-covariance technique on micrometeorological station located in the Upper Biebrza Basin (NE Poland) in Rogo?ynek Village. Study site is located in the Biebrza National Park which was established to protect one of the biggest coherent lowland wetland area in the Central Europe. Statistical relations of reflectance and spectral indices with fluxes were calculated based on measurements during two growing season (2015 and 2016). Four types of functions were examined: linear, quadratic, exponential and logarithmic and for two timestamps: half-hour and day. The correlation between carbon dioxide fluxes and reflectance is better than for water vapour fluxes. For both carbon dioxide and water vapour we obtained higher correlations coefficients using selected spectral indices than using reflectance and higher correlations for daily timestamp than for half-hour fluxes.
关键词： greenhouse gases,eddy-covariance technique,spectral indices,Biebrza River valley,wetland
更新于2025-09-23 15:22:29
-
Photothermal/day lighting performance analysis of a multifunctional solid compound parabolic concentrator for an active solar greenhouse roof
摘要： Currently, the excess light above a light saturation point cannot be harnessed for plant growth in conventional greenhouse covers. In this study, we developed a solid compound parabolic concentrator (CPC) cover for use in greenhouses to convert excess light into heat. Optical simulation software was used to track the sunlight at different incident angles over time. We also conducted experiments to determine the transmittance and heating power of the solid CPC coating under real weather conditions. The maximum instantaneous thermal efficiency and thermal energy of a single solid CPC cover plate were 32.2% and 353 W/m2, respectively. The simulation results were in good agreement with the experimental output power and the trend of the actual transmittance of the covering material. The transmittance of the covering material was low when the midday sun was intense, and the transmittance was relatively high in the morning and afternoon. The variation of red and blue light in the greenhouse with the spectrum was analyzed at the same time. Studies have shown that this new greenhouse covering material can better adjust the brightness, make the illumination in the greenhouse more uniform, and thus improve the thermal environment in the greenhouse. The heat pipes converted excess light into heat, thereby achieving comprehensive utilization of solar light and heat.
关键词： Heat energy utilization,Solid CPC,Solar greenhouse roof,Light transmittance,Solar PT/D system
更新于2025-09-23 15:22:29
-
Preliminary application of diffuse light film in a Chinese solar greenhouse
摘要： To explore the application of diffuse light film in a Chinese solar greenhouse (CSG), we did several comparative trials in CSGs in Beijing, Ningxia and Shandong provinces. We did three contrast tests on CSG cover films with average haze of 16.8 and 36.2%, including trials on tomatoes (in Beijing, seedlings; in Shandong, cultivation) and cucumbers (in Beijing, seedlings); the other four experiments used with films in an average haze 24.2 and 39.7%, which included trials on tomatoes (in Beijing, seedlings; in Ningxia, cultivation) and cucumbers (in Beijing, seedlings; in Ningxia, cultivation). Plant growth parameters, yield and quality index were evaluated. The result of preliminary tests showed that a higher haze film was able to improve homogeneity of light in the crop canopy and had a positive effect on cultivation. For example, in the contrast tests, we observed that a film with higher haze contributed to increases in plant height, stem diameter, leaf area, SPAD chlorophyll index, and seedling index; the seedling indices of tomatoes and cucumbers were enhanced by 50 and 10.5%, respectively, and their yields were increased by 17.0 and 21.9%, respectively, which demonstrated the outstanding impact of the higher haze films on production. Furthermore, it played a significant and positive role in flower bud differentiation of cucumbers, harvest time of tomatoes and cucumbers, and fruit quality of both crops. Based on the results of these preliminary tests, it can be concluded the diffuse film was able to accelerate plant growth and enhance crop production.
关键词： diffuse light film,Chinese solar greenhouse,tomato,cucumber
更新于2025-09-23 15:22:29
-
Near-infrared remote sensing of Los Angeles trace gas distributions from a mountaintop site
摘要： The Los Angeles basin is a significant anthropogenic source of major greenhouse gases (CO2 and CH4) and the pollutant CO, contributing significantly to regional and global climate change. We present a novel approach for monitoring the spatial and temporal distributions of greenhouse gases in the Los Angeles basin using a high-resolution spectroscopic remote sensing technique. A new Fourier transform spectrometer called CLARS-FTS has been deployed since May, 2010, at Jet Propulsion Laboratory (JPL)'s California Laboratory for Atmospheric Remote Sensing (CLARS) on Mt. Wilson, California, for automated long-term measurements of greenhouse gases. The instrument design and performance of CLARS-FTS are presented. From its mountaintop location at an altitude of 1673 m, the instrument points at a programmed sequence of ground target locations in the Los Angeles basin, recording spectra of reflected near-IR solar radiation. Column-averaged dry-air mole fractions of greenhouse gases (XGHG) including XCO2, XCH4, and XCO are retrieved several times per day for each target. Spectra from a local Spectralon? scattering plate are also recorded to determine background (free tropospheric) column abundances above the site. Comparisons between measurements from LA basin targets and the Spectralon? plate provide estimates of the boundary layer partial column abundances of the measured species. Algorithms are described for transforming the measured interferograms into spectra, and for deriving column abundances from the spectra along with estimates of the measurement precision and accuracy. The CLARS GHG measurements provide a means to infer relative, and possibly absolute, GHG emissions.
关键词： column abundances,remote sensing,greenhouse gases,Fourier transform spectrometer,Los Angeles basin
更新于2025-09-23 15:22:29
-
GreenLight a?? An open source model for greenhouses with supplemental lighting: Evaluation of heat requirements under LED and HPS lamps
摘要： Greenhouse models are important tools for the analysis and design of greenhouse systems and for offering decision support to growers. While many models are available, relatively few include the influence of supplementary lighting on the greenhouse climate and crop. This study presents GreenLight, a model for greenhouses with supplemental lighting. GreenLight extends state of the art models by describing the qualitative difference between the common lighting system of high-pressure sodium (HPS) lamps, and the newest technology for horticultural lighting - the light-emitting diodes (LEDs). LEDs differ from HPS lamps in that they operate at lower temperatures, emit mostly convective heat and relatively little radiative heat, and can be more efficient in converting electricity to photosynthetically active radiation (PAR). These differences can have major implications on the greenhouse climate and operation, and on the amount of heat that must be supplied from the greenhouse heating system. Model predictions have been evaluated against data collected in greenhouse compartments equipped with HPS and LED lamps. The model predicted the greenhouse's heating needs with an error of 8e51 W m-2, representing 1e12% of the measured values; the RMSE for indoor temperature was 1.74e2.04 °C; and the RMSE for relative humidity was 5.52e8.5%. The model is freely available as open source MATLAB software at https://github.com/davkat1/GreenLight. It is hoped that it may be further evaluated and used by researchers worldwide to analyse the influence of the most recent lighting technologies on greenhouse climate control.
关键词： Energy use,Greenhouse lighting,LEDs,Greenhouse models,Crop models,Open source
更新于2025-09-23 15:21:01
-
Thiazolo[5,4- <i>d</i> ]thiazole-based organic sensitizers with improved spectral properties for application in greenhouse-integrated dye-sensitized solar cells
摘要： Organic photosensitizers especially designed for producing semitransparent dye-sensitized solar cells (DSSCs) for greenhouse integration were prepared by introduction of different heterocyclic moieties into the thiazolo[5,4-d]thiazole-molecular scaffold. The aim was that of improving their light absorption capability in the green part of the visible spectrum while maintaining a good transparency in the blue and red regions, where the photosynthetic response is maximized. A short and efficient synthetic approach, featuring two consecutive C-H activation reactions in a one-pot procedure as key steps, was used. Based on their spectroscopic and electrochemical characterization, two of dyes prepared appeared especially suitable for greenhouse-integrated photovoltaics. The corresponding semitransparent DSSCs yielded 5.6-6.1% power conversion efficiencies, which were largely superior to those provided by other organic dyes previously proposed for the same application.
关键词： organic photosensitizers,light absorption,photovoltaic efficiency,dye-sensitized solar cells,greenhouse integration,thiazolo[5,4-d]thiazole,transparency
更新于2025-09-23 15:21:01
-
Bumblebees land remarkably well in red-blue greenhouse LED light conditions
摘要： Red-blue emitting LEDs have recently been introduced in greenhouses to optimize plant growth. However, this spectrum may negatively affect the performance of bumblebees used for pollination, because the visual system of bumblebees is more sensitive to green light than to red-blue light. We used high-speed stereoscopic videography to 3D track and compare landing manoeuvres of Bombus terrestris bumblebees in red-blue light and in regular, broad-spectrum white light. In both conditions, the landing approaches were interspersed by one or several hover phases, finally followed by leg extension and touchdown. The time between leg extension and touchdown was 25% (0.05 s) longer in red-blue light than in white light, caused by a more tortuous flight path in red-blue light. However, the total landing duration, specified as the time between the first hover phase and touchdown, did not differ between the light conditions. This suggests that the negative effects of red-blue light on the landing manoeuvre are confined to the final phase of the landing.
关键词： landing,red-blue LED light,pollination,bumblebees,greenhouse
更新于2025-09-23 15:21:01
-
Optically controlled millimetre-wave switch with stepped-impedance lines
摘要： Nitrogen (N) placement can impact nitrogen use efficiency, but its effect on greenhouse gas (GHG) emissions remain unclear. The objective of this study is to compare the effects of four different N horizontal placement methods (i.e., annular canal (An), radial canal (Ra), band (Ba), and nest fertilization (Ne)) with urea broadcast (Br) on nitrous oxide (N2O), methane (CH4), and soil heterotrophic respiration carbon dioxide (CO2) emissions from an apple orchard to assess the seasonal and spatial variations in these gas emissions. The total cumulative GHG emissions are determined through spots that are differentiated as fertilized or unfertilized. A field simulation study is conducted in an apple orchard, and all N sources have an application rate of 300 kg N ha?1. from the Br treatment are significantly lower than those of other treatments, and the emissions from the Ne treatment are 1.7-fold higher than those of the Br treatment. Surprisingly, the cumulative N2O emissions from the Br treatment are significantly higher than those of the other four treatments. N horizontal placement does not significantly influence the soil CH4 sink. The CO2 emissions in the Br treatment are higher than in other treatments. High N2O emissions in the Br treatment result in a significantly higher GHG exchange than in other treatments, while the Ne treatment significantly reduces the GHG exchange throughout the measurement period. Therefore, optimizing N placement may serve as an effective way to reduce GHG emissions from arable soils.
关键词： nitrogen placement,nitrous oxide,nest fertilization,greenhouse gas emissions,nitrogen use efficiency
更新于2025-09-23 15:19:57