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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - Quantum cascade laser-based in situ measurement of atmospheric CO and CO <sub/>2</sub> in Gandhinagar using 1f and 2f wavelength modulation spectroscopy
摘要： We report the design, development and field deployment of a quantum cascade laser-based tunable diode laser spectroscopy (TDLS) system for high-sensitivity measurement of atmospheric CO and CO2. Two distributed-feedback quantum cascade lasers are used to interrogate the rotational-vibrational transitions of CO at 4594.99 nm and CO2 at 4319.30 nm. The mean mole fraction values for CO and CO2 for the measurements made at Gandhinagar from 19-25 July 2019 are 477 ppb and 486 ppm respectively. The detection limit of the system is 3 ppb CO and 45 ppb CO2 for integration time of 17 s and 69 s respectively.
关键词： air quality monitoring,greenhouse gas monitoring,quantum cascade laser,wavelength modulation spectroscopy
更新于2025-09-23 15:19:57
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Thermo-environomic assessment of an integrated greenhouse with an adjustable solar photovoltaic blind system
摘要： Optimum energy consumption and renewable energy utilization reduce environmental impacts and are cost-effective. They are the key aspects of achieving sustainable energy management, such as in the agricultural industry. The contribution of the horticultural section in the global energy demand is approximately 2%, and among its various sections, greenhouses are one of the main systems in modern agriculture that have a great share on energy consumption. In this study, a rose greenhouse is examined and modeled in EnergyPlus as a greenhouse reference (GR). Validation of the developed greenhouse model is carried out with a site experimental measurement. Using the GR as the basic model, 14 various configurations of greenhouses have been assessed by considering a solar photovoltaic blind system (SPBS) in checkerboard arrays 1 meter above the greenhouse roof. These modified greenhouses called solar-blind greenhouses (SBGs) have different shading rates and SPBS sizes. To perform a Thermo-environomic assessment, the effects of various parameters, including temperature, relative humidity, natural gas consumption, electricity consumption, and carbon dioxide (CO2) emission reduction, are studied. Results indicate that covering 19.2% of the roof, with no significant change in the illumination level on the plant canopy, will annually reduce natural gas consumption, electricity demand, and CO2 emission by 3.57%, 45.5%, and 30.56 kg/m2, respectively. Moreover, with the SPBS, the annual electricity production is approximated at 42.7 kWh/m2.
关键词： Energy,Solar Greenhouse,Photovoltaic,Thermo-environomic,Solar Blind System
更新于2025-09-23 15:19:57
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Performance analysis of photovoltaic-thermal air collectors combined with a water to air heat exchanger for renewed air conditioning in building
摘要： In this work, a new solar system that includes photovoltaic-thermal (PVT) air collectors coupled to a water-to-air heat exchanger is investigated. The considered system generates sufficient energy for cooling and heating of the ambient air injected in a 300 m2 tertiary building and saves its total energy consumption. Therefore, it allows the minimization of greenhouse gas emissions of the building. A numerical model is developed to ensure comfortable temperatures during summer and winter, including days with the highest energy needs. The results show that the proposed system can generate the required heating and cooling needs using an airflow rate equal to 0.25 kg/s and a PVT area of 17 m2. It was found that the coupling of the PVT air collectors with a water to air heat exchanger minimizes the total required area for heating by ~ 33%. Moreover, the PV module’s efficiency was enhanced by 2.0% in winter and 5.1% in summer. The thermal energy saved for heating, thermal energy saved for cooling and the electrical energy saved are, respectively, equal to 15.30 kWh/day, 24.79 kWh/day, and 3.14 kWh/day. This represents an average emission reduction of 11.4 kg CO2 per day.
关键词： Water to air heat exchanger,Energy saving,Thermal comfort in buildings,Photovoltaic air collectors,Renewable energies,Greenhouse gas emissions
更新于2025-09-23 15:19:57
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Greenhouse gas emission reduction by the selection of efficient lighting systems
摘要： Indoor lighting is one of the most important consumer of the energy worldwide, driving to a high GHG emissions. Current state of the lighting system in the classrooms of the Technical University of Ambato (UTA), Tungurahua, Ecuador has been assessed in this work. A sample of classrooms were selected to quantify its illumination levels, with the Luxometer (Sper Scientific 850007), these data were computed by means of DIALUX software, whose generates the light distribution of different lighting systems scenarios and the lamps geometric distribution. Number of luminaires, luminous distribution and the energy efficiency value of the installation (VEEI) were compared among all the different cases, also a luminance analysis and the energy efficiency of installation was performed. First results show an important reduction of around 40% of the energy at present consumed, decreasing the emission of almost 200 tons of CO2 equivalent per year.
关键词： DIALUX software,energy efficiency,Greenhouse gas emission,LED technology,efficient lighting systems
更新于2025-09-23 15:19:57
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The effect of dynamic solar heat load on the greenhouse microclimate using CFD simulation
摘要： Indoor greenhouse temperature exceeds tolerable range for plants growth mostly during the summer in Ahvaz-Iran. Attempts for improving ventilation in summer was not adequate despite a huge energy consumption. Computational fluid dynamic models of a full scaled gable greenhouse covered by semitransparent materials among several adjacent greenhouses inside a greenhouse paradise for predicting the dynamics of its microclimate during a day as well as a year 2017-2018 were developed. The accuracy of the models was approved by comparing to the physical experiments and meteorological reports. The results approved the capability of the model for predicting variable solar heat load and higher indoor temperature than ambient in several hours of a day as well as surface heat transfer coefficient of the walls as affected by regional dominant wind profile. This study enhanced the understanding of required solar heat load removal during the hot months while the average temperature exceeds 40 °C for more than 11 hours a day. This finding also indicates the critical periods in which the fan assisted natural ventilation system can be applied to cool down the greenhouse from more than 40 °C to 25 to 35 °C.
关键词： Greenhouse,Temperature distribution,Modeling,Solar radiation,Dynamic microclimate,CFD
更新于2025-09-19 17:15:36
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Analysis of the Day-ahead Deviation Plan and Research on the Real-time Scheduling of Photovoltaic Greenhouses Based on Exergy Theory
摘要： For the correction problem of day-ahead plan deviation caused by energy prediction deviation in day-ahead scheduling stage of photovoltaic greenhouses, an exergy analysis method is used to propose the deviation model of heat required for photovoltaic greenhouses. Based on the deviation model, a real-time optimization scheduling model is established. The deviation model not only considers the non-negligible exergy loss during heating process of pipes, but also considers the di?erence between heat and thermal exergy a?ected by the actual indoor temperature. The goal of the real-time scheduling model is to minimize the absolute value of the di?erence between the energy supply and demand prediction deviation to be corrected and the adjustment of multi-form energy storage and electric loads, so that develop the real-time adjustment plan of energy storage and electric loads. The analysis results of the actual photovoltaic greenhouse show that of the heat required by a greenhouse based on the exergy theory calculation, the exergy loss of the heating process accounts for about 10%–20% of the total thermal exergy required and it cannot be ignored, so the calculation results can re?ect the actual heat required more accurately and the greenhouse temperature is more suitable for plant growth. Moreover, the proposed real-time scheduling model can correct the deviation of the day-ahead plan and improve local consumption. The promotion ratio can reach 7%. Finally, the farmers’ electricity purchases cost is reduced. Thereby the e?ectiveness of the proposed heat deviation model and real-time scheduling model is veri?ed.
关键词： photovoltaic greenhouse,real-time scheduling,exergy,deviation of the day-ahead plan
更新于2025-09-19 17:13:59
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Organic Photovoltaics on Greenhouse Rooftops: Effects on Plant Growth
摘要： Greenhouse agriculture is a high-growth and high-volume market that rapidly expands worldwide to address the societal needs for food production. The increasing demand for energy to cover their requirements, coupled with the limited amount of available fossil fuels, has turned the agriculture community in the exploitation of renewable energy sources. Intensive research is currently focuses on the use of solar energy in agriculture constructions. Organic Photovoltaics (OPVs) are constantly gaining ground among other PV technologies due to their low weight, tunable optical transmittance, flexibility and high conformability. In this work, semi-transparent OPVs based on the blend of regioregular poly(3-hexylthiophene) (P3HT) and phenyl-C61-butyric acid methyl ester (PCBM) were integrated on the rooftop of the 24 m2 experimental Mediterranean greenhouse covering the 22% of its total area in order to investigate its effect on the growth and behavior of cultivated pepper plants (Capsicum annuum). Under the shade of OPVs, the pepper plants produced 20.2% more fruit mass compared to the control ones. In addition, at the end of the growing season, the height of the shaded plants was 21.8% larger than the remaining plants.
关键词： shading effect,solar energy,greenhouse,semi-transparent OPVs,printed photovoltaics
更新于2025-09-12 10:27:22
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Alternating Red and Blue Light-Emitting Diodes Allows for Injury-Free Tomato Production With Continuous Lighting
摘要： Plant biomass is largely dictated by the total amount of light intercepted by the plant [daily light integral (DLI) — intensity × photoperiod]. Continuous light (CL, 24 h lighting) has been hypothesized to increase plant biomass and yield if CL does not cause any injury. However, lighting longer than 18 h causes leaf injury in tomato characterized by interveinal chlorosis and yield is no longer increased with further photoperiod extension in tomatoes. Our previous research indicated the response of cucumbers to long photoperiod of lighting varies with light spectrum. Therefore, we set out to examine greenhouse tomato production under supplemental CL using an alternating red (200 μmol m?2 s?1, 06:00–18:00) and blue (50 μmol m?2 s?1, 18:00–06:00) spectrum in comparison to a 12 h supplemental lighting treatment with a red/blue mixture (200 μmol m?2 s?1 red + 50 μmol m?2 s?1 blue, 06:00–18:00) at the same DLI. Our results indicate that tomato plants grown under supplemental CL using the red and blue alternating spectrum were injury-free. Furthermore, parameters related to photosynthetic performance (i.e., Pnmax, quantum yield, and Fv/Fm) were similar between CL and 12 h lighting treatments indicating no detrimental effect of growth under CL. Leaves under CL produced higher net carbon exchange rates (NCER) during the subjective night period (18:00–06:00) compared to plants grown under 12 h lighting. Notably, 53 days into the treatment, leaves grown under CL produced positive NCER values (photosynthesis) during the subjective night period, a period typically associated with respiration. At 53 days into the growth cycle, it is estimated that leaves under CL will accumulate approximately 800 mg C m?2 more than leaves under 12 h lighting over a 24 h period. Leaves grown under CL also displayed similar diurnal patterns in carbohydrates (glucose, fructose, sucrose, and starch) as leaves under 12 h lighting indicating no adverse effects on carbohydrate metabolism under CL. Taken together, this study provides evidence that red and blue spectral alternations during CL allow for injury-free tomato production. We suggest that an alternating spectrum during CL may alleviate the injury typically associated with CL production in tomato.
关键词： photoperiod,light-emitting diodes,continuous lighting,tomato,spectral quality,greenhouse,net carbon exchange rate,supplemental lighting
更新于2025-09-12 10:27:22
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Quantifying Isotopic Signatures of N <sub/>2</sub> O Using Quantum Cascade Laser Absorption Spectroscopy
摘要： Nitrous oxide, N2O, is the environmentally most relevant constituent of the biogeochemical nitrogen cycle. Human activities, e.g. the agricultural use of mineral fertilizers, accelerate nitrogen transformations, leading to higher emissions of this strong greenhouse gas. Investigating the stable isotopic composition of N2O provides a better understanding of formation mechanisms to disentangle its variable source and sink processes. Mid-infrared (mid-IR) laser spectroscopy is a highly attractive technique to analyze N2O isotopocules based on their specific ro-vibrational absorption characteristics. Specifically, quantum cascade laser absorption spectroscopy (QCLAS) in combination with preconcentration has shown to be powerful for simultaneous and high-precision analysis of the main N2O isotopocules. Recently, in the scope of my PhD project, we have been advancing this analytical technique for the analysis of the very rare doubly substituted N2O isotopic species 15N14N18O, 14N15N18O, and 15N15N16O, also known as clumped isotopes. Currently, we are investigating the potential of these novel isotopic tracers to track the complex N2O production and consumption pathways. Improved understanding of the nitrogen cycle will be a major step towards N2O emission reduction.
关键词： Laser spectroscopy,Nitrous oxide,Greenhouse gas,Biogeochemical nitrogen cycle,Clumped isotopes
更新于2025-09-12 10:27:22
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Profiling wind and greenhouse gases by infrared-laser occultation: results from end-to-end simulations in windy air
摘要： The new mission concept of microwave and infrared-laser occultation between low-Earth-orbit satellites (LMIO) is designed to provide accurate and long-term stable profiles of atmospheric thermodynamic variables, greenhouse gases (GHGs), and line-of-sight (l.o.s.) wind speed with focus on the upper troposphere and lower stratosphere (UTLS). While the unique quality of GHG retrievals enabled by LMIO over the UTLS has been recently demonstrated based on end-to-end simulations, the promise of l.o.s. wind retrieval, and of joint GHG and wind retrieval, has not yet been analyzed in any realistic simulation setting. Here we use a newly developed l.o.s. wind retrieval algorithm, which we embedded in an end-to-end simulation framework that also includes the retrieval of thermodynamic variables and GHGs, and analyze the performance of both stand-alone wind retrieval and joint wind and GHG retrieval. The wind algorithm utilizes LMIO laser signals placed on the inflection points at the wings of the highly symmetric C18OO absorption line near 4767 cm?1 and exploits transmission differences from a wind-induced Doppler shift. Based on realistic example cases for a diversity of atmospheric conditions, ranging from tropical to high-latitude winter, we find that the retrieved l.o.s. wind profiles are of high quality over the lower stratosphere under all conditions, i.e., unbiased and accurate to within about 2 m s?1 over about 15 to 35 km. The wind accuracy degrades into the upper troposphere due to the decreasing signal-to-noise ratio of the wind-induced differential transmission signals. The GHG retrieval in windy air is not vulnerable to wind speed uncertainties up to about 10 m s?1 but is found to benefit in the case of higher speeds from the integrated wind retrieval that enables correction of wind-induced Doppler shift of GHG signals. Overall both the l.o.s. wind and GHG retrieval results are strongly encouraging towards further development and implementation of a LMIO mission.
关键词： greenhouse gases,Doppler shift,microwave and infrared-laser occultation,line-of-sight wind speed,upper troposphere and lower stratosphere
更新于2025-09-12 10:27:22