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- 实验方案
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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
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[IEEE 2018 International Conference on Information and Communication Technology Robotics (ICT-ROBOT) - Busan (2018.9.6-2018.9.8)] 2018 International Conference on Information and Communication Technology Robotics (ICT-ROBOT) - Design of Air Cooling Housing for Image Sensors Using Additive Manufacturing Technology
摘要： Machine vision is widely used in industry for monitoring and inspection. In additive manufacturing technology (AM), it is especially important in that it can cover an entire 2-dimensional printed surface area instantly. Additionally, AM technologies can also be used to make a mechanical part for a machine vision system such as mount or illumination devices on a 3D printer. For the industrial 3D printer, the camera mount requires to have temperature control capabilities for the vision system. This research aims to develop a method to build a mount with cooling capability with AM technology. This paper introduces a 3D printed camera cooling housing and proposes a temperature feed-back control method based on the image sensor itself without adding a thermal sensor to increase the user friendliness and simplicity. In the demonstration, a camera cooling housing that was developed enabled a camera module to operate at 200°C in an industrial Fortus 400 (Stratasys, MN).
关键词： camera cooling system,3d printed heat exchanger,additive manufacturing,vision based thermal control
更新于2025-09-23 15:22:29
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Analysis of a multistage solar thermal energy accumulator
摘要： The present work evaluates the effect of using two paraffin wax with different solidification points as PCM, stored in soda cans and sequentially distributed, on the discharge efficiency of solar thermal energy accumulators in laboratory and prototype scales. The discharge efficiency ranges found were [74 %, 92 %] and [49 %, 61 %] for the laboratory and prototype scale models respectively. Greater efficiency values were obtained in both accumulators when the first rows of soda cans exposed to the incoming air was filled with the PCM of lower solidification point (41 °C) and the last row with PCM of higher solidification point (56 °C). Numerical solution of the mathematical modeling allowed to predict the outlet air temperature which compared with experimental data. Bigger discrepancies with the simulation results were obtained in the prototype scale accumulator due to the variability of the environmental conditions. As conclusion we stated that it is possible to enhance the discharge efficiency of a solar energy accumulator by using two PCM with different solidification points. The implemented mathematical model allowed to predict the time evolution of the air temperature at the accumulators outlet. Row order and paraffin wax type allow to adjust the energy discharge rate depending on the application type.
关键词： Paraffin wax,Solar energy,Heat exchanger,Thermal conductivity
更新于2025-09-23 15:22:29
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Improving the performance and economic analysis of photovoltaic panel using copper tubular-rectangular ducted heat exchanger
摘要： This research empirically and theoretically assessed the performance of a solar photovoltaic (PV) panel in five different cooling configurations under the weather conditions of Sanandaj, Iran in September 2018. The findings indicated that, compared to the simple PV mode, the increased mean electrical efficiencies over the whole experiment were 0.27%, 0.5%, 0.72%, 0.6, and 0.88% for the PV/w-XP, PV/w-XD, PV/w-2XDP, PV/a ,and PV/b-2XDP modes, respectively. Further, the highest electrical power for the PV/w-XP, PV/w-XD, PV/w-2XDP, PV/a, and PV/b-2XDP modes increased by 6.8, 12.17, 16.83, 13.17, and 18.92%, respectively compared to the simple PV mode. The monthly electrical output energy the PV/S, PV/w-XP, PV/w-XD, PV/w-2XDP, PV/a, and PV/b-2XDP modes were 28.24 kWh/A, 29.16 kWh/A, 30.34 kWh/A, 31.81 kWh/A, 31.15 kWh/A, and 32.9 kWh/A, respectively. Then, an economic analysis was carried out for the system with two adjustment coefficients. The results showed that although the payback period with an interest rate and an adjustment coefficient of 10% was 2.72 years longer in the PV/b-2XDP than in the PV/S, the annual worth over 20 years was State USD 3.32 (SANA USD 1.07) higher in the PV/b-2XDP mode than in the PV/S mode by considering merely the electrical section. Hence, considering the outlet hot water and air, PV/b-2XDP is more economical to use.
关键词： Water tubular and channel heat exchanger,Photovoltaic panel,Payback period,Thermoelectric
更新于2025-09-23 15:21:01
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Numerical and experimental investigation of the energy and exergy performance of solar thermal, photovoltaic and photovoltaic-thermal modules based on roll-bond heat exchangers
摘要： This paper presents numerical and experimental energy and exergy performance assessments of solar thermal (ST), photovoltaic (PV) and photovoltaic/thermal (PV/T) modules based on roll-bond heat exchangers having three different channel geometries: serial, parallel and bionic. The validation of a coupled numerical simulation encompassing the thermo-hydraulic and electrical properties shows that 78% of all the data lies within a ± 10% uncertainty. The thermo-hydraulic simulation shows that the lowest outlet-water temperature inside the absorber is for the case of the bionic absorber (average 44.1 °C vs. 46.5 °C for the serial). This geometry is also beneficial when considering pressure losses, since compared to the parallel configuration (average 778 Pa) the bionic has significantly lower pressure losses (average 385 Pa). The simulation of the electrical properties of PV/T with all three absorber types showed the highest average solar-to-electrical efficiency (14.5%) in the case of the bionic absorber compared to the PV/T with parallel and serial absorbers (14.4% and 14.3%, respectively). Finally, a set of experiments using the ST, PV and PV/T2 (the index 2 denotes a PV/T collector variant with a foil thickness of 0.3 mm, compared to the thickness of 0.4 mm for PV/T1, positioned between the absorber and the PV cells) modules showed that the PV module, coupled with a bionic absorber plate, achieves the highest average electrical (PV – 8.5% vs. PV/T2 – 9.9%) and exergy (ST – 4.4% vs. PV – 9.2% vs. PV/T2 – 12.7%) efficiencies. Only in terms of the thermal efficiency, the PV/T is at a disadvantage to the ST (PV/T2 – 33.5% vs. ST – 61.4%) due to the air gap between the front glass and the absorber of the latter module.
关键词： Simulation,Solar,Roll-bond heat exchanger,Absorber,Exergy,PV/T
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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Assessment of the cost reduction potential of a novel loop-heat-pipe solar photovoltaic/thermal system by employing the distributed parameter model
摘要： A novel micro-channel loop-heat-pipe solar photovoltaic/thermal (LHP- PV/T) system is developed employing the co-axial tubular heat exchanger as the condenser and upper-end liquid header with tiny holes as the liquid feeder. The design facilitates an easier connection among the solar modules. It creates the improved condensation and separate evaporation effects within the LHP. A reduced evaporator area will thereby have a minor impact on the overall heat transfer performance, leading to significant potential for cost reduction. A distributed parameter model is established and validated by experimental data. The model is then applied to analyze the cost reduction potential of the LHP- PV/T via the optimization of geometrical and structural parameters. The impact of the area reduction on the LHP evaporator differs from that on the traditional integral heat pipe PV/T. The decrements in thermal and electrical efficiencies of the LHP- PV/T are 2.47% and 0.03% respectively when the width of heat pipes in the evaporator decreases from 26 to 10 mm. When the number of heat pipes decreases from 30 to 6, the decrements in thermal and electrical efficiencies are 4.63% and 0.12%, whilst the overall system cost drops by 28.58%, thus the cost-effectiveness of the system can be improved.
关键词： Co-axial tubular heat exchanger,Photovoltaic/thermal,Cost,Loop-heat-pipe,Micro-channel
更新于2025-09-19 17:13:59
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Exergy analysis of a photovoltaic thermal system with earth water heat exchanger cooling system based on experimental data
摘要： In this paper, an attempt has been made to evaluate the experimental exergetic assessment of photovoltaic/thermal (PV/T) system with novel cooling technology termed as earth water heat exchanger (EWHE) cooling. The exergetic efficiency is calculated by considering of exergy destructions and exergy losses. It was observed that the total exergetic efficiency of PV/T is the function of mass flow rate of cooling water for a given solar radiation. The exergetic efficiency of the PV/T system is calculated in three ways, Case I: excluding exergy losses, Case II: including both exergy losses and exergy destructions and Case III: considering only exergy destructions. The results of all the cases were compared and it was found out that the exergetic efficiency of PV/T in Case III was more than the other two cases and it lies between 24.95% to 25.85% and 24.30% to 25.57% for the flow rate of 0.017 kg/s and 0.025 kg/s respectively.
关键词： earth water heat exchanger,EWHE,photovoltaic,PV/T,exergy,solar energy
更新于2025-09-16 10:30:52
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Solar Engineering of Thermal Processes, Photovoltaics and Wind || Flata??Plate Collectors
摘要： A solar collector is a special kind of heat exchanger that transforms solar radiant energy into heat. A solar collector differs in several respects from more conventional heat exchangers. The latter usually accomplish a fluid-to-fluid exchange with high heat transfer rates and with radiation as an unimportant factor. In the solar collector, energy transfer is from a distant source of radiant energy to a fluid. The flux of incident radiation is, at best, approximately 1100 W∕m2 (without optical concentration), and it is variable. The wavelength range is from 0.3 to 3??m, which is considerably shorter than that of the emitted radiation from most energy-absorbing surfaces. Thus, the analysis of solar collectors presents unique problems of low and variable energy fluxes and the relatively large importance of radiation.
关键词： wavelength range,radiant energy,fluid,heat exchanger,solar collector
更新于2025-09-16 10:30:52
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Experimental Investigation of a Novel Solar Micro-Channel Loop-Heat-Pipe Photovoltaic/Thermal (MC-LHP-PV/T) System for Heat and Power Generation
摘要： This paper aims to experimentally investigate a novel solar Micro-Channel Loop-Heat-Pipe Photovoltaic/Thermal (MC-LHP-PV/T) system which, making its first attempt to employ the co-axial tubular heat exchanger as the condenser, PV-bound multiple micro-channel tubes array as the PV/evaporator, the upper end liquid header with tiny holes as the liquid header and liquid/vapour separator, and the upper end vapour header as the vapour collector and distributor, can create the improved condensation and evaporation effects within the loop-heat-pipe (LHP) and thus, achieve significantly enhanced solar thermal and electrical efficiencies compared to traditional PV/T systems. Based on the results derived from our previous analytical study, a prototype MC-LHP-PV/T system employing R-134a as the working fluid was designed, constructed and tested, and the testing results were used to evaluate its operational performance including solar thermal and electrical efficiencies and their relevant impact factors. It is found that solar thermal efficiency of the MC-LHP-PV/T system varied with the inlet temperature and flow rate of coolant water, ambient temperature, as well as height difference between the condenser and evaporator. A lower inlet water temperature, a higher water flow rate, a higher ambient temperature, and a larger height difference between the condenser and the evaporator can help increase the solar thermal efficiency of the system. Under a range of testing conditions with the refrigerant charge ratio of 30%, a peak solar thermal efficiency (i.e., 71.67%) happened at solar radiation of 561W/m2, inlet water temperature of 18°C, water flow rate of 0.17m3/h, ambient temperature of 30°C, and height difference of 1.3m. This set of parametrical data is therefore regarded as the optimal operational condition of the MC-LHP-PV/T system. Under these specific operational condition and the real weather solar radiation, the solar thermal efficiency of the system was in the range 25.2% to 62.2%, while the solar electrical efficiency varied from 15.59% to 18.34%. Compared to the existing PV/T and BIPV/T systems, the new MC-LHP-PV/T system achieved 17.20% and 33.31% higher overall solar efficiency.
关键词： Co-axial tubular heat exchanger,Thermal efficiency,Electrical efficiency,Solar,PV/T,MCLHP
更新于2025-09-16 10:30:52