Performance of Solar Utilization System Developed with Capillary Tube Mats to Collect and Release Heat in Chinese Solar Greenhouses

2020 ◽  
Vol 36 (2) ◽  
pp. 167-174 ◽  
Author(s):  
Ming Li ◽  
Liwei Yue ◽  
Weitang Song ◽  
Chaoyuan Wang
Keyword(s):  
Solar Energy ◽  
Air Temperature ◽  
Indoor Air ◽  
Heat Insulation ◽  
Capillary Tube ◽  
Water Tank ◽  
Capillary Tubes ◽  
The North ◽  
North Wall ◽  
Heat Released

HighlightsA solar utilization system was developed with capillary tube mats (SUSCTM) to heat Chinese solar greenhouses (CSGs) actively during winter nights.In the solar day, SUSCTM collected 28~33% of the accumulated solar energy on the north-wall and released 40.3~48.6% of the collected heat in night under the experimental conditions.The thermal performances of SUSCMT can be further improved by improving the heat insulation of the water tank, doubling and elongating the capillary tubes.Abstract.A solar utilization system composed of capillary tube mats, a water tank, recirculating pipes, and a pump (SUSCTM) was developed to improve the temperature of Chinese solar greenhouses (CSGs) during winter nights. The capillary tube mats were mounted on the north-wall to intercept solar radiation. By circulating water within the SUSCTM during the daytime, the solar energy can be absorbed and stored in the water tank. In the same way, the heat stored in the water tank can be recovered to increase the indoor air temperature (Tin) in the night. During the daytime hours of sunny days, SUSCMT stored the heat of 102.4~135.4 MJ under the test conditions, which accounts for 28~33% of the accumulated solar energy on the north wall. The heat released by the SUSCTM during the nighttime hours of sunny days accounted for 40.3~48.6% of the collected heat. As a result, the minimum Tin in the night was elevated by 1.6°C~1.9°C, with the coefficient of performance (COP) of 1.3~1.8. On the other hand, the SUSCMT only operated during the night hours of cloudy day and elevated the minimum Tin by 1.5°C. The COP was 1.2 as a result. In addition, the amount and flux of heat released by the SUSCMT per the north wall area matched the conventional north wall of CSGs. Based on the proposed model, the thermal performances of SUSCMT can be further improved by improving the heat insulation of the water tank, doubling and elongating the capillary tubes. Thus, the SUSCMT has the potential to increase the Tin of CSG during winter nights. Keywords: Capillary tube mats, Chinese solar greenhouse, Indoor air temperature, Solar utilization system, Water circulation.

Feasibility of Employing a Heat Insulation Wall as the North Wall of a Chinese Solar Greenhouse in a Severely Cold Area of China

2019 ◽  
Vol 35 (6) ◽  
pp. 903-910
Author(s):  
Ming Li ◽  
Pingzhi Wang ◽  
Weitang Song
Keyword(s):  
Heat Loss ◽  
Air Temperature ◽  
Heat Insulation ◽  
Environmental Damage ◽  
The North ◽  
Solar Greenhouse ◽  
Cold Area ◽  
North Wall ◽  
Insulation Wall ◽  
The Impact

Abstract. The conventional north wall of a Chinese solar greenhouse (hereafter referred to as a “solar greenhouse”) can release heat inside and help maintain a high indoor air temperature (T) during winter nights. However, the construction of conversational walls face problems of high cost, low construction quality, environmental damage, etc. Based on this, heat insulation walls have aroused much interest. However, this kind of wall can barely store and release heat, putting the solar greenhouse at risk of low T. The purpose of this study is to investigate whether the impact of the heat insulation wall could be weakened by decreasing the heat loss through the greenhouse envelope. The thermal environment of a solar greenhouse located in a severe cold area of China (Mohe County, Heilongjiang Province) was examined during sunny days, of which the north wall was constructed from polystyrene boards and plastered with 10 mm-thick mortar. During the experiment, the outdoor air temperature (T) was -22.8±5.6°C during the night, reaching a low of -34.7°C. The amount of heat released from the north wall can be neglected, as it was 5.4% of the total heat obtained by the test solar greenhouse. In comparison with conventional solar greenhouses, both heat loss through the building envelope and the heat obtained from the test solar greenhouse during the night decreased. As a result, T was maintained at 10.6±2.9°C, with a low of 6.8°C, during the night, which was within the normal range of a conventional solar house located in northern China. Thus, the impact of the heat insulation wall on T in the sunny days was weakened by decreasing the heat loss through the greenhouse envelope. Nevertheless, more work on the performance of test solar greenhouse on cloudy days and summer days should be conducted to fully validate the proposed hypothesis. Keywords: Chinese solar greenhouse, Heat insulation wall, Heat loss, Indoor temperature.

Design and Application of a Seasonal Solar Soil Heat Storage System Applied in Greenhouse Heating

2014 ◽  
Vol 672-674 ◽  
pp. 21-25
Author(s):  
Liang Zhang ◽  
Peng Xu ◽  
Jia Chen Mao ◽  
Xu Tang
Keyword(s):  
Solar Energy ◽  
Energy Saving ◽  
Air Temperature ◽  
Indoor Air ◽  
Solar Collector ◽  
Heat Storage ◽  
Storage System ◽  
Control Subsystem ◽  
And Control ◽  
Design And Application

A seasonal solar soil heat storage (SSSHS) system applied in greenhouse heating has been designed and introduced. The system consists of solar collector subsystem, soil heat storage subsystem, greenhouse heating subsystem, hydronic subsystem and control subsystem. By applying soil heat storage, solar energy stored in the soil under the greenhouse can be transferred and utilized in winter to realize the utilization of cross-seasonal energy. TRNSYS is used to simulate the process and effect in the system of the solar energy collection and soil heat storage in Shanghai, and the simulation is calibrated to improve the precision of the TRNSYS model. When the indoor air temperature of the greenhouse is kept at 12°C throughout the year, the energy saving by using the SSSHS system in Shanghai can be 46.2kWh/(m2∙year).

scholarly journals Numerical investigation of the north wall passive thermal performance for Chinese solar greenhouse

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3465-3476
Author(s):  
Yiming Li ◽  
Xingan Liu ◽  
Fengsheng Qi ◽  
Li Wang ◽  
Tianlai Li
Keyword(s):  
Solar Energy ◽  
Wall Thickness ◽  
Thermal Performance ◽  
Thermal Environment ◽  
Energy Utilization ◽  
Wall Material ◽  
The North ◽  
Solar Energy Utilization ◽  
Solar Greenhouse ◽  
North Wall

The fully passive solar energy utilization system of Chinese solar greenhouse is efficient for ensuring year-round cultivation of vegetables, owing to the high amount of heat charge and discharge characteristic of the north wall enclosure. In the present research, the thermal performance is investigated using CFD. A 3-D mathematical model has been established to evaluate the wall thickness, layered configuration and material property. The predicted thermal environments are in good agreement with the experimental measurements, indicating the reliability of the established numerical model. The results showed that the increase of north wall thickness could cause the waste of resources due to the thermal masses mainly concentrate in the superficial layer. Constructing layered configuration is rec-ommended for the north wall which uses Styrofoam in the outer layer to reduce heat loss. Nevertheless, the property of north wall material has little effect on the thermal environment. The research results, thus obtained, will give good guidance for completing the Chinese solar greenhouse engineering database and optimizing the solar energy utilization.

A Pilot Study on the Microclimate of a Multi-span Solar Energy Greenhouse

2019 ◽  
Vol 35 (4) ◽  
pp. 601-616 ◽  
Author(s):  
Mengwei Ni ◽  
Dun Lan ◽  
Mohammad Shah Jahan ◽  
Jian Wang ◽  
Shirong Guo
Keyword(s):  
Solar Energy ◽  
Energy Saving ◽  
Air Temperature ◽  
Natural Ventilation ◽  
Thermal Environment ◽  
Winter Season ◽  
Soil Surface ◽  
Cost Effective ◽  
Effective Accumulated Temperature ◽  
North Wall

Abstract. Extreme low and high temperature is the main obstacle to grow plants in an ambient environment. Due to climate change, these problems are getting worse day by day. To resolve this dilemma a new type of energy-saving greenhouse structure, a multi-span solar energy greenhouse (SEG), was designed and constructed in the Yangtze valley region of China. Using a multi-span plastic greenhouse as a control greenhouse (CG), the microclimate characteristics of the SEG were studied in winter and summer. The results showed that, because the SEG adopted the cooling way of the combination of external shading and natural ventilation in summer, on a sunny day and cloudy day, the average air temperature of the SEG were 3.9°C and 0.9°C lower than CG, respectively, the average solar transmittance were 40% and 18% lower than CG, respectively, indoor microclimate distribution was more uniform. In an acute temperature condition, the effect of natural ventilation on cooling inside the SEG was better than CG during the daytime. Additionally, during the winter season, on a sunny day and cloudy day, compared with CG, the average solar transmittances of the SEG were 24% and 12% lower than CG, respectively, at the same time, the average air temperature of the SEG were 2.1°C and 2.3°C higher than CG, respectively. During the nighttime, the soil surface as well as the film temperature of the SEG, was higher than CG, whether it was on a sunny or a cloudy day, the daily effective accumulated temperature in SEG was more than CG. A north wall was built inside the SEG could effectively improve indoor nighttime temperature, and per unit volume of the SEG could save 0.63 L of diesel per day in winter, thereby saving $0.53, and reducing carbon emissions by 1.74 kg. Taken together, considering all aspect we concluded that the indoor environment of the SEG was more suitable for plant growth and cost-effective for crop cultivation as well. Keywords: Energy-saving, Greenhouse, Microclimate characteristics, Solar energy, Thermal environment.

scholarly journals Coupling Effect of Space-Arrangement and Wall Thermal Resistance on Indoor Thermal Environment of Passive Solar Single-Family Building in Tibet

2019 ◽  
Vol 9 (17) ◽  
pp. 3594 ◽  
Author(s):  
Xiaoling Cui ◽  
Yangkai Zhang ◽  
Guochen Sang ◽  
Wenkang Wang ◽  
Yiyun Zhu ◽  
...  
Keyword(s):  
Solar Energy ◽  
Thermal Resistance ◽  
Air Temperature ◽  
Indoor Air ◽  
Thermal Environment ◽  
Living Room ◽  
Single Family ◽  
Indoor Thermal Environment ◽  
Building Model ◽  
Passive Solar

In areas where solar energy is abundant, such as the Tibetan plateau, passive solar buildings are attracting more and more attention and becoming a popular form of rural building. However, it is often difficult to achieve the satisfactory indoor thermal environment in a local rural passive solar single-family house. In order to improve the indoor thermal environment of passive solar buildings through building design, a systematic study of rural single-family buildings in Tibet was conducted. The basic parameters were investigated on the outdoor thermal environment, space-arrangement, envelope structure, and the indoor thermal environment. The building model considering space-arrangement modes was developed based on the survey data in multi-space passive solar buildings. The general physical and mathematical analysis models of multi-space passive solar buildings were established based on the heat transfer theory. Furthermore, the effects of space-arrangement and exterior wall thermal resistance on indoor air temperature were analyzed by numerical simulation. Results show that the indoor air temperature of the passive solar building is influenced by space-arrangement and wall thermal resistance together. When the space-arrangement of the building model was changed from “north-south through type” (mode a) to “through and separation combination” (mode b) and “north-south separation” (mode c), the indoor air temperature of the living room increased from 8.8 °C to 10.6 °C and 11.6 °C, with increases of 20.5% and 31.8%, respectively. In addition, equally increasing the thermal resistance of exterior walls in different orientations has different effects on the indoor air temperature. In the space-arrangement mode c, comparing with the temperature increment of the living room and bedroom caused by increasing thermal resistance of the south wall and north wall, the temperature increment of the living room caused by increasing thermal resistance of the east/west wall increased by 151.7% and 32.7%, and that of the bedroom increased by 609.1% and 239.1% respectively. This study can provide a reference for the optimal design of passive solar buildings in solar energy abundant areas.

Simulation of the internal temperature in the Passol Laboratory, University of Debrecen

2012 ◽  
Vol 3 (1) ◽  
pp. 63-73 ◽  
Author(s):  
I. Csáky ◽  
F. Kalmár
Keyword(s):  
Temperature Variation ◽  
Air Temperature ◽  
Indoor Air ◽  
Storage Capacity ◽  
Building Structures ◽  
Internal Temperature ◽  
The One ◽  
Heavy Structure ◽  
East West ◽  
Made In

Abstract Nowadays the facades of newly built buildings have significant glazed surfaces. The solar gains in these buildings can produce discomfort caused by direct solar radiation on the one hand and by the higher indoor air temperature on the other hand. The amplitude of the indoor air temperature variation depends on the glazed area, orientation of the facade and heat storage capacity of the building. This paper presents the results of a simulation, which were made in the Passol Laboratory of University of Debrecen in order to define the internal temperature variation. The simulation proved that the highest amplitudes of the internal temperature are obtained for East orientation of the facade. The upper acceptable limit of the internal air temperature is exceeded for each analyzed orientation: North, South, East, West. Comparing different building structures, according to the obtained results, in case of the heavy structure more cooling hours are obtained, but the energy consumption for cooling is lower.

scholarly journals Detrended Multiple Cross-Correlation Coefficient applied to solar radiation, air temperature and relative humidity

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Andrea de Almeida Brito ◽  
Heráclio Alves de Araújo ◽  
Gilney Figueira Zebende
Keyword(s):  
Relative Humidity ◽  
Solar Radiation ◽  
Solar Energy ◽  
Correlation Coefficient ◽  
Air Temperature ◽  
Cross Correlation ◽  
Global Solar Radiation ◽  
Meteorological Variables ◽  
Hourly Data ◽  
Cross Correlations

AbstractDue to the importance of generating energy sustainably, with the Sun being a large solar power plant for the Earth, we study the cross-correlations between the main meteorological variables (global solar radiation, air temperature, and relative air humidity) from a global cross-correlation perspective to efficiently capture solar energy. This is done initially between pairs of these variables, with the Detrended Cross-Correlation Coefficient, ρDCCA, and subsequently with the recently developed Multiple Detrended Cross-Correlation Coefficient, $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2. We use the hourly data from three meteorological stations of the Brazilian Institute of Meteorology located in the state of Bahia (Brazil). Initially, with the original data, we set up a color map for each variable to show the time dynamics. After, ρDCCA was calculated, thus obtaining a positive value between the global solar radiation and air temperature, and a negative value between the global solar radiation and air relative humidity, for all time scales. Finally, for the first time, was applied $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}$$DMCx2 to analyze cross-correlations between three meteorological variables at the same time. On taking the global radiation as the dependent variable, and assuming that $${\boldsymbol{DM}}{{\boldsymbol{C}}}_{{\bf{x}}}^{{\bf{2}}}={\bf{1}}$$DMCx2=1 (which varies from 0 to 1) is the ideal value for the capture of solar energy, our analysis finds some patterns (differences) involving these meteorological stations with a high intensity of annual solar radiation.

Indoor air temperature modelling: Thermal retrofitting of historical building

2021 ◽  
Author(s):  
Jan Kočí ◽  
Laura Ré Luvisotto ◽  
Jiří Maděra
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Historical Building

scholarly journals Gold Nanoparticles Affect Pericyte Biology and Capillary Tube Formation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Sasikarn Looprasertkul ◽  
Amornpun Sereemaspun ◽  
Nakarin Kitkumthorn ◽  
Kanidta Sooklert ◽  
Tewarit Sarachana ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Endothelial Cell ◽  
Mrna Expression ◽  
Capillary Tube ◽  
Quantitative Polymerase Chain Reaction ◽  
Tube Formation ◽  
Endothelial Cell Proliferation ◽  
Control Group ◽  
Capillary Tubes ◽  
Cell Functions

Gold nanoparticles (AuNPs) are used for diagnostic and therapeutic purposes, especially antiangiogenesis, which are accomplished via inhibition of endothelial cell proliferation, migration, and tube formation. However, no research has been performed on the effects of AuNPs in pericytes, which play vital roles in endothelial cell functions and capillary tube formation during physiological and pathological processes. Therefore, the effects of AuNPs on the morphology and functions of pericytes need to be elucidated. This study treated human placental pericytes in monoculture with 20 nm AuNPs at a concentration of 30 ppm. Ki-67 and platelet-derived growth factor receptor-β (PDGFR-β) mRNA expression was measured using real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell migration was assessed by Transwell migration assay. The fine structures of pericytes were observed by transmission electron microscopy. In addition, 30 ppm AuNP-treated pericytes and intact human umbilical vein endothelial cells were cocultured on Matrigel to form three-dimensional (3D) capillary tubes. The results demonstrated that AuNPs significantly inhibited proliferation, reduced PDGFR-β mRNA expression, and decreased migration in pericytes. Ultrastructural analysis of pericytes revealed AuNPs in late endosomes, autolysosomes, and mitochondria. Remarkably, many mitochondria were swollen or damaged. Additionally, capillary tube formation was reduced. We found that numerous pericytes on 3D capillary tubes were round and did not extend their processes along the tubes, which resulted in more incomplete tube formation in the treatment group compared with the control group. In summary, AuNPs can affect pericyte proliferation, PDGFR-β mRNA expression, migration, morphology, and capillary tube formation. The findings highlight the possible application of AuNPs in pericyte-targeted therapy for antiangiogenesis.

scholarly journals Air Temperature Model Evaluation in the North Mediterranean Belt Area

2002 ◽  
Vol 41 (8) ◽  
pp. 872-884 ◽  
Author(s):  
Julia Bilbao ◽  
Argimiro H. de Miguel ◽  
Harry D. Kambezidis
Keyword(s):  
Air Temperature ◽  
Model Evaluation ◽  
Temperature Model ◽  
The North
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