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Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A thermal insulation plastic greenhouse has been widely used in China, due to the cost-saving, ease to build, and heat preservation. The original heat preservation can be maintained for the air temperature and CO2 concentration in the insulation plastic greenhouses with the large span double arch and double membrane. In this study, an active ventilation fermentation heating and supplemental gas system (AVFHSGS) was designed to control the ventilation time in the asymmetric insulation plastic greenhouse. The system included a fermentation tank (long × wide × height: 7.0 m × 2.0 m × 2.0 m), an air-permeable plate, filter, air replenishment, and sprinkler irrigation device. A field experiment was carried out, where the cow dung, wheat, corn, and tomato straw were taken as the raw materials, and the ratio of cow dung to straw was 3:1 for the active ventilation in aerobic fermentation. There was a large annual output of livestock and poultry manure, together with the straw in China, where the raw materials for biomass fermentation were cheap and accessible. Moreover, the biological oxidative fermentation was often accompanied by the generation and release of a large amount of heat and carbon dioxide. The released heat during composting was diffused into the environment in the form of waste heat, where CO2 was the raw material for photosynthesis. A high concentration of CO2 was selected to accelerate the net photosynthesis of tomato leaves and bloom, which was essential to the supplement gas fertilizer in the process of crop growth and development. An evaluation was made on the heat source and CO2 gas source for the thermal insulation plastic greenhouses, considering the temperature variation of composting fermentation in the shed, the CO2 supplement, and the diffusion of harmful gases, such as NH3, N2O, and CH4. The results showed as follows. 1) The reactor temperature in the AVFHSGS was above 50 for 30 days ℃ ℃ in total, and 55 for 17 days in total, which met the requirements of the Chinese standard for the harmless feces; 2) The air temperature increased by 1-3 at night in the ℃ experimental plastic greenhouses, indicating the better heat source, compared with the control; 3) The average CO2 concentration in the 182 m² measurement area increased to 1 997 μmol/mol by the release of CO2 gas during composting, and the average CO2 concentration in the measurement area was 1 099 µmol/mol during the whole measurement period, the optimal concentration of CO2 increased in the tomato production was 1 000 μmol/mol, meeting the requirement of tomato concentration; 4) The concentrations of NH3, N2O, and CH4 varied from 5.7 to 18.5 μmol/mol, 1.0 to 2.4 μmol/mol and 115 to 315 μmol/mol in the test area, respectively, indicating that there was no outstanding influence or harm on the human health and crop growth. The AVFHSGS can be used as the heat source of insulated plastic greenhouse and CO2 source of crop growth. [ABSTRACT FROM AUTHOR]

In order to analyze the effects of different rearing systems and stages on the vocalization of laying hens, and to provide reference for further establishment of a healthy breeding assessment system based on the vocal information from laying hens, the vocalization of laying hens was monitored in this study. The acoustic characteristics of hens raised under cage and perch systems, at the growing stage and laying stage were studied. The experiment was conducted with the same batch of hens (starting from 86 days of age), which had similar body weights (average 1.1 kg) and health conditions. Those laying hens were randomly divided into two groups: 55 layer raised in the perch system and 25 layers in the cage system. The vocalizations of the laying hens were regularly collected from 13 weeks to 42 weeks of age, using National Instruments' PXI-1050 sound measurement system. The captured sounds were analyzed through pre-treatment, feature extraction and data mining algorithms. The spectrum parameters including duration, amplitude, peak frequency, frequency centroid had been used for statistical analysis. The results showed that the typical laying hen's voice could be classified into four types: egg-laying call, singing call, screaming call and fighting call. There were some differences in the vocal recognition process, with overall high recognition accuracy for egg-laying calls (93%), and moderate prediction rate for singing calls (89%), screaming calls (83%) and fighting calls (75%). Most of the sound signals associated with laying eggs are concentrated in the 0.3-20 s range, with peak frequencies in the 2 500-3 500 Hz. The sound signal of the screaming and fighting calls varies from 0.2 to 1.7 s, with the peak frequency mainly ranging from 500 to 4 000 seconds. Singing calls have a wide range, lasting between 0.2-12 seconds, and peak frequency ranging from 1 000-4 000 Hz. Compared with laying hens at the growing stage, the duration of vocalization of laying hens at the laying stage was longer, and the values of peak frequency and spectral centroid were decreased, while the sound pressure was slightly increased. It was also found that the peak frequency of laying hens' vocalization was negatively correlated with their age increasing. At 14 weeks of age, the average peak frequency was (2 192±320) Hz; while the average peak frequency was (1 550±345) Hz at 41 weeks of age. The peak frequency decreased by about 44 Hz per week during the growing period and about 15 Hz per week during the laying period. Compared with hens in the cage system, hens in perch system produced more sounds, especially egg-laying and singing sounds. The sound energy of laying hens in perch system was also greater than that of laying hens in cage system. The welfare orientated environment leads to an increase in the frequency of hens’ calls, which may also indicate that their vocalization plays a role in natural behavioral expression and social interaction signals. The amount of laying hens call can be used as an indicator to evaluate the welfare of laying hens. In addition, the sound energy of laying hens at night was basically stable (around 1.0 V2 ·s), unless there were abnormal conditions. According to this phenomenon, the change of acoustic energy amplitude of laying hens can be used as a threshold to monitor and warn the abnormal situation in the laying hens' house during night. [ABSTRACT FROM AUTHOR]

A thermal insulation material has widely been used to cover the roof of a greenhouse at night for an energy-saving production of indoor heat. The current mainstream winding of thermal insulation is fixed at the top of a roof, while movable at the bottom. However, there is often a shadow zone indoors during the daytime, when the thermal insulation staying on the top of the greenhouse. This study aims to clarify the changing characteristics of the shadow zone during the year, thereby determining the influence of the shadow zone on the growth of tomatoes. An asymmetric thermal insulation plastic greenhouse was utilized as the test object with a span of 18.0 m (inner span of 16.6 m), the length of 70.0 m, and the ridge height of 6.0 m (inner ridge height of 5.2 m) in Yangling, Shaanxi Province of China. In the east-west direction of the greenhouse, the control area (CK) was set as the 11.26 m projection width of the inner south roof (the projection width of the outer south roof was 12.0 m), while, the test area (TS) was 5.35 m projection width of the inner north roof (the projection width of the outer north roof was 6.0 m). The variation of shadow zone was calculated in the indoor cultivation area during the year, according to the trigonometric relationship between the direct sunlight and the thermal blankets on the roof. A solar radiation sensor was used to capture the solar radiation of TS and CK cultivation areas. The plant height and stem thickness of tomatoes in different cultivation areas were measured using tape measure and vernier caliper, respectively. A LI 6800 system was also utilized to measure leaf photosynthetic parameters, including the net photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency of tomato leaves. Finally, the yield and quantity of tomato fruit were also measured to compare. The results showed that: 1) Compared with the CK area, 38.9% and 27.9% of solar radiation in the TS area were blocked on sunny and cloudy days, respectively. 2) The shadow zone was formed in the indoor cultivation area from February 26. The area of the shadow zone reached the maximum of 146.8 m2 on March 29, accounting for 13.2% of the total cultivated area. Furthermore, the area of the shadow zone began to decrease on September 12 until it reached zero on October 14. The number of days with the shadow zone in the cultivation area was 231 d, accounting for 63.3% of the total number of days in the year. 3) Plant height and stem thickness of tomatoes in the TS area were significantly lower than those in the CK area from 33 days after planting. 4) The net photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency of tomatoes in the TS area were significantly lower than those in the CK area. 5) The average fruit weight per plant, the fruit number per plant, and the average fruit yield per plant in the TS area were 10.5%, 21.3%, and 29.5% lower than those in the CK area, respectively. [ABSTRACT FROM AUTHOR]

Solar radiation is an important parameter affecting light and thermal environment in solar greenhouse. Accurately obtaining the solar radiation value and variation of the interior wall and ground in the greenhouse can play an important guiding role in greenhouse design, construction, environmental regulation and crop production. On the basis of summarizing the previous models of solar radiation, a relatively perfect solar radiation model of solar greenhouse was established in this paper. Meteorological data, the laws of the earth and the movement of the sun, and the relationship between the sun's rays and the angle of the front roof were all considered in this solar radiation model. Internal radiation change of the greenhouse was analyzed based on the model. The model was verified in typical sunny days. The results showed that there were some differences between the calculated and measured solar radiation values, the MBE(mean bias error) was 63.46 W/m2, the MAE(mean absolute error) was 63.48 W/m2, the RMSE(root mean square error) was 79.18 W/m2 and the coefficient of determination R2 was high, ranged from 0.95 to 0.99. The model can be used to calculate the solar radiation intensity of the wall and the ground of solar greenhouse in any area anytime. Highly accurate analysis of the radiation change and the variation of light transmittance in the greenhouse in different seasons were achieved in this paper. It was found that the light transmittance is more affected by the solar azimuth and the solar elevation angle than by the roof angles at different positions. The solar radiation on the surface of the wall and the ground in greenhouse changes with the seasons. The spring equinox and autumn equinox are the days in which the wall and the ground received the longest solar radiation during the year. At this time, the surface of the wall is roughly equivalent to the solar radiation on the ground. From the spring equinox to the autumn equinox, the ground radiation is higher than the surface radiation, while it is opposite when it comes from the autumnal equinox to the vernal equinox. The daily accumulation of solar radiation on the wall changed little from the winter solstice to the start of spring, decreased from the start of the spring to the summer solstice and rose from the summer solstice to the start of winter. The time from winter to the start of the spring is the main production season in the greenhouse, and the heat accumulation of the wall is also the highest in the whole year. Therefore, it is of great significance to carry out research on the heat storage at this stage. Solar radiation in greenhouses in different regions is mainly affected by latitude. In lower latitudes, the amount of solar radiation in winter is large and the amount of radiation in summer is small. The research results can provide reference and related data for the study of wall heat storage, roof optimization, crop planting and energy balance of envelope in solar greenhouse. In addition, the change rule of solar radiation in greenhouse was analyzed just under clear and cloudless conditions. For the plant canopy shade, radiation under different weather conditions, insulation quilt position, different rear roof incline angles and lengths, azimuth angles, wall inclined angle and other aspects of the solar radiation change inside the greenhouse can be further explored by the method proposed in this paper. [ABSTRACT FROM AUTHOR]

The performance of greenhouse wall thermal storage and release capacity depends on the characteristics of the wall material and the thickness of the thermal storage layer. Determining the thickness of the solar greenhouse thermal storage layer is of great significance for promoting the improvement of the solar greenhouse wall. Parametric model according to the actual size and correlation of the test greenhouse was created based on the solar radiation and air temperature. Thickness of the wall thermal storage layer in different months was simulated in this study. In this paper, January 9th, February 9th, March 6th, and April 6th, 2018 in Urumqi was selected as typical sunny days. The solar radiation on the greenhouse floor and wall surface were used as the input condition, and the outdoor air temperature was the boundary conditions. The internal temperature field including each depth of 0, 10, 20, 30, 40, 50 cm of the greenhouse wall from 9:00 to next day 9:00 were simulated by using Autodesk CFD software. In order to ensure the consistency of CFD geometric models within one day and full release of heat from the greenhouse wall at night, no covering insulation quilt was carried out during the greenhouse test. The accuracy of simulated values was verified by comparing with the measured values. The results showed that the simulation results of the greenhouse wall were agreed well with the test results. The average error of each layer on January 9th, February 9th and March 6th was below 1.5 °C. The error and simulated results lags between the test results and the simulated results on April 6th is large. The trend becomes more pronounced as the depth and wall temperature increased. Under the combined influence of greenhouse wall materials, structures, and light and temperature environments, greenhouse wall heat transfer is a complex unsteady process. The brick wall greenhouse was similar to the soil wall greenhouse. The wall could be divided into “insulation layer, stable layer and heat storage layer”. The thickness of each layer was related to the thermal properties of the wall heat storage material and insulation material. The wall temperature fluctuation was more obvious in the depth range of 0-30 cm according to the temperature field of the wall, the temperature attenuation factor of each layer and the delay time. When the wall depth was more than 30 cm, the greenhouse wall temperature fluctuations was relatively flat and the amplitude is small. As the temperature rose, the internal temperature of the greenhouse wall increased overall, and the temperature fluctuations of the various layers were small. The thickness and fluctuation of the greenhouse heat storage layer were less affected by the external light and temperature environment in the case of the greenhouse structure and insulation performance unchanged. In summary, it was feasible to simulate the change of greenhouse wall temperature field. It was reliable that the thickness of greenhouse wall thermal storage layer determined according to the temperature field variation of greenhouse wall. Solar greenhouse temperature environment dynamic simulation model based on greenhouse structure parameters and environmental parameters also could be established in other regions through the methods provided in this paper. It can provide basis and reference for the improvement and optimization of greenhouse wall structure. [ABSTRACT FROM AUTHOR]

Chinese solar greenhouse(hereafter CSG) is an efficient energy-saving greenhouse, and plays an important role in Chinese protected horticulture development. Active thermal storage back wall of CSG has excellent effect of energy storage. However, the hygrothermal performance of active thermal storage wall should be studied further. In this paper, heat transfer characteristics of active heat storage wall with different structures were studied. The CSG with traditional active heat storage wall (hereafter G1) and CSG with backfill-assembled active heat storage wall (hereafter G2) was introduced for experiment based on the operation experiments of heat loss of CSG. The humiture of inlet and outlet, the surface heat flux, temperature and humidity of experiment CSG had been tested. And the heat transfer characteristics were also studied. The results showed that the wind speed at outlet of G1 was 2.82 m/s, significantly higher than that of G2. However, the wind speed of inlet of G1 was smaller than that of G2. Under continuous sunny conditions, the average temperature difference between inlet and outlet of G1 and G2 were 10.2, 11.6 °C, respectively, in the case of active thermal storage conditions; and the average temperature difference between inlet and outlet of G1 and G2 were 3.2 and 3.0 °C respectively, in the case of heat release conditions. Under continuous cloudy conditions, the average temperature difference between inlet and outlet of G1 and G2 were 1.8 and 2.3 °C respectively, in the case of heat release conditions; and the exothermic heat flux of G1 and G2 were 7.48 and 5.66 W/, respectively. The heat transfer characteristic of heat storage circulation system of active thermal storage wall were be analyzed. Research shows that the average heat exchange amount of G1 and G2 were 120.36 and 215.27 MJ, respectively, under continuous sunny conditions. And the energy efficiency ratio of G1 and G2 were 15.48 and 49.83, respectively. Therefore, the heat storage amount of G2 had a dramatic improvement compared to G1. The G2 had a better energy saving effect. Under continuous cloudy conditions, the G2 released more heat compared to G1. In the typical sunny day, the passive heat storage amount of back wall of G2 was 46.9% higher than G1 during the heat storage process and it was similar for both G1 and G2 during the heat release process. In the typical cloudy day, the passive heat storage amount of back wall of G2 was 46.4% higher than G1 during the heat storage process while the passive heat release amount of back wall of G2 was 26.2% lower than that of G1. In typical sunny day, the heat storage contributions of G1 and G2 were 30.02% and 34.32%, respectively and the heat release contributions of G1 and G2 were 27.38% and 39.35%, respectively. In typical cloudy day, the heat release contributions of G1 and G2 were 36.41% and 44.01%, respectively. Our study showed that the G2 had higher long-term heat storage capacity, and G2 would facilitate to maintain inner humiture stability of CSG under the long-term low temperature and cloudy conditions. This paper can provide a theoretical and practical guidance to thermal load design of CSG with active thermal storage system. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Chinese energy-saving solar greenhouse originated from the southern of Liaoning Province, which had fully independent intellectual property right, and played an important role in protected horticulture. Although Chinese solar greenhouse has rapidly developed more than 30 years, insufficient heat preservation and thermal storage and poor environment control ability caused by unreasonable greenhouse structure still exist in Chinese solar greenhouse. Therefore, to optimize the energy conservation of Chinese solar greenhouse is needed urgently. Soil, wall and skeleton in Chinese solar greenhouse can realize the thermal storage during the day and thermal release during the night. Compared to passive storage, the thermal storage of Chinese energy-saving solar greenhouse can provide more heat energy for greenhouse through the transformation of sunlight by materials, structures and equipment. Based on solar energy source, by means of mechanical power equipment, active heat storage uses indoor soil, wall, frame structure, and phase change materials as heat absorbing medium to accumulate heat, and the opposite is passive heat storage. The heat of active/passive storage all comes from the sunlight, and there are 2 ways to use the heat. One is to maximize the use of the indoor captured solar energy or indoor surplus heat, and the other is to use outdoor solar energy. Currently there are many thermal storage forms, such as active lighting thermal storage, air circulation thermal storage, water circulation thermal storage, phase change material thermal storage, pebble thermal storage, heat pump thermal storage, combined thermal storage. Through the adjustment of the tilting roof angle in active lighting thermal storage greenhouse, more solar energy is gotten indoors, so that the indoor heat accumulates more. Air circulation thermal storage means excess thermal energy is stored into the underground soil or wall, including underground air circulation storage and wall air circulation storage. Water circulation thermal storage uses water as the thermal storage body, and the water accumulates heat during the day, and releases heat during the night, including water curtain heat storage and pipeline water heat storage. Phase change material thermal storage uses phase change material as the thermal storage body, and its strong thermal storage capacity is used to provide indoor heating. Pebble thermal storage uses pebble as the thermal storage body, and its strong thermal storage capacity is used to provide indoor heating. Heat pump thermal storage uses electricity to convert the low-grade heat energy extracted from air, water or soil into high-grade heat energy for indoor heating. The heat pump is divided into 3 types: water source heat pump, air source heat pump and soil source heat pump. Combined thermal storage is the combination of 2 or more thermal storage methods for indoor heating. This paper reviewed the relevant research results of heat storage technology in solar greenhouse, analyzed the main technical problems and research emphasis, prospected the future development direction and the research content from 4 aspects, i.e. traditional solar greenhouse transformation, new structure development, technology integration of the research method in heat storage and application of heat storage greenhouse, and provided reference for the heat storage research of energy-saving solar greenhouse in China.. [ABSTRACT FROM AUTHOR]

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Transactions of the Chinese Society of Agricultural Engineering is the property of Chinese Society of Agricultural Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The typical Chinese solar greenhouse, compared to other types of greenhouse, has the properties of low construction cost and low energy consumption when operating during winter days, which draws the attention of the researcher in the field of facility horticulture. In recent years, the structural parameters, such as span, ridge height and wall thickness in Chinese solar greenhouse have been extensively studied. However, the correlation relationship between reasonable back roof projection width (BRPW) and northern wall height (NWH) have always been inconsistent and require further investigation. In this study, a new method for calculating BRPW and NWH was obtained based on the reasonable periods where the northern wall surface receive direct solar radiation in different latitude regions. Firstly, the average monthly lowest temperature and the average monthly highest temperature were statistically analyzed in some cities from January to June in 1998-2012. The data showed that when the average monthly lowest temperature was close to or exceeded 0 ℃, the average monthly highest temperature was close to or exceeded 30 ℃. Therefore, combined with the traditional Chinese solar knowledge, it is suggested that when the average monthly lowest temperature was lower than 0 ℃, it was necessary to ensure that at least part of the northern wall can receive direct solar radiation between 10:00 to 14:00 each day. Based on this, the reasonable periods where the northern wall surface received direct solar radiation in Chinese solar greenhouse in different latitude regions were obtained. Then according to the change of the sun direct light in the reasonable periods, the method for calculating BRPW and NWH in Chinese solar greenhouse was obtained. The NWH of solar radiation, which were observed at 10:00 am on winter solstice, in the solar greenhouses with different spans, were calculated by using the typical structure parameters of Chinese solar greenhouse in previous studies. The effects of thermal environment analysis were in accordance with the results in literatures. The utilization of the method for modeling the NWH of solar radiation in the well-known Shouguang solar greenhouse in various date confirmed that the actual period where the northern wall accept the direct solar radiation was close to the reasonable period proposed in this study, further suggesting the feasibility of this method. The method has been used to calculate the front roof lighting angle, ridge height, BRPW and NWH in solar greenhouses with various spans in different cities in China. The ratio of BRPW to the span in solar greenhouse ranged from 0.04 to 0.23, which varied in in geographic locations and climatic conditions. When the climatic conditions in different areas were similar, the increase of latitude resulted in an increase of BRPW. The areas with lowest BRPW ratio (0.04 to 0.11) were located in Taiyuan, Xi’an, Lanzhou, Xining, Yinchuan and other low-latitude cold regions. These results suggested that the BRPW can be slightly decreased in cold areas and appropriately increased in warm regions. This method can provide theoretical guidance for optimal design of solar greenhouse in China. [ABSTRACT FROM AUTHOR]

The Chinese solar greenhouse is a typical greenhouse without heating system, in which the heat insulating layer and the defect of air tightness of the envelope structure are the major factors affecting insulation and heat storage performance. Compared with temperature measurement method of single point, the thermal infrared imaging technology can be used to measure the temperature of the whole area, which can be seen in the form of a color picture. Therefore, the thermal infrared imaging technology can be used as an effective method to detect temperature difference area. The purpose of this study is to develop an efficient method to detect and quantitatively analyze the area of thermodynamic disfigurement in solar greenhouse. The tested solar greenhouse, with length of 52 m and width of 8 m, locate in Yangling, Shanxi province (108°4′E, 34°16′N). The north wall of solar green house, equipped with 16 ventilation vents, was structured by clay-brickwith width of 1 m and polystyrene board with width of 10 cm. E4 thermal mapper, which was perpendicular to the north wall with a distance of 1.5 m, was used to obtain infrared images of the north wall in solar greenhouse. The data that were collected in a typical sunny day (from Dec. 15, 2015, 15:30 to 16:30, the heat insulation sheet was rolled down at 16:30) were used to analyze the accuracy of different area measurement methods. FLIR Tools software was used to extract temperature data in thermal infrared image of the north wall. LabVIEW 13.0 software was used to read and select the interested infrared image area, and the corresponding temperature data were imported. Root mean square (RMS) and histogram were used to set different temperature thresholds. The measured data and calculated data from different area measurement methods were compared. The results showed that the temperature of different regions of the north wall in solar greenhouse can be displayed in the thermal infrared images, the surface temperature of the ventilation vent was lower than the inner surface temperature of northern wall, and the maximum temperature difference was up to 8.4 ℃. Locations of thermodynamic disfigurement could be quickly detected and positioned. The histogram of thermal infrared image showed that the surface temperature of thermal region and the proportion of the temperature interval had a gradual increase and then a decrease after reaching the peak point, and finally a sudden increase. In these three types of the area measurement methods, histogram method showed best results with the minimum average relative error (ARE) of 5.4%, followed by manual extraction method with ARE of 6.0% and the RSM method with ARE of 11.8%. Based on these results, an efficient method for measuring the area of the thermal region in solar greenhouse was developed to quantitatively analyze the entire thermodynamic disfigurement area and the value of the heat loss in solar greenhouse, which will help the further optimization of the solar green house and supply constructive recommendations for farmers and business leaders. [ABSTRACT FROM AUTHOR]