基于Design+Builder的锯齿型光伏温室光环境仿真与采光屋面优化.pdf

农业生物环境与能源工程 Simulation of light environment in a serrated photovoltaic greenhouse and optimization of daylighting roofs based on Design Builder LIU Jian1 2 3 WU Xuyong2 WANG Baolong1 2 3 WU Qingsen2 TIAN Libo1 2 3 1 Sanya Institute of Breeding and Multiplication Hainan University Sanya 572025 China 2 School of Tropical Agriculture and Forestry Hainan University Haikou 570228 China 3 Key Laboratory for Quality Regulation of Tropical Horticultural Crops of Hainan Province Haikou 570228 China Abstract In the tropical regions represented by Hainan there are abundant solar and thermal resources and it is relatively suitable for the construction of photovoltaic greenhouse PVG However the construction of PVG still relies mainly on experience and is incapable of quantifying the balance between the photovoltaic PV generation and the light requirements for agricultural production As a result actual PVGs are primarily PV based without carefully considering the needs of agricultural daylighting To quantify the influence of the design parameters of PVGs and the layout of PV panels on the internal daylighting of serrated PVGs and to optimize the daylighting design of the roof this paper utilizes the Design Builder software to establish gradient models for a multi span serrated type PVG in tropical regions Gradient models were established in terms of aspects namely span width of longitudinal transverse daylighting strip height roof angle and photovoltaic panel coverage rate PCR Daylighting in the greenhouse of each gradient model was simulated and with the annual average daily light integral ADLI and distribution uniformity DU as evaluation indicators the influence of various design parameters on the daylighting inside the greenhouse was quantified The result reveals that 1 PCR is the decisive indicator for daylighting in the PVG and a function between PCR and the ADLI is derived as ADLI 15 5 PCR 16 841 2 Increasing the width of longitudinal daylighting strip significantly improves the ADLI and enhances DU while increasing the span has a noticeable effect on improving ADLI but does not significantly enhance DU 3 Increasing the eave height without changing PCR does not enhance ADLI but effectively improves DU increasing the transverse daylighting strip and adjusting the roof angle hardly improves ADLI In summary it is recommended that the optimal span for PVGs in tropical regions be set within the range of 6 5 8 0m and the eave height be set within the range of 2 5 3 5m Preferably the longitudinal daylighting strip with a width ranging from 0 5 0 8m should be installed Based on the above relationship function the PCR can be calculated according to the appropriate light demand for the cultivated crops The daylighting design theory proposed in this paper can provide a theoretical basis and reference for the healthy development of the PV industry in tropical regions Keywords photovoltaic greenhouse annual average daily light integral greenhouse design parameters daylighting tropical regions doi 10 11975 j issn 1002 6819 202410056 CLC number S26 1 Documents code A Article ID 1002 6819 2025 07 0211 11 LIU Jian WU Xuyong WANG Baolong et al Simulation of light environment in a serrated photovoltaic greenhouse and optimization of daylighting roofs based on Design Builder J Transactions of the Chinese Society of Agricultural Engineering Transactions of the CSAE 2025 41 7 211 221 in English with Chinese abstract doi 10 11975 j issn 1002 6819 202410056 http www tcsae org 刘建 吴徐勇 王宝龙 等 基于Design Builder的锯齿型光伏温室光环境仿真与采光屋面优化 J 农业工程学报 2025 41 7 211 221 doi 10 11975 j issn 1002 6819 202410056 http www tcsae org Received date 2024 10 10 Revised date 2025 03 03 Fund project 2024 Science and Technology Commissioner Service Group s Emergency Science and Technology Research Project for Wind Disaster Relief in Hainan Province ZDYF2024YJGG002 8 China Huaneng Group Co Ltd Headquarters Technology Project Optimization of Photovoltaic Vegetable Greenhouse Structure and Research on Planting Agronomy in Tropical Regions HNKJ22 HF77 Biography LIU Jian Associate professor research interests Facility Greenhouse Design and Construction Email liujian99 Corresponding author WANG Baolong Ph D Associate professor research interests Facility Agriculture Engineering Email wangbaolong Member of the Chinese Society of Agricultural Engineering LIU Jian E041201041S WANG Baolong B042111008M 第 41 卷 第 7 期农 业 工 程 学 报 Vol 41 No 7 2025 年 4 月Transactions of the Chinese Society of Agricultural Engineering Apr 2025 211 0 Introduction In Hainan typhoons and rainstorms are frequent in summer and autumn Meanwhile there is intense sunlight high temperature and high humidity along with the frequent occurrence of pests and diseases which restrict outdoor vegetable cultivation The planting environment created by greenhouses which features ventilation rain protection and pest prevention minimizes the impact of adverse meteorological factors on agricultural production and serves as an effective means to enhance the local vegetable self sufficiency rate Before the integration of agriculture and photovoltaics PV the construction of vegetable bases mainly relied on financial support Under the condition of limited financial burden most greenhouses were equipped with simple facilities had low structural strength and a short service life The combination of greenhouses and PV can not only introduce enterprise capital to support the construction of vegetable bases and provide more job opportunities for farmers but also improve the design and construction standards of greenhouses for example the typhoon resistance level can be increased and the designed service life can be extended from 5 8 years to 25 years Moreover it can improve the growth conditions of plants inside the greenhouses and reduce the amount of pesticides used In terms of scale PV vegetable bases have already become an indispensable and important components of Hainan s vegetable basket supply guarantee bases The photovoltaic greenhouse PVG employs PV modules as roofing materials partially replacing traditional thin films such as PC modules glass etc forming a dual use model of power generation on the roof and crop cultivation below The initial design intention is to efficiently utilize land space and solar energy However in practical production many problems are hindering the development of PVG such as the long term investment required for agricultural production the risk of yield reduction caused by the shading effect of PV low and unstable agricultural production profits and even the risk of losses In contrast PV power generation is simple to manage with higher and more stable returns As a result many PVGs do not focus on agricultural production leading to abandoned land or instances where greenhouses are touted for planting but serve purely as PV power generation bases 1 3 contradicting the original purpose of PVG development To resolve the conflict between power generation and plant cultivation competing for light resources researchers around the world have conducted targeted cultivation experiments including but not limited to solanaceous 4 8 leafy vegetables 9 10 mushrooms 11 sprouts legumes 12 and flowers in PVG 13 based on the actual conditions and needs of different regions Some excellent crop varieties suitable for cultivation in local PVG have been selected and key technical points for agricultural production in such unique environments have been summarized promoting a balance between PV power generation and agricultural production from the perspective of plant production Researchers have also conducted studies on various aspects such as greenhouse structure 14 15 PV module structure 16 18 PV module layout 19 20 PV module materials 21 23 and thin film materials 24 primarily focusing on enhancing the performance of PVG and minimizing the impact of shading from PV modules on agricultural production In addition to physical greenhouse studies researchers have also used computer simulation software to construct virtual greenhouse models obtaining simulated environmental data for PVG 25 28 and guiding the improvement of PVG structures Both PV power generation and agricultural production are industries highly dependent on natural conditions and research results in each region can only be applied to areas with similar climates Therefore each region needs to develop PVG with regional characteristics in response to local natural environments The tropical regions of China represented by Hainan 18 10 N 20 10 N 108 37 E 111 03 E are known for abundant solar resources high annual temperatures indistinct seasonal boundaries heavy precipitation high humidity and frequent typhoons Combining PV and agricultural facilities PV mounting structure is stable enough to resist typhoons and shading from PV modules can lower temperatures inside the greenhouse Using abundant light resources for power generation in summer can be regarded as a model of efficient utilization of resources 29 However there are no quantitative parameters available for reference in the design and construction of PVG Moreover the daylighting design of PVG mainly relies on the personal experience of designers which has seriously affected the orderly development of PVG This paper aims to establish a large number of simulation models to calculate the specific effects of various structural parameters of PVG in tropical regions on the distribution of the light environment and provide a quantitative conclusion that can guide the design and construction of PVG in tropical regions 1 Methodology and content 1 1 Introduction to simulation software Design Builder is a building environment analysis and simulation software that is secondarily developed based on the Energy Plus engine It has added intelligent control algorithms and comes with the function of optimizing parameters enabling higher precision in simulation This software has extensive and crucial applications in the 212农业工程学报 http www tcsae org 2025 年 simulation of the light environment In terms of illuminance calculation and analysis it utilizes radiance illuminance simulation Taking the visualized 3D geometric model as input and applying the backward ray tracing method it accurately calculates the illuminance on the working plane of buildings and provides detailed illuminance data at different positions In the fields of shading and optimization of natural daylight utilization it can simulate the effects of local shading devices Moreover by simulating the light environment under different time and space conditions it can optimize window design Meanwhile it can simulate the light distribution under different interior space layout schemes and evaluate the uniformity of the lighting environment 1 2 Initial model setup The initial model selects the multi span serrated PVG designed by associate professor Liu Jian from Hainan University 30 The greenhouse adopts a combination roof structure with slopes facing north and south The symmetrical roof structure is uniformly stressed with the center of gravity positioned in the middle which is conducive to resisting wind loads PV modules cover the south slope roof while the north slope roof is covered with translucent film As agricultural facilities in tropical regions only consider cooling needs and have minimal insulation requirements the greenhouse utilizes a staggered ventilation design along the height direction on the north and south slopes to create serrated ventilation openings Additionally insect proof nets are installed at the serrated ventilation opening and on the greenhouse facade to provide both rain and insect protection for crop cultivation and to facilitate air circulation for ventilation and temperature reduction within the greenhouse This structural design has been implemented in several counties and cities in Hainan with good application results The parameters of the PVG are shown in Fig 1 The PV modules are monocrystalline silicon PV modules Model No EG 540M72 HL BF DG with a length of 2 285 m width of 1 134 m and thickness of 35 mm and they are non translucent The power generation efficiency of commercial PV modules is about 20 83 The average greenhouse transmittance of the film is 70 and of the insect proof net is 66 The transmittance parameters are derived from the measured data at the Yangpu PV Base in Hainan Province including factors such as material aging and accumulated dust as well as shadowing due to the framework As shown in Fig 2a in practical production PV systems are frequently interconnected on a large scale and there are mutual shading effects among different greenhouses To make the simulation model more consistent with reality the same greenhouse model is arranged at a distance of 4 m around the simulation model Fig 2b is an illustrative diagram of the completed model in the software PV module Insect proof net Translucent film h 2 h 1 b1 b2 b h Note b represents the span b1 represents the projection width of the south slope roof and b2 represents the projection width of the north slope roof h represents the height h1 represents the eave height and h2 represents the height from the crossbeam to the ridge of the roof is the angle of the south slope roof Same as below Fig 1 Parameters of the initial model a Multi span serrated photovoltaic greenhouse b 3D simulation model Fig 2 Photovoltaic greenhouse base 1 3 Comparison model setup Based on the initial model modifications are made to the design parameters to derive four sets of gradient models for multidimensional lateral comparisons 1 Model 1 for comparison Gradient model of span and longitudinal daylighting strip 2 Model 2 for comparison Gradient model of span and transverse daylighting strip 3 Model 3 for comparison Gradient model of span longitudinal daylighting strip and height 4 Model 4 for comparison Gradient model of roof angle and longitudinal daylighting strip 1 3 1 Model 1 for comparison Building on the initial model model 1 modifies two parameters the span and the width of the longitudinal daylighting strip When the vertical projection width of the south slope roof b1 remains constant at 4 5 m the increase or decrease of the span only acts on b2 To prevent PV module shading the span should be at least 6 m 31 in this latitude Due to greenhouse load restrictions the span should also not be too large Therefore the range of span variations in the model is set to be between 6 0 m and 9 0 m with a gradient of 0 5 m Generally four PV modules are connected in series to form a solar cell string which has a width of 2 3 m A 36 m long south facing slope roof can be fully covered by 15 5 sets of such PV modules In this scenario the width of the longitudinal daylighting strip denoted as cL is 0 m As the number of PV modules decreases the value of cL changes accordingly When the quantity drops to 14 sets cL measures 第 7 期刘 建等 基于Design Builder的锯齿型光伏温室光环境仿真与采光屋面优化213 0 292 m at 13 sets cL reaches 0 508 m