秦岭国家植物园温室馆空调设计

结合秦岭国家植物园温室馆工程实例,介绍了热带雨林温室空调通风系统的设计方案,剖析了温室馆特点,以及针对热带植物生长环境需求应采取的温湿度控制等措施。     

大型玻璃温室通风降温系统形式探讨

随着国民经济的发展 ,大型玻璃温室应用越来越多。但是在我国不同地区 ,为保证室内温、湿度 ,所需要采用的方式及设计方案均不同。本文通过工程实例对大型玻璃温室通风降温系统形式进行了探讨。认为采用置换通风是一种效率比较高的通风方法 ,并阐述了效率高的原因 ;在降温过程中采用蒸发冷却技术是非常经济合理的方案     

上海植物园展览温室空调设计

简要介绍上海植物园展览温室的空调系统、通风系统和自控系统的设计，根据展览温室的特点，着重介绍为满足热带植物对环境的要求，而采取的通风、加湿、温度控制以及高大空间温度梯度的控制等方面的措施。     

上海植物园展览温室空调设计

简要介绍上海植物园展览温室的空调系统、通风系统和自控系统的设计,根据展览温室的特点,着重介绍为满足热带植物对环境的要求,而采取的通风、加湿、温度控制以及高大空间温度梯度的控制等方面的措施。     

降温技术在农业温室中的应用探讨

阐述了温室夏季的主要降温方法,主要有通风降温、遮阳降温、湿帘风机、高压喷雾等降温措施;对各个降温系统进行比较,提出各项系统的优缺点;最后,根据作者理解,对温室降温系统的发展趋势做出一些预测。     

现代温室温度环境控制综合节能技术

分析了传统温室温度环境控制技术存在的问题,结合自建现代温室实验平台,介绍了适用于温室温度环境控制的综合节能技术——地源热泵技术、太阳能通风技术及个性化温度调节技术。通过实验测试结果分析,论证了上述技术的节能效果。     

珠江三角洲现代温室环境与能耗水平调查与实测

对珠江三角洲的温室进行了调查和实测,主要目的是调查生产过程中现代温室的热湿环境情况和能耗水平,包括温室的热湿环境、全年运行时间、降温、升温以及其他温室设施的运行时间和温室的通风能耗、降温能耗、升温能耗等。调查与实测表明该地区温室环境基本满足所种植物的生长要求,但其控制能耗过高,将近达到30 kW.h/(m2.a)的电耗和4.5 kg/(m2.a)的煤耗。建议充分利用珠江三角洲的气候特点,大幅度降低能耗。     

上海地区温室供暖耗气量计算

本文详细分析了温室的热工过程,得出影响温室能耗的主要因素包括温室的太阳辐射、贯流放热量、通风换气放热量、室内土壤的地中导热量、室外气象、室内温度和作物的蒸腾作用等。通过能耗模拟软件计算了上海地区单层塑料膜温室在不同室内控制温度、不同供暖方式下的全年耗气量,结合实际调研得出,上海地区在种植常见瓜果类(番茄、黄瓜等)作物时塑料薄膜温室的全年累计耗气量约为5m3~7m3天然气/(m2温室·a)。     

基于云存储温室环境参数监测系统的设计

温室环境对农作物生长起着决定性作用,适宜的生长环境使得农作物的产量大幅提高,随着农业信息化进程的推进,农业数据量呈指数上涨的趋势。文章结合云存储和温室环境监测,提出了一个基于云存储的温室环境参数监测系统,详细阐述了系统的各个组成部分,用户通过该系统可以远程实时访问多个温室农作物生长发育情况,同时可以解决温室环境参数存储的问题,为用户进一步决断提供有力支持。     

基于ATmega8L智能农业温室大棚检测控制系统设计

本文设计了智能农业温室大棚检测控制系统。该系统基于AVR系列ATmega8L单片机为核心控制器,通过对农业温室大棚内各种环境传感器数据的检测及判断,实现对农作物的生长环境精准控制,极大程度摆脱了由于自然环境变化对农作物生长不利的影响,不仅提高了农业温室大棚生产的自动化程度,也提高了农业温室大棚的生产效率。     

Air temperature regime in a forced ventilated greenhouse with rose crop

The use of forced ventilation for greenhouse cooling and air humidity regulation purposes has been expanded around Mediterranean area. The aim of the present study was the experimental investigation of the variables, as well as their interaction, affecting the air temperature in a fan-ventilated greenhouse. On this purpose, measurements concerning both the greenhouse ventilation rate and climate variables inside and outside the greenhouse (air temperature and solar radiation inside and outside the greenhouse and outside wind speed and direction), were carried out in a multi-span fan-ventilated greenhouse. The greenhouse was cultivated with a rose crop and located near Karditsa, central Greece. The results showed that the difference between inside and outside air temperature was strongly related to the ventilation rate as well as to the incoming solar radiation. This finding allowed suggesting a simplified model of the greenhouse energy balance and finally an equation relating the greenhouse air temperature to the outside climate variables (air temperature, solar radiation and wind speed) and the greenhouse characteristics (cover transmission and ventilation rate). The calibration of the model gave satisfactory results and showed that it could be incorporated in algorithms used for greenhouse climate control and also that it could be used as a functional tool for more accurate estimations of ventilation needs.     

Model development and experimental validation of a floriculture greenhouse under natural ventilation

Greenhouse technology is an effective method of cultivation of flowers, crops, etc. under controlled environment. For any greenhouse, ventilation performance is a major factor in production, influencing the yield and quality of the products. Natural ventilation can be effectively used to maintain greenhouse microclimate, conducive to plant growth, when the ambient conditions are not extreme. The present paper discusses the modeling aspects of a floriculture greenhouse suitable for operation in typical Indian climate under natural ventilation. Combined ridge and sidewall ventilation is considered in the model. The model is validated against the test results of an experimental greenhouse. Parametric analysis is also done to understand the effects of variations in parameters such as wind speed, solar radiation intensity, effective greenhouse height etc. The study reveals that the performance of a greenhouse under natural ventilation is influenced considerably by parameters such as intensity of solar radiation, effective distance between the side and the roof vents, free wind speed etc.     

日光温室稳态温度场的数值模拟

根据质量、动量和能量守恒定律,利用对太原地区某自然通风日光温室温度场连续测试得到的相应数据,建立了该类自然通风日光温室的数学模型,应用新建数值模型,对自然通风日光温室内温度场的分布情况进行了稳态的模拟,结果表明：在稳态条件下,模拟值与现场测试数据有较高的吻合度,此模型可用于该类自然通风日光温室温度场的预测。     

Greenhouse microclimate and dehumidification effectiveness under different ventilator configurations

In this paper, the efficiency of two different greenhouse ventilation opening configurations on greenhouse microclimate during dehumidification process with simultaneously heating and ventilation was analysed by means of computational fluid dynamics (CFD) using a commercial program based on the finite volume method. The numerical model was firstly validated against experimental data collected in a tunnel greenhouse identical with the one used in simulations. A good qualitative and quantitative agreement was found between the numerical results and the experimental measurements. The results of the simulations performed for an outside wind direction perpendicular to the greenhouse axis show clearly the influence of ventilation opening configurations on the velocity, temperature and humidity distributions inside the greenhouse. With the first ventilation configuration (roll-up type) maximum air velocity inside the greenhouse was reached in the greenhouse near the ground, with the lowest values observed near the greenhouse roof. As a result, temperature and humidity decreased first near the ground and afterwards in the rest of the greenhouse volume during the dehumidification process. The exactly opposite pattern was observed with the second configuration (pivoting door type). The maximum air velocities were observed near the greenhouse roof where air temperature and humidity were decreased first during the dehumidification process. Energetically the first configuration is proven to be better since the ratio of latent to sensible exchanges during the dehumidification process was higher than the first configuration.     

Influence of Stabilizing Cables on Seismic Response of a Multispan Cable-Stayed Bridge

Abstract:   A recent trend in the design of long-span bridges is multispan cable-stayed bridges with three or more towers. A critical problem of multispan cable-stayed bridges is the stabilization of the central tower(s), which has resulted in increasing application of stabilizing cables. The Ting Kau Bridge in Hong Kong is one of a few multispan cable-stayed bridges adopting stabilizing cables ever built. In this article, the dynamic properties of multispan cable-stayed bridges with stabilizing cables and the effect of stabilizing cables on bridge seismic response are studied by referring to the Ting Kau Bridge. Based on a validated 3D finite-element model, modal analysis is conducted which shows that the longitudinal stabilizing cables bring about a number of global modes with strong modal interaction among the deck, towers, and cables. The seismic response and internal force in the central tower are found to be much larger than those in the side towers. The longitudinal stabilizing cables are very effective in reducing the internal force in the central tower generated by longitudinal earthquake excitation, but insignificantly affect the seismic response in the bridge deck and side towers. As a whole, the stabilizing cables act favorably in the reduction of seismic response of the bridge.     

Modeling and analysis of a fan–pad ventilated floricultural greenhouse

The application of greenhouse technology in the field of floriculture is rapidly expanding worldwide. In India solar radiation is abundant and the climate in the plains are rather hot and dry in summer months while the coastal parts witness a hot and humid climate. For greenhouses in such climates, cooling and ventilation are major factors influencing the production of quality flowers. In the present paper a thermal model of a greenhouse is presented based on fan–pad evaporative cooling. Thermal performance of the greenhouse, as predicted by the model under different climatic conditions is analyzed and compared with a reference study available in the literature. The analysis reveals that a suitable combination of evaporative cooling, shading and ventilation arrangements can effectively maintain the inside microclimate of the greenhouse within permissible limits throughout the year.     

Design and technology for greenhouse cooling in tropical and subtropical regions: A review

Greenhouse technology is a viable option for sustainable crop production in the regions of adverse climatic conditions. High summer temperature is a major setback for successful greenhouse crop production throughout year. The main intent of the paper is to present a comprehensive review on the design and technology for cooling of greenhouse during summer months. Effect of characteristic design parameters on greenhouse microclimate and the applicable cooling technologies have been discussed. A detailed survey of literature revealed that, apart from cooling, studies on greenhouse design, evaluation of new cladding materials for greenhouse covering and natural ventilation with respect to local climate and agronomic condition is necessary to achieve desirable benefits. Analysis of the earlier studies revealed that a naturally ventilated greenhouse with larger ventilation areas (15-30%), provided at the ridge and sides covered with insect-proof nets of 20-40 mesh size with covering material properties of NIR (near infrared radiation) reflection during the day and FIR (far infrared radiation) reflection during night is suitable for greenhouse production throughout year in tropical and subtropical regions. Based on the review, salient areas in need of further research are focused.     

Optimization of multispan plane Prager-structures with variable support locations

This study concerns the optimization of multispan Prager-structures whose support positions are unknown a priori and are to be chosen optimally. The intermediate supporting points are either those of simple supports or roller supports. Using calculus of variations, the necessary optimality conditions are derived which form the basis for the development of a general systematic procedure in determining the optimal layout of the multispan Prager-structures. An example is presented to illustrate the procedure.     

智能地热空调在花卉温室的应用研究

智能地热中央空调应用在花卉温室时,关键在于如何把供热与通风有效的结合,通过智能调节达到既保证室内温度,又保证室内湿度;通过自动换气还可降低二氧化碳的浓度,使温室内形成有利于花卉生长的环境,使花卉提前盛开,并保证花卉品质。大力发展农业设施与相应的农业工程,可实现高效农业生产的科学化,并提高农业研究的准确性,进而建立农业科技示范园,推动我国现代农业发展。