Energy saving and solar electricity in fan-ventilated greenhouses
Energy saving and solar electricity in fan-ventilated greenhouses
复制标题
风扇通风温室的节能和太阳能发电
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
C. Paton
中科院分区：
文献类型：
--
作者：
P. Davies;A. Hossain;George Lychnos;C. Paton
温室栽培是一个能源密集型的过程，因此值得引入节能措施和替代能源。在这里，我们表明，有范围的节能风扇通风温室。作为风扇速度的函数的电力使用的测量已经进行了两个模型的1.25米直径的温室风扇，并与理论值进行比较。降低速度可以将每体积空气的能源消耗减少70%以上。为了最大限度地减少低速运行的资本成本，已经建造了一个冷却温室，其中风扇速度响应阳光，使得只有在中午左右才能达到全速。与恒速运行相比，节能约40%。从太阳能光伏模块的风扇的直接操作也是可行的，如从由无刷DC电机驱动的风扇的实验所示。通过比较不同系统在10年摊销期内的净现值成本（有和没有碳税来代表环境成本），我们发现，在所有关于税收和贴现率的假设下，阳光控制系统可以节省资金。然而，由于初始资本成本高，太阳能发电系统只有在非常低的折扣率下才有利可图。尽管如此，这一系统在主电源断断续续的发展中国家可能会因其可靠性而受到关注。我们建议温室风机制造商提高节能设计的可用性，如本文所述。
Greenhouse cultivation is an energy intensive process therefore it is worthwhile to introduce energy saving measures and alternative energy sources. Here we show that there is scope for energy saving in fan ventilated greenhouses. Measurements of electricity usage as a function of fan speed have been performed for two models of 1.25 m diameter greenhouse fans and compared to theoretical values. Reducing the speed can cut the energy usage per volume of air moved by more than 70%. To minimize the capital cost of low-speed operation, a cooled greenhouse has been built in which the fan speed responds to sunlight such that full speed is reached only around noon. The energy saving is about 40% compared to constant speed operation. Direct operation of fans from solar-photovoltaic modules is also viable as shown from experiments with a fan driven by a brushless DC motor. On comparing the Net Present Value costs of the different systems over a 10 year amortization period (with and without a carbon tax to represent environmental costs) we find that sunlight-controlled system saves money under all assumptions about taxation and discount rates. The solar-powered system, however, is only profitable for very low discount rates, due to the high initial capital costs. Nonetheless this system could be of interest for its reliability in developing countries where mains electricity is intermittent. We recommend that greenhouse fan manufacturers improve the availability of energy-saving designs such as those described here.