In India, railways still continue to be the most prominent means of transport, especially non-air conditioned railway that carries around 3.5 billion people every year. Thermal comfort in these non-air-conditioned trains is predominantly influenced by windows and fans. The present study orients around the effect of fan air as well as naturally ventilated air on thermal comfort of passengers. The study is part of a field survey followed by an experimental investigation that was carried out in non-air-conditioned railway coaches during summer afternoon, with more than 1500 subjects of different gender and age category. The study significantly contributes in defining an elevated acceptable range of comfort air velocity inside a moving stock. The mean threshold air velocity where passengers responded a neutral PCV (passengers' comfort vote) is found to be 2 m/s which is much higher than conventional standards for enclosed static buildings and premises. The clear dominance of behavioral adaptation has been noticed in expression of thermal comfort by the passengers. This strengthens the idea of adopting some alternative method to deal with thermal discomfort of non–air-conditioned railway passengers. Here a novel term as ‘zone of independence’ (ZoI) has been defined at which the effect of air velocity becomes independent on passengers' comfort vote. This ZoI can significantly be utilized while optimization of thermal comfort in an ICF railway coach.

中文翻译：

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印度干热气候下自然通风铁路客车空气流速和相对湿度对乘客热舒适性的影响

在印度，铁路仍然是最主要的交通方式，尤其是每年运载约 35 亿人次的非空调铁路。这些非空调列车的热舒适度主要受窗户和风扇的影响。本研究主要围绕风扇空气以及自然通风空气对乘客热舒适度的影响。这项研究是夏季下午在非空调铁路客车上进行的一项实地调查的一部分，随后对 1500 多名不同性别和年龄组的受试者进行了实验调查。该研究对于确定移动车辆内舒适空气流速的可接受范围有很大贡献。乘客做出中性 PCV（乘客舒适度投票）反应的平均阈值空气速度为 2 m/s，远高于封闭静态建筑和场所的传统标准。在乘客的热舒适度表达中，行为适应的明显主导地位已被注意到。这强化了采用某种替代方法来解决非空调铁路乘客热不适的想法。这里定义了一个新术语“独立区”（ZoI），在该术语中，空气速度的影响变得独立于乘客的舒适度投票。在优化 ICF 铁路客车的热舒适性时，可以显着利用该 ZoI。