英语翻译Further design possibilitiesThere are many opportunities

英语翻译
Further design possibilities
There are many opportunities to further reduce either the need for ventilation,or the proportion of the year that it will be needed.Many of these present considerable technical difficulties but,if overcome,could significantly reduce the impact of subway systems on the environment.Opportunities exist in the development of noise control for tunnel ventilation fans,regenerative breaking,external resistor grids and platform edge doors (PED).PED in particular can result in a 75% reduction in station heat loads at the cost of a larger capital investment and increased maintenance.