Is 涼台 not used anymore and does it differ from 陽台？ In Chinese literature there are four poems:

春林花多媚，春鳥意多哀；春風復多情，吹我羅裳開。 
朝登涼台上，夕宿蘭池裡。乘風采芙蓉，夜夜得蓮子。 
自從別歡來，何日不相思？常恐秋葉零，無復連條時。 
淵冰厚三尺，素雪覆千里。我心如松柏，君情復何似？ 


As you can see, the word 涼台 occurs. I used to live in a very hot country, so the idea of 涼台 seems much more natural than 陽台。But lately native speakers from both China and Taiwan tell me to use 陽台. Is 涼台 limited to ancient Chinese, or does it carry a different meaning?
Both 陽台 and 涼台 can be translated as 'veranda, balcony and deck' 

I suppose 陽台 refers to a deck you can sit on to enjoy sunshine, and 涼台 is a deck you sit on for cooling down. Which means the location of this deck determines how you call it.  

陽台 should locate in an area that is open and have access to plenty of sunshine. While 涼台 should locate in an area with shade. surrounded by tree, or near water. 

陽台 is a more common term because most people live in cities don't have a backyard to build a deck for cooling, but most apartment buildings do have balconies.