Growing from flasks to flowering need quite a long time time, so it is always easier to buy adult or near adult sized orchids. There are many phals that can be flowered in sg, esp the star-shaped ones like bellina, amboinensis etc hybrids. It was thought that the Taiwanese hybrids need a cool temp drop for optimal flowering (on flower count and quality) but I find that many of them can still flower in the tropical lowlands, but maybe with less number of flowers.
As for cooled greenhouses there are a few Singaporeans who actually has a cooled greenshouse and one of them was featured in Straits Times a few mths ago. i grow a variety of South American cloud forest orchids in a 24hr cooled room. The other lowland tropical species were grown outside in the heat. And yes, like someone mentioned earlier in this thread, grow something that can flourish in our hot climate, I have some difficult maintaining the cool-intermediate growing species and hybrids in aircon even.