please help me . I want to build a farm . and I selected S9 .
But i want a calculation . that if i want a bT . how much time is needed with one s9 ?
There is no difference revenue and power-consumption wise.
1 S9 will hash at 14 Th/s while having a power draw of 1375W
2 S9's will hash at 2 * 14 Th/s while having a power draw of 2 * 1375W
etc.
The only difference is that when you buy them in bulk, you might get bulk pricing, save on shipping and handling, maybe save some custom duties, buy more efficient cooling, racks,... It's more efficient to hire an electrician to review your wiring for 100 antminers, than hiring the same guy to look at your circuits for 5 antminers. It'll take roughly the same amount of time, but his hourly rate will be divided over 100 machines instead of 5.
For all other calculations, you need to tell us your electricity rate. Without this, there is no way to estimate your ROI.