# Default Condenser Loop Tower and Evaporative Fluid Cooler Design water flow rate

In CondenserLoopTowers.cc#L2435 and EvaporativeFluidCoolors.cc#L1332

```
// Design water flow rate is assumed to be 3 gpm per ton (SI equivalent 5.382E-8 m3/s per watt)
```

For this to be true, this assumes that a ton is a Ton of Refrigeration (TR), or 12,000 BTU/h.

But in general cooling towers capacities are given in terms of Ton of Heat Rejection (THR), which at 3 GPM/ton gives 15,000 BTU/h.

Indeed, at Standard rating condition, the deltaT is 10°R, which gives:

$$1 THR= 3 {GPM} * 8.33 BTU/gal * 60 s/min * 10 R =15,000 BTU/h = 4396.07 W$$

$$3 GPM = 0.000189271 m^3/s$$

$$0.000189271 / 4396.07 = 4.305E-08 m^3.s^-1.W^-1$$

Why is 5.382E-8 m3/s per watt used insead of 4.305E-8 m3/s per watt?

So this means I have to calculate the High Speed Standard Design Capacity, it means I should use the manufacturer's THR and multiply it by 12,000 BTU/h?

What am I missing?