How To Measure the Output of Your Watermaker
1. Start up your system and leave the Sample/Tank valve switched to sample
2. Get a 500ml measuring cup
3. Put your phone into stopwatch mode
4. Time how long it takes to make 500ml of water
5. Put your phone into calculator mode. 1800 / number of seconds it took to make 500ml of water = litres of water produced per hour
We use a half litre, because it is easy and accurate. We are measuring how many half-litres of water we can make in a half-hour, which is the same as the number of litres we make in an hour. There are 3600 seconds in an hour, so that means there are 1800 seconds in a half-hour.
Common water production rates for our systems, with times to produce a half-litre of water:
35 lph = 52 seconds
70 lph = 26 seconds
80 lph = 22.5 seconds
160 lph = 11.25 seconds
240 lph = 7.5 seconds
Water temperature is a variable that will affect water production rates. Warmer seawater will produce fresh water more quickly. Nominal seawater temperature is 25 degrees.
If your system is producing water more quickly than it should, the most likely cause is low salt content in your source seawater. This is common when making water near river outflows and in inlets. It is best, for the long term health of your membrane element(s), to keep water production to no more than 15% more than the nominal output. Each 2.5 inch by 40 inch membrane has a nominal output of 80 litres per hour. This would mean lowering the system pressure so that the output of each membrane does not exceed 92 litres per hour.
2. Get a 500ml measuring cup
3. Put your phone into stopwatch mode
4. Time how long it takes to make 500ml of water
5. Put your phone into calculator mode. 1800 / number of seconds it took to make 500ml of water = litres of water produced per hour
We use a half litre, because it is easy and accurate. We are measuring how many half-litres of water we can make in a half-hour, which is the same as the number of litres we make in an hour. There are 3600 seconds in an hour, so that means there are 1800 seconds in a half-hour.
Common water production rates for our systems, with times to produce a half-litre of water:
35 lph = 52 seconds
70 lph = 26 seconds
80 lph = 22.5 seconds
160 lph = 11.25 seconds
240 lph = 7.5 seconds
Water temperature is a variable that will affect water production rates. Warmer seawater will produce fresh water more quickly. Nominal seawater temperature is 25 degrees.
If your system is producing water more quickly than it should, the most likely cause is low salt content in your source seawater. This is common when making water near river outflows and in inlets. It is best, for the long term health of your membrane element(s), to keep water production to no more than 15% more than the nominal output. Each 2.5 inch by 40 inch membrane has a nominal output of 80 litres per hour. This would mean lowering the system pressure so that the output of each membrane does not exceed 92 litres per hour.
