Cooling water temperature rise
Cooling water temperature rise
(OP)
What is the normal temperature rise (Outlet water temp - inlet water temp)in air-to-water cooled machines ? I had always assumed it to be 2-3 deg C. But in one generator, it is around 6 deg C. Flow rate & pressure are normal as per name plate. Does this mean the coolers have insufficient capacity ?
* Basically, I would like a full-time job on part-time basis *





RE: Cooling water temperature rise
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Cooling water temperature rise
I am still keen to know what is the normal temp difference between outlet & inlet water. Any field experience or standards would help.
* Basically, I would like a full-time job on part-time basis *
RE: Cooling water temperature rise
The temperature rise will depend on the amount of heat losses and the water flow. For water,
1cal/1gr = 1°C rise
The guideline figures I have are:
AT 80 F incoming cooling water provide 0.85 GPM per each 1 kW loss for around 4.5° C water temperature rise.
The recommended water flow ratio increases or reduces with water temperature, 0.68 GPM for 70F; 1.15 GPM for 95F. However the water temperature rise is not constant if those ratios are followed.
RE: Cooling water temperature rise
RE: Cooling water temperature rise
flow (l/s)= 0.24 x losses (kW)/water rise
RE: Cooling water temperature rise
* Basically, I would like a full-time job on part-time basis *
RE: Cooling water temperature rise
In your example, the difference between designing for a 3º versus a 6º delta is essentially doubling the coolant flow. Therefore, while the unit might operate at a lower temperature, the pumping system is working twice as hard.
Different designers might well pick different design points, based on their unit's capabilities and liabilities.
TTFN
RE: Cooling water temperature rise
If the temperature rise is higher than similar transformers in your plant you may have more losses or a flow restriction.
This may also be an indication of circulating currents, harmonics, or a flux problem (possibly caused by harmonics).
If you circulation is temperature controlled you may have a bad sensor. You may also have thermometer errors.
Or, everything may be normal.
respectfully