Computer room precision air conditioning water system - hydraulic imbalance problems
1, the influence of hydraulic imbalance of cold and heat source unit to maintain the flow of cold and heat source unit within the limits of the prescribed by the unit to protect equipment from damage, the flow unit below design flow, the safety device will make the unit stop running.
When open when the stop will be lower than the output of unit provided by the indoor load the required power, at the same time, if the water suddenly decreases, and the controller too late reaction, also can not afford time to adjust the output of the unit, freeze is likely to occur in the water pipe, the consequences are serious.
If multiple units in parallel use, with the decrease of the load, unit capacity will be load capacity for design several times.
When actual operational units more than the actual need, part of the unit will be repeated opening and stop for a long time, and start-stop cycle is short.
In this way, will cause the unit efficiency lower and increase of energy consumption, and shorten the service life of the unit.
In order to ensure the good operation, reasonable approach is a setting on each unit balance valve, which can adjust the flow to the design value.
For parallel cooling tower installation, pipe outlet pipe should be set up on the balance, to ensure the balance of the cooling tower water.
2, the influence of hydraulic imbalance of the distribution system in the distribution system, the furthest distance pump loop by the its resistance differential pressure to a minimum, and away from the water pump recently loop has maximum differential pressure value.
If there is no any measures to make up the difference, so close to the pump or system loop small resistance of the loop, water flow will be much higher than the design discharge;
On the other hand, is much lower than design value, the whole system of the water in the uneven distribution of the state.
The uneven water can make the building room temperature uneven, and room temperature fluctuations;
Near the chiller room is too cold, distance of room temperature on the high side;
Another flow of large loop room relatively quickly achieved at room temperature, small flow loop room need to be a long time to reach the requirements of the room temperature.
Solve the hydraulic imbalance caused by different loop pressure difference of a good idea, is in the loop water balancing valve is set on manifold, to each loop flow to the design requirements.
3, a problem worthy of attention for variable flow system adopts two-way control valves, when some room room temperature is up to par value, the control valve opening will be down to reduce the output of the terminal device, however, as the control valve down, effect on the control valve differential pressure will increase.
So even if the valve to turn down again, but due to the differential further increase, traffic will be higher than the theoretical value, eventually may occur at low load operation of the valve will be turn on/off mode, generate oscillation phenomenon.
Due to total water cut in the system, also with the decrease of the pressure drop in the pipeline, making all the terminal device in the system pressure drop increases, the water pump working point along the water pump characteristic curve upward, pump head, make the control valve under close to the top lift the differential values, lead to valve failure and noise.
The solution is for (
Water pipe nipple a set since the function type differential pressure control valve, the system total water unchanged, the branch loop to keep a constant differential pressure value.