Hydraulic Balance Design Scheme
I.Description of hydraulic balance design scheme:
Static balancing valves are installed in the water supply and return pipelines at the thermal inlet of each unit. The specific scheme is made according to the plan of secondary pipe network drawn by field survey.
After the hydraulic balance debugging of ZhengFeng Valve Group is completed, each thermal unit can be guaranteed to reach the designed flow rate at the same time, so as to avoid the unevenness of heat and cold caused by over-current at the front end and under-current at the far end of the system.At the same time, do a good job in hydraulic balance calculation and debugging, replace the actual flow of too much circulation pump, frequency conversion pump to achieve greater energy saving space, system power consumption is also smaller.
According to the heating area of each unit, the design flow rate of each unit was calculated preliminarily according to the heat load index of 50W/m2 and the heat transfer temperature difference of 15 degrees (heat sink), and ZhengFeng software was applied to select the model according to the design flow rate.
II.Description of hydraulic calculation and balance design:
Since the balance valve is always related in the system and hydraulic conditions affect each other, it must be designed in accordance with a certain system method, which is the premise of comprehensive hydraulic calculation and efficient system debugging.The overall balance scheme generally follows the modular design method.The modular design method is shown in the figure below, which is simply to systematize the system into a tree structure and divide the system step by step. For example, in the figure below, a complex system is modularized with orange dots representing balancing valves.
In the following hydraulic calculation, as it involves a large number of parameters (pipe length, pipe diameter, flow rate, pipe roughness, local resistance coefficient, etc.), the calculation is often very cumbersome, and once the system design changes in the later stage, the calculation of the whole system is likely to need to be redone. Therefore, computer software is often used for hydraulic calculation. ZhengFeng Valve Group according to the principle of the above, combined with our decades experience gained by the hydraulic system design and debugging, will all engineering commonly used calculation parameters and is abundant of balance valve build database, and in the current HVAC industry based on the general balance debugging method, develop professional hydraulic balance testing instrument, can be easily accurately the implementation of the comprehensive hydraulic balance system.
1.Able to accurately measure its pressure drop, flow rate, temperature and data recording;
2.It has functions of balance, pre-setting, off and measurement;
3.Balance valve to ensure that the water system has the right resistance to obtain the required flow.
This balance scheme is applied to ensure that the water pump runs at the designed flow rate through ZhengFeng's perfect hydraulic balance debugging, so as to ensure that all the buildings and the entrance of each unit can reach the designed flow rate and avoid hydraulic imbalance of the water system. Complete commissioning, provide detailed commissioning report: valve model, position, design flow, actual flow, valve opening, valve pressure drop, design flow percentage, flow error within +10%.
For a system, hydraulic balance reveals the setting point of the variable frequency pump. After the balanced debugging of the system, all the additional pressure drop is added to the main cooperation valve. At this time, the main cooperation valve is fully opened to reduce the pump frequency to the system to obtain the design flow rate. At this time, the pump head is the head really needed by the system, and the frequency conversion should be based on this.In this way, the safest and best energy saving effect can be achieved.