Constant pressure water supply system was explained and clarified in above paragraphs and this report has focused on demonstrating the effect of PLC and VFD control towards a high-level building. There are new changes built with this water supply system in order to easily and stably transport water to the residences and satisfy the needs. The water storage tank was constructed below the ground that makes the water flow straight ahead to the water network. The working process of pumps is controlled by the PLC referred to the pressure in the water network. A specific controller will be adopting which is the PID Controller, it has the advantage of simple implementation, and it detects and decrease error throughout a few actions, such as digitization the error proportion, break down remaining errors and adjust system constancy by forecast possible system actions.
The Constant pressure water system with VFD control brings tons of benefits to the residence in comparison of the old water supply system. There are six main benefits worth to mention as following:
Potential expansion with the system
Less demand in energy
Long usage life for equipment and only little maintenance is required
Water pressure is more smooth and steady
Architectural construction remains the same.
The capacity of a pump is the volume of water that it can pump per unit time.Capacity is also called flow rate. The symbol of capacity is Q or q. The capacity of a pump depends on its size and rotating speed. In practical, capacity is also relevant to pipe resistance and water pressure. It is expressed as cubic meters per second (m3/sec) in metric units or gallons per minutes (gpm) in English units.
The head of a pump is the energy acquired by a unit weight of water flowing through the pump. The symbol for head is H. The static head of a pump is the theoretical maximum height it can pump.
Head is expressed as meters. The head of a pump depends on the pump structure such as the diameter and rotating speed of the impeller and the curvature of the blades on the impeller. The head of a pump is usually measured through experimental methods.
The head of a pump includes suction head and discharge head. Suction head is the height between the inlet and the center line of the impeller. Discharge head is the height between the center line of the impeller and the outlet.