When you use a water filter, the pressure drop across the filter depends on several factors, including the type of filter, its design, the flow rate of water, and the properties of the water itself. The pressure drop is essentially the decrease in pressure as water passes through the filter.
In general, as water flows through a filter, it encounters resistance due to the filter medium, which can be made of materials like activated carbon, ceramic, or various membranes. This resistance to flow leads to a pressure drop. The pressure drop is typically measured in terms of the pressure difference between the inlet and outlet of the filter.
To determine the pressure drop in a specific filtration system, you would need to consider the characteristics of the filter, such as its porosity, surface area, and flow rate. These factors affect the resistance to flow and therefore contribute to the pressure drop. The manufacturer of the filter may provide information on the expected pressure drop or specifications related to the filter's performance.
Regarding the energy balance, it depends on the level of detail and accuracy required for your analysis. If you are interested in a comprehensive understanding of the filtration process, you could perform an energy balance to account for various energy inputs and outputs. This could involve considering the work done by the pump to overcome the pressure drop, any changes in potential or kinetic energy, and other factors influencing the overall energy consumption or efficiency of the system.
However, for many practical applications, a simplified analysis focusing solely on the pressure drop may be sufficient. In such cases, the pressure drop can be used as a practical measure of the filter's performance and the impact on the flow of water through the system.