AUTOMATED WATER MANAGEMENT IN BUILDINGS WITH 3-PHASE PUMPS

Most commercial buildings, large villas, residential buildings and high rises typically use a water management system that is powered by a 3-phase pump or event typically a bank of such pumps.  Typically, these pumps are used to transfer water from a ground or below-ground level tank to one or more overhead tank and they are connected to a pump panel for managing this system. There is inevitably both wastage of water and energy in this process when it is managed manually and often even dedicated manual labor to manage the process.  The water overflow from tanks or the overworking of the pump are typical causes of such wastage. If a pump runs dry then there is a reduction of pump life as well. An automated water management system, which can be independent or part of the Building Management System (BMS) can serve to eliminate this wastage, by efficiently managing the pumping of water.

There are many different layouts for these systems based on the size of buildings or the layout of the buildings and the water tanks. Most commonly, one overhead tank is on the top of the building, and it is supplied by one underground tank under the building. But, in the case of high-rises there may be many service levels where tanks hold the water before another pump transfers them to the next service level water tank and so forth in stages all the way to the top of the building. Situations are also possible for large buildings with many wings, where multiple overhead tanks exist in a single building, being supplied from a single ground level tank, via a single pump or multiple 3-phase pumps. In a commercial complex or a multi-apartment residential complex the same single ground tank and multiple pump(s) may supply multiple overhead tanks that sit on the top of different buildings. So, the layout of the water supply system can be highly varied depending on the circumstance.

In most cases, irrespective of these varied layouts the water management is done manually, which means that some indicator is used to determine the water level in both the sending tank and the receiving tank, which is used to manually turn the Pump, on or off. In many cases this involves manual monitoring of the tanks, visually or through some outside indicators. The pumps are usually manually turned on or off from the pump panel, by someone tending to them, who uses the tank level indicators to make that decision. Some pumps also have an ‘automated control’ option on their panel, besides the manual control. This option allows an external controller to signal them to be turned ON/OFF. When the manual option is not used, an external controller, typically a Direct Digital Controller (DDC) would have to be used to perform this automated control activity. Such a DDC would have to be fed with information from sensors about the water level from various tanks and would use that information to control the pump(s), by using its connection to the pump panel.

So typically, this system entails the following:

  • 2 Digital Water level (float) sensors for the lower tank(s) – one triggers by min level and the other by max level
  • 2 Digital Water level (float) sensors for the upper tank(s)­– one triggers by min level and the other by max level
  • A Direct Digital Controller (DDC) that connects to the 3-phase Pump Panel and to these sensors

This is a wired system where a twisted pair connects the DDC with the various sensors. The distance that can be covered is almost 300m between the sensors and the DDC, which would effectively address even most high-rise deployments.

The DDC logic is automated to operate as follows,

  • If the upper tank has water at or below its min level, while the lower thank has water above its min level, the DDC will operate the pump ON
  • If the upper tank has water at or above its max level, then the DDC will operate the pump to be OFF
  • If the lower tank has water below its min level then the DDC will operate the pump to be OFF irrespective of the situation of the upper tank.
  • If the setting on the pump is set to Manual, then the DDC cuts off the automated operation of the pump, but still displays both the water tank levels

BuildTrack offers such a water management system consisting of a DDC and sensor that can connect to most existing pump panels. A DDC can also be accessed via Smart App remotely to control and monitor the water level. Read more about this in our upcoming blog on automated water management system.

 

Diagram of water management system for 3-phase pumps

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