AutomatedBuildings.com Article - Diving Into Building Water Management

Aside the global financial situation and its effect on construction most of the public, market focus, and attention regarding buildings is on energy; alternative energy sources, smart power grids, and energy use of HVAC and lighting systems in buildings. Somewhat lost in all that attention is water and specially water use in buildings. Water is a different resource. It may be our most precious resource. Where alternatives exist for energy sources the alternatives to water are none. If you don’t think water is a critical resource, consider that people can survive longer without food and certainly without energy than they can without water; that’s not surprising considering that two thirds of the human body by weight is composed of water.

Water also has a direct connection to energy use. Every gallon or liter of water used may require some pumping or treatment which uses energy. Reducing potable water uses reduces energy consumption.

Except for a few specialized building types (industrial processes with heavy water use, laboratories, etc.), the monitoring and management of water in buildings is generally pathetic. How many facility managers can monitor and manage real-time water use in their buildings from a personal computer? The answer is very few. This may be related to water having a lower profile than energy a large part is due to the dearth of innovative monitoring and management products in this sector. Surely some innovators, entrepreneurs and venture capitalists will eventually see the tremendous market potential for such water systems.

Overview
The critical nature of water is recognized in green building programs throughout the world. Water efficiency is one of the five main categories for US Green Building Council’s LEED certification. LEED credits related to water use include zeriscaped landscaping, water use reduction and innovative wastewater techniques. A major thrust of water efficiency is the reduction or elimination of the use of potable water. Techniques such as rainwater capture, advanced wastewater treatment, greywater “harvesting”, and water-conserving plumbing fixtures are all tools that can be used to reduce the use of potable water.

From a smart building perspective however, the interest is in how we manage and monitor the water use in buildings. More specifically, the focus is on the systems that will allow us to collect data on water use and provide actionable information to a facility or property manager. Monitoring and managing water use is really a part of the larger effort of the measurement and verification of a building’s performance. Management of a building’s water use can no longer be receiving a water bill at the end of the month from the water utility and comparing the bill to the previous month’s bill. It is a water management system that monitors and manages water usage that will change the process from simply supplying water to managing the demand for water.

Water use in commercial buildings obviously varies by building type, the type of plumbing fixtures, restrooms, landscaping needs, the use of hydronic cooling systems, kitchens, cafeterias, etc. USGBC offers some guidance on how to estimate a building’s water use. In new construction, water use is determined by estimated building occupancy; for existing buildings it’s past water use records. The baseline water use is calculated using building occupancy, a reduction of fixtures and fitting, and fixtures and fittings meeting or exceeding national or international plumbing codes and standards.

Control Systems
Think of a building as having two main water systems. One is the plumbing system within the building and the other is the irrigation system for the building’s landscape. Ironically, the monitoring and management capabilities of irrigation systems seem far beyond such systems for interior plumbing. The technology for irrigation has been honed from facilities such as golf courses and parks. Reducing the use of potable water for landscaping can be done by using recycled wastewater, captured rainwater and carefully selecting the plants and trees. Effective and efficient watering is left to the irrigation control systems.

Typically these are systems which may have a preset schedule and sensors which can adjust the watering schedule as needed. These sensors may be moisture sensors, flow sensors, rain shut-offs and “evapotranspiration” controllers (devices that measure the evaporation of water into the air and the lost of water by the plants, used in precisely calculating specific water need of the plants). The result is watering the right areas with the right amount of water and avoiding over or under watering and runoff.

The irrigation systems usually have a central controller connected to a system administration terminal. These central controllers have evolved from motorized valves to electromechanical clocks to microprocessor-based controllers. The connections between the controller and the devices are typically 2-wire proprietary connections. The administration systems will use maps of the landscaped areas (either developing those from a GPS or using the Landscape Architect’s CAD drawings) to identify the locations of sprinklers and sensors. Some irrigation systems are fairly sophisticated with the system controller able to download current weather predictions and adjust the system as needed. Products are also available for those organizations with a portfolio of real estate, allowing a central operation center to monitor each building’s system and
aggregate data for enterprise water use.

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Monitoring and management water systems in buildings have several advantages:

Networked water monitoring and management systems consist of water meters, sensor-operator water fixtures such as faucets, urinals, water closets, occupancy sensors, automated ball valves and water valves. Some of these devices can be monitored and managed and others can only be monitored. These types of management systems are also applicable to greywater, wastewater and recycled rainwater systems. For example a greywater system will need to monitor ultraviolet lamps used to disinfect greywater, filters, system pressure, UV lamp life and failure, pumps, etc.

As an example, the Sloan Valve Company, one of the few companies to manufacturer water management systems, has also used people counters in restrooms to determine traffic patterns and predict water usage patterns. At a major retail establishment they were able to use data on current water use and specific use of restrooms to correctly estimate water use and use of restrooms, including spikes and dips in usage around major holidays. The actual data, which was submitted as part of a LEED application, demonstrated an initial design underestimation of use.

Generally the area of water monitoring and management has been primarily developed around water utilities, landscaping applications and special water-intense processes and uses. The in-building systems mainly consist of metering and code-compliant restroom fixtures, and the industry has fallen behind in developing advanced hardware and software for in-building water management systems. It’s a huge market opportunity for someone or some company to seize and run with. (Please excuse the lame toilet pun!).

For more information about smart buildings, technology design or to schedule a Continuing Education program, email jsinopoli@smart-buildings.com

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