It’s been the kind of balmy summer in Washington, D.C. that makes Washingtonians thankful for air conditioning. Blasts of cool air offer a welcome greeting in homes, offices, and stores throughout the region. Unfortunately, the trek between those cool oases can be terrible, particularly when using public transportation. Though the stations, buses, and railcars of the Washington Metropolitan Area Transit Authority (WMATA) are equipped with air conditioning, maintaining an appropriate temperature has been a persistent problem.
In normal times, WMATA struggles to provide adequate air conditioning. In June, WMATA faced catastrophic failure in the chilled water plant that serves two stations (Dupont Circle and Farragut North). The chilled water plant in question consists of a chiller, a cooling tower, and air handling units to provide cool air in the stations. The chiller uses the refrigeration cycle to cool water that is distributed to the stations’ air handling unit and reject heat to the cooling tower. The cooling tower relies on evaporation to then reject heat to the atmosphere (the same principle that makes that bird go up and down). For WMATA, the water piping that connects the chiller to the cooling tower, known as the condenser loop, sprung a leak, rendering the system useless. Though it’s little solace to frustrated commuters, there are several emerging technologies that could have helped.
The technology improvements in buildings (and metro stations) is focused on energy. Because water is cheap, it is hard justify the expense of infrastructure to monitor it. As a result, monitoring water systems for water waste and inefficiencies is outside of the scope of most building management systems. In chilled water plants, sensors collect data on flow and temperature of water, but omit water management, such as leak detection. Seattle-based startup APANA offers a turnkey package of sensors, telemetry, and software that provide real-time monitoring of operational and mechanical water consumption. If such a system were installed in WMATA’s chiller plant, immediate notification could have been provided and downtime could have been minimized.
Another company, Aquanomix, offers a solution to collect data on water quality of chilled water plants. Though this technology would not have averted WMATA’s catastrophe, it would be beneficial nonetheless. As water evaporates in cooling towers, everything that is not water is left behind and concentrated over time as make-up water (and additional contamination) is added and evaporated. These contaminants reduce the efficiency of the chiller and cooling tower. The current method of treating them involves a water treatment technician taking physical measurements and adding appropriate chemicals to minimize impact on the system. Aquanomix uses sensors to provide real-time monitoring of water quality and integrates that information into the building management system to quantify the impact water quality has on energy efficiency.
Monitoring and management technology addressing water use in buildings has lagged behind the advances made in other building operations. The prolonged severe drought affecting the western United States has started to spark a conversation around innovation in water use. However, drought may not be necessary to justify investment in better technology for water management. In Washington, D.C. (which is having one of its wettest summers), better monitoring would have improved the environment of many commuters.
Tags: Building Innovations, Intelligent Building Management Systems, Water Conservation
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