Each year, March 22 is recognized by the United Nations as World Water Day. It’s a day to focus attention on the importance of water. This year’s theme is Nature for Water – exploring nature-based solutions to the water challenges we face in the 21st century. A similar theme Affiliated Engineers takes while planning, designing, and commissioning projects.
Building owners are increasingly interested in reducing their water use. Their concerns rest with uncertainty about the long-term availability of water supplies in combination with the knowledge that utility rates of water, stormwater collection, and wastewater treatment have increased significantly in the last few decades and are expected to do the same in the future.
Design professionals share those concerns and are looking to improve tools employing in their designs that will help reduce water use. Creating a project’s water balance (water accounting) is of great value in establishing ambitious, achievable goals for a project’s water use reduction and water reuse. This can be done in a conceptual way at the start of the design process and enhanced through detail and modeling advancing reliability as the design progresses.
As recognition of the value of water accounting to green design, in 2017 the USGBC introduced the LEED Pilot Credit: Whole Project Water Use Reduction. Also in 2017, the ASHRAE 191P Standard for the Efficient Use of Water in Building Mechanical Systems was released for public review. Among stipulations, the standard mandates that projects develop a water balance.
At Affiliated Engineers, we embrace this LEED innovation and standard as symbolic of the design industry’s direction. We identify the practice of generating building water balances as having the potential of transforming expectations and drastically reducing the volumes of water used in our buildings. Because Affiliated Engineers contributed to the development of both instruments, we know that much effort is needed by an alliance of design disciplines to take the next steps. Energy modelers have many diversity schedules to use, such as the ASHRAE handbooks, ASHRAE 90.1 reference guide, and the Labs21 schedules. Water modelers are at the start of the process of creating comparable references.
Some standard methodologies are in place to support water modeling. Much of it relies on careful benchmarking studies and on modeling tools that are ripe for enhancement. Benchmarks – whole building water use, plant materials water use needs, building occupancy and equipment schedules, and equipment specification information – can be used collectively to generate a reasonable approximation (statistically significant) of an hourly water profile. Today, many types of modeling are employed to create water balances. For example, wind speed correlation to align the data generated by using weather data to calculate evapotranspiration versus a typical meteorological year (TMY). A traditional energy model is leveraged to calculate the volume of water for reuse from cooling coil condensate. Many models are available to calculate irrigation water use. We expect that some of these will be aligned and integrated as the water modeling specialization advances.
Alignment of all these tools and their corresponding outputs is at the forefront of developing the water modeling field. Affiliated Engineers makes the best use of what is in place in our design work while using our experiences to reach towards sophistication on par with energy modeling. This challenge calls for creativity, determination and integrated design process. Specifically, we recognize that successful water modeling rests on the collaboration of mechanical, electrical, and plumbing/piping (MEP) engineering with the civil engineering, landscape design, and environmental engineering disciplines.
About the Author: Willa Kuh
Ms. Kuh is the Director of Planning at Affiliated Engineers, Inc. She is trained as an urban planner and has an expertise in resource management. At Affiliated Engineers, she is engaged both with building design and at the campus scale. In building design projects, she contributes to the high-performance design goal setting, analysis of site and design opportunity and preliminary design. Here, her understanding of water resource management from the perspective of an urban planner, civil engineer, MEP and landscape engineer make for outstanding integration of idea testing and analysis.
Contact Willa Kuh