King County Aquatic Center

Background

The King County Aquatic Center is a large indoor facility that frequently hosts regional and national swimming events. The facility was originally constructed for the 1990 Goodwill Games. Over a number of years, the facility had been reducing energy use through operational scheduling changes. However, concerns over air quality at other large aquatics centers across the country led to close examination of the air exchanges being provided at the facility.

Measurements resulted in the realization that the facility was at times not capable of providing sufficient air exchanges to ensure healthy air quality. A significant percentage of the energy savings achieved since 2011 were the result of reduced air flow, and the air quality in the facility was being compromised. It was also determined that the facility’s peak airflow could not provide sufficient fresh air during large swimming events, which often bring thousands of people into the facility at one time.

The agency in charge of the pool decided it was necessary to add additional ventilation capacity for large events to increase air flow and improve indoor air quality. During project design, there was an intervention with planning staff to make sure that “fixing” the air quality issues would not come at the expense of energy efficiency. Management agreed that the design needed to incorporate energy efficiency. The refined design solution to the air quality problem was a comprehensive project to significantly improve air quality and upgrade equipment in the facility, while integrating the most efficient technologies available. During final project scoping, the project was also awarded a $500,000 energy efficiency grant (?) from the State of Washington. This money allowed for the replacement of boiler and heating system equipment that were not part of the initial scope of just addressing the air quality concerns.

Solutions

A prioritization process looked at the energy use and costs of different options for fixing the air quality concerns. The following measures were identified for implementation during the building retrofit:

New condensing boiler: 4,793 therms of savings
Heat recovery, natatorium: 529,925 kWh and 31,015 therms of savings
Removal of electric resistance heaters
Banquet hall HVAC: 34,332 kWh of savings
Locker room HVAC: 225,476 kWh of savings
Energy efficient lighting, including LED lighting for both interior and exterior applications: 132,529 kWh
Solar photovoltaic system: 100 kW

The Aquatic Center has a complicated mechanical system that makes use of condensing boilers, “PoolPak” dehumidification systems, and heat recovery. Designing the flow of air across the pool surface to minimize chloramines (chlorine byproducts) was a critical consideration during project design. It has been a challenge to properly balance the efficiency and performance of the different pieces of mechanical equipment while providing the healthiest swimming environment. The systems in the building are being continually examined to optimize performance, air quality and energy use. As of late 2015, the facility is undergoing phase two of lighting retrofit activity, which will replace the majority of the lighting throughout the facility with LED fixtures.

ANNUAL ENERGY USE

ANNUAL ENERGY COST

ANNUAL WATER USE

ANNUAL WATER COST

ANNUAL PLANT ELECTRICITY USE

ANNUAL PLANT ELECTRICITY COST

IN BUILDING ENERGY USE

IN BUILDING ENERGY COST

ACROSS NETWORK USE

ACROSS NETWORK COST

ANNUAL EMISSIONS

USE

COST

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KCAC Boilers

Large swim event at KCAC

King County Aquatic Center

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