Alternative Energy Sources Help Improve Efficiency
Increasing energy efficiency remains the No. 1 way in which recreation industry professionals are trying to reduce their operating costs.
In fact, "According to the U.S. Energy Information Administration, an estimated 41 percent of total U.S. energy consumption in 2014 was consumed in residential and commercial buildings, so increasing the energy efficiency of the built environment will have a tremendous impact on the overall energy consumption of our nation," said Robert McDonald, senior principal, NCARB, LEED AP, Ohlson Lavoie Collaborative (OLC), an architectural firm based in Denver.
"Recreation and wellness centers especially consume vast amounts of energy," McDonald said, "largely due to their operating hours, large-volume spaces, physical activity levels, levels of comfort expectations and aquatic features."
There are some effective ways, though, to improve operating efficiencies and reduce energy costs at recreation facilities, one of which is to use regenerative media filters in the aquatic sanitation system.
"Regenerative media filters (RMFs) are the latest technological advance in replacing sand media filter technology," McDonald said. "Sand filters require a frequent backwash cycle in order to cleanse contaminants from the sand media, and every backwash cycle is literally sending money and resources down the drain, because water that has already been heated and treated is used during the backwash cycle."
RMFs have a reduced backwash cycle, which cuts down on the amount of wasted pool water and saves the heating and chemicals related to treating replacement water. For instance, RMFs would save a typical indoor leisure pool with a 2,000 GPM recirculation rate about 2.2 million gallons of water per year.
"This not only improves the operating efficiencies of the facility, but it also reduces the impact on a town's water and wastewater treatment systems, and reduces sewer and water costs," McDonald said.
In addition, water and electricity-efficient laundry appliances can reduce electricity and natural gas bills, as well as reduce water and chemical use. High-efficiency units today clean and dry at faster rates, while reducing staff wait time as well.
Besides that, installing water-reducing plumbing fixtures can save on not only your water bill, but on heating bills as well. Water-reducing shower heads, automatic faucets and automatic flush valves should be considered as part of the energy-efficiency equation, too.
Solar panels, as an alternative energy source, also can be used on a recreation and wellness center, noted Sam Elsheikh, OLC's chief financial officer, AIA, NCARB, LEED AP, and director of OLC's Orlando, Fla., office.
"Our life-cycle analyses have shown that the best use of solar panels on an aquatic center is to use a solar hot water system to preheat the pool and domestic hot water systems. Our studies have shown that there is an average 10-year payback on the installation of these alternative systems," Elsheikh said.
Daylight, another benefit that can be reaped from the sun, can be used to supplement the operations of a facility and make them more energy-efficient. "Placing windows and skylights in strategic locations, and the use of light transfer tubes will reduce the reliance upon artificial light sources during the day, which will save energy," he said.
Similarly, Jack Patton, AIA, LEED AP, principal, RDG Planning & Design, Des Moines, Iowa, suggested using sunlight and harvesting natural daylight to illuminate appropriate portions of a facility.
"This can be achieved via direct illumination (sun coming through a window), reflected sunlight (light shelves), dispersed light (skylights, light monitors, semi-transparent walls, borrowed light systems) and more," Patton said. "The travel path of the sun is well known, and our ability as designers to harvest that energy (light) is profoundly important in boosting the energy efficiency of buildings we design."
He also advised using reclaimed water resources.
"A few great questions to pose to yourself on this topic are 'What happens at your facility when it rains?' and 'Where does the rain go?'" he said.
Some of the most energy-efficient facility operators and managers, he noted, harvest the rainwater that hits their facility to do many things, such as water the landscape; flush toilets and urinals, and be used in other graywater systems; offset potable water demands across the board; become part of a building's cooling system; reduce or eliminate the stormwater burden for a campus, municipality or district; and even become an artistic element of a building design.
For any swimming pool, the most effective means of reducing use of resources is through thermal blankets (pool covers). More than 90 percent of heat loss, chemical use and non-backwash water loss occurs at water surface level.
"By creating a barrier between the water and the atmosphere these losses simply stop occurring," explained Justin Caron, principal, Aquatic Design Group, Carlsbad, Calif.
"On an indoor pool, having a pool cover on the pool will allow the HVAC/dehumidification system to ramp down, saving a significant amount of electricity," he said. "There are downsides (mainly labor, safety and storage), but many energy codes mandate their use now because they are so effective."
When it comes to designing a facility for energy efficiency, it's a good idea to break down the building's energy consumption into three basic categories of need: thermal comfort, power and lighting.
"The definition of thermal comfort in a building is fairly straightforward; this is the human need for protection from outdoor temperatures that are above or below body temperature," McDonald said. "Power needs can be from appliances, equipment in the building, or for personal devices such as computers or other electronics. Lighting is obviously needed so that the inhabitants of the building can see what they are doing or what is going on around them."
The thermal comfort of a space depends largely upon the function of heating, ventilation and air conditioning (HVAC) systems as well as the integrity of the building envelope.
"There are also considerations of thermal mass and its impact on temperature swings that must be kept in mind," McDonald said. "The school of thought developed over the past 30 years or so has been that an HVAC system that is right-sized for the spaces it is serving (not too small to keep up nor too large to be overkill), combined with a tightly sealed and highly insulated exterior envelope will yield the best overall energy performance."
HVAC systems can be traditional mechanical systems, such as the packaged air conditioning unit typically supplemented by variable-air-volume boxes for final tempering. "These units typically operate on electricity and natural gas, and their efficiencies continue to get better and better as technology develops," McDonald said.
"However, more and more research and testing is being done to see how passive and active solar heating, passive and active natural ventilation, geothermal and other systems can be developed into a good solution for recreation and wellness facilities," he said. "The state-of-the-art recreation center of today will incorporate a full building automation system (BAS), which senses and controls all of the heating, cooling and dehumidification throughout the building."
Particular challenges associated with maintaining thermal comfort in a recreation and wellness center include spaces that want to remain fairly constant in temperature and humidity, and others that must be able to change and adapt to a different use several times a day.
For example, an indoor pool environment will be most affected by the water temperature, which is ideally constant. "The HVAC system, therefore, has a simple assignment: Maintain the air at 2 degrees Fahrenheit above the water temperature and the relative humidity at 55 percent," McDonald said.
"It may take a lot of energy to do this, but it is not necessarily complicated from a controls point-of-view. On the other hand, the environment in a fitness space, gym or group exercise room will depend upon the amount and type of physical activity taking place," he added. "Depending upon how many people are exercising, and if it is a high-intensity activity, like an aerobics or group cycling class, or a low-intensity activity such as yoga, the HVAC system will have to perform very differently and change its operating protocols very rapidly."
Elsheikh noted that using fans is a good way to design for efficiency as well.
"Our bodies sweat to keep cool, so one thing we can do as designers is to help make this built-in system more effective in our buildings," he said. "The simple presence of moving air can be a powerful ally in a recreation and wellness center. As air moves across our skin, the evaporation effect reduces the temperature and keeps us cool, so including air-moving equipment, such as a fan, is important to consider in the energy consumption analysis."
The air in a high-volume space—such as a gymnasium, natatorium or fitness floor—quickly can become stratified without adequate circulation. High-volume, low-speed ceiling fans will help to circulate the air within a space, improving user comfort, as well as reducing the amount of air that an HVAC system is required to circulate.
McDonald also noted that having video monitors mounted on the walls or suspended from the ceiling may actually increase the amount of electricity that a fitness floor consumes over individual entertainment systems. However, neither one of them is as relevant to overall energy consumption as the lazy river circulation pump in the pool mechanical room.
Pumps in the pool mechanical room need to be sized correctly and should always include a variable frequency drive (VFD).
"Pumps consume the majority of their energy at the moment they start, resulting in a large 'peak' demand all at once, when the system is first turned on," McDonald explained. "These high peak demands use a lot of energy and result in increased usage charges from the utility company. Installing a VFD on the pump allows a 'soft start' on the motor, evening out the energy demand at startup as well as automatically adjusting the motor to run at exactly the right speed to move only the water it needs to. These can also be monitored and controlled by the BAS system."
Lighting consumes a significant amount of electricity in a recreation and wellness center, too, and in buildings in general. Energy codes now are dictating that light fixture energy consumption in new construction be limited to a maximum of watts per square foot, typically in the 2 w/sf range.
"This can be very challenging for an illumination engineer, to design a lighting system that not only provides adequate illumination but also fits under the code allowance, but it is possible," McDonald said. "The development of LED technology and its adaptation to building lighting has made this much easier, because LED fixtures use at least 75 percent less energy and can last 25 times longer than traditional incandescent lighting (U.S. Department of Energy). Perhaps the single most effective energy-efficient design tool at hand is to specify only LED light fixtures for your project."
And, perhaps the ultimate source of free energy is the sun.
"Care has to be taken not to allow glare (or direct sunlight) to disrupt the function of a space, but placing windows, clerestory and skylights in strategic locations will not only make a building feel better to be in, it will also save energy," Elsheikh said.
Translucent panels, which are better at insulating than glass, also can be used to allow light to come in, all while reducing glare and improving the insulating value of a wall or roof over glass products.
"Light wells, light shelves, light 'chimneys' or tubes, and other concepts, are used to get daylight into occupied spaces that are located deep within the building," he continued. "Using these, combined with occupancy sensors that turn lights on or off when people enter or exit the room, and with daylight sensors that actually dim the lights when the daylight is coming in, daylighting can be an effective strategy to reduce energy consumption and improve the overall experience of a design."
Caron said almost any modern design will incorporate energy-efficient measures due to mandates by modern codes.
"Going the next step to saving significant dollars and reducing [a] carbon footprint is often the result of a life-cycle cost analysis in which the capital costs are weighed versus the savings offered," Caron said. "In some cases there simply isn't sufficient money available on the front end to implement higher efficiency systems."
High-efficiency heaters and thermal solar systems are the two most common solutions for reducing natural gas use (the most common means of heating pools).
For electricity, LED lights and variable frequency drives are the two most common solutions for reducing electric use in the pool. Modern chemistry controllers and diligence with regard to maintaining water quality are the two most common means of reducing chemical use. And, for water and sewer, pool covers and regenerative filters are the two most common means of reducing water use. Maintaining water quality is the single most important way to do so.
"In any building design effort we are continually faced with multiple scenarios and strategies about how to solve a given problem, and it is how we react to these scenarios that often governs the overall energy efficiency of a sports building," Patton said.
In broad categories, he said it is wise to focus on the following primary categories of impact:
- Sustainable site planning: Orient your facility to optimize the use of natural and sustainable resources afforded in your location. Use a local water resource (like a pond) for extracting heat from a heat pump, or irrigating specialty plant materials, etc.
- Energy use: For high efficiency, use the most efficient equipment you can obtain. "Be efficient in both the initial purchase (as an analogy, buy a fuel-efficient car) and in ongoing operation of your facility (as an analogy, drive with fuel efficiently in mind). Be conscious of all your decisions, now and in the future."
Improving Efficiency in Existing Buildings
A facility owner can do many things to improve energy efficiency of an existing building.
"Some of these are fairly simple to implement, others, perhaps, not so much," McDonald said. "Perhaps the single most effective energy-efficiency measure at hand is to change all of the light fixtures or light bulbs in your facility to LED technology."
LED lights are cool to the touch, which means there is more energy being directed toward producing light and less energy being wasted as heat.
"They use 75 percent less energy than incandescent, and 18 percent less than compact fluorescent light sources (CFLs), while also lasting 25 times longer than incandescent and 15 times longer than the equivalent CFL bulb," he said. "This project will give you a '1+1=3' effect because not only will you save on lighting costs, but also on cooling costs and operating costs to replace burned out bulbs."
Similar to a typical home, most heating and cooling escapes a commercial building through openings—windows and doors. But, by installing a second set of doors to create a vestibule, or making a vestibule longer so that the outside doors have a chance to close before the inside doors are activated, that will help keep conditioned air inside.
Caron also noted that any existing building can be renovated to reduce the energy use.
"The means can be as simple as installing (and using) pool covers, or as involved as replacing existing mechanical and chemical systems," Caron said.
Patton suggested the first step is to assess the quality and thermal performance of your existing facility. You have to measure it to know it.
The following strategies, he said, play important parts in improving the energy efficiency of existing facilities: building envelope analysis, equipment efficiencies (and upgrading older equipment), measurement and verification, solar shading and orientation corrections, operations efficiencies, strategies and training, commissioning and re-commissioning.
Some facilities have achieved various levels of energy efficiency.
For example, the University of Oregon Student Recreation Center Expansion and Renovation is a highly efficient facility. Patton said the facility uses natural light in an efficient manner, uses rainwater for graywater needs (toilets, urinals, etc.), captures energy from the sun and converts it to electric power via photovoltaic panels on the roof, reclaims waste heat from campus steam tunnels to partially heat the building and pool systems (nearly a free resource), and uses high-efficiency HVAC systems and strategies to create a high-performance building.
In another example, Good Shepherd Medical Center directed OLC to follow the principles of sustainable design in the creation of a 75,000-square-foot wellness center constructed on the new Hawkins Road Campus in Northeast Longview, Texas. Certification of sustainable design measures was sought under the LEED (Leadership in Energy and Environmental Design) program administered on a national basis by the American Green Building Council.
And, such measures were delivered under five broad categories of sustainability as they apply to design construction and operations: site, energy, water, products and air quality.
The benefits from each category include savings in long-term operational expenses, reduced consumption of energy and natural resources, increased consumption of recycled or renewable resources, reduced landfill volumes, and many improved environmental health factors.
For example, water conservation measures included dual-flush toilets, low-flow urinals, water-saving shower heads and automatic fixtures.
Building energy systems for heating, cooling, ventilation, power and lighting were designed to save up to 20 percent over conventionally designed buildings. A variety of design and engineering measures included: superior building insulation, high-efficiency light fixtures, energy recovery systems, special energy-saving glass, a solar-powered heating system to supplement conventional fuel sources for heating indoor pools, and more.
In another case, the student recreation center at the University of Colorado Boulder has improved energy efficiency, Caron noted.
The original student recreation center included several dated bodies of water that were not code-compliant and did not provide the experiences that today's students expect.
The job of ADG, together with Davis Partnership and Cannon Design, was to rehab the existing diving well and lap pool in the student recreation center and create a new outdoor experience that could service lap swimmers, casual swimmers, loungers and students who just wanted a place to play in the water outdoors.
And, "as part of a LEED Platinum project selecting the most efficient and energy-friendly equipment was imperative to the success of the overall project. In addition to the complete rehabilitation of the two existing pools with new automatic and high efficiency equipment, a new outdoor pool was added that closely matches 'Ralphie,' the school mascot," Caron said.
"The pool is heated with reject heat from the ice rink located within the student recreation center," he said, "which allows the pool to be operated without any natural gas."