Ventilation energy
An indoor pool’s second-largest energy user is ventilation equipment. Power use can, however, be reduced, primarily by using a dehumidification unit to condition and control the pool space. These units are designed using a specialized refrigeration cycle that switches between heating and air conditioning modes based on outdoor conditions. In addition, these units can use exhaust air to pre-heat or pre-cool outside ventilation air. The dehumidification cycle may also redirect heat from the compressor to heat pool make-up water, re-circulated pool water and domestic water. These systems are complex, but a basic understanding of the energy conservation features can be used for maximum benefit.
One recent industry trend to maximize efficiency is to incorporate a geothermal system, which transfers heat from the ground into the dehumidification system. According to a recent project at Morehead State University in Morehead, Ken., use of geothermal systems save on both initial installation and long-term operating costs. However, this option should only be considered in geographic locations with the ability to accommodate a geothermal well field.
Another efficiency maximization technique is temperature and humidity control at night or during unoccupied times. An operator should consider, for example, using a night setback temperature and relative humidity level, which reduces the evaporation rate and energy load on the ventilation system. The dehumidification unit, however, must remain on at all times to control moisture in the pool space. Turning the system off as an energy-saving solution can have adverse effects. A shut-down system can lead to high temperatures and high relative humidity, which will begin to migrate to other areas of the building and attack its structural system, resulting in significant problems.
Auxiliary devices
Aside from primary control procedures for evaporation and ventilation, other strategies, which focus on pool facility operations, can also reduce energy consumption. These strategies involve auxiliary devices, such as circulation systems, lighting, filters and pool water heating.
Variable-speed pumps
The use of variable-speed pumps on circulation systems and play features has increased dramatically in recent years. These pumps can operate at different speeds to deliver water flow according to the operator’s needs. Operating at slower speeds reduces power consumption, energy costs and noise, all while extending the life of the equipment. The pumps are monitored by a variable-frequency drive (VFD), which controls the motor to match flow settings. Flow rates can be adjusted based on use, e.g. daily circulation, backwashing, play features, waterfalls, water slides or lazy rivers, providing flexibility and reducing energy costs. A significant number of pool pump manufacturers are now providing variable-speed pumps in their product lines as standard equipment.
