Surface water
The third source of heat energy may be obtained from surface water, e.g. from a lake or pond near the pool. This surface water must be examined and approved for the water-to-refrigerant heat exchanger. Caution must be taken to ensure the heat exchanger is not damaged by organic materials that could clog the system.
A variation of this system uses closed-loop piping placed under the surface water to capture the heat beneath. Saltwater and coastal wells can be used if a secondary heat-exchange system is installed to prevent corrosion.
HVAC loops
Numerous applications that partner HVAC cooling tower systems with water-source heat pumps are now accepted as a viable source of renewable energy. The cooling towers are designed to ‘reject’ the heat extracted from the building with the air-conditioning system. These loops are typically connected to a gas boiler to supply heat to the building in the winter months. These types of heat sources are high-water pressure systems and require specialized plumbing accommodations.
Consideration should also be taken in low-temperature conditions as the equipment can freeze the heat exchanger and cause damage. This is why special equipment engineering must be part of the overall project development.
New, larger heat pump applications
Heat pumps were traditionally developed for residential and small commercial applications. In 2012, however, a larger commercial air source heat pump was designed and is now available in the marketplace. These larger units meet the needs of large pools at hotels, swim clubs, schools, and multi-family facilities. The heating capacity of these units, which are engineered for longer operating cycles, range from 35 to 145 kW.
Solar heating
Solar energy is an economical and environmentally friendly initiative to achieve sustainability. The efficiency of a solar system depends on how the sun reaches the panels. The solar panels are tilted to the latitude of the pool’s geographic region. Further, panels should have a southern exposure to allow them to absorb the most amount of energy from the sun and to achieve maximum solar efficiency.
During the day, water flowing through the solar panels collects heat and is redirected back to the pool. In the evening, however, the use of a pool cover is advised to prevent heat loss via evaporation. Studies show by simply covering the pool with a blanket at night can reduce heat loss by as much as 50 per cent.
An excellent technology combines solar energy with an air/water-source heat pump. This provides an alternative to gas, thus eliminating carbon emissions into the atmosphere.
Changes in heating technology will be ongoing as more consumers look for ways to reduce their energy costs. Other industries are offering variations of these heating methods to homeowners; it is only prudent the pool industry also take the initiative to study and become well versed in newer technologies.
As with all past articles, the author encourages comments from readers. Please send comments and/or suggestions with regards to what you have done to improve your knowledge on new heating methods as well as any experience you have had with respect to newer heating technologies, including geothermal and solar applications to ccentrella@keiseruniversity.edu.
Connie Sue Centrella is a professor and department chair for the online Aquatic Engineering Degree Program at Keiser University eCampus. She was honoured with the Evelyn C. Keiser Teaching Excellence Award ‘Instructor of Distinction’ and holds certification as a chief sustainability officer for the Team Horner Group. Centrella is an industry veteran with more than 40 years of experience in the aquatics field. She is also a former pool builder with extensive knowledge in pool construction, equipment installation, and manufacturing.
Excellent article on the movement of technologies for the pool industry. I am seeing more and more of my projects, looking to reduce their costs to operate, by modifying their existing heating systems like these are very successful.