The science behind the solution
Simply put, hydronics means heating water. This concept is widely used in commercial buildings and residential homes. It allows for greater efficiency by using condensing boilers. The physics does not change just because the application is different.
The better the insulation, the less energy is required to heat the water. In an aquatic facility, one is heating an open container. The temperature of a large surface area eventually needs to meet a different temperature. So, the first variable to consider is: What is the desired pool temperature when compared to the existing air temperature? The second variable is: How fast should the body of water be heated? Does it need to go from 16 to 27 C (60 to 80 F) in an hour, or can it be done in 24 hours? Standard accepted practices are one degree per hour.
There were a few other requirements that had to be taken into consideration. First, the facility contained three separate bodies of water, each serving a different purpose. Due to local health regulations, it was mandatory to drain the spa every two weeks. This was an area of concern. They had to figure out where the spa would be drained, cleaned, or filled, and how the water temperature could be recovered within 24 hours.
To resolve this issue, Soukup and his team decided to go with a high-efficiency boiler solution. This system would use readily available Mod Con boilers. It would also be set up in a manner so it could heat different zones—bodies of water in this case. Each zone would have its own heating loads and set point requirements based on the application, desired temperature, and the volume of water needed in the pool.
The next step in the process was mathematical calculations. Keeping the bather load and required pool temperature in mind, the team figured out how they were going to transfer the heat from its source to the pools. They also gathered other necessary information—the total volume of water needed, surface area of the pools, and the ambient temperature of the facility.
Next was the variable information: What was the desired recovery time? What temperature would the water be maintained at and what was the desired temperature variance? This variance was the acceptable change from the set temperature. In this case, the pool needed to be 27 C (80 F), but they could allow a difference of 0.5 to one degree.
