Swimming pool heat exchangers transfer heat from a boiler, heat pump, solar, or geothermal source to pool water as part of a heating loop with the goal of maintaining a constant temperature in your Swimming Pool.
This article provides a brief overview of the benefits of stainless steel pool heat exchangers and other important practical design and application considerations.
Heat exchangers come in several varieties, such as shell-and-tube or plate-and-frame, and the heat transfer surface can be composed of different metals. Material choice comes down to cost, expected lifespan, pool water temperature and chemical composition, and availability. Stainless steel is a widely-available and accessible heat exchanger heat transfer surface material that is relatively durable, with high corrosion resistance. The optimal material choice varies by pool water and operating conditions, as well as financial constraints
Advantages of Stainless Steel or Titanium in Pool Environments
The most commonly cited advantage of stainless steel is its corrosion resistance — salt or chemicals in pools constantly interact with the heat transfer surface in a swimming pool heat exchanger, and all metals will suffer from pitting and deterioration to some degree. Outside of titanium stainless steel is the most stable widely available material choice, and at lower capital costs, it is suitable for all but the most saline or chlorinated pools.
Between Stainless Steel and Titanium, cupronickel heat exchangers are also widely used for s[as and swimming pools as they are corrosion-resistant to salt water
For plate type heat exchangers Stainless steel plates are stronger under thermal expansion and pressure fluctuations and have higher pressure ratings
New technologies now allow thinner plates which increases effective heat transfer.
Stainless steel is the balanced material choice for a swimming pool heat exchanger, with good heat transfer properties and average corrosion resistance – while Titanium is the ideal material choice if the budget allows.
Varieties of Stainless Steel
There are three main varieties of stainless steel for heat exchangers: SS 304, SS 316, and SS 316L. SS 304 is the most general-purpose varieties, that offers minimal corrosion resistance, but is unsuitable for high-chloride conditions. As SS 304 is the lowest cost material, it sees occasional use in clean freshwater heating systems. SS 316 uses around 3% molybdenum to significantly improve pitting and crevice carrion risk in chloride-rich environments. The “L” in SS 316L stands for low carbon; by using less carbon, which protects the material from corrosion at the intergranular level. This means that heat transfer surfaces will be slightly more corrosion-resistant in high-temperature applications, especially at the welds and seams.
Other Operating Considerations
Once you have selected a stainless steel swimming pool heat exchanger, there are a number of other considerations to keep the system running efficiently and ensure a long lifetime for your heat exchanger, including regular monitoring of water chemistry and routine maintenance.
Most pools are maintained at a pH of 7.2-7.8, and at chloride concentration levels of 1-3 ppm. High levels of chlorides from salt or chlorine as well as improper pH levels lead to faster deterioration of the stainless steel heat transfer surface through localized carrion and pitting. Proper management of water chemistry ensures long service life and consistently maintains optimal performance for your pool heat exchanger.
As with all heat exchangers, routine service and maintenance is key to maintaining desired performance and expanding lifespan. While maintenance differs by the pool system, generally care includes cleaning via flushing or mechanical cleaning to remove scale build-up as well as physical inspection. The presence of scale accelerations deterioration of the heat transfer surface, and inspections can reveal issues such as wear and stress fractures. Where possible, it is preferable to replace individual plates and chemically or mechanically clean the unit rather than total replacement. The investment into proper operation and regular maintenance allows the heat exchanger to last for many years, taking full advantage of all of the benefits of investing in stainless steel pool heat exchangers.
The first step in selecting the right heat exchangers for your pool or spa is selecting the right supplier with the expertise and product base to provide the optimal solution. Partnership with Valutech ensures access to a strong supply chain and a product lineup to suit the needs of virtually any application. This article is a brief introduction to stainless pool heat exchangers — for more information on available models, their features, and recommended maintenance practices, please contact Valutech here, or see the full pool heat exchanger lineup here.