Adding a heat recovery option to a dehumidifier can yield substantial energy and cost savings, provided the right approach is selected.

The two most common approaches to heat recovery are the glycol runaround loop method and the flat plate heat exchanger method. 

The former approach uses a coil placed in each air stream and connected by pipes filled with glycol, whereas the latter option is comprised of several heat plates with multiple channels through which liquid can flow. 

Though both approaches are commonly found within indoor pool applications, one is far better suited for these environments.

Take a deep dive into why PoolPak’s dehumidification veterans recommend the glycol runaround loop approach to heat recovery for indoor pools…


If the indoor pool is located in a cold climate, the heat recovery device will need to be built to withstand the potentially damaging effects of low temperatures. 

Flat plate heat exchangers frequently experience difficulties with draining away condensate, leading to a high risk that the condensate will freeze in the device. This requires that air be bypassed to prevent the plates from freezing, reducing its effectiveness when it is needed most.

When temperatures are below zero degrees Fahrenheit, the bypass is 20 minutes on/20 minutes off. 

However, with the glycol runaround loop approach, there is no risk of the condensate freezing and therefore no need to bypass air, making this a far more efficient approach for cold weather applications.

In these cold climate applications, a glycol runaround loop approach to heat recovery typically pays for itself after only one year.

Superior Corrosion Protection

The heat recovery device must not only be protected from the outdoor elements but the indoor elements as well. 

Flat plate heat exchangers are vulnerable to corrosion damage as they are typically not suitably coated for the indoor pool environment. This stands in contrast to glycol loops, which use natatorium-grade coated coils. With flat plate heat exchangers, there is an annual de-rate as the coil oxidizes and corrodes, but with the glycol approach, this is no longer a concern.

PoolPak coils are fully dipped for maximum corrosion protection.

Improved Heat Recovery Effectiveness

Plate heat exchangers force air down into different, complicated paths, creating a very high static pressure loss, requiring the use of more fan horsepower, which raises energy costs. However, the introduction of the glycol heat recovery coils into the existing air streams offers a substantially lower overall airside pressure drop, providing a lower operating cost and increased heat recovery effectiveness.

A More Compact Footprint

The glycol runaround loop offers all the above benefits in a much smaller footprint.

Plate heat recovery devices require special and complicated air paths within the unit, increasing the unit size and weight. With the glycol runaround loop approach, the heat recovery coil set fits directly onto the outdoor air and exhaust air openings already provided on the unit and does not increase the cabinet size. This is an important consideration on applications where roof loads are a concern.


Given that the glycol approach excels in several key areas, PoolPak’s dehumidification experts recommend it over the traditional flat plate heat exchanger for the indoor pool environment. 

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