When it comes time to select a new natatorium dehumidifier, there are many factors to consider. Some of these key considerations include: dehumidifier life expectancy, serviceability, cost to maintain, growing maintenance costs as the unit ages, ease of use and energy usage. Energy usage is one of the key items that define the cost of running your indoor pool.
Will the dehumidifier you choose do all the dehumidification it can with outside air before it turns to the expense of running its compressors? Will it recover energy from the air it exhausts in the most efficient manner possible (or use an inefficient glycol loop for recovery)?
Or will it dump the waste heat generated by the mechanical dehumidification into pool water to show a false level of efficiency (since running compressors to heat pool water is inefficient)?
An efficient pool dehumidifier should be recovering energy in all modes of operation. It needs to recover energy when it is exhausting air and when it is providing mechanical dehumidification.
The simplest energy recovery devices are passive devices. A passive device does not require pumps or motors. The ability to clean the energy recovery device is a key aspect of maintaining its performance. An energy recovery device that has been plugged with salt deposits from pool chemicals that have mixed with the air and then condensed out of the exhaust air within the heat exchanger, will not work. Air to air flat plate heat exchangers and energy wheels are both very bad choices for indoor pool applications. They are both very difficult to clean.
The good news is that there is one passive device that is very efficient and that can be easily cleaned. That device is the refrigerant based heat pipe. These devices are narrow enough to allow coil cleaning chemicals to flow through the device and remove any built up deposits without plugging the device’s fins. A yearly washing of the heat pipe is all that is needed to keep it operational for years.
A well-designed pool dehumidifier will also take advantage of the energy recovery properties of the heat pipe when the unit is mechanically dehumidifying. The heat pipe can be configured to pre-cool air coming into the cooling coil, and then the heat removed in the pre cooling process can be passively transferred back into the cooled dehumidified air that exits from the cooling coil. This makes the dehumidifier much more efficient and reduces the tonnage of compressors required to dehumidify the natatorium.
Finding a dehumidifier that uses a heat pipe and uses the heat pipe to its maximum benefit is one of the keys to running an energy efficient natatorium. The heat pipe is such a simple and efficient energy recovery device that it will save big energy and maintenance dollars for years to come.
Rich Meyer is an engineer with Efficient Air Systems, Inc., and can be reached at firstname.lastname@example.org or efficientairsys.com.
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