October 18, 2016
By Ralph Kittler
Imagine the following scenario: an aquatic facility manager is vacationing with their family in Europe and suddenly receives an e-mail alert on his/her smartphone regarding a problem with the indoor air quality at the commercial pool he/she manages. Unfortunately, the on-duty maintenance staffers are not able to diagnose or respond, but the problem needs to be fixed immediately. Thanks to today’s dehumidification system technology, this scenario might unfold (chronologically) as such:
Apparently, the 929-m2 (10,000-sf) natatorium he/she manages in a Toronto recreation centre just developed an operational problem needing immediate attention. The dehumidifier’s on-board micro-processor-based command centre, which maintains indoor air quality (IAQ) and energy-efficiency in the facility, just sent an emergency notification to his/her smartphone via the computer interface’s category-5 Ethernet connection to the Internet.
Calling the facility’s maintenance staff at this early juncture is not an option. In some cases, while maintenance staff might be able to fix the problem, they would likely need expert troubleshooting diagnosis and coaching. Instead, the facility manager uses his/her smartphone to log-in and connect to the dehumidifier’s on-board command and communication centre via Internet from the hotel where he/she is staying.
The dehumidifier’s command centre is accessed through a web browser-based software interface program for monitoring and controlling the natatorium’s environmental conditions and dehumidifier operations. The software program also e-mails alarm situations to the facility manager, his/her preferred local heating, ventilating, and air conditioning (HVAC) contractor, the manufacturer’s representative, the dehumidifier manufacturer, or any other user that is granted access.
After connecting to the dehumidifier, the web browser-based software interface displays the natatorium’s vital signs of relative humidity (RH), the space temperature, and the pool water temperature. Hundreds of other parameters vital to a comfortable and well-operating natatorium environment can also be viewed, depending on the access level granted by the manufacturer.
Besides the natatorium’s operating statistics, the alarm in question reads “HP1-TD” on the facility manager’s smartphone. The ‘HP’ stands for high pressure, the ‘1’ indicates compressor number one, and the ‘TD’ means a transducer sensed the high pressure and deactivated the dehumidifier.
Depending on the facility manager’s previous experience, if any, with this type of alarm, and his/her training on dehumidifier and natatorium fundamentals provided by the manufacturer, the facility manager can either instruct the maintenance staff to remedy the situation, or call the manufacturer.
In this scenario, the manufacturer’s factory technicians are able to troubleshoot the unit via the same Internet connection and the unit’s web browser-based software interface.
The factory’s diagnosis is a shutdown of an outdoor air cooled heat-exchanger fan, the part of the system that ejects heat to the outdoors when it is not needed inside the facility. The shutdown fan caused a high-
pressure reading and the high-pressure switch shutdown the entire system. Since it is not a reoccurring problem, the prognosis speculates a possible voltage spike from the utility might have shutdown the condenser fan.
Meanwhile, the facility manager is told to continue enjoying his/her family vacation because factory technicians will attempt to instruct the natatorium’s on-site maintenance staffer to scroll through the command centre’s on-board LED readout prompts to reset the system.
The system resumes operation, no further alarms are triggered, and the dehumidifier does not shutdown again while factory technicians monitor its many operating parameters via the web browser-based software interface. Factory technicians monitor the unit for a few days and the alarm does not reoccur, indicating the voltage spike speculation may have been correct.
While it might have taken 15 minutes of the facility manager’s vacation time, solving the problem helped keep the facility open. Equally important is the facility saved hundreds of dollars because the local HVAC contractor was not needed to troubleshoot and solve the alarm.
This scenario may seem unrealistic; however, this technology is, in fact, being used today. Thanks to the advancements in micro-processors, the Internet, and smartphones over the last 10 years, an aquatic facility manager can monitor and possibly control a natatorium’s environment from anywhere in the world.
Indoor pool dehumidifiers are complex mechanical machines designed with many safeguards that automatically trigger when operating conditions deviate from their set points or ideal operating ranges. These safeguards can react to low or no water flow, insufficient airflow, excessively high or low pressures in the refrigeration circuit, or any other operating abnormality. While a unit can conceivably run if operating conditions are not optimal, the dehumidifier’s vast number of switches, sensors, and transducers are designed to prevent the unit from internal damage and protect the facility’s investment.
Low airflow, for example, is another common alarm that occurs when an electronic air switch amid the dehumidifier’s airstream senses insufficient airflow. The notification is e-mailed to the facility manager or any other authorized personnel via the unit’s software system.
A dirty filter causing restricted airflow will commonly trigger a dehumidifier’s airflow switch, which signals the need for maintenance. Thus, ensuring the correct amount of conditioned air is supplied as well as return air brought back to the unit for proper dehumidification, cooling, and/or heating.
Prior to the influx of micro-processor technology on mechanical systems, an insufficient airflow event could also shutdown the dehumidifier by triggering the low-pressure (low-refrigerant) switch. As the malfunction (trip) was related to refrigerant pressure, it could have staff members and contractors troubleshooting the wrong thing. An HVAC service contractor would be called and after an hour or two of troubleshooting, the dirty air filter is discovered. The facility is billed a few hundred dollars for the service call which could have been avoided if the system was equipped with today’s software technology, which sends an alarm identifying the specific problem.
It might seem inconceivable for maintenance staff to not routinely change air filters on mechanical equipment, but it happens frequently, especially in schools, according to an article on outdoor air dehumidification in the June issue of the RSES Journal, a trade magazine for air conditioning and service technicians. The author, Len Kobylus, notes school maintenance staff (which are not too unlike aquatic facility maintenance staff or could possibly be the same personnel at high school indoor pools shared by the local community) do not frequently change mechanical equipment air filters because they are understaffed or not properly trained.
In addition to a service call, another cost associated with dirty air filters is the additional fan energy consumed during operation. Air cannot flow as easily through the media filter that is clogged with debris; therefore, the fan must work harder, which increases utility costs.
Detecting a dirty filter, via an insufficient airflow alarm e-mailed by the web browser-based software interface, will save operational costs if the filter is then replaced. Some software also allows authorized personnel to adjust the sensitivity of the sensor which detects insufficient airflow. The more sensitive these sensors are, notifications will be sent more frequently.
Further, operating a dehumidifier with clogged air filters will eventually lead to dirty coils that must be cleaned more frequently. A dirty coil also leads to poor heat transfer, which is another drain on energy in the system that will eventually raise operational costs, many times unbeknownst to the facility manager. Cleaning a dirty coil requires a much more expensive service call with respect to time and materials, which can amount to hundreds of dollars per visit, but can be avoided with a low airflow alarm.
A water flow issue is another common alert a facility manager may receive. Most modern dehumidifiers are designed with an energy-recovery feature that uses the refrigeration circuit’s compressor(s) waste heat to provide up to 100 per cent pool water heating. Essentially, this is free heat for the pool as the facility has already paid the utility for the cost of running the compressor(s) for dehumidification and cooling.
Many times an insufficient water flow alarm is activated because a valve to the dehumidifier was turned off. For example, valves are commonly forgotten after backwashing the filter. Without an alert, the system will continue dehumidifying, but pool water heating is automatically segued to the pool’s backup duty conventional gas-fired or electric water heater. Since pool heaters are not energy-recovery components, it is an unnecessary and wasteful cost for the facility.
While an error of this nature might seem inconceivable, there have been dozens, maybe hundreds of instances where manufacturer technicians have arrived at a site only to discover the pool water flow valve to the dehumidifier had been turned off. There are also many instances where the installing contractor never piped
the pool water to an energy-recovery dehumidifier at the facility inauguration many years prior. In both cases, the facility had been losing thousands of dollars annually in pool heating costs that could have been provided free by the dehumidifier.
Excessive water flow can also be an expensive problem. Besides being a waste of circulation pump energy, the higher water flow can actually erode piping and the pool heater. Pinpointing high water flow via web browser-based software interface communication will save the facility operating costs and prevent premature failure of water loop components.
By calibrating the software to send alerts to the facility manager, this wasteful scenario would not last more than a day. The facility manager can call the factory technicians to investigate, which will eventually be diagnosed as a closed valve.
All mechanical equipment needs periodical servicing. Unfortunately for equipment and facilities as complex as a natatorium, service frequency, in many cases, is required more than once a year. There are many types of system degradations that can reduce efficiency between an annual and/or semi-annual tune-up. The situation goes unnoticed by facility management because the dehumidifier system seemingly still dehumidifies, cools, and heats the natatorium adequately.
A good example of this is refrigeration circuit pressures. Everyone has experienced an air conditioning system, whether it is an automotive or residential unit, which underperforms because it is low on gas or refrigerant. Typically, a system loses refrigerant due to a leaking coil or connection. Nearly every coil leaks at least once during its lifetime. A dehumidifier coil that has a slow leak can progress for months, sometimes a year, before uncomfortable environmental conditions in the natatorium are felt by occupants. Meanwhile, the dehumidifier operates inefficiently because the compressor will run longer or cycle more frequently. As a result, utility costs can increase dramatically before the next routine service call detects the problem.
A web browser-based software interface program will detect this type of degradation once it surpasses a threshold set point calibrated by the manufacturer or the facility manager. A low-pressure alarm, sometimes indicated as “LP-Vac” will indicate a low-pressure situation. The advantage is the facility manager is alerted to the situation the day it occurs, not months later. Instead, the system is brought back to the manufacturer’s specified operating pressures before months of inefficient operation ensues.
A call to the manufacturer might help detect the cause of the low-pressure problem; however, a web browser-based software interface can further assist troubleshooting efforts in a number of ways. For instance, other sensors may have been highlighted such as a low-pressure transducer, low-pressure switch, or even a high-suction temperature caused by a unit low on refrigerant. Even though the dehumidifier is updated in real-time every minute, 24-7, its data can also be historically recorded for many days by the manufacturer’s factory server. This historical analysis can be helpful when trying to spot certain trends.
Of course, a serious refrigeration problem, such as a leak, cannot be resolved by the facility’s maintenance staff if they do not have the proper certification; however, the factory diagnosis can be invaluable for saving troubleshooting time for a local HVAC service contractor with little to no natatorium dehumidifier experience.
Ralph Kittler, P.Eng., is co-founder and vice-president of sales and marketing of Seresco Technologies Inc., an Ottawa-based manufacturer of natatorium mechanical dehumidifiers and outdoor air ventilation only systems (OAVOS). He has 25 years of experience in the heating, ventilation, and air conditioning (HVAC) industry and a degree in mechanical engineering from Lakehead University in Thunder Bay, Ont. Kittler serves on the Model Aquatic Health Code (MAHC) advisory board of the Center for Disease Control (CDC), as well as two technical committees of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). He recently produced a free ‘Professional Development Hour’ (PDH) video available at www.serescodehumidifiers.com, which targets the continuing education requirements for engineers, but also serves as an invaluable primer of indoor pool design and operation basics for facility managers. He can be reached via e-mail at email@example.com.
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