Reducing refrigerant use
Since the Kyoto Protocol global environmental treaty in 1997, ozone-depleting chlorofluorocarbon (CFC) refrigerants such as R-11 (trichlorofluoromethane) and R-12 (dichlorodifluoromethane) have been phased out and replaced with more environmentally friendly options such as R-410A (a mixture of difluoromethane and pentafluoroethane) and R-407C (a mixture of hydrofluorocarbons).
While these newer refrigerants are less harmful to the environment (i.e. ozone depletion), they can cost up to 10 times as much as the refrigerants they replaced. They also comprise blends of two or three refrigerants, which need to be in exact concentrations to ensure optimal HVAC performance. Further, operators are also faced with more expensive and challenging onsite refrigerant-related service issues. When compared to air conditioning systems, this becomes more significant because traditional indoor pool dehumidifiers have considerably larger refrigerant charges. Until recently, most large community indoor pools, YMCAs, and school natatorium dehumidifiers would have systems with hundreds of kilograms of refrigerant in their circuits; therefore, a refrigerant leak could easily cost thousands of dollars in replacement costs alone.
In terms of new indoor aquatic facility construction, designers are also faced with additional considerations regarding compliance to American National Standards Institute (ANSI)/ASHRAE Standard 34-1010, Designation and Safety Classification of Refrigerants, and ASHRAE Standard 15-2010, Safety Standard for Refrigeration Systems, regarding safe refrigerant concentration limits in occupied spaces.
When considering these challenges related to new refrigerants and mandates, by far the most important innovation in dehumidification equipment has been the recent move toward refrigerant reduction. Rather than using a conventional ‘split system,’ where refrigerant is piped outdoors to a remote air-cooled condenser, these systems now reject heat into a propylene glycol fluid loop, which then goes outdoors to an air-cooled heat exchanger called a dry-cooler. Propylene glycol is environmentally friendly and 95 per cent less costly per kilogram than today’s refrigerants. Further, a refrigerant charge can now be reduced by as much as 85 per cent compared to conventional dehumidifiers.
Although new to the indoor pool industry, this dehumidification technology has been used in computer room air conditioning systems and environmentally sensitive areas for a number of years.
Innovations to consider
Today’s advancements in dehumidification equipment design offer natatorium operators and owners unprecedented performance, reliability and energy savings. Further, these innovations contribute to increased operating efficiencies, five to seven per cent for normal days (under 35 C [95 F]) and the same overall efficiency on the hottest summer days (above 35 C).
Therefore, natatorium operators and owners should consider these new technologies when analyzing their current equipment’s efficiency, environmental impact and overall operational costs. A new dehumidification system could have an attractive ROI and deliver better overall performance.
Ralph Kittler, PE, is co-founder and vice-president of sales and marketing at Seresco Technologies Inc., an Ottawa-based manufacturer of natatorium dehumidifiers. He has 23 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 is also an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) ‘Distinguished Lecturer’ and technical committee 9.10 reviser for Chapter 25, Mechanical Dehumidifiers and Related Equipment in ASHRAE’s 2012 Systems and Equipment Handbook, and technical committee 9.8 reviser for Chapter 5, Natatorium Design in (Large Building Air conditioning Applications) in ASHRAE’s Applications Design Handbooks since 1999. He can be reached via e-mail at ralphkitter@serescodehumidifiers.com or by visiting www.serescodehumidifiers.com.
