 |
 |
 |
| :: Product Search |
|
|
 |
|
|
|
|
Montreal, May 1, 2007 - Dectron Internationale (TSX: DTL):, a leader in the heating, ventilation and air conditioning, indoor air security and water generation markets, is pleased to announce its financial results for the fiscal year ended January 31, 2007 (in thousands of Canadian dollars) ...
|
|
|
 |
 |
|
|
 |
 |
|
|
|
 |
 |
|
|
|
|
 |
|
|
| Dectron DRY-O-TRON |
August 9, 2003 |
|
No Refrigerant Allowed in the Building?
No Problem For Engineer's Custom
Dehumidifier Strategy.
Engineer specs a glycol dehumidifier to comply with city code that prohibits refrigerants near pre-schoolers.
CHICAGO Although 95 percent of the swimming pool heat recovery dehumidifier market is dominated by direct expansion (dx) units, the Chicago Board of Education (CBOE) challenged Primera Engineers Ltd., to design a pool dehumidification system without refrigerant heat exchangers in the building or in the air stream.
The CBOE's new state-of-the-art 110,000-square-foot Cermak Elementary & Teaching Academy includes an attached 45,000-square-foot community center with a swimming pool-all designed by architect, De Stefano & Partners, Ltd., Chicago. Ordinarily, specifying a dx style dehumidifier would have been an easy task for the community center's 6,000-square-foot recreational natatorium design; however city codes prohibited the use of refrigerant-based equipment because the same building also hosts a daycare center.
"The city doesn't want refrigerant-based equipment around children under two years old because they're too young to vacate the building by themselves in the event of a refrigerant leak," explained Michael Belczak, senior associate/mechanical engineer, and one of 60 design professionals at Primera Engineers Ltd., Chicago, a 15-year-old full service engineering/architecture firm.
Primera's design team found only two manufacturing candidates willing to build a custom heat recovery dehumidifier that would use a few dozen gallons of 42°F ethylene glycol instead of the customary hundreds of pounds of R-22 refrigerant that's typically used in conventional dehumidifiers. The winning manufacturer, Dectron Internationale, Roswell, Ga., built a custom dehumidification system to Primera's specifications via manufacturer's representative, Imbert Corp., Niles, Ill. The system is split into a mechanical room air handler (model Dry-O-Tron® DG-182) and a 60-ton rooftop chiller (OCS-802-1H2-9 manufactured by its RefPlus division). While the chiller uses refrigerant, its remote rooftop location poses no threat because the refrigerant and the air stream of the air handler are separated by 30 feet of glycol piping installed by project mechanical contractor, Ortiz Mechanical, Orland Park, Ill.
The energy-conscious Primera specified a recycling dehumidification system that maintains a 50% relative humidity by removing a capacity of 200 lbs. of moisture/hr. while also heating the pool water and heating/cooling the space to 83°F and 82°F temperature set points respectively. The challenge for Ref-Plus's in-house engineers was fulfilling Primera's project goals of designing a custom air-cooled and water-cooled chiller. The condenser loop hot water is used for pool water heating and air reheat. Once the pool water and space heating has been satisfied, the chiller rejects heat to the air-cooled condenser.
In winter operation, heat generated from the chiller process is transferred to the pool area for space heating. In the event the dehumidification process can't totally supply pool water heating, a back-up 715,000-BTU boiler activates.
Dedicated Pool System
Even though the school has a chilled water loop supplied by a main chiller plant-two 215-ton air-cooled chillers by Carrier Corp., Syracuse, NY, that feeds air handlers with 45°F chilled water throughout the school--Primera chose to keep the school and natatorium systems separate mainly because of uncommon schedules. "Based on our experience of designing indoor pool spaces in the past, it seems to work out best when the pool system is separate from the rest of the building," Belczak said. "Plus, the school can maximize its energy savings this way because the dehumidification system runs 24-hours per day, while the rest of the school has downtimes during nighttime and vacation days."
In the same separation strategy, the pool area is monitored and controlled by the Dry-O-Tron's on-board microprocessor. However the school/community center's Carrier DDC building automation system also monitors the natatorium's vital statistics, while also carrying the ability to enable/disable the dehumidification system.
Another concern in the design is outside air. Total air input in the pool room is 23,000 cfm, however 4,250 cfm is outside air according to the city's requirement for pools based on square footages. That amount is sufficient if the maximum occupancy of 150 participants and 65 spectators is reached, according to Belczak.
Primera's Air Distribution
Because the pool room has no windows and only one exterior wall, Primera felt it could save the project money by eliminating under-deck air distribution that is many times combined with overhead air to keep windows condensate free. Instead, Primera designed a perimeter air distribution system approximately 25-feet high using 36-inch-diameter, single-wall, painted spiral metal duct with registers every 10 feet.
The mechanical room housing the air handler and pool equipment was located conveniently in a second floor mezzanine. The supply duct entrance and return air grill are efficiently located on a wall that separates the mechanical room from the pool.
Glycol Systems Might Be The Future
Primera's decision for a separate system also saves the CBOE tens of thousands of dollars per year in energy savings. If the compressor heat of the rooftop chiller package isn't recovered by the dehumidification system to heat the pool water, all that energy would have been wasted according to Ref-Plus President, Michel Lecompte.
The energy savings is important because the introduction of a secondary heat transfer fluid, such as the glycol loop, versus its dx refrigerant counterpart results in a 10 percent efficiency loss, estimated Belczak. To compensate for the efficiency loss, the dehumidification coils are slightly larger than a conventional dehumidifier.
The CBOE's strategy of restricting refrigerant inside of buildings is an idea Dectron has been considering in light of the safety and rising cost issues of refrigerants, according to Lecompte. Safety is always an issue with any unit using hundreds of pounds of pressurized refrigerant in an occupied space. Plus, rising costs of R-22 due to a government mandated phase-out and current high prices for HFC alternatives is interesting Dectron in glycol systems. A glycol system uses a 75 percent less refrigerant charge used in conventional dehumidification systems, plus it allows the refrigerant portion of the system to be located outside of the occupied space.
With the success of the Cermak Elementary pool space concept and application, the CBOE and its project engineer, Primera, might be pioneers in what someday might become a future standard for natatoriums.
|
|
|
|
|
|
 |
 |
|
