Multifamily Performance and Value
Improved HVAC Systems
One of the reasons is the use of a geothermal cooling and heating system, which comprises 335 water-source heat pump systems in individual packaged units for each condominium, which transfer heat via a single- or two-pipe water loops. Each unit can be used in either heating or cooling mode year-round, and loop temperature is maintained via the building's boilers and cooling towers. “Each zone within the tower has complete control of its heating or cooling mode and each unit is independent from the others,” says ClimateMaster's Landers. “High-rise applications in downtown areas have been among the largest markets for these systems, and they are coming back, thanks in part to aggressive energy plans like the one for Museum Tower.”
For the multifamily building operator, using a renewable energy technology like geothermal affords several benefits. “The main goal was two-fold—to be able to submeter the electrical usage of each condo unit, and also to achieve an ultra-high level of efficiency with the HVAC system's operation,” says Jake Musick, P.E., project manager at Blum Consulting Engineers. “A heat pump-driven system helped us to achieve both aims, while also providing the quiet operation expected in a residence of such luxury caliber.”
For the 234-unit Millennium Tower in New York City's Battery Park, unitized water-to-air heat pumps are used for geothermal heating and cooling. Photo courtesy of ClimateMaster |
Recent applications of geothermal for multifamily projects like Museum Tower and the 234-unit Millennium Tower in New York City's Battery Park rely on the unitized, small-footprint units that can fit inside individual living areas.
Similar to new unitized and ductless air-conditioning systems, these water-to-air heat pumps come in compact, vertical-stack units that can be located in coat-closet-sized mechanical rooms, typically off of a living room or bedroom. The package units are tightly insulated, especially for the geothermal systems, which transport water that is colder than cooling tower feed.
“Just as important is the ability to submeter each unit, so you can tell how much each unit is using for heating or cooling,” says Landers. “Using geothermal loops, a multifamily building can sell BTUs for heating or cooling, and submetering gives the building owner or property manager control over that.”
The use of submeters for multifamily buildings has a long history, but recently use of the systems have taken off for both energy tracking—for electric and gas—and, increasingly, water monitoring. The most common scheme employs individual meters installed in each condominium or apartment and networked together using wireless radio-frequency (RF) communication systems, allowing for remote meter reading. Simple software programs collect the usage data and generate bills ready to mail or email to residents; for their part, the building owners simply pay the utility one bill as clocked by the master meter.
Beyond the benefits of passing along the costs fairly to tenants, some multifamily owners have adopted submeter products because of local utilities and municipalities offering incentives to use them. As an example, the East Bay Municipal Utility District in Oakland, California, offers apartment building owners a rebate up to $250 per dwelling unit for installing submeters. The utility also offers up to $150 per unit for condominiums and townhouse homeowner associations, or HOAs.
Notice
(Pictured: Marselle Condominium, Seattle, WA. PB Architects. Photo by Matt Todd Photography, courtesy of WoodWorks.)
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- Used in geothermal and water-source heat pump applications
- Exceeds ASHRAE 90.1 efficiencies with twostage operation
- Uses EarthPure® (HFC-410A) zero-ozonedepletion refrigerant, making it an extremely environmentally friendly option
- Its multiple cabinet configurations and small footprint make it suitable for tight installations and for replacement/retrofit markets
- Features iGate technology, the next generation in intelligent control by using two-way communication to provide a gateway to the system.
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