Commercial Architecture April 2019 - 43

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PROJECT

| hvac

"It's not merely about meeting a standard, but simply
implementing the smartest possible building-science
principles," said Gifford. "That means integrating all
building systems (insulation, water, lighting, and heating, cooling, and ventilating) into a cost-effective, holistic solution. That's why a device like the Danfoss thermostatic radiator valve plays a big role in creating a
comfortable, energy-efficient building."
A THERMOSTAT FOR EACH ROOM

One of Gifford's design principles is that each room
should have its own thermostat.
Gifford explained, "If a simple building with only
two rooms is located where the sun shines from one
direction and the wind blows from another direction,
the heating and cooling loads will vary between rooms.
Putting a single thermostat in one room will keep that
room warm, but leave the other too hot or cold. Plus,
internal loads will vary depending on cooking, showering, computers, and lighting. The temperature imbal-

To avoid balance problems, each room was provided with a radiator controlled by its own Danfoss RA2000 thermostatic radiator valve (TRV).

ance becomes very noticeable if the building is well insulated. People will run space heaters in winter to heat the
cold room, and/or open windows in a hot room. That's

"Psychological studies show that when people have

than 55 F, serving the entire building. The Danfoss

a huge waste of energy, and it makes the air dry and

control over room temperature, they tend to be more

valves on each radiator control flow through the radiator.

unhealthy."

satisfied with their environment," he noted. "That's par-

The bottom line for the Passive House design: The

To avoid balance problems, Gifford specified each

ticularly valuable in mild weather when controlling tem-

space heating cost for each apartment averages about

room at 803 Knickerbocker with a radiator controlled by

perature is difficult and a lot of energy is wasted due to

$44/yr. in a building constructed for the same cost/sq. ft.

its own individual thermostat.

overheating."

as any other NYC affordable-housing facility.

control makes the whole apartment comfortable without

REWARDING ENERGY SAVINGS

aesthetics of 803 Knickerbocker have been widely recog-

wasting energy by overheating or overcooling. This

Using room thermostat control in the integrated build-

nized. It was the first midsized apartment building in the

allows the system to be downsized, which saves enough

ing design has produced extraordinary energy savings.

United States to be certified to the Passive House stan-

money to more than pay for the additional thermostats."

Despite its 34,581 sq. ft., the property's peak heating load

dard, and was recognized in New York City Mayor Bill

is only 127,000 Btu/hr.

de Blasio's One City Built To Last program as an innova-

Gifford observed that, "individual-room temperature

To regulate the flow of hot water through the radia-

The ultra-low energy performance, comfort, and

tors, Danfoss RA2000 TRVs with a tamper-resistant

"This is an incredibly low heat load for a building of

non-electric operator were used. The RA2000 TRV is

this size," said Gifford. "But, just because the load for

The building is further proof that an integrated,

designed for hot water or low-pressure steam. In this case,

space heating goes down doesn't mean the domestic hot

holistic approach to design is practical. It also has helped

the valves were installed on wall-mounted baseboard

water load is reduced. We put two small, sealed-combus-

spur changes in NYC building code and zoning regula-

radiators to avoid coordination difficulties between

tion gas boilers in a mechanical room on the roof. The

tions to enable construction of more ultra-low-energy

flooring installers and plumbers.

boiler capacity is primarily used to make domestic hot

buildings.

tive approach to reducing the city's carbon footprint.

The TRV regulates hot-water flow by using an inte-

water and, secondarily, heat the building, which is oppo-

grated thermostat and valve assembly. A white knob con-

site from the responsibility of most boilers in other

taining a sealed capsule filled with a heat-sensitive vapor

buildings. We have four storage tanks for the domestic

Gifford noted, "Since 803 Knickerbocker opened in

charge functions as the thermostat. If the room is too

hot water, and we use the smallest, most efficient pumps

2014, there have been zero tenant complaints about

warm, the rise of temperature increases the vapor pres-

possible to circulate water in the hydronic loop."

heating. When you can make both tenants and property

sure in the bellows, closing the valve. If cold, the pressure

A 1/8-hp pump supplies a two-pipe hot-water system,

decreases, opening the valve. In typical operation, the

which runs whenever the outdoor temperature is lower

However, most important to Gifford is the legacy of
comfortable tenants and property owners.

owners happy in Brooklyn, it shows using thermostatic
radiator valves for every room really works." CA

valve is not either fully opened or closed. Rather, it modulates between open, closed, or partly open based on a
proportional difference between actual and desired temperatures.
With the TRV, controlling space temperature is easy.
The apartment resident turns the knob to the desired
temperature. The dial is scaled in five increments about
5-deg. F apart, ranging from 57 F to 79 F. Gifford set the
upper temperature limit to 73 F, but residents can lower

Want more information from Danfoss (danfoss.com)? Circle 3 on the Reader Service Card.
Sources listed below are linked at commercialarchitecturemagazine.com/1904danfoss.

* New York City's Department of Housing Preservation and
Development, nyc.gov/hpd

* Chris Benedict, R.A.,
linkedin.com/in/chris-benedict-2abb8bb/

* Ridgewood Bushwick Senior Citizens Council, riseboro.org

* One City Built to Last, www1.nyc.gov/site/builttolast

the temperature setting, if desired.
COMMERCI A L A RCHI T EC T UREM AG A ZINE.COM

APRIL 2019

http://www.danfoss.com http://www.commercialarchitecturemagazine.com/1904danfoss http://www.nyc.gov/hpd http://www.linkedin.com/in/chris-benedict-2abb8bb/ http://www.riseboro.org http://www1.nyc.gov/site/builttolast

Commercial Architecture April 2019

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