ASHRAE Journal - December 2014 - 100

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Oregon School District Goes to School with Buderus Boilers from Bosch
Back-to-Back New and Retroﬁt School Projects
Buderus high mass SB Series commercial boilers from
Bosch Thermotechnology have proven to be a reliable and
ﬂexible product for the Redmond School District in central
Oregon, located just east of the Cascade mountain range.
Since 2012 the Redmond School District has utilized
Buderus SB boilers in both a newly built high school and in
an existing high school that underwent extensive remodeling
along with a mechanical room upgrade. SB Series boilers
are high efﬁciency condensing boilers that can use a range
of fuels - natural gas, LPG and oil - providing ﬂexibility for
both retroﬁt and new construction projects.
In 2012 the district constructed a new $73 million 280,000
sq. ft. high school to meet growing student enrollment needs.
The Ridgeview High School incorporated four Buderus
SB615 condensing boilers ﬁred by liquid propane tied into a
VRV system controlled by a Honeywell WEBS HVAC DDC
control system. Multi-zone air handlers with refrigerant fed
coils installed within the building's ductwork supply heating
or cooling throughout the school, which earned LEED
Gold certiﬁcation, due in part to optimizing its mechanical
systems' energy performance. Energy savings using the
Buderus SB615 boilers are projected to be between 20% and
25% of a standard code-compliant system.
By 2013, the district's namesake Redmond High School,
opened in 1970, was in need of interior renovations to its
classrooms, gym and mechanical room comfort generation
equipment. Two original 60,000 lb. water-tube boilers and
a heat exchanger needed replacement, and again the district
selected the Buderus SB Series for the upgrade. For this
application three SB745 gas condensing boilers were installed
on a newly laid pad, and tie into an existing header while
allowing sufﬁcient space for electrical equipment and ﬂues.
"I used Buderus boilers as the basis of design because, in
part, I had good experiences with them in previous projects,"
comments Scott Miller, P.E. of MFIA, Inc. consulting
engineers. "We knew from previous experiences that they are
very efﬁcient. In this case, the added incentive was the ability
to use heating units that looked and performed like those in
other schools. There was initial hesitation on the owner's part
due to other school district "horror stories" with condensing
boilers. But when I showed them how the Buderus boilers
looked and operated there was a willingness to try them. At
Ridgeview we needed the efﬁciency for LEED purposes. By
the time we got to Redmond HS, the owner asked that we
design around the Buderus product."
Buderus SB Series at a Glance
Stainless steel Buderus SB Series gas condensing boilers
are ideal for large projects, both new construction and
retroﬁt. Equipped with a two-staged or modulating forced
draft burner, they minimize pollutant emissions. They are
equipped with two return water connections, which allow for
separate return ﬂows and optimal efﬁciencies up to 98%with
inputs of 563 to 5443 MBH.
When return-ﬂow temperatures are reduced below
the dew point of combustion gases are reduced further,
additional heat is reclaimed from the ﬂue products. In the
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SB Series, low ﬂue gas temperatures are ensured by low
return water ﬂow temperatures, highly efﬁcient titaniuminfused stainless steel heat exchanger surfaces, heating
units, and continuous operation.
Boiler insulation comes pre-installed in the SB Series and
convenient top connections allow easy access for piping,
reducing installation effort. Project costs for SB Series boilers
are reduced due to simpliﬁed piping, and their high water
content heat exchangers require no minimum ﬂow rate, which
eliminates the need for a costly dedicated boiler circulator.

Project Essentials

Project Name: Ridgeview & Redmond High
Schools
Buildings Owner: Redmond School
District, Redmond, Oregon
Application: Hydronic heating with VRV
Equipment: Buderus SB615 (LP) & SB745
(natural gas) condensing boilers
Engineer: MFIA, Inc., Portland, OR
General Contractor: Skanska, Portland OR
Manufacturer's Representative: PacWest
Sales, Portland, OR
Project Completion: 2012-2013
Ridgeview HS awarded LEED Gold certiﬁcation

ASHRAE Journal - December 2014

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