ASHRAE Journal - September 2020 - 19

TECHNICAL FEATURE

operating at lower inputs with the same HX surface area
results in a more efﬁcient heat transfer. This is converse
to more traditional non-condensing, high-mass boiler
plants that ﬁre to 100% before bringing on the next unit.

plant warranty and optimized performance.

Summary

In a multiboiler plant, one unit serves as the "manager"
while the others are "clients." Advanced controls establish
the next in command if the "manager" is ofﬂine due to
maintenance, repair or other issues. Advanced controllers can make this shift automatically to eliminate short
cycling and ensure optimal operating efﬁciency.

Designing a heating and hot water plant for maximum efﬁciency and performance requires engineers
to consider several factors from the outset. Recognizing
the speciﬁc needs of the facility, selecting the proper
high-efﬁciency condensing boiler to best meet the load
requirements, integrating advanced controls and incorporating the optimized loop design early in the process
will save installation time, lower construction and operation costs and deliver superior performance.

Remote Access

References

Backup Manager

Arming the facility owner and maintenance personnel
with remote monitoring reduces the time spent physically monitoring the system. When it is combined with
maintenance and service alerts, the maintenance team
is immediately notiﬁed of issues that may improve performance or reduce tenant complaints. The staff is also
made aware so it can provide maintenance to help keep

1. AERCO. 2013. "Benchmark 2000 Efﬁciency
Curves."
2. 2016 ASHRAE Handbook-HVAC Systems and
Equipment, Chap. 32, Figure 7, "Relationship of
Dew Point, Carbon Dioxide, and Combustion
https://bit.ly/3k9ecVE
Efﬁciency for Natural Gas."
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3. 2019 ASHRAE Handbook-HVAC Applications,
Chap. 51, Figure 25, "Sizing Factor for Combination Heating and
Water-Heating Boilers."
4. ASHRAE. 2013. "Weather Data Viewer, version 5.0 (CD-ROM)."

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ASHRAE Journal - September 2020

Table of Contents for the Digital Edition of ASHRAE Journal - September 2020