ASHRAE Journal – Balancing Variable Flow Hydronic Systems-Taylor & Stein
By Steven T. Taylor, P.E., Member ASHRAE,
and Jeff Stein, P.E., Member ASHRAE
Steven T. Taylor, P.E., is a principal and Jeff Stein, P.E., is a senior
engineer at Taylor Engineering in Alameda, Calif. Taylor is a member of
TCs 4.3 and 1.4. He is a former member of ASHRAE Standing Standards
Project Commitee (SSPC) 90.1 and former chairman of SSPC 62.1.
how, and indeed whether, to balance variable flow (twoway
valve) hydronic systems has been debated for many
years.1,2,3 In most of the literature, either the analysis has
been limited to only a few of the many balancing options, or analyses of flow control problems and their
energy impacts were based on simplified or atypical hydronic systems. Few references compare in detail the
first costs and energy costs of the various balancing options. This article attempts to fill these gaps by analyzing
the balancing of variable flow systems in a detailed and comprehensive manner.
Features of the analysis include:
• Seven of the most commonly used methods for balancing
hydronic systems are addressed.
• Two HVAC system applications are analyzed, one chilled
water system and one hot water system, both of which are based
on a real building.
• Flow through the system for each of the balancing options
is analyzed using a commercially available pipe network analysis
program that accurately models flow through all design
elements as flow and pressure varies through the system.
• First costs and energy costs of each balancing option are
estimated.
