Chapter hvac engineering Fundamentals: Part 1 Introduction

6.8
Refrigerant Distribution
The pumping of liquid refrigerant from condensing units to points of
use is common practice in the cold-storage industry but is seldom used
in HVAC work. To properly design such a system requires an extensive
and specialized background in refrigerants and refrigeration machin-
ery which is beyond the scope of this book.
6.9
Summary
The distribution of thermal energy by means of heated or cooled fluids
from a central plant to points of use is a common HVAC practice. The
process uses energy which contributes nothing to the final air-
conditioning result; therefore the transport energy is said to be ‘‘par-
asitical.’’ Thus, the transport system should be designed to use as little
energy as possible. Some methods for accomplishing this include (1)
using a large
⌬
T
for water systems to minimize flow rates, (2) mini-
mizing water velocities and pressure drops (without greatly oversizing
piping), (3) using variable-speed or staged pumping, and (4) using sec-
Design Procedures: Part 4
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