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Heating Systems
HVAC 11a
CNST 305 Environmental Systems 1Dr. Berryman
11a Heating Systems; Fuels; Boilers; Furnaces; Hydronics, Radiant Heat
Chapter 5 (Toa)
Types of Heating Systems
Energy Sources
Circulating Air Systems
Heat distributed by an air stream through a heating unit to supply ducts
duct< 200’
Must make good cost projections to assure an economical selection
Simple Basics
Heating Units - Air
Split System -
w/ Gas Furnace
upflow
downflow
horizontal
Heating Units (cont.)
Single Package
w/ electric heating
Water SystemsHeat is distributed
by a pumped water system though a heating unit to supply piping boiler onboiler on
cooling towercooling toweroffoff
Different piping arrangements are used – Hydronic Piping
Boilers Water Tube – Low Fire Box
Gasses pass around tubes Responds quickly to load
fluctuations. Types range from small
(residential) to large (commercial)
Water Tube – High Fire Box
Boilers (cont.)
Piping Configurations Series Loop One Pipe Two Pipe Three Pipe Four Pipe
One pipe system
Series Loop Maintenance or repair requires
shutdown Temp control at each unit
impossible # units limited Only heating or cooling
One Pipe System Allows for each unit to
be controlled Limited # of units that
can be serviced Needs special fittings Only heating or cooling
Diverting Tee
Two Pipe – Reverse Return Each unit fed by individual supply branch Each unit can be controlled Flow rates are balanced (heat or cool only)
Three Pipe System Similar to two pipe systems Allows for simultaneous heating and
cooling Mixed return Prohibited by some energy codes
Four Pipe System
It is actually 2- two pipe systems Allows for simultaneous heating and
cooling Separate water return for heating
and cooling Most efficient Most expensive – initial cost
Steam Expands 1000 its original state
Creates its own transport system No pumps
Piping configurations same for water – only at low pressures Operating temps 220 – 250oF About 15 pisg
High Pressures (60 – 350 psig) Use heat exchanges Need steam traps
Steam to Water Heat Exchanger
Circulating pump
Steam in tube
Water in tube
Radiant Systems
Fin-tube radiator
Iron Sectional
Next Time Basics of Air Conditioning
12 Cooling Systems; Refrigerants; Condenser/Evaporator Compressive;
Absorption; Evaporative; Chillers; Heat Sinks
Chapter 4 (Toa)