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)