Heating Systems for Buildings 1

HEATING SYSTEMS FOR BUILDINGS

WARM AIR HEATING

Warm Air Heating

Warm Air Units are similar to air conditioning units in the way that they blow air around ductwork and out through grilles or vents throughout the house. The air is normally heated by way of a gas burner and is controlled by a room thermostat and a time switch.

Basically, the operation of a forced warm air system is quite simple. Circulating return air enters the furnace where a filter or electronic air cleaner traps air borne dirt.

FURNACE

FURNACE

Furnace types Single-stage Two-stage Modulating

DUCTS

constructed of sheet metal or glass fiber- either round or rectangular.

are used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air. The needed airflows include, for example, supply air, return air, and exhaust air.

DUCTS

DAMPERS

these will be necessary to balance the system and adjust it to the desires of the occupants. Splitter dampers are used where branch ducts leave the larger Trunk ducts. Each riser can have its flow controlled by an adjustable damper in the basement at the foot of the riser, labels should indicate the room's served.

DAMPERS

DAMPERS

HOT WATER AND STEAM BOILERS

OIL-FIRED STEEL BOILERS

A refractory chamber receives the hot flame to the fire. Combustion continues within the chamber and the fire tubes. Smoke leaves through the breeching at the rear. Water, outside the chamber. Receives the heat generated in the combustion chamber. If the domestic hot water coil is connected for use, a larger capacity boiler is selected.

OIL-FIRED STEEL BOILERS

GAS-FIRED

Cast iron hot water boiler Cast iron sections contain water that is heated by gas from below the unit.

Output is related to the number of sections.

GAS-FIRED

OIL-FIRED

Cast iron hot water boiler primary and secondary air for combustion may be regulated at the burner unit.

OIL-FIRED

ELECTRIC BOILERS

For hot water heating are of high capacity output. Electric steam boilers are also commonly used in large buildings.

ELECTRIC BOILERS

COAL-FIRED STEAM BOILER

As less polluting use of coal is achieved, a return of this variation of equipment is seen.

HOT WATER HEATING SYSTEMS

HOT WATER HEATING SYSTEMS

TYPES: CIRCUIT TYPES SPECIAL FITTINGS AIR VENTS AND WATER DRAINS HYDRONIC AND ELECTRICAL

CONTROLS CIRCULATING PUMP

CIRCUIT TYPES

CIRCUIT TYPES

There are four (4) principal methods of arranging the piping for the circulation of hot water to the heating elements located in the spaces to be heated.a. Series Perimeter Loop b. One-Pipe Systemc. Two-Pipe Reverse-Returnd. Two-Pipe. Direct Return

a. Series Perimeter Loop

Runs in the perimeter of the house Water flows to each baseboard or in

tube in turn. Values at each heating element are

not possible since any value would shut of the entire loop

Series Perimeter Loop

b. One-Pipe System

Has special fittings which divert part of the flow into each baseboard

A value may be used at each one to allow for reduced heat or complete shut off to conserve energy

Not that economical

One-Pipe System

c. Two-Pipe Reverse-Return Not always necessary Boiled water supplied to each

baseboard Not being cooled by passing through

previous baseboards Equal flow is achieved through all

baseboards by reversing the return

Two-Pipe Reverse-Return

d. Two-Pipe. Direct Return This system is not much favored the path of water through the first

baseboard is much shorter than that through the others

the last baseboard could easily be undesirably cool, since it is short-circuited by the others.

Two-Pipe. Direct Return

SPECIAL FITTINGS

SPECIAL FITTINGS

Venturi-type jet tee used here. In the return branch connection to the main it induces flow through the convector by retarding the flow to force water into the supply branch and producing a jet to reduce the pressure in the main following the return branch.

SPECIAL FITTINGS

AIR VENTS AND WATER DRAINS

AIR VENTS AND WATER DRAINS Except for the necessary air cushion

in the upper part of the compression tank above the boiler, air must not be allowed to accumulate at high points in the piping or at the convector branches. These air vents relieve these possible air pockets. which would otherwise make the system air-bound and inoperative

AIR VENTS AND WATER DRAINS

HYDRONIC AND ELECTRICAL CONTROLS

HYDRONIC AND ELECTRICAL CONTROLS Hot Water heating systems are fully

automatic and operate as controlled by methods described in the figure. Makeup water is added as required, the air level in the tank is regulated by the air control, fittings, and the circulator and burner operate as controlled by the aquastat and thermostat. If the air vents in the piping are not automatic they will require periodic manual "bleeding" of unwanted air.

HYDRONIC AND ELECTRICAL CONTROLS

CIRCULATING PUMP

A centrifugal pump is selected to overcome the friction-of-flow in the piping and fittings and to deliver water at a rate sufficient to offset the hourly heat loss of the house or buildings.

CIRCULATING PUMP

FIRE PLACES

FIRE PLACESTYPES: CONVENTIONAL MASONRY FIREPLACE - often used

where there is wide space and you can afford it. But conventional fireplaces are about 10% efficient.

HEAT CIRCULATING FIREPLACE- This give off as much radiant heat as conventional types, but to this they add circulating air warmed by convection.

PRE-BUILT FIREPLACES- This type of fireplace makes it possible to install a wood burning fireplace without concrete footings, without a masonry chimney, at lower cost, and in a room where structural considerations would otherwise rule out a fireplace

ELECTRIC RESISTANCE HEATING

ELECTRIC RESISTANCE HEATING This procedure permits a method of operation

that can contribute to the saving of energy. Temperature in rooms that are not in use, can be lowered or the room units turned off by means of a switch. Thus the rooms actually occupied would be the only ones to draw full energy. Baseboard and drop-in-units have a fast response. The electric-radiant-ceiling method has largely supplanted the earlier radiant heating that employed hot water coils in ceilings or floors. The radiant-heating cable is installed ready for completion of plaster ceiling.

ELECTRIC RESISTANCE HEATING

ELECTRIC RESISTANCE HEATING

ELECTRIC RESISTANCE HEATING