Air Conditioning Contractors of America
Manuals D, J and S
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Air Conditioning
Contractors of America (ACCA) has provided 5 informative manuals pertaining to
residential HVAC systems. Of these ACCA manuals D, J, and S contain information
that is directly relevant to HVAC system function, design and efficiency.
Residential duct
systems have a direct and significant effect on equipment size, equipment
efficiency, equipment malfunctions, envelope infiltration, operating cost,
utility demand loads, vent performance, exhaust system performance, indoor air
quality, ambient noise, occupant comfort and owner satisfaction. Therefore, the
duct system must be carefully designed and properly installed or the potential
benefits that are associated with building an efficient structure and using
high efficiency equipment will not materialize.
ACCA manual D presents
the methods and procedures that should be used to design residential duct
systems. The subject material includes information about system selection
(constant volume or variable volume), system performance characteristics, duct
materials, blower performance, airside devices and duct sizing procedures. ACCA
manual D also includes information about duct system efficiency and the
synergistic interactions between the duct system, the envelope, the HVAC
equipment, the vents and the household appliances. Indoor air quality, noise
control, testing and balancing also are discussed. Other ACCA manuals that
pertain to residential HVAC system design include Manuals J (loads), S
(equipment selection), T (basic air distribution) and H (heat pumps).
ACCA Manual J is
primarily a load calculation manual. The first six sections of ACCA manual J
outline a simple, accurate procedure which can be used to estimate the heat
loss and heat gain for conventional residential structures. Residential heating
and cooling systems must be selected and designed to provide comfort conditions
in all occupied spaces regardless of season. Temperature, humidity, air
movement and ventilation must be controlled by the system. In addition, the
system must perform these functions at maximum efficiency in order to minimize
energy consumption.
The load calculation
is the basis for the system design. Loads must be analyzed if the furnace,
condensing unit, fans, coils, ducts, and air terminals are to be sized
correctly. Comfort, efficiency and reliability are closely related to correct
sizing and selection of equipment.
A load calculation
must be made for each room so that the room cooling and heating requirements
can be determined. This information is needed for terminal selection, fan and
duct sizing. A load calculation must be made for the entire structure in order
to properly size the heating and cooling equipment.
ACCA Manual S
ACCA Manual S is a
comprehensive guide for selecting and sizing residential heating and cooling
equipment. ACCA Manual S documents the procedures that should be used to select
and size residential cooling equipment, furnaces and heat pumps. These
procedures emphasize the importance of using performance data that documents
the sensible, latent or heating capacity for a wide variety of operating
conditions. This manual also suggests sizing strategies for all types of
cooling and heating equipment and it discusses the nuances of the presentation
formats that are used by equipment manufactures.
All readers are
encouraged to study sections 1 and 8 of ACCA Manual S. Section 1 is a
prerequisite because it provides and considerations that affect equipment
selection. Section 8 is useful because it explains why certification ratings
should not be used for selecting equipment.
For More Information
If you have any
questions or would like order information please contact:
Air Conditioning Contractors of
America
1712 New Hampshire Avenue, N.W.
Washington, D.C. 20009
Phone: 202/483-9370 w fax:
202/558-1217
Software
Right Suite Residential for
Windows
Wrightsoft Corporation
394 Lowell Street
Lexington,
MA 02173
(800)
225-8697
Fact Sheet Source
The information provided in this
fact sheet was compiled by ConSol, Inc. for inclusion into the Builder’s Resource
Guide for Energy Efficiency.