Page 6 - HVAC Pump Handbook

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Source: HVAC Pump Handbook

Chapter
1

Digital Electronics

and HVAC Pumps

1.1 Introduction
The emergence of digital electronics has had a tremendous impact on in-
dustrial societies throughout the world. In the heating, ventilating, and
air-conditioning (HVAC) industry, the development of digital electronics
has brought an end to the use of many mechanical devices; typical of
this is the diminished use of mechanical controls for HVAC air and
water systems. Today’s digital control systems, with built-in intelligence,
more accurately evaluate water and system conditions and adjust pump
operation to meet the desired water flow and pressure conditions.
Drafting boards and drafting machines have all but disappeared from
the design rooms of heating, ventilating, and air-conditioning engineers
and have been replaced by computer-aided drafting (CAD) systems.
Tedious manual calculations are being done more quickly and accurately
by computer programs developed for specific design applications. All
this has left more time for creative engineering on the part of designers
to the benefit of the client.

1.2 Computer-Aided Calculation of HVAC
Loads and Pipe Friction
The entire design process for today’s water systems, from initial design
to final commissioning, has been simplified and improved as a result of
the new, sophisticated computer programs. One of the most capable
programs for sizing and analyzing flow in fluid systems is the piping
systems analysis program developed by APEC, Inc. (Automated
Procedures for Engineering Consultants), headquartered in Dayton,

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