Monday, 27 June 2016: 8:00 AM-9:30 AM
Fundamentals and Applications
Chair:
Glenn Friedman, P.E., Taylor Engineering
Technical Committee: 04.01 Load Calculation Data and Procedures
No one can afford the risk of getting load calculations wrong. If load calculations are too fat you lose the job, and if too skinny you have a liability you don’t want. This session presents important information about residential loads calculations including their science, the art, their code requirements and their state of the art. The session also presents information about residential load calculation methods in wide use today, explores the impact of technology on how these methods are applied and speculates on the techniques that may underlie “next generation” procedures.
1 Code Requirements for Residential Load Calculations and Manual J
 |
Luis Escobar |
The International Code Council (ICC) and International Association of Plumbing and Mechanical Officials (IAPMO) both promulgate mechanical codes that have required residential load calculations for years. Manual J is the only ANSI-recognized consensus standard for residential load calcs, and is referenced specifically by both code organizations. This portion of the presentation will review the specific code requirements in the International Residential Code (IRC) and the Uniform Mechanical Code (UMC), and then go on to explain the CLTD method for residential load calculations contained in Manual J.
2 Residential Load Calculations Using the Heat Balance Method
 |
Charles S. Barnaby, CSB Consulting |
Most residential cooling load calculations rely on CLTD methods that use single-point calculations for at most a few design days. CLTD procedures make implicit assumptions about the time profiles of heat gains and the moderation of cooling loads by building thermal mass. The heat balance method has the advantage of first-principles 24 hour calculations – gains are combined following their actual profiles. It handles subtle interactions that occur in low energy houses and evaluates the effect of temperature swing that is typical of residential systems. The presentation describes the heat balance method and shows comparisons to CLTD results.
3 How New Technologies Are Changing the Way HVAC Residential Load Calcs Are Performed
 |
Stephen Roth, P.E., Carmel Software Corp. |
Stephen discusses how HVAC technicians are using mobile devices to perform residential HVAC load calculations. So much processing power is now packed into mobile devices that complex software such as this that once could only run on desktop computers can easily run on these mobile devices. HVAC technicians have quickly embraced these devices to perform all manner of field-based work. Some of the benefits include: Saving time by entering all information onsite and emailing required reports to code officials and clients and calculating more accurate HVAC cooling and heating loads so that equipment is sized correctly.