In order to meet the increased expectations of building occupants, designers must be aware of the conflicts between first cost economics, occupant productivity and life cycle costs. Buildings that do not meet the needs of the occupants often result in expensive redesign or worse, result in lawsuits against all parties involved. First, we need to understand the rules:

1. LEED: 2009 is out, and many are not aware of some significant changes that have resulted in air distribution, IAQ and Comfort.
2. Thermal Comfort: Determining optimum occupant comfort strategies. ASHRAE Standard 55 has been revised.
3. Acoustics: Accurately predicting end use environments. A new classroom acoustical requirement needs to be understood.
4. IAQ: The changing face of ASHRAE Standard 62.1, and upcoming developments.

With the goal of saving energy over the 90.1 baseline (Overhead VAV), many architects are challenging the mechanical engineer to come up with alternate systems that will meet this goal.  Displacement Ventilation (DV), Underfloor Air Distribution (UFAD) and Chilled Beams all have a potential to save energy, and meet these needs.

I will briefly cover pros and cons of all 4 methods of air delivery:

• Overhead air distribution
• DV ( Displacement Ventilation)
• Underfloor Air Distribution (UFAD)
• Chilled Beams and the DOAS Fan Box

While much has been said about saving energy, little is said of the downside if the savings strategy reduces occupant productivity. The average salary in any office is 100 times greater than the full cost of heating and cooling that space. Strategies that add to the first, renovation, or operating cost of a space have to be weighed against the potential for reduced productivity when calculating the time to payback.

We aren’t doing a very good job, it seems. BOMA continues to report that the #1 reason for tenants not renewing the lease is “occupant dissatisfaction with the thermal environment”. ASHRAE Standard 55 describes the conditions that will satisfy a majority of the occupants. It is often referenced in code, and many LEED projects have been awarded a point for compliance, at the design stage, of course.

In practice however, we find that systems don’t operate at design, or even as designed. We will discuss the issues related to maintaining comfortable conditions.at all loads, and discuss the benefits of ventilation and economizer operations.      

The basic physics of air distribution must be fully understood before one can properly select components for a project. Air Distribution is not being taught at many Engineering schools, and young engineers are often unwilling to admit how little they actually know.  Senior engineers need to be brought up to speed on the latest understandings of air diffusion component selections.  This lecture will cover:

• Understanding Terminology
• ADPI (Air Diffusion Performance Index)
• Proper Diffuser Selection
• Common Product Groups
  • Well Mixed (Inductive) Air Distribution
  • Non Inductive Air Distribution

With the large number of VAV terminals available, including ECM motors for series and parallel boxes, we are getting a number of questions regarding the proper selection and interpretation of VAV terminal specifications. I will discuss:

• Proper engineering specifications and designs for this broad product range,
• Updates on the latest rules and knowledge regarding VAV box type, linings, accessories and air flow limitations.
• The latest Industry understandings of the proper application of overhead heat to meet the Standard 62.1, Standard 55 and LEED V4
• The results from the A&M Study on Series/Parallel and ECM/PSC motors.
• The application of DOAS through dual duct. Dual inlet fan boxes and using a sensible cooling coil on a Series fan powered terminal.
• The impact of the new rules on reporting Discharge sound power, which results in higher calculated sound power values in the critical low frequencies.

Highlighting developments from 1973 until the present, I will present technical achievements, Standards Updates, and ASHRAE Research projects that all converged into an understanding and technical validation of modern approaches to comfort, energy, and building designs. The idea for the talk comes from our recent Presidential Member’s theme, and caused me to reflect on a number of technical paths that I have been involved in pursuing throughout my ASHRAE career. 

   The subject was recently discussed in my article Highlighted in the August 2016 ASHRAE Insights.