Over the years of designing and building HVAC infrastructure, I’ve been fortunate to be able to complete the projects via integrated project delivery (IPD) and design-build (D-B), in addition to design-bid-build (DBB) and construction management (CM).

Hydraulic modeling is seldom used in the day-to-day design of closed-loop or open-loop heating and cooling systems.

Years after an HVAC engineer starts to design closed-loop water systems and then progressively moves up the ladder of engineering success, he can forget and/or overlook many of the issues, concerns, details, opportunities, etc. associated with engineering these systems.

With last month’s publication, Engineered Systems magazine and I completed the 25th year of publishing this column.

How often does an existing open condenser water system, or some other type of open water system, get reused as part of a building renovation project and/or mechanical system upgrade

How often does an existing closed loop hot water heating or chilled water cooling system get reused as part of a building renovation project, and/or used to expand the area served by the system coverage to provide additional heating or air conditioning?

This month, the focus is on high-performance health care, and so it got me thinking about IAQ and infection control (IC) within hospi-tals.

This past August, I wrote in this column about the opportunity to invest in a niche business providing temporary HVAC design and construction administration.

How often has an AHU or system been reused as part of a building renovation project and/or to expand the area served by the associated unit to provide additional air conditioning or heating?

This past May I wrote in the Back2Basics column about the design intent of a small city school system that chose to invest in an annual contract for a temporary air-cooled chiller for special events and emergency crisis shelter center.