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? It happens probably every day somewhere, and yet I can’t say I have ever seen a quality control engineering checklist to standardize the process, to maximize the reuse of the pipe distribution and to reuse or replace existing pump(s). Hindsight is always 20/20, so why isn’t there a checklist to avoid past errors and omissions, as well as to improve on system design from site-specific lessons learned?
To start, the design engineer should document the existing basis of design and review it with the existing facility personnel to get a sign-off on the original criteria and design assumptions. As the new design of the closed-loop system is being finalized, the engineer should meet with the facility personnel to get sign-off that the new basis of design is adequately addressing past deficiencies, proposed energy conservation measures, and O&M design intent.