Consulting-Specifying Engineer - September 2008 - (Page 38)

Expansion tank Air-cooled chiller Chemical feeder Suction diffuser (typical) Pump CHP2 Pump CHP1 Training AHU Rooftop AHU Ice storage Ice storage Figure 2 My version (founded on Chuck’s principles) of the Pacific Energy Center ice storage system. This drawing focuses on the chilled glycol loop. I have separate drawings for the air-handling loads served by the loop. chilled water system from the other side of the chiller where there was no automatic isolation valve, and, as I could now see after the explanation, no need for one. Al Black, another mentor, put it this way on a different occasion, “The ‘goesintas’ gotta equal the ‘goesoutas.’” In other words, conservation of mass dictated that if no mass moved into the system, no mass would move out of it. Phil also mentioned a good preventive maintenance check would be some sort of test to verify the control interlocks that commanded the valve to the position that isolated the chiller from the hot water system when the system was in heating mode. He also pointed out another important test with energy-efficiency implications. Specifically, a test to verify that the three-way valve was not leaking and that the heat exchanger was shut down when the chiller was in operation would ensure that simultaneous heating and cooling were not occurring. Of course, if everything was working properly, the design of the control system would prevent this problem. But, having been a practicing airframe and power plant mechanic, I knew that wear and tear could take its toll on the intent behind a design, thus the need for maintenance in general, and preventive maintenance in particular. Phil left it to me to work out the tests but made sure I felt comfortable visiting his office anytime if I had questions. Phil also took me on-site later in the week as he started the balancing process. Once we were there, he helped me start to correlate the diagram I had developed from the drawings with the actual components in the field, and introduced me to pump tests and pump curves. Phil also introduced me to Ben, a control technician who worked for the control company. Phil knew I would need to understand how the control system worked if I was going to write the manuals, tests, and checklists for the preventive maintenance program. He was right; Ben was invaluable. Ben allowed me to “assist” him as he checked out the controls, which was my first exposure to electronic control systems. I use “assist” lightly because I suspect it took Ben about twice as long to do his job that day because I tagged along asking question after question about how things worked and what he was doing. There were occasional grumbles from Ben, but he always gave me at least a cursory answer. These answers gave me leads on where to go next to understand things and do my job. Early experiences: the lessons In those first few experiences on the job, I learned a number of important lessons. The technical lessons were immediately obvious. A steam converter is a steam heat exchanger. (In my defense, I should point 38 Consulting-Specifying Engineer • SEPTEMBER 2008

Table of Contents Feed for the Digital Edition of Consulting-Specifying Engineer - September 2008

Consulting-Specifying Engineer - September 2008 Contents Viewpoint Letters News M/E�Roundtable Selecting Appropriate Egress Strategies Commissioning On-Site Electrical Systems Mentoring Control Engineers and Technicians Casting Call for Cx Case Study New Products Equipment Lifecycles Advertiser Index Green Space

Consulting-Specifying Engineer - September 2008

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