Changing Climate…Making Decisions Regarding Design Conditions
Last summer was probably the most humid that I’ve experienced in SoCal in the past 25 years. I’m not talking about peak humidity on the worst day; that happens every year, usually right after a summer rain shower (despite what the famous Albert Hammond song suggests, summer showers are not unheard of here). Last summer was remarkable because of the duration of what we would consider to be muggy weather. El Nino conditions mean warmer ocean surface water, and that translates directly into more humid conditions in the LA basin. We started the summer more humid than usual and carried that through much of the fall. Condensate drains were tested. Cooling towers, fluid coolers and evaporative condensers experienced “worst case” capacity reductions. Outside air cooling load continued at a sustained peak. And evaporative coolers? In many cases they earned their nickname (“Swamp Coolers”). Decisions regarding design conditions are always somewhat subjective, and it is important to recognize this not only when designing new systems, but also when replacing old equipment. A lot of equipment that was originally installed 20-30 years ago was sized rather optimistically from the perspective of our experience last summer.
If you would like to know more, this link will take you to a relevant SoCal ASHRAE chapter newsletter article: http://ashrae-socal.org/SolAir-September-2015-Final-draft2.pdf