Broad eaves, awnings, and other shading devices also reduce solar gain. HOK s Mendler took advantage of the existing tree canopy to shade the western facade of the EPA Campus. This was one solution that was absolutely free, she says. A decade or two ago, it was not uncommon to see lighting power densities of two to four watts per square foot. Nearly all the heat generated by lights and other internal loads must be removed by the building s cooling system.
Few engineers are willing to discount the connected load in their cooling calculations.
Defining a low target for lighting power density and making sure the engineer uses that value for cooling-load calculations will make a significant dent in cooling tonnage. There s a fear and trust issue at work here. If there s not enough cooling, the mechanical engineer is the first to take the blame. So they go back to their computer and enter two or three watts. We see it all the time.