APPENDIX A (Continued)
Energy Efficient Systems. Design factors such as reliability can
have priority over energy efficiency. An energy saving feature that is
unstable or not maintained may fail and actually consume more energy than a
simpler stable HVAC system. Select the least complicated energy efficient
system for the application. Energy efficient devices shall be specified when
possible if they are life cycle cost effective.
Economizer Cycle Systems. Contact the individual NAVFACENGCOM EFD
or EFA for exact guidance on the use of economizer cycles. In the absence of
immediate guidance, systems larger than 10 tons shall be designed to use
maximum outside air for cooling whenever the outdoor dry bulb temperature is
lower than 60 degrees F more than 3000 hours per year. Operation shall be
limited by an outdoor air dry bulb sensor. Do not use economizer cycle
systems in humid climates.
Multiple Parallel Equipment Systems. Multiple parallel equipment
handlers, etc., provide superior operating efficiency, added reliability, and
the operating capacity required at design conditions. Use multiple equipment
systems when energy savings will offset higher first costs.