Retrotec USACE - Manual (Page 405)

Appendix L L5
2.2.28 In humid climates, supply air with a temperature above the dew point to prevent con-
densation on cold surfaces.
2.2.29 Insulate fan-coil units and avoid their installation in nonconditioned spaces.
2.2.30 Prevent chilled water or condenser water fl owing through the offl ine chiller. Chillers
can be isolated by turning off pumps and closing valves.
2.2.31 Conduct seasonal surfaces cleaning of the heat exchangers in the evaporator and con-
densers.
2.2.32 Balance water fl ow in the chilled water system.
2.2.33 Use variable chilled water temperature based on the required cooling load.
2.2.34 Use water-cooled chillers instead of air-cooled units.
2.2.35 Use smaller, more effi cient chillers that can operate during low cooling demand times
of the year when possible.
2.2.36 Use variable frequency drives (VFDs) for the primary chilled water pumps above 5 HP
(3.7 kW) (Appendix J).
2.2.37 Use variable frequency drives (VFDs) for the condenser water pumps (Appendix J).
2.2.38 Apply cooling load–based optimization strategies (Appendix J).
2.2.39 Use high effi ciency dehumidifi cation systems based on either dedicated outdoor air sys-
tems (DOAS) or variable air volume (VAV).
2.2.40 Install water source heat pumps (WSHPs) to augment the capacity of the hot water
boiler and to reduce the cooling load on the existing chiller systems when heat is re-
quired (Appendix J).
2.3 HVAC Distribution Systems
2.3.1 Use high-effi ciency fans and pumps; replace or trimming impellers of existing ones.
2.3.2 Install air cleaners in HVAC system.
2.3.3 Insulate HVAC ducts.
2.3.4 Insulate HVAC system pipes.
2.3.5 Check for air leaks in HVAC system.
2.3.6 Clean air fi lters in ducts.
2.3.7 Repair (seal) supply and exhaust ducts and piping leaks. Up to 20% of conditioned air
can be lost during supply duct run.
2.3.8 Check for damper leakage; ensure tight seals.
2.3.9 Rebalance ducting systems.
2.3.10 Rebalance piping systems.
2.3.10 Select cooling coils with a face velocity of 300–350 fpm (1.5–1.75 m/s) range to reduce
the air pressure drop across the cooling coil, and increase the chilled water system tem-
perature differential across the system.
2.3.11 Check fan belts.
2.3.12 Replace dirty fi lters.
2.4 Refrigeration
2.4.1 Check the refrigerant charge and add when needed.