Most engineers probably feel they are safely code compliant with their waterside economizers
if their system is configured per Steve Taylor's June column:1 as an integrated economizer
with the heat exchanger in series with, and upstream of, the chillers, if their cooling tower is intelligently selected for their peak load condition, and if they provide the appropriate controls to initiate economizer
mode during the appropriate exterior conditions.
high-limit controls and why enthalpy economizers
and energy recovery systems can be useful for reducing energy requirements associated with the conditioning of outdoor air required for ventilation, and may also be able to provide free cooling under some conditions.
Sounds impressive, but do these economizers
cool data centers by bringing outside air into a building and distributing it to servers.
In typical applications of integrated (7) waterside economizers
for data centers, the return chilled water is precooled by the tower's condenser water, reducing the load on the chiller.
"Waterside and airside economizers
, design considerations for data center facilities." ASHRAE Transactions 116(1).
* All cooling AHUs have outdoor air economizers
whose performance is enhanced by the relatively warm 63[degrees]F [17[degrees]C] supply air temperature, which reduces mechanical cooling operation by more than 2,000 hours per year in this climate compared to overhead systems supplying 55[degrees]F [13[degrees]C].
30% overage on lighting due to control sensor failure +6.8% Lighting overage's effect on HVAC +1.6% Dirty AHU filters +4.1% Variable speed fans running constantly +8.4% Variable flow pumps running at full speed +10.6% Fouled cooling tower +1.3% Fouled chiller tubes +2.2 Poor refrigerant charge +3.7% Other factors in the analysis are inefficient humidity and temperature setpoints and setbacks as well as ventilation malfunctions (economizers
, outside air and C02 sensors).