Figure 2: Poor solar orientation. 2. The outdoor airflow rate required to meet the ventilation requirements of Section 6.2 of ASHRAE Standard 62.1 for the zone (this only applies to 100% outside airstreams that don’t mix with additional heated air); 3. Any higher rate that can be demonstrated, to the satisfaction of the authority having jurisdiction, to reduce overall system annual energy usage by offsetting reheat/recool energy losses through a reduction in outdoor air intake for the system; 4. The airflow rate required to comply with applicable codes or accreditation Standards (e.g., pressure relationships or minimum air change rates); 5. Laboratory exhaust systems complying with 6.5.7.2; which requires buildings with lab exhaust systems totaling over 5,000 cfm (2360 L/s) to comply with one of three criteria that relate to VAV, energy recovery, and non- or semi-treated makeup air; and 6. Zones where at least 75% of the energy for reheating or for providing warm air in mixing systems is provided from a site-recovered (including condenser heat as described below) or site-solar energy source. In Exception 1, an alternate was added for dual minimums on VAV boxes. This permits reheating up to 50% of the peak design flow rate if the minimum flow rate in deadband (no reheat) is 20% or less of the peak design flow rate. The fourth exception is intended primarily for hospitals and laboratories that are mandated to provide ventilation rates that would otherwise make it impossible August 2012 www.info.hotims.com/41642-93 42 ASHRAE Journal