Infiltration load: 300 Btu/h sensible 1,200 Btu/h latent.Envelope load (conduction): 500 Btu/h sensible.Internal loads: 17,000 Btu/h sensible 10,000 Btu/h latent.System type: Variable air volume (VAV).Space: A 1,000-sq-ft conference room with an exterior window.Indoor design target: 74☏ dry-bulb 65% RH.1% design conditions: 74.1☏ dew point 81.1☏ mean coincident dry-bulb temperatures.It is important to consider this type of scenario, as well as other part-load scenarios with potentially high outdoor or indoor latent loads, when designing HVAC systems to properly manage indoor RH, especially in warm and humid climate zones that predominate in the eastern and southern United States. No solar loads (but shall include envelope conduction and infiltration loads).Indoor sensible and latent loads at design conditions.Outdoor conditions at the dehumidification design conditions (user-stipulated at the 2%, 1%, or 0.4% conditions) dewpoint and mean coincident dry-bulb temperatures.The dehumidification design condition within the standard is to maintain a maximum indoor RH of 65% under the following: While the standard does not attempt to mandate design checks for all system operational situations, Section 5.9.1 requires the designer to address RH management of the HVAC system under a typical dehumidification design condition. One important, and often overlooked, aspect of good ventilation and HVAC system design is the control of indoor RH. Aspects governed by this section include duct and air distribution system design, air handling system design, outside-air intake proximity to exhausts and other potential contaminant sources, controls, filtration, rain entrainment and façade moisture management, and operations and maintenance, to name just some of the many important aspects covered by the standard and required for compliance. This section of the standard governs many aspects of the HVAC and building (read: architectural) systems that impact IAQ. Section 5 is an important portion of the standard that many engineers and architects often fail to fully evaluate for compliance. Appendix B, B2: Determining L Distance (for exhaust-air outlet separations).Appendix A, A1.2.2: Secondary Recirculation Air Systems.Section 6.2.6.2: Short-Term Conditions.This article will summarize and provide examples for the following less common calculations included within ASHRAE Standard 62.1-2016:
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