HVAC Design Engineering Basic

A: The aim is a quick volume-based flow: 100×3 gives 300 m³, multiplied by 10 ACH and divided by 3600. Option B jumps to a floor-area heuristic that doesn't match the stated ACH. Option C folds in time-of-use, which doesn't change instantaneous flow. Option D confuses supply sizing with pressure balancing allowances.

A: The safeguard achieves fire compartmentation during a power failure, not maintaining day-to-day airflow. Option B is exactly what a closed damper limits. Option C assumes the damper remains open, which contradicts the fail-safe action. Option D is mitigated by closure, not left exposed.

A: The selection aims to control low-temperature aqueous corrosion where oxygen sneaks in during top-ups. Option B needs hot, sulfur-bearing service. Option C is tied to austenitic stainless steels, not galvanized carbon steel. Option D is more associated with lukewarm open systems and biofilms.

A: The goal is total load, so you read inlet and outlet enthalpy and multiply by mass flow. Option B ignores latent removal entirely. Option C double-counts by forcing sensible math onto a dehumidifying process. Option D introduces a coil performance factor without any data to support it.

A: The outcome sought is reconciling measured performance with real hardware, starting from the fan and system curve. Option B masks the root cause and risks noise and motor issues. Option C ignores the regulatory threshold. Option D increases pressure drop and worsens the shortfall.

A: The estimate targets a quick sensible-plus-latent figure consistent with seated office work. Option B assumes metabolic rates far above reality. Option C drops latent heat without justification. Option D applies diversity that belongs to coincident peak analysis, not a single-zone check.

A: The protection aim is maintaining minimum outdoor air, which fails quietly when sensing lies low. Option B needs a fan or duct protection device, not a box sensor. Option C mixes air-side sensing with water-side control. Option D involves a different control layer entirely.

A: The intent is resisting chloride-driven corrosion while keeping thermal performance reasonable. Option B sacrifices longevity in salt air. Option C adds mass and still corrodes at cut edges. Option D mixes premium tubing with vulnerable fin material, so the weak link remains.

A: The goal is reconciling real-world measurements, acknowledging duct leakage, traverse error, and hood losses. Option B assumes instrument hierarchy without evidence. Option C ignores diffuser placement and hood fit issues. Option D violates mass conservation outright.