— kW
COOLING LOAD
Cooling load & AC sizing
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Preliminary single-room estimate. Separate sensible and latent loads before selecting AC capacity.
Room inputs
01 · Room & design conditions
m²
m
°C
%
Relative humidity of the room air.
°C
%
Relative humidity of the outdoor air.
kPa
02 · Envelope & glazing
m²
W/m²K
Lower values mean better insulation. Unit: W/m²K.
K
m²
W/m²K
Lower values mean better insulation. Unit: W/m²K.
K
m²
W/m²K
Lower values mean better insulation. Unit: W/m²K.
W/m²
Range 0–1. A value of 0.5 means 50% of incident solar heat enters through the glazing.
Range 0–1: 1 means unshaded, 0 means fully shaded in this estimate.
03 · People & equipment
people
W
W
W/m²
W
A value of 0.8 means 80% of equipment heat gain occurs simultaneously.
04 · Outdoor air & other gains
m³/h
1/h
A value of 0.3 means infiltration per hour equals 30% of room volume; excludes outdoor-air ventilation.
W
W
05 · AC selection assumptions
%
units
A value of 0.75 means 75% temperature cooling and 25% dehumidification. Use equipment data.
A value of 0.9 means 90% of nameplate capacity at design conditions. Use equipment selection data.
Defaults are examples. Exclude outdoor air conditioned by a separate system. ACH is additional infiltration; avoid double counting.
TARGET COOLING CAPACITYPreliminary estimate
—
—
Room load before allowance—Sensible / total load ratio—Floor load density—
— kW
— m³/h
AC capacity suggestion
Cooling capacity is not electrical input. Verify total, sensible and latent capacities against equipment performance at actual indoor/outdoor conditions.
Method & limitations ＋
Steady-state heat-gain estimate, not hourly HB/RTS. Walls/roof: U·A·(Tout−Tin+ΔTsolar); glazing: U·A·ΔT + A·I·SHGC·Fshade. Solar equivalent rise is user-defined and is not derived from orientation, weather or design hour.
People: count × sensible/latent gain per person. Lighting: area × W/m². Equipment: heat gain × use factor. Outdoor-air total load uses dry-air mass flow × enthalpy difference; sensible load uses heat capacity at indoor humidity ratio, with latent load as the remainder. Cooler/drier outdoor air can produce negative components; aggregate sensible and latent loads are each floored at zero for sizing.
The allowance applies to both sensible and latent loads. The smallest reference BTU/h size meeting total, sensible and latent requirements is selected using unit count, assumed SHR and capacity factor. This does not replace manufacturer selection data or peak-load calculations with weather, thermal storage, solar orientation, thermal bridges and schedules. Floor/adjacent-zone, fan/duct and recovery effects are not calculated; use other gains as appropriate.
ASHRAE — Cooling load calculations