ASHRAE Standard 183
HVAKR implements ANSI/ASHRAE/ACCA Standard 183 - Peak Cooling and Heating Load Calculations in Buildings Except Low-Rise Residential Buildings.
Standard Overview
Section titled “Standard Overview”Purpose
Section titled “Purpose”Standard 183 establishes:
- Minimum requirements for load calculations
- Acceptable calculation methods
- Required documentation
Applies to:
- Commercial buildings
- Institutional buildings
- Industrial buildings
- High-rise residential
Calculation Methods
Section titled “Calculation Methods”Cooling Loads
Section titled “Cooling Loads”Standard 183 approves several methods:
- Radiant Time Series (RTS)
- Heat Balance (HB)
- Transfer Function Method (TFM)
HVAKR uses the Radiant Time Series (RTS) method.
Heating Loads
Section titled “Heating Loads”Steady-state calculation:
- Based on design conditions
- No solar or internal credits
- Conservative for equipment sizing
Radiant Time Series Method
Section titled “Radiant Time Series Method”Overview
Section titled “Overview”RTS accounts for:
- Thermal storage in building mass
- Time delay of heat gains
- 24-hour load profiles
Process
Section titled “Process”- Calculate instantaneous heat gains
- Split into convective and radiant portions
- Convert radiant to cooling load using RTFs
- Sum for total load
Radiant Time Factors
Section titled “Radiant Time Factors”Pre-calculated factors for:
- Lightweight construction
- Medium-weight construction
- Heavyweight construction
Required Inputs
Section titled “Required Inputs”Weather Data
Section titled “Weather Data”Per Standard 183:
- Design temperatures from ASHRAE
- Solar data for the location
- Humidity conditions
Building Data
Section titled “Building Data”Required information:
- Envelope U-values
- Window SHGC
- Internal loads
- Schedules
Occupancy
Section titled “Occupancy”Occupancy characteristics:
- Number of people
- Activity levels
- Schedules
Design Conditions
Section titled “Design Conditions”Outdoor Conditions
Section titled “Outdoor Conditions”ASHRAE design data:
- 0.4% or 1.0% cooling design
- 99.6% or 99% heating design
- Coincident humidity
Indoor Conditions
Section titled “Indoor Conditions”Typical setpoints:
- Cooling: 75°F, 50% RH
- Heating: 70°F
Load Components
Section titled “Load Components”Required Components
Section titled “Required Components”Standard 183 requires accounting for:
- Transmission through envelope
- Solar radiation
- Internal gains (people, equipment, lighting)
- Ventilation
- Infiltration
Component Breakdown
Section titled “Component Breakdown”HVAKR provides detailed breakdown for verification.
Documentation
Section titled “Documentation”Required Documentation
Section titled “Required Documentation”Standard 183 requires:
- Input data listing
- Calculation method identification
- Results summary
- Assumptions
HVAKR Reports
Section titled “HVAKR Reports”HVAKR generates compliant documentation:
- Loads Summary report
- Component breakdown
- Design conditions
HVAKR Implementation
Section titled “HVAKR Implementation”Automatic Compliance
Section titled “Automatic Compliance”HVAKR automatically:
- Uses approved RTS method
- Applies ASHRAE weather data
- Calculates all required components
- Documents assumptions
Verification
Section titled “Verification”Check your calculations:
- Review load components
- Verify design conditions
- Compare to benchmarks