Givoni-Milne strategy overlay

comfort_strategy_givoni() stores the fixed inputs used by geom_comfort_givoni(). By default it anchors the comfort zone to the Givoni/Milne 1979 bounds: 20 to 25.5 degrees C dry-bulb temperature and 20% to 80% relative humidity with the hot-humid corner clipped. The adaptive variant shifts the base comfort zone from a mean outdoor temperature. Strategy zones are drawn in dry-bulb/relative-humidity space before conversion to humidity ratio.

Usage

comfort_strategy_givoni(
  mean_outdoor = NULL,
  units = c("SI", "IP"),
  variant = c("fixed", "adaptive"),
  tdb_range = NULL,
  relhum_range = c(20, 80)
)

Arguments

mean_outdoor

Mean or running-mean outdoor temperature used when variant = "adaptive". It is ignored when variant = "fixed" and can be NULL for that variant.

units

Unit system for mean_outdoor, "SI" or "IP".

variant

Givoni-Milne strategy variant. "fixed" uses the fixed 1979 comfort anchor; "adaptive" shifts the comfort anchor from mean_outdoor.

tdb_range

Optional dry-bulb comfort-anchor range used when variant = "fixed". Values use units. When NULL, the fixed variant uses 20 to 25.5 degrees C.

relhum_range

Relative-humidity comfort-anchor range in percent.

Value

A Givoni-Milne comfort strategy object.

Details

This overlay is a climate-screening and design-strategy aid. It should not be interpreted as a comfort-standard compliance method or as a substitute for building energy/thermal simulation. In particular, the high-mass and night ventilation regions indicate potential strategy ranges; using them to count comfort hours requires daily temperature profiles, nighttime conditions, and building assumptions that are outside this layer.

References

Milne M, Givoni B. Architectural design based on climate. In: Watson D, ed. Energy Conservation Through Building Design. McGraw-Hill; 1979:96-113.

Givoni B. Comfort, climate analysis and building design guidelines. Energy and Buildings. 1992;18(1):11-23. doi:10.1016/0378-7788(92)90047-K

Herb S, Wolk S, Reinhart C. Beyond the bioclimatic chart: An automated simulation-based method for the assessment of natural ventilation and passive design potential. Building and Environment, 269, 112362. doi:10.1016/j.buildenv.2024.112362

Examples

# Create the fixed Givoni/Milne 1979 strategy.
comfort_strategy_givoni()
#> $mean_outdoor
#> [1] NA
#> 
#> $units
#> [1] "SI"
#> 
#> $variant
#> [1] "fixed"
#> 
#> $tdb_range
#> NULL
#> 
#> $relhum_range
#> [1] 20 80
#> 
#> attr(,"class")
#> [1] "PsyComfortGivoniStrategy" "list"                    

# Create an adaptive Givoni-Milne strategy for a warm outdoor mean.
comfort_strategy_givoni(variant = "adaptive", mean_outdoor = 22)
#> $mean_outdoor
#> [1] 22
#> 
#> $units
#> [1] "SI"
#> 
#> $variant
#> [1] "adaptive"
#> 
#> $tdb_range
#> NULL
#> 
#> $relhum_range
#> [1] 20 80
#> 
#> attr(,"class")
#> [1] "PsyComfortGivoniStrategy" "list"                    

# Or provide project-specific comfort anchor ranges.
comfort_strategy_givoni(
    tdb_range = c(22, 27),
    relhum_range = c(30, 70)
)
#> $mean_outdoor
#> [1] NA
#> 
#> $units
#> [1] "SI"
#> 
#> $variant
#> [1] "fixed"
#> 
#> $tdb_range
#> [1] 22 27
#> 
#> $relhum_range
#> [1] 30 70
#> 
#> attr(,"class")
#> [1] "PsyComfortGivoniStrategy" "list"                    

# Draw the Givoni strategy overlay for that outdoor mean.
ggpsychro(tdb_lim = c(5, 45), hum_lim = c(0, 30)) +
    geom_comfort_givoni(
        strategy = comfort_strategy_givoni(
            variant = "adaptive",
            mean_outdoor = 22
        ),
        labels = FALSE
    )