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52017 Calculation procedures (:pen: Long wave radiation (Density heat flow…
52017 Calculation procedures
Assumptions
Air temp: Uniform
Surfaces: Isothermal
Air spaces: air layer btw parallel surfaces
.
Heat conduction: one-dimensional
[..] to Ground: Equivalent [..]"
Thermal bridges: thermally coupled to air temps
.
Heat storage (therm bridge): Neglected
Heat storage (glazed): neglected
Absorbed radiation (glazed): source term
Formulas :pen:
Operative temp
Internal mean radiant temp
Sensible heat balance equation
( '-> only convective fraction)
Internal surface temp
Temp surfaces of solid layers
Temp surface of air layer
Temp external surface
Zone thermal balance
Heat flow rate
related to:
Internal/External surface temp
time-dependent
Solution:
Internal air temp
:pen:
Heat conduction of building components
Convective heat transfer
surface
unventilated air layer
ventilated layer
:pen: Thermal bridges
Heat flow rate
:pen: Short wave radiation
Density of external/internal/glazing
heat flow rate
Sunlit factor
Direct/Diffuse
heat flow rate
Solar to air
heat flow rate
Solar to heat factor
Solar loss factor
:pen: Long wave radiation
Density heat flow rate
from external/internal surface
Heat transfer coefficient
Density heat flow rate
element-->sky
Radiosity
= (emitted - reflected) density
heat flow rate
Density h.f.r. of air layers
Internal sources
Lighting
Equipment
People
Heat Flow Rate
convective
radiative
uniform distribution on surfaces
Loads
:pen: Ventilation
sensible hfr
latent hfr
Sensible H/C=
convective + long-wave radiative
:pen:
Latent heat balance equation
Latent (de-)humid hfr =
§ moisture load