Description Usage Arguments Details Author(s) References See Also Examples

Estimates heat transfer by convective heat exchange, using the heat transfer coefficient estimate, surface temperature, and air temperature. Positive value = heat gain from air to object. Negative value = heat loss from object to air.

1 2 |

`Ts` |
Surface temperature (degrees celsius). Default value is 30. |

`Ta` |
Air temperature (degrees celsius). Default value is 20. |

`V` |
Air velocity (m/s). Default value is 1. |

`L` |
Characteristic dimension (m) of object. Usually the vertical dimension (i.e. height). Default value is 0.1. |

`c` |
coefficient used in forced convection (see Blaxter, 1986, default value is 0.24). see forcedparameters() for details. |

`n` |
coefficient used in forced convection (see Blaxter, 1986, default value is 0.6). see forcedparameters() for details. |

`a` |
coefficient used in free convection (see Gates, 2003. default value is 1). see freeparameters() for details. |

`b` |
coefficient used in free convection (0.58 upright cylinder, 0.48 flat cylinder, default value is 0.58). see freeparameters() for details. |

`m` |
coefficient used in free convection (0.25 laminar flow, default value is 0.25). see freeparameters() for details. |

`type` |
"forced" or "free" - to calculate convection coefficient for either forced or free convection. Default value is "forced". |

`shape` |
"sphere", "hplate", "vplate", "hcylinder", "vcylinder" to denote shape and orientation. h=horizontal, v=vertical. Default shape is "hcylinder" |

Estimates an area specific rate of heat transfer (W/m2), where a negative value depicts heat loss from surface to air, while positive value depicts heat gain from air to surface. Uses the gradient in temperature (Ta minus Ts) multiplied by a convection coefficient to estimate heat transfer from a surface. Designed for estimating steady state heat exchange from animal surfaces using thermal images.

Glenn J Tattersall

Blaxter, 1986. Energy metabolism in animals and man. Cambridge University Press, Cambridge, UK, 340 pp.

`hconv`

,
`forcedparameters`

,
`freeparameters`

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 | ```
## The function is currently defined as
function (Ts = 30, Ta = 20, V = 1, L = 0.1, c = NULL, n = NULL, a=NULL,
b = NULL, m = NULL, type = "forced", shape="hcylinder")
{
qconv <- (Ta - Ts) * hconv(Ta = 20, V = 1, L = 0.1, c = NULL, n = NULL, a=NULL,
b = NULL, m = NULL, type = "forced", shape="hcylinder")
qconv
}
# Example:
Ts<-30
Ta<-20
V<-1
L<-0.1
type="forced"
shape="hcylinder"
qconv(Ts=Ts, Ta=Ta, V=V, L=L, type=type, shape=shape)
qconv(Ts=Ts, Ta=Ta, V=V, L=L, type=type, shape="sphere")
# For detailed examples and explanations, see:
# https://github.com/gtatters/Thermimage/blob/master/HeatTransferCalculations.md
``` |

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