Save Money and Energy by Detecting Heat Losses
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This document discusses quantitative thermography and infrared radiation. It explains that infrared is emitted, reflected, transmitted, and absorbed, with the amount depending on temperature. It presents the equations of Planck's law and Stefan-Boltzman's law that describe blackbody radiation as a function of temperature and wavelength. Convection heat transfer is also discussed. The document provides examples of calculating heat loss from pipes and annual savings from insulating pipes to reduce heat loss. It concludes with questions about calculating potential annual savings from insulating pipes.
![Radiation Laws
Planck’s Law
The formula describing the spectral radiation of a perfect blackbody as a function of its
temperature and the wavelength of the emitted radiation
Wλb = 2π h c2 x 10-6 [ W/m2(µm)]
λ5 (ehc/λkT – 1)
h-=Planck’s constant
k=Boltzman’s contstant
Stefan-Boltzmann’s Law
The formula indicates the total radiation at ALL wavelengths from a perfect blackbody
W[TOTAL] = 5.67 x 10-8 T4 [W/m2]](https://image.slidesharecdn.com/conditionmonitoringpresentation-150701141306-lva1-app6892/85/Save-Money-and-Energy-by-Detecting-Heat-Losses-6-320.jpg)
![Convection
For horizontal pipes
WConvection = 1.35 x (Ts – Ta)0.25 / dop [ W/m2]
Ts = Absolute temperature of heat emitting surface
Ta = Absolute temperature of air
dop = Outside diameter of pipe/insulation](https://image.slidesharecdn.com/conditionmonitoringpresentation-150701141306-lva1-app6892/85/Save-Money-and-Energy-by-Detecting-Heat-Losses-7-320.jpg)
Save Money and Energy by Detecting Heat Losses
- 1. Quantitative Thermography Temperature and Tantrums
- 2. Infrared – What is it?
- 3. How is it emitted? E = hv Frequency of radiation, sometimes written as f giving expression E=hf. Quantum energy of a photon. H – Planck’s constant = 6.626 x 10 Joule-sec = 4.136 x 10 eV-s -34 -15
- 4. The Weird World of Infrared What is this?
- 5. Emitted (Tg) Reflected (Tr) Transmitted (Tt) The Weird World of Infrared – Part 2 AbsorbedBackground (Tb) Gas “Cloud”
- 6. Radiation Laws Planck’s Law The formula describing the spectral radiation of a perfect blackbody as a function of its temperature and the wavelength of the emitted radiation Wλb = 2π h c2 x 10-6 [ W/m2(µm)] λ5 (ehc/λkT – 1) h-=Planck’s constant k=Boltzman’s contstant Stefan-Boltzmann’s Law The formula indicates the total radiation at ALL wavelengths from a perfect blackbody W[TOTAL] = 5.67 x 10-8 T4 [W/m2]
- 7. Convection For horizontal pipes WConvection = 1.35 x (Ts – Ta)0.25 / dop [ W/m2] Ts = Absolute temperature of heat emitting surface Ta = Absolute temperature of air dop = Outside diameter of pipe/insulation
- 9. Total loss in horizontal pipework Q = length π dop (WConvection + WRadiation) = length x π dop x (1.35 x (Ts – Ta)0.25 / dop + 5.67 x 10-8 T4)
- 10. Examples
- 11. Examples
- 12. Examples
- 13. Quiz – How much per year? £10,811 £33,000pa for 25mph wind
- 14. Quiz – How much £21,500 £73,000pa for 25mph wind
- 15. Thank you for Listening Any Questions?