Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 2011

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: heat flux meter

Sortuj według:

Ogranicz wyniki do:

Termografia ilościowa w budownictwie

Wróbel A.

Pomiary Automatyka Kontrola

2011

R. 57, nr 10

1191-1194

Praca dotyczy możliwości wyznaczenia wartości współczynnika przenikania ciepła przez przegrody budowlane na podstawie pomiarów termograficznych. Przeprowadzone długookresowe pomiary laboratoryjne oraz w rzeczywistych budynkach wykazały zgodność gęstości strumienia ciepła z pomiarów ciepłomierzami i termograficznie. Wartość współczynnika przenikanie ciepła nie zależy od techniki pomiarowej ale od warunków wymiany ciepła , czasu pomiaru i sposobu obliczeń.

The aim of this paper is to present possibility of determining thermal transmittance of a wall on the basis of a thermographic survey. Calculation of thermal transmittance is based on formula (1) that determines a relationship between the thermal transmittance, the density of the heat flux through the wall and the air temperature at both its sides in a steady state of the heat transfer. Long-term measurements were taken on different walls in a laboratory as well as in residential houses. The following variables were measured: the heat flux density - using a heat flux meter, the temperatures of air and wall surface - using thermocouples, the difference between the temperatures of air and wall surface at the interior side - from thermograms and air speed at the interior wall surface. The heat flux density was calculated using formula (4) and compared to heat flux meter measurements. The heat flux density measured with a heat flux meter and that determined from thermograms were highly consistent under every heat transfer condi-tions. Therefore, the thermal transmittance (calculated using formula 1) does not depend on whether measurements are taken using a heat flux meter or thermography, but depends on the heat transfer condi-tions. The correct results can be obtained: under steady state heat transfer conditions - by a single measurement, when the boundary conditions change periodically - by averaging measurements in the entire periods, or, otherwise, by averaging measurements over a long time.

Measurements of absorbed heat flux and water-side heat transfer coefficient in water wall tubes

Taler D., Taler J., Kowal A.

Archives of Thermodynamics

2011

Vol. 32, no. 1

77-88

The tubular type instrument (flux tube) was developed to identify boundary conditions in water wall tubes of steam boilers. The meter is constructed from a short length of eccentric tube containing four thermocouples on the fire side below the inner and outer surface of the tube. The fifth thermocouple is located at the rear of the tube on the casing side of the water-wall tube. The boundary conditions on the outer and inner surfaces of the water flux-tube are determined based on temperature measurements at the interior locations. Four K-type sheathed thermocouples of 1 mm in diameter, are inserted into holes, which are parallel to the tube axis. The non-linear least squares problem is solved numerically using the Levenberg-Marquardt method. The heat transfer conditions in adjacent boiler tubes have no impact on the temperature distribution in the flux tubes.