A low cost, accurate instrument to measure the moisture content of building envelopes <i>in situ</i>

Buildings must be designed and built to achieve a healthy environment, low energy consumption and a predictable service life. In order to achieve these goals the effects of combined heat, air and moisture (HAM) transfer must be understood. A suitable moisture measurement technique is thus required. There is a pressing need for a suitable instrument capable of <i>in situ</i> moisture measurements in building envelopes. Techniques do exist for such moisture measurement but all exhibit deficiencies in at least one critical area. A thermal dual-probe is investigated as a candidate for an appropriate instrument as such an approach offers significant potential benefits over existing methods.<br></br><br></br>It is demonstrated, via extensive finite-element (FE) modelling, that the thermal dual-probe technique is indeed applicable to in situ moisture measurements in typical building fabrics. <br></br><br></br>The thesis then moves on to deal with the <i>optimisation</i> of the design of such a probe. The results of relevant simulations using the proven two and three-dimensional FE models are detailed.<br></br><br></br>Finally, the extensive experimental work undertaken to support the modelling work is described. The measured data obtained from the thermal dual-probes is compared with the results of series of gravimetric analyses. Close agreement between the two methods is obtained.<br></br><br></br>The work, has successfully demonstrated that, depending upon the building fabric material,optimal probe lengths and spacing range from approximately 45-60mm and 12-20mm respectively. The experimental work clearly indicates that the thermal dual-probe is capable of accurate, <i>in situ</i> moisture measurements in building envelopes.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

The Open University

Year dc:date.issued

2005

Author dc:creator

• Ye, Zhihui

Language dc:language

en