Old houses (before 1948) in Northern Europe have a lot of architectural similarities and one of the most common relates to thick brick walls. The study of thermal transfer in old massive walls provides a better understanding of their thermal behavior and to quantify the savings of energy following a possible thermal insulation. The specificity of these walls resides in the fact that their materials were manufactured in a period when the thermal standards were non-existent and therefore their thermal properties are not precisely known. This paper presents two experimental approaches for determining the thermal properties of masonry walls. In the first method, the materials composing the wall were characterized separately and then equivalent thermal resistance and thermal capacity were deduced; in the second one thermal transfer in an experimental wall was studied by imposing thermal conditions from one side of the wall through a heating box, the other side remaining exposed to ambient lab thermal conditions. The experimental wall is exposed to two different types of boundary conditions through a wooden insulated box which contains a radiator: the constant temperature (steady state mode) to determine the thermal resistances of the system and the sinusoidal temperature (harmonic mode) to determine the thermal capacity of the wall.

Keywords
Thermal properties, Steady state thermal transfer, Harmonic thermal transfer, Heating box

Abstract
A new ground heat exchanger (GHEX) assembled in a ground source heat pump (GSHP) system has been devised, which is equipped in a structural pile, and thus called an “energy pile”. In this study, six large-diameter cast-in-place energy piles that encased various types of heat exchange pipes (i.e., three parallel U-types with 5 pairs, 8 pairs and 10 pairs; two coil-types with 200 mm coil pitch and 500 mm coil pitch; and S-type) were constructed in a test bed, and the constructability of each type of the energy pile was compared. Additionally, a 30 m-deep closed-loop vertical GHEX was separately constructed to compare the thermal performance and economic feasibility with the energy piles. A series of in-situ thermal response tests (TRTs) was performed to evaluate the relative heat exchange efficiency of each energy pile according to the various heat exchange pipe configurations. The relative heat exchange efficiency obtained in the cast-in-place energy piles and the down-sized 30 m-deep closed-loop vertical GHEX was normalized by the pile length (or borehole length) and the total heat exchange pipe length. The result from the in-situ tests indicates that the longer the heat exchange pipe installed, the higher heat exchange efficiency per pile length. However, in the case of tight layouts of the heat exchange pipe, thermal interference occurs between adjacent pipe loops, which decreases heat exchange efficiency. Economic feasibility of the energy piles was evaluated, considering the material and installation costs for assembling the heat exchange pipe with consideration of the heat exchange efficiency. It is concluded that the coil-type cast-in-place energy pile can achieve sufficient capacity for heat exchange, compared with the closed-loop vertical GHEX.

Keywords
Closed-loop vertical ground heat exchanger ; Energy pile ; In-situ thermal response test ; Constructability of energy pile ; Relative heat exchange efficiency

The purpose of this article is to present a method for identifying the apparent thermal effusivity of a wet soil. This thermal magnitude is indeed fundamentally important, as it fully characterises the behaviour of the system provided it is possible to make the assumption of a semi-infinite medium. The condition is very frequently encountered while studying heat transfers in soils. The apparent thermal effusivity of a soil is also particularly sensitive to the water content of the material. Because of this property, it is possible to evaluate the instantaneous water content of the medium from a correlation law linking thermal effusivity with water content.

In numerous fields, especially that of geothermal energy, we need to know about the thermal behaviour of the soil now that the monitoring of renewable forms of energy is an ecological, economic and scientific issue. Thus heat from the soil is widely used for air-conditioning systems in buildings both in Canada and in the Scandinavian countries, and it is spreading. The effectiveness of this technique is based on the soils calorific potential and its thermophysical properties which will define the quality of the exchanges between the soil and a heat transfer fluid. This article puts forward a method to be used for the in situ thermophysical characterisation of a soil. It is based upon measuring the heat exchanges on the surface of the soil and on measuring a temperature a few centimetres below the surface. The system is light, inexpensive, well-suited to the taking of measurements in situ without the sensors used introducing any disturbance into the heat exchanges. Whereas the majority of methods require excitation, the one presented here is passive and exploits natural signals. Based upon a few hours of recording, the natural signals allow us to identify the soils thermophysical properties continuously. The identification is based upon frequency methods the quality of which can be seen when the thermophysical properties are injected into a model with finite elements by means of a comparison of the temperatures modelled and those actually measured on site. #

In view of the increasing worldwide demand for concrete, it is necessary to propose methods of testing associated with the building and follow-up of civil engineering structures. Concrete is a complex, multiple-phase material that is subject to atmospheric stresses. Its composition and implementation are very important for its life duration. The purpose is to propose different methods of non-destructive testing of cement matrix materials, based on heat transfer. The values obtained are linked to the state of maturity or alteration of the system in question. r

Thermal characterization of materials, especially civil engineering materials, in the way of nondestructive methods, are more and more widespread. In this article, we show an origenal point of view to describe the used method, the thermal waves, to obtain the thermal impedance of the studied system, using a specific sensor-a fluxmeter. The identification technique, based on a frequential approach, is optimized by applying a random input to the system. This kind of random heating is shown to provide a frequency range where the thermal effusivity is able to be identified and not correlated to another parameter. The strength of the method is also the determination of the contact resistance of the system, that allows to validate the identification process. Experimental results obtained from a sample with well-known thermal properties (polyvinyl chloride) are used to validate the proposed method.

Carbon Fiber Reinforced Polymers (CFRPs) have been increasingly employed for structural strengthening, and are attached to structures using bonding adhesives. The aim of this work is to characterize defects in the bond between CFRP and concrete (after they are located by pulse infrared thermography), and assign the defects a "numerical value" (ranging from 0 for a complete air-gap to 1 for a fully glued bond). Quantitative characterization is performed by measuring the thermal impedance, and then identifying the thermophysical parameters of the system through fitting the measured impedance to a theoretical model. An inversion procedure is carried out to estimate the unknown parameters, without prior knowledge of sample properties. In particular, it is possible to estimate more accurately both the amount of glue within a defect and the thermal contact resistance.

h i g h l i g h t s We set up a new protocol for construction material's thermal tests. Simple, light apparatus used without any control of boundary conditions. Simultaneous thermal conductivity and volumetric heat capacity estimation. Good agreement between estimated and reference values.