1. Dans le premier cas, les ailettes en aluminium font un bon travail pour transférer une plus grande partie de l'énergie disponible de l'eau chaude hors du tuyau. En particulier, les ailettes en aluminium placent l'énergie thermique directement sur la face inférieure du sol à chauffer, tandis que les conduits sans ailettes en aluminium chauffent principalement l'air dans la cavité, puis transfèrent l'air au sous-plancher par des mécanismes inefficaces de convection et de conduction d'air chaud . Dans le cas de 5/8″ tubes, une puissance calorifique de 15,124 btu/HR a été observé à température élevée, tandis que la production de chaleur pour 1/2″ le tube était seulement 10,955, ou un 38% augmenter. pourtant, à des températures plus basses (118F contre. 145F), l'amélioration a été moins prononcée, et l'amélioration est tombée à environ 11 pour cent. It’s important to note that the comparisons aren’t quite the same because the 5/8″ tubing is slightly larger than the 1/2″ tubes, but other studies comparing tubing only show that the positive results are mostly attributable to aluminum.
2. Another very important factor in the design of radiant heat is to control the so-called “perte de retour”, ie the heat energy in the wrong direction. Those who would say that heat loss downwards are irrelevant because heat always rises are misguided. The joisted floor application does control heat losses to convection and conduction to near zero in a natural and efficient manner. pourtant, radiant heat can travel in all directions.
Practical experience and these data strongly suggest that if the radiative heat loss in the downward direction is not well controlled, the results will be unsatisfactory. When heat is lost down to another heated space, that heated space may actually be overheated and the intended space is not sufficiently heated. These data strongly suggest that most of the thermal energy provided by the 1/2″ PEX tube without aluminum fins is going in the wrong direction. This situation must be corrected by adding some kind of extra insulation expense. Unfortunately, this This remedy usually does not occur.
An underappreciated advantage of aluminum thermal pads is its low emissivity (nearly zero). This means that when aluminum is heated, it does not emit radiant energy like other materials. In the present case, this characteristic is well used to control the radiation “perte de retour” qui, if left unchecked, can seriously damage the system. The superior effect of the low emissivity is clearly demonstrated by the thermal image, which shows that there is almost no downward radiant heat loss when aluminum is used.
En particulier, the thermograms (below and left) are instructive. Infrared cameras simply “see” the radiative heating spectrum, which is then mathematically corrected to predict molecular temperatures from the measured radiation. This method works for almost all materials except aluminum. It can be seen that the aluminum thermal fins are blue in the temperature record, and the falsely reported temperature is only 67 degrees, when in fact it is 106 degrees. It is worth noting that the actual infrared energy emitted by aluminum is almost zero. The camera is recording reflected radiation from the environment below. These effects reduce the radiation loss of aluminum to near zero.
3. Another useful property of aluminum is that it reflects radiant energy that strikes it from another source. An additional layer of aluminium foil placed under the radiant floor will reflect any misdirected radiant energy. Fortunately, this property can be achieved with extremely thin aluminum foil, which is often bonded to reinforcing paper for strength. This work demonstrated early on the value of foil-faced reflective barriers. Énergie rayonnante qui serait autrement induite en erreur car la perte de retour est réfléchie vers le sous-plancher, où il est utile aux occupants. L'image thermique infrarouge montre clairement l'amélioration du matériau à dos d'aluminium par rapport au papier ordinaire.
