Thermal Transmission through Existing Building Enclosures: Destructive Monitoring in Intermediate Layers versus Non-Destructive Monitoring with Sensors on Surfaces

Abstract

Opaque enclosures of buildings play an essential role in the level of comfort experienced indoors and annual energy demand. The impact of solar radiation and thermal inertia of the materials that make up the multi-layer enclosures substantially modify thermal transmittance behaviour of the enclosures. This dynamic form of heat transfer, additionally affected by indoor HVAC systems, has a substantial effect on the parameters that define comfort. It also has an impact on energy demand within a daily cycle as well as throughout a one-year use cycle. This study describes the destructive monitoring of an existing block of flats located in Alicante. Once the enclosure was opened, sensors of temperature (PT100), air velocity, and relative humidity were located in the different layers of the enclosure, as well as in the interior and exterior surfaces. A pyranometer was also installed to measure solar radiation levels. A temperature data correction algorithm was drawn up to address irregularities produced in the enclosure. The algorithm was applied using a Raspberry Pi processor in the data collection system. The comparative results of temperature gradients versus non-destructive monitoring systems are presented, providing measures of the transmittance value, surface temperatures and indoor and outdoor air temperatures. This remote sensing system can be used in future studies to quantify and compare the energy savings of different enclosure construction solutions.

The Passivhaus Standard in the Spanish Mediterranean: Evaluation of a House’s Thermal Behaviour of Enclosures and Airtightness

“…The two domains of evaluation of the house's energy demand are linked to the materials used as well as the technical characteristics of the enclosures, although they are of a very different nature. Evaluating the actual heat flow through the enclosures throughout the year's entire cycle is a complex matter [36]. This evaluation requires simulation models that take into account construction faults, the impact of thermal inertia, real thermal bridges, as well as the incidence of solar radiation on the exterior surfaces and the air conditioning systems used.…”

“…Evaluating the actual heat flow through the enclosures throughout the year's entire cycle is a complex 264 matter [36]. This evaluation requires simulation models that take into account construction faults, the 265 impact of thermal inertia, real thermal bridges, as well as the incidence of solar radiation on the 266 Figure 5.…”

Energy rehabilitation of buildings through phase change materials and ceramic ventilated façades

“…The system creates a continuous barrier that protects the thermal envelope and prevents thermal bridges that cause energy losses in the building. This type of façade enables reducing energy demands and improving comfort levels [9]. Due to its characteristics, the system has also gained importance in parts of southern Europe such as Alicante.…”

“…Several studies have demonstrated how radiant floor heating and passive cooling by convection using energy storage systems based on PCMs function correctly in the construction field [9]. Results obtained by researchers on PCMs in a Mediterranean environment led us to opt for inorganic hydrated salts as they are inexpensive and offer a large heat storage capacity per volume unit [8].…”

“…According to the statistics of the International Energy Agency (IEA), around 30% of energy supply is lost during its conversion, that is, due to dissipation or thermal costs [9].…”