Indoor thermal behaviour of an office equipped with a ventilated slab: a numerical study

Abstract

Ventilated slabs are used to provide indoor comfort by taking advantage of thermal inertia. The underlying difficulty is that the computational cost is high, which is hardly compatible with an exhaustive study of dynamic behavior at room scale. This paper presents a methodology for obtaining a lumped model based on the identification of the transfer functions for constant airflow rate systems.The transfer functions were combined into a state space model, which is able to obtain the main heat fluxes with good accuracy at a much lower computational cost. The study moved to room scale in order to further understand how a ventilated slab influences the heat balance. Increasing the number of ducts promoted better indoor temperature stability but the impact was slight. The mass flow rate, on the other hand, appeared to be crucial. This result underlines the need to tailor a control law specifically to the ventilated slab.

Generalizable Thermal Performance of Ventilated Block Walls and Energy Implication of Substitution for Wood-Frame Walls in Cold-Climate Buildings

“…where d is the perpendicular distance between two facing surfaces of the air channel either in the length (∆x) or width (∆z) direction, and W s denotes the width of each surface. The view factor for the adjacent surfaces (perpendicular to each other) can be determined using Equation (14).…”

“…In this system, air circulation can significantly enhance the heat exchange rate (i.e., thermal coupling) between the wall and its surrounding zone, compared to walls without air circulation [8,10]. The majority of research on using active TES in buildings' mass has focused on ventilated concrete flooring and ceiling slabs [13][14][15][16][17][18]. A few studies were conducted to assess the thermal performance of VBWs without outlet air to their associated zones.…”