Simulations and quantitative data analytic interpretations of indoor-outdoor temperatures in a high thermal mass structure

Abstract

The present paper investigates the impact of thermal mass on indoor temperature and reduction of cooling loads in summer. The major contribution of this paper is providing an objective assessment and a quantitative data analytic interpretation from the pattern recognition literature for the reported findings. The experimental study adopted one of the traditional stone structures of medieval Cairo. The house was monitored during summer days for Indoor and outdoor temperatures. Further data for local climate were obtained and given to TRNSYS 17 in which simulations were generated and validated against measured data. The absolute deviance error between simulated and measured indoor temperatures was 0.3°C for a couple of monitored spaces. Data visualization and regression analysis of indoor temperature on two values of outdoor temperature show a relative stability of the indoor temperature, a direct result of the heat storage capacity of the stone walls. A quantitative interpretation of the regression equation tells that the indoor temperature increases by merely 1°C if the outdoor temperature increased by 11.5°C. Upon ambient-temperature-responsive natural ventilation, the maximum indoor temperatures were reduced, in average of 5.5°C and 4.2°C below ambient for two different spaces. A comparative analysis took place then between the base case and a modified model were the walls’ material was substituted with hollow red bricks. For the two rooms, the energy demand for cooling was found to be as less as 72% and 56% in the base case than the brick-walls model.