Transferring the south solar energy to the north facade through embedded water pipes

In the cold sunny winter days, when the south wall is well insulated, a significant amount of solar energy falling on this facade is not transferred to the inside. In this study, a novel closed wall-loop system is proposed to capture this wasted energy available during non-cloudy winter days and transfer it to the cooler north facade through water pipes embedded in an exterior aerogel-based insulating coating. The coating's projection technique through spraying or plastering allows the easy implementation of this system. We present the proposed system with all the mathematical equations and numerical model. This model is then validated against experimental data found in the literature. To test its performance on a full-scale house, this MATLAB numerical model is coupled to the whole building energy simulation program EnergyPlus through co-simulation. Results show that the reductions in the annual heating load for the house adopting this system relative to the one without it are between 28 and 43% for new houses and 15–20% for old houses for Mediterranean climate. For other climates, the reductions vary between 6% and 26%. The heat losses through the north facade are reduced by about 60–88% in the Mediterranean climate and about 20–50% in the other climates.