Effect of integrating high flow naturally driven dual solar air heaters with Trombe wall

Abstract Trombe wall is one of the sustainable architectural designs in the building that offers significant opportunities for energy saving and contribute to the low green-house emissions. Naturally or buoyancy driven dual solar air heaters (SAH) are barely used in building sector with Trombe wall due to its low mass flow rates and low efficiency. In this paper, a new concept of integrating high flow naturally driven dual heating system of Trombe wall integrated with SAH has been numerically investigated, optimized and an efficient design configuration is proposed. Total seven independent configurations namely type-1 to 7 have been investigated wherein type-1 and 2 is SAH coupled with a vertical chimney, type-3 has SAH coupled with Trombe wall, and type-4 to 7 are SAH coupled with Trombe wall having bell-mouth inlet opening for improved hydraulic performance for rapid space heating. It is observed that if Trombe wall is integrated suitably with bell-mouth inlet, SAH along with chimney, it can significantly increase the mass flow rates of heated air by about 2.5 times the convectional design. It is also observed that with increase in mass flow rates, system shows significant exergy gain of 142% when compared to conventional design. Time needed to heat a given space from a specific initial temperature are also calculated using first law of thermodynamics with mass flow values taken from the model and compared with conventional design. It was noted that to heat a given space to a desired temperature, new system of dual SAH takes about 70% less time. The proposed coupled Trombe wall-SAH device has shorter payback period and could save tons of greenhouse gas emissions annually compared to the conventional fossil fuel-based heating systems. Thermal comfort of the occupant can be enhanced with dual SAH-Trombe wall system resulting in significant energy saving.