Trombe walls provide a passive source of heating and ventilation for buildings. However, Trombe walls can also cause overheating during hot and sunny weather conditions. In this work, we investigate the potential of a multifunctional Trombe wall design, comprising a tinted acrylic sheet submerged in a water wall that functions as a thermal storage medium. The tinted acrylic sheet absorbs incident light, which is then converted to heat and absorbed by the water. The proposed Trombe wall can function as a tinted semi-transparent window to add aesthetic value. Furthermore, heated water rises to the top of the Trombe wall where it can be removed, which provides the dual benefit of preventing overheating and providing a source of preheated water for applications within the building. Experimental results performed on a laboratory-scale Trombe wall prototype showed that the percentage of solar-simulated light energy incident onto the Trombe wall prototype, over a period of five hours, that was stored as thermal energy in the water increased from 60.3% to 83.2% when tinted glass was inserted in the water storage wall. Furthermore, the temperature of the water at the top of the Trombe wall reached ~56 °C, which is suitable to be used as pre-heated water in building applications.

Trombe walls are a passive solar technology that can contribute to the reduction of building heating loads. However, during warmer weather conditions, Trombe walls may cause overheating. In this work, we investigate the feasibility of using Trombe walls to perform multiple functions during warm weather conditions including (1) heating and storing water for building applications, (2) providing occupants with visibility to the outdoors, and (3) generating electric power. Experiments are performed on a small-scale prototype comprising a clear water storage container with a transparent window and a tinted acrylic sheet that is immersed in the water. Photovoltaic cells are placed on the bottom half of the front face of the water storage container. Results show that water at the top of the clear container can be heated to temperatures as high as 45 °C when subjected to solar-simulated radiation for five hours. Numerical simulations predict that similar temperatures can be reached if the Trombe wall is scaled to full size. Furthermore, the cooler water at the bottom of the water storage container acts as a heatsink that reduces the extent to which the temperature of the PV cells is elevated. Results show the temperature and open circuit voltage of the PV cells are about 50 °C and 0.66 V, respectively, when water is present. However, when the water is absent from the container, the temperature of the PV cells increases up to 90 °C and their open circuit voltage drops to 0.60 V. The results show that water-based, semitransparent photovoltaic thermal Trombe walls have the potential to operate as multifunctional building envelopes that simultaneously provide for daylighting, heated water and electric power, and further research in this area is warranted.

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Thermal energy storage (TES) mediums can be integrated into Trombe walls to improve the utilization of solar energy to offset building energy loads. The vents at the top and bottom of a Trombe wall can be used to manage the flow of heated air through a Trombe wall to store and deliver thermal energy to match the demand profile in buildings. Herein we investigate the thermal energy stored in fire-clay bricks as a sensible storage medium integrated into a scaled Trombe wall prototype. After 3.8 hours under a solarsimulated light source at an intensity of ~325 W/m 2 , ~33 MJ/kg is stored in the fireclay bricks when the vents are open. In comparison, ~37 MJ/kg is stored in the fireclay bricks under similar experimental conditions when the vents are closed. During the discharging phase, which begins when the light source is turned off, it takes ~3.5 hours for the amount of thermal energy stored in the fireclay bricks to decrease by 50% when the vents in the Trombe wall prototype are open. On the other hand, it takes ~4.4 hours for the amount of thermal energy stored in the fireclay bricks to decrease by 50% when the vents are closed. Improved management of solar thermal energy in Trombe walls can reduce the carbon footprint of residential and commercial buildings.