Review on Energy and Fire Performance of Water Wall Systems as a Green Building Façade

Uthpala Rathnayake,Cheuk Lun Chow,Denvid Lau

doi:10.3390/su12208713

Uthpala Rathnayake, Cheuk Lun Chow + Show 1 more

Open Access

https://doi.org/10.3390/su12208713

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Abstract

Glass façades are widely utilized in green buildings. Ensuring fire safety while reducing the energy need without compromising occupants’ comfort is a challenge in the modern-day green buildings with glass façades. One way of achieving both aspects is to construct a water wall system as a building façade. A water wall system has a water layer between two glass panes and can be considered as a glass façade system. The focus of this review, which builds on the published studies, is how water wall systems can help ensure fire safety and reduce energy demand in green buildings. The water layer within two glass panes of the water wall system store the solar radiation heat throughout the daytime, reducing the amount of heat transferred through the building facade. The reduced heat transfer effects lessen the need for air conditioning to sustain the thermal comfort of the building occupants. The stored energy is released during the nighttime. The transparency of the water wall system also allows daylight to enter the building, thus reducing artificial lighting needs. Furthermore, the water layer acts as a fire safety mechanism in case of a fire. However, the water wall systems are not much utilized in the modern-day green buildings due to their unpopularity and the unavailability of design guidelines. On the basis of the findings of the literature review, stakeholders and the public are encouraged to adopt water wall systems in green building projects as an energy-efficient strategy and a fire safety mechanism.

Highlights

The façade, which is the skin of the building, separates the interior space from the external environment
The results revealed that the combined effect of a Water wall systems (WWS) with Phase Change Materials (PCMs) gave the best thermal performance over all other WWS arrangements considered
Water drums behind glass panes improve the thermal comfort inside the room Solar heat gain in transwall is very close to the solar heat gain of Trombe wall

Summary

Introduction

The façade, which is the skin of the building, separates the interior space from the external environment. Apart from energy efficiency, green building façades have a less negative impact on the environment and provide a better indoor environment that might contribute to wellbeing, productivity, and performance of the occupants For this purpose, a green building façade should satisfy several requirements, such as facilitating outside views, withstanding wind loads, air and water penetrations, sustaining its dead load weight, allowing daylight to the building interior, obstructing undesirable solar heat gain, blocking outside noise and reducing temperature fluctuations, and boosting the overall building performance [5,6,7,8]. If not correctly designed, solar gain through heat transmittance of glass façades can be as high as 85% of the incident radiation [14] This transferred heat raises the air temperature inside the building, creating a high demand for air conditioners to keep up the occupants’ thermal comfort. Careful consideration is needed in designing the glass façades to get the delicate balance of energy over the building envelope together with adequate daylight to reduce the artificial lighting [2,20,21,22]

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