Glazing that uses water for heating

Dr. Matyas Gutai of Loughborough University has created the «Water-Filled Glass» (WFG) system, which uses water to heat and/or cool buildings.

The basic element of the system is a window panel filled with water. The panels are connected to one another and to the main tank through pipes concealed in the walls.

In hot climates, buildings stay cool because the water absorbs external and internal heat and is pumped into a storage tank, replaced by cold water. The warmed water can then be used for household purposes or diverted back into the walls and windows when outdoor temperatures drop.

Colder climates require a more advanced version of the system. It includes a heat pump that heats the water in the main tank and pumps it through the system to circulate it. The pump uses far less energy than traditional systems such as heating, ventilation, and air conditioning.

For the study, two prototype houses with WFG were built — in Hungary and Taiwan. (The house in Hungary was a finalist for the international World Architecture Festival 2020.) The resulting usage data was used to extend the simulation to all major climate zones — tropical, arid, temperate, continental, and polar.

In his latest study, Dr. Gutai compares the efficiency of the WFG system with a traditional heating system (double- and triple-glazed windows paired with gas heating and air conditioning) and reaches the following conclusions:

• The WFG system reduces heating and cooling loads by minimizing daily and seasonal peaks.
• The WFG system saves energy in all climate regions except the polar zones, with savings of:
• 47%−72% compared with double glass.
• 34%−61% compared with triple glass filled with argon.

The additional benefits include improved acoustics.