Glazing with water as a heater

Dr. Mathias Gutai of Loughborough University created the «WATER-FILLED GLASS» (WFG) system, which uses water to heat and/or cool structures.

The basic element of the system is a window-panel filled with water. They communicate with each other and the main tank through pipes concealed in the walls.

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

For colder climates, a more advanced version of the system is needed. It includes a heat pump that heats the water in the main tank and pumps it in to circulate it. The energy used by the pump is much less than in traditional schemes such as heating, ventilation and air conditioning.

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

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

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

The additional positive features include improved acoustics.