*2.3. Description of the WFG Unitized Module*

All the test cases were triple glazing with a 16 mm argon cavity and a 24 mm water cavity. The water cavity spacer was designed to lead the design flow rate. The circulating device was made of

a plate heat exchanger and a solar water pump. The WFG units were manufactured and assembled in the glass factory and prepared for deployment on-site with an aluminum frame that enclosed the circulating device. The maximum dimension of the panel was 3000 mm high by 1300 mm width. The circulating device main components were a plate heat exchanger and a solar water pump. Its design allowed hydraulic and electrical independence of the modules with a reduced size. The operating flow rate was set to 8 l/min for a 4 m2 module. The circulating device was made of a water pump, selected according to the desired flow rate, and a plate heat exchanger based on the glazing heat capacity. Figure 3 shows a drawing of the circulator with its materials and primary components. Inlet and outlet temperatures were measured using one-wire temperature probes, and a flow meter was placed just before the glazing inlet.

**Figure 3.** Description and general dimensions of the circulating device.

The modular unit hid the complexity of the hydraulic installation, so it became a plug and play product with essential advantages from the product marketing point of view. Depending on the glass selection, the WFG modules offered a broad spectrum of capabilities depending on the location, facade orientation, and use of the building.
