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NORA Advanced Hydronics

National Oilheat Research Alliance 13 Flat Panel Radiators Flat panel radiators are a cross between finned-tube baseboard and radiators. There is not as much mass as a radiator and also fewer fins on the back side. These are typically steel and manufactured to a variety of lengths and heights. The steel mass adds to the radiant energy into the room and the fins help create convective currents. Fan Coils Fan coils are small convectors with fins installed in ductwork. The hot water enters the fan coils and air is circulated in the home by the unit’s own fan blowing across the fins. Radiant Panel Heating Radiant heating systems deliver warmth by radiant heat transfer. A typical radiant floor system heats the terminal unit (floor) anywhere from 75° to a maximum of 85°F. (Figure 14). Supply system temperature can be significantly lower than required in a system relying on convection. Depending upon the radiant installation method, the water temperature needed for heating can be as low as 100°F and up to 180°F. This difference in temperatures can create some challenges when working on a hybrid system, as when, for example, the home has a radiant zone, a baseboard zone and an indirect water heater. In a radiant system, the boiler is typically at a high temperature (around 180ºF) while the radiant system operates at a lower temperature, creating the need for a mixing device. Mixing devices (mixing valve, injection mixing) will send out a lower temperature to the floor panel system by blending the return water from the radiant panel with the boiler water. When a mixing device is used, there must be a circulator after the mixing device to insure flow through the radiant panel. Figure 14


NORA Advanced Hydronics
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