Closed Loop Hydronic Heating System Design

Hydronic system design with the bell gossett.

Closed loop hydronic heating system design.

Nearly all closed loop hydronic heating and cooling systems are supposed to be filled with water or a mixture of water and antifreeze. The system works via pex pipe a small pump a water heater and a thermostat. The circulator acts more like the motor on a ferris wheel. Typically 10 of design flow rate yields about 50 of design heat output.

Since most conventional boilers are designed to produce super hot water 185 degrees radiant floor company builds what we call split manifolds for multiple zone closed systems that use radiant floor heat in combination with standard baseboard radiators fan coils cast iron radiators or any other hydronic heating device that requires super hot temperatures. The only intentional air in the system is contained in the expansion tank. This is about installing hydronic radiant floor heating in a slab floor system. Closed loop system and the weight of the water coming back down the return side acts as a counterbalance.

Heat loss example 10 x 15 room 9 ceilings indoor design temp. 70 outdoor design temp. 2 shows this effect for a heat emitter having a design gt of 20 f. While it was done as a new house was being built in my last house i poured a concrete floor on top of a wood framed floor system and could have put radiant heat in that as well.

The heat output from most hydronic emitters be they baseboard radiant floor circuits or air handlers doesn t vary in proportion to the flow rate passing through them.