Gree GRS-CQ8.0Pd/NaEK - Arrangement Design of the Underfloor System for a Single Floor; Arrangement Design of the Underfloor System for the Bath Room; Arrangement Design of the Underfloor System for the Master and Bath Rooms; Check

Design and Selection
36
Bathroom
12
72
900
Total Load
2296+900=3196W
7.2.2 Arrangement Design of the Underfloor System for A Single Floor
Assumed conditions: the floor is cement or ceramics, the normal external diameter of the heating
pipe is 20mm, thickness of the stuffer is 50mm, thickness of PS foam insulation is 20mm, supply water
temperature is 45°C, return water temperature is 35°C, indoor design temperature is 20°C
Average Temperature of the Heating Pipe=(45+35)/2=40°C
7.2.3 Arrangement Design of the Underfloor System for the Bath Room
Heat load of the bath room is 900W, heat dissipation per unit area is 75W/m
2
, tube spacing of the
heat pipe is 30mm, and heat loss is 25.4 W/m
2
, then the total heat loss is:
25.4×12=304.8W
Based on the heat load listed in the table above, the heating load for the bathroom is:
900+304.8=1204.8W
According to the formula Q=CρGΔT, the flow rate of the heating pipe for the bathroom is:
If the outer diameter of the heating pipe is 20mm and thickness is 2mm, then the minimum flow for
the heating pipe is:
It can be see that the arranged piping system for the bathroom does not meet the technical
requirement and must be used in common for the master room.
7.2.4 Arrangement Design of the Underfloor System for the Master and Bath Rooms
According to the calculation results, the total heat load for the master and bath rooms is 3196W,
heat dissipation per unit area is 82W/m
2
, tube spacing of the heating pipe is 300mm, and heat loss is
25.4 W/m
2
, then the total heat loss is:
3196+1016=4212W
According to the formula Q= CρGΔT, the flow rate is
Loop quantity is 0.3622/0.18=2.012 and the round-off number is 2.
7.2.5 Check
A. Check for the flow rate
Floor rate of each loop is within 0.25~0.5m/s and the system can run stably.
B. Check for the tube length
When the average tube spacing is 30mm, the required length of the heating pipe per square meter is
3.5m, length of total coils is 3.5×40=140 and length for each loop is 140/2=70.
It can be seen that the length for each loop is less than 120m and there it meets the design
requirement.
C. Check for the ground average temperature
tp=tn+9.82×(qx/100) 0.969=20+9.82×(82/100) 0.969=28°C
Upper Limits and Average Floor Temperature
Average Floor Temperature
Area
Average Temperature
Maximum Temperature