Air-to-water Heat Pump Split Versati
19
SPLIT TYPE
Empirical values are worked out under conditions of 80L consumption (per day per person), 8L/min flow rate of
the shower head, and 10 minutes use duration per person.
7 Examples for Model Selection
7.1 General Introduction to the Example Project
For a three-floor apartment, there is a master room and a bath room for each floor and both of them require floor
heating. Other rooms use the heat pump for heating in winter. The master room covers 28m
2
and the bath room
covers 12m
2
.
7.2 Heat Load Calculation
7.2.1 Load Calculation of a Single Floor
Room
Area
Heat Index (W/m
2
)
Heat Load (W)
Master Room
28
82
2296
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:
G=
1.2048kJ/1/3600
h
Q
=0.104m
3
/h
=
If the outer diameter of the heating pipe is 20mm and thickness is 2mm, then the minimum flow for the heating
pipe is:
G=
=3.14/4*
(
20-2*2
)
2
*10
-6
*0.25*3600 =(0.18m
3
)/h
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
G=
4.212kJ/(1/3600h)
Q
=0.3622m
3
/
＞
0.18m
3
/h
=
4.186kJ/(kg
·
℃
)*1000kg/
m
3
*(45-35)
℃
Loop quantity is 0.3622/0.18=2.012 and the round-off number is 2.
