-
-
'15 • HM-T-246
1.5.2 Example of calculation for recirculation load
●
Heat loss from piping (W)
=
Heat loss per unit length of recirculation feed pipe diameter (see table below)
×
recirculation feed pipe length
×
(Recircu-
lation feed hot water temperature
−
Temperature around pipe)
＋
Heat loss per unit length of recirculation return pipe
diameter (see table below)
×
recirculation feed pipe length
×
(recirculation return hot water temperature
−
Temperature
around piping)
=
Heat loss from pipe (W)/(.
×
(Temperature difference between feed hot water
and return hot water on recirculation circuit)
×
,000)
×
0
Table of heat loss from hot water supply piping [W/(m•
℃
)]
•
℃
•
℃
of thermal conductivity for copper pipe is W (m•
℃
), coefficient of thermal conductivity for stainless steel pipe is W (m•
℃
),
•
℃
) and pipe heat insulator thickness ( A ~ 0 A) is
0 mm.
Heat loss from hot water pipe
[W/(m
•
℃
)]
0
0
0
0
Inch
/
/
/
/
/
Heat insulated steel pipe
0.
0.
0.
−
0.
0.
0.
Heat insulated copper pipe
0.
0.
0.
0.0
−
0.
0.
Recirculation feed pipe A
×
0 m, recirculation return pipe 0 A
×
0 m
Feed hot water temperature 0
℃
, return hot water temperature
℃
, ambient temperature 0
℃
Heat loss amount
=
0.
×
0
×
(0 – 0)
＋
0.
×
0
×
( – 0)
=
, (W)
=
,/(.
×
(0 – )
×
,000)
×
0
=
. (L/min)
Heat required for recirculation when the recirculation pump is operated for hours continuously is:
Heat required for recirculation
=
, W
×
H
×
,00
=
.
×
0
J
When the hot water temperature is set at 0
℃
and the return hot water temperature is made at
℃
required for recirculation is:
Hot water volume for recirculation
=
.
×
0
/(.
×
(0 – )
×
,000)
=
, kg
≒
, L
This is nearly equal to ,000 L. Therefore, two 00 L cylinders are required for the recirculation load.
As it is learned from the formula, the recirculation load varies largely depending on the setting of hot water temperature and the
operation time of recirculation pump.
From the viewpoint of energy saving, it is recommended to use lower hot water temperatures and to stop the recirculation
pump in time zones or seasons that do not require recirculation, by a timer, or the like.
AMP Air Conditioning
www.ampair.co.uk | [email protected]
Summary of Contents for ESA30E-25
Page 69: ... 15 HM T 246 AMP Air Conditioning www ampair co uk sales ampair co uk ...
Page 71: ... 15 HM T 246 0 WARNING CAUTION AMP Air Conditioning www ampair co uk sales ampair co uk ...
Page 85: ... 15 HM T 246 4 3 System diagram 㪄㪈㪌㪄 AMP Air Conditioning www ampair co uk sales ampair co uk ...
Page 91: ... 15 HM T 246 0 CAUTION AMP Air Conditioning www ampair co uk sales ampair co uk ...
