Environmental Engineering Reference
In-Depth Information
SFH-II) are located in the basement of the buildings. Apart from the solar-
supported domestic hot water system of reference system SFH-III, the storages are
charged by an external heat exchanger. The steel buffer storage for the central
heating in the multi-family house with the two-pipe system (variation MFH) is
located in the heating centre. The domestic hot water storages and the heat trans-
fer stations are decentralised and kept in the flats. They are seen as part of the
heating system. For the solar-supported district heating network with short-term
storage (DH-I), the storage is kept in the heating station and the collector area is
installed on the roof or in the neighbourhood to the heating centre.
Table 4.6
Technical data of the analysed solar thermal systems
System
a
SFH-I
SFH-II
SFH-III
MFH
DH-I
Demand for space heating
in GJ/a
22
45
108
432
8,000 (+1,900
network losses)
Demand for domestic hot water
in GJ/a
10.7
10.7
10.7
64.1
Solar system
type of collector
Flat-plate
collector inside
roof, selective
Collector
on roof,
selective
Flat-plate collector inside
roof,
selective
inst. net collector area in m
2
collector loop length in m
technical life time in a
collector efficiency in %
b
spec.
collector yield in kWh/(m
2
a)
c
in MJ/(m
2
a)
c
useful solar heat in kWh/(m
2
a)
d
in MJ/(m
2
a)
d
solar fractional saving in %
e
system efficiency
25
30
20
18.6
219
787
161
578
44
14
25
25
20
21.0
248
893
193
696
31
16
7.4
20
20
28.1
331
1,191
252
906
63 (5.6)
h
21
60
120
20
38.4
453
1,632
327
1,178
10.4
28
620
300
20
26.0
312
1,124
274/221
g
985/795
g
6.2
23/19
g
in %
f
Storage
type of storage
storage volume
tank
2,000
extern
tank
2,000
extern
tank
500
intern
tank
2,000
extern
tank
55,000
extern
in l
heat exchanger
2 x 400
1,364
a
systems SFH-I, SFH-II, MFH and DH-I serve for the solar-supported production of space heating and domestic hot
water; the SFH-III system is solely used for solar-supported domestic hot water heating;
b
useful share of solar radiation
energy at the storage inlet at a mean annual solar radiation of 1,180 kWh/m
2
on the collector area (test reference year
Würzburg, Germany, pointing South, 45° inclination);
c
heat input into the storage (without storage losses);
d
effective
useful solar heat ex storage outlet;
e
for systems SFH-I and -II plus MFH and DH-I related to the demand for space
heating and domestic hot water supply, for system SFH-III related to the demand for domestic hot water;
f
share of the
useful solar heat at the storage outlet of the solar radiation on the collector area; all storage losses are allocated to the
solar system;
g
without/with network losses (15 %) and losses of the house transfer station (5 %);
h
related to the demand
for domestic hot water or the entire demand for space heating and domestic hot water.
Collector pump
connection capacity
2 x 50
1,050
2 x 50
1,173
30
1,435
2 x 75
2,200
in W
annual running time
in h/a
The collector loop of solar thermal domestic water heating (SFH-III) and the
solar combined systems (SFH-I and SFH-II) consist of heat-insulated copper pipes
with a total length of 30 m. For a multi-family house (MFH) a connecting tube
length of 120 m and for a solar district heating system with short-term storage
(DH-I) a pipe length of 300 m is assumed. The hydraulic layout for the solar com-
Search WWH ::
Custom Search