Energy and Power Engineering, 2013, 5, 151-156
doi:10.4236/epe.2013.54B029 Published Online July 2013 (http://www.scirp.org/journal/epe)
Experimental Study of Solar-Assisted Heating System
Jieting Wei1, Yu Gu2, Yang Liu2
1Changchun Institute of Technology,Changchun,China
2Northeast Dianli University,Jilin,China
Received May, 2013
ABSTRACT
Solar heating is a new energy saving technology. This paper studies the operating characteristics of solar-assisted heat-
ing system in Changchun area, the ch anges of the indoor temperature with the conditions of solar-assisted heating sys-
tem .By analyzing these operating data we can see solar-assisted heating to meet the requirements of the indoor tem-
perature and save energy.
Keywords: Solar; Assisted Heating; Energy Saving
1. Introduction
Solar heating is the most potential solar thermal utiliza-
tion technology af ter solar heating the water, it should be
popularized in the future. With the state has increased the
use of renewable energy, and unveiled preferential poli-
cies, solar heating technology has an extensive applica-
tion prospect [1]. As regards the present situation, there
is a wide range of markets for solar energy in our country,
but correlation study is still lacking, the lack of relevant
data, so the experimental build a solar-assisted heating
bench, finishing the test data, provided the basis for data
for the practical application of solar-assisted heating en-
gineering.
At present, the terminal device for most of the solar
heating system are used radiant floor heating, however,
terminal devices of most of the existing residential
buildings are radiators, so this paper studies solar as-
sisted radiator heating system.
2. The Experiment of Solar-assisted Heating
System
In an energy-efficient building, selected a 58m2 room as
an experimental room, and selected another room as the
comparison room that the size, towards and maintenance
structure are the same with the experimental room. Ac-
cording to calculation th e heating load of the experimen-
tal room is 3480W .The experimental system uses the
Huayang vacuum tube solar water heater, collector area
is 3.83, the tank capacity is 250 L. The system is lack of
elevated water tank, not able to meet the conditions of
the natural cycle (solar energy can be used as an elevated
water tanks, the reason for it can not natural cycle is that
the heat source and the heat dissipation center can not
formed the height difference). Therefore, there is a 290w
miniature pump in the system as a cycle power, the suc-
tion inlet of the pump is connected heat source, the direc-
tion of flow: heat source→ pump → radiator.
The experimental procedure is as follows: solar col-
lector absorbs solar radiation, transforms it into heat en-
ergy stored in the storage tank for room heating, and
composes of a set of sola- assisted heating system with
the end of the heat dissipation device.
There are four long airfoil radiators, two intelligent
temperature control strong convection radiators, two ra-
diators through the valve can series parallel used, and can
run separately, so that can satisfy the requirements of
different indoor temperature. In summer, when the in-
door temperature is too high, to pass the tap water into
the intelligent temperature control strong convection ra-
diators, after heat transfer treatment sending cold air to
the room to eliminate waste heat, similar to the role of a
simple split air-conditioning , to maintain the temperature
of the interior cool. In winter, under normal circum-
stances, only use the long airfoil radiator heating to meet
the requirements of indoor temperature, when outdoor
temperature mutation or fluctuations in a very obvious
situation can be appropriate to open the intelligent tem-
perature control strong convection radiators, to ensure
that the interior parameters are maintained within the
desired temperature range. By two radiators combined
operation (forced convection heat transfer and natural
convection heat transfer) is sufficient to meet the heating
requirements of the room.
Data collection included the supply water temperature
of radiator t1, the return water temperature of radiator t2,
indoor temperature of the heating roomt3, indoor tem-
perature of the non-heating room t4, outdoor air tempera-

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152
ture t5, wind speed v, solar radiation intensity.
Heating system as illustrated below.
3. Experimental Data and Analysis
There are two cases of the experiment: one for fine
weather, sunny, without opening the auxiliary heating
device will be able to meet the basic needs of the in terior;
Another situation is the rainy weather, lacking of inten-
sity of solar radiation, the need to open the auxiliary
heating equipment to meet the basic needs of the interior.
Now analysis the test data results of both cases.
Experimental results and analysis are as follows
3.1. Experimental Data and Analysis without
Auxiliary Heating Equipment
Figure 2 shows contrast curves of the indoor temperature
of the heating room, indoor temperature of the non-
heating room and outdoor air temperature. Table 1 lists
the peak point on the curve. From above, it can be seen
that the trend of the indoor and outdoor temperature is
substantially same. The average temperature of the heat-
ing room is 22..23℃, and the average temperature of the
non-heating room is 18.52℃. The average temperature of
the heating room is high er than the non-h eating room 1.1
℃ ~ 5.7℃.
Figure 1. The system diagram of the solar-assisted heating.
Table 1. The equipments name of the solar-assisted heating system.
1 Solar collectors 7 Temperature Sensor Placement
2 Heat Storage Water Ta n k 8 Water Overflow Port
3 Long Airfoil Radiator 9 Connect Tap Water
4 Intelligent Temperature Control Strong Convection Radiator10 Heating supply water
5 Circulating Wat er Pump 11 Heating return water
6 Electric Heater
Figure 2. The comparison chart of indoor and outdoor temperature.
Table 2.
X Axis（Time） Y Axis（Temperature /℃）
1 15:20 24.62
2 14:50 19.34
3 14:50 -1.35

J. T. WEI ET AL. 153
Figure 3 shows contrast curves of the radiator supply
and return water temperature and heating load. Table 2
shows the supply and return water temperature on the
curve, the peak point of heating load. The loading heat Q
is calculated after measured system flow rate.
(1)
According to the formula (1) the loading heat of ra-
diator is calculated. We can educe that the trend of the
radiator supply and return water temperature is broadly
similar. The average temperature difference of the radiator
supply and return water temperature is 7℃ ~10℃.
Figure 4 shows the contrast curves of the radiator
supply and return water temperature and solar radiation
intensity. Table 1 lists the maximum value of solar ra-
diation intensity and radiator supply and return water
temperature. This shows that the trend of the radiator
supply and return water temperature and solar radiation
intensity is broadly consistent. The peak of the radiator
supply and return water temperature delay compared to
the intensity of solar radiation, wh ich is cau sed du e to the
regenerative properties of the water tank.
Figure 5 shows comparison graph of the indoor and
outdoor temperature, loading heat. Table 4 lists the
maximum worth of indoor temperature of the heating
room, indoor temperature of the non-heating room, out-
door air temperature and the loading heat of the heating
room. This shows that when the outdoor temperature is
high, the room temperature and loading heat to obtain the
maximum.
Figure 3. The comparison chart of radiator supply and re-
turn water temperature and heating load.
Table 3.
X Axis（Time） Y Axis（Temperature /℃）
1 14:30 61.679
2 14:30 51.679
3 15:00 1.9087（Heating Lo ad/ KW ）
Figure 4. The comparison chart of radiator supply and re-
turn water temperature and solar radiation intensity.
Table 4.
X Axis（Time） Y Axis（Temperature /℃）
1 12:30 664（solar radiation intensity/W/m2）
2 14:30 61.679
3 14:30 51.679
Figure 5. The comparison chart of indoor and outdoor
temperature and heating load.
Table 5.
X Axis（Time） Y Axis（Temperature /℃）
1 15:30 24.539
2 14:50 19.335
3 15:00 1.9087（Heating Lo ad/ KW ）
4 14:50 -1.75

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154
3.2. Experimental Data and Analysis with
Auxiliary Heating Equipment
Figure 6 shows the contrast curve of the radiator supply
and return water temperature and heating load when
opening the electric heater. Opened the electric heater at
8:00, closed it after one hour. It reached a small peak of
the radiator supply and return water temperature and
heating load at 9:00.After that it operated independently
rely on solar radiation .Opened the electric heater auxil-
iary heating again at 15:00 pm, closed it after one hour. It
reached a small peak again at 16:00, but with the electric
heater was turned off, all the value were gradually re-
duced. The value all showed in Table 5.
Figure 7 shows comparison chart of radiator supply
and return water temperature and solar radiation intensity
when opening the electric heater. Table 6 shows the val-
ue of each point. Opened the electric heater at 8:00,
closed it after one hour. The solar radiation was strongest
and radiator supply and return water temperature reached
the maximum value at 11:20. With the intensity of solar
radiation, the supply and return water temperature gradu-
ally weakened, Turned on the electric heater again for
one hour at 15:00. Thus, the radiator supply and return
water temperature is controlled by the intensity of solar
radiation.
Figure 6. The compar ison chart of radiator supply and return w ater temperatur e and heating load whe n opening the elec tric
heater.
Table 6.
9:00 11:40 16:00
Y Axis (Temperature/)℃ Y Axis (Temperature/℃) Y Axis(Temperature/℃)
1 48.265 4 50.695 7 52.203
2 36.226 5 40.734 8 40.156
3(Heating Load) 2.8164KW 6(Heating Load)2.4694KW 9(Heating Load) 2.8182KW
Figure 7. The compar ison chart of radiator supply and return w ater temperatur e and solar radiation intensity when opening
the electric heater. Table 7.

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8:00 9:00 11:20
Y Axis(Temperature/)℃ Y Axis(Temperature/)℃ Y Axis(Temperature/)℃
1 42.484 4 48.265 7 (radiation intensity) 527 W/m2
2 33.898 5 36.226 8 48.554
3 (radiation inte nsity) 53 W/m2 6 (radiation intensity)311 W/m2 9 40.734
15:00 16:00
Y Axis(Temperature/)℃ Y Axis(Temperature/)℃
10 (radiation int e n sity) 310 W/m2 13 52.203
11 44.725 14 40.156
12 36.585 15 (radiation intensity) 182 W/m2
Figure 8. The comparison chart of indoor and outdoor temperature and heating load when opening the electric heater.
Table 8.
8:00 9:00 11:30
Y Axis(Temperature/)℃
Y Axis(Temperature/)℃Y Axis(Temperature/)℃
1 20.843 5 22.453 9 25.648
2 17.546 6 18.015 10 19.054
3(Heating Load) 1.7687KW 7(Heating Load)2.8164 KW 11(Heating Load) 2.4694 KW
4 -15.6 8 -13.6 12 -10.8
15:00 16:00
Y Axis(Temperature/)℃ Y Axis(Temperature/)℃
13 21.906 17 22.375
14 18.617 18 16.585
15(Heating Load) 1.8474 KW 19（Heating Load） 2.8182 KW
16 -10.4 20 -12.4
Figure 8 shows comparison chart of the indoor and
outdoor temperature and heating load when opening the
electric heater. Table 7 respectively lists the value of
each point. From the graph can be seen, opening the
electric heater can increased significantly the room tem-
perature and the heating load, the temperature can im-
prove an averag e of 1℃ ~ 2℃. This shows, the effect of
the solar- assisted heating system is common decision by
the solar radiation intensity and th e outdoor temperature
4. Energy Saving Quantity of the
Solar-assisted Heating System
Take 40% solar fraction, the number of heating period in
Changchun is 170 days, heating load of The room is
3480 W. Thus the heating load for one day is 3480 ×
24/1000 = 83.52 Kwh = 300.67 MJ. Thus the total en-
ergy saving quantity is Q = 40% × 170 × 300.67 =
20445.56 MJ = 4891 Mcal. The heat of the definition of
standard coal in China is 7000 kcal/kg (7 Mcal/kg).
Therefore a heating season can save standard coal: 698
kg. There will be a huge con tribution to energy con serva-
tion.
5. Conclusions
By the above experiments and the collation of data, we
can see that the use of solar-assisted heating in Chang-
chun is feasible and have a certain effect. The solar col-
lector area of the experimental system is 3.83 m2, the
room area is 58 m2 ,in the case of Changchun region
sunshine, the rise of the room temperature can reach 4℃,
and thus see, in energy-efficient buildings 1 m2 solar
collectors as an auxiliary heating can heat 15 m2 room.
Through the experiment, conclusions are drawn as
follows:
1) Solar-assisted heating can meet the temperature re-
quirements of room, the average temperature of the

J. T. WEI ET AL.
156
heating room reaches 22℃ on average higher than non-
heating room 4℃
2) The operating results of the solar-assisted heating
system by the solar radiation, the outdoor temperature as
so on. The system supply and return temperature differ-
ence maintain in 7℃.
3) In energy-efficient bu ildings, th e proportion of solar
collector area and room area is1:15.
4) Changchun area belongs to the area of solar energy
resources are abundant, solar heating is both environ-
mentally friendly and energy conservation, research
should be fo cused.
REFERENCES
[1] Z. N. He and D. Z. Zhu, “Solar Heating Application
Manual,” Beijing: Chemical Industry Press, 2009.