Труды Всемирного конгресса Международного общества солнечной энергии

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Proceedings of ISES Solar World Congress 2007: Solar Energy and Human Settlement

932

Apparatus No. 1 or No. 2 is a tube wound with two ribbon

electric heaters. The thickness, the width, and the length of

one heater are 1mm, 20mm, and 500mm, respectively. The

rated power consumption of one heater is 250W. The power

of the two heaters is varied by resistors from 0 to 500W.

In order to estimate the temperatures of the water in the

tube, condenser, or reservoir, the temperatures T

, T

and T

are measured at the center of the evaporator, at the

condenser inlet where the water in the two phases flows

through, on the wall of the reservoir, at the condenser outlet

where the condensed liquid flows out, and at the inlet of the

cooler, respectively. T

and T

are measured between the

cooler and condenser and at the inlet of the condenser,

respectively. The temperature of the water in the cooler, T

was also measured. Most of the experiment are carried on

at T

of about 20͠

3. RESULTS AND DISCUSSIONS

Figs. 3 and 4 show the variation of the temperatures with

time when the heat inputs at the evaporator were 200W and

400W, respectively for the Apparatus No. 1. The

temperatures of the water in the water bath, T

, were about

20ºC in the beginning of the experiments. The temperature

of the water in the water bath did not controlled in these

cases so that it increased with time. The temperature at the

evaporator, T

, and the wall of the heat exchanger

(condenser), T

, increased with time until around 70

minutes at the heat input Q

of 200W and 30 minutes at Q

of 400W. The temperatures became about 120ºC. It can be

known from Fig. 3 and 4 that just before these times the

temperatures at the inlet of the cooler, T

, started to

increase just before these times. If there had been a flow in

the loop, then the temperature of the working fluid at the

inlet of the cooler, T

, should have been higher than the

temperature of the water in the cooler, T

. Since T

and T

are about the same, there must be no flow-circulation

before these times. There was no result about the variation

of temperatures with time in Ref. 1, but it was described in

the paper that the water in the loop did not circulate for a

while in the beginning of the experiments and them the

fluid temperature in the evaporator and the heat exchanger

continued to rize slowly. Because the temperature of the

coil of the tube in the condenser would be the same as the

water in the condenser at the beginning of operation, the

vapor would not be condensed on the surface of the coil.

Then, the vapor would increase the temperature of the

water and the coil. Heat would be transferred from the coil

to the inlet of the tube so that the temperature of the tube at

the inlet of the condenser, T

, would increase as shown in

Figs. 3 and 4. Because of the heat conducted through the

coil to the tube at the inlet, the temperature on the surface

of the coil would become lower than the vapor. The

difference of the temperatures between the vapor and the

coil became large with time and the rate of condensation

would increase with time. It is assumed that when the rate

of condensation became large enough, the circulation

started.

100

120

140

0 60 120 180

Time

䋬

min

㧘͠

Fig. 3: Variations of temperatures with time for Apparatus

No. 1, Q

=200W.

100

120

140

060120180

䌔䌩䌭䌥䇭䋬

min

䌔䇭䋬㷄

Q =400W

Fig. 4: Variations of temperatures with time for Apparatus

No. 1, Q

=400W.

On the other hand, the temperature at the inlet of the cooler,

increased from the beginning in case of Apparatus No. 2

as shown in Figs. 5 and 6. When the heat input was 200W (cf:

Fig. 5), the temperature at the inlet of the cooler , T

, went

up and down during the time between 10 and 40 minutes

and between 80 to 90 minutes. It is expected that the fluid

3 SOLAR COLLECTOR TECHNOLOGIES AND SYSTEMS

933

temperature in the tube between the cooler and the

condenser, T

, would be close to the temperature of the

water, T

, when there was a flow circulation. When the

flow stopped the temperature on the tube between the

cooler and the condenser, T

would be influenced by the

temperature of the condenser at the exit of condenser, T

by heat conduction so that T

increased when the flow

stopped. The evaporation temperature was higher when the

flow was unstable than when the flow was stable as seen in

Fig. 5. Fig. 6 shows the experimental results when the heat

input was 400W. The variations of the temperatures with

time were not so large as the case of the heat input of 200W.

Since the difference between the temperature at the inlet of

the condenser, T

, and the temperature at the inlet of the

cooler was about 5ºC, the length of the condenser was

considered to be long enough. If the length of the

condenser had been too short, the temperature at the inlet of

difference would have been much larger.

100

0 306090

Time

䋬

min

䋬㷄

Q =200W

Fig. 5: Variations of temperatures with time for Apparatus

No. 2, Q

=200W.

100

03060

Time , min

䌔䇭䋬㷄

Q =400W

Fig. 6: Variations of temperatures with time for Apparatus

No. 2, Q

=400W.

Fig. 7 shows the experimental results when the temperature

of the water in the bath was kept at about 52ºC and the heat

input was 400W. The condensation temperature which

would not be so different as the evaporation temperature in

the evaporator was about 80ºC at the maximum. Using

solar collectors as the heater, this type of top-heat loop

thermosyphon would be able to use as the solar water

heater without pumping.

100

0306090

䌔䌩䌭䌥䇭䋬

min

䌔䇭䋬㷄

Q =400W

Fig. 7: Variations of temperatures with time for

Apparatus No. 2, Q

=400W, T

=52͠.

4. CONCLUSIONS

A top–heat loop thermosyphon in which the condenser

combined reservoir started transfer of the heat supplied at

the evaporator to the cooler after the temperature of the

water became 120ºC. The modified top-heat loop

thermosyphon in which the condenser and the reservoir

were separated operated successfully from the beginning of

heating. The temperature on the outside wall of the

evaporator was in the range between 60ºC and 90ºC. The

evaporation temperature was lower when the flow was

stable than when it was unstable. It would be possible to

apply this device to solar water heating. Further

investigations will be necessary for the application.

5. ACKNOWLEDGEMENT

The support of “High-Tech Research Center Project for

Private Universities: matching fund subsidy from MEXT,

2007-2011” for this research is appreciated.

Proceedings of ISES Solar World Congress 2007: Solar Energy and Human Settlement

934

6. REFERENCES

(1) S. Ippohshi, “Development of a Top-Heat –Mode Loop

Thermosyphon”, Proceedings of the 6th ASME-JSME

Thermal Engineering Joint Conference, 2003,

TED-AJ03-578

(2) G. L. Morrison, “Solar Water Heating”, Solar Energy

edited by J. Gordon, 2001, International Solar Energy

Society, p.223-289

(3) Yu. Maydanik, “Loop Heat Pipes-Highly Efficient

Heat-Transfer Devices for Systems of Sun Heat

Supply”, Proceedings 1 of EuroSun 2004 Conference,

2004, p.470-476

PERFORMANCE OF SOLAR ASSISTED HEAT PUMP USING PV EVAPORATOR UNDER

DIFFERENT COMPRESSOR FREQUENCY

Gang Pei, Jie Ji, Chongwei Han, Wen Fan

Department of Thermal Science and Energy Engineering, University of Science and

Technology of China, ChinaˈEmail: peigang@ustc.edu.cn

ABSTRACT

A novel photovoltaic solar assisted heat pump (PV-SAHP)

system was constructed with the PV cells laminated onto

the evaporator-collector plate. So a portion of the solar

energy received was converted to electricity and the rest

was converted as heat. The heat energy was then absorbed

by the refrigerant and carried over to the condenser.

Photovoltaic efficiency was increased in this way due to

the lowered PV cell operating temperature as a result of

the refrigerant evaporation process. The COP of the heat

pump was also substantially improved because of the

solar energy absorption. Performance tests under

frequency 40Hz, 60Hz of compressor were conducted on

the experimental rig. The dynamic performance of this

PV-SAHP system was analyzed and the influencing

factors were identified. The results indicate that this

PV-SAHP system has a superior performance than the

conventional heat pump system and at the same time, the

photovoltaic efficiency is also higher.

1. INTRODUCTION

One recent development in the integration of heat pump

and solar technology lies in the use of direct-expansion

solar collectors to replace the standard air source

evaporator in a heat pump system. This heat pump system

using solar radiation as the evaporating heat source is

known as the solar assisted heat pump (SAHP) system. The

advantage of this, from the heat pump technology point of

view, is the higher evaporating temperature of refrigerant at

the evaporator-collector owing to the solar heating effect.

This increases the COP of the heat pump. From the solar

technology point of view, the refrigerant as the working

fluid at the solar collector undergoes phase change at a

relatively low temperature. The energy conversion

efficiency is therefore improved.

The concept of SAHP was first proposed by P.Sporn (1955)

in 1950s[1]. Since then the progress of the technology had

been slow, and took shape not until 30 years later when the

global problems of energy shortage, environmental

pollution and greenhouse effect became known. Recently,

M.Hawlader (2006) and J.G.Cervantes et al. (2002)

conducted their individual experimental projects on SAHP

in different climatic regions[2,5]. Their research works

contributed to the photothermic utility of solar energy and

the thermal performance of heat pump.

In the context of renewable energy, the direct conversion of

solar energy into electricity by means of photovoltaic (PV)

modules has received much attention since the 90s. The

majority of the solar radiation on the PV module is

converted as heat, which results in an increase of the PV

cell operating temperature and a lowered photovoltaic

efficiency. To overcome this limitation, many research

efforts have been switched to the hybrid

photovoltaic/thermal (PV/T) technology. Jr.E.C.Kern (1978)

first outlined this main concept in the 1970s[4]. Among the

alternative system designs relatively known so far, one

design approach deemed to have very good marketing

Proceedings of ISES Solar World Congress 2007: Solar Energy and Human Settlement

936

potential is the simultaneous production of electricity and

hot water.

Although a water-based PV/T system is able to achieve a

higher overall energy output per unit collector area than the

“side-by-side” systems, for daily operation the photovoltaic

efficiency of the hybrid system still will drop considerably

towards the end of the day, when the heat removal fluid

(water) temperature in the storage tank will finally reach

the level that meets the hot-water demand requirements. If

the evaporating refrigerant of a heat pump is used as the

coolant of the PV cells, a lower operating temperature and

accordingly a higher PV efficiency can be achieved.

In the Rankine refrigeration cycle operation, the solar

energy absorbed by the refrigerant at the evaporator will be

released later on at the condenser with a higher working

temperature. S.Ito and N.Miura (1997) constructed a SAHP

system with a PV/T evaporator based on this principle

[7]

The experimental results indicated that the COP of the heat

pump could be as high as 6.0, when 40 ć water was

supplying to the condenser. It was also concluded that the

PV modules attached on the solar collectors did not affect

much the performance of the heat pump. However, the PV

or the overall PV/T performance in the system was not

covered in their publications.

In this study, a novel PV-SAHP system was constructed

with the PV cells laminated onto the evaporator-collector

plate. So a small portion of the solar energy received was

converted to electricity and the rest was converted as heat.

The heat energy was then absorbed by the refrigerant and

carried over to the condenser. Photovoltaic efficiency was

increased in this way due to the lowered PV cell operating

temperature as a result of the refrigerant evaporation

process. The COP of the heat pump was also substantially

improved because of the solar energy absorption. Presented

below are the working principle, the testing method and the

dynamic photovoltaic/thermal performance of our

experimental PV-SAHP unit.

2. EXPERIMENTAL SET-UP

The basic components of PV-SAHP system include: PV

evaporator, air evaporator, variable-frequency compressor,

air-cooled condenser, water-cooled condenser, electricity-

operated expansion valve. There were other accessories

such as refrigerant filter, liquid trap, four-way valve,

anti-vibration mounting and auxiliary capillary tubing. R22

was used as the refrigerant in this heat pump. The

photovoltaic system mainly consisted of PV cells, inverter,

controller, accumulator, electric appliance box, and system

load. The PV cells and the evaporating- collector plate were

laminated together to form a PV evaporator module.

Detailed configuration can be found in author’s another

paper about PV-SAHP system (Ji Jie et al., 2007)[3].

The air evaporator and PV evaporator are connected in

parallel. Normally the PV evaporator is in service. At a

time when the solar radiation is weak, and the evaporating

temperature falls below the ambient temperature, then the

air evaporator will start to operate as a booster. The

air-cooled condenser and the water-cooled condenser are

also connected in parallel. The two normally do not operate

simultaneously. When the water-cooled condenser is in

service, the circulating water can indirectly support space

heating and domestic water-heating through individual

heat-exchange devices. The air-cooled condenser on the

other hand is able to directly support space heating when it

is in use, though this part is not modeled in detail in our

present set-up. By changing the positions of the cut-off

valves and the four-way valve, the SAHP system is able to

provide multi-functional services such as space cooling,

space heating and domestic water-heating.

3. TEST METHOD AND PERFORMANCE PARA-

METERS

Frequency of compressor has important impact on system

performance, example: condensing capacity, compression

ratio, COP, phovoltaic/thermal efficiency and others. If the

compressor frequency can match well with the working

conditions as solar radiation etc, the performance of

PV-SAHP system will be done well, otherwise will be done

badly. So for optimization of PV-SAHP system,

performance study under different frequency is necessary.

Two operating modes using 40 Hz and 60 Hz frequency

were processed in the experiments. Experiments were

started at AM10:00 with the water temperature in tank 15 , ć

and stopped when the water temperature was up to 55 . ć

The mass of water in tank was 80kg.The operating

3 SOLAR COLLECTOR TECHNOLOGIES AND SYSTEMS

937

frequency of compressor was changed before each test and

was fixed in one testing process. The expansion valve

changed automatically according to the set frequency.

During the testing period, the average solar irradiance was

733 Wm

-2

and 610 Wm

-2

respectively for compressor

frequency was 40 Hz and 60Hz, while the corresponding

average ambient temperature was 6.5 and 7.7ć . ć

If Q

is the condenser capacity and W

com

the compressor

power, the COP of the PV-SAHP system is given by

COP Q W= (1)

For the water-cooled condenser under test,

)(

winwoutc

TTmcQ −=

(2)

where m is the mass flow rate of the circulating water, c is

the specific heat of water, T

win

and T

wout

are the water

temperatures at the condenser inlet and outlet respectively.

The photovoltaic (cell) efficiency of the PV evaporator is

given by

()WIAη =⋅ (3)

where W

is the output power of the solar cells, I the

incoming solar irradiance, and A the area of solar cells .

4. TEST RESULT AND ANALYSIS

Fig.1 shows that the condensing capacity was obviously on

the high side at the starting period. After about 10 minutes,

it began to descend gradually, and finally it fluctuated

within a certain limit. Though the PV-SAHP system had

operated for some time before test, the temperature of the

PV evaporator was still relatively high at the beginning;

meanwhile, the initial water temperature was relatively low,

so the condenser capacity was obviously on the high side at

the beginning of the test. When the system reached

thermodynamic equilibrium after operating for a period of

time, the variation of the condensing capacity tended to

stabilize. The variation of condensing capacity was

influenced mainly by solar irradiance and condensing water

temperature when the system operated steadily. During the

test, condensing water temperature rose gradually, and the

solar irradiance escalated. Because the variations of the two

factors which two had opposite effect on condensing

capacity, so the condensing temperature fluctuated within a

certain limits without regular rules.

Fig. 1: Variation of condensing capacity.

The compressor power consumption increased with the

increase of compressor frequency, Fig. 2. In the case of

similar weather conditions, an increase of compressor

frequency leaded to a better thermal utility of solar energy

absorbed by the PV evaporator, and a higher condensing

capacity of heat pump. Fig. 1 showed that the average

condensing capacities were 2 421 W and 2 012 W for

compressor frequency at 60Hz and 40Hz respectively, and

the former is higher.

Fig. 2: Variation of compressor power.

COP of PV-SAHP system is an important parameter to

reflect system performance. COP is defined as the quotient

of dividing condenser capacity by compressor power, and

with it, it is effective to compare the performance of heat

Proceedings of ISES Solar World Congress 2007: Solar Energy and Human Settlement

938

pump system of different type and different capacity. The

average COP of PV-SAHP system are 5.4 and 3.7 at

frequency of 40Hz and 60Hz respectively, and the

corresponding maximum can reach 11.0 and 7.5

respectively. Compare with conventional air-sourced heat

pump system, the COP of PV-SAHP system shows a great

improvement. The condensing capacity increases with the

increase of compressor frequency, but for the system COP,

the trend is just the opposite. Fig. 3 shows that at the point

of same time, the system COP at frequency of 40Hz was

obviously higher than the value at frequency of 60Hz. An

increase of compressor frequency leads to a higher

condensing capacity, but meanwhile, a worse system

performance with the system COP declines. In Fig. 2 The

average compressor powers were 423 W and 712 W at

compressor frequency of 40 Hz and 60 Hz respectively, so

an increase of compressor power consumption was an

important factor to the decline of system COP.

Fig. 3: Variation of COP with different time.

Photovoltaic efficiency is influenced by a combination of

factors such as incidence angle of the solar beam,

irradiation intensity and operating temperature of solar cells.

For PV-SAHP system, the PV cell temperature doesn’t rise

so strongly depending on the irradiation as normal PV

panel. It is because the cooling effect of refrigerator

evaporator. So the PV efficiency is influenced mainly by

incidence angle and intensity, showed in Fig. 4, increasing

of PV efficiency according to decreasing of incidence angle

and increasing of radiation with time. On the other hand, an

increase of compressor frequency leads a higher rotate

speed of compressor, and more thermal energy is taken

away by evaporation of refrigerant. The evaporating

pressure and evaporating temperature decline obviously.

The cooling effect is greatly improved and the surface

temperature of evaporator drops. The temperature

characteristic of silicon photovoltaic cell is that: the lower

operating temperature of cells, the higher photovoltaic

efficiency. So the photovoltaic efficiency at 60 Hz is higher

than the value at 40 Hz, as shown in Fig. 4.

Fig. 4: Variation of PV efficiency.

The rise of water temperature leads to the rise of

condensing pressure and condensing temperature. At

compressor frequency of 40 Hz, when the water

temperature rises from 15 to 55ć ,ć the corresponding

condensing pressure rises from 9 atm to 23 atm. With the

rise of condensing pressure, the compression ratio increases

and heat pump is faced with more difficult for energy

transportation. As showed in Fig. 5 , compression ratio

increases from 1.3 to 2.0 with the water temperature rising.

The increase of the compressor power results in a further

decline of the COP.

Fig. 5: Compression ratio with water temperature.

On the other hand, though the rise of condensing

temperature has disadvantageous effect on system, because

of the thermal energy boosted by solar irradiation, the

performance of PV-SAHP also shows well even when the

water temperature is relatively high. While the condensing

temperature rises, the evaporating temperature and the

evaporating pressure also rise because of the solar

3 SOLAR COLLECTOR TECHNOLOGIES AND SYSTEMS

939

irradiation, and this leads to a decrease of the compression

ratio and the difference between evaporating temperature

and condensing temperature, so at frequency of 40Hz, the

system COP can keep more than 3.0 when the water

temperature is near to 55 . ć

5. CONCLUSIONS

Under high compressor frequency mode, the condensing

capacity was improved and the required heating time was

reduced. At the same time, the evaporating pressure and

evaporating temperature was decreased and leaded to a better

photovoltaic and thermal efficiency. Under low compressor

frequency mode, the compressor consumption power and

compression ratio were reduced and the COP of PV-SAHP

was improved. Even in the high water temperature condition,

the performance of system could be maintained a good status

if only enough irradiation. So when the solar irradiation is

low, the PV-SAHP system should operate in a low frequency

to maintain heat pump in a good performance. When the

solar irradiation was sufficient, the frequency of compressor

should be increased to lift more heat to condensing, at the

same time, the PV evaporator could be cooled effectively

and resulted in advantage of photovoltaic and thermal

efficiency of PV evaporator.

6. ACKNOWLEDGMENTS

The work in this paper was sponsored by the NSFC(50478023)

and the NSF of AnHui Province of China (070414161).

7. REFERENCES

(1) F.B.Gorozabel Chata, “Analysis of a direct expansion

solar assisted heat pump using different refrigerants”,

Energy Conversion & Management, Vol. 46, pp.

2614-2624,2005

(2) J.G..Cervantes, “Experiments on a solar-assisted heat

pump and an exergy analysis of the system”, Applied

Thermal Engineering”, Vol. 22, pp.1289-1297, 2002

(3) Ji Jie, Pei Gang, Chow Tin-tai, “Experimental study of

photovoltaic solar assisted heat pump system”, Solar

Energy, doi:10.1016/j.solener.2007.04.006, 2007

(4) Jr.E.C.Kern, “Combined photovoltaic and thermal

hybrid collector system”, Proceedings of the13th IEEE,

Washington DC, USA, pp.1153-1157, 1978

(5) M.N.A. Hawlader and K.A. Jahangeer, “Solar heat

pump drying and water heating in the tropics”, Solar

Energy, Vol. 80(5), pp.492-499,2006

(6) P. Sporn and E.R. Ambrose, “The heat pump and solar

energy”, Proceedings of the World Symposium on

Applied Solar Energy, Phoenix, Arizona, pp. 159-170,

1955

(7) S. Ito and N. Miura, “Heat pump using a solar collector

with photovoltaic modules on the surface”, Journal of

Solar Energy Engineering , Vol. 119, pp.147-151, 1997

EXPERIMENTAL AND PERFORMANCE STUDY OF THE COMPACT SOLAR ABSORPTION

AIR-CONDITIONER SYSTEM WITH THERMOSIPHON SOLUTION ELEVATION PUMP

Cong Lin

Beijing Institute of Technology, Beijing, China, 100081

Zheng Hongfei

Beijing Institute of Technology, Beijing, China, 100081

Li Zhengliang

Guangxi Teacher College, Nanning, Guangxi, China, 530001

Tao Tao

Beijing Institute of Technology, Beijing, China, 100081

ABSTRACT

A new type LiBr adsorption solar air-condition system

with

thermosiphon solution elevation pump is designed, whose

evaporator and absorption tanks are combined in a

circularity, which makes the chill part very compact. On the

basis of theoretical arithmetic, the comprehensive heat

transfer coefficient on the evaporator side and the

theoretical refrigerating capacity are got theoretically. By

experimental study, some useful performance curves are

got, which is significant for optimal design and

improvement. The refrigerating capacity of the system can

be got to be 2.14kW.

1. INTRODUCTION

It is significant on saving energy and protecting the

environment to use inexhaustible solar energy instead of

conventional fuel to drive air-conditioner. Solar air-

conditioner is environmental friendly with no substance

harmful to the atmosphere.

At present, all the countries around the world are studying

the solar air-conditioner. One of the hottest topics is LiBr

absorption air-conditioner. Solution-elevating pump with

multi-lunate channels is used in this system. The

experimental results show that the pump has lower and

wider operation temperature range and run more steadily

and continuously. It can meet the requirement of circulation

of solution in absorption air-conditioning system.

As one of the distinctive characteristics, the uniquely

designed evaporator-absorption tank influence directly on

the performance of the air-conditioner system, in which the

heat and mass transfer process is pretty complex. On the

base of theoretic calculation of the evaporator-absorption

tank, some experiments are completed, and the analysis of

the data is useful for the optimal design.

2 . INTRODUCTION OF THE SYSTEM

As the Fig. 1 shows, the unit is composed of two parts, one

is solar energy collector system, including solar energy

collector, hot water tank, water pump, electric control valve,

and the other is air-conditioner system, made up of

air-conditioner, refrigerated water tank, refrigerated water

pump, valve, tubes and blower. Thin inside construction is

shown in Fig. 2. And the running principle is explained in

the reference[1].

3. CALCULATION OF HEAT TRANSFER COEFFI-

CIENT IN EVAPORATOR-ABSORPTION TANK

3.1 Heat Transfer Coefficient on Evaporator Side

On the Evaporator Side, Falling-film evaporation heat

trans-fer process is composed of three steps: falling-film

Falling-film evaporationˈevaporation on the surface the

tube, conduction of tube wall and the convection inside it.

3 SOLAR COLLECTOR TECHNOLOGIES AND SYSTEMS

941

Fig. 2: Schematic Diagram of the Solar Absorption

Air-conditioner.

1-Hot Water Entry; 2-Solution Tank; 3- Chilling Water Exit;

4-Evaporator-Absorption Tank; 5- Chilling Water Entry; 6-Hot Water Exit;

7- Cooling Water Exit; 8- Cooling Tank; 9- The Distilled Water Tube;

10-Concentrated Solution Pipe; 11- Cooling Water Entry;

12- Solution Elevation Pump

heat transfer coefficient is computed by the formula (1):

Re Pr

⎛⎞

⎜⎟

⎝⎠

˄1˅

In which, the fluid thermal conductivity of the falling film

, the kinematics viscosity v

, the solution spray rate Г, The

Re number, const aǃthe Pr number are computed according

to the experimental data. The falling-film evaporation heat

transfer coefficient is:

out

= 3714.946 W/(m

gk)

The tube is made of cooper, so the thermal conductivity of

the tube wall is:

= 393 W/(m·K)

The convective heat transfer coefficient inside the tube is

calculated by the convection theory, which is:

= 2319.38 W/(m

gk)

The comprehensive heat transfer coefficient is calculated

sun light

cool air

Fig. 1: Schematic diagram of the absorption solar conditioner unit.

1-Circulating Pump; 2-Solar Energy Collector; 3-By Pass Pump No.1; 4-By Pass Pump No.2; 5-Hot Water Tank; 6-Cooling Water Tank; 7-Cooling Water Pump;

8 Hot Water Pump; 9-Air-conditioner; 10-Refrigration Water Tank; 11-Refrigration Water Tank; 12- Blower; 13-Room

Труды Всемирного конгресса Международного общества солнечной энергии - 2007. Том 2

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