Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads
The study presented in this paper describes the experimental rig and the methodology used to carry out the experimental research for an absorption refrigeration system operating in partial heat loads. The refrigeration performance, was analysed using a nominal thermal load (100%) and two partial loa...
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| Date: | 2005 |
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Інститут технічної теплофізики НАН України
2005
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| Cite this: | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads / I. Carvajal, G. Polupan, F. Sanchez, P. Quinto, A. Zacarias // Промышленная теплотехника. — 2005. — Т. 27, № 5. — С. 58-65. — Бібліогр.: 7 назв. — рос. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1860089824719929344 |
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| author | Carvajal, I. Polupan, G. Sanchez, F. Quinto, P. Zacarias, A. |
| author_facet | Carvajal, I. Polupan, G. Sanchez, F. Quinto, P. Zacarias, A. |
| citation_txt | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads / I. Carvajal, G. Polupan, F. Sanchez, P. Quinto, A. Zacarias // Промышленная теплотехника. — 2005. — Т. 27, № 5. — С. 58-65. — Бібліогр.: 7 назв. — рос. |
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| container_title | Промышленная теплотехника |
| description | The study presented in this paper describes the experimental rig and the methodology used to carry out the experimental research for an absorption refrigeration system operating in partial heat loads. The refrigeration performance, was analysed using a nominal thermal load (100%) and two partial loads of 60% and 80% and two overloads of 120% and 140%.
В роботі дано опис експериментального обладнання і методики, що використовувалися для отримання даних на абсорційній холодильній системі при різних теплових навантаженнях. Холодильні характеристики були проаналізовані при номінальному тепловому навантаженні (100%), а також при двох знижених навантаженнях (60% і 80%) і двох підвищенних теплових навантаженнях (120% и 140%).
В исследовании, представленном в статье, описана экспериментальная установка и методика, использованные для получения экспериментальных данных на абсорбционной охладительной системе при разных тепловых нагрузках. Холодильные характеристики были проанализированы при номинальной тепловой нагрузке (100%), а также двух пониженных нагрузках (60% и 80%) и двух повышенных тепловых нагрузках (120% и 140%).
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1. Introduction
Due to the energy conservation and the operating
cost reduction, the thermal energy recovery from
exhaust gases and combustion products is getting
common in several industries. One of the alternatives
for this purpose is the so called absorption refrigera;
tion systems. This is because the temperature require;
ments for that cycle falls into the low;temperature
(lower than 230 оC) waste heat recovery range [1],
where a significant potential for electrical energy sav;
ing exists.
58 ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
В роботі дано опис експериментально)
го обладнання і методики, що використо)
вувалися для отримання даних на абсор)
ційній холодильній системі при різних
теплових навантаженнях. Холодильні ха)
рактеристики були проаналізовані при
номінальному тепловому навантаженні
(100%), а також при двох знижених наван)
таженнях (60% і 80%) і двох підвищенних
теплових навантаженнях (120% и 140%).
Холодильна видатність абсорбційної сис)
теми при тепловому навантаженні 120%
підвищувалась на 30% по відношенню до
номінального навантаження і в подальшому
понижувалася більш ніж на 50% при підви)
щенному тепловому навантаженні в 140%.
Найбільш низьке значення коефіцієнта ви)
користання було отримане для теплового
навантаження 140% і склало тільки 0,04.
Для інших досліджених теплових наванта)
жень цей коефіцієнт знаходився в межах
від 0,15 до 0,22 при його номінальному
значенні 0,19.
В исследовании, представленном в
статье, описана экспериментальная уста)
новка и методика, использованные для
получения экспериментальных данных на
абсорбционной охладительной системе
при разных тепловых нагрузках. Холо)
дильные характеристики были проанали)
зированы при номинальной тепловой на)
грузке (100%), а также двух пониженных
нагрузках (60% и 80%) и двух повышен)
ных тепловых нагрузках (120% и 140%).
Холодильная производительность аб)
сорбционной установки при тепловой на)
грузке в 120% возрастала на 30% по от)
ношению к номинальной нагрузке и
далее снижалась более чем на 50% при
повышенной тепловой нагрузке в 140%.
Наиболее низкое значение коеффициен)
та использования было получено для
тепловой нагрузки 140% и составило
только 0,04. Для других исследованных
тепловых нагрузок этот коэффициент на)
ходился в пределах от 0,15 до 0,22 при
его номинальной величине 0,19.
The study presented in this paper
describes the experimental rig and the
methodology used to carry out the experi)
mental research for an absorption refriger)
ation system operating in partial heat
loads. The refrigeration performance, was
analysed using a nominal thermal load
(100%) and two partial loads of 60% and
80% and two overloads of 120% and
140%. The refrigeration capacity respect
the nominal, was increased up to a 30 % for
the overload of 120 % and decreased more
than 50 % for the partial load of 60 % and
overload of 140%. The lower value of the
Coefficient of Performance was obtained
for the overload of 140% being of only
0,04. For the other partial loads and over)
loads it was located in the range of 0,15 to
0,22 being its nominal value of 0,19.
УДК 621.1.016.4
I. CARVAJAL, G. POLUPAN, F. SANCHEZ,
P. QUINTO, A. ZACARIAS
Thermal Hydraulics Applied Engineering Laboratory, National Polytechnic Institute of Mexico
HEAT TRANSFER STUDY IN THE ELEMENTS OF AN
ABSORPTION REFRIGERATION SYSTEM OPERATING IN
PARTIAL HEAT LOADS
A – Surface area;
b – Fin pitch;
Cp – Water heat capacity;
d – Tube diameter;
g – gravity force;
h – Convective coefficient;
k – Thermal conductivity;
L – Fin length;
– Water mass flow rate;
PE – Electrical power;
Q – Heat flow;
R1, R2 – Electrical resistances;
T – Temperature;
VE – Voltage.
α – Thermal diffusivity;
β – Volumetric thermal;expansion coefficient;
v – Cinematic viscosity;
wm
The absorption refrigeration systems are used to
rise temperatures up to 9 оC for bromide lithium
machines and –5 оC for ammonia machines [2].
Both types of systems can be used in industrial
applications.
The absorption refrigeration system operation can
be found in the technical literature, such as the
ASHRAE Transactions [3]. The main advantages of
using absorption refrigeration systems for waste heat
recovery can be attributed to [4]:
Their quiet operation;
Their ability to produce cooling by using hot
gases, process steam, process liquids/solids, and
exhaust air;
Their little service or maintenance requirement;
Their simplicity;
Their reliability.
To apply the absorption refrigeration systems for
waste heat recovery, it is necessary to know their ther;
mal performance when the systems operate with par;
tial heat loads. These kind of situation occur due to
the variation of the hot gases flow characteristics
(from incinerators, furnaces, and so on), during the
thermal energy supply to the boiler.
In this study the thermal performance of the
absorption refrigeration system with partial heat loads
to the boiler was carried out experimentally and the
results were compared with the nominal heat load of
the system.
2. Experimental rig
The experimental rig used for the absorption
refrigeration process was an absorption refrigeration
system which was taken from a small commercial
refrigerator with 90 dm3 of internal volume and a
freezing compartment of 5 dm3.
Figure 1 shows the schematic diagram of the
absorption system. The unit charge consist of a 0.40
kg of ammonia, water and hydrogen. These are at a
sufficient pressure to condense ammonia at room
temperature. From the Fig. 1 it can be observed that
in this type of absorption refrigeration systems there
are no moving parts.
Figure 2 shows a photograph of the main com;
ponents of the experimental rig. These components
include the boiler (cover with insulating material),
the condenser, the evaporator and the absorber.
The evaporator is supplied with hydrogen. The
hydrogen passes across the surface of ammonia. It
lowers the ammonia vapor pressure enough to allow
the liquid ammonia to evaporate. The hydrogen
circulates continuously between the absorber and
the evaporator.
The thermal energy supplied to the boiler was pro;
vided from two electrical resistances of 95 .each one,
connected in parallel. To supply the electrical current
a potentiometer was used. It operates at 127 V with a
regulation range of 0-100%.
The experimental system was provided with eight
thermocouples, type T (± 0.1оC accuracy), along the
system as is illustrated by dots in Fig. 1. The thermo;
couples were connected to a data acquisition system,
using the commercial software Scan Link® 2.0, to
record the measured temperatures.
The temperatures along the system were recorded
every 5 minutes for an interval of four hours. Three
experimental tests were carried out for each load: one
nominal, two partial loads and two overloads.
In order to supply the refrigeration process load a
cylindrical container was installed outside the evapo;
rator, through that container, water was circulated,
transmitting heat to the liquid ammonia, which circu;
lated inside along the evaporator.
ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5 59
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
Fig. 1. Schematic diagram of the absorption
refrigeration system.
The water flow rate was measured using a rotame;
ter, which was calibrated for a range of 0 to 1 l/min
flow rate. The water flow rates were adjusted by valves
at the inlet and the outlet of the cylindrical container.
A pump was used to provide sufficient pressure to cir;
culate the water through the cylindrical container. The
pump used had a 373 W motor and had a maximum
capacity of 11.35 l/min. The volumetric flow rate was
maintained the same for each test: 0.25 l/min.
In order to reduce the heat loss from the boiler,
fiberglass of thickness of 25.4 mm and an aluminum
coating was used to insulate the piping. To avoid the
evaporator gain heat from the surroundings, the evap;
orator piping was insulated with polyurethane.
Based on the Joule’s Law and the electrical resist;
ances values, the voltage and its correspondent cur;
rent for the nominal and partial loads were deter;
mined. The Joule’s Law is expressed by:
. (1)
The input data of the heat load of boiler was differ;
ent for the nominal and each four partial loads (see
Table 1).
The measurement errors of the different
parameters was estimated to be approximately of
8%. The standard deviation of the experimental
data was ± 6%.
Table 1
3. Energy balance of the system
components
A computational program was developed to calcu;
late the parameters obtained from the energy balance
for each component of the system using the experi;
mental data as input data. The equations to calculate
the energy balance for each component are:
Boiler
To calculate the heat flow supply to the boiler, the
power of the electrical resistances was considered by
using the expression [5]:
, (2)
where: , is the boiler average temperature and Tout,bis
the surrounding temperature; h, is the natural;convec;
tion coefficient of a vertical tube (the boiler) [5].
Evaporator
To determine the heat flow in the evaporator the
following equation was used [5]:
, (3)
where: Tin, is the water inlet temperature and Tout, is
the water outlet temperature of cylindrical container.
Condenser
The condenser has a square;finned tube and a
plain tube (see Fig. 2). To calculate the heat flow in
the condenser, the total heat rejected in the finned
tube and in the plain tube were considered as follows:
Qc = Qplaintube + Qfinnedtube . (4)
For these calculations, the square;finned tube and
the plain tube, were analysed separately using the cor;
responding expressions from [6]:
square;finned tube
( )e w p in outQ m C T T= −
( bT
( )b bQ hA T T∞= −
1 2
1
1 1E EV P
R R
= ⋅
+
60 ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
Fig. 2. Photograph of the experimental rig.
,
where m = 2.7 for air
Qfinnedtube =hft Aft ΔT
plain tube
Qplaintube = hpt Apt ΔT
Tw – is the wall temperature.
Absorber
The heat flow at the absorber was calculated by a
energy balance through the all system using the fol;
lowing expression:
Qin = Qout + Qloss , (5)
where: Qin, is the inlet system heat flow, Qout, is the
outlet system heat flow and Qloss, are the system heat
losses to the surroundings.
Therefore, we can write a heat balance,
Qg + Qe = Qa + Qc + Qloss (6)
and
Qa = Qg + Qe – Qc – Qloss . (7)
The system heat losses to the surroundings Qloss
was estimated in [3], to be between 5 and 10%. In this
research the estimation of the heat losses were
approximately about 8%.
4. Results and discussion
The experimental heat flows for each component,
were plotted as a function of the time. The average val;
ues of the partial loads investigated were also plotted.
Figures 3, 4, 5, 6 and 7 show the performance of the
refrigeration system with five different thermalloads
supplied to the boiler that is, 60%, 80%,100%, 120%
and 140%. It was observed that for all tests, the refrig;
eration process reached the steady performance
approximately after two hours of continuous operation.
Figure 3 illustrates the performance of eachrefrig;
eration system component with nominal heat load of
100% (by design or specification) and it can be
observed that for the first 15 minutes of operation the
heat supplied to the boiler was approximately similar
to the heat dissipated by the absorber. At the same
time, the amount of heat dissipated by the water in the
evaporator is cero. The same occur in the condenser,
where the heatdissipated is zero.
The results confirm that the separation and
absorption processes of the refrigerant are notefficient
at the beginning of the performance of the system.( )
pt pt
pt
w
Nu k q d
h
b T T k∞
′′
= =
−
v
Pr =
α
( ) 3
w
pt
g T T d
Ra
v
∞β −
=
α
2
1/6
8/ 27
9/16
0.387
0.60
0.559
1
pt
pt
Ra
Nu
Pr
⎧ ⎫
⎪ ⎪
⎪ ⎪⎪ ⎪= +⎨ ⎬
⎡ ⎤⎪ ⎪⎛ ⎞+⎢ ⎥⎪ ⎪⎜ ⎟⎝ ⎠⎢ ⎥⎪ ⎪⎣ ⎦⎩ ⎭
( )
ft ft
ft
w
Nu k q b
h
b T T k∞
′′⎛ ⎞
= = ⎜ ⎟⎜ ⎟−⎝ ⎠
( ) 3
w
ft
g T T b b
Ra
v L
∞β − ⎛ ⎞= ⎜ ⎟α ⎝ ⎠
( )
1/
0.89
1/ 4
0.62
18
m
m
mft
ft ft
Ra
Nu Ra
⎡ ⎤⎛ ⎞
⎢ ⎥= +⎜ ⎟⎜ ⎟⎢ ⎥⎝ ⎠⎣ ⎦
ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5 61
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
Fig. 3. Heat flow gained/dissipated for the components
of the system as a function of the time, with a nominal
load (100%).
This is, because the heat flow supplied to the boiler is
not sufficient. For the same reason, the refrigerant
flow is not sufficient to cool the refrigeration load.
After 20 minutes of the system operation it is start;
ing to carry out the refrigeration process.
Figure 4 shows the system operation with a thermal
partial load of 60% supplied to the boiler. It can be
seen that after 40 minutes of the system operation, the
refrigeration process starts.
In the evaporator, the refrigeration rate was about
50% lower in comparison with nominal load test.
In the interval of 30 to 50 minutes, there was insta;
bility of the system operation. This was because the
refrigerant flow was very low. Therefore, the absorp;
tion process was very slow also. As result, the mixed
flow flowing to the boiler is also less.
The instability of the process occurred because at
the same interval of time, the evaporation process
required a greater amount of refrigerant, and for this
reason, the mass flow rate passing through the
absorber and going toward the boiler was reduced.
Figure 5 shows the 80 % thermal partial load to the
boiler. It is possible to observe that the cooling effect
is evident 25 minutes after the starting, and the cool;
ing capacity of the evaporator increases in function of
the exhausted heat in the condenser. Additionally it is
possible to see that the heat dissipated in the absorber
was reduced instead of increased, is in spite of the
increase of the heat flow supplied to the boiler. All this
indicate that the equipment tends to have a nominal
behavior where the heat flows in the condenser and in
the absorber as well should have almost the same value
and at the same average temperature.
Figure 6 shows the system performance with a
greater load than the nominal load of 120%, supplied
to the boiler.
From figure 6 it can be observed that after 15 min;
utes of system operation, the refrigeration process
starts. It is possible to remark that the refrigeration
rate of the evaporator was approximately of 30% high;
er than the one for the nominal load.
In view that the boiler was supplied heat, the
absorber and the condenser dissipated a great amount
of heat. In this case there were any instabilities before
the evaporator starts cooling the water. Additionally
the heat flow in the absorber started to decrease dras;
tically until the case where it was lower than in the
condenser. After this radical change, all heat flows
tended to be stable.
The 140 % thermal overload to the boiler case is
shown in figure 7. The refrigeration process started 15
62 ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
Fig. 4. Heat flow gained/dissipated for the components
of the system as a function of the time, with partial
load of 60%.
Fig. 5. Heat flow gained/dissipated for the components
of the system as a function of the time, with partial
load of 80%.
Fig. 6. Heat flow gained/dissipated for the components
of the system as a function of the time, with a partial
load of 120%.
minutes after the system was turned in. Additionally,
the heat flow in the condenser was much higher than
in the absorber and the heat flow in the evaporator
stopped increasing as in the previous cases, on the
contrary it was much lower that in the 60 % load test.
The excess of heat supplied to the boiler produced,
as a result, that a great quantity of vapor ammonia
were delivered directly to the condenser and this can
not transform all vapor into liquid, because is limited
by the convective coefficient h and the surface area A.
The liquid transformed part was sent to the evapora;
tor where it performed the environment cooling in a
very poor manner. The other quantity of ammonia
which was not able to condense was directed to the
absorber, where due to the poor absorption by the
weak solution for its high temperature, a stagnant
zone of the gas was created, that is, the working fluid
circulation was restrained in the system. As a result, is
not recommended to operate the system with an
excess of heat supplied to the boiler of 40 %.
After the analysis of different loads supplied to the
boiler, we can conclude that it is very important to know
the heat transmission to each element of the system.
The boiler is the element which receives the heat
supply and for this reason its operation has a signifi;
cant influence in the whole system performance.
In figure 8, is shown that the heat transfer behav;
iour in the boiler for different partial loads is similar.
That is due to the use of electrical resistance for the
heat supply, the voltage was kept constant for each
test, then the variation only occurred while the heat;
ing was transient because in steady state the variation
was very insignificant during the experimentation.
The condenser has a very important role in the cor;
rect operation of the evaporator and in the absorption
system in general. Figure 9 shows how the heat reject;
ed to the surroundings was increasing according to the
heat flow supplied to the boiler. For this reason, it is
clear the important difference we can see in the heat
flow figures at overload of 120 % and in the nominal
load (100 %). It is more notorious if this difference is
compared among the overloads of 120 % and 140 %.
The evaporator is the element determining the
cooling system capacity, so that it is very important to
analyze the results obtained for this element.
In figure 10, the heat transfer behaviour in the
evaporator is shown. We can remark that the heat flow
in the evaporator increases since the very moment the
refrigeration process starts until the moment when
tends to be constant. For the overload of 120 % the evap;
orator has a refrigeration capacity higher that 30 % than
for the nominal load. While for partial load of 60 %
and overload of 140 % the refrigeration capacity
ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5 63
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
Fig. 7. Heat flow gained/dissipated for the components
of the system as function of the time, with part load of
140%.
Fig. 9. Heat flow dissipated by the condenser as
function of the time, for different part loads.
Fig. 8. Heat flow supply to boiler as function of the
time, for different part loads.
diminishes more than the 50 %, so that it is not rec;
ommended to operate the absorption refrigeration
system in this two loads.
The behaviour of the absorber has much to do with
the efficient stabilization and operation of the system.
In figure 11 the heat transfer behaviour in the
absorber is shown, which resulted to be the most
complex of all here showed.
During the partial loads of 60 %, 80 % and the
nominal, the heat dissipation in the absorber has a
behaviour practically stable which corresponds with
the heat flow supplied to the boiler. On the contrary
for the partial load of 120 %, the maximum in heat
dissipation is attained 30 minutes after, following a
stabilization in a value near to the one obtained for
the nominal load.
For the overload of 140 % this maximum is pre;
sented 20 minutes after the beginning of the process.
However, differently to the anterior case, the heat dis;
sipation decreases drastically until values inferior to
the ones presented for the nominal loads and 80 %
and is lightly superior to the one presented with the
partial load of 60%.
After the analysis of the refrigeration system
behavior operating in partial loads and the heat trans;
fer in its different elements, it is possible to remark
that the system operates steadily and with satisfactory
values in the refrigeration process in the loads range of
80% to 120 %, being recommended that the system
operates the most of the time, up of its nominal load.
To validate completely this information it is neces;
sary to calculate the coefficient of performance.
5. Coefficient of performance
The figure of merit adopted in cooling engineering
is the useful effect divided by the input power, defined
as the Coefficient of Performance, or COP for short.
For the chiller mode of operation (cooling or
refrigeration at the evaporator) of the absorption
machine, the COP is [7]:
The COP of absorption systems is ostensibly far
lower than that of the corresponding mechanical
devices. The key advantage of absorption technology
lies in the direct utilization of locally;available ther;
mal sources.
In the figure 12, the curves of the coefficient of
performance computed for two partial loads, two
overloads and the nominal are shown. In this figure it
is possible to observe that the COP for the partial load
from 60 % to overload of 120 % are in the range of
0.15 to 0.22, being its nominal value of 0.19. It is
important to take into account also the beginning of
the refrigeration process since for the 120 % overload
was only of 15 minutes while for the 60 % partial load
was of 35 minutes.
On the other hand, for the overload of 140 % the
obtained values are much lower of the ones obtained
for the nominal load, in the order of 0.04. All this yields
to affirm that it is possible to operate the absorption
refrigeration system, studying the range of partial loads
cooling rate
COP
thermal power input
heat transfer at the evaporator
heat input at the generator
= =
=
64 ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
Fig. 10. Evaporator refrigeration capacity as function
of the time, for different part loads.
Fig. 11. Heat flow dissipated by the absorber as func<
tion of the time, for different part loads.
from 60 % to 120%, being preferable that the most of
the time be working over the nominal load which is
where the higher COP values were obtained. However
the limit of this overload must be considered of 120 %
because as we have seen previously instead of having an
increment of the COP this decreases drastically.
Conclusions
From the experimental data obtained we can
deduce the following conclusions:
For all the overloads and partial loads including the
nominal, the system attains its steady operation
approximately in two hours after the beginning of the
thermal energy supply to the boiler. The refrigeration
process starts since the 15 to the 35 minutes, for the
loads of 120% to 60% respectively being the nominal
value of 20 minutes.
The refrigeration capacity respect the nominal,
was increased up to a 30 % for the overload of 120 %
and decreased more than 50 % for the partial load of
60 % and overload of 140%.
Some instabilities were detected in the operation of
the absorber for all the partial loads and overloads,
being the more notorious the ones observed for the
overloads of 120 % and 140 %.
The lower value of the Coefficient of Operation
was obtained for the overload of 140% being of only
0.04. For the other partial loads and overloads it was
located in the range of 0.15 to 0.22 being its nominal
value of 0.19.
For all the above exposed, we can affirm that it is
possible to operate the absorption refrigeration system
studied in the partial loads range of 60 % to overload
of 120 % being preferable that the most of the time
works above the nominal load where the largest values
of COP were obtained. However the limit of this over;
load must be fixed in 120 %, because if we apply a big;
ger load as we have seen, instead of having an incre;
ment of COP it decreases drastically.
Acknowledgement
The authors wish to acknowledge the support of The
National Polytechnic Institute of Mexico to undertake
the present project.
REFERENCES
1. Kreith F. and West R. E., “CRC handbook of
energy efficiency”, CRC Press, Inc. (1997).
2. Rapin P. and Jacquard P, “Formulaire du
froid”, Dunod, Paris (2001).
3. “Absorption cooling, heating and refrigeration
equipment”, ASHRAE Trans Vol. 89 (1994).
4. Anderson E. P., “Refrigeration: Home and
commercial”, Macmillan Publishing (1990).
5. Guyer E. C. and Brownell D.L., “Handbook of
applied thermal design”, Mc Graw Hill (1996).
6. Incropera F., “Fundamentals of heat trans;
fer”, Pearson Education (1999).
7. Gordon J. M. and Ng K. Ch., “Cool thermody;
namics”, Cambridge International Science
Publishing (2000).
Получено 04.05.2005 г.
ISSN 0204�3602. Пром. теплотехника, 2005, т. 27, № 5 65
ТЕПЛО) И МАССООБМЕННЫЕ АППАРАТЫ
Fig. 12. Coefficient of performance COP of the
absorption refrigeration system as a function of the
time, for different partial loads.
|
| id | nasplib_isofts_kiev_ua-123456789-61479 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0204-3602 |
| language | English |
| last_indexed | 2025-12-07T17:22:23Z |
| publishDate | 2005 |
| publisher | Інститут технічної теплофізики НАН України |
| record_format | dspace |
| spelling | Carvajal, I. Polupan, G. Sanchez, F. Quinto, P. Zacarias, A. 2014-05-06T11:59:16Z 2014-05-06T11:59:16Z 2005 Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads / I. Carvajal, G. Polupan, F. Sanchez, P. Quinto, A. Zacarias // Промышленная теплотехника. — 2005. — Т. 27, № 5. — С. 58-65. — Бібліогр.: 7 назв. — рос. 0204-3602 https://nasplib.isofts.kiev.ua/handle/123456789/61479 621.1.016.4 The study presented in this paper describes the experimental rig and the methodology used to carry out the experimental research for an absorption refrigeration system operating in partial heat loads. The refrigeration performance, was analysed using a nominal thermal load (100%) and two partial loads of 60% and 80% and two overloads of 120% and 140%. В роботі дано опис експериментального обладнання і методики, що використовувалися для отримання даних на абсорційній холодильній системі при різних теплових навантаженнях. Холодильні характеристики були проаналізовані при номінальному тепловому навантаженні (100%), а також при двох знижених навантаженнях (60% і 80%) і двох підвищенних теплових навантаженнях (120% и 140%). В исследовании, представленном в статье, описана экспериментальная установка и методика, использованные для получения экспериментальных данных на абсорбционной охладительной системе при разных тепловых нагрузках. Холодильные характеристики были проанализированы при номинальной тепловой нагрузке (100%), а также двух пониженных нагрузках (60% и 80%) и двух повышенных тепловых нагрузках (120% и 140%). The authors wish to acknowledge the support of The National Polytechnic Institute of Mexico to undertake the present project. en Інститут технічної теплофізики НАН України Промышленная теплотехника Тепло- и массообменные аппараты Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads Исследование теплопередачи в элементах абсорбционных охладительных систем при различных тепловых нагрузках Article published earlier |
| spellingShingle | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads Carvajal, I. Polupan, G. Sanchez, F. Quinto, P. Zacarias, A. Тепло- и массообменные аппараты |
| title | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads |
| title_alt | Исследование теплопередачи в элементах абсорбционных охладительных систем при различных тепловых нагрузках |
| title_full | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads |
| title_fullStr | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads |
| title_full_unstemmed | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads |
| title_short | Heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads |
| title_sort | heat transfer study in the elements of an absorption refrigeration system operating in partial heat loads |
| topic | Тепло- и массообменные аппараты |
| topic_facet | Тепло- и массообменные аппараты |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/61479 |
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