Absorption type cooling and heating system

An absorption type cooling and heating system including a generator, an outdoor heat exchanger, pressure reducing devices, two indoor heat exchangers, an absorber, a solution pump, change-over valves, on-off valves and check valves, wherein in a cooling mode the outdoor heat exchanger functions as a condenser and the two indoor heat exchangers function as evaporators and in a heating mode one of the two outdoor heat exchangers functions as a condenser, the other outdoor heat exchanger functions as an absorber and the outdoor heat exchanger and the absorber function as evaporators, so that the heat of a refrigerant in a gaseous state of high temperature and the heat of absorption generated at the absorber can both be utilized as heating heat sources. In a defrosting mode, the outdoor heat exchanger and the absorber function as condensers and one of the two indoor heat exchangers functions as an absorber, so that space heating can be carried out even during the defrosting mode.

BACKGROUND OF THE INVENTION 
This invention relates to a cooling and heating system using a 
refrigerating apparatus of the absorption type. 
Absorption type refrigerating apparatus use thermal energy as an energy 
source. In recent years, a cooling and heating system of the gas burning 
absorption type has come to attract attention, in view of the fact that a 
demand for electric power in the summertime has reached a peak load level 
due to popularization of electric cooling systems, and with a view to 
switching the energy source from oil to natural gas. 
There are available a variety of combinations of a refrigerant and an 
absorbing agent used with absorption type refrigerating apparatus. The 
combinations that have been put to practical use include water and lithium 
bromide, ammonia and ammonia water, and Fron (CHCIF.sub.2) and 
tetraethyleneglycol dimethylether (CH.sub.3 O(CH.sub.2 CH.sub.2 O).sub.4 
CH.sub.3), for example. 
A gas burning absorption type cooling and heating system of the prior art 
referred to hereinabove includes in the refrigeration cycle a generator, a 
condenser, pressure reducing means, an evaporator, an absorber and a 
liquid pump as basic components. A heat source of a refrigerant of high 
temperature heated and separated at the generator serves as a heating heat 
source, and a latent heat source generated at the evaporator serves as a 
cooling heat source. This type of cooling and heating systems are 
disclosed in U.S. Pat. Nos. 3,527,061 and 3,638,452 to Roy W. Kruggel et 
al, U.S. Pat. No. 4,207,751 to Ottomar Kampfenkel et al. and Japanese 
Patent Application Laid-Open No. 53052/78 (Shozo Saito), for example. U.S. 
Pat. No. 3,527,061 contemplates performing a cooling and heating operation 
by switching the system between cold water and heated water circuits 
without effecting change-over of the refrigerant circuit. The refrigerant 
of elevated temperature separated at the generator is condensed into a 
liquid state at the condenser and fed to the evaporator after passing 
through the temperature type automatic expansion valve for pressure 
reduction and expansion, so as to cool the water flowing through the 
evaporator. In a cooling mode, the cooled water is supplied through a 
water channel change-over valve to a heat exchanger mounted in a spaced to 
be cooled, where heat exchange takes place between the water and air 
forcedly fed to the heat exchanger by a blower to cool the air. In a 
heating mode, the hot water flowing through the condenser is supplied 
through the water channel change-over valve to the heat exchanger mounted 
in the space to be heated, to effect heating of the space by heating air 
with the hot water. During the heating mode, frost formation takes place 
in an outdoor heat exchanger, when the operation is performed over a 
prolonged period. Defrosting can be carried out, however, by temporarily 
switching the water channel to a cooling operation. 
In U.S. Pat. No. 3,638,452, no switching of the refrigerant circuit and the 
water circuit is effected and cooling and heating operations are performed 
by using cold water and hot water respectively. The refrigerant of 
elevated temperature separated at the generator is changed into a liquid 
stated by condensation at the condenser and supplied to the evaporator 
after having its pressure reduced by expansion, to cool the water flowing 
through the evaporator for use as a cooling heat source. For a heating 
heat source, the absorber, condenser and generator are formed into a water 
circuit for producing hot water. 
In U.S. Pat. No. 4,207,751, no change-over of the refrigerant circuit is 
effected and a refrigerant is directly supplied, in a cooling mode, to a 
heat exchanger mounted in a duct leading to a space to be cooled, to 
directly cool the air. In a heating mode, the heat generated at the 
condenser and absorber is recovered through a hot water circuit, so as to 
provide a heating heat source. 
Japanese Patent Application Laid-Open No. 53052/78 relies on the 
change-over of the refrigerant circuit for producing cold water and hot 
water for performing cooling and heating operations. In a cooling mode, 
the water cooled at the evaporator is used as a cooling heat source, and 
in a heating mode the evaporator is made to function as an absorber and an 
absorber is made to function as an evaporator, by switching the 
refrigerant circuit in some parts thereof. 
Thus the cooling and heating systems using absorption type refrigerating 
apparatus of the prior art can be broadly classified into three types: one 
type produces cold water and hot water to provide heat sources for cooling 
and heating operations without effecting change-over of the refrigerant 
circuit; another type performs a cooling operation in a direct expansion 
system by causing heat exchange to take place between air and a 
refrigerant through a heat exchanger, and a heating operation by producing 
hot water by utilizing heat of absorption and heat of condensation, to use 
the hot water as a heating heat source; and still another type relies on 
the change-over of the refrigerant circuit to produce cold water and hot 
water, to make them serve as cooling and heating heat sources. 
Generally, when a heat exchanger of the air cooling type is used, it is 
necessary to carry out defrosting in a heating mode because of frost 
formation. When defrosting is carried out, the system may be temporarily 
switched from the heating operation to a cooling operation as described in 
U.S. Pat. No. 3,527,061 referred to hereinabove. However, this process 
suffers the disadvantage that cold water is supplied to the indoor heat 
exchanger during a defrosting operation and the air in a space to be 
heated is temporarily cooled, so that the cold air ejected into the space 
makes people unpleasant and uncomfortable. To minimize the cold air blown 
into the space to keep the people from becoming uncomfortable, the number 
of revolutions of the blower may be decreased, the blower may be rendered 
totally inoperative or an auxiliary heat source, such as an electric 
heater, may be utilized to heat the ejected cold air, in a cooling and 
heating system of the air cooling heat pump type which uses a compressor. 
In some other cooling and heating systems of the compression type, a 
heating operation may be performed by using a plurality of heat exchangers 
while performing defrosting through one of the heat exchangers. This type 
has the disadvantage that it has a large size and the system becomes large 
in capacity, and the principle of operation cannot be incorporated in a 
system of small capacity. 
Meanwhile heating and cooling systems of the water heat source and water 
cooling type would not satisfy the social needs because the water 
resources are running scarce and strict limitations are placed on their 
use. 
In view of the foregoing, it is necessary that even an absorption type 
cooling and heating system be constructed as a heat pump type system of 
the air heat source and air cooling type, to meet the requirement of 
energy conservation. 
SUMMARY OF THE INVENTION 
An object of this invention is to provide a heat pump type cooling and 
heating system which is high in performance and capable of contributing to 
energy conservation. 
Another object is to provide a heat pump type cooling and heating system 
with an air heat source capable of performing defrosting of an outdoor 
heat exchanger while performing a heating operation in a heating mode. 
Still another object is to provide a heat pump type cooling and heating 
system with an air heat source suitable for using a Fron base or ammonia 
base refrigerant of high pressure. 
To accomplish the aforesaid objects, there is provided an absorption type 
cooling and heating system comprising an outdoor heat exchanger and two 
indoor heat exchangers, wherein in a cooling mode, the path of a 
refrigerant is switched by means of a change-over valve to enable the 
outdoor heat exchanger to act as a condenser while allowing the two indoor 
heat exchangers to function as evaporators by switching the path of the 
refrigerant by means of another change-over valve; in a heating mode, the 
path of the refrigerant is switched by means of the two change-over valves 
to enable one of the indoor heat exchangers and the other indoor heat 
exchangers to act as a condenser and an absorber respectively while 
allowing the outdoor heat exchanger and the absorber to function as 
evaporators; and in a defrosting mode, the path of the refrigerant is 
switched by means of the change-over valves to enable the outdoor heat 
exchanger and the absorber to act as condensers while allowing one of the 
indoor heat exchangers to function as an absorber. 
The outstanding characteristics of the invention are that in a system 
comprising a basic circuit including a generator, an absorber, an outdoor 
heat exchanger and two indoor heat exchangers, a path on the refrigerant 
side and a path on the solution side are switched by means of change-over 
valves to enable the outdoor heat exchanger to function as a condenser in 
a cooling mode, as an evaporator in a heating mode and as a condenser in a 
defrosting mode; the two indoor heat exchangers are allowed to function as 
evaporators in a cooling mode and as a condenser and an absorber in a 
heating mode while one of them is allowed to function as an absorber and 
the other indoor exchanger is rendered inoperative in a defrosting mode; 
and the absorber is allowed to function as an absorber in a cooling mode, 
as an evaporator in a heating mode and as a condenser in a defrosting 
mode. 
One of the novel features of the invention is that the system can perform 
defrosting without losing the overall heating capabilities. More 
specifically, one of the two indoor heat exchangers is allowed to function 
as a condenser and the outdoor heat exchanger and the absorber are both 
allowed to function as evaporators in a heating mode. However, frost 
formation may occur as the heating mode continues. To effect defrosting, 
the path of the refrigerant is switched by means of the change-over valve 
to allow the refrigerant of high temperature to flow to the evaporator. 
After melting the frost on the surface of the evaporator, the refrigerant 
flowing out of the evaporator is joined to a diluted solution (a solution 
containing no refrigerant) separated from the refrigerant at the 
generator, to flow into one of the two indoor heat exchangers to perform 
absorption. The heat dissipated as the result of the absorption is ejected 
into the space to be heated by an indoor blower to serve as a heating heat 
source. The refrigerant is absorbed into the solution to provide a 
concentrated solution (a solution containing the refrigerant) which is 
returned to the generator by means of a solution pump in one cycle. While 
defrosting is being carried out, no refrigerant flows through the other 
indoor heat exchanger. However, the heat generated in the heating mode 
remains in the system and can be advantageously utilized as a heating heat 
source. 
Another novel feature of the invention is that the system provided by the 
invention is a heat pump and absorption type cooling and heating system 
with an air heat source which is suitable for using a refrigerant of high 
pressure. 
Still another feature is that defrosting of two evaporators can be 
simultaneously carried out in a defrosting mode. 
Still another feature is that in a heating mode, a refrigerant of high 
temperature is allowed to pass through one of the two indoor heat 
exchangers and a solution of high temperature are allowed to flow through 
the other indoor heat exchanger while performing absorption, so that the 
heat of the refrigerant of high temperature and the heat of absorption can 
both be utilized as heating heat sources. 
A further feature is that in a heating mode, the outdoor heat exchanger and 
the absorber are both made to function as evaporators to increase the heat 
transfer area of the evaporator, to thereby increase evaporating 
capabilities. This is conductive to the improved coefficient of 
performance, and enables water to be used readily as a heat exchange fluid 
besides air. 
the invention offers the aforesaid many advantages. Thus the system 
provided by the invention can function as a heat pump and absorption type 
cooling and heating system with an air heat source which is high in 
performance and capable of contributing to energy conservation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a refrigeration cycle in a systematic view in which a 
refrigerant flows through two indoor heat exchangers in a series in a 
cooling mode. More specifically, a refrigerant gas section of a generator 
1 is connected in series with a first indoor heat exchanger 7, a second 
valve 8 which is an on-off valve, and a second indoor heat exchanger 9 
through a first change-over valve 2 which is a four-way valve, an outdoor 
heat exchanger 3, a second change-over valve 4 which is a four-way valve, 
a first valve 6 which is a check valve, and a first expansion valve 5 
which is pressure reducing means, via lines 10, 11, 12, 13, 14, 15, 16, 17 
and 18, so that the first and second indoor heat exchangers 7 and 9 are 
connected in series with each other and the exchanger 9 is connected via a 
line 20 to point of confluence 19 with a diluted solution. 
A solution section of the generator 1 is connected through a pressure 
reducing valve 21 to the point of confluence 19 via lines 22 and 23. The 
point of confluence 19 is connected to an absorber 25 through a third 
valve 24 which is a check valve via lines 26 and 27. The absorber 25 is 
connected to the second change-over valve which is a four-way valve to the 
generator 1 through a solution pump 28 via lines 29, 30 and 31. The first 
change-over valve 2 which is a four-way valve is connected through the 
first indoor heat exchanger 7 to a second expansion valve 32 which is 
pressure reducing means via lines 33, 16, 15 and 34. The second expansion 
valve is connected to the outdoor heat exchanger 3 through the first 
change-over valve 2 which is a four-way valve via lines 35 and 11. The 
outer heat exchanger 3 is connected through the second chage-over valve 4 
which is a four-way valve, the absorber 25 and a fifth valve 36 which is 
an on-off valve to the point of confluence 19 via lines 12, 19, 27, 37 and 
38. The point of confluence 19 is connected is connected to the second 
change-over valve 4 which is a four-way valve through the second indoor 
heat exchanger 9, and an eight valve 39 which is a check valve via lines 
20, 18, 40 and 41. A third expansion valve 42 which is pressure reducing 
means is connected in parallel with the third valve 24 which is a check 
valve and the fifth valve 36 which is an on-off valve via lines 43 and 44. 
FIG. 2 shows one example of the operation circuit for the absorption type 
cooling and heating system of the construction shown in FIG. 1. 45 is an 
operation switch having an operation contact 46 and a shutdown contact 47, 
the former being connected to an operation mode change-over switch 48. 49 
is a cooling operation contact, and 50 a heating operation contact. The 
cooling operation contact 49 is connected to an auxiliary relay 51, and 
the heating operation contact 50 is connected to a timer 53 and a 
thermostat contact 54 of a defrosting operation switch 52. A contact 55 is 
a heating contact and a contact 56 is a defrosting contact. The contact 55 
is connected to an auxiliary relay 57 and the contact 56 is connected to 
an auxiliary relay 58. The number of defrosting operations and the 
defrosting time are set by means of the timer 53 and thermostat 59. 
60 is an electromagnetic contact of the solution pump 28 connected in 
series with positive contacts 51a, 57a and 58a of the auxiliary relays 51, 
57 and 58 respectively. 61 is an electromagnetic contact of a blower 62 
for the outdoor heat exchanger connected in parallel with the 
electromagnetic contact 60 of the solution pump 28 through a reverse 
contact 58b of the auxiliary relay 58. 63 is an electromagnetic contact of 
a blower 64 for the indoor heat exchangers connected in parallel with the 
blower circuit for the outdoor heat exchanger. 65 is an auxiliary realy. 
66 is an electromagnetic coil of the second change-over valve 4 which is a 
four-way valve connected in series with another positive contact 51a of 
the auxiliary relay 51. 67 is an electromagnetic coil of the second valve 
8 which is an on-off valve connected in parallel with the electromagnetic 
coil 66 of the second change-over valve 4 which is a four-way valve. 68 is 
an electromagnetic coil of the first change-over valve 2 which is a 
four-way valve connected in series with other positive contacts 51a and 
58a of the auxiliary relays 51 and 58. 69 is an electromagnetic coil of 
the fifth valve 36 which is an on-off valve connected in series with a 
reverse contact 51b of the auxiliary relay 51 and another positive contact 
57a of the auxiliary relay 57. 
Operation of the embodiment of the absorption type cooling and heating 
system in conformity with the invention as shown in FIGS. 1 and 2 will now 
be described. 
In performing a cooling operation, the operation switch 45 is changed over 
to the operation contact 46 and an operation mode change-over switch 48 is 
set at the cooling operation contact 49. This energizes the auxiliary 
relay 51, and the electromagnetic contact 61 of the blower 62 for the 
outdoor heat exchanger and the electromagnetic contact 63 of the blower 64 
for the indoor heat exchangers are energized through the electromagnetic 
contact 60 of the solution pump 28 connected to the positive contact 51a 
of the auxiliary relay 51 and the reverse contact 58b of the auxiliary 
relay 58 which is not energized, so that the solution pump 28, blower 62 
for the outdoor heat exchanger and the blower 64 for the indoor heat 
exchangers start operation. The auxiliary relay 65 is a circuit for 
controlling the heating source of the generator 1 and fired in conjunction 
with a combustion gas control circuit, for example. Energization of the 
auxiliary relay 51 also energizes the electromagnetic coil 68 of the first 
change-over valve 2 which is a four-way valve and the electromagnetic coil 
66 of the second change-over valve 4 which is a four-way valve through 
another positive contact 51a of the auxiliary relay 51, so that the first 
and second change-over valves 2 and 4 are switched and have their passages 
oriented in directions indicated in solid lines in FIG. 1. The 
electromagnetic coil 67 is energized as soon as the second change-over 
valve 4 is switched, so that the second valve 8 which is an on-off valve 
is opened. Meanwhile the fifth valve 36 which is also an on-off valve is 
closed because no current is passed to the electromagnetic coil 69. 
The generator 1 has a mixture of a refrigerant, such as Fron 22 
(CHCLF.sub.3), and an absorbing agent, such as tetraethyleneglycol 
dimethylether, contained therein and heated as by combustion gas. Besides 
the combustion gas, waste heat or solar heat may be used as a heat source. 
Refrigerant gas of high temperature and high pressure is produced in the 
generator 1 by being separated from the absorber which is a solution as 
the generator 1 is heated and flows through line 10, a solid line passage 
in the first change-over valve 2 which is a four-way valve and line 11 
into the outdoor heat exchanger 3. In the outdoor heat exchanger 3 
functioning as a condenser, the refrigerant gas undergoes heat exchange 
with outdoor air forcedly introduced thereinto by the blower 62, to be 
cooled by dissipating heat and changed into a liquid state. The liquid 
refrigerant of high pressure flows through line 12, a solid line passage 
in the second change-over valve 4 which is a four-way valve, line 13 and 
the first valve 6 which is a check valve into the first expansion valve 5 
which is pressure reducing means. When the liquid refrigerant flows from 
the second change-over valve 4 to line 13, some of it flows in the 
direction of line 41. However, since the eighth valve 39 which is a check 
valve preventing inflow from line 41 to line 40 is mounted in line 41, the 
liquid refrigerant merely fills the line 41. The refrigerant gas of low 
temperature and low pressure produced at the first expansion valve 5 by 
pressure reduction upon expansion flows through lines 14 and 15 into the 
first indoor heat exchanger 7 where air is forcedly supplied by the blower 
64, so that the refrigerant gas exchanges heat with the indoor air to 
enable the first indoor heat exchanger 7 to function as an evaporator to 
cool the air in the space. Meanwhile the refrigerant of low temperature 
and low pressure also enters line 34. However, since the second expansion 
valve 32 which is pressure reducing means is maintained in communication 
with the outlet side of the first indoor heat exchanger 7 through line 35, 
first change-over valve 2, line 33 and line 16, there is no pressure 
differential between the front and rear of the second expansion valve 32 
and no refrigerant gas of low pressure and low temperature is allowed to 
flow therethrough. The refrigerant gas released from the first indoor heat 
exchanger 7 flows through lines 16 and 17, second valve 8 which is an 
on-off valve and line 18 into the second indoor heat exchanger 9 where 
heat exchange takes place by evaporation between the refrigerant gas and 
the indoor air forcedly circulated by the blower 64, to cool the indoor 
air and cool the space. The refrigerant gas flowing through the second 
valve 8 finds its way into line 40 too. However, since the liquid 
refrigerant of high pressure fills line 41 connected to line 40 via the 
eighth valve 39 39 which is a check valve, the eighth valve 39 is kept 
from being opened by the refrigerant gas of low pressure in line 40 and 
merely a portion of the low pressure refrigerant gas stays in line 40. The 
refrigerant gas that has performed an evaporation action in the two or 
first and second indoor heat exchangers 7 and 9 and cooled the indoor air 
flows through line 20 and reaches the point of confluence 19 with a 
diluted solution. 
Meanwhile a diluted solution of low refrigerant concentration from which 
the refrigerant gas has been separated in the generator 1 flows through 
line 22 to the pressure reducing valve 21 where it has its pressure 
reduced and flows through line 23 toward the point of confluence 19 from 
which it flows through line 26, third valve 24 which is a check valve and 
line 27 into the absorber while being mixed with the refrigerant gas. At 
the absorber 25, the refrigerant and diluted solution mix with each other 
while being cooled by the outdoor air supplied by the blower 62, so that 
the refrigerant is absorbed by the diluted solution which is an absorbing 
agent and the diluted solution changes into a concentrated solution 
containing the refrigerant. At the absorber 25, heat of absorption is 
generated and dissipated. The concentrated solution is passed from the 
absorber 25 by the solution pump 28 through line 29 and second change-over 
valve 4 whch is a four-way valve and line 30, to be drawn by suction into 
the solution pump 28 where it has its pressure raised and transferred to 
the generator 1. At the generator 1, the concentrated solution generates 
refrigerant gas again so as to allow the aforesaid series of operations to 
be repeated to carry out space cooling. 
In performing a heating operation, the operation mode change-over switch 48 
is changed over to the heating operation contact 50 having connected 
thereto the defrosting operation switch 52 for performing a defrosting 
operation which has its thermostat 59 selectively connected to the heating 
contact 55 or defrosting contact 56 by the timer 53 and sensor. When the 
thermostat 59 is connected to the heating contact 55, the auxiliary relay 
57 is energized and its positive contact 57a closes, and the 
electromagnetic contact 61 of the outdoor heat exchanger blower 62 and the 
electromagnetic contact 63 of the indoor heat exchanger blower 64 are 
energized through the electromagnetic contact 50 of the solution pump 28 
and the reverse contact 58b of the auxiliary relay 58 that is not 
energized, so that the solution pump 28, outdoor heat exchanger blower 62 
and indoor heat exchanger blower 64 start operating. Energization of the 
auxiliary relay 65 controls the heating source of the generator 1 as is 
the case with the cooling operation. The auxiliary relays 51 and 58 not 
being energized, the contacts 51a and 58a remain open and the 
electromagnetic coils 68 and 66 of the first change-over valve 2 and 
second change-over valve 4 which are four-way valves are no energized. 
Thus the passages of the first and second change-over valves 2 and 4 are 
connected to lines through broken line passages. The electromagnetic oil 
67 of the second valve 8 which is an on-off valve is not opened either, so 
that the second valve 8 remains closed. The electromagnetic coil 69 of the 
fifth valve 36 which is an on-off valve is energized and the valve is 
opened because the reverse contact 51b is closed. 
Thus the refrigerant gas of high temperature and high pressure produced in 
the generator 1 flows through line 10, a broken line passage of first 
change-over switch 2 and lines 33 and 16 into the first indoor heat 
exchanger 7 which functions as a condenser and causes heat to be released 
by heat exchange taking place between the refrigerant gas and the indoor 
air forcedly blown by the blower 64, to heat the space in a heating 
operation. The refrigerant gas flows into the first indoor heat exchanger 
2 through line 16 but it also flows into line 17. However, since the 
second valve 8 which is an on-off valve is closed, the refrigerant does 
not flow. The liquid refrigerant of high pressure produced by condensation 
at the first indoor heat exchanger 7 flows through lines 15 and 34 and has 
its pressure reduced by the second expansion valve 32 which is pressure 
reducing means into a refrigerant gas of low pressure and low temperature 
which flows through line 35, a broken line passage of first change-over 
valve 2 which is a four-way valve and line 11 into the outdoor heat 
exchanger 3. The outdoor heat exchanger 3 functions as an evaporator, so 
that heat exchange takes place between the refrigerant gas and the outdoor 
air forcedly blown by the blower 62 and the gas absorbs heat. Meanwhile 
the first valve 6 which is a check valve keeps the refrigerant from 
flowing into line 14. The refrigerant released from the outdoor heat 
exchanger 3 flows through line 12, a broken line passage of second 
change-over valve 4 which is a four-way valve and line 29 into the 
absorber 25 which performs an absorbing action in a cooling mode but 
functions, in a heating mode, as an evaporator allowing the refrigerant 
alone to flow thereinto to exchange heat with the outdoor air. The 
refrigerant gas released from the absorber 25 flows through lines 27 and 
37, fifth valve 36 which is an on-off valve and line 38 to the point of 
confluence 19 with a diluted solution. The refrigerant gas in line 27 
flows into line 44 too, but does not flow therethrough because there is no 
pressure differential at the front and rear of the third expansion valve 
42 which is pressure reducing means. The third valve 24 which is a check 
valve functions to prevent flow from line 27. 
On the other hand, the diluted solution separated from the refrigerant gas 
in the generator 1 flows through the pressure reducing valve 21 by 
pressure differential toward the point of confluence 19 and mixed with the 
refrigerant gas referred to hereinabove, as is the case with the cooling 
operation. The mixture of diluted solution and refrigerant gas flows 
through line 20 into the second indoor heat exchanger 9 which functions as 
an absorber to perform an absorbing action. The heat of absorption 
generated is released into the indoor air blown forcedly by the blower 64 
to heat the space. In this way, one of the two indoor heat exchanger 
functions as a condenser and the other indoor heat exchanger functions as 
an absorber and the heat of condensation and the heat of absorption are 
both used as heating heat sources. The outdoor heat exchanger 3 and 
absorber 25 function as evaporators to increase the heat transfer area of 
the evaporator, thereby improving the coefficient of performance. The 
concentrated solution released from the second indoor heat exchanger 9 is 
caused by the solution pump 28 to flow through lines 18 and 40, eight 
valve 39 which is a check valve, second change-over valve 4 and line 30 
into the solution pump 28 which raises the pressure of the solution and 
returns same to the generator 1 where refrigerant gas is generated again, 
so that the aforesaid operations can be carried out continuously to effect 
space heating. The concentrated solution that has performed absorption 
flows through the eighth valve 39 that is a check valve and line 41 into 
line 13. However, since the first valve 6 which is a check valve blocks 
the passage of solution by high pressure gas, to keep the concentrated 
solution from flowing to the high pressure refrigerant gas side. 
Continuation of heating operation will cause frost formation to take place 
on the heat exchange surfaces of the outdoor heat exchanger 3 functioning 
as an evaporator and the absorber 25, thereby interfering with 
evaporation. This makes it necessary to perform defrosting at a suitable 
time. A command for performing defrosting is given by the temperature 
sensor while the timer 53 of the defrosting operation switch 52 is being 
actuated, to bring the thermostat 59 into engagement with the defrosting 
contact 56. This deenergizes the auxiliary relay 57 and energizes the 
auxiliary relay 58, to open the positive contact 57a and close the 
positive contact 58a. This permits the solution pump 28 and indoor heat 
exchanger blower 64 to continue operation. However, with the reverse 
contact 58b being open, the outdoor heat exchanger blower 62 is rendered 
inoperative. Also the electromagnetic coil 68 is energized and the first 
change-over valve 2 which is a four-way valve has its passages switched 
because the positive contact 58a is closed, so that the passage of the 
refrigerant is switches to a solid line passage as is the case with the 
cooling operation. The second change-over valve 4 allows the refrigerant 
to flow through the same passage as in the heating mode. The 
electromagnetic coil 69 of the fifth valve 36 is de-energized to close the 
valve 36, because the positive contact 57a is open. The second valve 8 is 
closed as is the case witht the heating mode. This allows the refrigerant 
gas of high temperature and high pressure to flow through line 10, first 
change-over valve 2 which is a four-way valve and line 11 into the outdoor 
heat exchanger 3. With the blower 62 being inoperative, the frost on the 
surface of the outdoor heat exchanger 3 is separated from the surface 
efficiently by the high temperature refrigerant flowing through the heat 
exchanger 3. The high temperature refrigerant gas flows through line 12, 
second change-over valve 4 which is a four-way valve and line 29 into the 
absorber 25 functioning as an evaporator to melt the frost on the surface, 
to thereby effect defrosting. In this case, the blower 62 of the absorber 
25 is rendered inoperative. 
Defrosting of the outdoor heat exchanger 3 and absorber 25 functioning as 
evaporators is simultaneously carried out by the high temperature 
refrigerant gas. Upon completion of the defrosting, the refrigerant gas is 
condensed into a liquid refrigerant which, after having its pressure 
reduced by the third expansion valve 42 which is pressure reducing means, 
flow through lines 43 and 26 to the point of confluence 19 while not being 
evaporated yet. The diluted solution separated at the generator 1 which is 
at high temperature flows through line 20 while being mixed with the 
refrigerant not evaporated yet, and the mixture has its temperature raised 
by the heat of mixing and flows into the second indoor heat exchanger 9, 
to perform absorption while releasing heat into the indoor air forcedly 
blown by the blower 64. Space heating can be effected by the heat released 
into the indoor air, so that it is possible to carry out heating by the 
second indoor heat exchanger 9 while carrying out defrosting by the 
outdoor heat exchanger 3 and absorber 25 functioning as evaporators. 
Meanwhile no refrigerant flows to the first indoor heat exchanger 7 but 
the high temperature and high pressure refrigerant for heating operation 
remains therein, and its heat is released into the indoor air by operation 
of the blower 64 to be utilized as a heating heat source. 
The concentrated solution that has performed absorption at the second heat 
exchanger 9 flows through line 40, eight valve 39 which is a check valve, 
lines 41 and 13, a broken line passage of second change-over valve 4 which 
is a four-way valve and line 30 to be drawn by suction into the solution 
pump 28, to have its pressure raised thereby and returned to the generator 
1. The concentrated solution returned to the generator 1 generates 
refrigerant gas again, so that the aforesaid series of operation are 
carried out continuously to effect defrosting of the evaporators while 
performing space heating. A portion of the concentrated solution flowing 
through eighth valve 39 which is a check valve and lines 41 and 13 toward 
the second change-over valve 4 which is a four-way valve flows toward the 
first expansion valve 5 connected to line 13. However, since the first 
indoor heat exchanger 7 side is full of high temperature and high pressure 
refrigerant gas, the concentrated solution is kept from flowing through 
the first valve 6 that is a check valve. 
After the system has been switched to a defrosting mode as aforesaid, the 
second indoor heat exchanger 9 is allowed to function as an absorber while 
keeping the indoor blowers functioning in the same manner as in the 
heating mode. By this feature, the heat of absorption can be utilized as a 
heating heat source and at the same time the heat of the high temperature 
refrigerant in the closed piping circuit including the first indoor heat 
exchanger 7 can be effectively utilized as a heating heat source. 
FIG. 3 shows another embodiment of improved constructional form in which 
the concentrated solution returned to the generator is further heated 
before being utilized again, to thereby increase operation efficiency. In 
the figure, parts having substantially the same functions as the parts 
shown in the basic cycle diagram shown in FIG. 1 will be designated by 
like reference characters and their description will be omitted. 
A three-way change-over valve 100 is mounted in line 22 through which a 
diluted solution flows from the generator 1 to the pressure reducing valve 
21, and a line 101 connects the three-way change-over valve 100 to a point 
in line 22 anterior to valve 21. A heat exchanger 102 is mounted between 
the lines 21 and 31 to allow the diluted solution and concentrated 
solution flowing through the line 22 and line 31 through which the 
concentrated solution flows respectively to exchange heat with each other. 
By this structural arrangement, the heat of the high temperature diluted 
solution can be given to the concentrated solution to raise the 
temperature of the concentrated solution, thereby enabling economizing to 
be effected on the amount of heat used for heating in the generator 1. The 
provision of the three-way change-over valve 100 enables the direction of 
flow of the diluted solution to be suitably selected, to allow same to 
flow without being subjected to heat exchange with the concentrated 
solution. 
A heat exchanger 103 is intended to effectively utilize the heat generated 
as the refrigerant and diluted solution are mixed to heat the concentrated 
solution, to increase efficiency in a cooling mode. The heat exchanger 103 
is located between line 31 through which the concentrated solution flows 
and line 104 connecting the point of confluence 109 of the diluted 
solution and refrigerant to the second valve 24 which is a check valve, to 
enable heat exchange to take place between the concentrated and diluted 
solutions. 
By the aforesaid structural arrangement, the concentrated solution returned 
to the generator 1 has its temperature increased still higher, so that the 
heat required to carry out heating at the generator 1 can be saved and the 
object of energy conservation can be accomplished. 
FIG. 4 shows still another embodiment, in which some alterations are made 
in the circuit shown in FIG 1. One of the distinctions is that the two 
indoor heat exchangers 7 and 9 are connected in parallel with each other 
in a cooling mode. Another distinction is that the first change-over valve 
is a three-way valve 105 connected at its inlet end to line 10 and at its 
one outlet end to line 11 and at its another outlet end to line 15 through 
a line 106. Connected to line 15 is a line 107 that has connected in 
series therewith a first valve 108 which is an on-off valve, a line 109, 
first expansion valve 5 which is pressure reducing means and a line 110, 
before being connected to the second change-over valve 4 which is a 
four-way valve. The eighth valve 39 which is a check valve is connected in 
parallel with the first expansion valve 5. The second indoor heat 
exchanger 9 is connected to line 109 via a line 111 and to line 20 via a 
line 112. Line 11 has a line 113 connected thereto at one end and the 
other end of line 113 is connected in series with a fourth valve 114 which 
is an on-off valve and the second expansion valve 32 which is pressure 
reducing means, before being connected to the second valve 8 which is an 
on-of valve through line 16. 
With the embodiment shown in FIG. 4 being constructed as aforesaid, the 
fourth valve 114 which is an on-off valve is closed in a cooling mode to 
allow a refrigerant gas to flow through line 10, a solid line passage of 
first change-over 105 which is a three-way valve and line 11 into the 
outdoor heat exchanger 3. The liquid refrigerant produced by condensation 
at the outdoor heat exchanger 3 is divided into two streams: one stream 
flows through line 12, a solid line passage of second change-over valve 4 
which is a four-way valve, line 110, first expansion valve 5 which is 
pressure reducing means, line 109 and line 111 into the second indoor heat 
exchanger 9, and the other stream flows through first valve 108 which is 
an on-off valve and lines 107 and 15 into the first indoor heat exchanger 
7. Thus two streams of low temperature and low pressure refrigerant having 
the pressure reduced flow in parallel into the two indoor heat exchangers 
9 and 7 to perform evaporation. The refrigerant from the first indoor heat 
exchanger 7 flows through lines 16 and 115, second valve 8 which is an 
on-off valve and line 20 and joins the refrigerant from the second indoor 
heat exchanger 9 flowing through lines 112 and 20, to flow toward the 
point of confluence 19 with a diluted solution. The refrigerant released 
from the first valve 108 which is an on-off valve flows into line 106 too. 
However, since the broken line passage of the first change-over valve 105 
which is a three-way valve is blocked, the refrigerant is not allowed to 
flow therethrough. The refrigerant flowing from the first indoor heat 
exchanger 7 into line 16 flows into line 103 too. However, the refrigerant 
is kept from flowing therethrough by the fourth valve 114 which is closed. 
The diluted solution flows through lines 22 and 23 to the point of 
confluence 19. While flowing therethrough, the diluted solution heats the 
concentrated solution through the heat exchanger 102. The mixture flowing 
from line 20 to the point of confluence 19 flows through line 104, third 
valve 24 which is a check valve and line 27 into the absorber 25 to effect 
absorption. With the fifth valve 36 which is an on-off valve being closed, 
no refrigerant flows through lines 38 and 37. Since no pressure 
differential is produced at the front and rear of the third expansion 
valve 42 which is pressure reducing means, no refrigerant flows to lines 
43 and 44. Thus all the refrigerant flows through line 104 and the heat of 
the mixture solution flowing through line 104 is utilized for heating 
through the heat exchanger 103 the concentrated solution that has 
completed its absorbing operation. The concentrated solution released from 
the absorber 25 flows through line 29, second change-over velve 4 which 4 
is a four-way valve and line 30 to the solution pump 28 which raises the 
pressure of the concentrated solution which is then heated by the heat 
exchangers 102 and 103, before being returned to the generator 1. 
In a heating mode, refrigerant gas flows through line 10, first change-over 
valve 105 which is a three-way valve and lines 106 and 15 into the first 
indoor heat exchanger 7 functioning as a condenser, to provide a heating 
heat source. The refrigerant gas is then passed through lines 16 and 113 
into the second expansion valve 32 which is pressure reducing means, to 
have its pressure reduced by expansion into a liquid refrigerant. The 
liquid refrigerant flows through fourth valve 114 which is an on-off valve 
and lines 13 and 111 into the outdoor heat exchanger 3 functioning as an 
evaporator, so that evaporation is carried out. The refrigerant flows into 
line 115 but kept from flowing therethrough because the second valve 8 
which is an on-off valve is closed. The liquid refrigerant produced by 
condensation flows through line 12, second change-over valve 4 which is a 
four-way valve, line 29, absorber 25 functioning as an evaporator, lines 
27 and 37, fifth valve 36 which is an on-off valve and lines 38 and 26 to 
the point of confluence 19 at which the liquid refrigerant mixes with a 
diluted solution flowing through lines 22 and 23 which is a diluted 
solution passage. Then the mixture solution flows through lines 20 and 112 
into the second indoor heat exchanger 9 functioning as an evaporator, so 
that the heat of absorption can be utilized as a heating heat source. The 
concentrated silution that has completed absorption flows through line 
111, eighth valve 39 which is a check valve, line 110, second changeover 
valve 4 which is a four-way valve and line 30, to be drawn by suction into 
the solution pump 28. At the solution pump 28, the solution has its 
pressure raised, and is heated through heat exchange by the heat exchanger 
102 while flowing through line 31, before reaching the generator 1. In 
this way, the heat of the high temperature refrigerant and the heat of 
absorption obtained by absorption both can be utilized as heating heat 
sources. 
In a defrosting mode, refrigerant gas flows through line 10, a solid line 
passage of first change-over valve 105 which is a three-way valve and line 
11 into the outdoor heat exchanger 3, to carry out defrosting of the 
outdoor heat exchanger 3 functioning as an evaporator in the heating mode. 
With the fourth valve 114 which is an on-off valve being closed, no 
refrigerant flows to a path connected to line 113. Then the refrigerant 
flows from the outdoor heat exchanger 3 through line 12, second 
change-over velve 4 which is a four-way valve and line 29 into the 
absorber 25 functioning as an evaporator to effect defrosting. Then the 
refrigerant flows through lines 27 and 44, third expansion valve 42 which 
is pressure reducing means where it has its pressure reduced, and lines 43 
and 26 to the point of confluence 19 with a diluted solution. At the point 
of confluence 19, it mixes with a high temperature diluted solution 
flowing through lines 22 and 23 and the mixture flows through lines 20 and 
112 into the second indoor heat exchanger 9 functioning as an absorber, 
where it releases the heat of absorption which serves as a heating heat 
source to carry out space heating. 
Thus it will be appreciated that defrosting can be carried out while 
heating is being carried out, so that the system does not lose its heating 
capabilities even while defrosting is being carried out. 
FIG. 5 shows a further embodiment which is fundamentally distinct from the 
embodiments shown in FIGS. 1 and 4 in that the outdoor heat exchanger 
functioning as an evaporator in a heating mode is connected in parallel 
with the absorber in a circuit. 
In a cooling mode, refrigerant gas flows through line 10, a solid line 
passage of first change-over valve 2 which is a four-way valve and line 11 
into the outdoor heat exchanger 3 functioning as a condenser where it is 
changed into a liquid state by condensation. The liquid refrigerant flows 
through line 12, a second change-over valve 200 which is a three-way 
valve, first expansion valve 5 functioning as pressure reducing means 
where it has its pressure reduced by expansion, and lines 201 and 111 into 
the second indoor heat exchanger 9 functioning as an evaporator. Also it 
flows through a line 202, first valve 6 which is a check valve and lines 
203 and 15 into the first indoor heat exchanger 7 functioning as an 
evaporator, so as to cool the indoor air and effect space cooling. The 
refrigerant further flows through lines 112 and 20, lines 16 and 17, 
second valve 8 which is an on-off valve and line 18, so that the 
refrigerant released from the indoor heat exchangers 7 and 9 flows through 
line 20 to the point of confluence 19 with a diluted solution. At the 
point of confluence 19, the refrigerant mixes with a diluted solution 
flowing from the generator 1 through lines 22 and 23, and the mixture 
flows through lines 204 and 205, third valve 24 which is a check valve and 
a line 206 into the absorber 25, to carry out absorption. Upon completion 
of the absorption, the concentrated solution further flows through lines 
207 and 208, a third change-over valve 209 which is a three-way valve and 
a line 210, to be drawn by suction into the solution pump 28 to have its 
pressure raised thereby. The pressurized solution is returned through line 
31 to the generator 1. To form the cooling circuit described hereinabove, 
a seventh valve 211 and a sixth valve 212 which are on-off valves are 
closed and the second valve 8 which is also an on-off valve is opened, as 
they are controlled to attain the end. 
In a heating mode, refrigerant gas flows through line 10, a broken line 
passage of first change-over valve 2 which is a four-way valve and lines 
33 and 16 into the first indoor heat exchanger 7 functioning as a 
condenser, to heat the indoor air and effect space heating. The liquid 
refrigerant produced by condensation flows through lines 15 and 34, second 
expansion valve 32 which is pressure reducing means where it has its 
pressure reduced to be changed into a refrigerant gas of low temperature 
and low pressure, line 35, and a broken line passage of first change-over 
valve 2 which is a four-way valve into lines 11 and 213. The refrigerant 
flowing into line 11 flows through the outdoor heat exchanger 3 
functioning as an evaporator, line 12, second change-over valve 200 which 
is a three-way valve, lines 24 and 215, sixth valve 212 which is an on-off 
valve and lines 216 and 204, to the point of confluence 19 with a diluted 
solution. Meanwhile the refrigerant flowing into line 213 flows through 
seventh valve 211 which is an on-off valve and lines 217 and 207 into the 
absorber 25 functioning as an evaporator, to perform evaporation. From the 
absorber 25, the refrigerant flows through lines 206, 218 and 215, sixth 
valve 212 which is an on-off valve and lines 216 and 204 to the point of 
confluence 19. The refrigerant flowing in parallel through the outdoor 
heat exchanger 3 and absorber 25 functioning as evaporators in this way 
mixes at the point of confluence 19 with a diluted solution flowing from 
the generator 1 through lines 22 and 23, and the mixture flows through 
lines 20 and 112 into the second indoor heat exchanger 9 functioning as an 
absorber. Thus the heat of absorption generated by the absorbing operation 
is released into the indoor air to serve as a heating heat source. 
According to the invention, the heat of the refrigerant of high 
temperature and the heat of absorption can both be utilized as heating 
heat sources in a heating mode. Upon completion of absorption, the 
concentrated solution flows through lines 111 and 219, third change-over 
valve 209 which is a three-way valve and line 210, to be drawn by suction 
into the solution pump 28 to have its pressure raised. The pressurized 
solution is returned through line 31 to the generator 1. To form the 
aforesaid heating circuit, the second valve 8 which us an on-off valve is 
closed and the seventh and sixth valves 217 and 216 which are also on-off 
valves are opened, as they are controlled to attain the end. 
In a defrosting mode, a refrigerant gas of high temperature flows through 
line 10, first change-over valve 2 which is a four-way valve and lines 11 
and 213, to flow thereafter in two streams in parallel. The refrigerant 
flowing into line 11 flows through the outdoor heat exchanger 3 
functioning as an evaporator in a heating mode to carry out defrosting 
therein. Thereafter the refrigerant flows through line 12, second 
change-over valve 200 which is a three-way valve, lines 214, 218 and 220, 
a third expansion valve 42 which is pressure reducing means where it has 
its pressure reduced by expansion and lines 221 and 204 to the point of 
confluence 19 with a diluted solution. The refrigerant flowing into line 
213 flows through seventh valve 211 and lines 217 and 207 into the 
absorber 25 functioning as an evaporator in a heating mode, to carry out 
defrosting therein. Thereafter the refrigerant flows through lines 206, 
123 and 220, third expansion valve 42 which is pressure reducing means and 
lines 221 and 204 to the point of confluence 19. 
At the point of confluence 19, the refrigerant mixes with a diluted 
solution of high temperature from the generator 1 through lines 22 and 23, 
and the mixture flows through lines 20 and 112 into the second indoor heat 
exchanger 9 functioning as an absorber, to perform absorption, so that the 
heat of absorption is released into the indoor heat to heat same to 
perform a heating operation by the heat of absorption. The first indoor 
heat exchanger 7 constitutes a closed circuit filled with a refrigerant of 
high temperature and high pressure, and the heat generated in the heating 
mode is utilized as a heating heat source in the defrosting mode. 
To form the aforesaid defrosting circuit, the sixth valve 212 and second 
valve 8 which are on-off valves are closed and the seventh valve 211 which 
is also an on-off valve is opened, as they are controlled to attain the 
end. 
Although not shown in FIG. 5, the circuit shown therein may include a heat 
exchanger for utilizing the heat of mixing produced when a diluted 
solution of high temperature is mixed with refrigerant in a cooling mode 
to increase the temperature of the concentrated solution returned to the 
generator 1 to increase operation efficiency, as is the case with the 
circuits shown in FIGS. 3 and 4.