Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
SPECIFICATION
AI7~ REFRIGERANT ICE FORMING EQUIPMENT
Field of Application in Industry
The invention relates to an air refrigerant ice forming
equipment in which air is utilized as a working medium. More
particularly, it relates to an air refrigerant ice forming
equipment suitable for use in facilities for playing ice sports
including bobsl.eigh, ice skate, ice hockey and other ice
sports.
Prior Art
In facilities for playing ice sports including bobsleigh,
ice skate, ice hockey and other ice sports, it is necessary to
properly and quickly form ar supplement ice.
In such facilities for playing ice sports use has hereto-
fore been made of ice forming equipment in which a working
2 0 medium such as fron or ammonia of a refrigeration cycle is
evaporated in ice' forming coils (evaporators) buried in an ice
rink or course of the facilities. Also use has been made of
ice forming equipment in which brine made in a refrigerator is
circulated through the above-mentioned ice forming coils.
1
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However, with the ice forming equipment mentioned above,
leakage of the working medium and/or brine may occur as a re-
sult of mal-construction or changes with year of the equipment.
Particularly, when strainers are cleaned or replaced at the
S time of periodical maintenance of the equipment, the leakage of
the working medium and/or brine necessarily occurs. It is re-
ported that an amount of the working medium released in one
year has been calculated as amounting to 5 ~ of the working
medium charged in the equipment
Leakage of fron poses a problem of destruction of the
ozone layers, while leakage of ammonia causes air and soil pol-
lution and leakage of brine causes soil pollution.
Accordingly, from the view point of protecting environment, it
1S is of urgent necessity to take a measure for avoidance of the
above-mentioned problems.
Also known in the art is a refrigeration cycle in which
air is used as a working medium. However, since the efficiency
2 0 of the air refrigerant refrigeration cycle is generally low, a
large driving force or electric power is consumed.
Accordingly, running of the air refrigerant refrigeration cycle
is rather expensive and less energy saving, and therefore, has
not been generally practiced in an ice forming equipment. For
2S example, in a case of forming ice in ambient atmosphere at a
2
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temperature of 5 °C., an air refrigerant refrigerator in which
air is used as a working medium exhibits a coefficient of per
formance of about 0.8, which value is about 1/3 to 1/2 of the
coefficient of performance of a refrigerator in which fron is
used as a working medium.
On the other hand, a cogeneration system for comprehen-
sively utilizing heat and power of a heat engine has come into
wide use, and on a refrigerator wherein power of a heat engine
of a cogenerati~~n system is utilized as a source for driving
the refrigerator- various technologies have been developed how
to achieve the most energy saving result. All refrigerators
concerned, however, have been those using fron or ammonia as a
working medium.
Object of the Invention
An object of the invention is to effectively form ice in
facilities for p:Laying ice sports without using fron or ammonia
as a working mE:dium and without using brine as a cooling
2 0 medium.
Disclosure of they Invention
According t~~ the invention there is provided an air re
frigerant ice forming equipment having formed therein a refrig
2 5 eration cycle using air as a working medium, said refrigeration
3
cycle comprising a passage for air circulation incorporating an
air compresso~_, a compressed air cooler for cooling the air
compressed by the compressor with heat transfer media outside
the refrigeration cycle, an air expander for expanding the air
which has passed through the cooler to provide cold air and a
heat exchanger for ice formation using the cold air which has
passed the air expander disposed in the indicated order along
the flow of air, said passage for air cir la ; nr, ; n~1 "~; "~ a
return passag:g for returning the air whi ha passed throucxh
said heat Pxchanaer for i forma- »n o ash air compressor
characterized i.n
that said equipment further comprises a heat exchanger for
heat recovery wherein the air before entering the air expander
is heat exchanged with the air which has passed through the
heat exchanger for ice formation before the latter air is re-
turned to the air compressor.
The air refrigerant ice forming equipment according to the
invention may have one or more of the following features:
2 0 that said air expander has a rotor caused to rotate by the
action of air flowing through said passage for air circulation,
a rotating shaft of said rotor is coupled via a one-way clutch
to a rotating shaft of a power means for driving said air com-
pressor and
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that the air circulated through the passage for air
circulation is c:~ry sub~;tantially free from moistlzre anc~
said equipment is further provided with an exit port for
discharging apart of the dry and cold air c_>utsic~e the
equipment after the dry and cold air has passed through
said air expander either on its way to said heat
exchanger for ice formation or while it i~~ passing
through said heat exchanger for ic.e formaticon anc~ witlu an
inlet port having an air dehumidifier in said return
passage for introducing dry air into said passage for air
circulation by inhaling atmospheric air.
According to another aspect of the invention, there
is provided a:z air refrigerant ice forming equipment
having formed therein a refrigeration cycle using air as
a working medium, said refrigeration cycle comprising a
passage for air circulation incorporating an air
compressor, a compressed air cooler for ccocoliny the air
compressed by the compressor with heat transfer media
2 0 outside the refrigeration cycle, an air expane~er for
expanding the air which has passed through the cooler to
provide cold air and a heat exchanger for ice formation
using the cola air which has passed the air expander
disposed in the indicated order along the flaw of air,
2 5 said passage ;=cor ai:r circulation including a return
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CA 02148107 2001-08-09
passage for returning the air which has passed through said
heat exchanger for ice formation to said air compressor
characterized in that said equipment further comprising a
heat exchanger for heat recovery wherein the air before
entering the air expander is heat exchanged with the air
which has passed through the heat exchanger for ice
formation before the latter air is returned to the air
compressor, and that said equipment is further provided with
an exit port for discharging a part of the cold air outside
the equipment after the cold air has passed through said air
expander either on its way to said heat exchanger for ice
formation or while it is passing through said heat exchanger
for ice formation and with an inlet port in said return
passage.
According to yet another aspect of the invention, there
is provided an air refrigerant ice forming equipment having
formed therein a refrigeration cycle using air as a working
medium, said refrigeration cycle comprising a passage for
air circulation incorporating an air compressor, a
compressed air cooler for cooling the air compressed by the
compressor with heat transfer media outside the
refrigeration cycle, an air expander for expanding the air
which has passed through the cooler to provide cold air and
a heat exchanger for ice formation using the cold air which
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CA 02148107 2001-08-09
has passed the air expander disposed in the indicated order
along the flow of air, said passage for air circulation
including a return passage for returning the air which has
passed through said heat exchanger for ice formation to said
air compressor characterized in that said equipment further
comprising a heat exchanger for heat recovery wherein the
air before entering the air expander is heat exchanged with
the air which has passed through the heat exchanger for ice
formation before the latter air is returned to the air
compressor, and that said equipment is further provided with
an exit port for discharging a part of the cold air outside
the equipment after the cold air has passed through said air
expander either on its way to said heat exchanger for ice
formation or while it is passing through said heat exchanger
for ice formation and with an inlet port in said return
passage.
According to a further aspect of the invention, there
is provided an air refrigerant ice forming equipment having
formed therein a refrigeration cycle using air as a working
medium, said refrigeration cycle comprising a passage for
air circulation incorporating an air compressor, a
compressed air cooler for cooling the air compressed by the
compressor with heat transfer media outside the
refrigeration cycle, an air expander for expanding the air
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CA 02148107 2001-08-09
which has passed through the cooler to provide cold air and
a heat exchanger for ice formation using the cold air which
has passed the air expander disposed in the indicated order
along the flow of air, said passage for air circulation
including a return passage for returning the air which has
passed through said heat exchanger for ice formation to said
air compressor characterized in that said equipment further
comprising a heat exchanger for heat recovery wherein the
air before entering the air expander is heat exchanged with
the air which has passed through the heat exchanger for ice
formation before the latter air is returned to the air
compressor, that said air expander has a rotor caused to
rotate by the action of air flowing through said passage for
air circulation, a rotating shaft of said rotor being
coupled via a one-way clutch to a rotating shaft of a power
means for driving said air compressor and that the air
circulated through the passage for air circulation is dry
substantially free from moisture and said equipment is
further provided with an exit port for discharging a part of
the dry and cold air outside the equipment after the dry and
cold air has passed through said air expander either on its
way to said heat exchanger for ice formation or while it is
passing through said heat exchanger for ice formation and
with an inlet port having an air dehumidifier in said return
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CA 02148107 2001-08-09
passage for introducing dry air into said passage for air
circulation by inhaling atmospheric air.
Brief Description of the Drawings
Fig. 1 is a system drawing of an air refrigerant ice
forming equipment according to the invention showing an
arrangement of various instruments;
Fig. 2 is a perspective view of an air to air heat
exchanger;
Fig. 3 is a cross-sectional view of a shell and tube
heat exchanger;
Fig. 4 is a transverse cross-sectional view of an air
compressor;
Fig. 5 is a view for showing an arrangement of the air
compressor, a motor and an air expander;
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Fig. 6 is a transverse cross-sectional view of an air ex-
pander;
Fig. 7 is an enlarged partial view of a one-way clutch;
Fig. 8 is a view for showing an arrangement of the air
compressor, a heat engine for cogeneration purpose and the air
expander;
Fig. 9 is a plan view of a course for playing bobsleigh or
luge;
Fig. 10 is a piping layout of a heat exchanger for ice
formation;
Fig. 11 is a plan view of piping of the heat exchanger for
ice formation;
Fig. 12 is a cross-sectional view of a linear portion of
2 0 the playing course;
Fig. 13 is a cross-sectional view of a curved portion of
the playing cour:;e; and
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21481 ~D7
Fig. 14 is a cross-sectional view of a curved portion of
the playing course provided with a cold air injector.
Preferred Embodiment of the Invention
Fig. 1 is a system drawing of an air refrigerant ice form-
ing equipment according to the invention showing an arrangement
of various instruments and a flow of air. As shown in Fig. 1,
the ice forming equipment according to the invention comprises
a closed passage for air circulation incorporating an air com-
pressor 1, a compressed air cooler 2 for cooling the air com-
pressed by the ~~ompressor 1 with heat transfer media outside
the refrigeration cycle, an air expander 3 for expanding the
air which has passed through the cooler 2 to provide cold air
and a heat exchanger 4 for ice formation using the cold air
1 $ which has passed the air expander 3, in the indicated order
along the flow of= air.
The ice forming equipment according to the invention fur-
ther comprises a heat exchanger 5 for heat recovery wherein the
air before entering the air expander 3 is heat exchanged with
the air which has passed through the heat exchanger 4 for ice
formation. The air whose cold heat has been recovered in the
heat exchanger 5, is then returned to the air compressor 1 via
a return pipe 6.
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214810~~
The heat exchanger 5 for heat recovery is an air to air
heat exchanger as shown in Fig . 2 . In the heat exchanger 5,
air passages lE~ and the other air passages 17 are vertically
alternately formed in a plurality of clearances formed by a
plurality of plates 15. Each air passage 16 or 17 is divided
into a plurality of narrow passages 18 or 19 in order to
enhance the effectiveness of the heat exchanger. Through the
air passage 16 (or 17) air which has been compressed by the
compressor 1 is caused to pass, while through the air passage
17 (or 16) air which has come from the heat exchanger 4 for
ice formation i;s caused to pass. The warm air from the com-
pressor 1 is cooled by heat exchange with the cold air from the
heat exchanger ~~. Whereas the cold air coming from the heat
exchanger 4 for ice formation is warmed and thus, the tempera-
ture of air returned to the air compressor 1 via the return
pipe 6 is raised. As a result, the coefficient of performance
of the refrigerav~ion cycle is enhanced.
The compre~;sed air cooler 2 for cooling the air coming
2 0 from the compressor 1 comprises two heat exchangers 2A and 2B.
The heat e~:changer 2A can be a shell and tube heat ex-
changer, as shown in Fig. 3, which comprises a shell 20 and a
plurality of U ~:ubes 21 incorporated in the shell 20. The
2 5 shell 20 is provided with a water inlet 22 and a water outlet
8
~.~4~~ 0~
23 at one end thereof. The water inlet 22 is communicated with
the water outle~~ 23 by means of the U tubes 21. The shell 20
is further provided with an air inlet 24 and an air outlet 25'
With the s:zown shell and tube heat exchanger 2A, cooling
water is introduced from the water inlet 22, caused to pass
through the U tubes and withdrawn from the water outlet 23. In
the winter season usual tap water may used as the cooling wa-
ter. The compressed air from the compressor 1 is introduced
through the air inlet 24 into the inside of the shell 20 and
withdrawn from t:he air outlet 25'. Thus, the compressed air is
cooled by heat exchange with the cooling water in the inside of
the shell 20.
The heat exchanger 2B is an air to air heat exchanger,
which may be of the same type as the heat exchanger 5 for heat
recovery shown in Fig. 2. Cooling air usable in the heat ex-
changer 2B must be of a low temperature. In the winter season
ambient atmospheric air can be used as such as the cooling air.
The air compressor 1 is -for forcibly compressing air of
atmospheric pressure by means of a rotating power of a power
means 7 to provide compressed air, for example, having a pres-
sure of 2 atmospheres. The air compressor 1 can be a bisexual
2 5 screw type compressor whose structure in itself is known in the
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21~8~~'~
art. The biaxual screw type compressor, as shown in Figs. 4
and 5, includes a male rotor 25 having screw vanes and a female
rotor 27 having screw grooves which engage each other. By ro-
tation of the rotors in the opposite directions air undergoes
volume changes in the screw grooves and is compressed. A shaft
26 of the male rotor 25 and a shaft 28 of the female rotor 27
are in gear by means of gears 29 and 30 so that they may rotate
in the opposite directions. The rotation of the power means 7
is transmitted to the shaft 26 and the rotors 25 and 27 are
caused to rotate in the opposite directions. Air inhaled
through a suct_Lon inlet 31 is gradually compressed by the rota-
tion of the rotors 25 and 27 to a pressure of about 2 atmo-
spheres and exhaled through an outlet 32. The power means
shown in Fig. 5 is a motor.
The air expander 3 is a biaxual screw type air expander
having a structure symmetric to that of the air compressor 1,
as shown in Figs,. 5 and 6. A shaft 36 of a male rotor 35 and a
shaft 38 of a female rotor 37 are in gear by means of gears 39
2 0 and 40 so that they may rotate in the opposite directions. The
compressed air introduced into the air expander 3 through an
inlet 41 causes the rotors 35 and 37 to rotate by its pressure
and the air itself is adiabatically expanded to a pressure
slightly higher than the atmospheric pressure and its tempera
10
ture is decreased. The cold air so formed is exhaled through
an outlet 42.
The shaft :36 of the male rotor 35 of the air expander 3 is
coupled to a driving shaft 43 of the power means 7 via a one-
way clutch 44.
The one-way clutch 44 includes, as shown in Fig. 7, an
outer ring 46 and an inner ring 47 and a plurality of cams 45
disposed in an ~innular space between the outer and inner rings
46 and 47. The cams 45 are arranged obliquely against a radial
direction common to the outer and inner rings 46 and 47. By
this oblique arrangement of the cams 45, rotation can be trans-
mitted one-way between the outer and inner rings. The struc-
ture of the one-way clutch 44 itself is well known in the art.
By coupling the rotor axis 36 of the air expander 3 with the
driving shaft 43 of the motor 7 via the one-way clutch 44, the
rotating energy of the rotors 35 and 37 of the air expander 3
can be transmitted to the driving shaft 43 of the motor 7 and
2 0 recovered as a part of the driving power for the air compressor
1.
As shown in Fig. 8, the driving power for the air compres-
sor 1 may be obtained from a heat engine 50 for a cogeneration
purpose, that is from a driving shaft 51 of an electric genera-
2 S for 50 . When the air compressor 1 is driven by the power of
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the heat engine 50, the driving shaft 51 of the heat engine 50
is coupled to t=he driving shaft 2 6 of the compressor 1 via a
variable speed dear 52.
In the heat engine 50, a hot exhaust gas obtained by com-
bustion of fuel is sent to an exhaust gas boiler, from which
high pressure steam is obtained. Whereas the used exhaust gas
is heat exchanged with cooling water and thereafter exhausted
outside the system. Warm water is obtained from the cooling
water of the heat engine 50. The power for driving the air
compressor 1 is obtained from an exhaust gas turbine of the
heat engine 50 for cogeneration purpose.
The surplus, power of the heat engine 50 may be used as a
power for electric generation or as a power for driving other
power machines. Thus, the rotating power of the heat engine 50
is fully utilized as a whole, primarily for operating the ice
forming equipment according to the invention and the remaining
for accumulation of electricity or other purposes in accordance
2 0 with particular conditions for driving the ice forming equip-
ment .
The heat exc=hanger 4 for ice formation is a heat exchanger
for forming ice layers on outer surfaces thereof by passing
therethrough cold air which has been formed by the air expander
3.
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214810'
The heat exchanger 4 for ice formation is buried beneath
the ice level, for example of an ice course for playing bob-
sleigh or luge or of an ice rink for playing ice skate or ice
hockey for a purpose of forming necessary ice layers on the
outer surfaces ~~f the heat exchanger 4. The heat exchanger 4
for ice formation may be composed of a plurality of pipes
arranged in accordance with the desired particular position and
shape of the ice layers. Facilities for playing ice sports may
be provided with the heat exchangers for ice formation in the
form of an exter.~,ded surface coil heat exchanger or in the form
of a plane heat exchanger comprising a heat conducting material
having a plurality of pipes buried therein.
Fig. 9 shows a course 53 for playing bobsleigh or luge.
The illustrated course 53 having a length of about 1.3 kilome-
ters is divided into 7 parts 1 to 7, each part having an indi-
vidually controlled ice forming equipment. In Fig. 9, solid
double circles indicate the positions where the ice forming
2 0 equipment are disposed. Passages for air circulation of the
adjacently disposed ice forming equipment are connected to each
other by means of a by-path so as to back up a trouble which
may be caused when one of the adjacent equipment gets out of
order.
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214810'
The course 53 begins at a starting point 53a and ends at a
finish point S~~c. Slightly downstream of the starting point
53a there is provided a starting point 53b for junior. Between
the starting po::nts 53a, 53b and the finish point 53c, there is
provided a passage 54 for carrying back vehicles from the fin-
ish point 53c tc> the starting points 53a, 53b.
Fig. 10 is a piping layout of a heat exchanger 4 for ice
formation buried in the course 53, and Fig. 11 is a plan view
of the piping of the heat exchanger 4 for ice formation. On
one side of the course there are provided a cold air supply
pipe 55a and a cold air return pipe 56b, while on the other
side of the course there are provided a cold air supply pipe
55b and a cold air return pipe 56a. One end 57a of the cold
air supply pipe 55a is communicated with the air expander,
while the other end 58a of the cold air supply pipe 55a is
closed. Likewise, one end 57b of the cold air supply pipe 55b
is communicated with the air expander, while the other end 58b
of the cold air ;supply pipe 55b is closed. The cold air return
2 0 pipes 56a, 56b are U-shaped pipes with one end 59a, 59b commu-
nicated with the heat exchanger for heat recovery and the other
end 60a, 60b clo:>ed.
The cold ai:r supply pipe 55a on one side of the course 53
2 $ makes a pair to i~he cold air return pipe 56a of the other side
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214507
of the course 53. Likewise, the cold air supply pipe 55b on
the other side of the course 53 makes a pair to the cold air
return pipe 56b of one side of the course 53. The cold air
supply pipe 55a and return pipe 56a making a pair to each other
S are communicated by a plurality of ice forming pipes 61a dis-
posed in para7.le1 across the course beneath the level of ice.
Likewise, the cold air supply pipe 55b and return pipe 56b mak-
ing a pair to each other are communicated by a plurality of ice
forming pipes 61b disposed in parallel. As shown in Fig. 10,
the ice formin~~ pipes 61a and 61b are arranged alternately.
The cold air prepared in the air expander 3 is divided
into two which are respectively introduced into the cold air
supply pipes 55a, 55b through their open ends 57a, 57b. Since
the other ends ~8a,~ 58b of the supply pipes 55a, 55b are
closed, the co._d air supplied is caused to pass through the ice
forming pipes 61a, 61b, recovered in the cold air return pipes
56a, 56b, combined together and sent into the return passage 6.
2 0 Fig. 12 i:; a cross-sectional view of a linear portion of a
course for playing bobsleigh provided with an ice forming
equipment according to the invention. In Fig. 12, the refer-
ence numeral fi5 designates a on re base; 66 a concrete
plate; and 67 a heat insulating mortar layer. On both sides of
2 5 the course side covers 68a and 68b are respectively provided.
214~10'~
Inside the side cover 68a there are contained the cold air sup
ply pipe 55a, the cold air return pipe 56b and a tap water pipe
69. Inside the side cover 68b there are contained the cold air
supply pipe 55b, the cold air return pipe 56a and a warm water
pipe 70.
On the heat insulating mortar layer 67, a plurality of ice
forming pipes 61a communicating the cold air supply pipe 55a
and return pipe 56a and a plurality of ice forming pipes 61b
communicating th~~ cold air supply pipe 55b and return pipe 56b
are alternately disposed in parallel across the course as shown
in Fig. 11. Upper surfaces of the ice forming pipes 61a and
61b are covered by a heat conducting mortar layer via a wire
mesh. The heat ~~onducting mortar layer contains metallic pow
1S der dispersed therein.
The cold ai:r prepared by the air expander 3 is sent into
the cold air supply pipes 55a, 55b disposed inside the side
covers 68a, 68b. The cold air is then caused to pass through
2 0 the ice forming pipes 61a, 61b buried in the course, recovered
in the return pipes 56a, 56b, caused to pass through the heat
exchanger 5 for heat recovery and the return passage 6 and re-
turned to the air compressor 1.
16
214~1~'~
If desired, the ice forming equipment according to the in-
vention may be designed so that a part of the cold air prepared
by the air expander 3 may be discharged through an sir dis-
charge port 8 which comprises a valve or damper 9 and a nozzle
10 (see Fig. 1). By bringing the discharged cold air in con-
tact with water, it is possible to form a desired quantity of
ice at an intended place of the course.
In a case wherein a part of the circulated air is dis-
charged outside the refrigeration cycle, an amount of atmo-
spheric air corresponding to the discharged amount of air must
be sucked into the refrigeration cycle . For this purpose, a
port 12 for sucking atmospheric air provided with a valve or
damper 11 is connected to the return passage 6 on its way from
the heat exchancrer 5 for heat recovery to the air compressor 1,
as shown in Fig. 1. By properly operating the valve or damper
11, a necessary amount of atmospheric air can be sucked into
the closed passage for air circulation.
2 0 In a case ~~herein atmospheric air is introduced into the
refrigeration cycle a problem arises as to the removal of mois-
ture of the introduced atmospheric air. The problem can be
solved by providing an air dehumidifier 13 upstream of the air
compressor 1. By means of the air dehumidifier 13, dry air sub-
2 5 stantially free from moisture can be introduced into the pas-
17
2~~~.~ 07
sage for air circulation. As to the air dehumidifier 13, dry
dehumidifiers using a hygroscopic agent such as silica gel are
conveniently used. Suitable dry dehumidifiers include a
Munter's dehumidifier (rotary dehumidifier having a function of
S reproducing the spent hygroscopic agent) and a two-tower
dehumidifier wherein dehumidification of air and reproduction
of the spent hygroscopic agent are alternately carried out
(Fig. 1 illustrcites a two-tower dehumidifier) .
Fig. 13 is a cross-sectional view of a curved portion of a
course for playing bobsleigh provided with an ice forming
equipment according to the invention. The basic construction
of the curved course is substantially the same as that of the
linear course shown in Fig. 12. The reference numeral 75 des-
1S ignates a concrete base; 76 a concrete plate; and 77 an adia-
batic mortar layer. The heat insulating mortar layer 77 has an
L-shaped cross-:section so as to form a bank. On both sides of
the course side covers 78a and 78b are provided. Inside the
side cover 78a there are contained the cold air supply pipe
2 0 55a, the cold air return pipe 56b and a tap water pipe 79.
Inside the side cover 78b there are contained the cold air sup-
ply pipe 55b, the cold air return pipe 56a and a warm water
pipe 80. On the, heat insulating mortar layer 77. a nlura Wt
of ice forming pipes 61a communicating the cold air supply pipe
25 55a and return pipe 56a and a plurality of ice forming pipes
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61b communicating the cold air supply pipe 55b and return pipe
56b are alternately disposed in parallel across the course.
In the example illustrated in Fig. 13, an air discharge
port 8 is provided for discharging cold air from the cold air
supply tube 55b. To the air discharge port 8 there is con-
nected a nozzle B2 via a flexible tube 81.
Thus, a course keeper 83 can put the course in good condi-
tion by injecting a part of the cold air from the cold air sup-
ply tube 55b through the nozzle 82 via the air discharge port 8
and the flexible tube 81 thereby making up ice at an intended
place of the sur:Eaces of the course. The ice making up can be
carried out more effectively by injecting the cold air together
1$ with an appropriate amount of water taken from the tap water
pipe 84 disposed inside the side cover 78b. Particularly, in
curved portions of the course as shown in Fig. 13 and those
portions of the course suffering from solar radiation, the
course keeper 83 can skillfully put the course in good condi-
2 0 tion by utilizing the cold air injected from the nozzle 82.
For example, he c:an spray water taken from the tap water pipe
84, freezing the sprayed water to ice fog and blowing the ice
fog against a portion of the course where ice must be supple-
mented. Alternatively, he can form a film of water on a por-
t 5 tion of the course where ice must be supplemented and freezing
19
2~4~.~07
the film of water by blowing the cold air from the nozzle 82
against the fi.l.m of water. Furthermore, by mixing cold air
taken from the cold air supply pipe 55b with water taken from
the tap water pipe 84 and blowing the mixture against a portion
of the course where ice must be supplemented, an ice layer con-
taining an appropriate amount of air which is best suitable for
playing bobsleic~h or luge may be formed on a surface of the
course.
1'0 Warm water taken from the warm water pipe 80 may be uti-
lized to melt ice on an intended portion of the course and to
melt snow on an intended portion of the facility. For example,
snow fallen and ,accumulated on the passage 54 of Fig. 9 may be
melted away by the warm water so that a truck may readily run
on the passage to transport vehicles from the finish point to
the start point.
Since a course for playing bobsleigh or luge is snaky in
various directions, the required cooling capacity greatly dif-
2 0 fers from portion to portion. Depending upon the direction and
position, sunny or windy portions require a higher cooling ca-
pacity than other portions. For portions of the course requir-
ing a high cooling capacity, it is advantageous to take out
cold air from the cold air pipe 55a and by means of a duct 85
2 S and to inject the cold air through an injector 86 against the
2I4~10~
surface of the course, as shown in Fig. 14. Such cold air in-
jectors 86 are appropriately provided at portions of the course
where increase cooling capacities are required. Fig. 14 is the
same as Fig. 13 except that the cold air injector 86 is substi-
tuted for the nozzle 82 of Fig. 13 . In Figs . 13 and 14, the
same reference numerals designate the same parts.
Various dirnensions of an ice forming equipment according
to the invention in carrying out ice formation in winter in a
facility for playing ice sports can be as follows:
Area for ice formation in a facility:
4500 m2,
Maximum load for ice formation of the facility:
350 kcal/hr.m2,
Average load for ice formation of the facility:
150 kcal/zr.m2,
Necessary rate of flow of air:
3000 m3/m_n.,
District and period of operation:
2 0 3 months i=rom December to February in Japan,
Average temperature of tap water:
5 °C . , and
Average temperature of atmospheric air:
6.4 °C.
21
2.~4~I0'~
Under the conditions as noted above, the temperature of
cold air suppl_Led to the heat exchanger 4 for ice formation
and the temperai:ure of the air leaving the heat exchanger 4 for
ice formation are set -45 °C. and -15 °C., respectively and the
surface of the ice formed is maintained at a temperature from
-1°C. to -3°C. For this purpose the air refrigerant ice form-
ing equipment may be operated under the following conditions as
shown in Fig. 1.
The air compressor 1 is operated to provide a compressed
air having a temperature of 88 °C. and a pressure of 2 atmo-
spheres. In the heat exchanger 2A, tap water having a tempera-
ture of 5 °C. is caused pass and warmed to a temperature of the
order of 60 °C. In the heat exchanger 2B, atmospheric air hav-
ing a temperature of 6.4 °C. is caused pass and warmed to a
temperature of the order of 40 °C. By the heat exchange in the
heat exchangers 2A and 2B the compressed air is cooled to a
temperature of about 20 °C. The warm water and air obtained in
the heat exchangers 2A and 2B may be utilized for purposes of
2 0 heating or keeping warmth in the facility. The air expander 3
provides cold air having a temperature of -45 °C. and a pres-
sure slightly higher than the atmospheric pressure (for example
1.1 atmospheres) while recovering the power of the air compres-
sor 1. The cold air is sent to the heat exchanger 4 for ice
2 5 formation and utilized for forming ice under the conditions de-
22
~~48i t~~
scribed above. Air having a temperature of -15 °C. which has
left the heat exchanger 4 for ice formation is sent to the heat
exchanger 5 for heat recovery where it is warmed to a tempera-
ture of 15 °C. arid thereafter returned to the air compressor 1.
Thus, there is formed a refrigeration cycle having a re-
frigeration capacity of 7.32 kcal/kg of dry air and a coeffi-
cient of performance of 0.8. The obtained warm product (warm
water and warm a:ir) has a heat quantity of 16.43 kcal/kg with a
coefficient of performance of 1.8. Thus, the overall coeffi-
cient of performance of the refrigeration cycle is 2.6.
tnlhen a driving power for the air compressor 1 is obtained
from the driving shaft 51 of the heat engine 50 for a cogenera-
tion purpose, as shown in Fig. 8, letting the energy of fuel
supplied to the :heat engine be 1, in a case of a heat engine
wherein the output of the driving shaft of the heat engine is
0.35 and the heat quantity recovered by the steam and warm wa-
ter formed by the heat engine is 0.45, since the ice forming
2 0 equipment provides a refrigeration capacity of 0.28 and heat
recovery of 0.63, the total heat quantity obtained by both the
cogeneration system and the ice forming apparatus is
0.45 + 0.28 -E 0.63 = 1.36.
23
2.~~~~~~
This value of heat quantity is well comparable with the overall
efficiency of a prior art engine driven heat pump using fron as
a working medium which overall efficiency is
0.35 x 3.0 + 0.45 = 1.50
wherein 3.0 is a coefficient of performance of the heat pump.
This high value of heat quantity has not heretofore been
achieved by an air refrigerant ice forming apparatus using air
as a working medium, and is higher than a coefficient of
performance in terms of a primary energy of a prior art
electric refrigerator using fron as a working medium whose
coefficient of performance is
0.35 x 3.0 =- 1.05
wherein 0.35 is an efficiency of a terminal in receiving a com-
mercial electric power.
When a driving power for the air compressor 1 is obtained
from an exhaust c~as turbine of the heat engine 50 for cogenera-
tion purpose, all. the shaft output of the heat engine 50 can be
transmitted to the generator for cogeneration purpose.
2 0 Furthermore, the shaft output of the heat engine 50 may be uti-
lized as a power source for transporting passengers and goods
in the facility. In this case if an exhaust gas of the heat
engine has a temperature of 580 °C. and a pressure of 2 atmo-
spheres, an exhaust gas leaving the turbine has a temperature
2 $ of 430 °C. and a pressure of 1 atmosphere, and an exhaust gas
24
2148I0~
leaving the turbine has a temperature of 250 °C. and a pressure
of 1 atmosphere, letting the energy of the supplied fuel be 1,
there will be realized an output of the shaft of about 0.25, an
output of the exhaust gas turbine of about 0.1 and a heat quan-
tity recovered in the steam and warm water of about 0.32.
Accordingly,, when the driving power for the air compressor
1 is obtained from an exhaust gas turbine of the heat engine 50
for cogeneration purpose, since the refrigeration cycle accord-
ing to the invention provides a refrigeration capacity of 0.08
and a quantity of recovered warm heat of 0.18, there will be
obtained a driving power of 0.25 and a quantity of heat of
0.32 + 0.08 + 0.18 = 0.58.
These results are well comparable with values of the driving
power and quantity of heat which have been achieved by an ex-
fisting cogenerat_Lon system wherein a heat engine for cogenera-
tion is combined with a refrigerator using fron or ammonia as a
working medium. ~rhus, according to the invention, in spite of
the fact that air is used as a working medium in the refrigera-
2 0 tion cycle concerned, there can be constructed an energy saving
system highly efficient in recovering cold heat, warm heat and
power.
From the heat exchangers 2A and 2B of Fig.l warm water and
2 5 warm air are obtained. Piping can be arranged so that the warm
water and air may be transferred to audience seats to keep
warmth. The warm water pipe 70 of Fig. 12 and the warm water
pipe 80 of Fig. 13 are connected to piping arranged so that
warm heat may be' supplied close to feet of audience and con-
s cerned people who are standing near the course. The warm water
taken from the pipes 70 and 80 may be further utilized to melt
ice at the time of repairing the course.
Furthermore, by installation of a warm air duct for send-
ing the warm air to a temporary stand for audience or walking
roads in the facility, the environment in the facility may be
kept in good condition even in the severe winter season . The
warm water may b~~ further utilized to melt snow in the passage
54 of Fig. 9 thereby to facilitate the transporting of vehicles
from the finish point 53c to the starting points 53a, 53b.
The specific example described hereinabove relates to an
application of t:he invention to a facility for playing ice
sports includes a course for playing bobsleigh or luge which
2 0 are played outdoor. The invention is also applicable to a fa-
cility (ice rink) for playing ice skate or ice hockey which are
played indoor. Ir,~ the latter case, the heat exchanger 4 for ice
formation may be constructed in various variations. For exam-
ple, in order to strengthen the cold air pipe or to enhance its
2 S thermal conductivity, it may be buried in the. heat conducting
26
mortar, it may be constructed in the form of a finned coil, or
it may be formed in the form of a panel-type heat exchanger.
Furthermore, by composing the ice forming pipes of the
heat exchanger ~~ for ice formation of a first group of ice
forming pipes 61.a communicating the cold air supply pipe 55a
and the cold air return pipe 56a and a second group of ice
forming pipes 61b communicating the cold air supply pipe 55b
and cold air return pipe 56b and alternately arranging the
first and second groups of ice forming pipes 61a and 61b in
parallel across the course, as shown in Figs. 10 and 11, all
ice surfaces of the ice rink or course of the facilities for
playing ice sports can be uniformly cooled.
Thus, the refrigeration cycle according to the invention
exhibits an exce:Llent coefficient of performance due to recov-
ery of heat and power as described herein, in spite of the fact
that air is used as a working medium. Since cold heat neces-
sary for ice formation is obtained using air as a working
2 0 medium, the ice forming equipment according to the invention is
completely free from the problem of environmental pollution.
To the contrary, a part of the cold air acting as a working
medium can be discharged outside for a purpose of ice forma-
tion. In this case ice surfaces of an intended configuration
2 S can be readily formed. In addition, since the heat of compres-
27
2148107
sion of the air compressor used in making cold air can be re-
covered in the form of warm air and water which are in turn
utilized for forming a warm environment, the power energy for
operating the refrigeration cycle can be effectively recovered.
$ Construction of the equipment according to the invention in a
particular facility for playing ice sports is simple and easy,
since it only re~~uires arrangement of piping for air and water.
The ice forming equipment constructed in a certain facility can
be easily repaired. Furthermore, if the refrigeration cycle
according to the invention is combined with a heat engine for
cogeneration purpose, comprehensive energy saving can be
achieved, whereby burden of high running cost, which is a de-
fect of existing air refrigerant ice forming equipments, can be
greatly reduced.
28
