Thermal energy system for ice rinks
United States Patent [19} Holmsten [76] Inventor: Richard B. Holmsten, 2127 Dudley Ave., St. Paul, Minn. 55 I08 [22] Filed: May 8., 1974 [2]] Appl. No.: 467,919  
 [ Apr. 22, 1975 Primary E.\&#39;uminer-William .I. Wye  
 [57] ABSTRACT A system for providing a chilled refrigerant to a distribution system disposed immediately below the plane of a skating rink, the system including a compressor, means for delivering compressed refrigerant to first and second condensers, and thence to deliver condensate to a low pressure receiver vessel. Means are provided for passing refrigerant condensate from the low pressure receiver vessel to the distribution system disposed beneath the skating rink. The second condenser includes heat exchange means coupled to a heat distribution system which is disposed beneath the chilled refrigerant distribution system, with means being provided to deliver heated fluid such as ethylene glycol from the heat exchange means to the heat distribution system where heat is extracted therefrom.  
 3 Claims, 1 Drawing Figure [52] U.S. Cl 62/235; 62/260 [51] Int. Cl F25d 23/12 [58] Field of Search 62/235, 260  
 [56] References Cited UNITED STATES PATENTS 3,599,441 8/1971 Sills 62/235 3,831,394 8/1974 Holmsten 62/235 FOREIGN PATENTS OR APPLICATIONS 585,626 10/1959 Canada 62/235 of eutcot.  
 exchange or for the abstracting of thermal energy from areas beneath skating rinks. and further providing means to re-introduce thermal energy generated in the refrigeration cycle into the area beneath the rink distribution system in order to provide a thermal equilibrium free of the danger of deep frost penetration. The system of the present invention provides a means for circulating liquid refrigerant to the area being refrigerated. that is. immediately beneath the plane of the skating rink. and further provides a means therebelow for delivering and circulating heated fluid for the purpose of preventing deep frost penetration in the area beneath the chilled refrigerant distribution system.  
  It is well known that exposure of earth support zones to freeze-thaw cycle. may cause significant heaving of the support zone. Particular problems in this area develop when a large area. such as an ice rink or skating rink has been subjected to frozen temperatures over extended periods of time. In such installations. if the refrigeration system is shut down for any extended period of time for servicing or replacement of components. the subterranean earth support will normally thaw. and this thawing may result in disruption. normally referred to as heaving&#34; of the subterranean support. thereby causing damage to the zone supporting the ice rink per se. As is conventional. a concrete support bed is utilized for this purpose. and any heaving of the bed may. in turn. cause rupture of the piping system which is normally disposed directly within the confines of the support bed. such as for example. the piping being disposed directly within the poured concrete rink bed.  
 SUMMARY OF THE INVENTION The present invention is particularly adapted for use in combination with that certain refrigeration system for ice rinks disclosed and claimed in my US. Pat. No. 3.466.892. dated Sept. 16. 1969. In that patent. a direct refrigeration system is disclosed wherein the chilled refrigerant is passed through the system by means of pumper drums which are coupled directly to the compressors. No secondary refrigerant is required for the system. This system accordingly eliminates the necessity of transmission or circulation of liquid refrigerant at extremely low temperatures. and permits operation of the chilled area at a reasonably constant temperature within the range of between about l5 F. 18 F. This temperature is one which results in an ice surface which is deemed ideal for ice hockey or figure skating. and the system of the present invention accomplishes the desired result with unusually high working efficiency and consequent low energy consumption.  
  Briefly. in accordance with the present invention. the refrigerant is passed through a compressor where it is transformed from low pressure gas to high pressure gas. This material is ultimately passed through a condenser wherein the high pressure gas is transformed in phase so that it is substantially entirely in the liquid phase. Heat is. of course. evolved in the phase transformation and this heat is normally dissipated. A feature of the present invention is the utilization of at least a portion of this heat to warm that area immediately below the chilled area so as to prevent deep frost penetration and ultimate danger of heaving. Specifically. the ice rink zone is provided with a surface for receiving the water to be formed into the ice. with the distribution system and piping being disposed immediately below the rink surface. A thermal insulation barrier is disposed below the refrigerant distribution system. with the thermal heating system being disposed below the thermal insulation. such as. for example. in the subterranean earth support area. In this connection. therefore. it is possible to utilize some of the thermal energy which would otherwise be dissipated into the atmosphere for the purpose of achieving thermal equilibrium in the subterranean support area. thereby achieving a greater degree of stability for the overall installation.  
  Therefore. it is a primary object of the present invention to provide an improved chiller system for ice rinks wherein a portion of the heat which is generated in the refrigeration cycle is utilized for the purpose of stabilizing the subterranean support for the chilled ice rink area.  
  It is yet a further object of the present invention o provide an improved system for the efficient utilization of energy in an ice rink area. with the chilled fluids obtained during the conventional refrigeration cycle being utilized to maintain the ice rink in desired condition. and with the heated fluid obtained during the refrigeration cycle being utilized to enhance the stability of the support zone beneath the rink.  
  Other and further objects of the present invention will become apparent to those skilled in the art upon a study of the following specification. appended claims. and accompanying drawing.  
 BRIEF DESCRIPTION OF THE DRAWING The drawing is a schematic diagram of one typical installation employing the improved system aspects of the present invention.  
 DESCRIPTION OF THE PREFERRED EMBODIMENT In accordance with the preferred modification of the present invention. the refrigeration system generally designated 10 includes compressor 11. the compressor II treating the refrigerant which is being delivered into the area or zone being refrigerated. as well as in other portions of the system including the skating rink shown. The system includes certain other major components including a first condenser IS. a liquid storage vessel 16. a low pressure receiver chamber or vessel 17. and a pair of pumper drums l8 and 19. The individual components are coupled together by means of suitable conduits. as indicated. and as more fully explained hereinafter.  
  Referring to the rink chilling portion of the system. the compressor 11 delivers a pre-selected refrigerant. such as. for example. Freon-22 to main conduit 20. The compressor is driven by any suitable source of power. such as. for example. an electrical power source or an internal combustion engine. Conduit 20 extends to and communicates with the first condenser 15 which is operated in a conventional fashion. The output of the condenser 15 is transmitted by means of the conduit segment 22 and the conduit 23 through a controlled metering valve 24 and thence into the liquid storage vessel 16. Liquid storage vessel 16 is provided with a pair of outlet conduits. these being shown at 26 and 27. Conduit 26 is provided with a pair of control valves. for  
 example gate valves 28 and 29. along with a pressure reducing or demand flow control valve 30. A bypass is provided. as indicated. at 31 to accommodate the system when the valve is not being utilized. valves 28 and 29 being utilized to isolate valve 30 from the system. Outlet 27 extends from the liquid storage vessel 16 to ajuncture point with the liquid storage vessel bypass line 33, the flow in line 33 being controlled by valve 34. Line 27 extends to a second juncture point or fluid divider point as at 55 where the fluid is driven or carried for transmission directly into one of the pumper drums. such as pumper drum 18. for a purpose as will be more fully explained hereinafter or for transmission to the vessel 17.  
  Following its transmission into the low pressure receiver 17. a portion of the liquid transmitted is transformed into the vapor phase. and the remaining material remains in the liquid phase. The liquid is removed from the low pressure receiver 17 by gravity through conduit 36. which is provided with a servicing valve 37, and ultimately into the pumper drum 18. Of course. a suitable conduit 39 may be coupled to conduit 36 in order to carry refrigerant fluid in liquid state on an alternating cycle basis to the second pumper drum 19. Suitable check valves such as are shown at 40 and 41 are utilized to isolate the pumper drums 18 and 19 from the supply conduits 36 and 39 and from the low pressure receiver 17 when the drums are subjected to high pressure. The pumper drums 18 and 19 are each provided with discharge conduits 43 and 44 which. by virtue of the check valves 45 and 46. are effectively isolated. one from the other. while both are coupled to the delivery conduit 48 supplying chilled refrigerant to the rink zone.  
  Conduit 48 is coupled to the trunk distribution head. not shown here. but is the same as that found in U.S. Pat. No. 3.466.892. the header being provided with a plurality of distribution lines such as. for example. the distribution lines 51-51. A refrigerant collecting header is utilized to collect the refrigerant from lines 51-51 and deliver it into line 52 for ultimate return to the low pressure receiver 17. Service valve 53 may be employed along line 52 as required.  
  In order to provide the force necessary to transmit the refrigerant from the pumper drums through line 48 and retain this refrigerant in liquid phase. attention is directed to the output 27 ofthe liquid storage vessel 16. Line 27 couples liquid storage vessel 16 to a juncture point 55. solenoid valve 56 and check valve 57 being interposed along line 27 between the liquid storage vessel l6 and the juncture point 55. Line 58 connects the juncture point to the inlet of the pumper drum 18. A parallel system for providing high pressure to the pumper drum 19, this including conduit 59 which extends between the line 27 and a juncture point 60. A solenoid valve 61 and a check valve 62 are interposed along line 59 for control. Conduit 68 has a segment coupling juncture point to the inlet of pumper drum 19.  
  juncture point 55 is coupled also to a conduit or line 64 which conduit is. in turn. coupled to the low pres sure receiver 17. through check valve 65 and solenoid valve 66 for the purpose of venting drum 18. Similarly, an upper segment of line 68 extends from juncture point 60 to the low pressure receiver 17, this upper segment of line 68 including check valve 69 and solenoid valve 70.  
  As previously indicated. pumper drums 18 and 19 are filled by gravity through lines 36 in the case of pumper drum 18 and a combination of lines 36 and 39 in the case of pumper drum 19. In order to accommodate this gravity fill. and with specific reference to pumper drum 18. conduit 58 functions as a vent during the filling operation. and with solenoid valve 56 in a closed position and solenoid valve 66 in an open position. refrigerant in gaseous phase moves from pumper drum 18 along line 58 to juncture point 55, and thereafter from juncture 55 to the low pressure receiver 17 by way of line 64. In a similar fashion. pumper drum 19 is vented to low pressure receiver 17. When the pumper drum is filled to an upper level as sensed by a float or fluid level sensor 72. the disposition. of solenoid valves 56 and 66 is reversed. and the high pressure fluid from the liquid storage vessel 16 is transmitted directly into the pumper drum 18 by way of line 27 from liquid storage vessel 16 to juncture point 55, and then through line 58 to pumper drum 18. This operation is continued until the level in pumper drum 18 is reduced to the lower level or point indicated by liquid level sensor 73. During the discharge of refrigerant from storage vessel 16 to pumper drum 18. a portion of the fluid in vessel 16 may be transformed to the gaseous phase. When the lower level point is reached in drum 18, the disposition of the solenoid valves 56 and 66 is again reversed. and pumper drum 18 resumes its filling cycle. In a similar fashion. pumper drum 19 is filled and emptied. and preferably the two pumper drums operate alternately in order to provide a substantially continuous flow of chilled refrigerant in liquid phase to the header 50 way of delivery conduit or line 48.  
  Since most fluorinated hydrocarbons such as constitute Freon-22 are completely miscible or compatible with the oils utilized to lubricate the compressor. it is frequently desirable to provide a bleed line to continuously separate the oil from the refrigerant. Thus. the bleed line is provided between the low pressure receiver 17 and a refrigerant-oil separator 76. The separator is provided with a discharge line 77 to carry the separated oil back to an oil receiver 78, and ultimately into the compressor 11 as shown. Line 79 and its check valve 80 are utilized to permit transfer of the liquid refrigerant from the separator 76 to the line 48.  
  Pressure gauge and thermometer indicators are frequently desirable, these being shown for example. along delivery conduit 48 as at 81. It will be appreciated that instrumentation is not essential to the operation of a calibrated system, however for purposes of uniform operation. such instrumentation is normally desired.  
  Attention is now directed to the upper right portion of the drawing wherein a trunk distribution head. not illustrated. is utilized to confine the refrigerant delivered from the pumping drum. the head optionally being provided with a plurality of liquid sub feeder lines. Each liquid sub-feeder line is in turn provided with a plurality of distribution openings. Conventionally. 18 such distribution openings are provided for each liquid sub-feeder line but other numbers may be used. These distribution heads in turn lead to the individual lines 5l51 which extend across the rink refrigeration area. It is important that either the line length of the individual lines extending from the distributor head be substantially equal or that other throttling controls be utilized in order to equalize flow and avoid the provision of warm or cold isolated areas within the rink refrigeration area. It will be appreciated. of course. that other distribution systems may be utilized with the system of the present invention. The distribution system disclosed in U.S. Pat. No. 3.466.892 may be utilized in connection with this system. if desired.  
  The system described finds particular utility in skating rink applications since the chilled refrigerant which is driven through the distribution system is maintained substantially in the liquid state during its transfer therethrough. There is only modest. if any. transformation from liquid to gaseous phase. however. since the refrigerant is exposed to a modest increase in pressure during its movement through the distribution lines. the degree of transformation from liquid to gaseous phase being minimal. Thus. refrigerant entering the distribution head at F. 18 F. will normally leave this distribution head at a temperature of no less than about l2 F. with refrigerant normally leaving the distribution head at a temperature approximately the same as that of its entering.  
  Turning now to the subterranean heating portion of the system. junction point 94 in line permits a portion of the heated gas. at high pressure. to bypass first condenser 15. and be carried to second condenser 96. In the drawing. a second condenser 96 has been illustrated as a heat exchanger. since it does perform this function. The refrigerant gas. at high pressure from compressor 11. therefore passes through second condenser 96 and thence into conduit or line 97. through line segment 98. and thence through conduit 99 through which it is discharged into low pressure receiver 17. The other components along these lines will be discussed later. Coupled to second condenser 96 is a heat exchange system which includes a second system utilizing ethylene glycol or other low temperature refrigerant capability fluid which flows through conduit 100 extending from heat exchanger 96. and thence to lines 102102 which are disposed in a plane beneath the insulation layer. which separates the zone surrounding lines 102 from the rink support area incorporating chilled refrigerant lines 51-51. Following passage through lines 102--l0 2, the ethylene glycol refrigerant which has then been chilled because of exposure to the subterranean environment. is passed through conduit 103. past junction 103A. and thence to the inlet side of normally running circulating pump 104. Exemplary temperatures of the fluid flowing in lines 100, 102, and 103 are illustrated in the drawing. with the heated fluid being at approximately F. and the spent fluid being at a lower temperature of approximately 40 F. or lower. When the subterranean area adjacent conduits or distribution lines 102-102 does not call for heat.&#39;pump 104 may be shut down. thus terminating flow of fluid through the heating lines. An expansion tank 111 may be employed. if desired. in communication with conduit 103 through stand-pipe 112.  
  Turning now to the arrangement of components along line segments 97, 98. and 99, demand valve 108. preferably a solenoid operated demand valve is utilized to control flow of fluid from the heat exchanger 96 to the low pressure receiver l7. &#39;A high pressure trap or float I06 is provided down stream from demand valve 108, thus controlling the delivery of refrigerant into low pressure receiver 17.-  
  In certain skating installations. it is desirable to have a dump-pit for the ice particles which are removed from the rink during re-surfacing. In this connection. pit 115 may be utilized for this purpose. with the pit being heated from the fluid passing through heating conduits 102-102. and thence through conduit 116. Conduit 116 provides the heat necessary to melt and dispose of the ice chips which are deposited in pit 115.  
  While the drawing and description has indicated and suggested that two separate condenser means be provided. such as the condenser means 15 and 96. it will be. of course. appreciated that a single condenser may be employed. with the glycol tranmission system being coupled directly to a single condenser. For purposes of this explanation. therefore. it will be appreciated that a single condenser enclosure may perform dual functions. including the function of heating glycol. It is apparent. however. that individual condenser chambers are desired for purposes of extensive control of the overall system and ultimate economy of the operation.  
 I claim:  
  1. In a refrigeration system for delivering chilled refrigerant directly to a distribution system disposed in a generally horizontal plane beneath a skating rink:  
 a. compressor means having an inlet conduit for receiving gaseous refrigerant at one pressure. and outlet conduits for delivering an output of gaseous refrigerant to said outlet conduits under a relatively higher pressure:  
 b. first and second condenser means each being adapted to receive a portion of said refrigerant output. said first condenser means being adapted to convert said gaseous phase refrigerant to liquid phase refrigerant. and means for delivering said liquid phase refrigerant to a first storage vessel wherein said liquid phase refrigerant is received. at least partially evaporated to achieve a refrigeration affect therein. and maintained therein at a relatively lower pressure;  
 c. means for delivering the refrigerant from said first storage vessel to a skating rink where heat is being extracted;  
 d. said second condenser means having an enclosure means adapted to convert said gaseous phase refrigerant to liquid phase refrigerant and having heat exchange means for extracting thermal energy therefrom;  
 e. thermal insulation means disposed along a generally horizontal plane beneath said chilled refrigerant distribution system: and  
 f. said heat exchange means being coupled to a heat distribution system disposed along a generally horizontal plane beneath said thermal insulation means with means being provided to deliver heated fluid from said heat exchange means to said heat distribution system where heat is abstracted therefrom.  
  2. The refrigeration system as defined in claim 1 being particularly characterized in that said heated fluid is liquid refrigerant.  
  3. The refrigeration system as defined in claim 2 being particularly characterized in that means are provided for discharging spent heated fluid from said heat distribution system to said first storage vessel.