Patent GB-1090332-A (GB)
Title: Absorption refrigeration system control
IPC: F25B15/06
Filed: 1964-11-06
Abstract: 1,090,332. Refrigerating. WORTHINGTON CORPORATION. Nov. 6, 1964 [Jan. 17, 1964], No. 45286/64. Heading F4H. In an absorption refrigeration system of the type employing water as refrigerant and a salt solution as absorbed, and in which concentrated solution leaving the generator is heat exchanged with a first stream of unconcentrated solution from the absorber, the concentrated solution is diluted at part load by a second stream of unconcentrated solution originating separately from said first stream at the absorber. As shown, in conduit 32 having its inlet arranged above the floor of the absorber sump 22 conveys weak solution from the absorber 11 to the generator 12 via the tube side 30 of the liquid heat exchanger 31. A second conduit 54 conveyes weak solution from sump 22 to the solution circulating pump 51 and a further line 56 is arranged to pass weak solution from the sump to a receiver 57 under the control of a valve 611, the latter being adapted to open during low load conditions as determined by sensing the outlet temperature of water cooled in the evaporator 14. A line 59 is adapted to supply weak solution from receiver 57 to a chamber 41 which receives strong solution from the generator and supplies it to the shell side of heat exchanger 31. The resultant dilution of the strong solution prevents crystallization from occurring in the heat exchanger at low loads. A further line 58 is adapted to supply weak solution from receiver 57 to a chamber 47 which is arranged to receive strong solution from the heat exchanger 31 and to discharge through line 40 to the solution circulating pump 51. Since the flow through line 54 to pump 51 and the flow through the pump itself are substantially constant, flow through line 40 is also constant and hence any flow occurring in line 58 reduces by an equal amount the flow from the generator to the absorber. The diameter of line 58 is greater than that of line 59 so that the rate of flow in line 58 increases more rapidly than that in line 59 as valve 61<SP>1</SP> progressively opens; this avoids excessive dilution of the strong solution passing through the heat exchanger 31. Line 59 may be arranged to discharge directly into the shell side of exchanger 31 (Fig. 3, not shown) and the inlet of line 59 may be arranged below that of line 58 in the receiver (Fig. 7, not shown). In the modification of Fig. 4 (not shown) receiver 57 is omitted and the load-responsive valve 67 is located in the line 66, 68 transmitting solution to chamber 47, the diluting stream for chamber 41 being tapped off via line 72 from the line 69, 71 conveying weak solution to the pump. Line 72 includes a load-responsive flow controlling valve 73. Alternatively the diluting stream may be obtained from the pump discharge side (Fig. 5, not shown). In a further modification (Fig. 6, not shown) the line 83 carrying the diluting stream may branch off from the line 79, 82 carrying solution to chamber 47 and may include a restriction 83<SP>1</SP> while in the embodiment of Fig. 8 (not shown) the load-responsive valve 104 is disposed in the line 105, 106 conveying solution from the absorber to the generator, the diluting stream line 100 being arranged to communicate directly with the sump 101 at a point substantially above its floor.