ES314383A1 - Heating and cooling system - Google Patents

Abstract

In a refrigeration system of the type in which the compressor 20 is driven by a turbine 14 which receives steam from a steam generator 12 and discharges to a steam condenser 16, a line 341 is provided for supplying variable amounts of refrigerant vapour from the evaporator 24 to the steam condenser for varying the pressure in, and hence the heat output of, the condenser. The latter is disposed within a space 21 serving as the refrigerant condenser and includes two sets of cooling coils 34 and 41, the former being connected in series with the cooling coil 117 of the refrigerant condenser for receiving water from a cooling tower and the latter being supplied with a fluid to be heated. The refrigerant vapour is discharged into condenser 16 through a nozzle 106 in such a manner that it blankets coil 34 so that the steam condenser pressure and temperature rise and more heat is supplied to coil 41. The rise in pressure also causes turbine 14, and hence compressor 20, to slow down to reduce the cooling capacity of the refrigeration system. A modulating valve 35 in line 341 regulates the amount of refrigerant vapour supplied to condenser 16 in accordance with the temperature of the chilled water circulating in a coil 128 disposed in the evaporator. Refrigerant condensed in 21 is cooled by water from the cooling tower in a heat exchanger 22 then forwarded to a pan 127 in the evaporator via a float valve 23 and line 124. Pan 127 is disposed above a water sump 132 from which water is withdrawn by pump 38, cooled in a heat exchanger 181 by incoming water to be heated and returned to the sump via a jet pump 39 which withdraws refrigerant vapour at a constant rate through a lime 40 from a chamber 86 in communication with condenser 16. Water from chamber 86 is forwarded to the steam generator 12 by pump 17 and make up water is supplied to chamber 86 through line 401, which communicates with the outlet of pump 38, under the control of a float operated valve 113. The bearings 18 of the turbo-compressor are lubricated by water supplied from steam generator 12 through line 181, the used water together with any refrigerant leakage being supplied through line 76 to chamber 86. Water collecting on the surface of the pool of refrigerant in pan 127 flows through opening 134 into the sump 132. At extremely low cooling loads surging of the compressor is prevented by providing a hot-gas by-pass line 42 between the condenser 21 and line 124, and operating a valve 421 in line 42 in response to steam condenser pressure or temperature. If the system is required to provide only cooling, the pump 411 supplying the liquid to be heated is turned off. If only heating is required the pump 27 supplying the condensers with cooling tower water is turned off and valve means 43 in the steam supply line are operated to by-pass the turbine and render the refrigerating cycle inoperative. In these circumstances the pressure of the refrigerant in evaporator 24 rises and a valve 190 in a line 185 communicating the evaporator with a storage vessel 186 so that the refrigerant is displaced to said vessel and is condensed therein by a coil 188 through which air is drawn by blower 180 for supply to the burners 175 of the steam generator. The refrigerant employed is preferably octafluorocyclobutane. In a modification (Figs. 5 and 6, not shown) the water to be heated is passed through a tube bundle (143) in a heat exchanger (141) which is mounted on the steam generator (12a) and receives steam condensate from the steam condenser (16a) through a condensate line (103a). The pressure in the condenser (16a) is varied as in the previous embodiment so that a varying amount of condensate is supplied through the condensate line, the tube bundle (143) being mounted in an open topped shell (142) so that the steam condensate blankets a variable number of the tubes to prevent them from being heated by steam introduced directly from the steam generator (12a). Condensate is returned from the shell (142) to the steam generator via a conduit (150) having a restriction (151) and the opening (149) in the shell is arranged so that at maximum steam condensate supply approximately 10% of the tubes in the bundle (143) are above the condensate level. In a further modification (Figs. 7 and 8, not shown) the water is heated in a heat exchanger disposed within the shell of a steam generator of the fire-tube type.