Patent GB-1261104-A (GB)
Title: Air conditioning system and control including control method and means
Inventor: MCFARLAN ALDEN IRVING
IPC: F24F3/044
Filed: 1969-02-20
Abstract: 1,261,104. Heating and cooling buildings; refrigerating. A. I. McFARLAN. 20 Feb., 1969 [20 Feb., 1968], No. 9340/69. Headings F4H, F4U and F4V. In a system for heating and cooling a building having a number of zones some of which may need heating and some of which may need cooling, there are provided two refrigerating units which supply hot and cold water to two coils 16, 32, one in each of two air-treating units, there being means for adding or discharging heat to or from the system and a control responsive to the temperature of the stream of hot water. One unit 2 admits fresh air via louvres 40 and recirculated air via louvres 38, the air passing to the coil 32, through a fan 34, and being delivered from a duct 35. A controller 110 is provided to connect a rise in humidity. The second unit 4 takes in used air, passes it through coil 16, a fan 18, and delivers it via a duct 21. Both units have auxiliary electric heaters 39, 29. Pumps 60, 62 recirculate the fluid through the refrigerating units. A booster heater 17 is also provided. One of the refrigerating units is connected to a cooling tower 13, there being a line 100 to by-pass the tower. Each coil 16, 32 receives hot or cold water or a mixture of hot and cold water via a valve 22, 24 respectively, the valves being controlled by thermostats 20, 52 respectively. Basic control is exercised by a thermostat controller 112 in the hot water line 7 and acts through a controller 114, there being a manually set selector unit 116 that can be set to "Summer" or to one of two "Heat Balance" positions. In the "Summer" position, the controller 114 renders the heat producing components inoperative. When set to one of the "Heat Balance" positions the temperature for which the controller 114 is set may be reset to a higher or lower figure by a thermostat 118 sensing outside temperature. For the other "Heat Balance" position, the thermostat 20 will act to modulate the action of controller 114, thermostat 20 being itself modulated by a controller 120 sensing outside air temperature and the controller 118 is inoperative. Excess heat can be disposed of by admitting more outside air via louvres 40 thereby causing coil 32 to dissipate more heat. Further, if water is passed through a line 73 to by-pass condenser 70 less chilled water is supplied via pipe 3 and the refrigeration load is decreased and there is a corresponding fall in the amount of heat supplied to the system by the condensers. Excess heat is also removed from the system by the increase in outside air since leakage is correspondingly increased and this in turn reduces the amount of heat in the system. In the refrigerating units means is provided for pumping refrigerant from the bottom of the evaporator to sprays in the top of the evaporator to promote evaporation of liquid. A heat exchanger through which water from a cooling tower circulates in heat-exchange relation with the refrigerant gas passing from the top of the evaporator causes condensation of the refrigerant which then returns to the pump for subsequent spraying into the evaporator. By this arrangement the refrigerant performs the cooling function without the necessity for operating the refrigerating unit.