GB1382428A - Air conditioning systems - Google Patents

Abstract

1382428 Ventilation and air conditioning CARRIER DRYSYS Ltd 18 July 1972 [6 Aug 1971] 37126/71 Heading F4V [Also in Division G3] A temperature control system for a plurality of thermally similar zones includes temperature sensors in each zone and means to preset the required temperature of that zone, the temperature or volume of air in a common duct to the zones being controlled, upon sensing temperatures in all the zones below the preset temperatures, according to the nearest sensed temperature in a zone relative to its preset temperature, so as to restore the temperature in that zone to its preset value. As shown, air is circulated through air conditioning plant 6-10, including a humidifier and cooler and through a flow control damper 16 and heater 14 to a common duct 5 feeding air distributing units 4 in each zone A, B, C. The zones also have heaters 18 controlled by thermostats 20, and temperature sensors 17, e.g. providing temperature dependent discrete, pneumatic or, as shown, synchronized pulses via OR gates 24 (or shift registers 26, Fig. 2, not shown) to control steam valve 21 to heater 14 and damper 16. Initially, with all the zones below a common preset value of 70‹ F. set on sensors 17, damper 16 is closed and valve 21 opened to provide air at 100‹ F. to each zone, the heating being boosted by heaters 18. At a temperature of 69‹ F. the heaters 18 are turned off, and control of damper 16 and valve 21 is by pulses from the sensor 17 in the zone whose temperature is nearest the preset value of 70‹ F., until the temperature in that zone is at the preset value. Heater 14 may use " low grade " heat, e.g. hot water, gas or air from a heat-reclamation device. Flow control may be effected by control of fan 13 to replace damper 16. If the system is used. in hot climates, heaters 14, 18 may be omitted.