Abstract: A control device for an absorption system interrupts a pneumatic signal controlling the demand for chilled water by utilizing a single port direct acting controller to which is fed a chilled water return temperature signal. The single port direct acting controller provides a continuous signal to control the heating source utilized in providing the chilled water as a real time function of the temperature of the chilled water returning from an associated cooled building, as well as the internal controls of the absorption system. Thus, the control device provides an optimal decision value, factoring all dynamic operating variations which affect chilled water return temperature, for the control of the heating source utilized in providing chilled water, thereby reducing the fuel consumption of the absorption refrigeration system. Alternatively, a dual port direct acting controller is added, to which are fed an outdoor air humidity signal and an outdoor air temperature signal.

Abstract: The control system interrupts the pneumatic signal controlling the demand of chilled water by utilizing a dual port direct acting controller to which are fed an outdoor air humidity signal and outdoor air temperature signal. The dual port direct acting controller provides a signal to control the heating source for the chilled water as a function of the outside air temperature and outside air humidity as well as the internal controls of the absorption system. Thus, the control system provides an optimal decision value for the respective climate range of conditions for the control of the heating source thereby reducing the fuel consumption of the absorption refrigeration system.