Johnson Controls Tyco IP Holdings Llp

Rachel A Glanzer

Kirk H Drees

Brennan H Fentzlaff

Timothy I Salsbury

John M House

A system for controlling flow of a fluid through a heat exchanger in a heating, ventilation, or air conditioning (HVAC) system includes a flow control device operable to adjust the flow of the fluid through the heat exchanger, temperature sensors positioned to obtain a temperature differential of the fluid across the heat exchanger, and a controller configured to compare the temperature differential to a threshold. Responsive to the temperature differential being less than the threshold, the controller is configured to calculate an adjusted setpoint for the flow control device as a function of both the temperature differential and the threshold and operate the flow control device to adjust the flow of the fluid through the heat exchanger in accordance with the adjusted setpoint.

Systems and methods for flow control in an HVAC system

A method for controlling flow in a heating, ventilation, and air conditioning (HVAC) system includes adjusting a setpoint associated with a valve based on a temperature change across a heating or cooling coil to reduce energy waste. The method includes receiving a first temperature measurement associated with an inlet of the coil, receiving a second temperature measurement associated with an outlet of the coil, calculating a difference between the first temperature measurement and the second temperature measurement, determining that the difference between the first temperature measurement and the second temperature measurement is below a threshold, and adjusting a setpoint associated with the valve. Additional control features may be provided to improve system behavior such as a pulse generation feature, a change-limiting feature, and a reevaluation feature.

A method for controlling flow in a heating, ventilation, and air conditioning (HVAC) system that imposes an upper limit on the flow of fluid through a heating or cooling coil. Imposing this limit on the flow rate ensures that a temperature change across the coil remains above a minimum threshold and can significantly reduce energy waste. The method includes receiving a first temperature measurement associated with an inlet of the coil, receiving a second temperature measurement associated with an outlet of the coil, and receiving a flow measurement associated with the valve, applying the first temperature measurement, the second temperature measurement, and the flow measurement as input to a model, determining a maximum flow rate that ensures that a difference between the first temperature measurement and the second temperature measurement is above a threshold using the model, and operating the valve in accordance with the maximum flow rate.

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Milwaukee, WI, United States of America

Rachel A Glanzer