Systems and methods for reheat control of an HVAC system
AssigneeJohnson Controls Tyco IP Holdings LLP
InventorsJohn T. Knight, Stephen B. Pickle, Norman J. Blanton, Kerry L Shumway
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Abstract
A heating, ventilation, and/or air conditioning (HVAC) unit includes a first sensor disposed adjacent to an inlet of an evaporator configured to receive an airflow. The HVAC unit includes a second sensor disposed adjacent to an outlet of a reheat coil positioned downstream of the evaporator and configured to expel the airflow. The HVAC unit also includes a controller configured to regulate operation of a modulating reheat valve to adjust flow of a working fluid in thermal communication with the airflow to control a difference between a measurement of the first sensor and a measurement of the second sensor.
Claims19
A heating, ventilation, and/or air conditioning (HVAC) system comprising a controller configured to:
- receive, from a first sensor, first feedback indicative of a first temperature of an air flow received by the HVAC system as return air;
- receive, from a second sensor, second feedback indicative of a second temperature of the air flow output by the HVAC system as supply air;
- and
- control a modulating reheat valve of the HVAC system to adjust flow of a working fluid to a reheat coil in thermal communication with the air flow, wherein, to control the modulating reheat valve, the controller is configured to:
- instruct the modulating reheat valve to increase a flow rate of the working fluid to the reheat coil in response to a first determination that the second temperature is below the first temperature by a non-zero threshold amount;
- or
- instruct the modulating reheat valve to decrease the flow rate of the working fluid to the reheat coil in response to a second determination that the second temperature is above the first temperature by the non-zero threshold amount;
- or
- both.
A heating, ventilation, and/or air conditioning (HVAC) unit, comprising:
- an enclosure defining an air flow path;
- an evaporator and a reheat coil disposed within the air flow path, wherein the evaporator and the reheat coil are each configured to receive a working fluid of a vapor compression system;
- a first sensor positioned upstream of the evaporator along the air flow path;
- a second sensor positioned downstream of the reheat coil along the air flow path;
- a modulating reheat valve configured to transition between a plurality of discrete positions, wherein the modulating reheat valve is configured to distribute the working fluid to the reheat coil and to a condenser of the HVAC unit in parallel in each discrete position of the plurality of discrete positions;
- and
- a controller configured to adjust the modulating reheat valve between the plurality of discrete positions to control a difference between a first measurement provided by the first sensor and a second measurement provided by the second sensor.
A control system of a heating, ventilation, and/or air conditioning (HVAC) system, wherein the control system comprises a controller configured to:
- receive, from a first sensor, first feedback indicative of a first temperature of return air received by the HVAC system;
- receive, from a second sensor, second feedback indicative of a second temperature of supply air discharged by the HVAC system;
- and
- instruct a modulating reheat valve to increase a flow rate of a working fluid to a reheat coil in fluid communication with the return air in response to a determination that the second temperature is below the first temperature by a non-zero threshold amount.
Dependencies are inferred from the claim text.