Heat exchange apparatus, system, and method

A controller for operating a heat exchange apparatus having a heat exchanger to receive a fluid, an airflow generator, a liquid distribution system comprising at least one of a pump and a valve, and a liquid absorbent material, the controller comprising:

• a memory storing instructions for operating the heat exchange apparatus;
• communication circuitry configured to communicate control signals to the heat exchange apparatus to operate the heat exchange apparatus;
• a processor operably connected to the memory and the communication circuitry, the processor configured to:
• determine, based at least in part upon a setpoint temperature for the fluid, to change the mode of operation of the heat exchange apparatus from a dry mode wherein the liquid distribution system is inhibited from distributing liquid onto the liquid absorbent material to a wet mode wherein the liquid distribution system distributes liquid onto the liquid absorbent material;
• and
• in response to the determination to change the mode of operation from the dry mode to the wet mode:
• determine a limit for an operating parameter of at least one of the liquid distribution system and the airflow generator during operation in the wet mode;
• cause the liquid distribution system to distribute liquid onto the liquid absorbent material including operating the heat exchange apparatus based at least in part upon the limit for the operating parameter for a transition time period starting when the controller determines to change from the dry mode to the wet mode to inhibit drift of liquid from the liquid absorbent material toward the heat exchanger as the liquid saturates the liquid absorbent material at a beginning of the wet mode;
• and
• upon expiration of the transition time period that started when the controller determines to switch from the dry mode to the wet mode, operate the heat exchange apparatus based at least in part upon the operating parameter to permit the heat exchange apparatus to operate at full capacity once the liquid has saturated the liquid absorbent material.

A method for operating a heat exchange apparatus having a heat exchanger to receive a fluid, an airflow generator, a liquid distribution system comprising at least one of a pump and a valve, and a liquid absorbent material, the method comprising:

• at one or more processors:
• determining, based at least in part upon a setpoint temperature for the fluid, to change a mode of operation of the heat exchange apparatus from a dry mode wherein a liquid distribution system of the heat exchange apparatus is inhibited from distributing liquid onto the liquid absorbent material of the heat exchange apparatus to a wet mode wherein the liquid distribution system distributes liquid onto the liquid absorbent material;
• and
• in response to determining to change the mode of operation from the dry mode to the wet mode:
• determining a limit for an operating parameter of at least one of the liquid distribution system and the airflow generator during operation in the wet mode;
• cause the liquid distribution system to distribute liquid onto the liquid absorbent material including operating the at least one of the liquid distribution system and the airflow generator of the heat exchange apparatus based at least in part upon the limit for the operating parameter for a transition time period starting when the one or more processors determine to switch from the dry mode to the wet mode to inhibit drift of liquid from the liquid absorbent material toward the heat exchanger as the liquid saturates the liquid absorbent material at a beginning of the wet mode;
• and
• upon expiration of the transition time period that started when the one or more processors determine to switch from the dry mode to the wet mode, operate the at least one of the liquid distribution system and the airflow generator based at least in part upon the operating parameter to permit the heat exchange apparatus to operate at full capacity once the liquid has saturated the liquid absorbent material.