Detecting and correcting enthalpy wheel failure modes

• US 10,197,344 B2
• Filed: 06/24/2016
• Issued: 02/05/2019
• Est. Priority Date: 10/06/2011
• Status: Active Grant

• Current Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Original Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Inventors: McKie, Justin, Perez, Eric, Thomas, Greg, Schneider, Steve
• Primary Examiner(s): Masinick, Michael D
• Application Number:
  US15/192,608
• Publication Number:
  US 20160305723A1
• Time in Patent Office: 956 Days
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/32 Responding to malfunctions or emergencies
• CPC Class Codes: F24F 11/38 Failure diagnosis
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 11/64 using pre-stored data
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 11/81 by controlling the air supply to heat-exchangers or bypass channels
• CPC Class Codes: F24F 12/006 using an air-to-air heat exchanger F24F12/002 takes precedence
• CPC Class Codes: F24F 2110/40 Pressure, e.g. wind pressure
• CPC Class Codes: F24F 2140/00 Control inputs relating to system states
• CPC Class Codes: F24F 2203/10 Rotary wheel
• CPC Class Codes: F24F 2203/104 Heat exchanger wheel
• CPC Class Codes: F28D 19/041 with axial flow through the intermediate heat-transfer medium
• CPC Class Codes: F28F 27/006 specially adapted for regenerative heat-exchange apparatus
• CPC Class Codes: Y02B 30/56 Heat recovery units
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating
• CPC Class Codes: Y10T 29/4935 Heat exchanger or boiler making

Abstract

A heating ventilation and cooling system includes an energy recovery ventilator (ERV). The ERV is configured to produce an inlet airstream and an exhaust airstream. An enthalpy wheel within the energy recovery ventilator is operable to transport heat between the inlet and exhaust airstreams. A pressure transducer is configured to determine a backpressure across the enthalpy wheel. A controller is configured to determine, in response to the backpressure, an operational characteristic of the enthalpy wheel.

Claims

1. A method for heating, ventilating, and cooling comprising:

determining an outside air temperature;

recording a rate of change of pressure in a region of an energy recovery ventilator, wherein the energy recovery ventilator is operable to produce an inlet airstream and an exhaust airstream;

determining that an enthalpy wheel positioned within the energy recovery ventilator and operable to transport heat between the inlet and exhaust airstreams is in a frosted condition if the rate of change of air pressure within the energy recovery ventilator is greater than a stored normal rate of change of air pressure and the outside air temperature is below a stored temperature value;

determining that the enthalpy wheel is in a disabled condition if the rate of change of the air pressure within the energy recovery ventilator is greater than the stored normal rate of change of air pressure and the outside air temperature is higher than the stored temperature value; and

setting the operating speed of an exhaust blower to a predetermined speed based on the determined condition of the enthalpy wheel.

2. The method as recited in claim 1, wherein the energy recovery ventilator is operable to produce the inlet airstream by drawing outside air into the energy recovery ventilator.

3. The method as recited in claim 1, further comprising:

measuring air pressure within at least a region of the energy recovery ventilator;

determining a pressure differential across the enthalpy wheel based, at least in part, upon the measured air pressure; and

determining an airflow rate through the enthalpy wheel based, at least in part, upon the pressure differential.

4. The method as recited in claim 1, wherein the enthalpy wheel is one of two enthalpy wheels within the energy recovery ventilator, and the method further comprises determining that one of the enthalpy wheels is disabled.

5. The method as recited in claim 1, further comprising directing the inlet airstream into a conditioning unit coupled to the energy recovery ventilator.

6. The method as recited in claim 4, further comprising reducing airflow of the inlet and exhaust airstreams in the event that one of the enthalpy wheels is inoperable.

7. The method as recited in claim 4, further comprising communicating an alarm condition in the event that one of the enthalpy wheels is inoperable.