Method and apparatus for re-heat dehumidification utilizing a variable speed compressor system

• US 10,386,089 B2
• Filed: 02/16/2016
• Issued: 08/20/2019
• Est. Priority Date: 11/30/2015
• Status: Active Grant

• Current Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Original Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Inventors: Goel, Rakesh, Phillips, Derek
• Primary Examiner(s): Bauer, Cassey D
• Assistant Examiner(s): Hopkins, Jenna M
• Application Number:
  US15/044,243
• Publication Number:
  US 20170234564A1
• Time in Patent Office: 1,281 Days
• Field of Search: None
• CPC Class Codes: F24F 1/0003 characterised by a split arrangement, wherein parts of the air-conditioning system, e.g. evaporator and condenser, are in separately located units
• 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 11/52 Indication arrangements, e.g. displays
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 11/86 by controlling compressors within refrigeration or heat pump circuits
• CPC Class Codes: F24F 11/871 by controlling outdoor fans
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2110/12 of the outside air
• CPC Class Codes: F24F 2110/20 Humidity
• CPC Class Codes: F24F 2120/20 Feedback from users
• CPC Class Codes: F24F 2140/20 Heat-exchange fluid temperature
• CPC Class Codes: F24F 2221/16 mounted on the roof
• CPC Class Codes: F24F 3/044 Systems in which all treatment is given in the central station, i.e. all-air systems
• CPC Class Codes: F24F 3/14 by humidification; by dehumidification
• CPC Class Codes: F24F 3/1405 in which the humidity of the air is exclusively affected by contact with the evaporator of a closed-circuit cooling system or heat pump circuit
• CPC Class Codes: F25B 2600/0253 with variable speed
• CPC Class Codes: F25B 2600/11 Fan speed control
• CPC Class Codes: F25B 2700/02 Humidity
• CPC Class Codes: F25B 2700/21171 of the fluid cooled by the evaporator
• CPC Class Codes: F25B 2700/21174 : of the refrigerant at the inlet of the evaporator
• CPC Class Codes: F25B 39/028 : having distributing means
• CPC Class Codes: F25B 41/42 : Arrangements for diverging or converging flows, e.g. branch lines or junctions
• CPC Class Codes: F25B 49/02 : for compression type machines, plants or systems
• CPC Class Codes: Y02B 30/70 : Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A heating, ventilation, and air conditioning (HVAC) system for regulating humidity of an enclosed space. The HVAC system includes an evaporator coil. A metering device is fluidly coupled to the evaporator coil. A variable-speed compressor is fluidly coupled to the condenser coil and the evaporator coil and a controller is operatively coupled to the variable-speed compressor. A humidity sensor is operatively coupled to the controller and exposed to the enclosed space. Responsive to a determination that the relative humidity of the enclosed space exceeds the maximum humidity threshold, the controller adjusts a speed of the variable-speed compressor to increase latent capacity of the HVAC system. Responsive to a determination that the relative humidity of the enclosed space falls below the minimum humidity threshold, the controller adjusts a speed of the variable-speed compressor to decrease latent capacity of the HVAC system.

Claims

1. A heating, ventilation, and air conditioning (HVAC) system for regulating humidity of an enclosed space, the HVAC system comprising:

an evaporator coil;

a thermostatic expansion valve fluidly coupled to the evaporator coil via a distributor line;

a variable-speed circulation fan for circulating air around the evaporator coil;

a condenser coil fluidly coupled to the thermostatic expansion valve;

a variable-speed compressor fluidly coupled to the condenser coil and the evaporator coil;

a controller operatively coupled to the variable-speed compressor;

a three-way valve fluidly coupled to the condenser coil;

a re-heat coil fluidly coupled to the three-way valve, the re-heat coil being positioned downwind of the evaporator coil;

a humidity sensor operatively coupled to the controller and exposed to the enclosed space, wherein the humidity sensor is configured to measure a relative humidity of the enclosed space and detect if the relative humidity of the enclosed space exceeds a maximum humidity threshold or falls below a minimum humidity threshold;

a variable-speed condenser fan operatively coupled to the controller for circulating air around the condenser coil;

a first temperature sensor disposed in a return air duct, the first temperature sensor being operatively coupled to the controller;

a second temperature sensor disposed in a supply air duct, the second temperature sensor being operatively coupled to the controller, the first temperature sensor and the second temperature sensor measuring a temperature difference between the return air duct and the supply air duct;

wherein the controller is configured to;

responsive to a determination that the relative humidity of the enclosed space exceeds the maximum humidity threshold, adjust a speed of the variable-speed compressor to increase latent capacity of the HVAC system;

responsive to a determination that the relative humidity of the enclosed space falls below the minimum humidity threshold, adjust a speed of the variable-speed compressor to decrease latent capacity of the HVAC system;

determine if at least one of over-cooling and over-heating of air in the enclosed space occurs based on a change in the temperature difference;

responsive to a positive determination of over-cooling of air in the enclosed space, reduce a speed of the variable-speed condenser fan; and

responsive to a positive determination of over-heating of air in the enclosed space, increase the speed of the variable-speed condenser fan.

2. The HVAC system of claim 1, wherein the HVAC system is a package HVAC system.

3. The HVAC system of claim 1, wherein the HVAC system is a split HVAC system.

4. The HVAC system of claim 1, wherein the humidity sensor measures the relative humidity of the enclosed space at periodic time intervals.

5. The HVAC system of claim 4, wherein the periodic time intervals comprise five seconds.

6. The HVAC system of claim 1, comprising:

the variable-speed circulation fan for circulating air around the evaporator coil and operatively coupled to the controller;

a distributor line temperature sensor thermally exposed to the distributor line and operatively coupled to the controller; and

wherein the controller adjusts a speed of the variable-speed circulation fan to increase latent capacity of the HVAC system responsive to a determination that a temperature of fluid in the distributor line exceeds an optimal distributor line temperature.

7. The HVAC system of claim 6, wherein the speed of the variable-speed compressor is adjusted prior to adjusting the speed of the variable-speed circulation fan.

8. The HVAC system of claim 1, wherein the speed of the variable-speed compressor is adjusted prior to adjusting the speed of the variable-speed condenser fan.

9. The HVAC system of claim 1, wherein the controller is configured to increase a speed of the variable-speed compressor responsive to a determination that the relative humidity of the enclosed space exceeds the maximum humidity threshold.

10. A heating, ventilation, and air conditioning (HVAC) system for regulating humidity of an enclosed space, the HVAC system comprising:

an evaporator coil;

a thermostatic expansion valve fluidly coupled to the evaporator coil via a distributor line;

a variable-speed circulation fan for circulating air around the evaporator coil;

a condenser coil fluidly coupled to the thermostatic expansion valve;

a variable-speed compressor fluidly coupled to the condenser coil and the evaporator coil;

a controller operatively coupled to the variable-speed compressor;

a three-way valve fluidly coupled to the condenser coil;

a re-heat coil fluidly coupled to the three-way valve, the re-heat coil being positioned downwind of the evaporator coil;

a first temperature sensor thermally exposed to the distributor line and operatively coupled to the controller;

a humidity sensor operatively coupled to the controller and exposed to the enclosed space wherein the humidity sensor is configured to measure a relative humidity of the enclosed space and detect if the relative humidity of the enclosed space exceeds a maximum humidity threshold or falls below a minimum humidity threshold;

wherein the controller is configured to;

responsive to a determination that the relative humidity of the enclosed space exceeds the maximum humidity threshold, adjust a speed of the variable-speed compressor to increase latent capacity of the HVAC system;

responsive to a determination that the relative humidity of the enclosed space falls below the minimum humidity threshold, adjust a speed of the variable-speed compressor to decrease latent capacity of the HVAC system;

responsive to a determination that a temperature of fluid in the distributor line exceeds an optimal distributor line temperature, reduce a speed of the variable-speed circulation fan to increase latent capacity of the HVAC system and lower a temperature of the evaporator coil;

determine if at least one of over-cooling and over-heating of air in the enclosed space occurs based on a change in an air temperature difference between a return air duct and a supply air duct over time;

responsive to a positive determination of over-cooling of air in the enclosed space, reduce a speed of a variable-speed condenser fan; and

responsive to a positive determination of over-heating of air in the enclosed space, increase the speed of the variable-speed condenser fan.