High-low speed control algorithm for direct expansion air-conditioning systems for improved indoor humidity control and energy efficiency

Abstract

The present invention relates a method of dehumidifying an enclosed environment with a direct expansion air conditioning system, such direct expansion air conditioning system containing a two speed compressor and a two speed supply fan that allows the compressor and supply fan to run at high speeds in a steady-state or low speeds in a steady-state for better humidity control. Such a system allows for a more efficient, less costly system in comparison to single speed direct expansion air conditioner or direct expansion air conditioners with variable speed compressors and supply fans.

1 . A direct expansion air conditioner for controlling indoor air humidity in an environment, comprising
 a two speed compressor;   an expansion valve;   a condenser;   a two speed supply fan; and   a direct expansion evaporator containing direct expansion coils.   
   
   
       2 . The direct expansion air conditioner in  claim 1 , further comprising one or more variable frequency drivers. 
   
   
       3 . An air conditioning system for controlling the indoor humidity of an environment, comprising
 a refrigeration plant containing a two speed compressor, a direct expansion evaporator containing direct expansion coils, an expansion valve, a condenser, and a refrigerant;   an air distribution network containing ductwork, a two speed supply fan, an air filter, and a damper;   a control mechanism containing a microprocessor, user interface, power supply, communication means, memory, and algorithms;   one or more measuring devices;   and an enclosed environment.   
   
   
       4 . The air conditioning system in  claim 3 , wherein said two speed compressor is a rotor compressor. 
   
   
       5 . The air conditioning system in  claim 3 , wherein said algorithm on said control mechanism includes a comparison algorithm. 
   
   
       6 . The air conditioning system in  claim 3 , wherein said measuring devices includes an air dry-bulb, a wet dry-bulb, and a hygrometer. 
   
   
       7 . The air conditioning system in  claim 3 , wherein said enclosed environment is an apartment. 
   
   
       8 . A method of dehumidifying an enclosed environment with a direct expansion air conditioner, comprising,
 establishing one or more set points in said enclosed environment;   taking measurements from one or more measuring devices located within said enclosed environment;   storing said set points and said measurement on a memory of a control mechanism;   determining whether said measurement is above said set point in accordance with the following manner
 IF measurement is above said set point THEN run 
 a two speed compressor at high speed; and 
   maintaining said high speed of said two speed compressor in a steady-state.   
   
   
       9 . The method of  claim 8 , further comprising the step of determining whether said measurement is below said set point in accordance with the manner
 IF measurement is below said set point   THEN run a two speed compressor at low speed; and   maintaining said low speed of said two speed compressor in a steady-state.   
   
   
       10 . The method of  claim 9 , further comprising the step of determining whether said measurement is above said set point in accordance with the following manner
 IF measurement is above said set point, THEN run   a two speed supply fan at high speed;   
     and
 maintaining said high speed of said two speed supply fan in a steady-state. 
 
   
   
       11 . The method of  claim 10 , further comprising the step of determining whether said measurement is below said set point in accordance with the following manner
 IF measurement is below said set point, THEN run   a two speed supply fan at low speed;   
     and
 maintaining said low speed of said two speed supply fan in a steady-state. 
 
   
   
       12 . The method of  claim 9 , further comprising continuing collecting measurements from said measuring devices 
     and
 adjusting said compressor based on previous determining manner. 
 
   
   
       13 . The method of  claim 12 , further comprising the steps of continuing collecting measurements from said measuring devices, 
     and
 adjusting said supply fan based on previous determining manner. 
 
   
   
       14 . The method of  claim 8 , wherein establishing said set points includes establishing a desired humidity on a measuring device located within said environment. 
   
   
       15 . The method of  claim 8 , wherein establishing said set point includes establishing an air-dry temperature and an air-wet temperature on one or more measuring devices located within said environment. 
   
   
       16 . The method of dehumidifying in  claim 8 , wherein storing said set points and measurements occurs through communication means. 
   
   
       17 . The method of dehumidifying in  claim 8 , wherein determining whether said measurement is above said set point occurs via a comparison algorithm stored on a control mechanism. 
   
   
       18 . The method of dehumidifying in  claim 17 , wherein determining whether said measurement is above said set point occurs via said comparison algorithm allows for a deviation between said measurement and said set point from 0.1 to 0.5 points. 
   
   
       19 . The method of dehumidifying in  claim 8 , wherein maintaining said low speed of said two speed compressor means maintaining said speed at 50% of said high speed. 
   
   
       20 . The method of dehumidifying in  claim 10 , wherein maintaining said low speed of said two speed supply fan means maintaining said speed at 50% of said high speed.