Method, apparatus, and system for air-conditioning with dehumidification

Abstract

Embodiments comprise methods and arrangements for cooling and dehumidifying outgoing air. Embodiments may comprise a temperature sensor to couple with an air conditioning controller to cycle a fan for conditioned air to increase dehumidification of the conditioned air. Some embodiments comprise a temperature sensor coupled with the low pressure side return line and the fan to turn the fan on and off. In some embodiments, the temperature sensor may comprise logic to control a duty cycle of the fan. Some embodiments comprise a very low cost substitute for a continuously variable speed fan in the condenser unit to turn on the evaporator unit blower as needed and turn the blower off, e.g., roughly for half of every one minute, or turn the blower to low speed if the fan motor has a low speed wiring. Such arrangements may be installed as original equipment or as a retrofit.

1 . A method comprising:
 receiving, from an air conditioner controller, a signal to turn on a fan;   monitoring a temperature by a temperature sensor coupled with a low pressure side return line for a low-pressure coolant between an evaporative unit and a condenser unit; and   switching power applied to the fan to change the fan speed of the fan from a high speed fan state to a second fan state based upon the signal from the air conditioner controller and monitoring the temperature.   
     
     
         2 . The method of  claim 1 , further comprising determining a second fan state time, wherein determining the second fan state time comprises determining an amount of time to leave the fan in the second fan state to allow cooled coolant from the condenser unit resulting from the fan being in the second fan state to build up in the evaporative unit but not leave the evaporator coils while still cold. 
     
     
         3 . The method of  claim 2 , wherein determining an amount of time to leave the fan in the second fan state to allow cooled coolant from the condenser unit to enter the evaporative unit comprises estimating an amount of time to leave the fan off. 
     
     
         4 . The method of  claim 2 , wherein determining an amount of time to leave the fan in the second fan state to allow cooled coolant from the condenser unit to enter the evaporative unit comprises determining the amount of time based upon measuring an amount of time between changing the fan speed from the high speed fan state to the second fan state and receiving an indication of the change in the state of the fan speed via a subsequent temperature related to the low-pressure coolant in the low pressure side return line between the evaporative unit and the condenser unit. 
     
     
         5 . The method of  claim 4 , wherein the amount of time based upon measuring comprises setting an optimal second fan state time to between ten and fifteen seconds less than the amount of time to leave the fan off to allow cooled coolant from the condenser unit to pass completely through the evaporative unit still cold and partly still liquid. 
     
     
         6 . The method of  claim 4 , wherein determining the amount of time based upon measuring comprises setting an optimal second fan state time to between seventy percent and seventy-five percent of the amount of time to leave the fan off to allow cooled coolant from the condenser unit to pass completely through the evaporative unit still cold and partly still liquid. 
     
     
         7 . The method of  claim 1 , further comprising determining an optimal second fan state time by adjusting a second fan state time based upon temperature readings from a temperature sensor at the low pressure side return line and the timing of changes to temperature readings from the temperature sensor in relation to changes in the state of the fan speed of the fan. 
     
     
         8 . The method of  claim 7 , wherein determining the optimal second fan state time further comprises determining the optimal second fan state time to be a time period during which the temperature related to the coolant in the low pressure side return line drops by threshold temperature change. 
     
     
         9 . The method of  claim 7 , wherein determining the optimal second fan state time further comprises determining the optimal second fan state time to be a time period during which the temperature related to the coolant in the low pressure side return line resides within a predetermined temperature range. 
     
     
         10 . The method of  claim 7 , wherein determining the optimal second fan state time further comprises determining the optimal second fan state time to be less than the second fan state time the by a predetermined amount of time or a predetermined proportion of time. 
     
     
         11 . The method of  claim 7 , wherein determining the optimal second fan state time further comprises determining the optimal second fan state time by employing an algorithm to determine the optimal second fan state time based upon a balance between a temperature drop at the temperature sensor on the low pressure side return line and a timing of a drop in temperature at the temperature sensor on the low pressure side return line. 
     
     
         12 . The method of  claim 1 , wherein monitoring the temperature and switching the power applied comprises monitoring the temperature via a bi-metallic switch, wherein the bi-metallic switch switches between a first switch state and a second switch state in response to a threshold temperature, wherein switching between the first switch state and the second switch state in response to the threshold temperature changes the fan speed of the fan from the high speed fan state to the second fan state. 
     
     
         13 . The method of  claim 12 , further comprising applying heat to the bi-metallic switch in response to a change in state of the switch to reduce hysteresis lag time. 
     
     
         14 . The method of  claim 1 , wherein monitoring the temperature and switching the power applied to the fan comprises determining the temperature and switching the power applied to the fan via a thermometer element and a solid-state relay residing on a single integrated circuit of the module. 
     
     
         15 . An apparatus comprising:
 a housing adapted to couple with a low pressure side return line between an evaporative unit and a condenser unit, the housing comprising:
 a temperature sensor to determine a temperature related to a low-pressure coolant in the return line; and 
 a relay coupled with the temperature sensor to change a fan speed of a fan from a high speed fan state to a second fan state based upon a temperature indicated by the temperature sensor. 
   
     
     
         16 . The apparatus of  claim 15 , wherein the housing further comprises logic to couple with the temperature sensor to monitor the temperature related to the low-pressure coolant in a low pressure side return line between the evaporative unit and the condenser unit to determine when to change the fan speed of the fan from a high speed fan state to a second fan state based upon monitoring the temperature related to the low-pressure coolant in the return line. 
     
     
         17 . The apparatus of  claim 16 , wherein the logic comprises an output to output a signal to the relay to place the fan in a high speed fan state after the temperature falls below 40 degrees Fahrenheit. 
     
     
         18 . The apparatus of  claim 16 , wherein the logic comprises an output to output a signal to the relay to place the fan in a high speed fan state in response to a signal from an air conditioner controller indicating that a heater is on. 
     
     
         19 . The apparatus of  claim 15 , wherein the housing further comprises logic to couple with the temperature sensor to monitor the temperature related to the low-pressure coolant in a low pressure side return line between the evaporative unit and the condenser unit to minimize hysteresis involved with changing the fan speed of the fan from a high speed fan state to a second fan state based upon monitoring the temperature related to the low-pressure coolant in the return line. 
     
     
         20 . The apparatus of  claim 15 , wherein the housing further comprises logic to couple with the temperature sensor to monitor the temperature related to the low-pressure coolant in a low pressure side return line between the evaporative unit and the condenser unit to protect the fan from damage when repeatedly changing the fan speed of the fan between a high speed fan state and a second fan state. 
     
     
         21 . The apparatus of  claim 15 , wherein the housing further comprises logic to couple with the temperature sensor to monitor the temperature related to the low-pressure coolant in a low pressure side return line between the evaporative unit and the condenser unit to increase an efficiency of the fan when changing the fan speed of the fan between a high speed fan state and a second fan state by reducing a ratio between an amount of time that the fan is in the high speed fan state and an amount of heat transferred from air to the coolant. 
     
     
         22 . The apparatus of  claim 15 , wherein the housing further comprises logic to couple with the temperature sensor to monitor the temperature related to the low-pressure coolant in a low pressure side return line between the evaporative unit and the condenser unit to determine a duty cycle for the fan to change the fan speed of the fan from a high speed fan state to a second fan state based upon monitoring the temperature related to the low-pressure coolant in the return line. 
     
     
         23 . The apparatus of  claim 15 , wherein the temperature sensor comprises a bi-metallic switch to switch between a first switch state and a second switch state based upon the temperature related to the low-pressure coolant in the return line. 
     
     
         24 . The apparatus of  claim 15 , wherein the temperature sensor comprises at least one of a group of temperature sensing devices comprising a solid-state temperature sensor, a thermistor, a solid state switch to switch between one or more states based upon a temperature of the return line, and an integrated circuit with a switch to switch between an first switch state and a second switch state based upon the temperature of the return line. 
     
     
         25 . The apparatus of  claim 15 , wherein the logic comprises a timing circuit to learn an average second fan state time. 
     
     
         26 . The apparatus of  claim 25 , wherein the average second fan state time is an average fan-off time, the fan off time being the time period between which the fan is turned off and a coolant temperature in the return line is determined to be cooled by a threshold temperature change at the temperature sensor. 
     
     
         27 . The apparatus of  claim 25 , wherein the logic comprises logic to shorten the average second fan state time by switching the fan on about 10 seconds earlier than when the temperature sensor senses that the low-pressure coolant in the return line has reached a low threshold temperature as a result of placing the fan in the second fan state. 
     
     
         28 . The apparatus of  claim 25 , wherein the logic comprises logic to shorten the average second fan state time by switching the fan to the high speed state between 25% to 30% earlier than when the temperature sensor senses that the low-pressure coolant in the return line has reached a low threshold temperature as a result of placing the fan in the second fan state. 
     
     
         29 . An system comprising:
 an air-handling unit comprising at least one cabinet to receive an incoming air flow and to output a conditioned, outgoing air flow, the at least one cabinet comprising:
 an evaporative unit to receive coolant from a condenser unit, wherein the air-handling unit directs the incoming air flow through the evaporative unit; 
 a return line coupled with the evaporative unit to return low-pressure coolant to a compressor; 
 at least one fan to force air flow through the evaporative unit; and 
 a fan controller to adjust a speed of the fan to adjust the speed of the air flow through the evaporative unit; 
 a temperature sensor to couple with the return line between the evaporative unit and the condenser unit to determine a temperature related to the low-pressure coolant in the return line; and 
 a relay coupled with the temperature sensor to change the fan speed of the fan from a high speed fan state to a second fan state based upon the temperature related to the low-pressure coolant in the return line. 
   
     
     
         30 . The system of  claim 29 , further comprising logic to couple with the temperature sensor and the relay to monitor the temperature related to the low-pressure coolant in the return line between the evaporative unit and the condenser unit to determine when to change the fan speed of the fan from a high speed fan state to a second fan state based upon monitoring the temperature related to the low-pressure coolant in the return line. 
     
     
         31 . The system of  claim 30 , wherein the logic comprises a timing circuit to learn an average second fan state time, wherein the average second fan state time is an average fan-off time and wherein the logic shortens the average second fan state time by switching the fan on about 10 seconds earlier than when the temperature sensor senses that the low-pressure coolant in the return line has reached a low threshold temperature as a result of placing the fan in the second fan state. 
     
     
         32 . The system of  claim 30 , wherein the logic comprises a timing circuit to learn an average second fan state time and wherein the logic shortens the average second fan state time by switching the fan to the high speed state 25% earlier than when the temperature sensor senses that the low-pressure coolant in the return line has reached a low threshold temperature as a result of placing the fan in the second fan state. 
     
     
         33 . A method comprising:
 installing a temperature sensor on a return line between an evaporative unit and a condenser unit, wherein the return line returns a coolant exiting the evaporative unit to the condenser unit;   coupling a signal wire to the temperature sensor, the signal wire communicatively coupled with an air conditioner controller for transmitting a signal from the air conditioner controller to a fan controller to turn on the fan;   coupling a relay with the temperature sensor and the fan controller to switch between a first fan state and a second fan state based upon a temperature detected by the temperature sensor.   
     
     
         34 . The method of  claim 33 , wherein installing the temperature sensor comprises coupling the temperature sensor with the return line to measure the temperature of the return line. 
     
     
         35 . The method of  claim 33 , wherein installing the temperature sensor comprises coupling the temperature sensor with the return line via a heat sink.