Selective temperature control system
First Claim
1. A temperature control system for a space cooling device having an evaporator, a variable speed evaporator fan and a compressor, comprising:
- an ambient thermistor having a resistance variable in accordance with the temperature of a space;
conversion means coupled to said ambient thermistor for converting said thermistor resistance into a digital number proportional to said space temperature;
a memory for storing a plurality of digital numbers representing set point temperatures;
set point selection means coupled to said memory for retrieving from said memory one of said digital set point numbers;
difference means coupled to said conversion means and said set point selection means for determining the difference between said digital space temperature number and said selected digital set point number;
control means coupled to said difference means for adjusting the speed of said evaporator fan and the energization of said compressor; and
operation mode selection means coupled to the control means for selecting at least one of a plurality of operation modes including a first mode in which the evaporator fan speed and the compressor energization are controlled according to the magnitude of said difference and a second mode in which only the compressor energization is controlled according to the magnitude of said difference.
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Accused Products
Abstract
A room air conditioner includes a variable speed eevaporator fan and a compressor selectively energized by a temperature control system. An ambient temperature sensor monitors the temperature of the room and an evaporator temperature sensor monitors the temperature of the evaporator. In an automatic mode of operation, the evaporator fan speed and compressor energization depend upon the difference between the ambient temperature and a set point temperature as determined by the position of a slide switch with multiple contacts each of which correspond to a stored set point value. The ambient and evaporator temperatures are determined by a linearization computation which utilizes a capacitor sequentially charged through the reference resistor and the ambient thermistor and the evaporator thermistor. The compressor is cycled off when the evaporator temperature falls below a certain value, and the compressor is held off for a fixed period of time after it has been de-energized to prevent short cycling or lockup.
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Citations
42 Claims
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1. A temperature control system for a space cooling device having an evaporator, a variable speed evaporator fan and a compressor, comprising:
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an ambient thermistor having a resistance variable in accordance with the temperature of a space; conversion means coupled to said ambient thermistor for converting said thermistor resistance into a digital number proportional to said space temperature; a memory for storing a plurality of digital numbers representing set point temperatures; set point selection means coupled to said memory for retrieving from said memory one of said digital set point numbers; difference means coupled to said conversion means and said set point selection means for determining the difference between said digital space temperature number and said selected digital set point number; control means coupled to said difference means for adjusting the speed of said evaporator fan and the energization of said compressor; and operation mode selection means coupled to the control means for selecting at least one of a plurality of operation modes including a first mode in which the evaporator fan speed and the compressor energization are controlled according to the magnitude of said difference and a second mode in which only the compressor energization is controlled according to the magnitude of said difference.
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2. A temperature control system for a space cooling device having an evaporator, a variable speed evaporator fan and a compressor, comprising:
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an ambient thermistor having a resistance variable in accordance with the temperature of a space; conversion means coupled to said ambient thermistor for converting said thermistor resistance into a digital number proportional to said space temperature including a capacitor, a reference resistor connected in series with said capacitor, and charging means for sequentially charging said capacitor through said reference resistance and said ambient thermistor; a memory for storing a plurality of digital numbers representing set point temperatures; selection means coupled to said memory for retrieving from said memory one of said digital set point numbers; difference means coupled to said conversion means and said selection means for determining the difference between said digital space temperature number and said selected digital set point number; and control means coupled to said difference means for adjusting the speed of said evaporator fan and the energization of said compressor according to the magnitude of said difference. - View Dependent Claims (3, 4)
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5. A temperature control system for a space cooling device having an evaporator, a variable speed evaporator fan and a compressor, comprising:
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an ambient thermistor having a resistance variable in accordance with the temperature of a space; conversion means coupled to said ambient thermistor for converting said thermistor resistance into a digital number proportional to said space temperature; a memory for storing a plurality of digital numbers representing set point temperatures; selection means coupled to said memory for retrieving from said memory one of said digital set point numbers including a switch having a plurality of contacts and a wiper connected to an output for connecting one of said contacts to said output; difference means coupled to said conversion means and said selection means for determining the difference between said digital space temperature number and said selected digital set point number; and control means coupled to said difference means for adjusting the speed of said evaporator fan and the energization of said compressor according to the magnitude of said difference. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A temperature control system for a space cooling device having an evaporator, a variable speed evaporator fan, and a compressor, comprising:
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an ambient temperature sensor having a resistance dependent on the temperature of a space; an evaporator temperature sensor having a resistance dependent on the temperature of said evaporator; conversion means coupled to the ambient and evaporator temperature sensors for converting the resistances thereof into digital numbers representing said space temperature and said evaporator temperature respectively; selection means for selecting one of a plurality of digital temperature set points; control means coupled to said conversion means and said selection means for adjusting the speed of said evaporator fan and the energization of said compressor according to the difference between said digital number representing the temperature of said space and said selected digital temperature set point; and de-energization means coupled to said conversion means for turning the compressor off when said digital number representing the evaporator temperature falls below a predetermined value. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 42)
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26. A temperature control system for a space cooling device having an evaporator, a variable speed evaporator fan and a compressor, comprising:
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an ambient temperature sensor having a resistance responsive to the temperature of said space; a memory for storing a plurality of digital set points; selection means coupled to said memory for retrieving one of said digital set points from said memory; conversion means coupled to said ambient temperature sensor for converting said resistance into a digital number proportional to said space temperature; differences means coupled to said selection means and said conversion means for determining the difference between said digital number and said digital set point number; search means coupled to said difference means for selecting from a plurality of intervals the one interval within which said difference falls; and control means for adjusting said fan speed and said compressor energization according to the selected interval. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A temperature control system for a space cooling device having an evaporator, a variable speed evaporator fan, a compressor and control means including a microcomputer, comprising:
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an ambient thermistor having a resistance variable in accordance with the temperature of a space; conversion means coupled to said ambient thermistor and said microcomputer for converting said thermistor resistance into a digital number proportional to said space temperature; a memory in said microcomputer for storing a plurality of digital numbers representing set point temperatures; selection means coupled to said memory for retrieving from said memory one of said digital set point numbers; and means coupled to said conversion means and said selection means for determining in said microcomputer the difference between said digital space temperature number and said selected digital set point number; and operation mode selection means for selecting at least one of a plurality of operation modes including a first mode in which the speed of said evaporator fan and the energization of said compressor are adjusted according to the magnitude of said difference and a second mode in which only the energization of said compressor is adjusted according to the magnitude of said difference while said evaporator fan is operated at a fixed speed.
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Specification