EP0072855A1 - Temperature control system with programmed dead-band features - Google Patents

Abstract

Methods, apparatus (11) and apparatuses (11) for controlling and measuring the energy-saving humidity temperature, effectively operating in response to received signals from occupants (60) and responses dynamics of a building (16) and its heating, ventilation and air conditioning system (12, 13). The methods, apparatus and system of the invention use thermostats (21) equipped with a dimming device to save energy; thermostats only require a reset to a neutral / comfort setting point, this setting being effected using a push button or a touch plate (110). The system is preprogrammed and adjusted to maintain the comfort of the occupants (60) although the temperature in the building (16) varies, this by controlling the rate of change so that the changes are gradual and do not occur. not notice.

Description

TEMPERATURE CONTROL SYSTEM WITH PROGRAMMED DΞAD-- BAND DRIFT FEATURES

Technical Field

Temperature and humidity sensing apparatuses systems and control processes which modulate air heating and cooling apparatus in environmental control systems. Background Art

The conventional residential thermostat with its on- off-auto, heat-cool sub-base is too complex for most occu¬ pants to operate efficiently, and some of the more recent energy-conserving thermostats which require instruction booklets are even more complicated to operate, and do not provide a simple solution to energy conservation.

The Emergency Building Temperature Restrictions were promulgated July 5, 1979, under the U.S. Department of Ener- gy, 10 CFR Part 490. These restrictions made it prohibitive in commercial and public buildings for an operator to set the thermostats so that energy is consumed to raise the room dry-bulb temperature above 65 deg F. {18 deg C.) or to set the thermostats so that ener-gy is-consumed to lower the room dry-bulb temperature below 78 deg F. (26 deg C) . For many buildings it was impractical to comply with the restriction by simple adjustment of the existing thermostats. There was also considerable reluctance to replace the thermostats due to the guaranteed discomfort as well as cost. Disclosure of the Invention

Means and sensitive to air temperature (17 and 18) and humidity (19) in a room of a dwelling (16) are connected through a measuring means (21) having an output (208) pro¬ portional to such temperature and humidity to a control cir- cuit (23) . The control circuit (23) is connected to and di- rects heating and cooling units (12 and 13) within the dwelling (16). The program control circuit (23) provides programs of progressively changing signals to progressively change the effective temperature in the dwelling. Industrial Applicability

The system is pre-programmed to permit the space tem¬ perature to drift at a controlled rate within a pre-selected dead-band range at a rate of 1 degree Fahrenheit per hour continuously or stepwise. The system saves energy by per¬ mitting space temperature to always drift in the energy conserving direction (i.e. up or down) and when actuated brings the space (16) under ideal control before drifting at an unnoticeable rate, as in FIGS. VI and VII, in the energy- conserving direction. Energy abusive over-adjustment does not occur as with other thermostats. Such controlled drift provides greater comfort than thermostats which have a broad dead-band wherein room temperatures within the dwelling can ^* rise or fall rapidly and energy is saved while making com¬ fort available at all times to a human occupant (60) within such room or space within the dwelling because the rate of change of the drift of temperature (1 deg. F./hr.) is not noticeable to a -human occupant. Brief Description of the Drawings

FIGURE I is an overall view ^'of ^"the principal assemblies within the system 10 according to this invention.

FIGURE II is a detailed showing of the terminal por¬ tions of the logic system 27 of cycle selector assembly 22 and the resistor bank subassembly 28 of the overall range control assembly 23 in zone IIA of FIG. I.

FIGURE III is a diagrammatic showing of electrical com¬ ponent block connections in zone IIIA of FIG. I.

FIGURE IV is an electrical diagram of parts and con- nections of apparatus in zone IVA of FIG. I.

FIGURE V is an equivalent circuit diagram of the inte¬ grated circuit 200 in zone VA of FIGS. Ill and IV.

FIGURE VI shows the temperature changes and stages in a heating cycle control operation of the system of FIG. I ac*- cording to one embodiment of process of this invention.

FIGURE VII shows the temperature changes and stages in a cooling cycle control operation of the system of FIG. I according to another embodiment of process of this inven¬ tion. FIGURE VIII diagram atically shows parts and connec¬ tions within one resistor bank unit assembly, 91.

FIGURE IX shows principal parts of a pulse drive mech¬ anism 24 within resistor control unit 29. FIGURE X shows circuit connections and parts of the unijunction timer 111 of FIG. IX.

FIGURE XI is a diagrammatic showing of 'an electrical circuit and mechanical parts within a humidity sensor and control unit 160 of which parts are shown in FIGS. I, III and IV.

FIGURE XII shows principal parts of a motor drive asse¬ mbly mechanism 140 within resistor control unit 29.

FIGURE XIII diagrammatically shows the graphical rela- tionships of temperature, humidity and electrical resistance within a control circuit as in FIGS. Ill and IV using a thermistor and a humidity transducer each having a positive temperature coefficient.

FIGURE XIV shows the relation of components shown in FIGS. II and XV.

FIGURE XV shows an intermediate portion of the logic system circuit 27 of cycle selec^'tor assembly 22 and resis¬ tor bank assembly 28 of range control assembly 23.

FIGURE XVI diagrammatically shows the relations of temperature and electrical resistance of a thermistor with a negative temperature coefficient used inthe circuits of FIGS. Ill and IV.

FIGURE XVII diagrammatically shows the relations of humidity and electrical resistance of a humidity transducer with a negative temperature coefficient used in the circuits of FIGS... Ill and IV.

Modes of Carrying Out the Invention The system 10 of this invention comprises a program control apparatus 11, a house heating unit 12, a house cool¬ ing unit 13, a heating unit control relay 14 and a cooling unit control relay 15. The heating unit and cooling unit are operatively connected to a building or dwelling 16. The program control apparatus 11 provides for control of the heating unit 12 and cooling unit 13 to provide temperature change of one degree Fahrenheit per hour on controlled drift.

The program control apparatus 11 comprises, in opera- tive combination, a power source 20, a cycle selector assem¬ bly 22, and a temperature control assembly 23.

The cycle selector assembly 22 comprises, in operative combination, a temperature sensor unit 21, a frequency sen- sitive selector circuit assembly 26 and a logic unit assem¬ bly 27, all connected together as in FIGS. II, XIV and XV and below describefd. Temperature sensor unit 21 comprises a 555 integrated circuit 200, connected to other components in an electrical circuit as shown in FIGS. -IV and V. _* Temperature sensor elements 17 and 18 for units 30 and 21 respectively and a humidity sensor 1-9 are located in wall mounted housings therefor in the dwelling 16.

Heating- and cooling control switches 40 and 50 are also located in wall mounted housings 340 and 350 respectively in the dwelling 16. The selector circuit assembly 26 comprises a series_vof generally like frequency sensitive electrical units as 31-37, each sensitive and res¬ ponsive to one principal or particular frequency of the out¬ put of temperature sensor unit 21". The temperature control assembly 23 comprises a resis¬ tor bank assembly 28, a resistor control unit 29, and a tem¬ perature range controller unit 30. The- temperature range controller unit 30 is a 555 timer as 200 connected with other electrical components in an electrical circuit as shown in FIG. III. The resistor bank assembly or group 28 comprises a series of like connected and arranged and actua¬ ted resistor unit assemblies as 91-99 shown in FIGS. II, XIV and XV.

The program control apparatus 11 comprises a frequency sensor and selector unit as one of 31-39 of assembly 22 and a resistor unit as one of 91-99 of assembly 23 for each de¬ gree Fahrenheit of the range as 65 deg F to 85 deg F shown in FIGS. VI and VII, of operation of the system 11. The terminal apparatus portions shown as XIV B and XIV C in FIGS. II and XIV and comprising sensor units as 31-34 and resistor units 91-94 and sensor units 37-39 and resistor units 97-99 and circuit elements connected thereto as shown in FIG. II are representative of the terminal portions of

" the circuity of selector assembly 22 and control assembly 23. Additional intermediate units as sensor units 35 and 36 and resistor units as 95 and 96 and circuitry therebetween are provided between and connected to units 34 and 94 and 37 and 97 respectively as shown in FIG. XV; the number of such additional intermediate units is greater -than those shown in FIG. XV as representative of such additional intermediate units in order to provide one sensor unit as 33 and one re¬ sistor unit as 93 for each degree Fahrenheit of the range of operation of the program control apparatus 11.

Components and connections of one resistor unit assem¬ bly, 91, are shown in. IG. VIII. Each of the resistor unit assemblies as 91-99 has different resistance values of its components, as 121-124 of unit 91, than other assemblies in the resistor bank assembly or group 28.

The resistor control unit 29, in one embodiment of ap- paratus, 140, shown in FIG. XII ^'comprises a return unit 150 and a 12-hour motor, as 141, whose output completes one 360 degree complete revolution in twelve hours, and which is . coupled with gearing 142 to provide continuous change of resistance values between the resistor bank terminal wires as 151, 152 and 153, which wires are connected to the overall resistance portions as 128 and 129 on each side of the wiper arms as 131 of the resistor units as 91-913. Wires 151, 152 and 153 are connected at the input of^* the temperature range controller unit 30 for continuous operation as in FIG. VI. Reversing unit 150 is connected ^'to relay- 109 and power source 20 and is actuated automatically upon cessation of operation of the cycle of operation of motor 141 to return to control shaft 116 of the resistor assembly 28 to its start position.

In another embodiment of resistor control unit appara¬ tus, shown in FIG. IX, the resistor control unit 29 compri¬ ses a return unit 150, and a pulse drive assembly 24 which provides timed and stepped increments of resistance value change in the value of resistors of the resistor bank units connected at the input of the temperature range controller unit 30 for stepped operation as illustrated in FIG. VII.

In general, the program control apparatus 11 is direc¬ ted to provide programs wherein the temperature may con- trollably drift or change within the dwelling, as 16, by one degree Fahrenheit (0.6 deg. C.) per hour. The direc- tion of the drift will generally be in the direction from which the control signal comes but will always be in the energy conserving direction which tends to eliminate the im¬ mediate call for heating or cooling energy input. Logic Unit Assembly 27 The logic unit assembly 27 comprises an electrical cir¬ cuit with a heating control switch 40, and a cooling control switch 50 located in housings therefor in the dwelling 16 and AND circuits as 41-48, 51-57 and 71-77 and inhibiting circuits as 61-67 and 81-87. The circuits of assembly 27 provide that with the tem¬ perature sensor 21 activated at a given temperature, e.g. 74 degrees F., and only one of frequency sensor and^* selector circuit units as 31-39 activated only one of the relays as one of 101-109 respectively is actuated to control the switch arms therefor and respectively connect one of the resistor bank unit assemblies as one of 91-99 via wires 151, 152 and 153 to the temperature range control unit 30. When, however, two frequency sensor and selector circuit units as 32 and 33 are concurrently actuated because of overlap in range of temperature sensed and reacted to by both ^'such neighboring sensor and related circuit units (as 32 and 33) then selection of only one or another resistor unit assembly of two adjacent- resistor unit assemblies as 92 and 93 is automatically effected by the logic circuit 27 as hereinbe- low described. The outputs of adjacent or neighboring frequency sensor and selector circuits units in assembly 27, as for example units 32 and 33, are connected to a common AND circuit, as 42, and that AND circuit (42) is connected to other AND circuits 52 and 71. Each of the AND circuits 51-57 is connected to the heating control switch 40 and each of the AND circuits 71-77 is connected to the cooling control switch 50. .With the heating control switch 40 oper¬ ating or in closed circuit condition and switch 50 open, ac- tuation of two neighboring units as 32 and 33 serves to ac¬ tuate the AND circuits 42 and 52; such connection also inhibits, through the inhibitor switch 62, actuation of one normally open relay 103 and provides for connection of the normally open relay 102 and resistors of resistor bank unit assembly 92 so that the cycle of operation of controller 30 with the resistors of the resistor bank unit assembly 92 of resistor bank assembly 28 is initiated. Similarly on the heating cycle (switch 40 closed and switch 50 automatically concurrently open) on concurrent actuation of the frequency sensor and selector circuit units 33 and .34, the AND cir¬ cuit 43 is actuated as well as the AND circuit 53 to inhibit, through inhibiting switch.63, the actuation of re¬ lay 104 for the resistor bank unit assembly 94 while the normally open relay 103 for connection of the resistors of resistor, bank unit assembly 93 is then actuated arid the^"re¬ sistors of that unit assembly 93 are connected to the range controller unit 30.

With the cooling control switch 50 operating or in closed circuit condition and heating control switch 40 auto¬ matically open, actuation of units .32 and 33 serves to actu¬ ate the AND circuits 42 and 71; such connections also inhi¬ bits, through the inhibitor switch 81, actuation of the re¬ lay 102 and provide for connection of the relay 103 and the resistors of resistor bank unit assembly 93 so that the cycle of operation of range controller unit 30 with the resistors of the resistor bank unit assembly 93 of resistor bank 28 is initiated. Similarly on the cooling cycle (switch 50 closed and switch 40 automatically concurrently open) on concurrent actuation of the selector units 33 and 34 the AND circuit 43 is actuated as well as the AND circuit 72 to inhibit, through inhibiting switch 82, the actuation of relay 103 for the resistor unit 93 while the normally open relay 104 for the resistors of resistor unit 94 is then actuated and the resistors of resistor unit 94 are con¬ nected to range control unit 30.

The particular values of resistances in the resistor bank assembly 28 so connected to unit 30 provide the ini- tial temperature range at the boundaries of which the con¬ troller unit 30 provides for turning on and off the heating unit relay 14 or turning off and on the cooling unit relay 15 to maintain the temperature in the dwelling unit 16 with- in predetermined ranges of temperature. The initial rela¬ tive value of the resistances as 121-126 is determined by the initial position of each wiper arm as 131 held on the wiper arm drive shaft 116 for unit 91 (and by wiper arm as 132 for resistor unit 92) for a first value of resistance distribution and a total resistance value 128 on one side of each wiper arm as 131 and another resistance value as 129 on the other side of each such wiper arm as 131.

Each wiper arm as 131 and 132 is connected via shaft 116 and a wiper 139 therein to resistance bank terminal wire 152 with terminals of fixed resistances as 121 and 123 con¬ nected to wires 151 and 153- respectively. .The -variabl __.re.-r. sistances as 122 and 124 provide for precise quantitative calibration.

The operation of resistor control unit 29 progressively changes the values of the boundaries 251 and 252 of the con¬ trolled temperature range 253 through the resistances as 128 and 129 connected to the controller unit 30 continually and stepwise in a process as shown in FIG. VII using the appara¬ tus of FIGS. IX and X or progressively changes the bound- aries 261 and 262 of the controlled temperature range" 263 continuously or smoothly in a process as shown in ^"FIG. -VI when a continuously running motor as 141 is used to drive the wiper arm drive shaft 116^ Such progressive changes of resistance values progressively changes the position of the range of on and off control by range control unit 30 and provides the programs of on and off operation of the heating units 12 and 13 to provide a controlled drift of the effec¬ tive temperature in dwelling 16.

In the resistor control unit 29 embodiment shown in FIGS. IX and X the pulse drive mechanism 24 comprises a stepping circuit 145 and a gear drive assembly 146. The stepping circuit 145 comprises a unijunction timer circuit 111 of which the actuating switch 241 is closed when the start relay 100 is actuated at the start of the system 10 by switch 110. The unijunction timer circuit 111 is connected to a solenoid 112 which solenoid drives the gear drive as¬ sembly 146. Gear drive assembly comprises a gear train 114 and a ratchet wheel 113; the ratchet wheel 113 drives the gear train 114 and that gear train drives a drive shaft wheel 115; the drive shaft wheel 115 positions and controls the wiper arm drive shaft 116 of resistor assembly 29 on which shaft are firmly mounted wiper arms, as 131 for re- sistor unit 91, arm 132 for resistor unit 192, and like arms for each resistor unit 93-99 so that,, on initiation of operation of the cycle of* operation of unit 29, the distri¬ bution of resistance values in each resistor unit as 91-99 is regularly changed at a rate providing for a change of temperature range as 253 or 263 in dwelling 16 of 1/4 degree Fahrenheit each 15 minutes. «

The return unit 150 is connected to electrical power source 20 and comprises a switch .147, a locking circuit 148, and a trigger 149 on the shaft 116. _.The output of switch 147 is connected to drive the solenoid 117 and a motor 118 to return gear 113 to start position. Alternatively the output of switch 147 may be used to return the motor 141 and gear 142 to start position.

On termination of each cycle of operation of unit 29 as in FIG. IX, (a) the solenoid 117 is actuated by switch 147 to release the escapement lock rod 144 that normally holds the ratchet wheel 113 for stepwise motion in one, clock¬ wise, direction and (b) motor 118 turns a helically threaded shaft 154, which mates with and turns a correspondingly threaded end of shaft 143 of the ratchet wheel 113 and returns the ratchet wheel 113 and shaft 116 and wiper arms as 131 and 132 of all resistor units 91-99 to their start position.

Normally open switch 147 is closed only on release of the relay 100 and is automatically thereafter held closed by a locking timer circuit 148 until shaft 116 is brought to its start position, and then relay switch 147 is opened automatically by a trigger 149 on shaft 116. Operation of System 10 According to FIGS. VI and VII;

Human occupants as 60 in an enclosure as a room in dwelling or building 16 are comfortable although the temper¬ ature drifts so long as the rate of drift is controlled or (ramped) to a gradual change. Slow rates of temperature change, approximately 1 degree Fahrenheit per hour (0.6 deg Centigrade per hour) or less are acceptable and allow the temperature during drift to extend beyond the given appro¬ priate comfort temperature range for humans. Generally for sedentary persons, slow temperature changes from the usual neutral comfort point are indistinguishable from constant temperature conditions.

The thermostat system 10 has a narrow (1 deg F) "dead- band" as 263 in FIG. VI and 253 in FIG. VII and on each of its preselected neutral set-points, but the "dead-band" always drifts at a controlled rate when triggered by a call for heating or cooling by switches 40 or 50 and 110 of appa¬ ratus 11. ^"The system 10 does not call for heating or cool¬ ing energy input when the room temperature is within the bounds of the "dead-band" upper and lower temperature limits as 251, 252, 261 or 262. The temperature of the air in the building 16 is shown by dashed lines 260 and 259 in FIGS. VI and VII respectively. The energy input zones are shown by hatched zones 264 and 268 A-F and 254 and 258 A-F. The "dead-band" also continues at a controlled drift at times when the apparatus 11 does not call for heating or cooling so long as the rate of drift does not exceed the rate of natural temperature drift of the space. A touch of the fin¬ ger to the thermostat face plate 110 causes the "dead-band" to move back to a neutral setting, as 75 deg F in FIG. VI Limits can be set to the extent the thermostat-'s "dead-band" would drift from neutral setting.

In the preferred embodiment, the operator as 60 in dwel¬ ling 16 adjusts the thermostat unit 21 by touching start button or switch 110.The system 11 does not have the conven¬ tional dial that is set or twisted to adjust; the operator 60 touches a conductive plate or button 110 which brings the temperature setting of the thermostat as 21 to a preselected neutral point as 75 deg F in FIG. VI and FIG.VII. A ther¬ mistor sensor and humidity transducer determines when the setting is satisfied for unit 30 and in turn programs the unit 21 to start a setting change, or drift. When the start button 110 is actuated the control unit 30 comes into play and provides for bringing the environment in the dwelling 16 to a preset temperature as is sensed by thermistor 17 (and the variable resistor 170 which is a measure of sensed humi¬ dity) . After the interior of dwelling 16 is at the desired temperature a signal from the output stage 214 is produced. Such signal-'s effect on the heating and/or cooling units depends upon whether the heat control switch 40 or the cooling control switch 50 is earlier actuated.

A discriminator 301 which distinguishes between the high and low output signals of the circuit 30 is actuated by response of the circuit 30 to the conditions in dwelling 16 as measured by humidity and temperature components 17 and 19. Such discriminator 301 connects to a flip-flop switch ^• 302 which is actuated thereby and in turn actuates a time delay 303. Accordingly after a fixed time as determined by the time delay 303 the sensor unit 21 begins its program. At the time the sensor unit 21 begins its program the flip-flop 302 has been toggled and the further signals from control unit 30 do not effect the time delay unit 303 until the starter switch 110 is _.actuated to start another cycle. Dur¬ ing the period that the control unit 30 is operated it con¬ trols the heating and cooling units 12 and 13 through the relays therefor 14 and 15 respectively. The time at which the temperature sensor unit 21 becomes effective to control the system and begin the program can be actua^'ted by a fixed time delay 303 or the time delay 303 may be made variable depending upon the conditions and dynamic response of the dwelling system and its heating and ventilation and air con¬ ditioning system or a bypass switch 304 may actuate the pro- gram 21 at a time, for instance, when the occupant leaves the house or at such other time at which the occupant may desire to initiate the cycle programs provided by the sensor unit 21 and the remainder of the unit 11..

cypi 1 The immediate call by button or plate 110 is for the heat or the cooling to be brought into the temperature range as at 264 in FIG. VI or 254 in FIG. VII that the occupant, s body needs at that moment, remaining fixed at this re-set

5 temperature as 75 deg F in harmony with the response time of the heating or cooling system. Response time 265 and 255 is the time^' required for the heating or cooling equipment for dwelling 16 to bring the environment of the space to within the preselected comfort range. The button or plate 110 may

10 also be connected to sense and make minor adjustments in the preselected temperature as reflected, in a further ad¬ justable resistance in series with 17 and 170, to account for discomfort reflected by too great a difference between the temperature of the occupant?s fingers as compared to

15 normal.

Touching the plate changes' the temperature -setting-of- the thermostat to a preselected neutral/comfort set- point because the thermistor 18 and humidity transducer 190 through unit 21, assembly 22 and 23 actuates units 12 or 13

20 to effect heating or cooling, as required, to bring the room temperature in building 16 into the preselected temper¬ ature range as 75 deg. F. as shown in FIG. VI where heating is desired or 75 deg. F. as shown in FIG. VII where cooling is desired.

25 The set point will remain fixed at this reset neutral- /corafort temperature setting for a period of time, as 266^' in FIG. VI and 256 in FIG. VII which is in harmony with the dynamic^' response of the building which includes its con¬ tents and structure as well as its heating and cooling sys-

30 tern. The response times 265 and 266 will vary among systems and structures. The electronic sensor circuit 30 deter¬ mines when the set point has been satisfied and triggers a timer 304 which, when timed out, starts the set point range 263 (or 253) to slowly drift as shown in FIG. VI (and VII).

35 The following is a specific example of the winter oper¬ ation of a controlled drift apparatus 11 installed within a residential environment system as 10 (referring to FIGS. I and VI) . The occupant awakes a 6:00 a.m. and touches the ther¬ mostat start switch 110 if the room temperature feels too cool (e.g. 65 deg F) . The circuit 30 responds by calling for the preselected 75 F plus or minus 1 deg F (24 deg C plus or minus 0.6 deg C) and provides for 100% heating, and starts operation of the heating unit as at 264 in FIG. VI to sat¬ isfy the thermostat and humidity sensor setting and main¬ tains that setting until the room's Mean Radiant Temperature (MRT) approaches the room's air temperature shown by the dashed line 260 as sensed by thermistor 17 and humidity transducer 19.

The occupant leaves for work at approx 7:30 a.m. at which time the space had been warmed to an Operative Temper¬ ature of 75 F (24 deg C) by 6:30 and has begun to cool down at a rate of 1 deg F/h (0.6 deg C/h) . There will be many occasions during cool weather _^wherein well insulated resi¬ dential spaces subject to this controlled drift rate will result in no need for heating energy.

^• By 5:30 p.m. when the occupant returns home from work, the temperature within the space will be say 65 F (18 deg C) if the cold weather has continued throughout the day. Al¬ though 11.5 hours- have passed since the thermostat was touched, an 11.5 deg F (6 deg C) drop would not necessarily have occurred even if a 65 deg F (18 deg C) minimum limit had not been set. The reason is that the drift does not begin until the space temperature reaches Operative Tempera¬ ture or the delay timer times out, (shown in FIG. VI as around 6:30 a.m.). Furthermore, if at any time during the day outdoor conditions warm to the point of causing the space temperature to cease dropping, the first call for cooling merely causes the direction of drift to reverse. Upon finding the space temperature too cool, the therm¬ ostat is touched again at 5:30 p.m. to reset the thermostat to warm the space to 75 F (24 deg C) or 76 F (24.5 deg C) by 6:00-6:30 p.m., and thereafter the drifting resumes. For someone retiring by 10:00-10:30 p.m. the temperature will be no lower than 72 F (2 deg C) . It will be after midnight when the occupant is asleep and covered with blankets before the temperature drops below 70 F (21 deg C) .

The following is a specific example of the summer oper¬ ation of energy saving controlled drift apparatus 11 installed within a residential environment system as 10 (referring to FIGS. I and VII):

The occupant arrives at or awakes at 8:00 a.m. in the room and touches the thermostat start switch 110 if the room temperature feels too hot. The circuit 30 responds by call¬ ing for the preselected 75 deg F plus or minus 1 deg F (26 deg C plus or minus 0.6 deg C) .

The thermistor and humidity sensor of temperature range controller 30 call for 100% cooling by the cooling unit 13 to satisfy the thermostat and humidity sensor setting and maintains that setting and operation, as at 254 in FIG. VII until the room's Mean Radiant Temperature (MRT) approaches the room's air temperature 259 as sensed by thermistor 17" and transducer 19. The preset built-in timer circuit as 303 to delay commencement of drift may also be used to delay drift until MRT approximates air temperature 259. The occupant leaves the room- at approx 9:00 a.m. at which time the space had been cooled to an Operative Temper¬ ature of 75 deg F (24 deg C) and had begun to warm up at a rate of 1 deg F/h (0.6 deg C/h) . While there will be many occasions during warm weather wherein very well insulated residential spaces subject to this controlled drift rate will result in no need for further cooling energy.

By -5:30 p.m when the occupant returns to the room, the temperature within the space will be about 83 deg F

(28.3 deg C) if the hot weather has continued throughout the day. Although 8.5 hours have passed since the ther _t- ostat was touched, an 8.5 deg F (6 deg C) increase would not necessarily have occurred even if an 82 deg F (27.8 deg C) minimum limit had not been set. The reason is that the drift does not begin until the space temperature reaches Operative Temperature or the delay timer times out, which is shown as around 8:30 a.m. Furthermore, if ^'at anytime during the day outdoor conditions cool to the point of causing the space temperature to cease rising, the first call for cool-

- ing merely causes the direction of drift to reverse.

Upon finding the space temperature too hot, the system start switch 110 is touched again as at 5:30 p.m. to reset the thermostat to cool the space to 75 deg F (24 deg C) and the drifting resumes. For someone retiring by 10:00-10:30 p.m. the temperature will be no higher than 80 deg F (26.7 de C) if the weather had remained severely warm into the night. When the thermostat is touched upon retiring, the room temperature may tend, to rise only slightly before the normal early morning cool weather conditions prevent a fur¬ ther rise in temperature.

The system 10 above described_> has a narrow 1 deg F (0.6 deg C) dead-band 253 with boundaries 251 and 252 in FIG. VII and dead-band as 263 with boundaries 261 and 262 in FIG. VI starting on a preselected neutral/comfort set point, but the set point dead-band always drifts (to right in FIG. VII and to left in FIG. VI) at a controlled ate of 1 deg F/hr. when drifting is triggered by the system satis¬ fying a "call" for heating or cooling. The system 10 neither calls for heating as at 264 and 268 A-F or cooling as at 254 and 258 A-F so long as the room temperature 260 or 259 is within the bounds, of the dead-band upper and lower limits as 261 and 262 and calls for heating as at 264 and 268 A-F and ^*cooling as at 254 and 258 A-F only when the tem- perature of the room shown by dashed line is at the limit of the band and the circuit 30 then actuates the heating^' or cooling unit 12 or 13 of system 11. The set point/dead-band as 263 and 253 continues controlled drift when the system 11 is or is not calling for heating or cooling. The system 10 thus provides for greater dwell time in the "energy systems-off" mode periods as 257 A-G and 26^~7 A-267E than in the "energy systems on" periods 264 and 268 A-E and 254 and 258 A-F when energy is supplied to maintain the rate of drift of the air temperature as indicated by lines 260 and 259 within the band limits 263 and 253 res¬ pectively resulting in a corresponding reduction in energy consumption. A touch of the occupant' s finger to the control button plate 110 causes the set point/dead-band to move back

UK^" to a neutral setting as 75 deg F. in FIGS. VI and VII. The extent of drift of the^' set point dead-band from neutral set¬ ting (high limit and low limit) can be preset and further limited by field accessible adjustments to accommodate to different personal and seasonal conditions.

On starting the operation of the system 11 and the process as in FIG. VI or VII (by connecting the range con¬ troller unit 30) , the resistor relay 105 is automatically actuated. The resistor unit assembly 95 then provides the electrical resistances thereof (at the usual start position of assembly 95) across wires 151 and 152 and 153 to the 555 timer unit 200. Such values of electrical resistance cor¬ respond to the value of electrical resistances through the thermistor 17 and rheostat portion 170 at the desired co - fort value in the dwelling, 16 e.g. 75 deg F and 50-% rela¬ tive humidity or equivalent effective temperature. Such resistances which are initially^' connected across wires 151 and 152 and 153 remain so connected for the duration of the period of response time as 265 and the dwell time 266.in FIG. VI and 256 in FIG VII. At the end of the response timer period as for instance at 6:30 a.m. as shown in FIG. VI, and 8:30 a.m. in FIG. VII when the timer unit times out and the sensor unit 21 and control assembly 22 are then thereby automatically actuated, the sensor unit 21^' and as- sembly 22 then control the sequence of positions of resis¬ tor units as..96, 97 and 98 that are subsequently connected to unit 30 on an energy conserving heating operation as in FIG. VI; alternatively units as 94, 93, and 92 are sequen¬ tially connected to unit 30 during -an energy conserving cooling operation as in FIG. VII. The sequence of conriec- tion of the resistor units is determined by actuation of cooling control switch 40 or heating control switch 50. The operation of this system provides heating energy savings proportional to the area 267A-F between areas shown as per- iods of heating as 264 and 268A-F. The operation of this system also provides cooling energy savings proportinal to the areas 257A-G between areas shown aa periods of cooling as on 254 and 257A-F. ^{^} In the operation of the apparatus 11 on a heating cycle as in FIG. VI sensor 21 initially senses the temperature in room 16 at the operative temperature as 75 deg F. set by unit 30 and then connects a particular resistor unit, as 95 for a temperature range of 75 deg F. plus or minus 1/2 deg F. to actuate the unit 30 for the period of response 265 and dwell time 266. Thereafter relay 100 is actuated and the resistor control unit 29 commences then to automatically operate. The resistor control unit 29 then continuously and smoothly progressively changes the values of the assembly 28 resistors as 128 and 129 and thereby lowers the on-off range of reaction of range control unit 30 at the continuous rate of one degree Fahrenheit per hour (to 74 deg F. plus or minus 1/2 deg F.). When the temperature in zone 16 drops to the lower limit of the range set by unit 30, as at point 291, heating unit 12 is actuated automatically by unit 30 and the temperature in the zone 16 then rises as shown dia¬ grammatically by the room temperature path portions 292 A-F. When the unit 30 is no longer actuated the temperature of zone 16 falls as at portions 293 A-F of temperature path 260.

When the temperature in zone 16 reaches 74 deg F. the sensor unit 21 connects another resistor unit, as 94 to wires 151, 152 and 153. Such other resistor unit ^"sets the range control unit 30 at a different value than did^" the first resistor unit, 95, connected to range control unit^' 30 so that unit 30 then sets range of reaction of the heating unit 12 to drift continuously downward to 73 deg F in one hour without actuating that heating unit. When the zone 16 temperature reaches 73 deg. F the sensor unit 21 actuates another resistor unit as 93 that provides that range control unit 30 have a 73 deg. F range (plus or minus 1/2 degree F) and so permits the reaction zone or dead-band 263 to drift upwards continuously and smoothly at 1 deg. F per hour with- in a range of 1/2 degree F. The thermistors 17 and 18 are accurate to within 0.2 degree Fahrenheit.

In operation of the apparatus 11 on a cooling cycle as in FIG. VII the sensor 21 initially senses the temperature

^"BU E in room 16 at the operative temperature as 75 deg F set by unit 30 and then connects a particular resistor unit, as 95, for a temperature range of 75 deg F. plus or minus 1/2 deg F. to actuate the unit 30 for the period of response 255 and dwell time 256. Thereafter relay 100 is actuated and the resistor control unit 29 commences then to automatically operate. The resistor control unit then continually in stepwise fashion progressively changes the values of the as¬ sembly 28 resistors as 128 and 129 and thereby raises the on-off range of reaction of range control unit 30 at the rate of one-fourth Fahrenheit per 1/4 hour to 76 deg F. (plus or minus 1/2 deg F.). When the temperature in zone 16 rises to the upper limit of the range set by unit 30, as at 294, cooling unit 13 is automatically actuated by unit 30 and the temperature in the zone 16 then falls as shown dia¬ grammatically by the room temperature path at 295 A-F. " When the unit 30 is no longer actuated the temperature of zone 16 falls, as at portions 296 A-F of temperature path 259.

When the^'temperature in zone 16 rises to 76 deg F. the sensor unit 21 connects another resistor unit, as 96 to wires 151-3. Such other resistor unit sets the range con¬ trol unit 30 at a different value than did the first resis¬ tor unit, 95 connected to range control unit 30 so that unit 30 then sets the range of reaction of the cooling unit 13 to drift stepwise upward to 77 deg. F. in one hour (at 1/4 e.g. F. each 15 minutes) without actuating that cooling unit. When the zone 16 temperature reaches 77 deg. F. the sensor unit 21 actuates another resistor unit as 97 that provides that unit 30 have a 77 deg. F. range (plus or minus 1/2 de- gree F) and so permits the reaction zone or dead-band 253 to drift upward stepwise at 1 degree Fahrenheit per hour within a range of 1/2 degree F.

The particular described initial setting of the dead- bands as 263 and 253 in FIGS. VI and VII at 75 deg. F. is merely exemplary of initial settings in comfort conditions of ASHRAE standard 55-74 i.e., at effective temperature in range of 72 and 78 deg. F. (22.2 and 25.6 deg. C) and dew points of 35 and 62 deg. F. (1.7 and 16.7 deg. C.)—along the 50% relative humidity line the temperature range is 72-78 deg. F.—and more recent winter and summer comfort en¬ velopes at air movement of 30 f.p.m or less. Following such initial settings the control drift is put into operation for system 10 by apparatus 11 as above described.

The controlled stepped dead-band operation in FIG. VII is merely exemplary of a stepped controlled drift operation using the apparatus as in FIGS. IX and X and the smooth controlled dead-band operation of FIG. VI is merely illustrative of a controlled continuous drift operation using apparatus as in FIG. VII. Accordingly the stepped characteristics shown in the controlled dead-band drift cooling energy input operation of FIG. VII may also be applied to a controlled dead-band drift heat energy input operation as described in relation to FIG. VI. Also, the smooth continuous characteristic of the controlled dead-band drift in the controlled heating energy input operation shown and described in relation to the operation shown in FIG. VI may be used in an operation as shown in FIG. VII where there is a controlled dead-band drift during application of cooling energy. Operation of Humidity Sensor Assembly of FIG. XI:

Humidity sensor and control unit 160 comprises in oper¬ ative combination, and connected as shown diagrammatically in FIG. XI, a humidity transducer 19 located within a ^'wall mounted housing in the room 16, a base resistance 162,^' an amplifier transistor 163, a solenoid coil 164 within which is located a solenoid piston 165 with an extension arm 159, a piston spring 166 which biases the piston to maintain it in rest position with the piston only partially extended

.1. upwardly beyond the coil 164, an adjustment screw 167 which serves to adjust the base or rest position of the piston re¬ lative to the coil, and a bracket 176 and base plate 168 on and in which the coil 164 and arm 159 and screw 167 are supported as well as electrical components 162, 163, .170 and 180. The apparatus 160 also comprises a linkage 169 which is connected to the arm 159 of the piston 165 to actuate the wiper arm 172 of the range control unit rheostat 170 and ϋ E 1 wiper arm 192 of sensor unit rheostat 190. The humidity transducer or humidistat 19 thus actuates two rheostats, one, sensor, rheostat 190, for the sensor circuit 21 and the other, control, rheostat 170 for the control circuit 30.

5 Figure XVI shows the electrical resistance characteris¬ tics of thermistor 17 of controller 30 as well as the elec¬ trical resistance characteristics of the thermistor 18 of sensor unit 21 where both have negative temperature coeffi¬ cients. In FIG. XIII and XVI the vertical line referenced

10 as "TEMP" and shown as 178 in FIG. XIII indicates increasing temperature in an upward vertical direction and in FIGS. XIII, XVI and XVII the horizontal line referred to as "RESISTANCE" and 179 in FIG. XIII indicates increasing electrical resistance from left to right. In FIG. XVII the

15 vertical line indicated as "HUMIDITY" indicates increasing values of humility in- the upward vertical direction..

The fixed terminal 175 and wiper arm terminal 173 of the rheostat 170 are connected in the electrical circuit of the control unit 30 so that the output of that circuit 30 reacts

20 to the sum or totality of electrical resistance measurements of temperature and the humidity in the monitored and con¬ trolled zone 16. The fixed terminal 195 and wiper arm ter¬ minal 193 of rheostat 190 are connected in the circuit of the temperature sensor unit 21 so that the output of such

25 circuit 21 reacts to the sum or totality of electrical re¬ sistance measurements of temperature as 282 in FIG-1 XVI -and the humidity as 272 in FIG. XVII in zone 16.

As shown by line 270 in FIG. XVII, with a negative temperature coefficient of the humidity transducer 19 in the

30 circuit 160, with a high humidity 271 in zone 16 the elec¬ trical resistance 272 of the transducer 19 is relatively low or reduced and the current through the transistor 163 of circuit 160 is low or reduced; as a result thereof the cur¬ rent through the coil 164 is reduced and the displacement of

35 the piston 165 is small or lowered.

The linkage 169 then provides that the portion 171 of the rheostat resistance between wiper arm terminal 173 and fixed terminal 175 of the rheostat resistance 170 applied to control circuit 30 has a low value. With the circuit of unit 30 comprising a^' thermistor 17 of negative temperature coefficient as shown by line 280 in FIG. XVII the sum or combination of resistance 283 of the thermistor 17 and the resistance 273 of the humidity rheostat resistor 170 has lower total resistance than would be the case where the humidity as 272 and temperature as 282 were at lower value with concurrent higher resistances as 274 and 284 respec¬ tively. The linkage 169 also provides that the portion of the rheostat resistance 190 between terminals 193 and 195 of rheostat 190 is applied to sensor circuit 21 and has a low value, and the combination of electrical resistances of the negative temperature coefficient thermistor 18 and of the humidity rheostat resistor 190 have a total lower elec- trical resistance than would be the case where the humidity and temperatures were cool or at a lower value.

The converse is also true/ i.e. when the humidity in zone 16 is low as at 272 the resistance 273 of the humidity transducer 19 is high, the current through the transistor 163 is high and displacement of the piston 165 is large and the linkage 169 then provides that (a) a large portion of the resistor 170 is applied in series with the thermistor resistance 17 as shown in FIG. Ill while also (b) that a large portion of the resistor 190 is applied in series with the thermistor resistance 18 as shown in FIG. IV.

Accordingly, in the apparatus 11 although the actual temperature in zone 16 of the dwelling may be a given dry bulb temperature e.g. 76.3 deg F. with a high humidity e.g. 80% relative humidity the humanly sensed temperature or effective temperature would be higher e.g. 78.8 deg F at 40% relative humidity and the output line 208 of sensor 21 would provide, at 76.3 deg F and 80% relative humidity an output to the frequency selectors as 31-39 as though a high¬ er dry bulb temperature (but the same effective temperature) of 80.6 deg F at 20% relative humidity were sensed because the resistance due to the temperature as measured by a ther¬ mistor would be one value (FIG. XVI No. 283) and the resis¬ tance due to the humidity would be additional thereto (Ref- erence No. 273 on FIG. XVII) for a total resistance which would be the sura of the resistances due to the resistance of the thermistor and also the resistance due to the rheostat resistor portion 171. Thus, the control unit 30, via the humidity sensor rheostat 170 of assembly 160 provides that the humidity in the monitored zone or room is automatically taken into consideration together with the dry bulb tempera¬ ture sensed by the thermistor 17 for the control action of unit 30, i.e. a certain resistance (283 in FIG. XVI) due to the electrical resistance of the thermistor plus the resis¬ tance 273 of the unit 170 due to the humidity reading.

Further, where the actual temperature in the dwelling may be 72 deg F with a low humidity, e.g. 20% relative humidity, the humanly sensed temperature or effective tem- perature would be lower e.g. like 70 deg F at a higher e.g., 50% relative humidity and the sensor 21 automatically pro¬ vides at 72 deg F and 20% relative humidity in dwelling 16 an output at 28 to the frequency selectors as 31-39 as though a lower dry bulb temperature (of 70 deg F at higher, e.g. 50%', humidity) were sensed because the resistance due to the temperature is one a value as 283 and the resistance as 273 due to the humidity is added thereto to provide a total resistance as 284 which is as great as that corre¬ sponding to a lower dry bulb temperature as 282. .The unit 30 under such conditions, via with the sensor rheostat 170 in assembly 160 provides that humidity in the monitored zone or room is automatically taken into consideration together with the temperature sensed by the thermistor 17 for the control action of temperature range controller unit 30. The rheostats 170 and 190 are thus connected in cireuit

160 so as to provide changes in electrical resistance in circuits 30 and 21 respectively that not change in the same direction as the electrical resistances of the thermistors 17 and 18, on change increase in temperature of the interior of building or dwelling 16 but also the amount of change of the resistance of the portions of rheostat 170 and 190 con¬ nected to circuits 30 and 21 respectively ^'due to change in humidity; sensed by the transducer 19 provides an amount of

^" electrical resistance change in those portions of rheostats 171 and 191 connected to circuits 30 and 21 respectively that matches the equivalent change in temperature and humid¬ ity for comfort purposes, as set out in ASHRAE comfort chart (Hardy, J.D. Thermal Comfort and Health, ASHRAE Journal 31, pgs. 43-51, 1971 and ASHRAE STANDARD 55, Thermal and Envi¬ ronmental Conditions for Human Occupancy.)

Both rheostats 170 and 190 are connected to provide a reduced electrical resistance as the sensed humidity in- creases when, as is the case with the preferred circuit em¬ bodiment of units 160 and 30 described herein, the ther¬ mistors of the sensor and control circuits 30 and 21 also have negative coefficients of temperature as shown by lines 280 and 270 in FIGS. XVI and XVII respectively. However, the thermistors 17 and 18 used in circuits 30 and 21 respective¬ ly may have positive coefficients of" temperature, as shown in FIG. XIII, then the rheostat 170 of humidity control unit 160 would be connected at terminals 173 and 174 to the remainder of circuit 30 as shown in FIG. Il and rheostat 190 of the unit 160 would be connected at its terminals 193 and 194 to the remainder of circuit 21 as shown in FIG IV. With a thermistor having a positive temperature coefficient, as shown in FIG. XIII with a 70 deg. F temperature in zone

16, as indicated at 181 for thermistor as 17 or 18 and in view of the relationship established -by temperature coeffi¬ cient of resistance line 180 with the corresponding resistance value 183, the electrical resistance value con¬ nected to circuit 30 or 21 is increased from the electrical resistance value at 183 by an added electrical resistance value (187 in FIG. XIII) such as is provided by the rheostat portion 193-194 or 173-174 in response to the humidity con¬ dition in zone 16 as then measured by unit 160. The effect of the electrical resistance due to the humidity measurement is to reach a total resistance value of 184 because of the added effect at 187 of humidity. Such additive action pro¬ duces an inapparent higher temperature, as 72 deg. F., as indicated by referece number 186, in view of the temperature coefficient relationship of temperature and resistance at point 185 to which the sensor unit 21 reacts. By such cir¬ cuit using positive temperature coefficient components when the sensed temperature or humidity increases there is also provided automatic addition of the effect of the total of increased temperature and increased humidity to automatical¬ ly control the heating and cooling units 12 and 13 of system 11. Such system also provides decreased total electrical resistance in series with the thermistor when the sensed humidity decreases so as to provide automatic addition of the overall decreased effect of decreased temperature and decreased humidity to automatically control the units 12 and 13 of system 11.

The electrical connections of the output of the circuit of FIG. Ill are then reversed to provide for actuating cool- ing instead of heating units as below described and the re¬ lation of the sensor- unit- 21- output 208 to the frequency selector circuit assembly is reversed to provide the same functional relationships as herein described for use of the thermistors and humidity transducers with negative coeffi- cient of temperature.

Operation of Sensor Circuit 21 of FIG. IV:

When wired as an astable multivibrator as in FIG. IV the 555-type IC timer 200 is used to generate a square-wave output voltage at 208 of which the frequency has a one-to- one correspondence with temperature. A negative-tempera¬ ture-coefficient thermistor 18 is used in the IC's charging network.

The circuit's output frequency varies in a nearly linear manner from 38 to 114 hertz as temperature changes from 37 deg F to 115 deg F. At no point in this temperature range does the frequency count differ by more than plus o^"r minus 1 Hz from the corresponding temperature.

The circuit of FIG. IV uses a thermistor resistor. Transistor 205 is turned on during the charging interval and off during the discharge interval. This transistor's near-zero on-resistance and very large off-resistance result in equal charge and discharge intervals that depend on only the resistance of thermistor 18, resistor 208 and rheostat 190 . Operating f requency can then be given by :

f = 1A2 (R 18 + R 206 + R 190 ) C ln ( 2 )._→

or , at a f ixed value of C ,

f = K (R 18 + R 206 + R 190 ) .

Frequency variation with temperature, therefore, is similar to the voltage variation of the thermistor/resistor divider network. The divider's output voltage can be ex¬ pressed as:

( hR 206 + R 190. ) V out = ( ) Vcc

( kR 206 + R 190 + R 18. )

As the denominators of this equation and the frequency equa¬ tion are the same, the frequency/temperature relationship of the circuit has the same shape and degree of linearity as that of the voltage output of a conventional thermistor/re¬ sistor divider.

With a thermistor having an R value of 5,000 ohms at 25 deg C and a resistance ratio of 9.06:1 over the tempera¬ ture range of 0 deg C to 50 deg C, the circuit produces a linearity error of less than plus or minus 1 deg. F over a 78 deg F range.

The frequency count of the circuit is the same as the useful Fahrenheit temperature range (37 deg F to 115 deg F)-. In general, the frequency will be linear with respect to temperature in the 60-100 deg. F interval of interest, but the frequency count is different from the absolute value of the temperature being sensed in view of the above des¬ cribed inclusion of humidity effect.

To minimize circuit error, it is desirable to use tem- perature-stable polycarbonate capacitors. For this circuit, off-the-shelf capacitors having nominal plus or minus 5% tolerances are employed, with the final capacitance being a number of parallel capacitors hand-selected to give the cor¬ rect frequency count at a given temperature.

The IC timer itself contributes negligible error to the frequency output over temperature. Power supply by-passing may be provided to avoid sensitivity to supply voltage vari¬ ations. Operation of Temperature Range Control Unit 30 of FIG. Ill

Generally, in the circuit of FIG. Ill the thermistor- resistor divider network 128, 129, 130, 17 and 170 produces a voltage that is directly proportional to effective temper¬ ature sensed at. thermistor 17 and humidity sensor 19. When the effective temperature is rising (at a fixed value of humidity)* the output from stage 214 at terminal 3 of the 555 timer (shown as 200) is high and the threshold input volt- age at pin 6 to threshold comparator 211 is determined by the voltage divider set -up-by resistances 17, 170, and the resistances connected across input wires 151 and 152 from the resistance bank assembly 28, such as the variable over¬ all resistances 128 and ^"129 of the resistor bank assembly unit 91. Such input voltage increases as resistances across 17 and 170 decreases. When the sum of the resistance of the thermistor 17 and the humidity rheostat 170 portion connec¬ ted to circuit 30 equals the resistance at the "hot" set- point temperature (RTH) the divider relationship establishes a voltage of 2/3 Vcc at the threshold input (pin 6) . After the input to the internal comparator 211 reaches this (2/3 Vcc) level, the discharge transistor 215 is switched on, effectively placing resistance 130 in parallel with resistor bank resistances as 128 and 129. As the resistance and/or humidity drops the thermistor and/or humidity resistance increases so that the voltage is divided between (17 and 170) and (130 in parallel with 128 and 129). When the thermistor resistance and the resis¬ tance of the humidity rheostat portion in the circuit equals the resistance at the "cold" set point temperature (RTC) , the divider produces a voltage of 1/3 input voltage (Vcc) at pin 2.

More particularly, the timer's internal resistive divi- der 216, 217 and 218 establishes reference voltages at (1/3) Vcc and (2/3) Vcc fof each of the timer's comparators 212 and 211 respectively. When an external voltage applied to the threshold input pin (6) exceeds (2/3) Vcc, an output is generated by the threshold comparator 211 that toggles the flip-flop. This turns on the discharge transistor 215 and results in a low output signal from the timer.s driver amplifier output stage 214.

A discriminator circuit 301 distinguishes between high and low outputs of the output stage of unit 30 and actuates the heater unit relay 14 and heater unit 12 when heating is needed and when heating control switch 40 is actuated or ac¬ tuates the cooling unit relay 15 and the cooling unit 13 when cooling is needed and heating control switch 50 is ac- tuated; otherwise the heating and cooling units are not ac¬ tuated.

The turn-on of the timer.'s discharge transistor 215 lowers the voltage at the threshold input to less than (2/3) Vcc (at 219). If the trigger input (at 2)^", to comparator 212 then drops below (1/3) Vcc, the trigger comparator 212 generates a pulse that retoggles the flip-flop 213,. drives the discharge transistor 215 off, and causes the output stage 214 to return to its high output level.

This circuit action maintains an environment as 16 within a bounded temperature range. A voltage that is "dir¬ ectly proportional to effective temperature i.e. the^' sum of relative humidity and temperature, will rise at pin 6 along with effective temperature until threshold voltage (2/3) Vcc is reached. The output stage 214 will then change state so that a cooling unit as 13 can be turned on or a heater unit as 12 can be turned off. Effective temperature will then drop until (1/3) Vcc exists at the trigger input pin 2 caus¬ ing the output stage 214 to return to its first state with the cooler off and the heater on. For the circuit 'in FIG. Ill, the thermistor/resistor divider networks connected to pins 6 and 7 produce the volt¬ age that is directly proportional to effective temperature. When effective temperature is rising (high output state. discharge transistor 215 off) the threshold input voltage at pin 6 is determined by the division between the combination of (R17 + R170 + R128) and R129 where R17 is the electri¬ cal resistance of the thermistor 17 and R170 is the connect- ed portion, as 171 of the humidity rheostat 170 and R128 is the electrical resistance of the portion of the resistor unit of assembly 28 connected to control unit input wires 151 and 152 and R129 is the electrical resistance of the portion of the resistor unit of .assembly 28 connected to control unit input wires 152 and 153 and such input volt¬ age increases as the value of (R17 + R170) decreases.

When (R17 + R170) is equal to the thermi.stor resistance at the hot setpoint temperature, RTH, the divider relation-^' ship needed to establish %(2/3) Vcc„. at the threshold input is:

h CRth + R128)/(Rth + R128 + R129)_^ = 1/2

After an input to the threshold comparator 211 reaches this level, the discharge transistor 215 is switched on, effectively placing R130 (the electrical resistance shown as 130 in FIG. Ill) in parallel with the combination (R128 + R129).

As the effective temperature drops (R17 + Rl70) in¬ crease in value, and the division is between (R17 + R170) and %R130 in parallel with (R128 and R129)..^. When (R17 + R170) is equal to the resistance at the cold setpoint temperature, RTC, the divider must produce (l/3) Vcc at the trigger input. The divider relationship becomes: A/B = 1/2 where

A = %R130 in parallel with the series combination of (R128 + R129) and

B = ϊjR C in series with the parallel combination of ((R130) and (the series combination of R128 and R129)) .

Otherwise expressed as R130 11 (R128 + R129)/RTC + (R130 11 (R128 + R129)) = 1/2 Therefore, the impedance level of the thermistor and humidistat/resistor dividers is effectively changed depend- ing on whether the thermostat and humidistat (or humidity transducer) be in the rising temperature portion of their operating cycle or the cooling portion. This is necessary since a thermistor's resistance varies quasi-exponentially with temperature and may exhibit a two-or three-fold change over a total temperature range;* that is, the thermistor's cold setpoint resistance, RTC, may be several times larger than its hot setpoint resistance, RTH over the entire range of 65 to 95 deg F. Where a standard thermistor is used and its resistance as a function of temperature is known, as is usual, straightforward design approach applies. Where the set¬ point resistance ratio, RTC/RTH, is less than 2, as is usual over a 1 deg F range, then R128 = 0 and R129 is 2RTH, so that:

R130 = 2RTHRTC/(2RTH-RTC)

(For this analysis, the timer's trigger and threshold inputs do not load the dividers.) Thermistor power dissipation is kept as low as possible to maintain the accuracy of the thermostat's setpoints. By operating the timer from the lowest possible supply voltage-e.g. 5 volts-thermistor self- heating is minimized as well as self heating of the humidity transducer or humidistat 19.

To prevent noise signals from causing-premature state changes, the timer's trigger and threshold inputs are by¬ passed with capacitors 220 and 221 respectively (of .01 mi¬ crofarad capacity) when divider impedance levels are high, the environment is noisy, or long leads are used to connect the thermistor to the circuit. ^' Operation of Timing Circuit of FIG. X:

FIG. X is a circuit diagram of timer 111; it operates on a 24 volt power supply and provides a 15 minute or 900 second time delay between .closing of the switch 241 and fir¬ ing of the SCR 240. Such firing of the SCR 240 actuates the coil 112 of the stepping unit 146 of assembly 24. The circuit of timer 111 comprises unijunction transis¬ tor oscillator to furnish the negative pulse to the base of UJT 238 of the unijunction transistor timer. The time con¬ stant is T, and where R233 is resistance of 233 in ohms and C237 is capacitance of capacitor 237 in microfarads T = R233 x C237 = 900 seconds.

Unijunction 230 generates a quasi-sawtooth waveform at its emitter; the time period of this waveform is approxim¬ ately 10 seconds. Capacitor 235 couples the negative-going portion of this waveform to the base 242 of unijunction 238. The amplitude of the negative pulse at. base 242 is on the order of 1 volt. (Routine test with the value of capacitor 235 will yield the most desirable value.) If the pulse is too large in amplitude, unijunction 238 will fire too early; if the pulse is too small, firing may be erratic. The uni¬ junction 230 sends a pulse to unijunction 238 once^" every 10 seconds. This structure provides a 15 minute timer. Exem¬ plary electrical component values of circuit 111 are set out in Table I. Values of the circuit elements of FIG. V are set out in Table II.

TABLE I

No. Value

230 transistor 2N1671B

231 20 ohm resistor 232 1 meg ohms

233 15 meg ohms

234 220 vhm

235 .001 microfarad capacitor

236 10 microfarad capacitor 237 60 microfarad capacior

238 transistor 2N1671B

239 20 ohm

240 SCR

241 switch (closed by actuation of 100) input = 24 volts

^"BϋRE TABLE II

Data on Circuit of FIG. V Ref No. Description

216 5K ohms

217 5 ohms

218 5K ohms

311 4.7K ohms

312 830 ohms

313 4.7K ohms

314 IK ohm

315 6.8K

316 3.9K

317 7K ohms

318 10K ohms

319 4.7K ohms

320 220 ohms

321 ' 100K ohms

322 4.7K ohms

Pin 1 ground

2 trigger

3 output

4 reset

5 control voltage

6 threshold

7 discharge

8 Vcc input voltage

Source: Service Signetics Corporation , Sunnyvale, Califor¬ nia as SE 555/NE555

Electrical characteristics are set out at pages 1-6, Table 1-2, of "The 555 Timer Applications Sourcebook, With Experi ments", Howard M. Berlin 1976, Capital City Press, Montpelier, VT 05602.

Claims

Claims

1. A temperature and humidity sensing and control pro¬ cess to modulate heating and cooling of air in a space in a building, said process comprising the steps of sensing air temperature and humidity of said air and providing an output signal proportional to said air temperature and humidity

-and thereby initially controlling heating and cooling units connected to said space and bringing said air in said space in said building to standard comfort conditions and then maintaining said conditions for a predetermined period of time and thereafter permitting the temperature of air in said space to drift at a controlled rate within a pre-selec- ted dead-band range in an energy conserving direction.

2. Process as in claim .ϊ wherein said comfort con¬ ditions comprise temperature and humidity conditions in the effective temperature range of 72 degrees to 78 degrees Fah¬ renheit and dew points of 35 degrees and 62 degrees Fahren- 5 heit.

3. Process as in claim 2 wherein said temperature of said air drifts at a rate of no more than 1 degree F. per hour.

4. Process as in claim 3 wherein said temperature of said air drifts at the rate of 1 degree F. per hour.

5. Process as in claim 3 wherein said temperature of said air drifts continuously.

6. Process as in claim 3 wherein said temperature of said air drifts in a stepwise manner.

7. Process as in claim 5 wherein said temperature of said air drifts upward.

-BURE

8. Process as in claim 5 wherein said temperature of said air drifts downward.

9. Process as in claim 6 wherein said temperature of said air drifts upward.

10. Process as in claim 6 wherein said temperature of said_. air drifts downward.

11. A temperature sensing and control process to modu¬ late heating and cooling of air in a space in a building, said process comprising the steps .of sensing temperature of said air and providing an output signal proportional to said air_^ temperature and thereby initially controlling heating and cooling units connected to said space and bringing said air in said space in said buildings to standard comfort con- ditions and then maintaining said conditions for a prede¬ termined period of time and thereafter permitting the tem- perature of air in said space to drift at a controlled rate within a pre-selected dead-band range in an energy con¬ serving direction.

12. Process as in claim 11 wherein said comfort conditions comprise temperature conditions in the effective temperature range of 72 degrees to 78 degrees Fahrenheit^".

13. Process as in claim 12 wherein said temperature of said air drifts at a rate of no more than 1 degree F. per hour.

14. Process as in claim 13 wherein said temperature of said air drifts at the rate of 1 degree F. per hour.

15. Process as in claim 13 wherein said temperature of said air drifts continuously.

16. Process as in claim 13 wherein said temperature of said air drifts in a stepwise manner.

o.ypi

17. Process as in claim 15 wherein said temperature of said air drifts upward.

18. Process as in claim 15 wherein said temperature of said air drifts downward.

19. Process as in claim 16 wherein said temperature of said air drifts upward.

20. Process as in claim 16 wherein said temperature of said air drifts downward.

21. Temperature sensing apparatus for modulating air heating and cooling apparatus connected to a space within a building comprising means sensitive to air temperature in said space and connected through a condition measuring means having an output proportional to said air temperature to a control means, said control means comprising means connected to said heating and cooling apparatus and said control means comprising first programming means to actuate said heating and cooling apparatus to bring said air in said space in said building to standard comfort conditions and then main- tain it at said conditions and said control means compris¬ ing a second programming means to progressively change at a predetermined rate conditions to which said control unit reacts whereby to permit the effective temperature in said space to change from said standard comfort conditions at a controlled and unnoticeable rate within a pre-selected dead- band range in the energy conserving direction.

X 22. Apparatus as in claim 21 comprising a house heat¬ ing control unit, a house cooling control unit, said heat¬ ing control unit and cooling control unit being operatively connected to said heating and cooling apparatus in said building, said control means being a program control apparatus comprising, in operative connection, a power source, a cycle selector assembly and a temperature control assembly, the cycle selector assembly comprising an effective temperature sensor unit and a logic unit assembly, and a series of like electrical units each sensitive to the output of said effec¬ tive temperature sensor unit, said temperature control assembly comprising a resistor bank assembly and a resistor control unit and a temperature range control unit, the temperature range control unit being a 555 integrated circuit timer, said resistor bank assembly comprising a series of like connected and arranged and act¬ uated resistor unit assemblies, each of said resistor unit assemblies comprising electric resistors .having a different value of electrical resistance than other resistor unit as¬ semblies in the resistor bank assembly, said resistor con¬ trol unit comprising a drive means for providing progressive changes of resistance values of said resistor unit assem¬ blies, different portions of each of said resistor un-itr-as—^■ semblies connected between different pairs of resistor ter¬ minal wires which are connected to an input of the temper¬ ature range control unit.

23. Apparatus as in claim 22 wherein the resistor control unit comprises a stepping circuit which provides timed and stepped increments of change of resistance value of the resistors of the resistor bank assembly connected to the - input of the temperature range control unit.

24. Apparatus as in claim 22 wherein the resistor con¬ trol unit comprises a drive means providing continuous change of values of electrical resistances connected to the input of the temperature range control unit.

X 25. Temperature and humidity sensing apparatus for modulating air heating and cooling apparatus connected to a space within a building comprising means sensitive to air temperature and to humidity in said space and connected through a condition measuring means having an output propor¬ tional to said air temperature and humidity to a control means, said control means comprising means connected to said heating and cooling apparatus and said control means com¬ prising first programming means to actuate said heating and

10 cooling apparatus to bring said air in said space in said building to standard comfort conditions and then maintain it at said conditions and said control means comprising a second programming means to progressively change at a pre¬ determined rate conditions to which said control unit reacts

15 whereby to permit the effective temperature in said space to change from said standard comfort conditions at a controlled and unnoticeable rate within a pre-selected dead-band range in the energy conserving direction.

1 26. Apparatus as in claim 25 comprising a house heat¬ ing control unit, a house cooling control unit, said heat¬ ing control unit and cooling control unit being operatively connected to said heating a-nd cooling apparatus _in. said

5 building, said control means being^" a program control apparatus comprising, in operative connection, a power^" source, a cycle selector assembly and a temperature control assembly, the cycle selector assembly comprising an effective temperature

10 sensor unit and a logic unit assembly, and a series of like electrical units each sensitive to the output of said effec¬ tive temperature sensor unit, said temperature control assembly comprising a resistor bank assembly and a resistor control unit and a temperature

15 range control unit, the temperature range control unit being a.555 integrated circuit timer, said resistor bank assembly comprising a series of like connected and arranged and act¬ uated resistor unit assemblies, each of said resistor U"nit assemblies comprising electric resistors having a different

20 value of electrical resistance than other resistor unit as¬ semblies in the resistor bank assembly, said resistor con¬ trol unit comprising a drive means for providing progressive changes of resistance values of said resistor unit assem¬ blies, different portions of each of said resistor unit as-

25 semblies connected between different pairs of resistor ter¬ minal wires which are connected to an input of the temper-

^• ature range control unit.

27. Apparatus as in claim 26 wherein the resistor control unit comprises a stepping circuit which provides timed and stepped increments of change of resistance value of the resistors of the resistor bank assembly connected to 5 the input of the temperature range control unit.

28. Apparatus as in claim 26 wherein the resistor con¬ trol unit comprises a drive means providing continuous change of values of electrical resistances connected to the input of the temperature range control unit.

29. Apparatus as in claim 26 comprising a humidity transducer located within a wall mounted housing in said building and control rheostats in said effective ^"temperature^" sensor unit and in said range control unit, the humidity transducer operatively connected to said rheostats through a rheostat actuating means.

30. Apparatus as in claim 29 wherein one of said rheo¬ stats connected to said humidity transducer is serially con¬ nected to a thermistor in an electric circuit of said range control unit and another of said rheostats is serially con¬ nected to a thermistor in an electric circuit of said effec¬ tive temperature sensor unit whereby to add the effects of measurements by said humidity transducer and by said thermistors.

31. Apparatus as in claim 30 wherein said humidity transducer and said thermistor both have positive tempera¬ ture coefficients of resistance.

32. Apparatus as in claim 31 wherein said humidity transducer and said thermistor both have negative tempera¬ ture coefficients of resistance.

33. Apparatus as in claim 32 wherein said rheostats are connected to provide changes in the electrical resis¬ tances in the temperature sensor circuit and in the temper¬ ature range control unit that change in the same direction on increase in said air humidity and in said air tempera¬ ture.