Energy saving thermostat

An energy saving thermostat adapted to be connected to a remote temperature conditioning apparatus for controlling the temperature of air in a space maintains a first temperature during a first time period and a second energy saving temperature during other time periods of the day. The thermostat has a visual indicating means so that when a manually settable switch is pushed, a time interval counter means is energized for indicating and storing a series of pulses each indicative of an hour of setback time into a storage means. The thermostat also has a review button for reviewing the stored time by pulsing the visual indicating means for the number of hours of the time period energy saving temperature.

BACKGROUND AND SUMMARY OF THE INVENTION 
Clock thermostat apparatus for controlling the temperature in a space at a 
normal controlled temperature during certain periods of time and reducing 
the controlled temperature to a lower temperature for heating and a higher 
temperature for cooling or during other selected periods of time for 
energy conservation are broadly old. An early thermostat of this type is 
shown in the Carl G. Kronmiller U.S. Pat. No. 2,558,617 which issued June 
26, 1951. Over the years many other clock thermostats have been developed, 
both mechanical or electrical time mechanism, such as the thermostat 
disclosed in the Arlon D. Kompelien application, Ser. No. 639,523, filed 
Dec. 10, 1975, as well as a more complicated electronic thermostat as 
disclosed in the John M. Whitney U.S. Pat. No. 4,248,375, issued Feb. 3, 
1981. Thermostats of this type have been placed on sale by the applicants' 
assignee in the form of the T8084A Dial Set Chronotherm Thermostat, the 
T8082A Chronotherm Fuel Saver Thermostat, and the T800A Microelectronic 
Fuel Saver Thermostat. With the advent of a more concentrated effort for 
energy saving, the market for a less expensive minimal feature energy 
saving thermostat has greatly increased. 
The present invention is concerned with a minimal feature energy saving 
thermostat which provides an electronic temperature sensing and control 
circuit to maintain the temperature during a first period of time with a 
means to reset the control temperature to an energy saving temperature 
during a second period of time. The second period of time is manually 
settable in the thermostat by a time interval counter means which provides 
electrical pulses to a visual indication device and to a storage means for 
storing a number of pulses indicative of time intervals as the pulses are 
visually counted for the energy saving temperature period of time. By 
means of a review switch, the stored pulses can be reviewed by the visual 
indication device to determine the energy saving temperature time period.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, the minimal feature energy saving thermostat or 
temperature control apparatus 10 is shown connected by a five wire cable 
11 to a remote temperature conditioning apparatus 12 such as a furnace or 
a refrigeration heat pump. Thermostat 10 has a temperature control point 
adjustment member 13 which is moved from left to right to adjust a 
potentiometer and to position an indicator 14 on a temperature scale to 
select a desired temperature in the space 15 in which the temperature is 
being controlled. A second lower scale is for the temperature indication 
as might be accomplished by a conventional bimetal moving pointer 20. A 
system switch member 21 is shown for selecting either cooling, off, or 
heating, depending upon the position of member 21. A temperature setback 
or deviation from the normal control point is selected by member 22 which 
is shown at the 0.degree. setback or deviation. Upon moving member 22 to 
the 15.degree. setback, when thermostat 10 is in a setback temperature 
operating mode, the temperature would be 15.degree. from the selected 
temperature previously mentioned in connection with member 13. A more 
specific explanation of the setback or deviation operation is described in 
the mentioned John M. Whitney U.S. Patent. 
Switch or button 23 is a manually operated set (S) switch which provides 
the time established for the setback temperature control. Switch or button 
24 is to change (C) the operation of the thermostat from the normal 
temperature to the setback temperature and vice versa. Switch or button 25 
is to obtain a review (R) of the setback time. The operation of switches 
23, 24 and 25 will be described in more detail later in the specification. 
Referring to FIG. 2, a circuit diagram of the thermostat is shown. An 
electronic bridge circuit 31 contains a space temperature responsive 
resistance element 32, a temperature control point selection potentiometer 
33 which is adjusted by member 13, and a deviation circuit 34 which is 
adjusted by the position of member 22. The bridge circuit has an output 
which is fed into the main temperature control integrated circuit 35 which 
is shown in more detail in FIG. 3. By the adjustment of member 13, 
potentiometer 33 selects the temperature at which the bridge is balanced 
and thus the temperature control point of the thermostat. By the 
adjustment of member 22, various portions of resistances at 34 are 
included in the bridge circuit to modify the control point to provide for 
the temperature setback or deviation from the temperature control point 
selected by member 13 similar to the disclosure of the mentioned John M. 
Whitney application. 
The output at 36 of bridge circuit 31 upon being connected to the 
integrated thermostat circuit 35 provides for the output at connections 40 
and 41 as pulses to control the operation of a relay 42 through the 
integrated circuit regulator 39 shown in detail in FIG. 4 to either close 
or open a switch 43. Temperature conditioning apparatus 12 of FIG. 1 
connected over wires 11 is controlled in a manner as selected by system 
switch 21 to provide heating or cooling in space 15. A system fan of 
apparatus 12 is controlled in a conventional manner by switch 46. A 
temperature responsive high limit switch 47 is contained in the sub base 
to be responsive to the temperature in space 15. 
Referring to FIG. 3, thermostat control circuit 35 is shown in more detail. 
A temperature control circuit or logic 50 (shown in FIGS. 3C, 3B, 3E, 3F, 
3H and 3I) contains as a part an anticipation counter circuit or logic 51 
(shown in FIGS. 3C, and 3F) for the temperature control circuit 35. 
Circuit 50 has connected thereto the output 36 (shown in FIG. 3I) of 
bridge circuit 31 as shown in FIG. 2 to provide the output at terminals 40 
and 41 (shown in FIG. 3I) to control relay 42. A counter chain and 24 hour 
timer circuit 52 provides an output to a LED (light emitting device) or 
indicating device 30 through driver 53 of FIGS. 3A and 3B and driver 
circuit 60 of FIG. 3D and to a memory 54 (shown in FIGS. 3D and 3E) to 
select a second time period during which a signal modifies the control 
temperature of the temperature control circuit 50 as selected by the 
setback or deviation selector 22 for a second period of time as would be 
stored in the memory 54. 
Specifically, when the set switch 23 (shown in FIGS. 1, 2 and 3H) is 
manually pushed by the home owner at some particular time such as 10:00 
o'clock in the evening, a number of hours or increments of time for a 
second period of time is stored in the memory 54. In more detail, upon 
closing switch 23, counter chain and 24 hour timer 52 produces an 
electrical pulse of a three second duration as shown graphically in FIG. 
5. The pulse set memory circuit 54 energizes the LED driver 53 to produce 
an output to the LED output driver circuit 60 to energize the indication 
means or LED 30 on the thermostat to provide an indication that subsequent 
light pulses should be counted. A subsequent pulse chain is then provided, 
one pulse for each hour of setback as shown in FIG. 5. These pulses 
energize the LED and are stored in the program memory circuit 54 to store 
a predetermined number of hours for the second setback temperature time 
period in the memory. 
Thereafter, upon 24 hour timer 52 going through a 24 hour operation, the 
output of the 24 hour timer is compared with memory 54 through the energy 
saving logic circuit 61 (shown in FIG. 3A). At the time the setback period 
is set, a signal is fed to the temperature control circuit 50 through one 
of the output terminals to modify bridge circuit 31 at circuit 34 (in FIG. 
2) for a lower temperature control level depending on the position of the 
setback member 22. Output circuit 48 is for heating and output circuit 49 
is for cooling. 
At any time, upon a closing of the manual review switch 25 (R) of FIGS. 1, 
2 and 3G, memory 54 will be interrogated to provide an output through LED 
driver 53 and circuit 60 at the visual indication means 30 of the stored 
time previously set in the memory. The closing of switch 25 causes the 
program review logic of the memory circuit 54 to pulse the LED output 
driver circuit 60 once for each hour similar to the graphical showing in 
FIG. 5. By counting the number of visual pulses, the number of hours of 
delay that is stored in the memory is indicated. 
A change switch 24 (C), shown in FIGS. 1, 2 and 3G, of the energy saving 
circuit 61 shown in FIG. 3A provides for a change in the operation of the 
temperature control circuit from one control mode to the other. Thus, if 
the control circuit is in the energy saving mode and the home owner wishes 
to return to the normal temperature selected by lever 13, upon operation 
of the change button or switch 24, the normal temperature is maintained 
until the next setback time period. 
OPERATION OF THE PREFERRED EMBODIMENT 
With the minimal feature energy saving thermostat, the home owner can 
select a normal temperature control by the position of lever 13 as shown 
in FIG. 1. Temperature control circuit 50 by the operation of the relay 
42, controls the temperature conditioning apparatus to maintain that 
temperature in space 15. Such a control is accomplished for either heating 
or cooling, depending upon the position of system switch 21 and the 
capability of the temperature conditioning apparatus 12. 
To provide a night setback or change in the mode of operation of the 
thermostat to select a different temperature during a certain time period 
for both comfort and energy saving, a setback or deviation selector 22 is 
adjusted to select the amount of setback desired. When the thermostat 
moves into the setback condition, the temperature deviates by an amount 
selected by 22 from the control temperature selected by lever 13 in an 
upward or lower manner depending on whether the system switch is in 
cooling or heating. 
To select the temperature setback time period or a second period of time of 
operation, switch 23 (S) is manually closed at the particular time when 
setback is to take place. For example, if the home owner wishes to set 
back the temperature during the heating season at 10:00 P.M. on a 
particular day, switch 23 is closed and counter chain 52 produces a series 
of pulses to the LED 30 as shown in FIG. 5. The first pulse is of a three 
second duration to indicate to the home owner that the energy saving time 
period will be programmed. The three second time period prevents momentary 
accidental closings from upsetting a previous programmed condition. 
Subsequently, the pulses are shorter and each pulse of the LED 30 is for 
each hour of the second or setback period of time desired. If the home 
owner wanted a setback temperature until 7:00 A.M., a nine hour setback 
period is selected. By holding button 23 downward until the LED flashed 
nine times, a nine hour delay is stored in the memory. Thereafter each 24 
hour period or each day at 10:00 P.M. the temperature of the space is set 
back by the deviation amount selected by lever 22. For example, if the 
normal temperature was set by member 13 to control at 68.degree., and the 
setback deviation was selected for 15.degree., the setback temperature 
then drops to 53.degree. for the nine hours until the control temperature 
was reestablished at 68.degree. at 7:00 A.M. in the morning. 
At any time, the home owner can review the time period which is stored in 
the memory by pushing review button (R) 25 which flashes LED 30 a number 
of pulses depending on how many hours are stored in memory 53. Such a 
review has no effect upon the stored memory time, but only gives the home 
owner an opportunity to know the length of time of the setback period. 
The change button or switch (C) 24 provides for an overriding of the 
temperature control mode to move the control from the existing control 
mode to the other mode. If the thermostat is in the setback time period 
and the home owner wishes to have the normal 68.degree. temperature, by 
operating the change switch 24, the temperature control is restored to the 
68.degree. control point until the next 24 hour time period expired, or 
10:00 P.M. the next night, at which time the normal setback operation 
takes place. 
As previously mentioned in connection with the circuit of FIG. 3, the 
invention is not limited to one particular program. A second set button, 
such as 23, would provide for a dual setback time period if such is 
desired, by a connection made at input 70 in FIG. 3A. Such would be 
particularly desirable for a family where the home is not occupied during 
the day so that a night setback can be accomplished from 10:00 P.M. to 
7:00 A.M., and a daytime setback such as 9:00 A.M. to 5:00 P.M. can be 
obtained.