Abstract:
A thermostat-controlled heater/cooler is used to condition air in a temperature-controlled region. A target temperature is obtained and compared to the temperature of the region to determine if heating/cooling is required. If yes, then outside air is directed into the region without operating heater/cooler and updated temperatures of the region are measured. The directing and measuring are continued until (1) the measured temperature equals the target temperature, at which time control returns to the obtaining a target temperature step, or (2) the updated measured temperature differs from the target temperature by a chosen amount, and in some examples, if the updated temperature does not reach the target temperature within a chosen length of time, or the target temperature changes, or the program segment ends, at which time directing outside air into the temperature-controlled region is stopped and the heater/cooler is operated under control of the thermostat.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to thermostats used to control heating and cooling systems, such as gas or electric forced air furnaces, gas or electric radiant heating furnaces, electric forced air air-conditioning systems, and electric heat pumps. Invention may also be suitable for other types of systems, including solar and solar electric heating and cooling systems. While many systems provide both heating and cooling, the invention is suitable for use with systems that provide heating or cooling or both heating and cooling, often collectively referred to as a heater/cooler. 
     Programmable thermostats typically use a screen, such as a liquid-crystal display (LCD), to display both operational functions and programming values. The user enters commands into the thermostat, such as for setting the current time and date and programming the thermostat, by pressing keys or pressing appropriate positions on a touch screen display. Programming conventional thermostats is often accomplished by selecting a series of different screens on the display. In addition to making entries using a touch screen display, thermostat often include additional button type inputs. 
     High energy efficiency of buildings is often achieved in part by substantially reducing air infiltration into the building. One of the drawbacks of such tightly constructed buildings is that the air inside the building can become stale and often permits buildup of harmful or at least objectionable components in the air. The advantages that can be achieved by using controlled amounts of ambient, outside air to reduce these air quality problems when heating or cooling the building are well known. Some conventional systems cycle the air in the building or permit outside air to be introduced into the building at periodic intervals, such as for five minutes every hour, or by a special air purge cycle, typically when the building is not occupied. Other conventional system may permit the heater/cooler to incorporate a chosen percentage of outside air into the air being heated or cooled. See, for example, U.S. Pat. Nos. 2,372,839; 4,018,266; and 6,491,094. An exemplary thermostat is the Robertshaw model 9914i made by Invensys Controls of Carol Stream, Ill. 
     BRIEF SUMMARY OF THE INVENTION 
     One aspect of the invention is the recognition that it may be possible to use ambient air as is, that is without heating or cooling it, as the first stage of heating or cooling the inside of a building or other temperature-controlled region. Doing so provides the dual advantage of providing fresh, outside air into the building without the need to use energy to heat or cool the air. For example, in some regions of the country daytime temperatures can be quite high, such as 95° F., but after sunset the outside temperature cools off quite quickly, such as to 70° F. while the temperature of the house has been maintained at 78° F. by the heater/cooler. Thus, the present invention takes advantage of this and provides for a first heating/cooling stage that uses outside air to, in this example, cool the building. Similarly, in some situations the outside air, typically air adjacent to a building and, in particular, adjacent to a south facing wall of the building, can be sufficiently heated by the sun to enable it to be used to heat the inside of the building, or other temperature-controlled region, without the need to use energy to heat the air. 
     In one example, the invention is directed to a method for operating a heater/cooler controlled by a thermostat. The heater/cooler is operable to condition air in a temperature-controlled region within an ambient environment of outside air. A target temperature is obtained. The temperature of a temperature-controlled region is measured by a thermostat with the thermostat operating according to a program segment. The target temperature and the measured temperature are compared to obtain an Initial Temperature Difference between said temperatures. Whether or not heating/cooling is required is determined based upon said Initial Temperature Difference. If heating/cooling is required, then proceed as follows. Direct outside air from the ambient environment into the temperature-controlled region without using the heater/cooler to change the temperature of the outside air. At least periodically measure the temperature of the temperature-controlled region to obtain an updated measured temperature. The directing and measuring steps are continued until (1) the measured temperature equals the target temperature, at which time control returns to the obtaining a target temperature step, or (2) the updated measured temperature differs from the target temperature by a chosen amount, at which time directing outside air into the temperature-controlled region is stopped and the heater/cooler is operated under control of the thermostat. 
     In some examples, the directing and measuring steps are continued until (1) the measured temperature equals the target temperature, at which time control is returned to the obtaining a target temperature step, or (2) any one of the following occurs, at which time outside air is stopped being directed into the temperature-controlled region and the heater/cooler is operated under control of the thermostat: the updated measured temperature differs from the target temperature by a chosen amount; or the updated temperature does not reach the target temperature within a chosen length of time; or the target temperature changes; or the program segment ends. 
     In some examples, if heating/cooling is required, then, before the direct outside air step, the temperature of the outside air is sensed. If the temperature of the outside air is at least X° above the target temperature when in a heating mode or is at least Y° below the target temperature in the cooling mode, then proceed with the direct outside air step. If the temperature of the outside air is not at least X° above the target temperature when in a heating mode or is not at least Y° below the target temperature in the cooling mode, then operate the heater/cooler under control of the thermostat. 
     In another example, the invention is also directed to a method for operating a heater/cooler controlled by a thermostat. The heater/cooler is operable to condition air within a temperature-controlled region. The temperature-controlled region is within an ambient environment of outside air. A selection is made between a fan on mode and a fan auto mode. A circulate mode is selected or not selected. If the fan on mode is selected, then outside air from the ambient environment is directed into the temperature-controlled region whether or not the heater/cooler is operating to change the temperature of the air within the temperature-controlled region. If the fan auto mode is selected and the circulate mode is not selected, then outside air from the ambient environment is directed into the temperature-controlled region when the heater/cooler is operating to change the temperature of the air within the temperature-controlled region. If the fan auto mode is selected and the circulate mode is selected, then outside air from the ambient environment is directed into the temperature-controlled region: (1) when the heater/cooler is operating to change the temperature of the air within a temperature-controlled region, and (2) for a minimum length of time per time period. 
     Various features and advantages of the invention will appear from the following description in which the preferred embodiments have been set forth in detail in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of an example of a thermostat made according to the invention with the display showing a home screen; 
         FIG. 2  shows a menu screen of the thermostat of  FIG. 1  displayed after pressing the menu input of the thermostat of  FIG. 1 ; 
         FIG. 3  shows a manual screen of the thermostat of  FIG. 1  displayed after pressing the + or − buttons or the current temperature on the home screen of  FIG. 1 ; 
         FIG. 4  is a simplified schematic of a heating/cooling systems including the thermostat of  FIG. 1  coupled to a heater/cooler; 
         FIG. 5  illustrates exemplary terminal connections among the thermostat, baffle and furnace/AC unit of  FIG. 4 ; 
         FIG. 6  is a flowchart showing the operation of the heating/cooling system of  FIG. 4  in an Add Fresh Air mode; and 
         FIG. 7  is a flowchart showing the operation of the heating/cooling system of  FIG. 4  in a Fresh Air As First Stage mode. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description will typically be with reference to specific structural embodiments and methods. It is to be understood that there is no intention to limit the invention to the specifically disclosed embodiments and methods but that the invention may be practiced using other features, elements, methods and embodiments. Preferred embodiments are described to illustrate the present invention, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a variety of equivalent variations on the description that follows. Like elements in various embodiments are commonly referred to with like reference numerals. 
       FIG. 1  illustrates one example of a thermostat  10  made according to the invention. Thermostat  10  includes a body or housing  12  containing a touch screen display  14 . Thermostat  10  also includes an increase or up input  16  and a decrease or down input  18  adjacent to display  14 . Thermostat  10  also includes a home input  20 , a menu input  22  and a power/mode input  23 . Inputs  16 ,  18 ,  20 ,  22  and  23  are, in this example, button type inputs although other type of inputs could also be used. Touching home input  20  returns display  14  to a home screen  24 , an example of which is shown in  FIG. 1 . In this example, home screen  24  displays the current temperature  26 , a target temperature  28 , and a HEAT/COOL/AUTO/OFF mode indicator  30 . Other information can also be provided, such as at a date and time indicator  32 , humidity indicator  34 , radio link indicator  36  and alphanumeric power alert indicators  38 ,  40 . When the existence or warning of a power alert has been transmitted to thermostat  10 , such as through a radio link, information regarding the energy crisis is provided at alphanumeric energy alert indicators  38 ,  40  and green, yellow and red status lights  42 ,  43 ,  44 . The various features described above can be of conventional or unconventional design. Examples of thermostats are disclosed in US patent application publication number US-2006-0186214-A1 published 24 Aug. 2006 and in U.S. Pat. No. 6,824,069 issued 30 Nov. 2004, the disclosures of which are incorporated by reference. Examples of power alert type of systems are shown in U.S. Pat. Nos. 6,671,586 issued 30 Dec. 2003 and 6,650,249 issued 18 Nov. 2003 and in US patent application publication US 2008/0185451 published 7 Aug. 2008, the disclosures of which are incorporated by reference. 
     Thermostat  10  is preferably a programmable thermostat which allows the user to change the operating temperature over the course of the day and typically allowed each day to be programmed differently. For example, assume the thermostat is in a heating mode, a typical programmed heat profile includes the following program segments: 62° F. from midnight to 6 AM; 70° F. from 6 AM to 8:30 AM; 64° F. from 8:30 AM to 4 PM; 68° F. from 4 PM to 10 PM; and 62° F. from 10 PM to midnight. The higher heating mode temperatures, 68° F. and 70° F. in this example, are typically called target temperatures or target operating temperatures while the lower heating mode temperatures, 62° F. and 64° F., are typically called the setback temperatures or setback operating temperatures. 
     One problem with conventional programmable thermostats arises when a user wishes to change the operating temperature without having to reprogram the thermostat. For example, assume the user gets up earlier than usual and leaves at 7 AM. There is typically no convenient way to permit the user to move the current operating temperature from the morning target temperature of 70° F. to the associated setback temperature of 64° F. Note that the associated setback temperature is typically the setback temperature following the current target temperature and the associated target temperature is the target temperature following the current setback temperature. To help address this problem, in one example, thermostat  10  comprises a save energy input  45  which allows a user to toggle the operating temperature of the thermostat between the current target temperature and the associated, that is the next, setback temperature by simply pressing save energy input  45 . Thus, in this example, the user can simply press save energy input  45  at 7 AM causing the operating temperature change from 70° F. to the associated setback temperature of 64° F. at 7 AM instead of 8:30 AM. Similarly, if the user arrives early at, for example, 2:30 PM, simply pressing save energy button  45  causes the operating temperature to change from the current setback temperature of 64° F. to the associated operating temperature of 68° F. 
     In another example, save energy input  45  operates as follows. By pressing save energy button  45 , the target temperature for the current program cycle will be changed, increased in cooling mode and decreased in heating mode, by a preset offset, typically from 1° F. through 9° F. The amount being changed will be visible on display  14 , such as “Save Energy A 4°.” This offset can be adjusted using the up and down inputs  16 ,  18 . This save energy feature can also be remotely controlled, such as by a radio signal from the power company during a power crisis. An example of such a system is shown in patent publication US 2008/0185451, the disclosure of which is incorporated by reference. Note that in some power crisis systems, the power company can determine the amount of the offset, which may be different from a user selected or hardware manufacturer selected offset. 
       FIG. 2  illustrates a menu screen  50  which is shown on display  14  when menu input  22  is pressed. Pressing PROGRAM input  52  causes a program screen to be shown on display  14 . The program screen is used to set a daily time/temperature schedule when in the heat or cool modes. COMFORT input  54  is used to maintain an appropriate temperature level consistent with a desired level of efficiency. HUMIDITY input  56  is used to select minimum and maximum humidities when the heating/cooling system  58 , shown in  FIG. 4 , includes a humidifier. CONSUMABLES input  60  allows the user to monitor the remaining life for parts of the system, such as air filters, humidifier pads and ultraviolet bulbs, that have limited lives and need periodic replacement. HVAC SET-UP input  62  is used to configure thermostat  10  to control the heating cooling system  58 . AMI CONFIGURATION input  64  is used to configure power company network connections when the system can be under partial control of the power company during, for example, a heat wave creating the need to reduce power consumption. See, for example, US patent application publication US 2008/0185451 published 7 Aug. 2008. HOME AUTOMATION CONFIGURATION input  66  is used when configuring home automation network connections. CALIBRATE input  68  is used to allow the user to change the value of the displayed current temperature  26  to, for example, the current display temperature of another thermostat. For purposes of this invention, what is important are the home screen of  FIG. 1  and the manual screen of  FIG. 3  so that the other inputs and screens associated with menu screen  50  will not be described in detail. 
     Manual screen  70 , shown in  FIG. 3 , is accessed from home screen  24  when power/mode input  23  has been placed in heat or cool modes by either pressing up input  16 , down input  18  or current temperature  26 . Thermostat  10  could, of course, the design to permit access to manual screen  70  in other ways. The current target temperature  28  can be temporarily changed from manual screen  70  by using up and down inputs  16 ,  18 . Doing so will cause the target temperature to be temporarily changed for the current program segment of thermostat  10 . When a new program segment begins, the program&#39;s target temperature for that segment becomes active. Note that the target temperature for the program segment just before midnight is typically the same as the target temperature for the program segment just after midnight. Also, note that in this example, in manual screen  70 , current temperature  26  shown on the home screen  24  is not visible. Pressing HOLD  72  allows the current target temperature to be changed from the present program&#39;s target temperature to any other temperature, to be used indefinitely, that is during the current program segment and all future program segments, until HOLD  72  is pressed again. Pressing HOLIDAY  74  activates a preset holiday program while pressing PROGRAM  76 , located just below HOLIDAY  74 , allows the user to set up a holiday program. A holiday program is a single program that repeats day after day until turned off. It supersedes any weekly program. Pressing VACATION  78  immediately changes the target temperature from the program to target temperature to a preset, so-called vacation target temperature that the user can select, to be used indefinitely, that is during the current program segment and all future program segments until VACATION  78  is pressed again. Therefore, the basic difference between HOLD and VACATION is that with HOLD the user must select the temperature to be used while with VACATION the temperature used is preprogrammed, typically by the user. EMERGENCY HEAT  80  is, in this example, displayed only when system  58  includes a heat pump and an auxiliary heat source, commonly an electric resistance heater. When EMERGENCY HEAT  80  is selected, the heat pump is disabled and the auxiliary heat source is the sole source of heat. This manual override remains active until removed by once again pressing EMERGENCY HEAT  80 . 
     HEAT  82  is displayed when the system is in heating mode. When in a cooling mode, the word HEAT is replaced by the word COOL. FRESH AIR  84  is pressed when the heater/cooler  86  of system  58  has a fresh air baffle  88  to permit outside air  90  to be used instead of inside air  92 . This feature is described in more detail below with reference to  FIGS. 4 ,  5  and  7 . 
       FIG. 4  illustrates heating cooling system  58  within a building  94  or other structure having a temperature-controlled region  96 . In  FIG. 4  heater/cooler  86  is shown within building  94  but generally outside of temperature-controlled region  96 . Heater/cooler  86  could also be located wholly or partially in one or more of the outside of building  94 , inside of temperature-controlled region  96 , or inside a building  94  but outside of temperature-controlled region  96 . Heater/cooler  86 , in this example, includes a combined furnace/air-conditioning (AC) unit  98 , an air inlet  100  connected to a blower or fan  102 , and an air outlet  104  connected to conditioned air inlet ducts  106 . Air inlet ducts  106  deliver conditioned air to temperature-controlled region  96 . Fan  102  has an air inlet  108  connected to the outlet  110  of fresh air baffle  88 . Fresh air baffle  88  has a fresh air inlet  112  connected to outside air  90  through a fresh air duct  114 . Fresh air baffle  88  has a return air inlet  116  connected to temperature-controlled region  96  by return ducting  118 . As shown in  FIG. 5 , fresh air baffle  88  is connected to and controlled by thermostat  10  with power provided by furnace power terminals  120 . Other configurations for powering and control of fresh air baffle  88  can also be used. For example, fresh air baffle  88  could be powered by a battery or by a rechargeable battery connected to a small power generating turbine placed just upstream of air inlet  108  of fan  102 . Also, fresh air baffle could be controlled by thermostat  10  using wireless technology. 
     The display and selection of the various fan functions are initiated from home screen  24  of  FIG. 1  by first pressing on power/mode input  23  and then pressing on fan icon  126 . Pressing on fan icon  126  causes the fan functions (in this example, AUTO, CIRC (CIRCULATE), ON, and FRESH) to be displayed; one or more of the fan functions can be selected by pressing on the displayed fan function. The one or more fan functions which have been selected are highlighted. AUTO indicates that fan  102  operates automatically with the operation of furnace/AC unit  98 . CIRC indicates that fan  102  operates automatically to circulate air for up to nine minutes per hour to improve air quality and efficiency. ON indicates that fan  102  operates continuously whether or not furnace/AC unit  98  is operating, that is heating or cooling the air. FRESH indicates that the fresh air baffle  88  is open so that both outside air  90  and inside air  92  can be driven into conditioned region  96  by fan  102 . In one example, the following different fan functions or groups of fan functions can be selected. First, ON; second, ON plus FRESH; third, AUTO; fourth, AUTO plus FRESH; fifth, AUTO plus CIRCULATE; sixth, AUTO plus CIRCULATE plus FRESH. 
     Two different fresh air procedures will now be discussed. The first procedure, outlined in  FIG. 6 , is initiated from home screen  24  of  FIG. 1  by pressing on power/mode input  23  to select the fan mode at  124 . To select the fresh air mode at  128 , fan icon  126  is pressed and then FRESH is selected by touching it. The fresh air mode is used when it is desired to operate fresh air baffle  88  so that fan  102  pulls outside air  90  into furnace/AC unit  98  and then into region  96 . The user is then given the option at select  130  to select either FAN ON or FAN AUTO. 
     If FAN ON is selected, fresh air baffle  88  is actuated open at  131  as shown in  FIG. 4 . This causes the fan  102  to draw outside air  90  through fresh air duct  114  and into the air inlet  108  of the fan and mix with the inside air  92  drawn through return air inlet  116 . Fan  102  will run, and therefore draw both inside air  92  and outside air  90  through the heater/cooler  86  and into conditioned region  96 , whether or not heater/cooler  86  is running, that is heating or cooling the air passing through it. 
     If FAN AUTO is selected when the fresh air mode is active, and if CIRC has not been selected as indicated at  129 , fan  102  will run, as indicated at  132 , and therefore draw outside air  90  through fresh air duct  114 , draw inside air  92  through return ducting  118  and force the mixture of both into air inlet  108  of the fan, through the heater/cooler  86  and into conditioned region  96 ; this occurs only with the operation of heater/cooler  86 , that is when heater/cooler  86  is heating or cooling the air passing through it. When heat or cool shuts off, fan  102  turns off and baffle  88  closes to seal off fresh air inlet  112 . 
     If FAN AUTO is selected when the fresh air mode is active, and if CIRC has been selected as indicated at  129 , fan  102  will run, as indicated at  133 , and therefore draw outside air  90  and inside air  92  through the heater/cooler  86  and into conditioned region  96 , (1) with the operation of heater/cooler  86 , that is when heater/cooler  86  is heating or cooling the air passing through it, and (2) for at least a minimum length of time per time period, such as 5-9 minutes per hour. When fan  102  is running, fresh air baffle  88  is actuated at  133 . When fan  102  is not running, baffle  88  closes to seal off fresh air inlet  112 . In some examples, fresh air baffle  88  can be designed to seal off the return air inlet  116  some or all of the time fresh air  90  is being drawn into region  96  by fan  102 ; in such cases instead of modifying fresh air baffle  88  so that it can be used to seal off return air inlet  116 , an additional baffle can be used along return ducting  118 . 
     The second procedure is outlined in  FIG. 7 . Generally speaking, this procedure causes heating/cooling system  58  to use outside air  90  as the first stage of a heating or cooling program when the temperature of the outside air is appropriate. This procedure is initiated with the mode in either of the heat or cool modes. This second procedure will be discussed assuming thermostat  10  is in the heat mode indicated by HEAT  82  in  FIG. 3 . The procedure works similarly when in the COOL mode. Fresh air  84  on manual screen  70  is then pressed to initiate the second fresh air procedure of  FIG. 7 . Thermostat  10  then determines the programmed or otherwise selected target temperature (TT) at  134 , measures the temperature within temperature-controlled region  96 , typically referred to as the room temperature, at  136  and then compares the target temperature and the room temperature at  138  to obtain a difference between the temperatures called the Initial Temperature Difference. A decision is made at  140  based upon on the Initial Temperature Difference. For example, assume system  58  in a heating mode, the temperature swing is 1° F. and the target temperature is 70° F. If the measured room temperature is at least 69° F. then there would be no need for additional heat. When heating or cooling is not required, control is returned to  134 . 
     If there is an outside temperature sensor present and if heating or cooling is required, thermostat  10 , in this example, senses the outside air temperature at  144 . 
     If the answer at  146  is yes, so that outside temperature is at least X° above the target temperature when in a heating mode or at least Y° below the target temperature when in a cooling mode as indicated at  146 , then control passes to  142 . At  142  thermostat  10  provides an appropriate signal to open fresh air baffle  88  to connect fresh air ducting  114  to air inlet  108  of fan  102 , and turn on fan  102  causing outside air  90  to be driven into region  96  of the building  94  to heat or cool region  96  with outside air  90 . Typically X and Y are each about 2° F. or more. 
     Following  142 , system  58  continues to operate with fresh air baffle  88  open as indicated at  150 . During the operation, the room temperature is at least periodically measured to obtain Updated Room Temperature measurements. System  58  continues to operate until the room temperature equals the target temperature, at which time control is returned to  134 . However, if one of the following four events occurs, control is passed to  152  causing baffle  88  to close, thereby sealing off fresh air inlet  112 . First, control is passed to  152  when the Updated Room Temperature differs from the initial room temperature by more than, in one example, 3° F. in the wrong direction (moving colder or down when heating and warmer or up when cooling). Second, control is passed to  152  if the Updated Room Temperature does not reach the target temperature within a length of time, such as 30 minutes. Third, control is passed to  152  if the current program segment of thermostat  10  ends and next program segment starts. Fourth, control is passed to  152  if the target temperature changes. This is followed by  148  at which heating/cooling system  58  operates according to the current program segment of thermostat  10 . 
     If there is an external temperature sensor and the answer at  146  is no, so that outside temperature is not at least X° above the target temperature when in a heating mode or is not at least Y° below the target temperature when in a cooling mode as indicated at  146 , then control passes to  148 . At  148  heating/cooling system  58  operate according to the current program segment of thermostat  10  with fresh air baffle  88  closed. 
     In other examples, the outside air temperature sensing steps  144  and  146  are omitted as indicated by the no answer at  144 . In such examples, if heating or cooling is required as in  140 , control passes directly to  142  at which thermostat  10  provides an appropriate signal to open fresh air baffle  88  to connect fresh air ducting to air inlet  108  of fan  102 , and turn on fan  102  causing outside air  90  from fresh air ducting  114  and inside air  92  from return ducting  118  to be driven into region  96  of the building  94  to heat or cool region  96  with outside air  90 . 
     Other modification and variation can be made to the disclosed embodiments without departing from the subject of the invention as defined in following claims. 
     Any and all patents, patent applications, and printed publications referred to above are incorporated by reference.