MXPA97009620A - Thermostat system, which has a proportion of optimize temperature recovery range - Google Patents

Abstract

The present invention relates to a thermostat system in a space having a current space temperature, which changes to an occupation temperature, is achieved at an occupancy time, the change in the current space temperature caused by a heater or Cooler, which has a recovery start time that occurs at a recovery time before occupancy time, the recovery time is a period of time required for the current space temperature is changed to the occupation temperature, the recovery determined by an optimized recovery ramp speed of a certain amount of space temperature change per unit of time, comprising: a first temperature sensor for detecting the current space temperature; a second temperature sensor for detecting the temperature external environment external air current but close to space, a processor, connected to the first and s Eight temperature detectors that have a memory, instruction processor and a synchronizer, a space temperature change unit that has a heater and a cooler, and a heating and cooling mode selector connected to the processor and the unit to change the temperature. space temperature, and where: the start time of recovery is at the beginning of a recovery time period before the occupancy time, when the current space temperature will be approximately the same as the occupation temperature, the time of Recovery is determined by a recovery ramp rate of a certain amount of temperature change per unit of time, and the recovery ramp rate is based on (1) a difference between the current space temperature and the outside ambient temperature recovery start time, (2) a thermal-time constant based on a ratio of a temperature difference Average temperature between the current space temperature and the outside ambient temperature current during the recovery time when the space temperature is changed to be approximately the same as the recovery temperature, and of a time change rate of the current space temperature during the recovery time, (3) a thermal-time constant for a previous period of a recovery time that has a similar time of day, and (4) a recovery ramp speed for the previous period of recovery that has a similar hour of d

Description

THERMOSTAT SYSTEM, WHICH HAS A PROPORTION OF OPTIMIZED TEMPERATURE RECUPERATION RAMP BACKGROUND OF THE INVENTION A relatively simple procedure to save on the cost of heating or cooling a space, consists of changing the reference temperature for the thermostat when the space is not busy, or in the case of a home, at night when the occupants are asleep. However, since it is not physically possible to heat or cool the controlled space instantaneously to maintain the comfort of the occupants, it is necessary that the space temperature control unit (air conditioner or furnace) begin to change the temperature of the room. space, before the time when the occupation is scheduled again. Next, it refers to the time of day when the temperature in a space will reach a higher energy use level (comfort level) as an occupancy time and the selected temperature for that occupation interval as the occupation temperature. It should be noted that this definition also includes the upper temperature, which is typically chosen during a warm-up phase of space temperature control and that follows a nightly interval back to the reference value even when, in a strict sense the space never It has been busy. The time interval during which the space temperature returns to the occupation temperature from a temperature that requires less energy to maintain, is referred to as the recovery interval, and the time of the day on which the recovery interval begins is the recovery start time. The time in which the temperature of the space reaches the occupation temperature is the current recovery time. Since there is typically a temperature range centered on the occupation temperature, or another reference point temperature for that reason, the actual recovery time will be considered in the following discussion that has been reached when the space temperature first enters this range Of temperature. The length of the recovery interval depends on the thermal load at which the space is subjected for two different and various reasons. If one is in a heating mode, for example, the lower ambient temperature will require a longer recovery interval, ie the space will take longer to warm up to the occupation temperature, because the thermal load in the space is high. If the ambient temperature is low and the period of return to the reference value is long, the temperature of the space will reach the temperature back to the reference value, further increasing the recovery time. On the other hand, a higher ambient temperature can provide a sufficiently reduced thermal load that the space does not reach its temperature back to the reference value and therefore the difference between the temperature of the space at the time the recovery interval begins, and the occupation temperature is small, and the space temperature increases rapidly equally, because there is a smaller thermal load to overcome the furnace. The analysis is similar to return to the reference value of air conditioning at a higher temperature and then a subsequent recovery interval at the lower occupancy temperature. The invention to be described is equally applicable to heating and cooling, but for convenience, the description will primarily be directed to a heating situation and this is considered unless stated otherwise. Typically, the programming of the times and temperatures back to the reference value and recovery is carried out in a thermostat physically charged in the controlled space. The most modern of these thermostats include a small microprocessor and a convenient control and display panel, allowing an internal clock to be set and the desired time and temperature for each particular period of time to be supplied by the space manager. The thermostat to be described, is controlled by the operation of a digital processor type microprocessor. It is convenient to start each recovery interval at a time that will place the temperature of the space at the occupation temperature very close to the occupation time. After all, what is the purpose of accurately selecting the return times to the reference value and occupation, if the associated occupation temperatures are not achieved with reasonable precision. But this is not easy to do precisely, because a number of independent variables are difficult to take into account when designing an economical thermostat. For example, the speed at which the individual heating units can heat a space is variable. As mentioned, the temperature of outdoor air, solar radiation, internal loads and wind can vary dramatically from one day to the next, further increasing the uncertainty regarding the thermal load in the space against which the heating unit must work. It is possible to include detectors that can measure these variations in a certain proportion. Accordingly, it will be advantageous to design a thermostat having a recovery method that is relatively sensitive to factors that affect the recovery time and yet does not require expensive detectors to measure these factors. One approach used in the past was to record recent recovery periods, and to base the current forecast for the recovery time required in recent recovery times. This approach reveals measuring the time for the temperature of the space to travel some temperature range, while the space temperature control unit operates to determine a temperature change rate, and then use this rate of change with a factor of adjustment to determine the appropriate recovery start time. Alternatively, another approach presents a process where the current space temperature is measured periodically and when it crosses a time-temperature line defined as the recovery ramp speed, and represented by a straight line, then recovery begins. However, the main disadvantages of these approaches are that they do not take into consideration the variable speed at which a space can be heated or cooled. Additionally, these approaches do not include means to take into account the temperature of outdoor air, solar radiation, internal loads and wind which, as previously mentioned, can vary dramatically from one day to the next. The lack of taking into account these parameters, which undoubtedly affect the speed of recovery, further increases the uncertainty regarding the thermal load of the space. COMPENDIUM OF THE INVENTION In a first embodiment of the present invention, an outdoor air temperature detector is used in a thermostat to more accurately determine the recovery ramp speed in which a space returns to its occupancy temperature ( recovery speed or ramp speed then) from its current temperature (CT) and thus provides an accurate selection of the time at which recovery should begin. In this scheme, the CT is measured periodically and when the CT crosses the time-temperature line defined by the ramp speed, recovery is then initiated. This invention employs regular calculations of the time required to recover the next occupancy temperature (OT) from the current space temperature as prescribed by the equations presented herein. When the difference between the present time and the next occupancy time becomes less than the time of the ramp recovery, the approach forecasts will be required to return to the occupation temperature at the desired occupation temperature, then recovery begins. In a second embodiment of the present invention, the recovery speed is approximated by a straight line that is then used to forecast the time required to recover to the next occupation temperature. The use of a ramp-based determination of the appropriate recovery start time takes into account the current room temperature, the current outdoor air temperature, the recovery speed during the previous recovery period and the time-thermal constants. For example, in some circumstances, the space can be cooled by only a few degrees during a return interval to the reference value. In this case, the ramp will be crossed by the CT relatively late in the period back to the reference value, because the space only requires heating a few degrees. If the slope of the ramp has been selected with reasonable accuracy, only an increased thermal load can make the predicted recovery time too short. But unfortunately, a too short recovery time is only briefly inconvenient or uncomfortable instead of harmful. Decreases in the thermal load considered can result in a predicted recovery time that is too long. This situation simply reduces d slightly the energy savings achieved in controlling back to the reference value of the space temperature. In an improvement for this approach, the ramp speed or recovery speed is updated based on the error in time at which the recovery has been completed in return intervals to the previous reference value. For the present invention, the equations used to adaptively optimize the recovery ramp speed, and therefore the recovery start time, as a function of the current space temperature (CT), the current outside air temperature (OAT or Toa at time t which is the present moment) the recovery ramp rate of the previous recovery period (RR) ?, and the thermal time constants rx and t2, respectively for the previous and present recovery periods, are based on the following considerations. What follows is a mathematical derivation of optimizing the temperature recovery ramp rate as a function of the measured ambient air temperature, the detected space temperature, and the ramp speed calculated the previous day for the similar recovery period ( Am or PM) . An energy balance in a thermal system, for example a residential building, results in the following equation for the rate of change in time of the detected space temperature. dt or UA dt. / dt where mcp = Total thermal capacity of space Ts = Temperature of space detected at time UA = Coefficient of total thermal transfer of the system and Toa = Ambient air temperature outside of time t. In equation (2), the ratio of the total thermal capacity of the MCP space to the total thermal transfer coefficient of the UA system is commonly known as the total thermal time constant of the system t *, which is expressed as d = fficP (3) AU Substituting equation (3) in equation (2) you get dT dt Those with skill in the specialty will notice that once a thermal system has been defined, its thermal-time constant as defined by equation (3) will not vary significantly on a daily basis, specifically between two consecutive days in particular . However, it should be noted that since the heat transfer and heat properties of any material can vary with its temperature, the time constant of the thermal system during cold low temperatures of the winter months may supposedly be different than those during the warmer upper temperatures of the summer months. Specifically, those with skill in the specialty will notice that the coefficient of thermal transfer UA, will be different during the winter months than during the summer months, and that it is also influenced by wind speed, wind direction and many other factors. In the most general case, equation (4) can be used as follows to determine rj ?, the thermal-time constant of the N system. [dT? / dT] "(5) where [Tß - Toa] N is the average temperature difference between the detected space temperature current and the outdoor air temperature during a period of time, when the air conditioning plant space is "ON"; and [dTß / dT] H is the change-time rate of the space temperature detected during this same period of time. Equation (5) when used in any two days will provide the total thermal-time constants rs,! and rs, 2 for the first and second days, respectively. For this, the more general discussion, the "two days" do not have to be consecutive days. In fact these can be any two days with the two days that occurs after day 1. In this way, the equation is obtained [dts / dtj2 (7) where sub-indices 1 and 2 refer to day 1 and day 2, respectively. Now, any difference in the time constants between these two days can be expressed as a relation of the two total thermal-time constants X *, x_ = ld, 2 (8) Combining the equations 6, 7 and 8 we get d, _ [TB-Toa] 2 / [dTß / dt] 2 or ao) General equation (10) provides a method for adaptively optimizing the ramp rate of temperature recovery by taking into account varying ambient air temperatures between two days , and also take into consideration any differences in the thermal constant-total system time between those same two days. The two days under consideration may or may not be consecutive. In a more special case, if it is considered that the total time constant of the system does not vary between two days under consideration, ie? = 1.0, then equation (10) can be written as It should be noted that equation (8) also provides an ability to verify the integrity of the thermal system, in this case a residential building between two periods. In this way equation (8) can be used for system diagnostic purposes (ie the building). Any degradation in the thermal performance of the system will be reflected in the value of?. For example, if the thermal resistance of a building has degraded due to condensation of moisture in the insulation of the building (for example a wall, ceiling, etc.), then the value of? will change to reflect this change in the thermal integrity of the building. Furthermore, a dramatic change in environmental factors such as wind speed and / or outdoor air temperature and / or incident solar energy in the exterior and / or interior components of the structure, will also affect the value of? Many other examples and applications such as this can be documented. A thermostat back to the reference value that adjusts the start of recovery by using a considered or predicted rate of cooling or heating during a recovery interval from a temperature for energy saving, includes a temperature detector that provides an indicative signal of the current space temperature CT, a temperature detector that provides a signal indicative of the current outdoor air temperature (OAT) and a programmable digital processor that includes a plurality of internal operand memory locations. At least one of these operand memory locations contains an occupancy time value that is a time of day and an associated occupancy temperature value and another that contains a ramp speed value. The processor also includes feeder channels that receive the temperature detector signals, and an output channel that provides an operation signal to initiate the operation of a space temperature control unit (which includes a heater or a cooler) that it responds to a predetermined internal condition of the processor. The processor periodically converts the temperature detector signals to digital current temperature values and stores the current temperature values in internal operand memory locations. The processor further includes a clock that maintains a present time value at a location of internal operand memory that specifies the present time of the day. The processor also includes an instruction memory from which instructions can be retrieved to be executed by the processor and where a sequence of instructions is stored whose execution begins with a recovery instruction and which, when executed, begins with the recovery instruction, causes that the processor comprises the following means implementing the invention within the thermostat. Temperature difference means recover from their respective operand memory locations the room temperature and ambient air temperature, generate a temperature difference value equal to the difference between the room temperature and the ambient air temperature, and store the temperature difference value in an operand memory location. Means for estimating the rate of change of time in space temperature during a plant "ON" cycle, recover from their respective operand memory locations, the space temperature values at the beginning and end of the "ON" period plant, calculate the difference between these two temperature values, and then divide the difference value of -temperature for the corresponding duration of the cycle of "ON" of the plant to give the speed of change over time in the space temperature and store the rate of change in time in the space temperature in an operand memory location. Means for determination of thermal-time constant recover from their respective operand memory locations, the difference between the space temperature and the ambient air temperature and the change-time rate in the space temperature, divide the value of temperature difference by the speed of time change in the space temperature to give the thermal-time constant and store the thermal-time constant in an operand memory location.

Means for determining the recovery ramp speed for the current recovery period, retrieve from the respective operand memory locations the temperature recovery ramp rate for the previous similar recovery period (AM or PM), the difference of temperature between the room temperature and the ambient air temperature at the start of the current recovery period, the temperature difference between the room temperature and the ambient air temperature at the start of the similar pre-recovery period (AM or PM), the thermal-time constant for the current recovery period and the thermal constant-time for the similar previous recovery period (AM or PM), means for calculating the temperature difference ratio as the ratio of temperature differences between the temperature of space and ambient air temperature, at the start of the current recovery period at day temperature difference between the space temperature and the ambient air temperature at the start of the similar pre-recovery period (AM or PM), means to calculate the ratio of thermal-time constants, such as the ratio of the thermal constant-time for the similar previous recovery period (AM or PM) to the thermal constant-time for the current recovery period and means to calculate the product of the temperature recovery ramp rate for the similar previous recovery period (AM or PM), and the temperature difference ratio the thermal constant-time ratio and store the product as the recovery ramp rate for the current recovery period, and store the recovery ramp rate for the current recovery period at a location of operand memory. Time difference means recover the next occupation time value and the present time value from their respective operand memory locations, generate a time difference value equal to the difference between the next occupancy time and time present and store the time difference value in an operand memory location. Ramp delta means from their respective operand memory locations, the time difference value and the ramp speed value, generate a delta ramp value equal to the product of the time deference value and the ramp speed value , and stores the ramp delta value in an operand memory location. Finally, the reference point means retrieves the next occupancy temperature value and the delta ramp value from its respective operand memory locations forms a ramp reference value equal to at least one of i) the difference between the following reference point temperature value and delta ramp value and ii) the sum of the next reference point temperature value and ramp delta value and compares the ramp reference point value with the value of current temperature. The pre-determined internal processor condition comprises a pre-determined magnitude ratio between the ramp reference point value and the current temperature value, and when the pre-determined internal processor condition exists, the processor issues the recovery signal. Which of the two ramp reference point values are used depends on whether a heating or cooling recovery is programmed. An important feature of the first embodiment of this invention is a way to adaptively optimize the value of the recovery ramp speed, based on the difference between the space temperature and the outside air temperature at the start of the recovery period, the constant value of the thermal-time type at the start of the recovery period, the value of the thermal constant-time for the previous similar recovery period (AM or PM) and the recovery ramp speed experienced during the similar previous recovery period ( Am or PM) . An important feature of the second embodiment of this invention is the determination of the recovery ramp rate experienced as the ratio of the difference between the space temperatures at the start and end of the recovery period to the time duration of the recovery period. , i.e. the rate of change in time of the space temperature during the recovery period and storing the ramp speed value in the data cell storing the ramp rate value. An important feature of the third embodiment of this invention is a way of updating the ramp speed value depending on the accuracy with which previous recoveries have occurred. This correction is implemented within the thermostat processor as a lost-time recording medium that receives the following reference point value and the present time value and when the predetermined internal processor condition first occurs, store in an operand memory location. the difference between the occupation time value and the present time value as a lost time value; and means for using ramp rate value that receive the time lost value and the ramp speed value from their respective operand memory locations, to calculate an updated ramp speed value equal to the speed value of ramp plus the product of the lost time value and a fractional value and to store the updated ramp speed value in the data cell that stores the ramp rate value. An important feature of this invention is the process for adaptively modifying the recovery ramp rate experienced during the similar pre-recovery period (AM or PM), so as to minimize the time lost. This invention involves the operation of an electronic processor of some kind. Typically, this processor can be a programmable microprocessor with the method steps implemented by the program instructions. But it is also possible to have a dedicated integrated circuit in which the processor comprises individual circuit elements carrying out the steps of the invention. In this method implemented by the processor for controlling the temperature operation back to the reference value of a thermostat, the processor includes an operand memory and an output channel that provides an operation signal for starting operation of a control unit of a thermostat. space temperature such as an air conditioner or an oven. This method comprises the steps of: a) recording in the operand memory each current value of the space temperature and current value of the outdoor air temperature; b) recording in the operand memory, at least one occupation temperature and an occupancy time following a temperature range of reference value; c) record the current time of the day in the operand memory; d) recording a ramp speed value in the operand memory; e) recording in the operand memory, each of the values of thermal constant-time for the current recovery period, the previous similar recovery period (AM or PM) and during a period of "ON" of the plant; f) record in the operand memory the differences between the space temperature and the outdoor air temperature; g) recording in the operand memory the speed of time change of the space temperature, during a cycle of "ON" of the plant; h) recording in the operand memory the rate of change in time of the space temperature during each recovery period for the day; i) calculate an updated recovery ramp speed value equal to the product of the temperature recovery ramp rate for the previous similar recovery period (AM or PM) and the ratio of the temperature difference between the space temperature and the ambient air temperature at the start of the current recovery period at the temperature difference between the room temperature and the ambient air temperature at the start of the previous similar recovery period (AM or PM) and the thermal-time constant ratio for the similar pre-recovery period (AM or PM) to the thermal-time constant for the current recovery period, and to store the product as the recovery ramp ratio for the current recovery period at an operand memory location; j) at the end of pre-determined length intervals, calculate a time difference value equal to the difference between the occupation time and the present time and record the time difference value in the operand memory; ) after a time difference value has been recorded, calculated and recorded in the operand memory, a ramp delta value equal to the product of the most recently recorded time difference value and the ramp speed value; 1) calculate and record in the operand memory a ramp reference point value equal to at least a of the differences between the occupation temperature value and the ramp delta value and the sum of the occupation temperature value and the ramp delta value; and) comparing the value of the ramp reference point with the current temperature value, and when there is a selectable relation between the ramp reference point value and the current temperature value, issuing the operation signal. It is also strongly preferred to update the ramp speed value as explained in connection with the apparatus version of the invention briefly described above. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a thermostat mounted in a space to control the temperature of this space according to the teachings of the invention. Figures 2 and 3 are graphs that reveal recovery ramp speeds for hotter and cooler previous days, respectively of the related art and the present invention. Figures 4A, 4B and 4C reveal a logical flow diagram for a sequence of instructions of a first embodiment of this invention that when executed in the appropriate microprocessor within a thermostat will cause the microprocessor and thermostat to constitute the invention.

Figure 4D is a logical flow diagram for a sequence of instructions that is used instead of Figure 4C and showing a second embodiment of this invention. DESCRIPTION OF THE MODALITIES In Figure 1, an entire space temperature control system including a controlled space 10 is illustrated, where a thermostat 12 illustrated in block diagram form is mounted. The thermostat 12 controls the operation of a node 28 and an air conditioner 29 which together comprise a unit for space temperature control 27, to provide heated or cooled air through the duct 30 to the controlled space 10. The operation of the thermostat 12 is controlled by a microprocessor 13 which includes an instruction processor 15, to execute instructions stored permanently as a program in an instruction memory 14 and which is provided as a request by the processor 15. The results of arithmetic and logical operations by the Processor 15 instructions are stored in a memory of operand 16 and then retrieved as subsequently required when executing the instructions in the program. The various arithmetic registers used by the instruction processor 15 are part of the operand memory 16. A clock module provides interruptions to the execution of instructions by the processor 15 at pre-determined intervals, for example every second. Each interruption causes execution of instructions that increments the contents of a clock location within operand memory 16. By properly adjusting a value representative of the current time of day at the clock location, a current day time value will be continuously available on the microprocessor 13. This can be done because the user manipulates the keyboard properly. The current time is constantly available to the microprocessor 13, to determine times at which the recovery intervals should start. The microprocessor 13 further includes an input / output I / O (I / O) unit 19 by which the microprocessor 13 can communicate with the external data source (the microprocessor) and target elements through input channels and output of the I / O unit (I / O) 19. In the thermostat 12, these external elements include an outdoor air temperature detector 17, a space temperature sensor 23, a keyboard 22 and a display unit 21. The temperature detectors 17 and 23 provide supply channels, signals to the I / O unit (I / O) 19, indicating the current temperature or current of the external ambient air and the current air temperature in the controlled space, respectively. At regular intervals the instruction processor 15 executes instructions that store the current temperature values of the detectors 17 and 23 at appropriate locations of operand memory 16 by converting the analog to digital data detector signals, if necessary. The keyboard 22 provides in a feed channel, power data to the I / O unit (1/0) 19 to choose reference point of occupation temperature and times desired by the occupants, as well as to adjust the necessary initial conditions of the thermostat 12. The display unit 21 displays information received via an output channel with respect to the operation of thermostat 12. This information includes the current time of the day, current day of the week, current temperature, heating phase or current cooling, and information provided by the keypad 22 to adjust the lap times to the reference value and occupancy (OTI) and temperatures (OTE). In particular, this invention involves the microprocessor 13 to select the appropriate recovery start time (RST = recovery start time) and in which a signal of operation is issued on the path 20 that begins at the recovery at an occupancy temperature. This recovery start time will always fall during a return interval to the reference value when the space temperature is maintained at a relatively low energy consumption level, less in heating mode and higher in cooling mode. When starting the return to the occupation temperature during the return interval to the reference value, the space temperature will reach the occupation temperature closest to the specified occupancy time. This recovery start time depends on both the occupation temperature and the occupation time (such as AM or PM). Therefore, it is allowed to load desired occupancy times and the associated occupancy temperature for each from the keypad 22 at sites within the operand memory 16. It can be considered that there is at least one OTI and its associated OTE within the memory. of operand 16. Operand memory 16 also has at one location a ramp rate value (RR = Ramp Rate) that is initially pre-set to a pre-defined value. In the first mode, this pre-defined value is -13.6 ° C (5.5 ° F) / hour. The ramp speed value which is the current estimated average speed at which the unit 27 can return the space temperature to the OTE value. It is said "estimated", because the current ramp speed varies with time and conditions in a not very predictable and non-linear way. A feature of this invention is the ability to change the ramp speed based on the previous performance of the method to choose RST, and in this way both improve the future accuracy to choose RST and change the method as stations change. Another feature of this invention is the ability to adaptively optimize the recovery ramp rate in response to changing conditions such as outside air temperature, solar and / or internal charge, wind speed and direction, etc., which affects the thermal load and the thermal-time constant of the space and the system. An operation signal is provided from the I / O unit (I / O) 19 via an output channel to the path 20 and when present, means the control unit 27, which activity is required either by the oven 28 or the air conditioner 29. Which of these devices will be active is chosen by a double tandem double release mode switch 25 illustrated in Figure 1, which is in the heating position. When the switch 25 is thrown to the alternating position, the path 20 is connected to the path that carries the operation signal to the air conditioning unit 29. The second tandem switch 25 provides a mode signal to the unit E / S (I / O) 19 on the path 24 by which the desired mode of operation of the thermostat 12 can be communicated to the microprocessor 13. In the simplified design illustrated in Figure 1, the path 24 is grounded when in the mode of heating and is open when in cooling mode. The execution of the instruction mode program 14 by the instruction processor 15 controls the entire operation of the thermostat 12. It will be understood that the program contained in the memory 14 has physical form since when it is recorded, it forms current physical characteristics within the memory 14 that can be detected and distinguished as coding the particular digital format of the program. As the instructions of the program are executed, in effect the microprocessor 13 is caused to sequentially become a number of different means, each of these means exists during the time in which the related instructions are executed. If these of these means are the elements of the invention. Furthermore, the invention can also be defined in terms of process steps, which have the ultimate objective of controlling the operation of the control unit 27 in a more advantageous manner. From this point of view, each of these process steps is intended to affect the physical structure of the microprocessor 13 or another device where these stages are implemented. Of course it is well known to be familiar with microprocessor technology that each of these method steps by which a process such as this invention can be defined alternately, cause detectable physical changes within the operand memory 16. The program permanently stored within the instruction memory 14 can be represented as a flow chart, and Figures 4A, 4B and 4C are the portion of that flow chart that belongs to the first embodiment of the invention and Figures 4B and 4D constitute the portion of the flow chart belonging to the second embodiment of the invention. The flowchart is considered to have an executive portion by which various functions of the microprocessor 13 are programmed. The instructions implementing the invention are executed by the processor 15 at regularly scheduled pre-determined test intervals, 10 minutes to be exact in the embodiments of this invention. For convenience, a legend for the Figures is listed below, which identifies the various abbreviations of the arithmetic values used to implement the invention to achieve accurate RST. The portion of the flow chart illustrated in Figures 4B, 4C and 4D has a single stage of that executive routine illustrated as decision element 31. The terms of the legend are OTI is occupancy time, OTE is occupancy temperature, PT is current time of the day, ART is current recovery time, CT is the current temperature, TD is the time difference, RD is the ramp delta, RSP is the ramp reference point, RRX is ramp speed, RRX + i is new ramp speed, m, n are positive integers, T0 is control band shift, RST is recovery start time, Ts ,? is the space temperature detected at event 1, Ts, 2 is the space temperature detected at event 2, Toa is the external temperature, (RR2) is recovery ramp speed optimized (revised / updated for recovery period AM or Present PM, and (RRX) is current or estimated recovery ramp speed of the previous AM or PM recovery period corresponding to the AM or PM recovery period present (ie corresponding to (RR) 2). to discuss briefly before explaining the operation of Figures 4A, 4B, 4C and 4D.There may be considered the time between a time lapse to the reference value and the specified OTI having two different periods.This is the period of initial low energy when CT is controlled at the temperature that requires less energy This is followed by the recovery period where the control unit 27 brings the controlled space back to the OTI. With the flow chart of Figures 4A and 4B there is a recovery flag that is placed by instructions in the program at the start of the recovery period and releases when the recovery is complete. It is considered that the recovery flag has been initialized to its released condition at the beginning of each period of return to the reference value. In the method explained in connection with the flow chart of Figure 4A, there is a check flag that is adjusted by instructions in the program at the start of a plant "ON" cycle and releases when the plant is "OFF". It is considered that the verification flag has been initialized to the condition released at the beginning of each plant "ON" period. Figure 2 shows space-time temperature of the thermostat 12 of the present invention in a heating mode, where the current day is colder than a previous day. The temperature level 88 is the reference point temperature back to the reference value. Line 83 is the drop in temperature with respect to time. Line 85 is (dTs / dt) 2 of equation (10) time 91 is the stage of change in temperature control reference point from the value returned to the reference value to the comfort value. The dark line 92 is the space temperature if a related technical approach is used where the reference point temperature is maintained for longer than it should be on a colder, sloping day. Line 87 is the expected space temperature recovery rate as in the related art. Line 90 is the scheduled change or occupancy time. Line 89 is the occupancy temperature or comfort reference point. Line 86 is the ramp rate (dT? / Dt) x as in the related art, based on a previous recovery if there is no adaptation according to the present invention. The duration of time 93 is later recovery if a related technique is used when the previous day was hotter than the present day. The duration of time 94 shows a prior time by which recovery is initiated in advance to achieve the comfort set point temperature by time 90 since the change of a colder day is anticipated by the present invention according to the equation (10) Figure 3 shows space-time temperature of the thermostat 12 of the present invention in a heating mode, where the current day is hotter than a previous day. The temperature level 88 is the reference point temperature back to the reference value and the line 89 indicates the occupancy temperature or comfort set point. Line 83 shows the fall in space temperature when the plant or furnace is OFF. Line 95 is the ramp rate (dTß / dt) 2 as in the related art, based on a prior recovery if there is no optimization according to the present invention. Line 90 is the occupancy time or programmed range when the comfort temperature level is to be achieved. Line 96 is the ramp rate (dTs / dt) 2 from equation (10) of the present invention which takes into consideration that the current day is hotter than the previous day. Line 97 is the recovery speed of space temperature expected as in the related art. The period of time 98 is the duration of the previous recovery if the approach of the related art is used when the previous day was colder than the present day. The time period 99 is the duration by which the recovery is retarded by using the present invention in view of the equation (10) where the current day is hotter than the previous day. In Figure 4A, the decision block 31 compares the current plant status to the state of the plant during the most previous step. If this plant status has changed, then decision block 32 runs to check if the plant status has changed from "DISCONNECTED" during the previous step to "ON". If the plant has just "turned ON", then the difference between the running space temperature and the outside air temperature is calculated in the arithmetic element 33 and stored in the operand memory 16. Next, the element 34 stores in places of operand memory 16 both the current space temperature and the current time of day. The check flag is adjusted by the element 35 and the program flow control is returned to the executive. If the decision block 31 indicates that the plant status has not changed (that is, the new plant status is the same as the old plant state) since the previous step, then the status of the verification flag is checked by decision block 36. If the check flag is adjusted, then the program flow control is returned to the executive. If the check flag is not adjusted, then the program flow control is diverted to the decision block 40. If the response of the decision block 32 is no, then the element 37 stores in memory sites of operand 16, both the current space temperature as the current time of day. The arithmetic element 38 calculates and stores in the operand memory 16 the rate of change in time of the space temperature during the "ON" cycle in the most recently completed plant, and also calculates and stores in the memory of operand 16, the constant thermal-time of the system during the same "ON" cycle. The speed of change and time in the space temperature is represented by a slope of a straight line plot of temperature against time. Mathematically, this is the ratio of the difference between the space temperature at the beginning and end of the "ON" period in the most recent plant to the time duration of this "ON" period. The applicable equation is illustrated in block 38 of Figure 4A. The element 38 also calculates the thermal-time constant of the system as the ratio of the temperature difference from the block 33, to the newly calculated value of the speed of change in time of the space temperature. The check flag is then released in element 39. If the current test interval, as established by the executive has not elapsed, then control is returned to the executive of block 40 as illustrated by the flow path labeled NO. When the test interval ends, then the execution of the instructions comprising the decision element 40 causes the execution of instructions to follow the path labeled YES to a second decision element 42 whose instructions prove the condition of the recovery flag. If the recovery flag is set, the execution of instructions follows the branch labeled ADJUSTED (SET) and begins with the instruction sequence in connector B, either in Figure 4C of the first mode or in Figure 4D of the second mode. If the recovery flag is not adjusted, the execution continues on the branch NOT ADJUSTED (NOT SET) to the arithmetic element 44 that starts the method to determine RST. The instructions of the element 44 first calculate and store in the memory of operand 16, the difference between the current space temperature (CT) and the ambient air temperature (TO?). The element 44 then calculates and stores in the operand memory 16, the recovery ramp rate to be used for the next recovery period (RR) 2. The applicable equation is illustrated in block 44 of Figure 4A. The time difference TD = OTI - PT, where PT is the present time and OTI is the occupation time, is also calculated and stored in a memory location of operand 16. The instructions of element 44 then calculate a delta value ramp RD = TD x (RR) 2 and store RD in an operand memory location 16. The instructions represented by the decision element 46 test the mode signal in the path 24 of Figure 1, to determine whether the thermostat operation is in heating or cooling mode. If it is in cooling mode, the instruction execution follows the path of connector A to Figure 4D. If it is in the heating mode, then the instructions of the arithmetic element 50 are executed to determine a ramp reference value value RSP = OTE-RD. The instructions of the decision element 52 are then executed to make the comparison: current space temperature CT <; RSP. If true, then the instructions of the element 54 are executed to cause an operation signal to be placed in the path 20. With the mode switch 25 that connects the path 20 to the furnace 28, the operation signal causes the furnace 28 operate and start to heat the controlled space 10. The instructions of the element 55 then calculate and store in the memory of operand 16 the difference between the current space temperature and the outdoor air temperature. Both the current space temperature and the current time of day (ie recovery start time) are stored in operand memory 16 by the instructions of element 56. The instructions of element 57 then follow to adjust the recovery flag. The logical flow of the program is then returned to the executive.

The portion of program instructions executed when the thermostat 12 is in the cooling mode to begin recovery, is represented by flow diagram elements of Figure 4B beginning with the connector A. When the test of the decision element 46 detects cooling mode, then all the instructions of elements 60 below are executed to perform a calculation similar to that of element 50, but in the case of element 60 RSP = OTE + RD. Decision element 62 returns to execution to the executive if CT > RSP is not true, and the instruction of element 64 is true. The operating signal generated by the instructions of the element 64 is carried out through the switch 25 to the air conditioning unit 29, which begins to cool the controlled space 10. The arithmetic element 65 calculates the difference between the space temperature current and the outside air temperature and stores it in operand memory 16. Both the current space temperature and the current time of the day (i.e. the recovery start time) are stored in operand memory 16 by the instructions of block 66. The instructions in item 67 adjust the recovery flag and execution then returns to the executive routine. That completes the execution activities and instructions regarding the recovery of the start.

An important feature of this invention is the ability to update the ramp rate (RR) to correct the selection of i presicion of the RST and to take into account any changes in the recovery ramp speed due to changes in air temperature external, internal and / or solar charges, wind direction speed and so on. After the recovery flag has been adjusted by the instructions of any element 57 or 67 and thus during recovery, the instructions of the decision element 42 will transfer execution to the instructions starting from the decision element 70. First the operating mode is test and execution branches either to the instructions of the decision element 72 (cooling condition) or element 78 (heating). It can be noted that as CT falls during a return to a lower OTE from a temperature back to the upper reference value during cooling or as CT increases during a return to a higher OTE from a temperature back to the lower reference value during heating, the CT value will eventually reach a temperature close to the OTE value at which recovery is considered complete. In the heating situation, this value is OTE -TQ where TQ is a control band (which may resemble a hysteresis type) displaced from the OTE. At this point, the temperature control is returned to the temperature control method and continues in the usual way. Similarly, in the cooling situation, this value is 0TE + To. In the first mode, T0 = -16.9 ° C (1.5 ° F) when the tests of elements 72 and 78 show that CT has reached the range of displacement (which turns out to be a single time for each recovery interval), the speed ramp is corrected either by executing the instructions of any element 74 or 80 of Figure 4C in the case of the first embodiment of this invention, or by executing the instructions of any of the elements 75 or 81 of Figure 4D in the case of the second embodiment of this invention. In the first embodiment of this invention, the element 80 (Figure 4C) represents instructions that calculate an updated ramp rate (RR) lf in the heating condition and then replace the value in the location in the memory of operand 16, where (RR) X is stored with the new ramp speed value. Also in the first embodiment of this invention, the element 74 (Figure 4C) represents instructions that calculate an updated ramp rate (RR) X / in the cooling situation and then replace the value in the location in the memory of operand 16 in where (RR) X is stored with the new ramp speed value. It should be noted that the instructions for both elements 74 and 80 in Figure 4C are identical. Since the instructions of elements 74 and 80 are executed relatively quickly after the conditions of elements 72 and 78, respectively, are satisfied, the OTI-PT factor is the lost time, a value that is very close to the error in the most recent RST. In the second embodiment of this invention, the element 81 (in Figure 4D) represents instructions that calculate an updated ramp rate (RR) i + 1 = RRX / + (OTI - PT) / 2B in the heating condition and then replaces the value in the location in the memory of operand 16 where (RR)? is stored with the new ramp speed value RR + ?. RRX is the ramp speed value used during the pre-determination of RST. Since the instructions for element 81 are executed relatively quickly after the condition of element 78 is satisfied, the factor OTI - PT is the lost time, a value that is very close to the error in the most recent RST, and may already be positive or negative. It is intended that the expression 2"implies that the lost time is multiplied by the inverse of two raised to a positive whole power, in the first mode m = 5, and 2s = 32 for the specific situation where the temperature is measured in degrees F and time is measured for purposes of this method in increments of 10 minutes.The value of the multiplier for the time lost depends on the selection of these units, and it must be chosen in the heating situation, independently of the units involved, for correct the ramp speed enough to make the lost time approximately 10% to 40% smaller, if the conditions do not change for the same recovery the next day An attempt to correct the ramp speed using a lost time multiplier too large may result in the method becoming unstable to choose RST.A multiplier value in the approximate range of 1/15 to 1/60 is suitable for these units, so that m between 4 and 6 inclusive is preferred. For a ramp rate with units of degrees F / minutes and one-minute test intervals, the closest power of two corresponding to a = 5 is m = 12 and it is likely that m = 11 and m = 13 are also suitable. In situations where the ramp speed has units of degrees F / hour, = 0 that is to say 2"= 1. For the case of the second embodiment of this invention, the selection of the multiplier of time lost as a power of two is convenient for the low end processors used in thermostats because most of them do not have an arithmetic division instruction, being the facility to divide or multiply by a power of two with an attractive simple binary register offset. Power of microprocessors will provide good faith division instructions in them before long, and it will be understood that the use of a power between two as a multiplier of the time lost to update the ramp speed, is strictly a matter of convenience for the second mode In the case of cooling for element 75 (Figure 4D) For the second embodiment of this invention, a calculation similar to that of the element 81 is performed by which the ramp rate (RR) i is updated. However, it has been the experience of the applicant that generally the multiplier of the lost time must be smaller in the cooling mode such that n between 6 and 8 inclusive is the convenient range with n = 7 and l / 2n = 1/128 as the value that is currently preferred. A smaller multiplier is preferred here due to the much smaller slope of the recovery speed when in cooling mode. After the ramp rate has been updated, the current thermal-time constant tx during the "recovery period about to complete" is calculated in element 82, the ratio of the difference between the space temperature at the start of recovery and ambient air temperature also at the start of recovery (either element 55 of Figure 4A for the heating mode or element 65 of Figure 4B for the cooling mode) at the ramp rate (RR) X for the period of recovery period to complete (either of any element 74 of Figure 4C) for cooling or element 80 of Figure 4C (for heating) for the first embodiment of this invention or element 75 of the Figure 4D (for cooling) or element 81 of Figure 4D (for heating) for the second embodiment of the present invention. The current thermal-time constant (tx) is also stored in operand memory 16 by the instructions of element 82. Now that the recovery procedure is completed, and the recovery flag is released by the instructions of element 84. Execution of the instructions of element 84 concludes the performance of the method of the invention and the instruction execution returns to the instructions comprising the executive portion of the program.

Claims (11)

1. CLAIMS 1.- A thermostat system in a space that has a current space temperature, which changes to an occupation temperature, is achieved at a time of occupation, the change of the current space temperature caused by a heater or cooler, which has a recovery start time that occurs at a recovery time before the occupancy time, the recovery time is a period of time required for the current space temperature is changed to the occupation temperature, the recovery time determined by an optimized recovery ramp speed of a certain amount of space temperature change per unit of time, comprising: a first temperature sensor for detecting the current space temperature; a second temperature detector to detect the external ambient air current but close to the space; a processor, connected to the first and second temperature detectors having a memory, instruction processor and a synchronizer; a unit for changing space temperature having a heater and a cooler; and a heating and cooling mode selector connected to the processor and the space temperature change unit #fy where: the recovery start time is at the beginning of a recovery time period before the occupancy time, when the current space temperature will be approximately the same as the occupation temperature, the recovery time is determined by a recovery ramp speed of a certain amount of temperature change per unit time; and the recovery ramp rate is based on (1) a difference between the current space temperature and the outside ambient temperature current at the time of recovery start, (2) a thermal-time constant based on a ratio of a difference in average temperature between the current space temperature and the outside ambient temperature current during the recovery time when the space temperature is changed to be approximately the same as the recovery temperature, and of a time change temperature of the current space temperature during the recovery time, (3) a thermal-time constant for a previous period of a recovery time that has a similar time of day, and (4) a recovery ramp speed for the previous period of recovery that has a similar hour of the day.
2. 2. The thermostat system according to claim 1, wherein the processor can: receive and store outside air and space temperatures of the first and second temperature detectors respectively; sending signals to the unit for changing room temperature to effect or not effect a change in the current space temperature during a recovery time; calculate and store recovery ramp speeds and thermal-time constants; determine and initiate a recovery start time; calculate and implement a recovery ramp speed; and determining a recovery start time such that the end of a recovery time coincides wryly with the occupancy time, when the current space temperature becomes approximately the same as the occupation temperature.
3. 3.- A method to optimize a temperature recovery ramp speed of a thermostat that has temperature detectors of current space and outside temperature, a processor, connected to the temperature detectors, to calculate and compare the information, to record and accessing information to and from an operand memory connected to the processor, for recording time from a clock connected to the processor, and for issuing operation signals, in a space having a space temperature that is controlled with respect to a fixed recovery temperature, and occupancy times, which includes: recording by the processor in the operand memory, space temperatures and outside temperatures; adjusting and recording in the operand memory, at least at an occupation temperature and an occupancy time following a temperature range back to the reference value; record in the operand memory a current hour of the day; calculate and record a ramp speed in the operand memory; calculate and record in the operating memory thermal constants-time of a current recovery period, and a similar previous recovery period (AM or PM) during a period of "on" of plant, where a plant changes space temperature to approaching the occupation temperature; calculate and record in the operand memory, differences between space temperatures and corresponding outside air temperatures; calculating and recording in the operand memory a rate of change in time of the space temperature during the "on" period in the plant; calculate and record in the operand memory a rate of change in time of the space temperature during each recovery period for the day; calculate an updated recovery ramp rate equal to a product of a temperature recovery ramp speed for the similar pre-recovery period (AM or PM) and a temperature difference speed between space temperature and air temperature outside at the beginning of the current recovery period at a temperature difference between the space temperature and the ambient air temperature at the start of the similar pre-recovery period (AM or PM) and the ratio of the thermal constant-time for the period of similar pre-recovery (AM or PM) to the thermal-time constant for the current recovery period and store the product as the recovery ramp speed for the current recovery period at a location in the operand memory: at the end of the Pre-determined length intervals, calculate a time difference equal to the difference between the occupation time and the present time and record the time difference in the operand memory; after a time difference has been recorded, calculate and record in the operand memory a delta ramp equal to a product of the most recent recorded time difference and the ramp rate; calculating and recording in the operand memory a ramp reference point equal to at least one of the differences between the occupation temperature and the ramp delta and the sum of the occupation temperature and the ramp delta; and comparing the ramp reference point with the space temperature and setting a selectable ratio between the ramp reference point and the space temperature exists, issuing an operation signal to "turn on" or "turn off" the plant.
4. 4. A system to optimize a ramp speed after a return to the reference value in a space and time temperature, and adjust a temperature and occupancy time that has a recovery period where the space temperature is changed by a plant that heats or cools, at the occupation temperature to the occupation time, the plant is controlled by a thermostat that has external temperature and space detectors, with heating and cooling modes that a processor has to execute instructions stored with a program and that have an executive to program the instructions, and with a program flow control, with a memory to store the program and calculate results, with a clock to provide the present time of the day, the program has set a recovery flag to Start of the temperature recovery period and release when the recovery period has been completed and / or at the beginning of each return period to the reference value and the program that has a check flag that is adjusted when the flag is turned on and released when the plant goes off, which comprises: a first decision element that works if it receives a signal from the executive , and determines whether a current on / off state of the plant is the same as a past on / off state of the plant, during a previous step through it and the first decision element sends out either a yes or a no; a second decision element that works if it receives a no from the first decision element, and determines if the plant status has changed from a shutdown during a previous step still on and if so, the second decision element sends out a yes and if not, a no; a first calculation element that works if it receives a yes from the second decision element, and calculates a difference between a current space temperature and an outside temperature and stores the difference in memory, stores the current space temperature and the current time of the day in memory, adjust the check flag and return the program flow to the executive; a third decision element that works if it receives a yes from the first decision element and checks a status of the check flag, if the check flag is adjusted, then the program flow is returned to the executive and if the check flag does not it is adjusted, then the third decision element sends out a non-adjust; a second calculation element that works if it receives a no from the second decision element and stores the current space temperature and the current time of the day in the memory, calculates the rate of change in time of the space temperature after a cycle of more recently completed plant ignition, calculates a thermal constant and a more recently completed plant lighting cycle time, stores the rate of change in time and the thermal-time constant in the memory, and then releases the check flag and sends exit a verification flag; a fourth decision element that works if it receives a non-adjust of the third decision element or release check flag of the second calculation element, and returns the program flow to the executive if it has not completed a test interval and sends out a yes the test interval has ended; a fifth decision element that works if it receives a yes from the fourth decision element and tests a condition of the recovery flag, sends adjustment if the recovery flag is adjusted and sends out does not adjust if the recovery flag is not adjusted; a third calculation element that works if it receives a non-adjust from the fifth decision element and calculates and stores in the memory a difference between the current space temperature and the outside temperature, calculates and stores in memory a recovery ramp rate which is used in a subsequent recovery period, calculates and stores in memory a time difference of the occupation time and the current time of the day, calculates and stores a ramp delta in the memory and sends out a completed calculation signal; a sixth decision element that works if it receives a calculation signal completed from the third calculation element and sends out a cooling signal if the thermostat is in a cooling mode and sends out a heating signal if the thermostat is in a heating mode; a fourth calculation element that works if it receives a heating signal from the sixth decision element and calculates a ramp reference point which is the occupation temperature minus the ramp delta, and then outputs a completed calculation signal; a sixth decision element that works if it receives a calculation signal completed from the fourth calculation element and determines if the current space temperature is less than the ramp reference point and if it is not, it sends out a no and returns the program flow to the executive and, if so, sends out a yes and signals the plant to turn on; and a fifth calculation element that works if the plant is signaled to turn on by the seventh decision element and calculates and stores in the memory a difference between the current space temperature and the outside temperature, stores the current space temperature in the memory and the current time of day, adjust the recovery flag and return program control to the executive.
5. 5. The system according to claim 4, further comprising: a sixth calculation element that works if it receives a cooling signal from the sixth decision element and calculates a ramp reference point that is a sum of the occupation temperature and the ramp delta, and then send out a completed calculation signal; an eighth decision element that works if it receives a completed calculation signal from the sixth calculation element and determines if the current space temperature is greater than the ramp reference point and if not it sends out a no and returns the program flow to the executive, and if so, send out a yes and signal to the plant that turns on; and a sixth calculation element that works if the plant is signaled to turn on by the eighth decision element and calculates and stores in the memory a difference between the current space temperature and the outside temperature, and stores the temperature in the memory current space and the current time of day, adjust the recovery flag and return program control to the executive.
6. 6. The system according to claim 5, which further comprises: a ninth decision element that works if it receives adjustment from the fifth decision element and sends out a cooling signal if the thermostat is in a cooling mode and sends output a heating signal if the thermostat is in a heating mode; a tenth decision element that works if it receives a heating signal from the ninth decision element, and if the current space temperature is not greater than the occupation temperature minus a control band shift, then the program control is returned to the executive and if the current space temperature exceeds the occupancy temperature minus the control band shift, then it outputs an if; an eighth calculation element that works if a si of the tenth decision element is received, and calculates and stores an updated ramp rate in the memory and outputs a completed calculation signal; an eleventh decision element that works if it receives a cool signal from the ninth decision element and if the current space temperature is not less than the occupation temperature plus a control band shift then the program control is returned to the executive and if the current space temperature is less than the occupation temperature plus the control band shift then it outputs an if; a ninth calculation element that works if it receives a si from the eleventh decision element and calculates and stores an updated ramp rate in the memory and sends out a completed calculation signal; and a tenth calculation element that works if it receives a completed calculation signal from the eighth or ninth calculation element and calculates and stores in memory a thermal-time constant that is a ratio of the difference of space and exterior temperatures to a recovery period start of the ramp speed for the recovery period to be completed, releases the recovery flag when the recovery period is complete, and then returns program control to the executive.
7. 7. The system according to claim 6, that the updated ramp rate of the eighth and ninth computing elements is a difference of the space temperature at the start of the recovery period and the current space temperature, divided by a difference of the ramp reference point and the current time of day.
8. 8. The system according to claim 6, that the updated ramp speed is equal to a previous ramp speed plus a difference that is divided by two to the nth power, where the difference is the occupation time minus the current time of the day and n is an integer from 0 to 20.
9. 9. - A thermostat system in a space that has a current space temperature that changes to an occupation temperature, which is achieved at an occupancy time, the change of the current space temperature caused by a heater or cooler, which has a recovery start time that occurs at a recovery time before occupancy time, recovery time is a period of time required for the current space temperature that is changed to the occupation temperature, the recovery time determined by a optimized recovery ramp speed of a certain amount of space temperature change per unit of time, comprising: a first temperature sensor for detecting the current space temperature; a second temperature detector to detect the external ambient air current but close to the space; a processor, connected to the first and second temperature detectors having a memory, instruction processor and a clock; a space temperature changing unit having a heater and a cooler; and a heating and cooling mode selector connected to the processor and the unit for changing room temperature; and where: the recovery start time is at the end of a recovery time period before the occupation time, when the current space temperature will be approximately the same as the occupation temperature, the recovery time is determined by a recovery ramp speed of a certain amount of temperature change per unit time; and the recovery ramp speed is based on (1) a difference between the current space temperature and the outside ambient temperature current at the time of recovery start, (2) a thermal-time constant for the recovery time based on a temperature difference velocity between the current space temperature and the outside ambient temperature during a more recent plant "firing" cycle at a time change rate of the current space temperature, during the "on" cycle of most recent plant; (3) a thermal-time constant for a previous period of a recovery time that has a similar time of day, and (4) a recovery ramp speed for the previous period of recovery that has the same time of day.
10. 10.- A method to optimize a ramp speed of temperature recovery of a thermostat that has temperature detectors of current space and outside temperature, a processor, connected to temperature detectors, to calculate and compare information, to record and access information to and from an operand memory connected to the processor, to record time from a clock connected to the processor, and to issue operation signals, in a space having a temperature of space that is controlled with respect to a fixed recovery temperature and a time of occupation, which includes: recording by the processor in the operand memory, space temperatures and outdoor temperatures; adjusting and recording in the operand memory, at least at an occupation temperature and an occupancy time following a temperature range back to the reference value; record in the operand memory a current hour of the day; calculate and record a ramp speed in the operand memory; calculate and record in the operand memory the thermal-time constant of a current recovery period, and a thermal-time constant for a similar previous recovery period (AM or PM) during a period of "on" of plant, where a room temperature is changed to approach the occupation temperature; calculate and record in the operating memory differences between space temperatures and corresponding outside air temperatures; calculate and record in the operand memory a speed of change in time of the space temperature during the "on" parrot in plant; calculate and record in the operand memory a rate of change in time of the space temperature during each recovery period for the day; and calculating an updated recovery ramp rate equal to a product of the temperature recovery ramp rate determined at the end of the similar pre-recovery period (AM or PM) and a temperature difference ratio between the space temperature and the outside air temperature at the start of the current recovery period at a temperature difference between the room temperature and the ambient air temperature at the start of the similar pre-recovery period (AM or PM) and the ratio of the thermal constant-time to the previous recovery period similar (AM or PM) to the thermal-time constant for the current recovery period and store the product as the recovery ramp speed for the current recovery period at a location in the operand memory.
11. 11. The method according to claim 10, which further comprises: at the end of the pre-determined length intervals, calculate an hour difference equal to the difference between the occupation time and the current time and record the difference in time in operand memory; after a time difference has been recorded, calculate and record in the operand memory a ramp delta equal to a product of the last difference in recorded time and the ramp rate; calculating and recording in the operand memory a ramp reference point equal to at least one of the differences between the occupation temperature and the ramp delta and the sum of the occupation temperature and the ramp delta; and comparing the ramp reference point with the space temperature and when a there is a selectable relation between the ramp reference point and the space temperature, issue an operation signal to "turn on" or "turn off" the plant. SUMMARY OF THE INVENTION An adaptive recovery method for a thermostat back to the reference value, which uses the intersection of the space temperature with an inclined recovery temperature line approaching the change in temperature, as a function of time during recovery of the temperature controlled space from a temperature returned to the reference value, to determine the time in which recovery to the recovery temperature will begin. The thermostat begins recovery when a current space temperature crosses the recovery temperature line. A useful feature of the apparatus and method implementing the invention constantly calculates and updates the slope of the temperature recovery line. The update of the slope of the temperature recovery line is based on lost time, ie the time between currently achieving the next desired reference point temperature and the next reference point time associated with the next reference point temperature , the space temperature, the outside air temperature, the ramp rate of temperature recovery during the previous recovery period and the current and past thermal-time constants. If the heating or cooling load in the space changes, the current space temperature will cross the recovery temperature line at a different time, causing the recovery to begin at a time more compatible with the heating load and current cooling in order to recover fully at or near the desired time. Variables can be added to the system. HS / frp / 23 / PCT-118