US 4,228,511 A · System and method of power demand limiting and temperature control

Abstract

A room thermostatic control providing for automatic power defer, i.e. modification of load consumption of electrically energized heating and cooling systems during intervals when there is a peak load demand on the electrical supply system. During power defer ambient indoor temperature is controlled by set point adjustment to minimize discomfort, e.g. by pre-boosting, by ramped temperature deferral at controlled rates, and thereafter by ramped recovery at controlled rates to the reference, i.e. desired, temperature. The preferred embodiment has normal and night set back reference temperature potentiometers and ambient indoor temperature sensing circuits providing, respectively, analog reference and analog indoor signals. Digital set point signals are derived and compared with the analog indoor signal to actuate relays controlling operation of the heating and cooling means, e.g. compressor and auxiliary resistance heating. A circuit sensing external conditions, e.g. outdoor temperature, indicative of power defer, is utilized to generate a power defer signal for enabling modification of the set point. In the preferred embodiment digital signals are stored for each of a plurality of consecutive real time intervals for heating and cooling modes. A real time clock is utilized to access the digital signals for the current time interval. During presence of a power defer signal set point variation is controlled in accordance to the relevant digital signals for each current time interval.

Claims33

Dependent claims

A thermostatic control for use in controlling indoor temperature within a structure and for selectively reducing electrical energy consumption of ambient temperature conditioning means during intervals of peak load demand on the electrical system, comprising:

(a) user adjustable reference temperature selection means for selecting a desired reference temperature and first means for deriving therefrom a temperature set point value;
(b) second means responsive to a signal condition indicative of an imminent electric power peak demand for generating a power defer signal;
(c) third means responsive to said power defer signal for automatically ramping said temperature set point value during actual peak load demand in a defer direction at a predetermined rate to increase electrical energization of the ambient temperature conditioning means to ramp indoor ambient temperature in a defer direction from the desired reference temperature;
(d) means responsive to termination of actual peak load demand for automatically ramping said temperature set point value at a predetermined rate to increase energization of the ambient temperature conditioning means until said temperature set point value returns to the value of the temperature set point derived from said reference temperature selection means;
(e) fourth means for deriving a signal representative of indoor ambient temperature value;
(f) fifth means responsive to signals representative of said indoor ambient temperature value and said temperature set point value of generating a control signal;
and
(g) sixth means responsive to said control signal and adapted for connection to the ambient temperature conditioning means to modify operation of the last named means.

5 more elements

A room thermostatic control for use in controlling indoor temperature within a structure and for selectively reducing electrical energy consumption of ambient temperature conditioning means during intervals of peak load demand on the electrical system, comprising:

(a) user adjustable reference temperature selection means for selecting a desired reference temperature and first means for deriving therefrom a temperature set point value;
(b) second means for generating a power defer signal responsive to a signal condition, indicative of an imminent electric power peak demand and supplied from a location external of the thermostatic control and the structure being conditioned by ambient temperature conditioning means;
(c) third means responsive to said power defer signal for automatically ramping said temperature set point value in a first boosting direction to increase energization of the ambient temperature conditioning means, and subsequently ramping said temperature set point value in a second defer direction to decrease electrical energization of the ambient temperature conditioning means, whereby indoor ambient temperature is offset in a boost direction from the desired reference temperature and during actual peak load demand is ramped in a defer direction from the desired reference temperature;
(d) fourth means for deriving a signal representative of indoor ambient temperature value;
(e) fifth means responsive to signals representative of said indoor ambient temperature value and said temperature set point value for generating a control signal;
and
(f) sixth means responsive to said control signal and adapted for connection to the ambient temperature conditioning means to modify operation of the last named means.

4 more elements

An indoor thermostatic control assembly adapted for location in a building for controlling electrically energized ambient temperature conditioning means, such as heat pump systems, to maintain ambient indoor temperature within a building and power defer operation for selectively reducing electrical energy consumption of said conditioning means during time intervals of peak demand on the electrical supply system energizing said conditioning means, comprising:

(a) indoor temperature sensing means providing a first electrical signal having a value representative of actual ambient indoor temperature;
(b) temperature reference means for user selection of a desired ambient temperature and providing a second electrical signal of value representative of said desired ambient temperature;
(c) set point selection means for deriving a temperature set point signal from said second signal;
(d) signal storage means storing a block of digital signals for each of a plurality of contiguous time intervals, the block for each time interval defining any ramping of said set point signal desired to be performed during power defer operation occurring during such interval;
(e) power defer signal means for producing a power defer signal responsive to a signal condition occurring external of the building which condition is indicative of the need for power defer operation;
(f) digital real time clock means for consecutively selecting the block of digital signal applicable to the current real time increment;
(g) digital ramping means for incrementally ramping the digital value of said temperature set point signal in accordance to said selected block of digital signals upon occurrence of said power defer signal;
(h) comparison means for comparing the thus modified set point signal and said first electrical signal;
(i) means responsive to said comparison for producing a control signal adapted to actuate ambient temperature condition means, whereby during power defer operation the ambient temperature is gradually variable in respect to the desired ambient temperature at rates controlled by said outdoor thermostatic control assembly.

6 more elements

In a room thermostatic control for mounting in a building and incorporating temperature sensing means providing an ambient indoor temperature signal, and operator adjustable means providing a reference temperature signal indicative of desired indoor temperature and output means responsive to comparison of signals derived therefrom to produce output signals for controlling electrical energization of ambient temperature conditioning means, first and second memory storage portions and a real time clock, a power deferral method of reducing electrical consumption of the conditioning means during intervals of peak load demand on the system supplying electrical energization, comprising the steps of:

(a) deriving a set point temperature value representative of the value of said reference temperature signal and storing said set point temperature value in a first memory storage portion;
(b) accessing a second memory storage portion containing stored digital signals for each of a plurality of consecutive real time increments, the stored digital signals for selected ones of said consecutive time increments containing an enabling signal for ramping said set point temperature signal during the presence of a power deferal signal;
(c) under control of a real time clock continuously selecting the stored digital signals of the currently effective time increment;
(d) responsive to the simultaneous presence of the power defer signal and of said enabling signal during the currently effective time increment, incrementally ramping the value of the stored set point signal in a first direction to gradually decrease energization of ambient temperature control means at the first predetermined rate;
(e) responsive to termination of either of said power defer signal or of said enabling signal during the currently effective time increment, terminating said incremental ramping in the first direction and commencing incremental ramping of the stored set point signal in an opposite, second, direction to gradually increase energization of the ambient temperature control means, whereby the ambient indoor temperature returns to the value representative of said reference temperature signal;
and
(f) producing output signals responsive to comparison of the set point temperature signal and of the ambient indoor temperature signal for modifying the actuation of the ambient temperature conditioning means.

4 more elements

A room thermostatic control for use in controlling indoor temperature within a structure and for selectively reducing electrical energy consumption of ambient temperature conditioning means during intervals of anticipated peak load demand on the electrical system, comprising:

(a) user adjustable reference temperature selection means providing an analog reference temperature signal of value representative of desired indoor ambient temperature;
(b) indoor ambient temperature sensing means for providing an analog ambient indoor temperature signal;
(c) comparison means comprising a plurality of inputs and an output;
(d) analog control means comprising an output coupled to one input of the comparison means, and inputs connected for sequential coupling of said analog reference signal and of said analog ambient indoor temperature signal to said output;
(e) digital storage means for storing one of the aforesaid analog signals in digital form as a digital temperature signal;
(f) digital to analog conversion means comprising an input and an output coupled to another input of said comparison means;
(g) digital processing means for sequentially coupling the stored digital temperature signal to an input of said digital to analog conversion means and for controlling the simultaneous coupling of said one of the aforesaid analog signals to the one input of said comparison means;
(h) said digital processing means being responsive to the output of said comparison means for sequentially updating the value of said stored digital temperature signal to correspond to the current value of said one of the aforesaid analog signals;
(i) means for deriving a digital set point temperature value from said stored digital signal and for storing said digital set point value;
(j) means responsive to a signal condition indicative of an imminent electrical peak power demand for producing a power defer signal;
(k) means responsive to said power defer signal for modifying the stored digital set point value;
and
(l) means responsive to comparison of the values of the other one of the aforesaid analog signals and of said stored digital set point value for producing a control signal adapted to modify actuation of the ambient temperature conditioning means.

10 more elements

Dependencies are inferred from the claim text.

System and method of power demand limiting and temperature control

Life of this patent

System and method of power demand limiting and temperature control

Life of this patent

Abstract

Claims33