Thermostat incorporating thin film carbon dioxide sensor and environmental control system

A system for monitoring and modifying the quality and temperature of air within a conditioned space which includes a damper unit for selectively admitting outside air into the conditioned space, a temperature moderating unit and a control unit, said control unit comprising:

• A) a thermostat including temperature set point establishment means and temperature control means for selectively activating said temperature moderating unit when the temperature of the conditioned space deviates by a predetermined amount from the established temperature set point;
• and
• B) CO2 concentration measuring and control apparatus for the conditioned space, said CO2 concentration measuring and control apparatus comprising:
• 1) a CO2 sensor comprising:
• a) a cathode electrode disposed on a substrate and fabricated from a first metal;
• b) an anode electrode disposed on the substrate spaced from said cathode electrode, said anode electrode being fabricated from a second metal, said first and second metals being selected to have different oxidation-reduction values;
• c) a solid electrolyte disposed on the substrate intermediate and electrically in contact with each of said cathode electrode and said anode electrode such that said cathode electrode, said anode electrode and said solid electrolyte effect a primary electrical cell;
• d) a heater disposed on the substrate;
• e) a heater thermostat disposed on the substrate and connected to said heater and to a source of electrical energy so as to maintain said primary electrical cell within a predetermined temperature range;
• f) said first metal, said second metal and the chemical composition of said electrolyte being further selected such that the voltage established between said cathode and said anode varies in accordance with the CO2 concentration at said primary electrical cell when the temperature of said primary electrical cell is within said predetermined temperature range;
• and
• 2) CO2 concentration modifying apparatus responsive, to the measurement of at least a first voltage level between said cathode and said anode representing a first predetermined CO2 concentration for actuating said damper unit to admit outside air into the conditioned space.

A system for monitoring and modifying the quality and temperature of air within a conditioned space which includes a blower unit, a damper unit for selectively admitting outside air into the conditioned space, a temperature moderating unit and a control unit, said control unit comprising:

• A) a thermostat including temperature set point establishment means and temperature control means for selectively activating said temperature moderating unit when the temperature of the conditioned space deviates by a predetermined amount from the established temperature set point;
• and
• B) CO2 concentration measuring and control apparatus for the conditioned space, said CO2 concentration measuring and control apparatus comprising:
• 1) a CO2 sensor comprising:
• a) a cathode electrode disposed on a substrate and fabricated from a first metal;
• b) an anode electrode disposed on the substrate spaced from said cathode electrode, said anode electrode being fabricated from a second metal, said first and second metals being selected to have different oxidation-reduction values;
• c) a solid electrolyte disposed on the substrate intermediate and electrically in contact with each of said cathode electrode and said anode electrode such that said cathode electrode, said anode electrode and said solid electrolyte effect a primary electrical cell;
• d) a heater disposed on the substrate;
• e) a heater thermostat disposed on the substrate and connected to said heater and to a source of electrical energy so as to maintain said primary electrical cell within a predetermined temperature range;
• f) said first metal, said second metal and the chemical composition of said electrolyte being further selected such that the voltage established between said cathode and said anode varies in accordance with the CO2 concentration at said primary electrical cell when the temperature of said primary electrical cell is within said predetermined temperature range;
• and
• 2) CO2 concentration modifying apparatus:
• a) being responsive to the measurement of at least a first voltage level between said cathode and said anode representing a first predetermined CO2 concentration for turning on said blower unit;
• and
• b) being responsive to the measurement of at least a second voltage level between said cathode and said anode representing a second predetermined CO2 concentration, higher than said first predetermined CO2 concentration, for actuating said damper unit to admit outside air into the conditioned space.

A system for monitoring and modifying the quality and temperature of air within a conditioned space which includes a blower unit, a damper unit for selectively admitting outside air into the conditioned space, a temperature moderating unit and a control unit, said control unit comprising:

• A) a thermostat including temperature set point establishment means and temperature control means for selectively activating said temperature moderating unit when the temperature of the conditioned space deviates by a predetermined amount from the established temperature set point;
• B) CO2 concentration measuring and control apparatus for the conditioned space, said CO2 concentration measuring and control apparatus being integral with said thermostat;
• and
• C) CO2 concentration modifying apparatus:
• 1) being responsive to the measurement by said CO2 concentration measuring and control apparatus of at least a first predetermined CO2 concentration for turning on said blower unit;
• and
• 2) being responsive to the measurement by said CO2 concentration measuring and control apparatus of at least a second predetermined CO2 concentration, higher than said first predetermined CO2 concentration, for actuating said damper unit to admit outside air into the conditioned space.