System and method for switching-over between heating and cooling modes

An apparatus for controlling equipment having a heating mode and a cooling mode of operation for conditioning a physical space, the apparatus comprising:

• a microcontroller configured to control operation of the equipment;
• a first input configured to receive a setpoint temperature;
• a second input configured to receive a temperature of the physical space;
• a first timer configured to measure a first time period associated with the length of time since an operating mode of the equipment has been switched;
• a comparator configured to:
• compare the received temperature with a first threshold temperature, if the equipment is in a heating mode, and
• compare the received with a second threshold temperature, if the equipment is in a cooling mode;
• and
• a first output configured to:
• signal the equipment to switch from the heating mode to the cooling mode, if the received temperature has remained above the first threshold temperature for at least a second time period and the first time period exceeds or equals a predetermined time period, and
• signal the equipment to switch from the cooling mode to the heating mode, if the received temperature has remained below the second threshold temperature for at least a third time period and the first time period exceeds or equals the predetermined time period.

A method for maintaining a room temperature in a tolerance band around a setpoint temperature, the method comprising the steps of:

• sensing the room temperature;
• maintaining a mode-switching time value relating to a first time period since an operating mode of conditioning equipment has changed, wherein the conditioning equipment has a cooling mode and a heating mode of operation for affecting the temperature of the room;
• if the equipment is in the heating mode of operation, then:
• switching the equipment to the cooling mode if the sensed room temperature has remained above a first threshold temperature for a first predetermined length of time and the mode-switching time value indicates that the first time period is greater than or equal to a second predetermined length of time, wherein the first threshold temperature is greater than the setpoint temperature, and
• initiating a cooling algorithm, said cooling algorithm controlling operation of the equipment when in the cooling mode;
• and
• if the equipment is in the cooling mode of operation, then:
• switching the equipment to the heating mode if the sensed room temperature has remained below or equal to a second threshold temperature for the first predetermined length of time and the mode-switching time value indicates that the first time period is greater than or equal to the second predetermined length of time, wherein the second threshold temperature is less than the setpoint temperature, and
• initiating a heating algorithm, said heating algorithm controlling operation of the equipment when in the heating mode.

A method for controlling equipment that includes a heating and a cooling mode of operation to condition the temperature of a room, the method comprising the steps of:

• (a) obtaining a setpoint temperature for the room;
• (b) periodically sensing the ambient temperature of the room, wherein a series of ambient temperatures are sensed;
• (c) determining a series of differences by subtracting the setpoint temperature from each sensed ambient temperature;
• (d) determining if substantially all of a subset of the differences are:
• (d.1) greater than or equal to a first predetermined threshold, if the equipment is in a heating mode, or
• (d.2) less than or equal to a second predetermined threshold, if the equipment is in a cooling mode,
• wherein the subset includes those differences relating to the ambient temperatures sensed during a first time period;
• (e) determining if a second time period has elapsed since the equipment has changed between modes of operation;
• (f) if the second time period has elapsed and substantially all of the subset of differences are determined to be greater than or equal to the first predetermined threshold, then generating a first control signal for switching the equipment to the cooling mode;
• and
• (g) if the second time period has elapsed and substantially all of the subset of differences are determined to be less than or equal to the second predetermined threshold, then generating a second control signal for switching the equipment to the heating mode.