A thermostat for includes a processing circuit configured to operate the building equipment to control an environmental condition within a building including a first zone and second zones and receive a first time-series data set for a parameter of a first piece of the building equipment associated with the first zone. The processing circuit is configured to receive second time-series data sets for the parameter of second pieces of building equipment associated with the second zones. The processing circuit is configured to perform a comparison including comparing the first time-series data set with the second time-series data sets and generate recommendations for improving the performance of the first piece of building equipment based on the comparison of the first time-series data set with the second time-series data sets.

One illustrative device includes, among other things, an active device comprising a first terminal, a first bias resistor connected to the first terminal, and a first resistor comprising a first phase transition material connected in parallel with the first bias transistor, wherein the first phase transition material exhibits a first low conductivity phase for temperatures less than a first phase transition temperature and a first high conductivity phase for temperatures greater than the first phase transition temperature.

The present invention provides a heater temperature control circuit including a heater and a control circuit that controls a temperature of the heater, wherein the control circuit includes a bridge circuit in which a first circuit and a second circuit are connected in parallel, and an operational amplifier connected to the bridge circuit, wherein in the first circuit, the heater and a resistor are connected in series, and a midpoint of the first circuit is connected to one input portion of the operational amplifier, and an output value V.sub.out from the second circuit is input to the other input portion of the operational amplifier, the output value V.sub.out being obtained by multiplying a division ratio of a target resistance value R.sub.h of the heater and a resistance value R.sub.1 of the resistor with a reference voltage V.sub.ref of the bridge circuit.

One illustrative device includes, among other things, an active device comprising a first terminal, a first bias resistor connected to the first terminal, and a first resistor comprising a first phase transition material connected in parallel with the first bias transistor, wherein the first phase transition material exhibits a first low conductivity phase for temperatures less than a first phase transition temperature and a first high conductivity phase for temperatures greater than the first phase transition temperature.

A heater control system is disclosed. In an embodiment, the heater control system includes a fluid heater that includes a heating element. The heating element controlled by a switch. The heater control system also includes a controller that can operate the switch. The controller is configured to determine whether a temperature associated with the fluid heater is below a predetermined temperature threshold. The controller causes the switch to transition to an operational state when the temperature is below the predetermined temperature threshold allowing current to flow through the at least one heating element.

A heating apparatus includes: first and second heaters, first and second switches, first and second ramp signal generation circuits, a signal processor circuit, first and second comparison circuits, and a switch control circuit. The first and second ramp signal generation circuits generate first and second ramp signals according to first and second output currents, respectively. The signal processor circuit senses a temperature to generate a temperature-related signal. The first and second comparison circuits compare the first and second ramp signals with the temperature-related signal, to generate a first PWM signal and a second PWM signal for controlling the first and second switches respectively, to determine the first and second output currents so that there is a predetermined ratio between average powers of the first heater and the second heater.

A thermostat for includes a processing circuit configured to operate the building equipment to control an environmental condition within a building including a first zone and second zones and receive a first time-series data set for a parameter of a first piece of the building equipment associated with the first zone. The processing circuit is configured to receive second time-series data sets for the parameter of second pieces of building equipment associated with the second zones. The processing circuit is configured to perform a comparison including comparing the first time-series data set with the second time-series data sets and generate recommendations for improving the performance of the first piece of building equipment based on the comparison of the first time-series data set with the second time-series data sets.

In a general aspect, a circuit can include a first resistor configured to be coupled to a first terminal of a temperature-sensitive resistance, a second resistor configured to be coupled to a second terminal of the temperature-sensitive resistance and a temperature information circuit. The temperature information circuit can be configured to: receive a first voltage from the first terminal of the temperature-sensitive resistance; receive a second voltage from the second terminal of the temperature-sensitive resistance; and provide temperature information based on the first voltage and the second voltage. The temperature information circuit can include a first comparison circuit configured to determine a difference between the first voltage and the second voltage, and a second comparison circuit configured to compare an output of the first comparison circuit to a reference.

When a voltage signal is input to input terminals as a positive voltage, the voltage conversion circuit generates a control voltage proportional to an input voltage by a voltage-dividing circuit according to resistance elements, a voltage follower circuit according to an operational amplifier, and a voltage-dividing circuit according to resistance elements. When a voltage signal is input to the input terminals as a negative voltage, since the operational amplifier outputs a power supply voltage according to an input of the negative voltage, the voltage conversion circuit generates a predetermined positive voltage obtained by dividing the power supply voltage by the resistance elements as the control voltage. The predetermined positive voltage is higher than a voltage range of the control voltage when the voltage signal is input as the positive voltage.

A temperature control system including an electrical relay system, a thermistor, a normally open/normally closed digital thermostat, a parallel-circuit, and a series-circuit, with each of the parallel-circuit and the series-circuit electrically coupled to a refrigeration system. The parallel-circuit is electrically coupled to a relay and a cooling system and the relay-coil is in electrical communication and controlled via the thermostat. Also, the thermostat is in electrical communication with the thermistor. The temperature control system is configured to operate both the parallel-circuit and the series-circuit simultaneously while the temperature is above a first-set-point, and temperature control system, via the relay assembly, and cuts current flow to the parallel-circuit when the temperature is at or below the second-set-point, configured to reduce a wattage supplied and therefore a speed of fan motors of the evaporative refrigeration system to conserve power usage.