Abstract: A method for heating and cooling building interiors with a boiler and/or chiller of fluid travelling in a closed loop includes temperature transducers located at the inlet and outlet of the boiler and/or chiller. A Variable Frequency Drive pump and closed loop piping for transporting the fluid is necessarily provided. The temperature transducers at the outlet and inlet of the boiler and/or chiller are electrically connected to a PLC or pump logic control device for receiving information from the transducers and altering the speed and/or frequency of operation of the pump or set of circulating pumps to create an ideal temperature differential of about 20 degrees C. between the outlet and the inlet.

Abstract: A system for heating and cooling building interiors with a boiler or chiller of fluid travelling in a closed loop includes a pair of temperature transducers located at the inlet and outlet of the boiler/chiller. A pump and piping for transporting the fluid is provided. The temperature transducers at the entrance and exit of the boiler or chiller are electrically connected to a pump logic control for receiving information from the transducers and altering the speed and/or frequency of operation of the pump or set of circulating pumps to create an ideal temperature differential between the two transducers that will maximize the efficiency of the boiler or chiller. Preferably, the temperature difference is 20 degrees F. In preferred embodiment, the system will also include one or more variable frequency drive pumps and a pump logic circuit device which will drive the speed by controlling frequency of electricity to the pumps so as to maintain maximum efficiency of electric consumption.

Abstract: The temperature in a water tank (e.g., a residential water tank) is monitored, and a controller switches between a high temperature mode of operation and a low temperature mode of operation (e.g., based on a daily or weekly program). During the low temperature mode of operation, the controller generates signals to selectively activate a water heater to keep the water's temperature within a first range of values, (e.g., between 105 and 113° F). During the high temperature mode of operation, the controller generates signals that cause the water heater to heat the water to a temperature that is above the first range of values. This arrangement may be used for saving energy by operating in the low temperature mode at night and during those parts of the day when nobody is home, and by operating in the high temperature mode in the morning and evening when the demand for hot water is typically high.