Abstract: A charging apparatus for an electric storage heater includes a resistance heater in series with a low tariff time switch and a charging switch. While the low tariff time switch is closed, usually at night, an integrator controlled by a differential amplifier controls the charging switch in accordance with the total charge accumulated by the integrator which reflects the use of energy during the preceding day. The charge of the integrator at the end of the day is the result of it being intermittently charged and discharged by a voltage divider circuit which has one or more temperature responsive resistances and transmits a voltage to one input of a differential amplifier for the integrator which can be above or below a reference voltage on the other input of the amplifier.

Abstract: An electric storage heater assembly which includes a core and a resistance heater for the core. A charging switch is in series with the resistance heater and an electric comparator for operating the switch has two inputs connected to first and second controls which are responsive to the instantaneous temperature of the core and the final temperature of the core for the preceding charging period. The first comparator input is also connected to auxiliary controls which sense indoor and outdoor temperatures and provide signals which are summed with the signal which represents the core temperature.

Abstract: The invention relates to a control unit for electric storage heaters which are supplied with energy during low tariff periods and which give up stored energy during high tariff periods. An electronic integrator which is judiciously charged and discharged is used as a control indicator. The integrator is (1) charged to a fixed predetermined value during the high tariff period and (2) discharged starting at the beginning of the low tariff period at a rate inversely proportional to the outdoor temperature. The discharged state of the integrator is sensed and at that time, and for the remainder of the low tariff period, a signal is developed which can be used to actuate a relay to direct electrical energy to storage heaters. If the integrator does not fully discharge during the low tariff period the remaining charge is sensed and a synchronizing circuit is actuated to rapidly remove the charge prior to the start of the high tariff period.

Abstract: An electric storage heater assembly which is charged at night when energy rates are low and utilized during the day when the rates are higher. A fan unit is controlled by a thermostat to extract heat from the heater assembly. The previous days experience relative to the total time the fan operates is a measure of the heat to be stored during the off hours. An integrator with input and output switching elements activated by a clock controlled time switch is used in connection with a three position room thermostat, the positions being for high and low temperatures and neutral. The input switching element has positive and negative terminals and during day operation, the time the thermostat is in its low temperature position is summed through the positive terminal. The time the thermostat is in its high temperature position is subtracted from the accumulated value of the integrator through the negative terminal.