GB1239820A - A control arrangement for a storage heater - Google Patents

Abstract

1,239,820. Control systems for thermal storoge heaters. D. R. MORRISON. 7 Nov., 1969 [7 Aug., 1968], No. 3777.5/68. Heading H2H. During the discharge period of a storage heater, charged normally during off-peak hours, the energy stored, as measured by the temperature sensed by a thermistor 1 in the core, is compared with the quantity of heat required to meet a determined thermal load during a discharge period, as determined by a synchronous timer motor-driven resistor 3. If the sensed temperature is less than the set temperature a relay 12-14 or a phase-controlled thyristor, fed through transistors 6, 11, supplies current to the heater from a normal supply. A fixed resistor 17 may extend the lower limit of temperature control. The variable resistor may be replaced by a chain of resistors connected sequentially during the discharge period. An additional temperature-sensitive resistor responsive to ambient temperature may be incorporated in the chain 1, 3, 17 which may be arranged in certain circumstances to override signals given by the other resistors. The circuit may be arranged to permit a reduction in the energy consumed during a restricted eight-hour charging period when it is estimated that the thermal load during the subsequent discharge period will be unusually low. The circuit may be applied to a space heating or hot water storage arrangement. The off-peak supply may be other than electrical.