Abstract: A monitoring system (10) for monitoring parameters of a fluid heater. The heater (30) comprises a storage vessel (32) for storing heated fluid therein. The monitoring system (10) includes a first sensor (12) and associated first electrical metering circuitry (14), a second sensor (16) and associated second electrical metering circuitry (18), and a control switch (22). The control switch (22) is operable so as to be able to adopt a first mode of operation in which the first electrical metering circuitry (14) is activated, and, a second mode of operation in which the second electrical metering circuitry is activated. The monitoring system (10) also includes a controller (24) for causing periodic operation of the control switch so that it switches between the first and second modes of operation.

Abstract: A controller for an electric booster element in a water heater is described. The electric booster element is powered from mains power and the controller comprises a control module and a capacitive module adapted to store power and supply stored power to the control module. The control module produces a control signal for controlling a relay to supply or restrict mains power supply to said booster element, said control signal depending at least in part on time of use data.

Abstract: A controller for an electric booster element in a water heater is described. The electric booster element is powered from mains power and the controller comprises a control module and a capacitive module adapted to store power and supply stored power to the control module. The control module produces a control signal for controlling a relay to supply or restrict mains power supply to said booster element, said control signal depending at least in part on time of use data.

Abstract: An electric water heater tank adapted for connection to a controller, the tank including one or more electrical heating elements temperature sensing means mounted on the exterior of the tank wall and adapted to obtain a measurement of the temperature of the water in the tank, the temperature sensing means and each heating element being connected to an externally accessible connection means. The tank can include one or more heating element control means each connected to a corresponding one of the heating elements. The element control means can be connected to the externally accessible connection means.

Abstract: A controller for an electric booster element in a water heater is described. The electric booster element is powered from mains power and the controller comprises a control module and a capacitive module adapted to store power and supply stored power to the control module. The control module produces a control signal for controlling a relay to supply or restrict mains power supply to said booster element, said control signal depending at least in part on time of use data.

Abstract: The invention provides a solar hot water heating system including one or more solar energy absorbers (102) having at least a first fluid circulation path wherein, an over temperature path (119) is provided, the over temperature path including a pressure vessel (120) which is normally closed to atmosphere, the over temperature path being connected to the first fluid circulation path (108) so that, in the event that fluid in the solar energy absorber vaporizes, the fluid is forced out of the solar energy absorber and into the pressure vessel. The present invention also provides a temperature sensitive valve leaving a flow path and a valve member operated by a thermal element having thermal expansion characteristic the valve including a support member against which the thermal element expands to force the valve element to close the flow path.

Abstract: The present invention includes a solar water heating system including: a water tank to hold water to be heated, an heat transfer fluid circuit including an heat exchanger associated with said water tank to heat water therein, a solar collection means in communication with said heat exchanger, an inlet connection to carry heat transfer fluid from said solar collection means to said heat exchanger where said water will be heated; and an outlet connection to carry heat transfer fluid from said heat exchanger to said solar collection means where said heat transfer fluid will be heated, said heat transfer fluid circuit including a reversibly evaporable heat transfer fluid which will absorb heat from said solar collection means and which will transfer said heat to said water in said water tank by means of said heat exchanger; and an diversion path being provided in said heat transfer circuit, whereby when a portion of heat transfer fluid changes to a gaseous state in said solar collection means, heat transfer fluid

Abstract: The present invention includes a solar water heating system including: a water tank to hold water to be heated, an heat transfer fluid circuit including an heat exchanger associated with said water tank to heat water therein, a solar collection means in communication with said heat exchanger, an inlet connection to carry heat transfer fluid from said solar collection means to said heat exchanger where said water will be heated; and an outlet connection to carry heat transfer fluid from said heat exchanger to said solar collection means where said heat transfer fluid will be heated, said heat transfer fluid circuit including a reversibly evaporable heat transfer fluid which will absorb heat from said solar collection means and which will transfer said heat to said water in said water tank by means of said heat exchanger; and an diversion path being provided in said heat transfer circuit, whereby when a portion of heat transfer fluid changes to a gaseous state in said solar collection means, heat transfer fluid

Abstract: A solar energy collector element having an inner tube which carries a heat exchange fluid, an outer glass tube, an evacuated space between the two tubes and a solar selective surface coating in thermal contact with the outer surface of the inner tube. A gas is admitted to the evacuated space for the purpose of degrading the vacuum and limiting the stagnation temperature of the collector element. The gas is selected to exhibit hydrophobic characteristics, to absorb onto the selective surface coating at temperatures less than a predetermined temperature to desorb into the evacuated space at temperatures greater than the predetermined temperature but not adsorb significantly onto the outer glass tube.