Control system for solar heater

A solar heating system including

• solar collector means through which a heat transfer medium is circulated by pump means between the solar collector means and a reservoir,
• temperature sensing means for monitoring the temperature of the heat transfer medium and the temperature of the environment of the system which provide electronic output signals which drift representing said temperatures,
• sunlight sensing means for monitoring sunlight intensity which provide electronic output signals which drift representing said sunlight intensity,
• controller means including memory means in which is stored data representing and equilibrium curve for the collector means that enables the controller means based on the electronic output signals from the sensing means to determine if the collector means can gain or lose heat,
• said controller means operating the pump means in accordance with a predetermined program which relates the pump means operation to the ability of the collector means to either gain or lose heat as predicted by the equilibrium curve, and
• means for determining a temperature derivative for the collector means under stagnation conditions and adjusting the equilibrium curve as required by said temperature derivative determination.

A solar heating system including

• solar collector means having an inlet and an outlet,
• a reservoir having an inlet and outlet and adapted to hold a heat transfer medium, said reservoir being in communication with the solar collector means so that the heat transfer medium may be circulated between said solar collector means and the reservoir,
• pump means for circulating the heat transfer medium between the solar collector means and the reservoir, and
• monitor and control means for the system comprising
• (a) a plurality of electronic sensor means which provide an electronic output signal which drifts indicative of temperature, including
• first sensor means in the reservoir for monitoring the temperature of the medium in the reservoir,
• second sensor means at the outlet of the reservoir for monitoring the temperature of the medium as said medium exits the reservoir,
• third sensor means at the inlet of the solar collector means for monitoring temperature at the inlet to said collector means,
• fourth sensor means at the outlet of the solar collector means for monitoring the temperature at the outlet of said collector means, and
• fifth sensor means in the environment of the system for monitoring the temperature of the environment,
• (b) sunlight sensing means for measuring the intensity of the sunlight at any given point in time, said sunlight sensing means providing a signal which drifts,
• (c) means for establishing an equilibrium curve for the collector means which relates a measured sunlight intensity to a differential in temperature between a measured temperature of the heat transfer medium and a reference environmental temperature for the system, and
• (d) means for controlling the operation of the pump means in accordance with the ability of the collector means to gain or lose heat, including controller means having
• memory means in which are stored data corresponding to the equilibrium curve,
• means programmed to compare the output signals from the temperature and sunlight sensing means with said data to determine if the pump means should be turned on or off,
• means for determining a temperature derivative for the collector means under stagnation conditions and adjusting the equilibrium curve as required by said temperature derivative determination, and
• means for detecting sensor means malfunction comprising
• means for determining a temperature derivative for each of said sensor means, and, when said temperature derivative is repeatedly near zero thereby indicating sensor means malfunction, said controller means discontinuing using the output signal from said malfunctioning sensor.

A solar heating system including

• a solar collector means having an inlet and an outlet,
• a reservoir having an inlet and outlet and adapted to hold a heat transfer medium, said reservoir being in communication with the solar collector means so that the heat transfer medium may be circulated between said collector means and the reservoir,
• pump means for circulating the heat transfer medium between the solar collector means and the reservoir, and
• monitor and control means for the system comprising
• (a) a plurality of electronic sensor means which provide an electronic output signal indicative of temperature, said output signal drifting, including
• first sensor means in the reservoir for monitoring the temperature of the medium in the reservoir,
• second sensor means for monitoring the temperature of said collector means,
• (b) sunlight sensor means for measuring sunlight intensity at any given point in time, said sunlight sensing means providing a signal which drifts,
• (c) means for establishing an equilibrium curve for the collector means which relates the sunlight intensity to a differential in temperature between the temperature of the heat transfer medium in the reservoir and a reference environmental temperature for the system, and
• (d) means for controlling the operation of the pump means in accordance with the ability of the collector means to gain or lose heat, including controller means having
• memory means in which are stored data corresponding to the equilibrium curve,
• means programmed to compare the output signals from the temperature and sunlight sensor means to determine if the pump should be turned on or off, and
• means for periodically determining a temperature derivative for the collector means under stagnation conditions and adjusting the equilibrium curve as required by said temperature derivative determination.

A monitor and controller for a solar heating system having solar collector means in communication with a reservoir holding a heat transfer medium, and pump means for circulating the heat transfer medium between the solar collector means and the reservoir, said monitor and controller including

• (a) a plurality of electronic sensor means which provide an electronic output signal indicative of temperature, said signal from said sensor means drifting, including
• first sensor means in the reservoir for monitoring the temperature of the medium in the reservoir,
• second sensor means for monitoring the temperature of said solar collector means,
• (b) means for measuring sunlight intensity at any given point in time, said intensity measuring means providing a signal which drifts,
• (c) means for establishing an equilibrium curve for the system which relates a measured sunlight intensity to a differential in temperature between a measured temperature of the heat transfer medium and a reference environmental temperature for the system, and
• (d) means for controlling the operation of the pump means in accordance with the ability of the solar collector means to gain or lose heat, including
• memory means in which are stored data corresponding to the equilibrium curve,
• means programmed to compare the output signals from the temperature sensors and the means for measuring the intensity of the sunlight with said data to determine if the pump means should be turned on or off, and
• means for determining a temperature derivative for the system under stagnation conditions and readjusting the equilibrium curve as required by said temperature derivative determination.