Method and control arrangement for a heating system including solar and fuel-fired heating apparatus

In a heating system for a building including fuel-fired heating apparatus having a burner means operable when energized to supply heat to a first medium, circulating means operable when energized for circulating said heated medium through areas of said building for heating said areas of the building, and thermostat means in one of said areas and operable to energize said circulator means and said burner means in response to a decrease in the temperature in said one area below a selected value, and solar heating apparatus including storage means for storing a second medium, and means for heating said second medium through solar energy, a control arrangement for enabling said first medium to be heated selectively by said burner means and said solar heating apparatus, said control arrangement comprising first sensing means operable to provide a first output indicative of the percent time for which said thermostat is operated, second sensing means for providing a second output indicative of the temperature of said second medium, switching means normally disabled to permit said burner means to be energized in response to operation of said thermostat means to supply heat to said first medium, said switching means being operable when enabled to disable said burner means and to enble said first medium to be heated by said second medium, and controller means including comparator means responsive to said first and second outputs and operable to enable said switching means whenever said second output is greater than said first output.

In a heating system for a building including at least one air conditioning unit having fuel-fired heating apparatus including a burner means for heating air supplied to a hot deck of said apparatus for circulation through a plurality of zones of the building over individual air ducts extending thereto, each of said zones have associated damper means disposed within an associated air duct and positionable by an associated damper actuator means to control the amount of heated air supplied to the zone in accordance with a control output provided to said damper actuator means by a zone thermostat located within the zone, and solar heating apparatus including solar storage means which stores a medium, and means enabling said medium to be heated by solar energy, a control arrangement for enabling air supplied to said hot deck to be heated selectively by said burner means and said solar heated medium, said control arrangement comprising monitoring means for providing a first output indicative of fuel usage by said burner means, and thus the heating demand of said system, sensing means for providing a second output indicative of the heating capability of said solar heating apparatus, and controller means responsive to said first and second outputs to interrupt a portion of an enabling circuit for said burner means and for enabling heat from said solar heated medium to heat air supplied to said hot deck whenever the heating capability of said solar heating apparatus exceeds the heating demand of the system.