Interface circuit for adding solar heat to a building heating and cooling system
AssigneeSolar Unlimited, Inc.
InventorsDonald R. Bowden, Robert O. Sparks
Life of this patent
Estimating the term…
Abstract
An interface circuit for adding a solar heat system to a building having a building heating and cooling system and having a building thermostat system, the interface circuit being especially wired to be compatibly interposed between the building thermostat system and the building heating and cooling system without rewiring the latter and being also connected to the solar heat system, the interface circuit thereby adding the solar system as a heat source, and the interface circuit automatically substituting the solar source for the building heating system when heat is called for at a level within the capability of the solar system to supply.
Claims3
In building heating and cooling apparatus including building heating and cooling thermostats connected through terminals to relays controlling a building fuel-consuming heating and cooling system and controlling a building duct air circulating fan wherein said relays are energized by power from a building control voltage transformer, an interface control to be interposed at said terminals between the building thermostats and the building heating and cooling system relays for introducing and controlling an auxiliary solar heat system having a thermal storage medium circulated by a pump into heat exchange relationship with said duct, the temperature of the medium being measured by an aquastat including a heat-responsive switch, said interface comprising:
- an electrical circuit having thermostat and heating and cooling and fan terminals corresponding with and interposed between the terminals of the building thermostats and of the building heating and cooling and fan system, and the circuit additionally having solar system aquastat and pump terminals;
- first relay means in the electrical circuit having contacts operative upon closing of a building heating thermostat to deliver power to the building heating system and to the aquastat switch;
- solar system relay means responsive to power delivered to the aquastat switch when closed and having contacts operative to interrupt power through the first relay contacts to the building heating system and operative to deliver power to the solar system circulation pump;
- means to energize the air circulation fan of the building when a thermostat is closed;
- and
- third relay means operative when a building cooling system thermostat is closed and having contacts connected to interrupt the solar system relay means and prevent it from energizing the solar system circulation pump.
Dependencies are inferred from the claim text.