Solar heat exchanger controller

Abstract

A circuit board controller enables a solar hot water system to be used in conjunction with, and assist, a conventional heating system such as a furnace. If some heat is available from solar heating, then the solar heat is used for pre-heating so the conventional heating system does not have to perform as much work. If there is enough heat available from solar heating to provide all of the heat that is needed, then operation of the conventional heating system is locked out.

1 . A solar heating arrangement for use in conjunction with a conventional heating system having a thermostat, the arrangement comprising:
 a solar heating system; and   an electronic controller electrically connected to the thermostat of the conventional heating system and to the solar heating system, the electronic controller being configured to:   lock out the conventional heating system and use heat only from the solar heating system if a liquid from the solar heating system is above a threshold temperature set by the thermostat;   supplement heat from the conventional heating system with heat from the solar heating system if the liquid from the solar heating system is below the threshold temperature set by the thermostat but is warmer than a fluid to be heated by the conventional heating system; and   lock out the solar heating system if the liquid from the solar heating system is below the threshold temperature set by the thermostat and is cooler than a fluid to be heated by the conventional heating system.   
     
     
         2 . An arrangement as in  claim 1  in which the electronic controller interconnects terminals of a thermostat with terminals of a furnace. 
     
     
         3 . An arrangement as in  claim 1  in which the electronic controller is configured to use heat from the solar heating system by turning on a circulating pump that circulates a heated fluid through coils in an air duct. 
     
     
         4 . An arrangement as in  claim 3  in which the electronic controller includes a temperature switch configured to energize a zone valve coil, the zone valve coil being configured to open and close an end switch relay, the end switch relay being configured to energize a circulator pump coil for closing a circulating pump relay for applying voltage to the circulating pump. 
     
     
         5 . An arrangement as in  claim 1  in which the electronic controller includes a temperature switch configured to energize a furnace heat pump relay coil, the furnace heat pump relay coil being configured to open and close a furnace lockout relay and/or a heat pump lockout relay for locking out the conventional heating system. 
     
     
         6 . An arrangement as in  claim 5  in which the furnace heat pump relay coil is configured to open and close a furnace lockout relay that interconnects a white terminal of a thermostat and a white terminal of a furnace. 
     
     
         7 . An arrangement as in  claim 5  in which the furnace heat pump relay coil is configured to open and close a heat pump lockout relay that interconnects a yellow terminal of a thermostat and a yellow terminal of a furnace. 
     
     
         8 . A heating arrangement comprising:
 a furnace and solar relay coil interconnecting a yellow terminal of a thermostat and a yellow terminal of a furnace, the furnace and solar relay coil being magnetically coupled to a furnace relay, a parallel combination of the furnace relay and a heat pump relay being connected in a first series combination with:
 an isolation relay; 
 a first temperature switch; and 
 a zone valve coil, 
   
       the first temperature switch being configured to sense a temperature of a liquid associated with a solar heating system, a first fixed voltage being applied across the first series combination, wherein the heat pump relay is magnetically coupled to a heat pump and solar relay coil, the heat pump and solar relay coil interconnecting the yellow terminal of the thermostat and the common terminal of the furnace, the zone valve coil is magnetically coupled to an end switch relay, the end switch relay being connected in a second series combination with a circulator pump coil, a second fixed voltage being applied across the second series combination, the circulator pump coil being magnetically coupled to a circulating pump relay, the circulating pump relay being connected in a third series combination with a circulating pump motor, a third fixed voltage being applied across the third series combination, the circulating pump motor being configured to circulate the liquid from the solar heating system, an isolation relay coil being magnetically coupled to the isolation relay, the isolation relay coil interconnecting an orange terminal of the thermostat and the common terminal of the furnace, a fourth fixed voltage being applied across a fourth series combination including a second temperature switch and a furnace heat pump relay coil, a furnace lockout relay being magnetically coupled to the furnace heat pump relay coil and interconnecting a white terminal of the thermostat and a white terminal of the furnace, and a heat pump lockout rely being magnetically coupled to the furnace heat pump relay coil and interconnecting the yellow terminal of the thermostat and the yellow terminal of the furnace. 
     
     
         9 . An arrangement as in  claim 8  in which the second temperature switch is configured to sense a temperature of the liquid from the solar heating system. 
     
     
         10 . An arrangement as in  claim 9  in which the second temperature switch is configured to open or close in response to the liquid being hot enough to perform heating. 
     
     
         11 . An arrangement as in  claim 8  in which the first, second and fourth series combinations are connected in parallel, each of the first, second and fourth voltages being a same voltage approximately between eighteen and thirty volts. 
     
     
         12 . An arrangement as in  claim 8  further comprising a cooling relay coil interconnecting the white terminal of the thermostat and the common terminal of the furnace. 
     
     
         13 . An arrangement as in  claim 8  in which a red terminal of the thermostat is directly connected to a red terminal of the furnace. 
     
     
         14 . A solar heating arrangement for use in conjunction with a conventional heating system having a thermostat, the arrangement comprising:
 a solar heating system; and   an electronic controller electrically connected to the thermostat of the conventional heating system and to the solar heating system, the electronic controller including:   means for locking out the conventional heating system and using heat only from the solar heating system if a liquid from the solar heating system is above a threshold temperature set by the thermostat;   means for supplementing heat from the conventional heating system with heat from the solar heating system if the liquid from the solar heating system is below the threshold temperature set by the thermostat but is warmer than a fluid to be heated by the conventional heating system; and   means for locking out the solar heating system if the liquid from the solar heating system is below the threshold temperature set by the thermostat and is cooler than a fluid to be heated by the conventional heating system.   
     
     
         15 . An apparatus as in  claim 14  in which the means for locking out the conventional heating system includes means for allowing the liquid from the solar heating system to circulate through a coil. 
     
     
         16 . An apparatus as in  claim 14  in which the electronic controller interconnects terminals of a thermostat with terminals of a furnace. 
     
     
         17 . An arrangement as in  claim 14  in which the electronic controller includes means for using heat from the solar heating system by turning on a circulating pump that circulates a heated fluid through coils in an air duct. 
     
     
         18 . An arrangement as in  claim 14  in which the electronic controller includes a temperature switch configured to energize a furnace heat pump relay coil, the furnace heat pump relay coil being configured to open and close a furnace lockout relay and/or a heat pump lockout relay for locking out the conventional heating system. 
     
     
         19 . An arrangement as in  claim 18  in which the furnace heat pump relay coil is configured to open and close a furnace lockout relay that interconnects a white terminal of a thermostat and a white terminal of a furnace. 
     
     
         20 . An arrangement as in  claim 18  in which the furnace heat pump relay coil is configured to open and close a heat pump lockout relay that interconnects a yellow terminal of a thermostat and a yellow terminal of a furnace.