Felix F Rapp

US Patent:

40601951, Nov 29, 1977

Filed:

Jul 26, 1976

Appl. No.:

5/708872

Inventors:

Felix Rapp - Marlboro MA
James M. Barron - Framingham MA

Assignee:

DIY-Sol, Inc. - Marlboro MA

International Classification:

F24J 302

US Classification:

237 1A

Abstract:

A control circuit for a solar heating system having a solar collector, a heating load and a heat transfer control unit, including a collector valve or damper for controlling the flow of heating fluid to and from the solar collector; a load valve or damper for controlling the flow of heating fluid to and from the heating load; a heating pump for moving the heating fluid; a heat exchanger; and a storage pump for circulating a storage fluid from a storage tank through the heat exchanger, the control circuit including a load sensor for sensing the temperature of the load; a collector sensor for sensing the temperature of the solar collector; a collector switching circuit responsive to an indication from the load sensor that the load temperature is below a preset level and from the collector sensor that the collector temperature is above a predetermined level, to open the dampers and activate the heating pump to move the heating fluid from the load to the collector to be heated and then returned to the load; a storage sensor for sensing the temperature of the storage fluid in the storage tank; a storage switching circuit responsive to an indication from the load sensor that the load temperature is below a preset level and from the storage sensor that the storage fluid temperature is above a predetermined level to open the load damper, close the collector damper, actuate the storage pump to move the storage fluid internally through the fluid and actuate the heating pump to move the heating fluid from the load externally through the heat exchanger to be heated and then returned to the load; and a differential switching circuit responsive to the storage sensor and the collector sensor, upon a preestablished minimum differential between the collector temperature and the storage fluid temperature, when the collector switching circuit and the storage switching circuit are inoperative in the absence of an indication from the load sensor, for actuating the storage pump to move the storage fluid internally through the heat exchanger, opening the collector damper, and closing the load damper, and actuating the heating pump for moving the heated fluid from the collector externally through the heat exchanger to increase the heat stored in the storage fluid and, when the storage switching circuit is operative, to open the collector damper and activate the storage pump to preheat the heating fluid coming from the load before it reaches the heat exchanger.