Heating System Including A Refrigerant Boiler

Abstract

A heating system includes a refrigerant boiler including a heat source for heating a refrigerant from a liquid state to a vapor state, a boiler outlet and a boiler inlet; a heat exchanger in fluid communication with the refrigerant boiler, the heat exchanger including a upper manifold having a heat exchanger inlet coupled to the boiler outlet, a lower manifold having a heat exchanger outlet coupled to the boiler inlet and a plurality of tubes connecting the upper manifold and the lower manifold, wherein refrigerant passes from the upper manifold to the lower manifold via gravity; and a fan moving air over the heat exchanger to define supply air for a space to be heated.

1 . A heating system comprising:
 a refrigerant boiler including a heat source for heating a refrigerant from a liquid state to a vapor state, a boiler outlet and a boiler inlet;   a heat exchanger in fluid communication with the refrigerant boiler, the heat exchanger including a upper manifold having a heat exchanger inlet coupled to the boiler outlet, a lower manifold having a heat exchanger outlet coupled to the boiler inlet and a plurality of tubes connecting the upper manifold and the lower manifold, wherein refrigerant passes from the upper manifold to the lower manifold via gravity; and   a fan moving air over the heat exchanger to define supply air for a space to be heated.   
     
     
         2 . The heating system of  claim 1  further comprising:
 a first valve downstream of the boiler controlling flow of vapor refrigerant to the heat exchanger inlet; 
 a second valve upstream of the boiler controlling flow of liquid refrigerant to the boiler inlet; 
 and a controller for selectively opening and closing the first valve and second valve to control flow of refrigerant between the boiler and heat exchanger. 
 
     
     
         3 . The heating system of  claim 2  wherein:
 in a first state the first valve and second valve are closed, the controller opening the first valve in response to at least one of temperature and pressure in the boiler. 
 
     
     
         4 . The heating system of  claim 3  wherein:
 the controller opens the second valve after the first valve is opened. 
 
     
     
         5 . The heating system of  claim 4  wherein:
 the controller closes the first valve and closes the second valve after a predetermined period of time. 
 
     
     
         6 . The heating system of  claim 1  further comprising:
 an accumulator positioned between the outlet of the heat exchanger and the inlet of the boiler. 
 
     
     
         7 . The heating system of  claim 6  further comprising:
 a check valve is positioned upstream of the accumulator. 
 
     
     
         8 . The heating system of  claim 1  further comprising:
 a receiver positioned between the outlet of the heat exchanger and the inlet of the boiler. 
 
     
     
         9 . The heating system of  claim 8  further comprising:
 a check valve is positioned downstream of the receiver. 
 
     
     
         10 . The heating system of  claim 1  wherein:
 the boiler includes a first heat exchanger section and a second heat exchanger section arranged in a counterflow manner with respect to flue gas flow from the boiler, the second heat exchanger section including a tray for collecting flue gas condensate and a condensate drain coupled to the tray. 
 
     
     
         11 . The heating system of  claim 10  further comprising:
 a liquid-vapor separator positioned between the first heat exchanger section and the second heat exchanger section, a vapor portion of the liquid-vapor separator being coupled to an inlet of the heat exchanger, a liquid portion of the liquid-vapor separator being coupled to an inlet of the first heat exchanger section. 
 
     
     
         12 . The heating system of  claim 1  further comprising:
 a temperature sensor positioned to monitor temperature of the supply air; and 
 a controller receiving a temperature signal from the temperature sensor and controlling a speed of the fan in response to the temperature signal. 
 
     
     
         13 . The heating system of  claim 1  further comprising:
 a sensor detecting an operational parameter of the refrigerant boiler; 
 a flue gas fan directing flue gas over a boiler heat exchanger of the refrigerant boiler; and 
 a controller for controlling at least one of the heat source of the refrigerant boiler and the flue gas fan in response to the sensor. 
 
     
     
         14 . The heating system of  claim 13  wherein:
 the heat source is a staged burner having a burner stage valve to control fuel flow to an additional burner stage; 
 the controller controls the burner stage valve in response to the sensor. 
 
     
     
         15 . The heating system of  claim 13  further comprising:
 a fuel flow control device to control fuel flow to the heat source; 
 the controller controlling the fuel flow control device in response to the sensor. 
 
     
     
         16 . The heating system of  claim 15  wherein:
 the controller controls the fuel flow control device to one of modulate or pulsate fuel to the heat source. 
 
     
     
         17 . The heating system of  claim 13  wherein:
 the flue gas fan is one of a two speed fan, a variable speed fan, and multiple fans, controlled by the controller in response to the sensor. 
 
     
     
         18 . The heating system of  claim 1  further comprising:
 a trap positioned between the lower manifold and the heat exchanger outlet, the trap holding liquid refrigerant. 
 
     
     
         19 . The heating system of  claim 1  wherein:
 the heat exchanger inlet and the heat exchanger outlet are coupled to a single pipe carrying both vapor refrigerant and liquid refrigerant. 
 
     
     
         20 . The heating system of  claim 14  further comprising:
 a tube coupled to the heat exchanger outlet, the tube positioned inside a portion of the pipe.