Heat recovery system for space heating and for potable water heating

Claim 2

A hot water heating system for both space heating and potable water heating, comprises a furnace having heat generating means therein and a flue for carrying hot, gaseous products of combustion away therefrom, a plurality of first space heating pipes connected at one of their ends in heat exchange relationship with the heat generating means in the furnace and adapted to be connected to a plurality of first space heating means to circulate hot water from the furnace to the first space heating means and back to the furnace, a storage tank for potable hot water, a cold water supply pipe connected with the potable hot water storage tank, a plurality of potable water pipes connected with the hot water tank and with the heat generating means in the furnace to heat the potable water and circulate it to a point of use, a separate heat recovery means in the flue exposed to the heat of flue gases in the flue, a plurality of heat recovery pipes connected to the potable hot water storage tank and to the heat recovery means to add heat to the water in the hot water storage tank, second space heating means separate from the first space heating means, a plurality of second space heating pipes connected to the second space heating means and to the said heat recovery means in the flue to provide hot water to the second space heating means from the heat of the flue gases, said second space heating means connected in fluid communication with the hot water storage tank, and control means operatively connected with the heat recovery pipes and with the second space heating pipes to alternately effect heat exchange between the heat recovery means and the second space heating means, and between the heat recovery means and the hot water storage tank, said control means including means to first effect supply of heat from the heat recovery means to the second space heating means in response to demand and when the demand is satisfied to effect supply of heat to the hot water storage tank, whereby the efficiency and economy of operation of the hot water heating system is greatly enhanced.

Claim 3

A hot water heating system for both space heating and potable water heating, comprises a furnace having heat generating means therein and a flue for carrying hot, gaseous products of combustion away therefrom, a plurality of first space heating pipes connected at one of their ends in heat exchange relationship with the heat generating means in the furnace and adapted to be connected to a plurality of first space heating means to circulate hot water from the furnace to the first space heating means and back to the furnace, a storage tank for potable hot water, a cold water supply pipe connected with the potable hot water storage tank, a plurality of potable water pipes connected with the hot water tank and with the heat generating means in the furnace to heat the potable water and circulate it to a point of use, a separate heat recovery means in the flue exposed to the heat of flue gases in the flue, a plurality of heat recovery pipes connected to the potable hot water storage tank and to the heat recovery means to add heat to the water in the hot water storage tank, second space heating means separate from the first space heating means, a plurality of second space heating pipes connected to the second space heating means and to the said heat recovery means in the flue to provide hot water to the second space heating means from the heat of the flue gases, said second space heating means connected in fluid communication with the hot water storage tank, and control means operatively connected with the heat recovery pipes and with the second space heating pipes to alternately effect heat exchange between the heat recovery means and the second space heating means, and between the heat recovery means and the hot water storage tank, said control means including means to first effect supply of heat from the heat recovery means to the second space heating means in response to demand and when the demand is satisfied to effect supply of heat to the hot water storage tank, whereby the efficiency and economy of operation of the hot water heating system is greatly enhanced.

Claim 4

A hot water heating system as in claim 1, wherein the space heating pipes include a return pipe connected to return water from the space heating means and a space heating supply pipe connected to supply heated water to the space heating means, said return pipe connected to one end of a space heating heat exchange means in the furnace adjacent the heat generating means, and the supply pipe connected to the other end of space heating heat exchange means, and wherein is included a potable hot water storage tank, a heat exchange coil inside said tank, said potable water pipes including a cold water supply pipe adapted to be connected to a source of potable water and connected with an inlet of the heat exchange coil in the tank, a pipe connected at one end with an outlet of the coil in the tank and connected at its other end with a potable water heat exchange means in the furnace adjacent the heat generating means, And a potable hot water discharge pipe connected at one end with the potable water heat exchange means and extending at its other end to a point of use.

Claim 5

A hot water heating system as in claim 3, wherein said separate heat recovery means comprises a heat recovery coil in said flue having an inlet end and an outlet end, said first plurality of heat recovery pipes includes a first bypass pipe connected with the return pipe and with the inlet end of the heat recovery coil and a second bypass pipe connected with the outlet end of the heat recovery coil and with the space heating supply pipe, to bypass at least a portion of the space heating water through the heat recovery coil, and said second plurality of heat recovery pipes includes a first potable water preheat pipe connected with the tank and with the inlet end of the heat recovery coil and a second potable water preheat pipe connected with the outlet end of the heat recovery coil and with the tank, to circulate water from the tank through the heat recovery coil and back to the tank to preheat potable water in the heat exchange coil in the tank.

Claim 6

A hot water heating system as in claim 4, wherein said control means includes a thermostat in a space being heated by the space heating means, and an aquastat connected in the potable hot water discharge pipe, electrical circuit means connected with the thermostat and with the aquastat, a control device connected in the circuit to receive signals from the aquastat and thermostat, a solenoid valve in each of the first bypass pipe, the second bypass pipe, the first potable water preheat pipe and the second potable water preheat pipe, said solenoid valves connected in said circuit with said control device, said solenoid valves in said first and second bypass pipes being normally open and the solenoid valves in the first and second potable water preheat pipes being normally closed, whereby water heated in said heat recovery coil is normally mixed with water in the space heating means to add heat thereto, and when a predetermined temperature is sensed by the thermostat the control device is operative to effect closing of the solenoid valves in the first and second bypass pipes and to effect opening of the solenoid valves in the first and second potable water preheat pipes to thus add heat to the potable water.

Claim 7

A hot water heating system as in claim 2, wherein the control means includes a thermostat in a space being heated by the second space heating means and an aquastat connected in operative relationship with the potable water pipes connected between the hot water tank and the heat generating means in the furnace.

Claim 8

A hot water heating system as in claim 6, wherein the separate heat recovery means includes coil means disposed in the flue and having an inlet and an outlet, said plurality of heat recovery pipes include a first pipe connected at one end thereof to the hot water storage tank near the bottom thereof and connected at the other end thereof with the inlet of the coil means, and a second pipe connected at one end thereof with the outlet of the coil means and connected at its other end with the hot water storage tank near the top thereof, and wherein said plurality of second space heating pipes includes a supply pipe connected at one end thereof with the outlet of the said coil means and connected at its other end with space heating means, and a return pipe connected at one end thereof with the space heating means and connected at its other end with the inlet of the said coil means.

Claim 9

A hot water heating system as in claim 7, wherein said control means further includes valve means in each of said first and second heat recovery pipes and in each of said supply and demand space heating pipes, valve operating control means connected with said valve means and connected with said thermostat and aquastat and responsive to conditions sensed by the thermostat and aquastat to effect opening and closing of said valve means.

Claim 10

A hot water heating system as in clAim 8, wherein said valve means are solenoid operated and said valve operating control means is operative to open the valve means in the supply and demand pipes of the space heating means when the thermostat senses a predetermined low temperature in the space being heated and to simultaneously close the valve means in the first and second pipes connected with the hot water storage tank, and said valve operating control means is operative to effect closing of said valve means in said supply and return pipes and opening of the valve means in the first and second pipes when the temperature sensed by the thermostat reaches a predetermined valve.

Claim 11

A hot water heating system as in claim 9, wherein the cold water supply pipe opens into said hot water storage tank and said first and second pipes also open into the hot water storage tank, whereby the potable water is mixed with the water for said second space heating means.

Claim 12

A hot water heating system as in claim 10, wherein a pump means is connected with said coil means to effect circulation of the water through the coil means and through the second space heating means and the hot water storage tank, and wherein said coil means comprises three coils connected in parallel.