GB2116299A

GB2116299A - A water heating system

Info

Publication number: GB2116299A
Application number: GB08202324A
Authority: GB
Inventors: John Barry Jackson
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-01-27
Filing date: 1982-01-27
Publication date: 1983-09-21

Abstract

A water heating system comprises a boiler (18) having a combustion chamber; a flue (19) extending from the combustion chamber to dispose of hot waste gases therefrom to a stack (20); a heat exchanger (22) contacted by the waste gases in the flue; a cold water storage tank (16) and a pump (25) to pass cold water from the tank through the heat exchanger and to return it, heated by the waste gases, to the tank. An air jacket (25) surrounding a flue portion (21) may be included with a fan (28) to pass air through the jacket (25) from an inlet (26) to an outlet (27) thus to recover further heat energy from the flue gases. <IMAGE>

Description

SPECIFICATION A water heating system This invention relates to a water heating system incorporating means to recover heat which in a similar conventional system is wasted to atmosphere, and is applicable particularly to central heating systems in domestic, commercial or industrial premises.

In most water heating systems the flue gases from the boiler are fed directly to a stack or balanced flue from which they pass into the atmosphere carrying with them a good deal of usable heat energy.

An object of the present invention is to provide a water heating system incorporating means to recover a substantial proportion of the heat energy from such a system.

According to the present invention there is provided a water heating system comprising a boiler having a combustion chamber, a flue extending from the boiler to dispose of hot waste gases therefrom, a heat exchange radiator contacted by the waste gases in said flue, a cold water storage tank, and a pump to pass cold water from said tank through said radiator and to return it, heated by the waste gases, to the tank.

The invention will be further apparent from a reading of the following description given by way of example only, and in which: Fig. 1 is a diagrammatic illustration of a water heating system made in accordance with the invention, and Fig. 2 is an alternative embodiment of the inventive concept.

Referring now to Fig. 1, there is illustrated in elevation a wall of a building such as a private house consisting of a ground floor area 10, an upper floor area 11 and a loft area or roof space 12. Between the ground floor area 10 and the upper floor area 11 is a floor 1 3, and a set of roof joists 1 4 mount the ceiling 1 5 of the upper floor area 11. In the loft area 12 is a cold water storage tank 16 fed in the normal way via a ball valve 17.

Situated in the ground floor area 10 is a hot water boiler 1 8 which in the conventional manner includes a combustion chamber (not shown) surrounded water jacket from which heated water is pumped to a system of radiators and a hot water storage cylinder. All of these features are of a conventional nature and form no part of the present invention. In the usual way, the pump which circulates the heated water is operably connected to a thermostatic control on the boiler such that the pump operates only when the boiler is firing as determined by the control.

Connected to the combustion chamber of the boiler 1 8 is a flue 19 which is illustrated in Fig. 1 as simple pipe. The flue 1 9 passes to stack 20 which is open at its upper end above the roof of the building. The flue 19 includes a portion 21 of greater cross-section which is some 3 metres in length and has supported internally thereof a radiator 22 of suitable shape and configuration to occupy the space within the portion 21 of the flue.

Connected to the upper end of the radiator 22 in Fig. 1 is a pipe 23 which in turn is connected to the lower region of the cold water tank 1 6. The lower end of radiator 22 is similarly connected via a pipe 24 to the upper region of the tank 1 6. In the pipe 24 there is situated a pump 25 which is operably connected to the thermostatic control of the boiler 18 such that the pump is energised simultaneously with the main system pump. In this way, cold water in the base of the tank 1 6 is circulated through radiator 22 and is heated therein by indirect contact with the hot flue gases, to be returned to the tank 1 6 thus to elevate the temperature of the water therein.

It will be appreciated that since the water in the tank 1 6 is used to feed the hot water storage cylinder heated by the boiler 18, and is pre-heated by passage through the radiator 22, at least some of the heat energy lost in the flue gases is recovered to reduce the output required of the boiler 18. In some cases, the tank 16 is employed also a header tank for the system of radiators thus again effecting a-saving in the event that the radiator system requires topping up or refilling.

Surrounding the portion 21 of the flue 19 is an air jacket 25 through which air may be circulated from an inlet pipe 26 open to the upper floor area 11, to an outlet pipe 27 open to the ground floor area 10. An electric fan 28 is positioned in the outlet pipe 27 to effect this circulation of air, and the fan is again controlled primarily from the thermostatic control on the boiler 18 and is thus operable only when the boiler is firing. In the power supply to the fan 28 there is also a further thermostatic control which senses the temperature of the water in the tank 16.This control may be pre-set at, for example, 44 degrees centigrade so that once the temperature of the water in the tank 1 6 reaches that level, and the boiler 1 8 is operative then the fan 28 is energised to draw cool air into the pipe 26 and emit heated air from the pipe 27 thus further recovering heat energy provided by the flue gases from the boiler.

Referring now to Fig. 2 in an alternative embodiment the flue pipe 19 passes upwardly through the ceiling 15 of the upper floor area 11 and is directed through a horizontal tunnel 30 which is rectangular in cross-section and its walls are formed by a plurality of radiators. At the output end of the tunnel the gas is passed to the stack 20. In this embodiment the pipes 23 and 24 are illustrated as being connected to the assembly of radiators making up the walls of the tunnel 30, and, as in Fig. 1 the pipes 23 and 24 are connected to the cold water storage tank 1 6 which is positioned elsewhere in the loft area 12.

Again, the flue gases are arranged to heat a current of air passed through an outer jacket 31 which receives cool air via an inlet pipe 26 and emits heated air via an outlet pipe 27. The system illustrated in Fig. 2 is identical in operation to the system illustrated in Fig. 1.

Although, for simplicity, the flow of water through the circuit comprising pipes 23 and 24, and radiator 22, has been shown to pass directly through the cold water storage tank 16, in an alternative arrangement pipes 23 and 24 can be joined within the tank 1 6 by means of a heating coil thus to provide an indirect heat exchanger.

Claims

1. A water heating system comprising a boiler having a combustion chamber, a flue extending from the combustion chamber to dispose of hot waste gases therefrom, a heat exchange radiator contacted by the waste gases in said flue, a cold water storage tank, and a pump to pass cdld water from said tank through said radiator and to return it, heated by the waste gases, to the tank.

2. A heating system according to Claim 1, including a hot water storage cylinder heated from said boiler and connected to said cold water storage tank for a supply of water.

3. A heating system according tq Claim 1 or Claim 2, including an air jacket surrounding at least a part of said flue thus to heat the air in said air jacket.

4. A heating system according to any preceding claim, wherein said pump is connected to actuating means associated with said boiler such that the pump and the boiler are operated simultaneously.

5. A heating system according to Claim 3, in which air is passed through said air jacket by means of a fan.

6. A heating system according to Claim 5, wherein said fan is connected to actuating means associated with said boiler and to a temperature sensing device associated with said cold water storage tank whereby said fan is actuated to pass air through said air jacket when the boiler is operating and when the temperature of the water in said cold water storage tank is at or above a pre-determined level.

7. A heating system according to any one of Claims 3, 5 and 6, wherein the direction of flow of air through said air jacket is opposite to that of the flue gases in said flue.

8. A heating system according to any preceding claim, wherein the direction of flow of water through said radiator is opposite to that of the flue gases in said flue.