초록 ▼

A heating system for a building comprises a boiler and radiators to which hot water is supplied from the boiler, in which at least some of the return water flow from the radiators, typically at 6째 C. , circulates through a first heat exchanger to cool the exhausting products of combustion, means is

A heating system for a building comprises a boiler and radiators to which hot water is supplied from the boiler, in which at least some of the return water flow from the radiators, typically at 6째 C. , circulates through a first heat exchanger to cool the exhausting products of combustion, means is provided to direct a small part of the return water flow through at least one heat exchanger which gives up heat to the building and/or to the boiler heating the water for heating he building, to cool the diverted water to well below the dew point, and means is provided to supply the cooled water to a second heat exchanger through which the already cooled exhaust products of combustion have to pass after leaving the first heat exchanger, to achieve full condensation of the water vapour content of the products of combustion form the boiler.

대표청구항 ▼

What is claimed is: 1. A heating system for a building comprising a boiler and radiators for heating different regions of the building which are supplied with hot water from the boiler and in which the boiler and radiators are all in the building, wherein the boiler includes a burner for burning a

What is claimed is: 1. A heating system for a building comprising a boiler and radiators for heating different regions of the building which are supplied with hot water from the boiler and in which the boiler and radiators are all in the building, wherein the boiler includes a burner for burning a hydrocarbon fuel such as gas or oil in a combustion chamber, and a heat recovery system is provided by which heat which would normally be lost in the hot exhaust gases leaving the combustion chamber is recovered therefrom, wherein the heat recovery system comprises heat exchange means through which water returning from the radiators is caused to flow, and through which water at a temperature below the dew point of the water vapour in the flue gases is also caused to flow to cool the hot gases to recover the latent heat of vaporisation from the water vapour therein, and wherein the heat exchange means includes primary and secondary water circuits, water in the secondary circuit being in direct contact with the hot flue gases so that the condensed water and any water soluble products of combustion can mix with the cooling water and will leave the heat exchange means with the cooling water, characterised by means for diverting a proportion of the water returning to the boiler from the radiators from an exit in the return path to a further heat exchange means located within a region of the building which is maintained at a lower temperature than other regions of the building thereby to cool the diverted water to a temperature below the dew point, means for conveying the cooled diverted water via the primary water circuit in the heat exchange means to re-enter the return water path to the boiler, downstream of the exit point from which it was diverted, to return to the boiler for reheating, and a pump is provided for pumping water in the secondary water circuit from a region in which it is cooled by the cooled diverted water flowing through the primary circuit to an upper region to form a cascade in which the hot gases are mixed therewith. 2. A heating system as claimed in claim 1 wherein the further heat exchange means includes a radiator in the lower temperature region of the building. 3. A heating system as claimed in claim 1 wherein the further heat exchange means includes a water to water heat exchanger in a reservoir of cold water provided for supplying cold water to the building. 4. A heating system as claimed in claim 3 which includes a thermostatically controlled valve adapted to restrict the flow of water to the said water to water heat exchanger if the temperature of the water in the storage reservoir exceeds a preset temperature. 5. A heating system as claimed in claim 1 wherein the heat exchange means includes an air to water heat exchanger located in an air intake to the burner of the boiler through which air to support combustion passes on route to the combustion chamber. 6. A heating system as claimed in claim 1 wherein the heat recovery system heat exchange means comprises first and second heat exchange means through one of which water returning from the radiators is caused to flow, and through the other of which water at a temperature below the dew point of the water vapour in the flue gases is caused to flow. 7. A system as claimed in claim 1 wherein the volume of diverted water is in the range of 0.5-1.0 liters/minute. 8. A method of cooling the products of combustion (flue gases) of a fossil (i.e. hydrocarbon based) fuel burning water heating apparatus (a boiler) which in use heats water for circulation by a pump around a closed circuit containing radiators and a main heat exchanger by which it is heated by the burning of the fossil fuel in air in a burner in the boiler, and wherein the flue gases pass through secondary heat exchange means by which they are cooled below the dew point temperature of water vapour in the flue gases so that the water condenses and is thereby separated from the flue gases, and wherein a portion of the circulating water is diverted from the main flow at a point just prior to its return to the main heat exchanger, and the diverted flow is cooled by further heat exchange means to a temperature substantially below the dew point temperature, and wherein the cooled water is employed in the condensing heat exchange step in the secondary heat exchange means to cool the gases below the said dew point and is thereafter returned to the main return water flow to the main heat exchanger downstream of the point at which the portion of the circulating water was diverted. 9. A method as claimed in claim 8 wherein the said condensing cooling step involves a mixing of the flue gases and the cooled circulating water, and the condensing of the water vapour by the said further cooling step increases the volume of water circulating around the generally closed circuit and an overflow or syphon is provided to maintain the volume of circulating water substantially constant, the water and flue gases are separated using gravity before the flue gases exit to atmosphere, and the recovered water drains into a low level reservoir forming part of the said generally closed circuit and a coiled pipe in the reservoir provides a path for the low temperature water by which the heat is exchanged between the water in the reservoir and the low temperature water, to cool the water in the reservoir to below the dew point. 10. A method as claimed in claim 8 wherein the flue gases are progressively cooled in the secondary heat exchange means by a said first cooling step to a temperature above the dew point, and thereafter by the condensing cooling step in which they are cooled to below the dew point by low temperature water which is circulated around a generally closed circuit and which is cooled to substantially below the dew point temperature. 11. A method as claimed in claim 10 wherein the said condensing cooling step involves a mixing of the flue gases and the cooled circulating water, and the condensing of the water vapour by the said further cooling step increases the volume of water circulating around the generally closed circuit and an overflow or syphon is provided to maintain the volume of circulating water substantially constant, the water and flue gases are separated using gravity before the flue gases exit to atmosphere, and the recovered water drains into a low level reservoir forming part of the said generally closed circuit and a coiled pipe in the reservoir provides a path for the low temperature water by which the heat is exchanged between the water in the reservoir and the low temperature water, to cool the water in the reservoir to below the dew point.