GB2218498A - Improvements in or relating to a heating and hot water supply arrangement - Google Patents
Improvements in or relating to a heating and hot water supply arrangement Download PDFInfo
- Publication number
- GB2218498A GB2218498A GB8811182A GB8811182A GB2218498A GB 2218498 A GB2218498 A GB 2218498A GB 8811182 A GB8811182 A GB 8811182A GB 8811182 A GB8811182 A GB 8811182A GB 2218498 A GB2218498 A GB 2218498A
- Authority
- GB
- United Kingdom
- Prior art keywords
- water
- heating circuit
- tank
- heat exchanger
- boiler
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
- F24D3/00—Hot-water central heating systems
- F24D3/08—Hot-water central heating systems in combination with systems for domestic hot-water supply
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- Engineering & Computer Science (AREA)
- Water Supply & Treatment (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Steam Or Hot-Water Central Heating Systems (AREA)
Abstract
In a heating and hot water supply arrangement utilising a combination boiler 1, water from a cold water supply 4 fed to the heat exchanger 2 within the boiler 1 before being discharged through the hot water outlet 5 is pre-heated in a heat exchanger 9 which receives heat from water present in the heating circuit 7, 8 which has been previously heated by the heat exchanger 3 within the boiler 1. Thus, since the water supplied to the boiler is pre-heated, the output temperature and/or flow of the hot water discharged through the outlet 5 is increased. <IMAGE>
Description
Description of the Invention "Improvements in or relating to a heating and hot water supply arrangement"
THE PRESENT INVENTION relates to a heating and hot water supply arrangement and more particularly to a heating and hot water supply arrangement that utilises a so-called "combination" boiler.
In recent years there has been an increasing use of gas-fired combination boilers. Such a boiler serves the dual purpose of acting as the heat source for a central heating system, and also provides hot water.
However, the hot water is heated, by the boiler, "instantaneously" as the water is used. It is therefore not necessary to have a hot water tank. The boiler may be fed directly from the main water supply, and thus it may also be possible to avoid utilising a cold water tank.
Figure 1 of the accompanying drawings illustrates a conventional heating and hot water supply arrangement which utilises a combination boiler.
Referring to Figure 1 a combination boiler 1 contains within it two heat exchangers 2,3, adapted to heat water flowing through the boiler. The two heat exchangers may be in a single heat exchange unit or block which defines two flow paths for water to be heated.
The heat exchanger 2 is fed directly from a cold water supply 4 and is connected to a hot water out let 5. The heat exchanger 3 is associated with a pump 6 contained within the boiler, which is adapted to pump water returning from radiators in the heating circuit, through a return line 7, through the heat exchanger 3 and then to the radiators through a supply line 8. The pump 6 is adapted to be switched off whenever there is a flow through the heat exchanger 2. Thus only one of the two heat exchangers 2,3 is operationl at any instant.
The heating circuit is usually pressurised, and has a pressure of up to 3 bars. An expansion vessel is provided in the boiler to allow for the expansion of water in the heating circuit as it warms up.
A typical combination boiler, as described, has relatively low capacity heat exchangers 2,3. The heat exchangers may be quite adequate to provide hot water for a central heating system incorporating radiators, but the boiler may have some shortcomings when supplying hot water. Since the capacity of the heat exchanger 2 is restricted, it is only possible to provide a relatively low flow of water through the hot water outlet 5. Thus, if it is desired to fill a bath, for example, it may take. fifteen or twenty minutes for sufficient water to be heated by the boiler for this purpose. A further problem is that if the water is supplied directly to a kitchen sink at an adequate flow rate, the temperature of the water may not be high enough to enable the water to be readily used for washing-up.This problem may be particularly experienced if the temperature of cold water coming in through the cold water feed 4 is very low.
The present invention seeks to provide a heating and hot water supply arrangement in which these problems are obviated or reduced.
According to this invention there is provided a combined heating and hot water supply arrangement comprising a boiler having heat exchanger means to heat a flow of water in a heating circuit and having means to heat a flow of water from a cold water supply to be discharged as hot water, the cold water supply passing through heat exchanging means connected to the heating circuit, so that, in use, cold water supplied to the boiler is pre-heated with heat from water in the heating circuit.
Preferably the heat exchanging means in the heating circuit comprise a tank through which water in the heating circuit flows, the tank containing a heat exchanging coil through which water from the cold supply flows before entering the boiler.
Conveniently the tank is thermally insulated.
Advantageously the tank is adapted to contain between 22 and 67 litres of water within the heating circuit.
Preferably the tank is adapted to contain approximately 36 litres of water in the heating circuit.
Advantageously the surface area of the heat exchanging coil within the tank between 2,000 and 7,000 sq. cms. and preferably is approximately 5,500 sq. cms.
Alternatively pump means are provided to pump water round the heating circuit but not through the heat exchanger means in the boiler when cold water is being supplied through the heat exchanger to the boiler for discharge as hot water. In this case the heat exchanger may be relatively small, having a volume between 0.5 and 5 litres.
Conveniently said pump means is connected between a radiator supply line and a radiator return line, and is additional to a pump provided in the boiler which normally pumps water in the heating circuit.
In an alternative arrangement said pump is a pump provided in the boiler, a bypass which bypasses the heat exchanger in the boiler being opened when said cold water is being supplied to the boiler.
Preferably said pump means are provided with a one-way valve.
Conveniently the pump means are adapted to pump water within the heating circuit in the reverse direction as compared with the normal flow of water within the heating circuit.
This invention also relates to a heat exchanger for use in an arrangement as described above, said heat exchanger comprising a vessel adapted to be connected in a heating circuit, the vessel having a maximum height of 60 centimetres, and a maximum diameter of 35 centimetres, the tank being thermally insulated, and being adapted to contain between 22 and 67 litres of water in the heating circuit, the tank containing a heat exchanging coil.
Preferably the heat exchanging coil has an exposed surface on the interior of the tank of between 2,000 and 7,000 sq. cms., most preferably approximately 5,500 sq. cms.
Conveniently the tank is thermally insulated with an outer layer of at least 2.5 centimetres of foamed material.
In order that the invention may be more readily understood and so that further features thereof may be appreciated, the invention will now be described by way of example with reference to the accompanying drawings in which,
FIGURE 2 is a view, corresponding to Figure 1, showing an arrangement in accordance with the invention, and
FIGURE 3 is a further view, corresponding to
Figure 1, showing a further arrangement in accordance with the invention.
The parts of Figure 2 that are the same as the arrangement shown in Figure 1 carry the same reference numerals and will not be re-described.
In the embodiment of the invention illustrated in Figure 2 water from the cold water supply 4 passes through a heat exchanger coil 9 which is located within a small tank 10 which is connected in the supply line 8 extending to the radiators in the central heating system.
It will therefore be understood that, in operation of the arrangement, the tank 10 will be filled with water which is to flow round the heating circuit.
This water, when the heating system is in use, will be heated to a high temperature by the heat exchanger 3.
The heat exchanger 3 has a sufficient capacity that it can maintain a series of radiators at a high temperature, and thus the heat exchanger 3 will also be able to maintain the water within the tank 10 at a high temperature. The heated water from the heat exchanger 3 entering the tank 10 will pass through the tank and will leave that tank through the line 8.
The tank 10 is designed to be able to withstand a pressure of three bars or more, since conventionally the heating circuit of a combination boiler operates at such a pressure. The tank is thermally insulated, preferably with applied insulating foam having a thickness of at least 2.5 centimetres. The tank may be up to 60 centimetres high and may be square or circular in plan having a diameter of up to 35 centimetres or having sides of a length of up to 35 centimetres. The tank may thus be accommodated within a conventional sized kitchen unit. Preferably the extent of the heat exchanger coil 9 within the tank is significant, with a large surface area between the heat exchanger coil 9 and the interior of the tank 10. This surface area may be in the range of 2,000 to 7,000 sq. cms., a preferred value being 5,500 sq. cms.Preferably the tank is dimensioned to contain between 22 dm3 and 67 dm3 of water passing from the heat exchanger 3 through the radiator supply line 8. Most preferably the tank 10 is dimensioned to accommodate approximately 36 dm3 of such water. In use, the tank 10 acts as a reservoir or store of heat which can be used when there is a demand for hot water.
In operation of the described arrangement, when the boiler is in the ordinary operating state, the pump 6 will pump heating circuit water through the heat exchanger 3, where the water is heated, and thence through the tank 10 to the radiator supply line 8. In this mode the tank 10 does not perform any real function. However, since the tank 10 is well thermally insulated there is no heat loss from the tank 10. When there is a demand for hot water, in other words when a hot water tap is turned on, a flow sensor within the boiler turns off the pump 6, thus terminating the flow of water in the heating circuit. As water from the cold water supply 4 flows through the heat exchanger 2, of the boiler that water is heated. However, the water from the cold water supply 4 passes through the heat exchanger coil 9 within the tank 10 before entering the boiler.As the water passes through this heat exchanger coil 9 its temperature is raised, heat being extracted from the hot heating circuit water remaining in the tank 10. As the thus warmed water passes through the heat exchanger 2 in the boiler, the temperature is raised even more. Thus, after a very short initial flow of cool water, water having a very high temperature passes through the hot water outlet 5. This water may have a significant flow rate. Such water may be ideal for use in washing-up. This flow of water at a high temperature continues until all the heat present in the water stored in the tank 10 has been transferred, by means of the heat exchanger 9, to cold water passing into the boiler from the cold water supply 4. The boiler will then produce hot water at the same temperature that it would ordinarily have produced when in the configuration shown in Figure 1.Thus, if the hot water is used for a bath, by adding some cold water to the initial high temperature flow it is possible to fill a bath to a predetermined depth and a predetermined temperature more quickly than with the arrangement of Figure 1.
It will therefore be appreciated that a heating and hot water supply arrangement in accordance with the invention as illustrated in Figure 2 is provided with heat exchanging means which pre-heat cold water entering the boiler from a cold water supply with heat that is already present in the heating circuit. This is heat which would otherwise be used usefully by the heating circuit. It is to be realised, of course, that when there is a demand for hot water the heating circuit ceases to operate, and also heat is extracted from the heating circuit. Thus it may take some period of time for the heating circuit to recover. However, in a cen trally heated house, it is possible to dis-able the heating system for quite a lengthy period of time before the temperature drops noticably.
The arrangement illustrated in Figure 2 may be modified by providing an optional controllable bypass connection between the radiator supply line 8 and the radiator return feed 7, as illustrated by the dotted connection 11. This bypass connection may be opened during the summer months, when the radiators are not in use. Thus, even during the summer months the tank 10 will be maintained full of hot water, to enable the system to provide an output flow of hot water through the hot water outlet 5 in the manner described above.
Figure 3 illustrates a modified embodiment of the invention. In this embodiment of the invention the cold water supply 4 passes through a heat exchanging coil 12 in a heat exchanger 13 of small capacity which is present in the radiator supply line 8 of the heating circuit. The heat exchanger 13 may be a conventional heat exchanger which contains between 0.5 and 5 litres of water in the heating circuit. However, adjacent the boiler 1 there is provided a pump 13, which is additional to the pump 6, and an associated non-return valve 14, connected between the radiator supply line 8 and the radiator return line 7.
The illustrated arrangement is arranged to operate so that, in the ordinary state, the pump 13 is not operational. The pump 6 will then pump water through the heat exchanger 3, through the heat exchanger 13 and thus to the radiator supply line 8.
However, when there is a demand for hot water, and water starts to flow through the heat exchanger 2, the pump 6 ceases to operate, and the pump 13 commences operation. The pump 13 may serve to pump water around the heating circuit in the same direction as the pump 6 or may preferably pump water around the heating circuit in the opposite direction. In any event, water from the heating circuit is pumped through the heat exchanger 13 at the same time as water from the cold supply line 4 passes through the heat exchanger 12. The water passing through the heat exchanger 12 thus has its temperature raised with heat from the water in the heating circuit and the thus warmed water enters the heat exchanger 2 to have its temperature raised still further, as in the embodiment described above.
In this arrangement, if the pump 13 pumps the water in the heating circuit in the reverse sense, initially the hottest water in the heating circuit will pass through the heat exchanger 13, thus ensuring that during the initial period of the supply of hot water through the hot water outlet 5, water at the highest practicable temperature is supplied. Of course, water passing through the heat exchanger 13 will be pre-heated so long as there is any useful heat contained within the water circulating in the heating circuit under the influence of the pump 13. Thus this system again utilises heat present in the heating circuit to pre-heat water that is to pass through the heat exchanger 2 and which is to be discharged as hot water.
The system illustrated in Figure 3 may be modified so that only one pump, for example the pump 6 present in the boiler, is provided. The arrangement will be such that ordinarily the pump 6 will pump the water of the heating circuit through the heat exchanger 3 and then around the heating circuit. However, when there is a demand for hot water appropriate valves will open and close, so that the heat exchanger 3 is bypassed and the pump 6 just pumps water around the heating circuit.
Whilst the invention has been described by way of example it is to be appreciated that many modifications may be effected without departing from the scope of the invention as defined by the following Claims.
Claims (20)
1. A combined heating and hot water supply arrangement comprising a boiler having heat exchanger means to heat a flow of water in a heating circuit and having means to heat a flow of water from a cold water supply to be discharged as hot water, the cold water supply passing through heat exchanging means connected to the heating circuit, so that, in use, cold water supplied to the boiler is pre-heated with heat from water in the heating circuit.
2. An arrangement according to Claim 1 wherein the heat exchanging means in the heating circuit comprise a tank through which water in the heating circuit flows, the tank containing a heat exchanging coil through which water from the cold supply flows before entering the boiler.
3. An arrangement according to Claim 2 wherein the tank is thermally insulated.
4. An arrangement according to Claim 2 or 3 wherein the tank is adapted to contain between 22 and 67 litres of water within the heating circuit.
5. An arrangement according to Claim Ii wherein the tank is adapted to contain approximately 36- litres of water in the heating circuit.
6. An arrangement according to Claim 2, 3 or 4 wherein the surface area of the heat exchanging coil within the tank is between 2,000 and 7,000 sq. cms.
7. An arrangement according to Claim 6 wherein the surface area of the heat exchanging coil within the tank is approximately 5,500 sq. cms.
8. An arrangement according to Claim 1 wherein pump means are provided to pump water round the heating circuit but not through the heat exchanger means in the boiler when cold water is being supplied through the heat exchanger to the boiler for discharge as hot water.
9. An arrangement according to Claim 8 wherein said pump means is connected between a radiator supply line and a radiator return line, and is additional to a pump provided in the boiler which normally pumps water in the heating circuit.
10. An arrangement according to Claim 8 wherein said pump is a pump provided in the boiler, a bypass which bypasses the heat exchanger in the boiler being opened when said cold water is being supplied to the boiler.
11. An arrangement according to Claim.9 wherein said pump means are provided with a one-way valve.
12. An arrangement according to any one of Claims 8 to 11 wherein the pump means are adapted to pump water within the heating circuit in the reverse direction as compared with the normal flow of water within the heating circuit.
13. A heat exchanger for use in an arrangement according to any one of Claims 1 to 6, said heat exchanger comprising a vessel adapted to be connected in a heating circuit, the vessel having a maximum height of 60 centimetres, and a maximum diameter of 35 centimetres, the tank being thermally insulated, and being adapted to contain between 22 and 67 litres of water in the heating circuit, the tank containing a heat exchanging coil.
14. A heat exchanger according to Claim 13 wherein the heat exchanging coil has an exposed surface on the interior of the tank of between 2,000 and 7,000 sq. cms.
15. A heat exchanger according to Claim 14 wherein the heat exchanging coil has an exposed surface on the interior of the tank of approximately 5,500 sq. cms.
16. A heat exchanger according to Claim 13, 14 or 15 wherein the tank is thermally insulated with an outer layer of at least 2.5 centimetres of foamed material.
17. A heating and hot water supply arrangement substantially as herein described with reference to and as illustrated in Figure 2 of the accompanying drawings.
18. A heating and hot water supply arrangement substantially as herein described with reference to and as shown in Figure 3 of the accompanying drawings.
19. A heat exchanger according to Claim 13 and substantially as herein described.
20. Any novel feature or combination of features disclosed herein.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8811182A GB2218498B (en) | 1988-05-11 | 1988-05-11 | Improvements in or relating to a heating and hot water supply arrangement |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8811182A GB2218498B (en) | 1988-05-11 | 1988-05-11 | Improvements in or relating to a heating and hot water supply arrangement |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8811182D0 GB8811182D0 (en) | 1988-06-15 |
| GB2218498A true GB2218498A (en) | 1989-11-15 |
| GB2218498B GB2218498B (en) | 1992-09-02 |
Family
ID=10636742
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8811182A Expired - Fee Related GB2218498B (en) | 1988-05-11 | 1988-05-11 | Improvements in or relating to a heating and hot water supply arrangement |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2218498B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2722560A1 (en) * | 1994-07-18 | 1996-01-19 | Famchon Michel | Domestic gas boiler for central heating and water heating |
| NL1000210C2 (en) * | 1995-04-24 | 1996-10-25 | Apparatenfabriek Warmtebouw B | Combi boiler with improved performance. |
| AT402663B (en) * | 1995-04-26 | 1997-07-25 | Vaillant Gmbh | HOT WATER HEATER HOT WATER HEATER |
| GB2365953A (en) * | 2000-07-07 | 2002-02-27 | George Curtis | Supplementary heat exchanger arrangement for providing domestic hot water |
| GB2382124A (en) * | 2001-11-14 | 2003-05-21 | Henrik Moore | Heat exchange system with pre-heater |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB897424A (en) * | 1957-03-05 | 1962-05-30 | Gossalter Rene | Improvements in or relating to central heating and hot water supply systems |
| GB1113284A (en) * | 1964-09-19 | 1968-05-08 | Vaillant Joh Kg | Gas heated continuous-flow heater for central heating water and domestic water |
-
1988
- 1988-05-11 GB GB8811182A patent/GB2218498B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB897424A (en) * | 1957-03-05 | 1962-05-30 | Gossalter Rene | Improvements in or relating to central heating and hot water supply systems |
| GB1113284A (en) * | 1964-09-19 | 1968-05-08 | Vaillant Joh Kg | Gas heated continuous-flow heater for central heating water and domestic water |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2722560A1 (en) * | 1994-07-18 | 1996-01-19 | Famchon Michel | Domestic gas boiler for central heating and water heating |
| NL1000210C2 (en) * | 1995-04-24 | 1996-10-25 | Apparatenfabriek Warmtebouw B | Combi boiler with improved performance. |
| EP0740113A1 (en) * | 1995-04-24 | 1996-10-30 | Apparatenfabriek Warmtebouw B.V. | Combined heating boiler with improved performance |
| AT402663B (en) * | 1995-04-26 | 1997-07-25 | Vaillant Gmbh | HOT WATER HEATER HOT WATER HEATER |
| GB2365953A (en) * | 2000-07-07 | 2002-02-27 | George Curtis | Supplementary heat exchanger arrangement for providing domestic hot water |
| GB2365953B (en) * | 2000-07-07 | 2004-08-25 | George Curtis | Heating systems |
| GB2382124A (en) * | 2001-11-14 | 2003-05-21 | Henrik Moore | Heat exchange system with pre-heater |
| GB2382124B (en) * | 2001-11-14 | 2005-03-30 | Henrik Moore | Heat exchange system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2218498B (en) | 1992-09-02 |
| GB8811182D0 (en) | 1988-06-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19950511 |