GB2181526A

GB2181526A - Domestic hot water systems

Info

Publication number: GB2181526A
Application number: GB08624482A
Authority: GB
Inventors: George Hanson-Graville
Original assignee: HYDRO SPARTAN Ltd
Current assignee: HYDRO SPARTAN Ltd
Priority date: 1985-10-14
Filing date: 1986-10-13
Publication date: 1987-04-23
Also published as: GB8624482D0; GB2181526B

Abstract

A domestic hot water system comprises a satellite cylinder 4 for water to be heated rapidly. The main cylinder 1 is heated indirectly by a coil having an inlet 2 and an outlet 3 which communicates with the return feed D to the boiler or other heating source. A hot water draw-off outlet A from the cylinder 1 is connected to the satellite cylinder 4 and this includes an outlet B which then serves as the water supply draw-off. Within the satellite tank 4 is located a finned heat exchange unit with an inlet C for connection with the hot water supply of the boiler and an outlet which connects with the input side of a changeover valve E. The valve E may be set by means of a control 5 to direct the heating water supply output from the satellite tank 4 either through pipe F to the inlet 2 of the coil in the cylinder or through pipe 6 to directly communicate with the outlet D thereby by-passing the coil to heat water in tank 4 rapidly. The heat exchanger in tank 4 may comprise fins of convoluted wire and an internal wire brush-like element to assist heat transfer. <IMAGE>

Description

SPECIFICATION Improvements in domestic hot water systems This invention relates to an improved hot water system primarily for domestic purposes. The invention is concerned with hot water systems using a cylinder incorporating a coil which is fed with hot waterfrom a boiler and in which water contained within the cylinder is indirectly heated using the coil.

A disadvantage with such systems is that the heat-up of water in the cylinder is a relatively slow process due to the mass of water and it can take a considerable period of time to heat up the waterto a usable temperature.

It is an object of this invention to provide a storage tank arrangementfor hotwaterand whereinthe quantity of water may be heated much more rapidly to a usable temperature.

According to this invention there is provided a hot water tank system comprising a cylinderwith a water draw-offoutletandawater inlet and including an internal coil fed with hotwaterfrom a boiler so asto indirectly heat the quantity of water within the cylin- der, the system being characterized by a satellite water holding tank in series with the water draw-off outlet, the satellite tank incorporating a heat exchange means serially connected with the heating boiler and water coil provided within the cylinder, a by-pass valve means being provided whereby hot water may be passed through the heat exchanger of the satellitetank before passing throughthecoil within the cylinder or said heat exchanger may be by-passed.

In a preferred installation the satellitetankwill have a capacity oftwo gallons and this is heated rapidly from the water supply output of the boiler utilizing the heat exchanger. Preferably the heat ex changerwillcomprisea U-shapedtubeoffinned construction providing a large surface area to achieve rapid heating of the water in the satellite tank.

Preferably the satellite tank will be positioned above the main watercylinderand in close proximity to the water draw-off outlet.

The invention is further explained by way of an example shown in the accompanying drawings.

In the drawings: Figure 1 shows a water cylinder for a domestic supply and incorporating a satellite cylinder, Figure2 shows the satellite cylinder in side view, and Figure 3 shows the heat exchanger used within the satellite cylinder.

Referring to Figure 1 of the drawings, a domestic hot water system comprises a cylinder 1 which incorporates a coil serving to indirectly heat the water in the cylinder, the coil having an inlet2 and an outlet3 which communicates with the return feed D to the boiler or other heating source. The cylinder 1 has a cold waterfeed inlet (not shown) and a hotwater draw-off outlet A. The outlet is connected to a satellite cylinder4 and this includes an outlet B which then serves as the water supply draw-off. Within the satellitetank4 is located a finned heat exchange unit (see Figure 3) with an inlet C for connection with the hot water supply of the boiler and an outlet which connects with the input side of a changeover valve E.The valve E may be set by means of a control 5 to direct the heating water supply output from the satellite tank4eitherthrough pipe Ftothe inlet 2 ofthe coil in the cylinderorthrough pipe 6 to directlycommuni- cate with the outlet D thereby by-passing the coil.

Figure 2 shows the satellite tank4 in side view and as may be see this has an inletAwhich connects with the water draw-off on top of the cyiinder 1 and an outlet B which connects with the hot water supply to the domestic system. Located within the satellite tank4 is a heatexchange unit having an inietC and an outlet D. As shown in Figure 3, the heat exchange unit comprises a U-shaped tube 30 along the limbs of which are provided finned elements 31. Aflange 32 serves to secure the heat exchange unit within the sidewall ofthecylinder.

The satellite cylinder 4 can befitted at any point within the domestic heating draw-off, although con venientlythis will be located as shown on top of the cylinder 1. The hot waterflowfrom the boiler passes through inlet C along the heat exchangerwhereby very rapid heating of the small quantity of watercontained in tank4 is effected. The water passes from the heat exchangerthrough the outlet D to valve E wherein it may be selectively directed either through pipe F and thence inlet2tothe coil within tank 1 or, alternatively, through pipe 6 to be returned via outlet Duo the boiler.

Valve E may be operated by a manual control or by an electric motor or time clock.

Advantages ofthis arrangement are that by only heating a relatively small quantity of water consider- able costs are saved as it is unnecessary to heatthe whole contents of the cylinderwhen this is not requi- red. By heating only the contents of the satellite tank 4 a sufficient quantity of usable hot water is available within a short period,forexample 10 minutes, and usually the quantity of about two gallons is sufficient for most needs. A further advantage arises from the system according to the invention and that is where small boilers are already installed which are totally inadequateto give both hotwater and central heat ing.With arrangement described it is possible to obtain hot water via the satellite tank in a short period of time without the need for an inordinate long waitfor the contents ofthe cylinder 1 to heat up.

Afurther advantage is that were secondary solar heating devices are installed these may be fitted so that they feed the heat exchanger in the satellite tank 4 priortofeeding the coil in the cylinder 1. This then makes more efficient use of any solar heat energy extracted.

The heat exchanger is constructed with the fins 31 of convoluted wire soldered to the outside ofthe tube 30. Positioned within the tube 30 is a wire brush-like element to assist heat transfer from the fluid to the tube wall.

1. A hotwatertank system comprising a cylinder with a water draw-off outlet and a water inlet and in

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improvements in domestic hot water systems This invention relates to an improved hot water system primarily for domestic purposes. The invention is concerned with hot water systems using a cylinder incorporating a coil which is fed with hot waterfrom a boiler and in which water contained within the cylinder is indirectly heated using the coil. A disadvantage with such systems is that the heat-up of water in the cylinder is a relatively slow process due to the mass of water and it can take a considerable period of time to heat up the waterto a usable temperature. It is an object of this invention to provide a storage tank arrangementfor hotwaterand whereinthe quantity of water may be heated much more rapidly to a usable temperature. According to this invention there is provided a hot water tank system comprising a cylinderwith a water draw-offoutletandawater inlet and including an internal coil fed with hotwaterfrom a boiler so asto indirectly heat the quantity of water within the cylin- der, the system being characterized by a satellite water holding tank in series with the water draw-off outlet, the satellite tank incorporating a heat exchange means serially connected with the heating boiler and water coil provided within the cylinder, a by-pass valve means being provided whereby hot water may be passed through the heat exchanger of the satellitetank before passing throughthecoil within the cylinder or said heat exchanger may be by-passed. In a preferred installation the satellitetankwill have a capacity oftwo gallons and this is heated rapidly from the water supply output of the boiler utilizing the heat exchanger. Preferably the heat ex changerwillcomprisea U-shapedtubeoffinned construction providing a large surface area to achieve rapid heating of the water in the satellite tank. Preferably the satellite tank will be positioned above the main watercylinderand in close proximity to the water draw-off outlet. The invention is further explained by way of an example shown in the accompanying drawings. In the drawings: Figure 1 shows a water cylinder for a domestic supply and incorporating a satellite cylinder, Figure2 shows the satellite cylinder in side view, and Figure 3 shows the heat exchanger used within the satellite cylinder. Referring to Figure 1 of the drawings, a domestic hot water system comprises a cylinder 1 which incorporates a coil serving to indirectly heat the water in the cylinder, the coil having an inlet2 and an outlet3 which communicates with the return feed D to the boiler or other heating source. The cylinder 1 has a cold waterfeed inlet (not shown) and a hotwater draw-off outlet A. The outlet is connected to a satellite cylinder4 and this includes an outlet B which then serves as the water supply draw-off. Within the satellitetank4 is located a finned heat exchange unit (see Figure 3) with an inlet C for connection with the hot water supply of the boiler and an outlet which connects with the input side of a changeover valve E.The valve E may be set by means of a control 5 to direct the heating water supply output from the satellite tank4eitherthrough pipe Ftothe inlet 2 ofthe coil in the cylinderorthrough pipe 6 to directlycommuni- cate with the outlet D thereby by-passing the coil. Figure 2 shows the satellite tank4 in side view and as may be see this has an inletAwhich connects with the water draw-off on top of the cyiinder 1 and an outlet B which connects with the hot water supply to the domestic system. Located within the satellite tank4 is a heatexchange unit having an inietC and an outlet D. As shown in Figure 3, the heat exchange unit comprises a U-shaped tube 30 along the limbs of which are provided finned elements 31. Aflange 32 serves to secure the heat exchange unit within the sidewall ofthecylinder. The satellite cylinder 4 can befitted at any point within the domestic heating draw-off, although con venientlythis will be located as shown on top of the cylinder 1. The hot waterflowfrom the boiler passes through inlet C along the heat exchangerwhereby very rapid heating of the small quantity of watercontained in tank4 is effected. The water passes from the heat exchangerthrough the outlet D to valve E wherein it may be selectively directed either through pipe F and thence inlet2tothe coil within tank 1 or, alternatively, through pipe 6 to be returned via outlet Duo the boiler. Valve E may be operated by a manual control or by an electric motor or time clock. Advantages ofthis arrangement are that by only heating a relatively small quantity of water consider- able costs are saved as it is unnecessary to heatthe whole contents of the cylinderwhen this is not requi- red. By heating only the contents of the satellite tank 4 a sufficient quantity of usable hot water is available within a short period,forexample 10 minutes, and usually the quantity of about two gallons is sufficient for most needs. A further advantage arises from the system according to the invention and that is where small boilers are already installed which are totally inadequateto give both hotwater and central heat ing.With arrangement described it is possible to obtain hot water via the satellite tank in a short period of time without the need for an inordinate long waitfor the contents ofthe cylinder 1 to heat up. Afurther advantage is that were secondary solar heating devices are installed these may be fitted so that they feed the heat exchanger in the satellite tank 4 priortofeeding the coil in the cylinder 1. This then makes more efficient use of any solar heat energy extracted. The heat exchanger is constructed with the fins 31 of convoluted wire soldered to the outside ofthe tube 30. Positioned within the tube 30 is a wire brush-like element to assist heat transfer from the fluid to the tube wall. CLAIMS

1. A hotwatertank system comprising a cylinder with a water draw-off outlet and a water inlet and in cluding an internal coil fed, in use, with hotwater from a boilers as to indirectly heat the quantity of water within the cylinder, the system being characterized by a water holding tank in series with the water draw-off outlet, the holding tank incorporating a heat exchange means serially connected with the heating boiler and water coil provided within the cylinder, a by-pass valve means being provided whereby hot water may be passed through the heat exchanger of the holding tank before passing through the coil within the cylinder or said heat exchanger may be by-passed.

2. A hot water tank system as claimed in claim 1, wherein the holding tank has a capacity of about 10 litres.

3. A hotwater tank system as claimed in claim 1 or 2, wherein the heat exchanger comprises a finned U-shapedtubeto provide a large heat exchange area.

4. A hotwatertank system as claimed in any preceding claim, wherein the holding tank is located on top ofthe cylinder.

5. A hot watertank system as claimed in any preceding claim, wherein the by-pass valve is located on top of the cylinder.

6. A hotwatertank system as claimed in any preceding claim, wherein the by-pass valve is operated either manually, by electric drive or by a time clock.

7. A hotwater tank system as described herein or as exemplified by the description and the drawings.

8. A dwelling incorporating the system of any preceding claim.