GB2537964A

GB2537964A - A hot water tank device with a jacket provided with a heat exchanger

Info

Publication number: GB2537964A
Application number: GB1603196.5A
Authority: GB
Inventors: Radulescu Mihai
Original assignee: Electricite de France SA
Current assignee: Electricite de France SA
Priority date: 2015-02-24
Filing date: 2016-02-24
Publication date: 2016-11-02
Also published as: GB201603196D0; FR3033033A1

Abstract

A hot water tank device comprises a hot water storage volume (1) and a means (11) for heating water contained in this volume. The storage volume (1) comprises a hot water outlet (12) and an outer heat insulation layer (17). An external jacket (18) surrounds the layer (17) and is configured for containing water and in thermal communication with said heat insulation layer (17) in order to recover the heat energy issued from said insulation layer (17). The heat exchanger (20, 30) is positioned inside the external jacket (18) and in that the inlet of said heat exchanger is connected to a sanitary cold water supply so that the heat energy issued from the water contained in said jacket (18) is recovered to warm the water circulating inside said heat exchanger.

Description

GENERAL TECHNICAL FIELD

The invention is Located in the field of hot water tank devices. The present invention more specifically relates to a hot water tank 5 device comprising a volume for storing hot water, means for heating the water contained in this volume, an outer heat insulation layer of this volume and an external jacket capable of containing water and which is in thermal communication with said heat insulation layer of the tank.

The invention also relates to a method for refurbishing an existing 10 hot water tank.

STATE OF THE ART

A water heater device is already known according to document 15 FR 2 953 000, as illustrated in the appended Figure 1.

This device comprises a volume for storing hot water 1 and means 11 for heating the water contained in this volume. Further, this volume 1 is connected to a hot water outlet 12, generally connected to a circuit for using sanitary hot water 13 on the one hand and to a cold water inlet 14, itself connected to a cold water supply 15, on the other hand.

The storage volume 1 is delimited by a wall 16, surrounded by an outer thermal insulation layer 17 (consisting of a suitable insulation material), so that the energy consumed for heating the water via the heating means 11 is not rapidly Lost by thermal dissipation of the wall 16 of the hot water storage volume 1.

Further, in order to further improve the recovery of the heat losses of the storage volume 1, the thermal insulation layer 17 is itself surrounded with an insulating jacket 18, filled with water and in thermal communication with the layer 17.

The jacket 18 is connected, preferably at its Low portion, to a cold water inlet 181, itself connected to the cold water supply 15.

Further, the jacket 18 is also connected, preferably at its high portion, to a water outlet 182, itself connected to a mixing valve 19, arranged on the hot water outlet 12 of the storage volume 1.

The water contained in the jacket 18 thus allows recovery of the residual heat losses from the storage volume 1 in spite of the existence of an insulation Layer 17. The thereby warmed-up water is then mixed with the hot water leaving the volume 1, which allows an increase in the overall yield of the water heater.

However, this device of the state of the art has the drawback that 10 the jacket 18 has to resist to the pressure of the cold water supply network, which may attain at most 7 bars (7.105 Pa). Consequently, such a jacket should be made in a material resisting such pressures, so that it is relatively expensive. Consequently, the overall financial savings made by the recovery of the residual heat losses is modest.

The document EP0062728 describes a heating system comprising a volume for storing hot water and means for heating the water contained in this volume, said means being a coil wherein freon gas circulates. The storage volume (water heater 4) is surrounded from the inside to the outside by a first jacket 15 forming a heat exchanger and by a second jacket 2 forming an evaporator.

Nevertheless, the water contained in the evaporator 2 is preheated by an outside source (for example by earth heat) and is used to warm the freon circulating in the coil disposed in said evaporator 2. This freon is then returned in the coil disposed inside the water heater 4.

This device does not allow recovering the residual heat losses of 25 the hot water storage volume.

PRESENTATION OF THE INVENTION

The object of the invention is therefore to solve the aforementioned drawbacks of the state of the art. It notably has the goal of providing a hot water tank device which, while allowing recovery of the residual heat Losses of the hot water storage volume, is resistant to the pressure of the cold water supply network and this, without significantly increasing the costs.

For this purpose, the invention relates to a hot water tank device comprising a hot water storage volume, means for heating the water contained in this volume, this storage volume comprising a hot water outlet and an outer heat insulation layer, the device further comprising an external jacket, which surrounds said outer heat insulation layer and which is configured for containing water and for being in thermal communication with said thermal insulation layer, in order to recover heat energy issued from the storage volume which passes through said insulation layer and which is issued therefrom to warm up the water contained in said external jacket.

According to the invention, this device comprises a heat exchanger positioned inside said external jacket and the inlet of said heat exchanger is connected to a sanitary cold water supply, so that the heat energy issued from the water contained in said jacket is recovered to warm the water circulating inside said heat exchanger.

According to other advantageous and non-limiting features of the invention, taken alone or as a combination: the outlet of the heat exchanger is connected to said storage volume; - the outlet of the heat exchanger is connected, via a mixing valve to the hot water outlet of the storage volume; the mixing valve is controlled by a control unit comprising at the input, information relating to the temperature of the contained water or leaving said storage volume and/or information relating to the temperature of the water contained in or leaving said heat exchanger; - the heat exchanger is a coil in a good heat conducting material, such as metal; the heat exchanger is a tube with fins in a good heat conducting material, such as metal; the heat exchanger is a panel-shaped exchanger; - the heat exchanger is positioned at least partly in the upper portion of the jacket which extends above the storage volume; and the jacket is provided with an inlet, preferably located at its upper portion; the jacket comprises a membrane which forms the envelope of the jacket and within which is contained the water of the jacket, this membrane being water proof and sufficiently flexible for fitting the shape of the heat insulation layer.

The invention also relates to a method for refurbishing a hot water tank device which comprises a hot water storage volume, means for heating the hot water contained in this volume, this volume comprising a hot water outlet, and being surrounded by an outer heat insulation layer, this method comprising the following steps: setting into place on the outside of said heat insulation layer a jacket configured for containing water, this jacket being in thermal communication with said heat insulation layer and containing a heat exchanger, filling the jacket with water, connecting the inlet of this heat exchanger to a sanitary cold water supply and connecting the outlet of this exchanger either to said water storage volume, or to a circuit for using sanitary hot water, preferably via a mixing valve itself connected to the hot water outlet of said storage volume.

PRESENTATION OF THE FIGURES

Other features and advantages of the invention will become apparent from the description which will now be made thereof, with reference to the appended drawings, which illustrate, as an indication but not as a limitation, various possible embodiments.

In these drawings: Fig. 1 is a schematic illustration of a hot water tank device according to the state of the art, Fig. 2 is a schematic illustration of a hot water tank device according to a first embodiment of the present invention, Fig. 3 is a schematic illustration of the heat exchanger of the hot water tank device along a cross-sectional plane illustrated by the line III-Ill in Fig. 2, Fig. 4 is a schematic illustration of a hot water tank device according to another possible embodiment of the present invention, and

S

-Fig. 5 is a perspective view of another embodiment of the heat exchanger of the hot water tank device according to the invention.

DETAILED DESCRIPTION

A first embodiment of the hot water tank according to the invention will now be described with reference to Fig. 2. The elements common with the known device of the state of the art, and described previously with reference to Fig. 1, bear the same numerical references.

This device comprises a hot water storage volume 1, in which are laid out means 11 for heating the water contained in said storage volume. The heating means 11 may be of any nature from the moment that they give the possibility of providing heat energy to the water contained in the volume 1 in order to heat it. As a non-limiting example, these heating means 1 may be electrical (electric resistor), hydraulic (coil in which flows a heat transfer fluid heated by a gas, fuel or wood boiler, for example, or by a heat pump or by any other heat source), solar (coil in which flows a heat transfer fluid heated by a solar sensor or panel).

The term of "storage volume" 1 refers to the hot water tank itself, 20 delimited by a wall 10. This volume 1 is surrounded by an insulation layer 17.

The hot water storage volume 1 is generally of a cylindrical geometry with a circular or substantially circular cross-section. However, any other geometry may be used without however departing from the scope of the invention.

The outer insulation layer 17 is made in any material giving the possibility of achieving heat insulation between the water contained in the storage volume 1 and the outside of the device.

Such a heat insulation layer 17 is well known from the state of the art and will not be described in more detail.

The storage volume 1 also comprises a hot water outlet 12, for example connected to a network for using sanitary hot water 13.

Preferably, the hot water outlet 12 opens into the upper portion of the storage volume 1, where the hottest water is found.

The jacket 18 is both capable of containing water and of being in 35 thermal communication with the heat insulation layer 17.

Accordingly, this jacket 18 is advantageously made in any type of material allowing absorption of the heat energy issued from the insulation layer 17, in order to be able to heat the water which is found inside this jacket.

The jacket 18 also has a geometry such that it may be adapted to 5 the hot water volume 1, more specifically to the contour of the outer walls 10 of the insulation layer 17.

Advantageously, the jacket 18 comprises a membrane 183 which forms the envelope of the jacket and within which is contained the water of the jacket.

Advantageously, this membrane 183 is both waterproof, sufficiently flexible for fitting the shape of the heat insulation layer 17, resistant to puncture and to tearing, and, finally adherent to metals and/or to plastic materials, so as to allow its attachment on the outside of the insulation layer 17. Advantageously, the membrane 183 is made in a material having 15 good resistance to flexure and traction, as well as good ageing.

Preferably, the membrane 183 of the jacket is made in an elastomeric material or in a thermoplastic material, such as for example polypropylene or flexible PVC, the properties of which are close to those of elastomers.

The jacket 18 is provided with a water inlet 187, with a closing plug, preferably located at the high portion 185 of the jacket. The filling of the jacket 18 is thus accomplished through this inlet 187 by gravity without using the cold water network in order to not cause a rise of pressure in the jacket.

Also preferably, the jacket 18 is provided with an emptying device 25 184, preferably located at its low portion, in order to proceed with the discharge of the water contained in the jacket, if necessary.

As explained earlier, the water contained in the jacket 18 is warmed up by means of the heat Losses from the heat which passes through the heat insulation layer 17.

According to the invention, a heat exchanger is positioned inside said external jacket 18.

According to a first embodiment of the invention, this heat exchanger is tubular and bears the numerical reference 20.

According to a first alternative embodiment, the tubular heat 35 exchanger 20 consists of a coil made in a thermally good heat conducting material, for example in copper, positioned between the membrane 183 and the heat insulation layer 17.

Preferably, the coil 20 circulates in the upper portion 185 of the jacket 18, i.e. the one which extends above the volume 1 covered with the insulator layer 17. This portion 185 also corresponds to the area of the jacket 18, in which is found the water at the highest temperature, considering the Layering of the water in the jacket. This particular arrangement of the coil 20 is illustrated in Fig. 3.

However, it will be noted that the coil 20 may also partly or totally 10 extend in the vertical annular portion 186 of the jacket which surrounds the volume 1 over the whole of its height.

The tubular exchanger 20 has a cold water inlet 201 connected to the sanitary cold water supply 15 and a sanitary water outlet 202. In the embodiment illustrated in Fig. 2, this outlet 202 is connected to the inside of the 15 storage volume 1, preferably at the Low portion of the latter.

According to the alternative embodiment not shown in the figures, the tubular heat exchanger 20 may also be a coil in a good heat conducting material, surrounded with fins which further increase its heat exchange surface area.

The heat exchange is carried out between the water contained in the jacket 18 and the sanitary cold water circulating in the coil 20, so that the water contained in the jacket 18 transfers calories to the water circulating in the coil 20. The heat exchanger 20 thus gives the possibility of pre-heating the water which it contains before introducing it inside the volume 1.

According to another alternative embodiment, illustrated in Fig. 5, the heat exchanger may be a panel formed with two plates in thermally good conducting materials, for example in metal, for example in aluminium, welded together, except for delimiting a circuit 300, for example coil-shaped, inside which the sanitary cold water may circulate. Such a heat exchanger is referenced as 30. For example it may be made by a process known under the brand of Roll-Bond.

This exchanger 30 is advantageously positioned in the upper portion 185 of the jacket 18.

Its inlet 301 is connected to the sanitary cold water supply 15, 35 whereas its outlet 302 is for example connected to the inside of the storage volume 1.

The exchanger 20, 30 is further designed for resisting the strong pressures prevailing inside the sanitary cold water supply network 15 and which may attain 7 bars (7.105 Pa).

A second embodiment of the invention will now be described with 5 reference to Fig. 4. The elements common to the hot water tank device of Fig. 2 bear the same numerical references and will therefore not be described again in detail.

This hot water tank device differs from the previous one in that the storage volume 1 comprises a cold water inlet 14, connected to the cold 10 water supply 15, this inlet 14 preferably being located at the lower portion of the volume 1.

The device also differs from that of Fig. 2 in that the hot water outlet 12 is connected to the circuit for the use of sanitary hot water 13, via a mixing valve 3, and finally in that the outlet 202 or 302 of the heat exchanger 20, 15 respectively 30, is also connected to this mixing valve 3.

The mixing valve 3 is thus supplied with hot water from the storage volume 1 and with the pre-heated water issued from the heat exchanger 20 or 30.

Advantageously, the mixing valve 3 is driven by a control unit 4, 20 such as for example a computer, via means for transmitting information 45 which may be wired, wireless or any other known means of the state of the art. Advantageously, the control unit 4 receives, at the input, a piece of information relating to the temperature of the water contained or Leaving the heat exchanger 20, 30. To do this, a temperature sensor 41 is placed on the 25 output 202, respectively 302 or in any point of the heat exchanger 20, respectively 30. This temperature sensor 41 is connected to the control unit 4 through a means for transmitting information 42.

Advantageously, a temperature sensor 43 may also be positioned either on the outlet 12 of the storage volume (as illustrated in Fig. 4), or inside this storage volume 1. The temperature sensor 43 is connected to the control unit 4 through a means for transmitting information 44. The means for transmitting information 42, 44 may be wired, wireless or any other known means of the state of the art.

Depending on information relating to the desired temperature at 35 the network for using sanitary hot water 13, the control unit 4 drives the mixing valve 3, so that the latter adds to the water from the hot water outlet 12, one or more or less great amount of water from the heat exchanger 20, respectively 30. This is possible since the temperature of the hot water produced by the hot water tank is generally higher (for example close to 60°C), than the 5 temperature of the sanitary hot water from the heat exchanger 20, 30, which generally is at most 30°C for example. As a purely illustrative example, for a tank of 300 liters, it is possible to use a jacket containing between 3 and 20 liters and a tubular exchanger with a capacity ranging from 0.2 liter to 4 Liters.

Advantageously, it will be noted that the hot water tank device according to the invention and which has just been described, may be adapted to the refurbishing of existing hot water tanks which comprise a hot water storage volume, means for heating the hot water contained in this volume, a hot water outlet, and an outer heat insulation layer.

Such a refurbishing method then comprises the following steps: -setting into place on the outside of said heat insulation layer 17 a jacket 18 provided with exchanger 20, 30, -filling the jacket 18 with water, -connecting the inlet 201, 301 and the outlet 202, 302 of the exchanger 20, 30 to the sanitary cold water supply 15 and either to the volume 1, or to the circuit 20 13, respectively, preferably via the mixing valve 3.

Claims

CLAIMS1. A hot water tank device comprising a volume for storing hot water (1), means (11) for heating the water contained in this volume, this storage volume (1) comprising a hot water outlet (12) and an outer heat insulation layer (17), the device further comprising an external jacket (18), which surrounds said outer heat insulation layer (17) and which is configured for containing water and for being in thermal communication with said heat insulation layer (17), in order to recover the heat energy issued from the storage volume (1) which passes through said insulation Layer (17) and which is issued therefrom to warm up the water contained in said external jacket (18), characterized in that it comprises a heat exchanger (20, 30) positioned inside said external jacket (18) and in that the inlet (201, 301) of said heat exchanger (20, 30) is connected to a sanitary cold water supply (15), so that the heat energy issued from the water contained in said jacket (18) is recovered to warm the water circulating inside said heat exchanger (20, 30).
2. The device according to claim 1, characterized in that the outlet (202, 02) of the heat exchanger (20, 30) is connected to said storage volume (1).
3, The device according to claim 1, characterized in that the outlet (202, 302) of the heat exchanger (20, 30) is connected, via a mixing valve (3) to the hot water outlet. of the storage volume (1).
4. The device according to claim 3, characterized in that the mixing valve (3) is controlled by a control unit (4) comprising at the input information relative to the temperature of the water contained or leaving said storage volume (1) and/or information relative to the temperature of the water contained or leaving said heat exchanger (20, 30).
5, The device according to one of the preceding claims, characterized in that the heat exchanger (20) is a coil in a good heat conducting material, such as metal.
6. The device according to one of claims I to 4, characterized in that the heat exchanger (20) is a tube with fins in a good heat conducting material, such as metal,
7. The device according to one of claims 1 to 4, characterized in that the heat exchanger (30) is a panel-shaped exchanger.The device according to one of the preceding claims, characterized in that the heat exchanger (20, 30) is at least partly positioned in the upper portion (185) of the jacket (18) which extends above the storage volume (1).9. The device according to one of the preceding claims, characterized in that the jacket (18) is provided with an inlet (187), preferably located in its upper portion (185).10. The device according to one of the preceding claims, characterized in that the jacket (18) comprises a membrane (183) which forms the envelope of the jacket (18) and within which is contained the water of the jacket (18), this membrane (183) being water proof and sufficiently flexible for fitting the shape of the heat insulation layer (17).11.A method for refurbishing a hot water tank device which comprises a hot water storage volume (1), means (11) for heating the hot water contained in this volume, this volume (1) comprising a hot water outlet (12), and being surrounded by an outer heat insulation layer (17), this method being characterized in that it comprises the following steps: -setting into place on the outside of said heat insulation Layer (17) a jacket (18) configured for containing water, this jacket (18) being in thermal communication with said heat insulation layer (17) and containing a heat exchanger (20, 30), -filling the jacket (18) with water, connecting the inlet (201, 301) of this heat exchanger (20, 30) to a sanitary cold water supply (15) and connecting the outlet (202, 302) of this exchanger either to said water storage volume (1), or to a circuit for using sanitary hot water (13), preferably via a mixing valve (3) itself connected to the hot water outlet (12) of said storage volume (1).