EP2773908A1

EP2773908A1 - Domestic hot water distribution device

Info

Publication number: EP2773908A1
Application number: EP12778751.3A
Authority: EP
Inventors: Pascal NUTI
Original assignee: Quantia Sas
Current assignee: Quantia Sas
Priority date: 2011-11-02
Filing date: 2012-10-31
Publication date: 2014-09-10
Also published as: WO2013064528A1; FR2982012A1; JP2015501412A; US20140338754A1; BR112014010687A2; FR2982012B1; CN104024741A

Abstract

The invention relates to a domestic hot water distribution device including a feed water intake, a wastewater collector, and means (10, 20) for heating the feed water in order to produce domestic hot water using heat contained in wastewater, the heating means comprising thermoelectric modules (25) designed to transfer heat from the wastewater to the feed water to be heated, characterized in that the heating means (10, 20) include at least one first heat exchanger (10) designed to simultaneously carry out a first transfer of heat for the distribution of hot water and from the wastewater to the feed water, thereby resulting in a temperature difference that is lower than a predetermined difference, and in that the thermoelectric modules (25) are arranged downstream from the first heat exchanger in a second heat exchanger (20), which simultaneously carries out a second transfer of heat for the distribution of hot water and from the wastewater to the feed water.

Description

D I S D I D I D I D I STR I B ION WATER UTILITY HEALTHCARE

The present invention generally relates to domestic hot water dispensing apparatus incorporating heat recovery from the heat of wastewater.

It is known in the prior art hot water distribution devices incorporating a heat recovery device, such as that described for example in the document US 4,821,793. This document discloses a shower comprising a water-to-water heat exchanger with a coil. to recover energy from wastewater. In return, this system has the particular disadvantage of being bulky and inefficient to recover a large amount of heat.

Furthermore, the document US2009242005A1 discloses a dishwasher equipped with Peltier modules for heating the cleaning water of the dishwasher. This system is not suitable for domestic hot water production due to the temperature ranges involved. Indeed, in a dishwasher, the water is heated up to 85 ° C, which is totally incompatible with the use for a shower for example. This results in a significant loss of efficiency and should even provide a cooling water produced by this system to use the water for sanitary purposes.

FR 2 486 060 discloses a wastewater treatment plant of a dwelling with a heat recovery unit.

An object of the present invention is to meet the drawbacks of the documents of the prior art mentioned above and in particular, first of all, to provide a device for producing domestic hot water and offering a recovery efficiency of important energy.

For this purpose, a first aspect of the invention relates to a hot water dispensing device comprising a supply water inlet, a wastewater collector and means for heating the feedwater to produce water. domestic hot water from heat contained in waste water, characterized in that the means of heating comprise thermoelectric modules arranged to operate a heat transfer from the wastewater to the feed water to be heated. The device according to the invention offers an economical and compact solution for recovering heat in the wastewater by using thermoelectric modules as a heat pump. The domestic hot water is delivered at a temperature between 35 ° C and 60 ° C.

Advantageously, the heating means comprise at least a first heat exchanger arranged to operate from the wastewater to the feedwater a first heat transfer resulting in a difference in temperature below a predetermined difference, and in that that the thermoelectric modules are arranged downstream of the first heat exchanger in a second heat exchanger operating from the wastewater to the feedwater a second heat transfer. The present invention judiciously uses a first heat exchanger to create predetermined and favorable conditions for the operation of the second heat exchanger comprising the thermoelectric modules. The heat exchanges are concomitant with the distribution of hot water to recover heat loop. In other words, the distributed hot water is recovered and forms the wastewater which passes into the first exchanger arranged to transfer, during the distribution of hot water, a portion of the heat contained in the wastewater to the feed water. Thus, the first exchanger performs a first heating of the feedwater, simultaneously with the hot water supply, to deliver to the second exchanger comprising the thermoelectric modules of the feed water and wastewater with a difference in temperature. reduced temperature. This reduced temperature difference makes it possible to place the thermoelectric modules of the second heat exchanger in an advantageous operating range as a heat pump consuming little electric current, to effect the second heat transfer. The cold supply water is heated only with these two heat exchanges, before being distributed as domestic hot water. Advantageously, the first heat exchanger delivers to the second heat exchanger waste water and a feed water having a temperature difference of 20 ° C maximum. Ideally, the temperature difference between wastewater and feed water is 15 ° maximum. The applicant realized that this temperature range was particularly advantageous for obtaining the operation of the thermoelectric modules with a COP greater than 1.

Advantageously, the thermoelectric modules have a maximum operating temperature difference and the first heat exchanger supplies the second waste heat exchanger and a feed water having a nominal temperature difference of less than 20% of the difference in temperature. maximum operating temperature. The applicant realized that this temperature range was particularly advantageous for obtaining the operation of the thermoelectric modules with a COP greater than 1.

Advantageously, the thermoelectric modules have a maximum electric current of use and the thermoelectric modules are supplied with a nominal supply current lower than 20% of the maximum current of use. Ideally, the rated supply current is 15% of the maximum operating current. The Applicant has found that this field of use is particularly advantageous for the economical thermoelectric modules to operate with a coefficient of performance (COP) greater than 1. It can also be noted that the Joule energy losses in the thermoelectric modules will be transmitted to the feed water, which further increases the coefficient of performance.

A particularly interesting embodiment consists in that the first heat exchanger is arranged to deliver to the second heat exchanger waste water and a feed water having a temperature difference lower than the predetermined difference to place the thermoelectric modules in a field of heat. operation with a coefficient of performance (COP) greater than 1. The first exchanger according to this implementation is specially designed to operate a first heat exchange, while delivering waste water and a feed water having a maximum temperature difference that determines a particular operation of the thermoelectric modules. Indeed, the latter, used as a heat pump and if they are subject to a maximum temperature difference, will operate in a particularly advantageous operating range with a coefficient of performance (COP) greater than 1. In other words, such a COP, representing the energy supplied to the feed water by the thermoelectric modules divided by the electrical energy supplied to the thermoelectric modules, if it is greater than 1, indicates that the thermoelectric modules provide more energy to the feed water than they consume themselves. The device becomes more economical to use than a solution with a reserve of water conventionally heated by electrical resistors.

Very advantageously, the first heat exchanger is a water-water heat exchanger. This solution is economical.

Advantageously, the second heat exchanger comprises:

- a wastewater inlet and a wastewater outlet connected by at least one wastewater pipe,

a supply water inlet and a supply water outlet connected by at least one feed water pipe,

the thermoelectric modules comprising a cold face and a hot face are arranged between a wall of the wastewater pipe and a wall of the feed water pipe, the cold face being arranged to collect heat from the wastewater and the face hot being arranged to deliver heat to the feed water,

and the wastewater and feedwater conduits are arranged to minimize temperature differences between hot and cold faces along the second heat exchanger.

The arrangement of the ducts to minimize temperature differences along the second exchanger makes it possible to stay as long as possible in the preferred field of use of the thermoelectric modules.

Advantageously, the waste water and feedwater pipes are arranged to operate a countercurrent circulation in the second exchanger. This implementation makes it possible to ensure a constant temperature difference along the second exchanger comprising the thermoelectric modules, in order to maintain them in the preferred field of use.

Advantageously, the device delivers feedwater at a final temperature and comprises means for adjusting the final temperature of the feed water able to control the thermoelectric modules to adjust the final temperature of the water of the feedwater. food. The adjustment means according to the invention comprise a man-machine interface allowing the user to define the final temperature of the supply water, and depending on this final temperature, the adjustment means feed the thermoelectric modules with a current suitable for obtaining the desired end temperature.

A second aspect of the invention is a shower comprising a hot water dispensing device according to the first aspect of the invention. The integration of the device according to the first aspect of the invention in a shower is very favorable, because this compact device is entirely appropriate to operate without storing hot water, because it produces hot water only when the use of the shower. Then, thanks to the use of the thermoelectric modules in a particular operating range created by the first exchanger, the energy efficiency is good, with a COP greater than 1. It should be noted that the device according to the first aspect of the invention can be integrated in a washbasin or a sink, where the evacuation of wastewater is concomitant with the provision of hot water.

Another aspect of the invention relates to a hot water dispensing method comprising the steps of:

- distribute hot water,

- recover this hot water to form wastewater,

operating in a first heat exchanger simultaneously with the distribution of hot water, from the wastewater and to feedwater, a first heat transfer resulting in a difference in temperature below a predetermined difference, between wastewater and the feed water at the outlet of the first heat exchanger,

operating, downstream of the first heat exchanger and in a second heat exchanger with thermoelectric modules, a second transfer of heat from the wastewater to the feedwater simultaneously with the hot water distribution,

- distribute the heated feed water as hot sanitary water.

The method according to the invention allows an economical heating in the hot water distribution apparatus for which the wastewater is recovered simultaneously with the distribution, such as for example a shower or sink without water storage for example.

Advantageously, a preliminary step of priming the system is performed at the beginning of hot water distribution, and consisting of heating the feed water Joule effect with the thermoelectric modules.

Advantageously, the predetermined difference is 20 ° C maximum.

Other features and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the appended drawing, in which: - Figure 1 shows a shower equipped with a device according to the invention;

FIG. 1 represents a shower with a hot water dispensing device comprising a first heat exchanger 10 and a second heat exchanger 20. The shower comprises a shower head and a water collection tank projected by the apple shower. The wastewater is discharged through an outlet 12 and then enters the first heat exchanger 10. The latter consists for example of a tank supplied by the outlet 12 of the shower tray and in which is arranged a helical tube. The tube is supplied with cold water by a feed inlet 1 1. A first heating of cold water is operated in the first exchanger 10 by transferring part of the heat contained in the wastewater to cold water. Typically, the wastewater has a temperature between 30 and 40 ° C, and cold water between 5 and 15 ° C. The first heat exchanger is arranged so that at the outlet of the first heat exchanger, the temperature difference between the waste water at point 14 and the feed water at point 13 is less than a predetermined value, for example 20 ° C. a predetermined operating range of the second thermoelectric heat exchanger where its coefficient of performance will be greater than 1.

The second heat exchanger 20 comprises a plurality of thermoelectric modules (also called Peltier modules) 25 interposed between a waste water pipe 27 and a feed water pipe 26. The thermoelectric modules 25 comprise two main faces, one being the cold face, the other the hot face. The hot faces of each thermoelectric module are arranged in direct contact with the supply water conduit 26 and the cold faces are arranged in direct contact with the waste water conduit 27. The conduits 27 and 26 are arranged such that they operate against the current, to keep a temperature difference as constant as possible between the wastewater and the feed water. In addition, by electrically feeding the modules thermoelectric, the latter will operate as a heat pump. Ideally, the power will be with a power less than a predetermined fraction (20% for example) of the maximum power of the thermoelectric modules, in order to be in a favorable area with a coefficient of performance greater than 1. The arrangement of the first exchanger makes it possible to obtain a temperature difference between the wastewater and the feed water entering the second exchanger, placing the second exchanger in an operating range where its coefficient of performance will be greater than 1.

It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the various embodiments of the invention described in the present description without departing from the scope of the invention defined by the appended claims. In particular, reference is made to a water-water heat exchanger, it is possible to envisage using a plate, tube, tube U, horizontal or vertical tubular heat exchanger, spiral or block heat exchanger. Furthermore, one can also consider using the device according to the invention in any hot water dispensing device which comprises a discharge of hot waste water containing energy, continuous and concomitant with the supply of hot water.

Claims

R EV IN DI CATI ON S

1. Sanitary hot water distribution device comprising a feedwater inlet, a wastewater collector and means (10, 20) for heating the feed water to produce domestic hot water at from heat contained in wastewater, the heating means comprising thermoelectric modules (25) arranged to effect a transfer of heat from the wastewater to the feedwater to be heated, characterized in that the heating means ( 10, 20) comprise at least a first heat exchanger (10) arranged to operate, simultaneously with the hot water distribution and from the wastewater to the feedwater, a first heat transfer resulting in a difference in temperature. temperature below a predetermined difference, and in that the thermoelectric modules (25) are arranged downstream of the first heat exchanger in a second heat exchanger (20) operating simultaneously with the distribution of hot water and from the wastewater to the feed water, a second heat transfer.

2. Domestic hot water dispensing device according to claim 1, characterized in that the first heat exchanger (10) is arranged to deliver to the second heat exchanger (20) waste water and a feed water having a temperature difference of 20 ° C maximum.

3. Domestic hot water dispensing device according to one of claims 1 or 2, characterized in that the thermoelectric modules (25) have a maximum electric current of use and in that the thermoelectric modules (25) are arranged to be supplied with a nominal supply current of less than 20% of the maximum operating current.

4. Domestic hot water dispensing device according to one of claims 1 to 3, characterized in that the first heat exchanger (10) is arranged to deliver to the second heat exchanger (20) waste water and a water power supply having a temperature difference smaller than the predetermined difference for placing the thermoelectric modules (25) in an operating range with a coefficient of performance (COP) greater than 1.

5. Domestic hot water dispensing device according to one of claims 1 to 4, characterized in that the first heat exchanger (10) is a water-water heat exchanger

6. Domestic hot water dispensing device according to one of claims 1 to 5, characterized in that the second heat exchanger (20) comprises:

- a wastewater inlet (27a) and a wastewater outlet (27b) connected by at least one waste water pipe (27),

a supply water inlet (26a) and a feed water outlet (26b) connected by at least one feed water pipe (26),

in that the thermoelectric modules (25) having a cold face and a hot face are arranged between a wall of the waste water pipe (27) and a wall of the feed water pipe (26), the cold face being arranged to collect heat from the wastewater and the hot face being arranged to deliver heat to the feedwater,

and in that the wastewater (27) and feedwater (26) conduits are arranged to minimize temperature differences between the hot and cold faces along the second heat exchanger (20).

7. Domestic hot water distribution device according to claim 6, characterized in that the waste water pipes (27) and feed water (26) are arranged to operate a countercurrent circulation.

8. Shower comprising a hot water dispensing device according to one of claims 1 to 7.

9. A method of dispensing domestic hot water comprising the steps of:

- distribute hot water,

- recover this hot water to form wastewater,

operating in a first heat exchanger (10) simultaneously with the distribution of hot water, from the wastewater and to feed water, a first heat transfer resulting in a difference in temperature lower than a predetermined difference between the wastewater and the feedwater at the outlet of the first heat exchanger (10),

operating, downstream of the first heat exchanger and in a second heat exchanger (20) with thermoelectric modules (25), a second transfer of heat from the wastewater to the feed water simultaneously with the distribution of Hot water,

- distribute the heated feed water as hot sanitary water.

10. The method of claim 9 wherein a preliminary step of priming the system is performed at the beginning of hot water distribution, and consisting of heating the feed water Joule effect with the thermoelectric modules (25).

1 1. Method according to one of claims 9 or 10, wherein the predetermined difference is 20 ° C maximum.