WO2022124952A1

WO2022124952A1 - A heat exchanger for a drain compartment, and a heat exchanger system

Info

Publication number: WO2022124952A1
Application number: PCT/SE2020/051174
Authority: WO
Inventors: Sture HEDELIN
Original assignee: Idéhuset Gasellen I Varberg Ab
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2022-06-16
Also published as: EP4256242A1; SE2350865A1

Abstract

The present invention relates to a heat exchanger (200), preferably for installation in a drain compartment and comprising a heat exchanger portion (240) and a connector (230) comprising an inlet (236) and an outlet (237). The heat exchanger portion (240) and the connector (230) are arranged rotatable around a rotation axis (232) such that the heat exchanger portion and the connector are rotatable from a first position to a second position.

Description

^°^A⁴i⁹⁵²EXCHANGER FOR A DRAIN CO^K^Yy^ T,

AND A HEAT EXCHANGER SYSTEM

TECHNICAL FIELD

The present invention relates to the field of heat exchangers in general and to a heat exchanger for recovering heat from wastewater, in particular.

BACKGROUND

With the increasing demands for energy efficient buildings and resource-efficient housing developments have been made to overcome energy consumption including of both transmission losses through the building shell, and by losses through ventilations.

Energy losses for consumed water, where energy is lost to the drain, is difficult to handle and has previously been negligible part of the total energy loss. Consequently, there is also a need for reduction of losses caused by water consumption. Some attempts have been made in this area in the form of low-flush showers, taps and toilets as well as insulation of installations, etc.

There are a number of solutions with varying problems either purely technical or in efficiency terms. Heat exchangers for placement as a floor in the shower where the inlet water, pressurized tap water (household water), is exchanged for outlet water faces problems with installation and cleaning, as well as approval in accordance with industry and construction requirements.

As mentioned, most of the energy to heat the domestic hot water is wasted through the drain. It is important to handle this hot wastewater, which accounts for about 20% of the energy consumption in a home.

To recover heat, normally a heat exchanger is arranged in the path of the wastewater. Products that directly recover heat from the shower water have not yet hit the market in a desired manner. This may be due to difficulty to install, inefficiency or difficulty to clean, especially the heat exchanger part, drain compartment and its water trap. Many heat exchangers are difficult to maintain because of one or several of cleaning, decalcifying, or controlling functionality. Moreover, depending on the structure and construction material the efficiency can be varied.

Additionally, in many existing systems and solutions, the heat exchangers have a separate pressurized water circuit. This means that the heat exchangers must be designed to be stable in terms of strength in accordance with this pressure load and the intended normative usage period, which either requires relatively complex geometrical designs with low material requirements and high manufacturing costs or relatively simple constructions with low manufacturing costs.

SUMMARY

The present invention solves the above-mentioned problems.

According to one aspect of the invention an efficient and robust system, comprising a tap water portion and a heat exchange portion, is provided.

According to a second aspect of the invention the system is exposed to a low-pressure load, which is same as the (household) pipeline pressure.

According to a third aspect of the invention, other objects of the invention may include providing a heat exchanger that is at least: efficient; easy to clean and maintain; easy to assemble and install; and safe to use and avoids leakage.

According to the invention, the objectives are achieved by a heat exchanger for installation in a drain compartment and comprises a heat exchanger portion and a connector comprising an inlet and an outlet. The heat exchanger portion and the connector are arranged rotatable around a rotation axis such that the heat exchanger portion and the connector are rotatable from a first position to a second position. This allows for easy access to the space beneath for cleaning, assembly, and detecting and avoiding leakage. In one embodiment the inlet is configured to be connected to a cold-water feed to the heat exchanger and the outlet is configured to be connected to an inlet of a water mixer. This allows the system to be exposed to a low-pressure load. According to one embodiment, the heat exchanger portion is configured such that a cold-water flow in one direction and a wastewater, to affect the cold-water temperature in an opposite direction. This allows for an efficient heat exchanger.

According to one embodiment, the heat exchanger comprises a channel with a feed point for the cold-water and a return point for heated water. In one embodiment, the channel is formed as a continuous spiral loop with a height difference between the feed point and the return point, were the return point is higher than the feed point. In one embodiment, the channel may be formed as inclined tubes.

In one embodiment, the heat exchanger portion is made of pressed sheet of stainless steel, plated copper, aluminum, compressed copper pipes or extruded aluminum. In yet another embodiment, the heat exchanger portion may be made by joining upper and lower portions such that a channel system for the cold-water is shaped there between.

According to one exemplary design, the heat exchanger is configured to be connected to a water mixer, whereby the inlet is connected to cold water of the water mixer and return outlet is connected to a hot-water inlet of the water mixer.

The invention also relates to a heat exchanger system to heat cold-water by means of heat from wastewater. The system comprises: a heat exchanger configured to be arranged in a drain compartment; a mixer for providing cold-water from a cold-water source and receive water with altered temperature. The heat exchanger comprises: a heat exchanger portion comprising: a number of channels for circulating the cold-water from the mixer; and an outer surface covering the channels for distributing the wastewater at least on one surrounding surface. The heat exchanger further comprises a connector configured to receive the cold-water from the mixer and to connect to the heat exchanger portion, and return water with changed temperature to the hot water of the mixer. The heat exchange portion is arranged rotatable around a rotational axis, allowing the heat exchanger portion to rotate from a first resting position to a second raised position. The heat exchanger system may be used in a shower, bathtub or sink. In one embodiment of the heat exchanger system, the heat exchanger portion may be configured such that a cold-water to be heated flows in one direction and wastewater in an opposite direction. In one embodiment, the heat exchanger system comprises a channel with a feed connection for the cold-water and a return connection for the heated water connected to the channel, which is formed as a continuous spiral loop with a height difference between the feet point and the return point. In one embodiment, the channel may be formed as inclined tubes. In one embodiment, the heat exchanger portion may be made of pressed sheet of stainless steel, plated copper, aluminum, compressed copper pipes or extruded aluminum. In yet another embodiment, the heat exchanger portion may be made by joining upper and lower portions such that a channel system for the first medium is shaped there between, according to one embodiment, the feed connection and return connection comprise one or several of quick connection, hose connection, welding, or a seal. This allows for easy installation. In yet another embodiment, the heat exchanger portion may comprise through channels for guiding wastewater from one surface to the opposite surface.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference is made to the attached drawings, wherein the same reference numbers in different drawings may identify the same or similar elements.

Fig. 1 is a very schematically illustrated shower area, in which an exemplary system according to the present invention is installed;

Fig. 2 illustrates a schematic view of a heat exchanger and floor drain, in perspective, according to one exemplary embodiment of the present invention,

Fig. 3 illustrates a schematic cross-sectional view of the heat exchanger according to Fig. 2;

Fig. 4 illustrates in perspective a schematic view of the heat exchanger of Fig. 2 in an open, raised position;

Fig. 5a illustrates a schematic embodiment of a connector of the heat exchanger from above;

Figs. 5b and 5c illustrate schematically cross-sectional views through the connector of Fig. 5a;

Fig. 6a illustrates a schematic view from above of a heat exchanger portion according to one embodiment of the present invention;

Fig. 6b illustrates schematically a cross-sectional view through the heat exchanger portion of Fig. 6a and a partial magnification; Fig. 7 illustrates an elevated and schematic view of a heat exchanger portion according to a second embodiment of the present invention;

Fig. 8 illustrates an elevated and schematic view of a heat exchanger portion according to a third embodiment of the present invention;

Fig. 9 illustrates in perspective a schematic view of another embodiment of the heat exchanger; and

Fig. 10 illustrates a schematic cross-sectional view of a mixer according to one embodiment of the present invention.

DETAILED DESCRIPTION

In the following, schematic examples of the invention are provided with reference to a shower. However, the invention is not limited to showers and may, with advantage, be used in bathtubs, sinks (kitchen, utility room), or anywhere it is possible to recover heat from a flowing medium with higher temperature and transfer the heat to another medium with lower temperature, or vice versa.

The term “heat exchanger”, as used herein, may refer to a device used to transfer heat between two or more fluids, i.e. to increase or decrease temperature of at least one fluid under influence of another fluid. In some cases, other mediums may substitute fluids. The terms “tap water” or “household water”, as used herein may refer to running water, city water, town water, municipal water, sink water, etc. and is water supplied to a tap.

Briefly, according to the present invention, a system for heat exchanging is provided, which according to one example comprises a shower mixer and a heat exchanger located in the floor drain. According to one embodiment, the cold-water (freshwater) is directed through the shower mixer to the heat exchanger for heating (increased temperature) before it is guided back and mixed to a desired temperature with the hot water. Of course, the invention is not limited to water and other mediums temperature of which is intended to be altered may also be addressed.

The heat exchanger, arranged in the floor drain compartment (floor drain, sewer, shower well, etc.), is located above the water trap (if installed) of the drain, and do not utilities (additional) pressurized water source when not in use as the mixer stops the water flow in the shut off state, which enables a simple installation of the heat exchanger and hygienic design for accessible sanitation. The floor drain space with the heat exchanger may be rectangular in configuration and the cold-water is guided centrally into the heat exchanger, designed so that the water is led into small channels and then back to the mixer while the hot-water (wastewater) rinses over the channels on its way towards the drain/water trap.

Fig. 1 illustrates a shower area 100, comprising a floor 110, a drain 120 with a drain grate 121 (may also be a lid of the heat exchanger), a heat exchanger 200, a mixer 300, a shower 130, freshwater/cold-water pipe 140, hot-water pipe 150, feeder pipe 160, return pipe 170 and shower feed pipe 180. The shower area may be limited by walls, screens, a cabin, etc. (not shown).

Normally, the floor 110 is inclined towards the draining area and the drain 120. The water from the shower rinse over the floor to the drain or directly into the drain.

The shower 130, which may also comprise a deluge head and a hand shower, streams sprays of tempered water when a user uses flow control and temperature control of the mixer.

Underneath the drain grate 121 (or lid of heat exchanger), the heat exchanger 200 in accordance with one aspect of the invention is arranged.

Fig. 2 is a perspective view of an exemplary heat exchanger 200 according to one embodiment of the invention. The heat exchanger 200 may comprise a housing 210, a lid 220, and connector 230. The lid 220 may have smaller circumference than the opening of the housing 210 or the drain entrance and thus exhibit a slit 221 surrounding the lid 220. A drainpipe 160 connected to a water trap 161 (Fig. 3) is visible under the heat exchanger 200.

Fig. 3 is a schematic sectional view along line A-A of the heat exchanger 200 in Fig. 2.

The heat exchanger 200 comprises a housing 210, a lid 220, a connector 230 and a heat exchanger portion 240. A water trap 161 with corresponding drainpipe 160 is arranged under the heat exchanger portion 240 and may comprise a draining piece 162 connected to a draining portion of the heat exchanger portion. The lid 220 may be provided with additional perforations 222. The wastewater from the shower enters the heat exchanger through perforations 222 or the surrounding slit 221. Guiding surface 211 may be arranged to guide the water onto the heat exchanger portion 240. The water flow is indicated with dashed lines in the drawing.

The connector 230 is rotationally arranged around the axis 232 and can rotate at least approximately 90 degrees from a first rest position (as shown in Figs. 2 and 3) to a second rest position in which it is a lifted position. The connector 230 comprises an inlet for cold-water and an outlet for heated water to and from the heat exchanger, respectively. The cold-water is guided into the heat exchanger portion 240 via an inlet pipe 234, which is connected to the cold-water 140 (Fig. 1) from the mixer 300. The heated water exits via an outlet pipe 233 and is returned to the mixer 300 via the pipe 170 (Fig. 1).

In one embodiment, the connector 230 may be fixed to the heat exchange portion 240. To be able to access the interior of the heat exchanger 200 and water trap 161 , the lid 220 may be opened, e.g. by rotating around a fixation axis at one end, or removed and the connector 230 fixed to the heat exchanger portion 240 rotated from the first rest position to the second position, as illustrated in Fig. 4. This allows for easy access to the water trap and various parts of the heat exchanger for cleaning, inspection and/or maintenance. The connecter and the heat exchanger portion may be connected in several additional points.

Fig. 5a illustrates the connector 230 from above. Figs. 5b and 5c illustrate cross-sectional views of the connector 230 along lines A-A and B-B, respectively.

The connector 230 comprises a main body 235, inlet 236, outlet 237, connection pipe 233 to return water, connection pipe 234 to feed cold water, internal channel 2361 for cold water, internal channel 2371 for return water and rotatable joints 238 between connection pipes 236, 237 and the body 235.

The channels 2361 and 2371 are arranged inside the body 235. The body may be made of any suitable material such as plastic, metal, etc. However, the channels must be insulated or made of material with poor thermal conductivity so that the heated water does not lose heat. The channel 2361 connects the cold-water inlet 236 to the cold-water outlet piece 234, which may be fixed (or removably fixed with sealing) to the body of the heat exchanger portion 240. The channel 2371 connects the return water outlet 237 to the return water inlet piece 233, which may be fixed to heat exchanger portion 240 (or removably fixed with a sealing).

The entire body 235 and pieces 233 and 234 are rotatable around the axis 232, which according to this embodiment is perpendicular to the longitudinal axis of the body 235. The rotation is enabled by using rotatable joints 238, which may comprise rotary joints known and available on the market or known. Clearly, the position of connections 236 and 237 may vary depending on the use and installation.

Fig. 6a is a view from above of the heat exchanger portion 240, according to one embodiment of the invention. Fig. 6b is a cross sectional view of the portion of the heat exchanger 240 along lines C-C and a partial enlargement of the heat exchanger portion 240.

The surfaces of the heat exchanger portion 240, function as a water distributer, comprise a distribution portion 241 and channels 242 inside the distribution portion 241 , a connection 243 to the cold-water piece 234, connection 244 to return water piece 233 and a drain opening 246. In one embodiment the connections 243 and/or 244 may comprise quick coupling (e.g. push-pull quick release or threated quick release) or hose coupling, with female body attached to one of the connector 230 or the heat exchanger 240 and the male tip connected to heat exchanger or the connector, respectively. A sealing (washer) or welding may also be used to connect the connector pieces (233, 234) to the heat exchanger portion.

The distribution portion 241 distributes the wastewater over the heat exchanger portion and channels through which flows the fresh water to be heated. The distributer portion may for example be made of pressed sheet of stainless steel, (chrome) plated copper, aluminum or any other suitable material with good thermal conductivity, e.g. formed by joining upper and lower portions such that a channel system 242 for the cold-water shaped as a continuous spiral loop, with a height difference between the beginning and end of the spiral, is formed. The height difference means that the connection 244 is situated substantially higher than the connection 243 with respect to the bottom base of the heat exchanger portion. Thus, the spiral loops are formed as stairs in cross-section. The inclination of the spiral loop results in that the warm wastewater flowing outside the channels 242 alongside the inclined loop wash over the loops from the outer peripheries of the heat exchanger portion towards its midpoint, substantially in a counter-current direction to the cold-water, which is pushed from the midpoint towards the outlet 233 in the channels. The cold-water in the channels flow due to the water pressure of the cold water. The floor drain may have a lower part 180 spaced from the distributer portion 241 with thermal transfer characteristics, which allows for additional wastewater to flow under the conductor portion, providing for further heat exchange.

In yet other embodiments, as illustrated schematically in Figs. 7 and 8, the heat exchanger portion’s 240 distributer portion may comprise pipes 248/248’, slightly tilted in one direction (sloping downwards in the direction of arrow a) so that the wastewater flows in one direction, both above and below the pipes. In this case, the cold-water fed through the piece 243 flows in an opposite direction. The heat exchanger can be made of compressed copper pipes or extruded aluminum, or any other suitable material with good thermal conductivity.

One object of the invention is to provide a heat exchanger that serves for heat recovery and is subjected to low pressure load on the fed water side. Consequently, the cold-water to be heated with recovered heat from the wastewater is connected directly from the household or domestic water with same pressure. Household/domestic water is water used for indoor and outdoor household purposes. For this reason, the mixer 300 is designed to be able to feed the water to the heat exchanger 200 and mix the returned water with elevated temperature and mix it with the hot water.

Fig. 9 is an alternative embodiment of the heat exchanger 200. In this embodiment, the heat exchanger portion 240 comprises an additional back support portion 247 with hinges 249. The rotation axis of the hinges 249 coincides with the rotation axis 230 of the connector 230. This design allows more stable hanging of the heat exchanger portion 240. The distributer 241 may be provided with vias 2401 connecting the upper surface of the distributer to the backside of it through channels 242 to allow wastewater to flow through to backside of the distributer, i.e., the space between lower part 180 and the distributer. The vias 2401 are arranged at the curves (in opposite surface) but may be arranged in a suitable position along the spiral stairs. In one embodiment the heat exchanger portion 240 may be hinged having a rotational axis same as the connector 230.

Fig. 10 illustrates schematically an embodiment of a shower mixer 300 and its interior. The shower mixer comprises a housing 310, a wall fitting portion 311, a temperature control (or tap) 320, a water flow on/off/di verter control (or tap) 330, a hot-water valve 350, a cold-water valve 360, a thermostat 340, and connections to: cold-water 140, warm water 150, water feed pipe to heat exchanger 160, return water from the heat exchanger 170 and to shower head 180.

In use, the water flow control 330 is turned on, which opens the valve 360 and depending on the water temperature, control valve’s position, an amount of cold-water (represented by dotted arrow 312) is fed to the heat exchanger and warm water (represented by dot dashed line 313) is fed to the thermostat 340. Initially, only the hot-water from a hot-water source (such as a boiler) is used. When the heat exchanger recovers and returns heated water (represented by double dot dashed line 314) to the thermostat, the hot-water 313 and heated water 314 are mixed and temperature of the water 315 to the shower is increase. The user decreases the amount of the hot-water from the hot-water source by increasing the temperature by using the temperature control 320 until a desired temperature is obtained. The circulation in the entire system is thus affected and operates due to the pressure of the cold water.

Although the connector 230 is shown substantially centrally positioned in several embodiments, it may be arranged in any position along the long side or short side of the heat exchanger allowing. A combination of the different embodiments and combination of features from different embodiments is also possible.

In different constructions, the floor drain may be designed so that it can be used with or without the heat exchanger and its water connections. This makes it possible to choose to or later remove the heat exchanger without affecting the built-in floor drain. The heat exchanger's connecting pipes can be mounted hidden or visible. The floor drain may be designed for both concealed and visible pipe connections. In the case of a visible pipe connection up to the shower mixer, the lid to the floor drain may have a customized design. It should be noted that the word “comprising” does not exclude the presence of other elements or steps than those listed and the words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements. It should further be noted that any reference signs do not limit the scope of the claims.

The foregoing description of embodiments of the present invention, have been presented for purposes of illustration and description. The foregoing description is not intended to be exhaustive or to limit embodiments of the present invention to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments of the present invention. The embodiments discussed herein were chosen and described in order to explain the principles and the nature of various embodiments of the present invention and its practical application to enable one skilled in the art to utilize the present invention in various embodiments and with various modifications as are suited to the particular use contemplated. The features of the embodiments described herein may be combined in all possible combinations of methods, apparatus, modules, and systems.

Claims

1. A heat exchanger (200) for installation in a drain compartment and comprising a heat exchanger portion (240) and a connector (230) comprising an inlet (236) and an outlet (237), characterized in that the heat exchanger portion (240) and the connector (230) are arranged rotatable around a rotation axis (232) such that the heat exchanger portion and the connector (230) are rotatable from a first position to a second position.

2. The heat exchanger of claim 1, wherein the inlet (236) is configured to be connected to a cold-water feed and the outlet (237) is configured to be connected to an inlet of a water mixer (300).

3. The heat exchanger according to any of preceding claims, wherein the heat exchanger portion (240) is configured such that a cold-water flows in one direction and a wastewater, to affect the cold-water temperature, in an opposite direction.

4. The heat exchanger of claim 3, comprising a channel (242) with a feed point (243) for the cold-water and a return point (244) for heated water.

5. The heat exchange of claim 4, wherein the channel (242) is formed as a continuous spiral loop with a height difference between the feed point (243) and the return point (244), were the return point (244) is higher than the feed point (243).

6. The heat exchange of claim 4, wherein the channel is formed by inclined tubes.

7. The heat exchanger according to any of previous claims, wherein the heat exchanger portion (240) is made of pressed sheet of stainless steel, plated copper, aluminum, compressed copper pipes or extruded aluminum.

8. The heat exchanger according to claim 7, wherein the heat exchanger portion is made by joining upper and lower portions such that a channel system (242) for the cold- water is shaped there between.

9. The heat exchanger according to any of previous claims, wherein the heat exchanger is configured to be connected to a water mixer (300), whereby the inlet (243) is connected to cold-water outlet of the water mixer and the return outlet (244) is connected to a hot-water inlet of the water mixer.

10. A heat exchanger system for heat cold-water by means of heat from wastewater, the system comprising:

• a heat exchanger (200) configured to be arranged in a drain compartment;

• a mixer (300) for providing cold-water from a cold-water source and receive water with altered temperature; the heat exchanger (200) comprising:

• a heat exchanger portion (240) comprising: o a number of channels (242) for circulating the cold-water from the mixer (300); and o an outer surface covering the channels (242) for distributing the wastewater at least on one surrounding surface; characterized in that the heat exchanger further comprises a connector (230) configured to receive the cold-water from the mixer and to connect to the heat exchanger portion (240) and return water with changed temperature to the mixer; that the heat exchange portion is arranged rotatable around a rotational axis (232), allowing the heat exchanger portion (240) to rotate from a first resting position to a second raised position.

11. The heat exchanger system of claim 10, for use in a shower, bathtub or sink.

12. The heat exchanger system of claim 10 or 11 , wherein the heat exchanger portion (240) is configured such that a cold-water to be heated flows in one direction and wastewater substantially in an opposite direction.

13. The heat exchanger system according to any of claims 10 to 12, comprising a channel (242) with a feed connection (243) for the cold-water and a return connection (244) for the heated water are connected to the channel (242), which is formed as a continuous spiral loop with a height difference between the feet point and the return point.

14. The heat exchanger system according to any of claims 10 to 13, wherein the channel is formed by inclined tubes. 14

15. The heat exchanger system according to any of claims 10 to 14, wherein the heat exchanger portion is made of pressed sheet of stainless steel, plated copper, aluminum, compressed copper pipes or extruded aluminum.

16. The heat exchanger system according to claim 15, wherein the heat exchanger portion is made by joining upper and lower portions such that a channel system (242) for the first medium is shaped there between.

17. The heat exchanger system according to claim 13, wherein the feed connection and return connection comprise one or several of quick connection, hose connection, welding, or a seal.

18. The heat exchanger system according to any of claims 10 to 14, the heat exchanger portion comprising through channels (2401) for guiding wastewater from one surface to opposite surface.