[0001] The present invention relates to a device for recovering heat from shower water.
The invention further relates to a method for recovering heat from shower water.
[0002] Devices wherein heat is recovered from shower water are known in practice. One of
the known devices comprises a heat exchanger which is connected to the drain of a
shower. In the heat exchanger the heat of the shower water is relinquished to supplied
water. The heat exchanger is usually situated under the drain, making the device particularly
suitable for apartments. The supplied water can then be carried to the mixer tap of
the shower while already preheated by the shower water.
[0003] An alternative device comprises a pump which is arranged in the drain of the shower.
The pump is configured to pump the shower water upward so that the shower water can
be carried into a heat exchanger. This enables the shower and the heat exchanger to
be placed on the same floor, and enables (for instance) installation of the device
in high-rise construction.
[0004] A drawback of the heat recovery device provided with a pump is that the pump capacity
of the pump is usually at least two times, normally three times, greater than the
flow rate of the shower. This in order to prevent the drain of the shower from overflowing.
The drawback thereof is that the heat exchanger is only being fed water one third
of the time. This has the result that the heat recovery device recovers heat less
efficiently.
[0005] The present invention has for its object to obviate or at least reduce the above
stated problems. It can be a particular object of the invention to provide a heat
recovery device which recovers heat from the shower water more efficiently.
[0006] This object is achieved with a heat recovery device for recovering heat from shower
water, wherein the heat recovery device comprises:
- a pump which is configured to pump shower water from a drain of a shower;
- a heat exchanger which is operatively connected to the pump for the purpose of recovering
heat from the shower water supplied by the pump; and
- a buffer vessel arranged between the pump and heat exchanger for the purpose of supplying
the shower water to the heat exchanger in controlled manner, wherein the buffer vessel
comprises:
∘ a first wall and a side wall, wherein the first wall extends substantially in a
first plane, wherein the first wall and side wall define a buffer space which is configured
to store shower water;
∘ an infeed opening for receiving shower water in the buffer space, wherein the infeed
opening is operatively connected to the pump;
∘ an outfeed opening provided in the first wall for the purpose of discharging shower
water to the heat exchanger substantially in a first direction,
∘ a restriction element arranged in front of the outfeed opening for the purpose of
restrictively allowing the shower water to pass from the buffer space to the outfeed
opening.
[0007] Owing to the restriction element which is arranged in front of the outfeed opening,
the shower water which is supplied through the infeed opening is allowed to pass to
the outfeed opening restrictively. The shower water is hereby supplied to the heat
exchanger gradually. An advantage hereof is that a greater proportion of the heat
stored in the shower water can be relinquished by the heat exchanger to supplied shower
water, this increasing the efficiency of the device. This will ultimately result in
a decrease in energy costs for the user of the shower, since the necessary temperature
increase of the supplied water for a determined shower temperature is reduced.
[0008] Because the pumped-up shower water is temporarily stored in the buffer vessel and
is fed to the heat exchanger gradually, the flow rate flowing through the outfeed
opening is levelled. A peak generation of heat by the heat exchanger is levelled hereby.
This increases the efficiency of the device still further.
[0009] A further advantage of the device is that the device according to the invention can
be used in combination with a simple pump. This reduces the costs of the device as
a whole.
[0010] No complicated control system is further required to pump up the correct quantity
of shower water for an optimal absorption of heat by the heat exchanger. This reduces
the chances of malfunctioning of the device.
[0011] The first direction is preferably substantially perpendicular to the first plane.
The first direction is preferably substantially parallel to the direction of the force
of gravity of the earth.
[0012] In use, the first wall is preferably a lower wall. The side wall preferably extends
in the first direction. The side wall preferably extends substantially perpendicularly
of the first plane.
[0013] In the present patent application the term operatively connected is understood to
mean a liquid connection. The liquid connection can for instance comprise a conduit
or tube. The term drain of a shower is understood to mean an element configured to
catch the shower water.
[0014] The outfeed opening is operatively connected to the heat exchanger. The outfeed opening
preferably debouches in the heat exchanger.
[0015] The restriction element can be both a fixed element which restrictively allows the
liquid flow to pass or an element which actively controls the liquid flow.
[0016] In an embodiment according to the invention the restriction element comprises an
outfeed chamber which is provided over the outfeed opening and which separates the
buffer space and the outfeed opening at least partially, wherein a chamber opening
which restrictively allows the shower water to pass from the buffer space to the outfeed
opening is arranged in the outfeed chamber.
[0017] The chamber opening preferably has a throughfeed surface which is smaller than the
outfeed opening. An effective restriction element is obtained with the outfeed chamber
and the chamber opening.
[0018] In an embodiment according to the invention the chamber opening is configured to
feed shower water from the buffer space through to the outfeed opening onto a distributing
wall which is configured to distribute the shower water uniformly over the outfeed
opening.
[0019] The distributing wall preferably extends substantially in the first plane. The distributing
wall preferably extends in the first plane over a predetermined length. The distributing
wall can form (an integral) part of the first wall. The distributing wall is preferably
positioned (all) around the outfeed opening.
[0020] An advantage of the distributing wall is that the shower water is distributed uniformly
in the outfeed opening. This realizes a greater active exchanging surface of the shower
water in the heat exchanger, resulting in a more efficient heat transfer.
[0021] In an embodiment according to the invention the outfeed opening is circular and the
outfeed chamber comprises a side distributing wall which extends in a first direction
and which is arranged around the outfeed opening in a spiral shape.
[0022] In this embodiment the chamber opening is arranged such that the shower water carried
through the chamber opening flows onto or along the side distributing wall. The side
distributing wall is preferably arranged substantially perpendicularly of the distributing
wall. The side distributing wall preferably extends substantially in the first direction.
[0023] An advantage of the side distributing wall is that the shower water is guided along
the spiral-shaped side distributing wall. The shower water is hereby distributed over
the entire area lying around the outfeed opening. The shower water is preferably distributed
over the distributing wall. Distributing the shower water realizes a more efficient
heat transfer in the heat exchanger.
[0024] In an embodiment according to the invention the device further comprises an obstruction
element arranged in front of the infeed opening, wherein the obstruction element is
positioned at a predetermined distance from the infeed opening.
[0025] The obstruction element is an element which reduces the speed of the throughfeed
of the shower water. The obstruction element can be positioned both in front of, in
and behind the infeed opening. The obstruction element can comprise a physical element
or a bend, curve or corner. The obstruction element preferably takes the form of a
physical element which is placed downstream of the infeed opening, as seen in the
flow direction of the shower water, and which is configured to interrupt the flow
of supplied shower water.
[0026] An advantage of the obstruction element is that the speed of the shower water in
the buffer vessel is reduced by placing the obstruction element in front of the water
jet. The shower water supplied by the pump is hereby carried against a wall of the
container at a lower speed, which has the advantage that less noise nuisance is realized
by the supplied shower water. Alternatively or additionally, it is prevented that
shower water can be sprayed directly into an overflow protection, if present.
[0027] In an embodiment according to the invention the infeed opening is provided in the
first wall.
[0028] By providing the infeed opening in the first wall an infeed tube which connects the
pump to the buffer vessel can be connected in simple manner.
[0029] In an embodiment according to the invention the device further comprises an overflow
element connected operatively to the outfeed opening, wherein the overflow element
comprises an overflow opening which is positioned at a predetermined distance from
the outfeed opening, as seen in a direction.
[0030] When too much shower water is present in the buffer vessel, the excess shower water
can be discharged directly to the heat exchanger by the overflow element. This prevents
the buffer vessel or the drain of the shower from overflowing.
[0031] In an embodiment according to the invention the overflow opening is connected to
the outfeed chamber.
[0032] An advantage of being connected to the outfeed chamber is that a liquid connection
between the overflow opening and the outfeed opening is realized in simple manner.
The excess shower water is hereby discharged to the heat exchanger in effective manner.
[0033] In an embodiment according to the invention the overflow element comprises a housing
which extends substantially in the first direction between a lower and an upper end,
wherein the outfeed opening is positioned at a lower end and the overflow opening
is positioned at an upper end.
[0034] The overflow element is preferably cylindrical here, with the overflow opening at
an upper end and the outfeed opening close to a lower end. The lower end preferably
debouches in the outfeed chamber. The housing of the overflow element is preferably
hollow, such that a liquid connection between the overflow opening and the lower end
is realized.
[0035] An advantage of the above stated embodiment is that, when the shower water is in
the buffer space above a determined height, it can be carried freely from the buffer
space to the outfeed opening owing to the overflow element. This prevents overflowing
in the buffer vessel and/or in the drain of the shower. Alternatively or additionally,
an advantage of the overflow element is that the buffer vessel can be vented when
the buffer space is filled with shower water by the pump.
[0036] In an embodiment according to the invention a second restriction element is provided
in front of the chamber opening.
[0037] The second restriction element prevents dirt from finding its way into the outfeed
opening or outfeed chamber. This prevents the heat exchanger from becoming clogged.
[0038] In an embodiment according to the invention a mesh-like element is arranged in front
of a pump opening.
[0039] Mesh-like element is understood to mean an element having a mesh-like structure.
The mesh-like element prevents dirt from finding its way into the pump. Shower water
is hereby as it were purified before it is pumped up to the buffer vessel. An advantage
hereof is that clogging of the pump, the buffer vessel and/or the heat exchanger is
prevented.
[0040] In an embodiment according to the invention a closable opening is provided in the
side wall of the buffer vessel, wherein the closable opening is positioned at a location
such that the chamber opening is reachable from the closable opening with an elongate
element, for instance a stick.
[0041] Owing to the closable opening an elongate element, for instance a stick, needle or
other elongate element with a diameter smaller than the closable opening, can be inserted
into the buffer space in simple manner. Because the chamber opening is reachable from
the closable opening, a blockage in the chamber opening can be removed in simple manner
by means of the elongate element.
[0042] In an embodiment according to the invention the pump comprises a level sensor.
[0043] The use of the level sensor allows the pump to be switched on in simple manner the
moment that the level sensor exceeds a predetermined threshold value. This effectively
prevents the drain of the shower from overflowing.
[0044] In an embodiment according to the invention the level sensor comprises a float switch.
[0045] An advantage of a float switch is that it provides a relatively inexpensive level
sensor.
[0046] In an embodiment according to the invention the heat exchanger comprises a tube-in-tube
heat exchanger.
[0047] The tube-in-tube heat exchanger comprises an outer cylindrical periphery through
which the shower water is carried in the first direction, and comprises a cylindrical
throughfeed provided in the periphery for throughfeed of new shower water, wherein
the shower water relinquishes its heat to the new shower water in the heat exchanger.
[0048] An efficient heat exchanger is hereby provided.
[0049] In an embodiment according to the invention the heat exchanger comprises a falling
film heat exchanger.
[0050] The falling film heat exchanger provides an even more efficient heat exchanger by
increasing the surface of the shower water along the supplied water.
[0051] In an embodiment according to the invention an O-ring is provided round the outfeed
opening on an underside of the first wall for the purpose of connection to the heat
exchanger.
[0052] The O-ring realizes a liquid-tight connection between the heat exchanger and the
buffer vessel.
[0053] The invention further relates to a shower provided with a heat recovery device according
to any one of the foregoing embodiments.
[0054] The shower has similar advantages and effects as described for the device.
[0055] The invention further relates to a method for recovering heat from shower water,
comprising of:
- providing a heat recovery device according to the invention or a shower according
to the invention;
- pumping the shower water to the buffer vessel;
- restrictively allowing the shower water to pass to the heat exchanger; and
- exchanging heat of the shower water with supplied shower water in the heat exchanger.
[0056] The method has similar advantages and effects as described for the device and the
shower.
[0057] Further features, advantages and details of the invention are described on the basis
of embodiments thereof, wherein reference is made to the accompanying drawings, in
which:
- figure 1 is a schematic representation of a device according to the invention;
- figure 2 is a cross-section of a buffer vessel according to the invention;
- figure 3A is a perspective view of the inside of the buffer vessel; and
- figure 3B is a top view of the inside of the buffer vessel.
[0058] Device 2 (figure 1) comprises pump 4, buffer vessel 6 and heat exchanger 8. Pump
4 is arranged in drain 10, wherein drain 10 is positioned beneath surface 12 of shower
14. Pump 4 is connected to float switch 16. Float switch 16 measures the liquid level
in drain 10. If float switch 16 measures that the liquid level in drain 10 exceeds
a determined threshold value, pump 4 is driven to pump up the shower water 11.
[0059] Pump 4 pumps shower water 11 through pipe 18 to buffer vessel 6. Buffer vessel 6
is arranged at a height D
1 relative to surface 12 of shower 14. Shower water 11 is fed through to heat exchanger
8 gradually. In the shown embodiment heat exchanger 8 is a falling film heat exchanger.
Heat exchanger 8 comprises an outer periphery 20 through which shower water 11 is
fed as a thin layer. Arranged inside periphery 20 is inner throughfeed 22 through
which supplied mains water is fed. Because supplied mains water and shower water 11
are carried closely alongside each other, shower water 11 relinquishes its heat to
a supplied mains water. The supplied mains water is then fed with tube 24 to mixer
tap 23. The shower water 11 is discharged to the sewer via sewer pipe 21. Further
connected to mixer tap 23 is hot water tube 25 which supplies heated water. In mixer
tap 23 the water from tube 24 and hot water tube 25 are mixed and fed through to shower
head 26.
[0060] Buffer vessel 6 (figure 2) comprises a first wall 28 which extends substantially
in first plane 30. First plane 30 is defined by directions X and Y. Direction Z is
oriented perpendicularly of first plane 30. Buffer vessel 6 further comprises a second
wall 32 which extends substantially in first plane 30. First wall 28 and second wall
32 are mutually connected by side wall 34, which extends substantially in the direction
Z. First wall 28, second wall 32 and side walls 34 define a buffer space 36 in which
shower water 11 can be stored.
[0061] Provided in first wall 28 is infeed opening 38 through which shower water 11 can
be supplied by means of pump 4. Obstruction element 41 is arranged in front of infeed
opening 38. Obstruction element 41 is positioned in front of the flow direction of
shower water 11 such that the speed of incoming shower water 11 is reduced. Further
arranged in first wall 28 is outfeed opening 40 for outfeed of shower water 11 from
buffer vessel 6 to heat exchanger 8.
[0062] Positioned all around outfeed opening 40 is outfeed chamber 42. Outfeed chamber 42
separates chamber space 44 from buffer space 36. Chamber space 44 and buffer space
36 are connected to each other by chamber opening 46. Shower water 11 can be fed through
to heat exchanger 8 through chamber opening 46. Because chamber opening 46 has a smaller
area than infeed opening 38 and outfeed opening 40, chamber opening 46 functions as
restriction element for restrictively allowing shower water 11 to pass to heat exchanger
8.
[0063] Further arranged on outfeed chamber 42 is overflow 48. In the shown embodiment overflow
48 is a cylindrical and hollow element extending substantially in direction Z between
upper end 50 and lower end 52. Lower end 52 is positioned close to outfeed opening
40. When it reaches level Hi, shower water 11 can be fed directly to outfeed opening
40, and therefore to heat exchanger 8, by overflow element 48.
[0064] Buffer vessel 6 (figures 3A-B) comprises first wall 28 and side wall 34. Obstruction
element 41 is positioned in front of flow direction S of shower water 11 running through
infeed opening 38. Obstruction element 41 comprises two side walls 43a, 43b extending
substantially in direction Z and cover 45 arranged therebetween. Cover 45 has substantially
the same area as infeed opening 38 and is arranged at a distance D2 therefrom.
[0065] Outfeed opening 40 is arranged in first wall 28. Spiral-shaped side wall 54 is placed
round outfeed opening 40. Spiral-shaped side wall 54 extends substantially in first
direction Z. Spiral-shaped side wall 54 at least partially forms outfeed chamber 42.
Initial part 56 of spiral-shaped side wall 54 is arranged further from outfeed opening
40 than end part 58. Spiral-shaped side wall 54 is formed such that end part 58 is
positioned on the same radius from outfeed opening 40, with the difference that end
part 58 is positioned closer to outfeed opening 40. Initial part 56 and end part 58
of spiral-shaped side wall 54 can hereby together form chamber opening 46 of outfeed
chamber 42 at least partially. Spiral-shaped side wall 54 forms a side distributing
wall. Distributing wall 60 is also positioned in spiral shape around outfeed opening
40, such that shower water 11 coming through chamber opening 46 is distributed uniformly
over outfeed opening 40 in combination with spiral-shaped side wall 56.
[0066] The present invention is by no means limited to the above described embodiments thereof.
The rights sought are defined by the following claims, within the scope of which many
modifications can be envisaged.
1. Heat recovery device for recovering heat from shower water, comprising:
- a pump which is configured to pump shower water from a drain of a shower;
- a heat exchanger which is operatively connected to the pump for the purpose of recovering
heat from the shower water supplied by the pump; and
- a buffer vessel arranged between the pump and heat exchanger for the purpose of
supplying the shower water to the heat exchanger in controlled manner, wherein the
buffer vessel comprises:
∘ a first wall and a side wall, wherein the first wall extends in a first plane,
wherein the first wall and side wall define a buffer space which is configured to
store shower water;
∘ an infeed opening for receiving shower water in the buffer space, wherein the infeed
opening is operatively connected to the pump;
∘ an outfeed opening provided in the first wall for the purpose of discharging shower
water to the heat exchanger in a first direction,
∘ a restriction element arranged in front of the outfeed opening for the purpose of
restrictively allowing the shower water to pass from the buffer space to the outfeed
opening.
2. Device according to claim 1, wherein the restriction element comprises an outfeed
chamber which is provided over the outfeed opening and which separates the buffer
space and the outfeed opening at least partially, wherein a chamber opening which
restrictively allows the shower water to pass from the buffer space to the outfeed
opening is arranged in the outfeed chamber.
3. Device according to claim 2, wherein the chamber opening is configured to feed shower
water from the buffer space through to the outfeed opening onto a distributing wall
which is configured to distribute the shower water uniformly over the outfeed opening.
4. Device according to claim 3, wherein the outfeed opening is circular, and wherein
the outfeed chamber comprises a side distributing wall which extends in a first direction
and which is arranged around the outfeed opening in a spiral shape.
5. Device according to any one of the foregoing claims, further comprising an obstruction
element arranged in front of the infeed opening, wherein the obstruction element is
positioned at a predetermined distance from the infeed opening.
6. Device according to any one of the foregoing claims, wherein the infeed opening is
provided in the first wall.
7. Device according to any one of the foregoing claims, further comprising an overflow
element connected operatively to the outfeed opening, wherein the overflow element
comprises an overflow opening which is positioned at a predetermined distance from
the outfeed opening, as seen in a direction.
8. System according to claim 7, when dependent on at least claim 2, wherein the overflow
opening is connected to the outfeed chamber.
9. Device according to claim 7 or 8, wherein the overflow element comprises a housing
which extends substantially in the first direction between a lower and an upper end,
wherein the outfeed opening is positioned at a lower end and the overflow opening
is positioned at an upper end.
10. Device according to any one of the foregoing claims, wherein a second restriction
element is provided in front of the chamber opening.
11. Device according to any one of the foregoing claims, wherein a mesh-like element is
arranged in front of a pump opening, and/or wherein a closable opening is provided
in the side wall of the buffer vessel, wherein the closable opening is positioned
at a location such that the chamber opening is reachable from the closable opening
with an elongate element, for instance a stick, and/or wherein the pump comprises
a level sensor, wherein the level sensor preferably comprises a float switch.
12. Device according to any one of the foregoing claims, wherein the heat exchanger comprises
a tube-in-tube heat exchanger, and/or wherein the heat exchanger comprises a falling
film heat exchanger.
13. Device according to any one of the foregoing claims, wherein an O-ring is provided
round the outfeed opening on an underside of the first wall for the purpose of connection
to the heat exchanger.
14. Shower provided with a device according to any one of the foregoing claims.
15. Method for recovering heat from shower water, comprising of
- providing a device according to any one of the claims 1-13 or a shower according
to claim 14,
- pumping the shower water to the buffer vessel;
- restrictively allowing the shower water to pass to the heat exchanger; and
- exchanging heat of the shower water with supplied shower water in the heat exchanger.