U.S. patent application number 13/701539 was filed with the patent office on 2013-06-13 for device for preparing hot water by recovering heat from waste water.
This patent application is currently assigned to BSH Bosch und Siemens Hausgerate GmbH. The applicant listed for this patent is Stefan Holzer, Evgeni Rehfuss, Andreas Renner, Markus Spielmannleitner, Gerhard Wetzl. Invention is credited to Stefan Holzer, Evgeni Rehfuss, Andreas Renner, Markus Spielmannleitner, Gerhard Wetzl.
Application Number | 20130145788 13/701539 |
Document ID | / |
Family ID | 44626620 |
Filed Date | 2013-06-13 |
United States Patent
Application |
20130145788 |
Kind Code |
A1 |
Holzer; Stefan ; et
al. |
June 13, 2013 |
DEVICE FOR PREPARING HOT WATER BY RECOVERING HEAT FROM WASTE
WATER
Abstract
A device for preparing hot water by recovering heat from waste
water includes a heat pump which has a compressor and an
evaporator. The evaporator supplies thermal energy to a hot water
reservoir which is disposed above the compressor. At least one heat
pipe thermally connects the hot water reservoir to the compressor
of the heat pump and is constructed to dissipate waste heat
produced during operation of the compressor to the hot water
reservoir.
Inventors: |
Holzer; Stefan; (Aalen,
DE) ; Rehfuss; Evgeni; (Munchen, DE) ; Renner;
Andreas; (Giengen, DE) ; Spielmannleitner;
Markus; (Ellwangen, DE) ; Wetzl; Gerhard;
(Sontheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Holzer; Stefan
Rehfuss; Evgeni
Renner; Andreas
Spielmannleitner; Markus
Wetzl; Gerhard |
Aalen
Munchen
Giengen
Ellwangen
Sontheim |
|
DE
DE
DE
DE
DE |
|
|
Assignee: |
BSH Bosch und Siemens Hausgerate
GmbH
Munich
DE
|
Family ID: |
44626620 |
Appl. No.: |
13/701539 |
Filed: |
May 26, 2011 |
PCT Filed: |
May 26, 2011 |
PCT NO: |
PCT/EP2011/058614 |
371 Date: |
January 30, 2013 |
Current U.S.
Class: |
62/238.7 ;
165/104.26; 62/513 |
Current CPC
Class: |
Y02B 30/18 20130101;
F28D 15/043 20130101; F24D 2220/07 20130101; Y02B 30/52 20130101;
F24D 17/02 20130101; F24D 17/001 20130101; F24H 4/04 20130101 |
Class at
Publication: |
62/238.7 ;
165/104.26; 62/513 |
International
Class: |
F24H 4/04 20060101
F24H004/04; F28D 15/04 20060101 F28D015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 9, 2010 |
DE |
10 2010 029 880.8 |
Claims
1-10. (canceled)
11. A device for preparing hot water by recovering heat from waste
water, said device comprising: a heat pump comprising a compressor
and an evaporator; a hot water reservoir supplied with thermal
energy by the evaporator of the heat pump above the compressor; and
a heat pipe thermally connecting the hot water reservoir to the
compressor of the heat pump to dissipate waste heat produced during
operation of the compressor to the hot water reservoir.
12. The device of claim 11, wherein the heat pump is constructed
for household application.
13. The device of claim 11, wherein the heat pipe is permanently
connected with thermal contact to one of the hot water reservoir
and compressor by bonding, welding or soldering.
14. The device of claim 11, further comprising a clamping piece
fixed to a member selected from the group consisting of the hot
water reservoir or compressor, said heat pipe being detachably
connected with thermal contact to the member via the clamping
piece.
15. The device of claim 11, wherein the heat pipe comprises a tube
having an elastic region.
16. The device of claim 11, wherein each of the compressor, the
heat pipe and the hot water reservoir comprise thermal
insulation.
17. The device of claim 11, further comprising a shared insulation
enclosing the compressor, the heat pipe, and the hot water
reservoir.
18. The device of claim 16, wherein the insulation comprises a
coating that reflects infrared radiation.
19. The device of claim 18, wherein the coating comprises
aluminum.
20. The device of claim 17, wherein the shared insulation comprises
a coating that reflects infrared radiation.
21. The device of claim 20, wherein the coating comprises
aluminum.
22. The device of claim 11, wherein the compressor comprises a
metallic gloss, low-radiation surface.
23. The device of claim 22, wherein the surface comprises a
corrosion-resistant material.
24. The device of claim 22, wherein the corrosion-resistant
material comprises aluminum or chrome.
Description
[0001] The invention relates to a device for preparing hot water by
recovering heat from waste water by means of a heat pump comprising
a compressor and an evaporator, in particular by means of a small
heat pump for household applications, having a hot water reservoir,
which is supplied with thermal energy by the evaporator of the heat
pump.
[0002] Heat is generally recovered from waste water in devices
known from practical use by means of a saturated steam circulation
process. The compressor used here heats up during operation
generally to temperatures in a range between around 70.degree. C.
and 90.degree. C., which are therefore generally much higher than
the temperature of the hot water reservoir which is maximum around
60 degrees. This higher temperature means that the compressor emits
appreciable heat to the environment, easily amounting to more than
50 watts. This compressor heat is therefore lost so the small heat
pump does not achieve a sufficiently high level of efficiency for
economical operation.
[0003] A solution is already known from EP 0 114 583 A2, in which
the compressor is connected directly to the hot water container.
This means that during operation of the compressor heat from the
compressor is emitted to the hot water reservoir but during the
generally quite long idle time of the compressor heat flows in the
reverse direction from the hot water container into the now colder
compressor, with the result that useful heat is lost to a
significant degree. To prevent this, in a device according to U.S.
Pat. No. 4,448,347 the compressor is even present within the hot
water reservoir, which allows better waste heat utilization but
means that the structure is much more complex and therefore more
expensive. It also makes the surface of the hot water reservoir
larger, thereby increasing the loss of heat to the environment.
[0004] Based on this the object of the invention is to utilize the
waste heat from the compressor in a simple and economical manner,
in order in this way to achieve a more efficient mode of operation
during the recovery of heat from waste water.
[0005] According to the invention this object is achieved in that
the hot water reservoir is thermally connected to the compressor of
the heat pump by way of at least one heat pipe, the hot water
reservoir being disposed above the compressor and the at least one
heat pipe serving to dissipate waste heat produced during operation
of the compressor to the hot water reservoir.
[0006] The resulting advantages essentially consist in that, in
addition to the quantity of heat transmitted by means of the
evaporator, the waste heat produced at the compressor of the heat
pump during its operation can also be transmitted, it being
possible, as known, for said heat pipes or heat tubes to transport
large quantities of heat when arranged and embodied in an
appropriate manner, in so far as the heat source, in this instance
the compressor, is located at the lower end of the heat pipe and
the heat sink, in this instance the hot water reservoir, is located
at the higher end. Such heat pipes are generally filled with a
readily evaporated fluid, which collects in the region of the lower
end. When this region is heated, the fluid evaporates and the vapor
is distributed throughout the pipe, the vapor condensing in the
colder upper region and the condensate running back down due to the
gradient. Large heat flows are transported by evaporation and
condensation, without requiring an external drive system.
[0007] However when the upper end is heated, heat can only be
transported due to heat conduction in the thin pipe wall. As the
fluid is at the bottom, evaporation does not take place and
therefore neither does condensation. The heat flow is therefore
much smaller from the upper to the lower end so that when the
compressor is deactivated, the heat remains in the hot water
reservoir.
[0008] In order to achieve the maximum possible efficiency, the
invention further proposes that the heat pipe should be connected
with good thermal contact to the hot water reservoir or compressor
by bonding, welding or soldering by means of a connection that
cannot be released on one or both sides.
[0009] It is however also possible within the context of the
invention for the heat pipe to be connected with good thermal
contact by means of a connection that can be released on one or
both sides by way of clamping pieces or comparable connecting means
connected in a fixed manner to the hot water reservoir or
compressor. This solution allows more flexible construction options
for the device. In particular it is easier to take apart for
maintenance purposes.
[0010] It is also of advantage if the heat pipes consist of at
least partly elastically configured tubes. Firstly this allows a
large free selection of positions for the hot water reservoir and
compressor, the only condition being that the compressor is
disposed lower than the hot water reservoir. The elastic
configuration of the tubes of the heat pipes means that the
compressor vibrations occurring during operation can be absorbed
more readily so they are not transmitted to the reservoir. This
generally allows the device to operate more quietly.
[0011] In order also to avoid heat losses to the environment, it is
recommended that the compressor, the heat pipes and the hot water
reservoir are enclosed by a shared insulation.
[0012] It is particularly advantageous here for the insulation to
be provided with a coating that reflects infrared radiation, so
that no radiant heat can be lost through the insulation.
[0013] Aluminum is particularly suitable for the coating
material.
[0014] In order also to keep the emission of heat produced in the
compressor low, it is further recommended that the compressor has a
metallic gloss, low-radiation surface. This surface is expediently
made of corrosion-resistant material such as aluminum or
chrome.
[0015] The invention is described in more detail below based on an
exemplary embodiment illustrated in the drawing. The single FIGURE
shows a schematic illustration of a device according to the
invention.
[0016] The device shown only schematically in the drawing serves to
prepare hot water, with heat being recovered from the waste water
that results preferably with household applications by means of a
heat pump. This heat pump consists in the usual manner of a
compressor 1 and an evaporator (not shown in detail) as well as of
a condenser and throttle valve (also not shown in the drawing).
Such devices configured in the form of a small heat pump can be
used in particular for household applications.
[0017] Provision is also made for a hot water reservoir 2, which is
supplied with thermal energy by the evaporator of the heat pump.
The hot water reservoir 2 is set up with connectors 3 (only
outlined in the drawing) for water on the one hand and the cooling
circuit on the other hand, the connectors 3 not being shown in
detail in the drawing for the sake of clarity.
[0018] The hot water reservoir 2 is thermally connected to the
compressor 1 of the heat pump by way of two so-called heat pipes 4,
the arrangement being selected so that the hot water reservoir 2 is
disposed above the compressor 1. These heat pipes 4 or heat tubes
are filled with a readily evaporated fluid, which collects in the
lower region. When this lower region is heated, in this instance by
the compressor 1, the fluid evaporates and the vapor is distributed
throughout the pipe, said vapor condensing back in the colder upper
region and emitting the condensation heat there.
[0019] This type of heat transmission ensures that heat is
transported essentially from bottom to top, as there is no fluid
that could evaporate in the upper region. Heat is therefore only
transported from top to bottom by way of heat conduction through
the heat tube. However this component is comparatively very small.
This means that the compressor 1, which is generally at a higher
temperature than the hot water reservoir 2 during operation, emits
heat to the hot water reservoir 2. If the compressor 1 is
deactivated however, the essentially unidirectional heat
transmission through the heat pipes 4 prevents heat flowing from
the hot water container to the then cooler compressor 1.
[0020] To achieve optimum heat transmission, the two heat pipes 4
are in good thermal contact with the hot water reservoir 2 or
compressor 1, this thermal contact consisting of either a
non-releasable connection by bonding, welding or soldering or a
releasable connection, with clamping pieces 5 or comparable
connecting means connected in a fixed manner to the hot water
reservoir 2 or compressor 1 then being provided, which accommodate
the ends of the heat pipes 4.
[0021] The heat pipes 4 can consist, in a manner not shown in
detail in the drawing, of at least partly elastically configured
tubes, these allowing simpler assembly and a largely free selection
of the position of the hot water reservoir 2 in relation to the
compressor 1. The elastic tubes can also absorb the vibrations of
the compressor 1 occurring during operation, so they are not
transmitted to the reservoir, thereby allowing quieter operation
generally.
[0022] To prevent heat loss, the compressor 1, the heat pipes 4 and
the hot water reservoir 2 are generally provided with insulation in
a manner that is also not illustrated in detail, it being possible
for said insulation to be configured so that the compressor 1, the
heat pipes 4 and the hot water reservoir 2 are all enclosed by it.
In order also to shield the radiant heat within the insulation,
said insulation can be provided with a coating that reflects
infrared radiation. Aluminum is particularly suitable for this
coating. In order also to keep any emission of infrared radiation
from the compressor 1 as low as possible, it should not be painted
black in the usual manner but should have a metallic gloss,
low-radiation surface. A corrosion-resistant material such as
aluminum or chrome is particularly recommended for this.
* * * * *