CA1040945A - Waste water heat recovery unit - Google Patents

Waste water heat recovery unit

Info

Publication number
CA1040945A
CA1040945A CA247,783A CA247783A CA1040945A CA 1040945 A CA1040945 A CA 1040945A CA 247783 A CA247783 A CA 247783A CA 1040945 A CA1040945 A CA 1040945A
Authority
CA
Canada
Prior art keywords
tank
waste water
valve
temperature
water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
CA247,783A
Other languages
French (fr)
Other versions
CA247783S (en
Inventor
E. Barry Kinsella
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to CA247,783A priority Critical patent/CA1040945A/en
Application granted granted Critical
Publication of CA1040945A publication Critical patent/CA1040945A/en
Expired legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
    • F24D17/00—Domestic hot-water supply systems
    • F24D17/0005—Domestic hot-water supply systems using recuperation of waste heat
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F28—HEAT EXCHANGE IN GENERAL
    • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
    • F28D21/00—Heat-exchange apparatus not covered by any of the groups F28D1/00 - F28D20/00
    • F28D21/0001—Recuperative heat exchangers
    • F28D21/0012—Recuperative heat exchangers the heat being recuperated from waste water or from condensates
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/18—Domestic hot-water supply systems using recuperated or waste heat
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/56—Heat recovery units

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Heat-Pump Type And Storage Water Heaters (AREA)

Abstract

Abstract The present invention provides a waste water heat recovery unit particularly suitable for domestic uses. The unit comprises a holding tank with a waste water inlet in the top and a waste water drain in the bottom.
A fresh water coil is positioned in the tank, in heat exchange relation-ship with hot waste water retained in the tank. A valve is provided for opening and closing the waste water drain. The valve is thermostatically controlled so as to be closed when a temperature in the tank is greater than a pre-determined temperature, normally 80°F and open when the temperature tank is below the pre-determined temperature. The unit is normally insulated.

Description

109(394S

The present invention is concerned with the recovery of heat from waste water and more particularly from domestic waste water.
Because of the nature of domestic water use, it is not possible to use a scaled down version of a conventional industrial heat exchanger for the recovery of heat from domestic waste water. Such heat exchangers usually require simultaneous flows of both heating and heated fluid, a condition that cannot be met in domestic situations. Industrial heat recovery systems are also quite complex and therefore expensive.
According to the present invention there is provided a waste water heat recovery unit comprising: a holding tank having a waste water inlet and a waste water drain; a fresh water duct providing a fresh water pasaage through the holding tank, in heat exchange relationship with waste water retained therein; a valve for opening and closing said waste water drain; and thermostatic control means for closing said valve in response to a temper-ture in the tank greater than a predetermined temperature and for opening said valve in response to a temperature in the holding tank less than said predetermined temperature.
In most embodiments of the apparatus the tank will be insulated.
The unit is connected in the household waste and fresh water systems with the waste water inlet and outlet respectively receiving waste water from and discharging waste water to the household drains. The fresh water passage receives cold fresh water from the household fresh water ~up~ly, and supplies fresh water to the household hot water tank.
For normal operation, the actuating temperature for the thermostatic control means will be about 80F, somewhat above the normal ambient and hot ~
enough to avoid solidification of most fats and greases in the waste water. ; -In operation, the valve will normally be open and the tank empty. When a charge of hot waste water enters the tank from the household drains, the ~-- -ini~ial part of the charge will flush through the outlet, clearing it of any accumulated sludge, the temperature in the tank will rise and the drain valve will close to retain the major part of the hot waste water charge in the tank.

L ^ ~

,,., . . ., -..... , ........ ., .... ~. . ... . .. . . . .
.. . . . ..

104(~945 Heat will then be transferred from the hot waste water in the tank to the cold fresh water in the fresh water passage through the tank. Normally, this situation will not change until hot water is drawn from the hot water tank of the house, in turn drawing hot fresh water from the fresh water passage through the holding tank into the household hot water tank. This will in turn draw new cold fresh water into the fresh water passage to be heated by the hot waste water in the holding tank. When the waste water has been cooled to the actuation temperature of the thermostatic control, the valve is opened to allow the cooled waste water to discharge from the holding tank.
The present unit is particularly useful in those households where hot water is used in sequential batches, for example, where an automatic dishwasher or a clothes washer is in use.
In the accompanying drawings which illustrate an exemplary embodi-ment of the present invention: ;
Pigure 1 is a perspective view of a heat recovery unit; and Figure 2 is a sectional elevation of the tank of Figure 1 withadded insula~ion.
Referring to the accompanying drawings, there is illustrated a waste water heat recovery unit 10 consisting primarily of a cylindrical holding tank 12. A waste water drain pipe 14 leads from the bottom of the tank. An over-flow pipe 16 also extends through the bottom of the tank 12 and connects to the drain pipe 14. The top end of the overflow is open and spaced well above -the bottom of the tank 12.
The holding tank has a tight fitting cylindrical cover 18 with a central waste water inlet pipe 20 and a vent 22.
Inside holding tank 12 is a cylindrical coil 24 of copper tubing -. ..... ... ... , - .
concentric with the tank, spaced from its side wall and supported above the bottom of the tank by a series of supports 26. Both ends of the tubing are extended upwardly through the cover 18 to provide an inlet 28 leading to -the bottom of the coil a~d an outlet 30 from the top of the coil.
- 2 -. , ~ . : , , . , . ,: . . , . .. ", ,,. :

104~945 A circular cover 32 is positioned over the coil 24 and carries a depending tube 34 positioned concentrically around the overflow pipe 16.
The bottom of tube 34 is spaced above the bottom of tank 12 and the top of overflow pipe 16 is spaced below cover 32.
Waste water drain 14 is provided with a slide valve 36 consisting of a plate 38 lying flat on the bottom of tank 12 and fixed to a vertical rod 40 so as to swing about the axis of the rod to close and open the mouth of the drain pipe 14.
Rod 40 extends upwardly through the cover 18 of tank 12 and is rotated by a valve actuating mechanism 42. This mechanism includes an over-center mechanism consisting of a lever arm 44 secured to the upper end of and projecting radially from the rod 40, a bracket 46 mounted on the cover on a side of rod 40 away from lever arm 44 and a coil spring 48 with one ent connected to bracket 46 and the other end connected to lever arm 44.
The end of spring 48 connected to lever arm 44 is arranged so as to be able to pass over the lever arm as it swings from one over-center position to the other.
In order to swing arm 44, the valve actuator mechansim includes two opposed solenoids 50 and 52 with their armatures pin jointed to lever arm 44 at 54. A pair of normally closed microswitches 56 and 58 are mounted on -opposite sides of arm 44 for engagement by the arm when in its respective over-center positions. Electrically, microswitches 56 and 58 are connected in series with solenoids 50 and 52 respectively by suitable wires 60. ~-A thermostatic switch 62, of the type having two sets of contacts, is unted in the side wall of the tank 12 so as to operate in response to internal tank temperature. The contacts of switch 62 are arranged in series with res- - -pective ones of the solenoids S0 and 52 and the associated microswitches 56 and 58 respectively. Power is supplied to the thermostatic switch 62 by a line 64.
In use, the thermostatic switch 62 is normally set to operate at 3Q 30P. Below that temperature, the set of contacts connected with the sole-., - , , .,,, . . .. - .. .. .. , . ~

noid 50 will be closed, the contacts connected with solenoid 52 will be open, the armature of solenoid 50 will be retracted, the armature of solenoid 52 will be extended, and *he valve 36 will be open. No power will be supplied to either solenoid since the thermostatic switch contacts associated with solenoid 52 are open and the contacts of microswitch 56 will be open due to engagement of arm 44 with this switch. The over-center spring 48 will main-tain the valve 36 in its open position.
When the temperature in tank 12 rises above 80F because of the entry of hot water into the tank through inlet 20, the second set of contacts of thermostatic switcll 62 will close and the first set will open. Solenoid 52 will be energized to swing arm 44 to a position where valve 36 is closed.
Simultaneously, microswitch 58 will be opened by arm 44 and solenoid 52 will be deenergized. The parts will be retained in their positions by over-center spring 48. The reverse occurs when the temperature falls below 80F so that -the valve will open under such temperature conditions.
As illustrated in Figure 2, the tank 12 and its cover 18 are pro- -vided with a layer of insulation 66 which acts to retain the heat of the waste water in the tank.
The illustrated unit is adapted to be installed in a house with the waste water inlet 20 connected to receive waste water from, for example, the kitchen sink, dishwasher, bath tub and so on. The waste water drain is connected to the conventional waste water drain of the house. Fresh water -inlet 28 receives cold water from the normal house lines and fresh water outlet 30 is connected to the inlet of the conventional house hot water tank. -The overflow 16 insures that no excess of waste water will be present in the holding tank 12. The tube 34 surrounding the overflow pipe 16 causes cooler water from adjacent the bottom of the tank to discharge from the overflow 16 rather than hot water from adjacent the top as would otherwise be the case.
While the presently described embodiment is a separate unit adapted - i -1~4094S
to be installed per se in a house, other embodiments may, if desired, be coupled physically to or may form a part of the household hot water tank or certain appliances such as dishwashers and washing machines that use large quantities of hot water.

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A waste water heat recovery unit comprising: a holding tank having a waste water inlet and a waste water drain; a fresh water duct providing a fresh water passage through the holding tank in heat exchange relationship with waste water retained therein; a valve for opening and closing said waste water drain; and thermostatic control means for closing said valve in response to a temperature in the tank greater than a predetermined tempera-ture and for opening said valve in response to a temperature in the holding tank less than said predetermined temperature.
2. A unit according to claim 1 wherein said holding tank is insulated.
3. A unit according to claim 2 wherein said fresh water duct comprises a coil mounted within said tank.
4. A unit according to claim 1, 2 or 3 wherein said valve is a slide valve including a plate adapted to slide on a bottom wall of the tank into and out of valve open and valve closed positions.
5. A unit according to claim 1 wherein said thermostatic control means comprise solenoid means for opening and closing said valve and thermostatic switch means for actuating said solenoid means in accordance with the internal temperature of said tank.
6. A unit according to claim 5 including switch means for deenergizing said solenoid means following opening or closing of said valve thereby.
7. A unit according to claim 1 including overflow means in said tank for draining to said drain any excess of waste water in the tank.
8. A unit according to claim 7 including means associated with said overflow means for causing the overflow to drain cooler water from adjacent the bottom of said tank.
9. In a building having a waste water drain, a fresh water supply and a hot water tank, a waste water heat recovery unit comprising: a holding tank with an inlet and an outlet connected to said waste water drain respectively to receive waste water therefrom and to discharge waste water thereto; a fresh water duct providing a fresh water passage through said holding tank and connected to receive fresh water from said fresh water supply and supply fresh water to said hot water tank, said passage being in heat exchange relationship with waste water retained in said tank; a valve for opening and closing the waste water outlet from said tank; and thermostatic control means for closing said valve in response to a temperature in the tank greater than a predetermined temperature and for opening said valve in response to a temperature in the holding tank less than said predetermined temperature.
10. The invention according to claim 9 wherein said tank is insulated.
CA247,783A 1976-03-12 1976-03-12 Waste water heat recovery unit Expired CA1040945A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA247,783A CA1040945A (en) 1976-03-12 1976-03-12 Waste water heat recovery unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CA247,783A CA1040945A (en) 1976-03-12 1976-03-12 Waste water heat recovery unit

Publications (1)

Publication Number Publication Date
CA1040945A true CA1040945A (en) 1978-10-24

Family

ID=4105449

Family Applications (1)

Application Number Title Priority Date Filing Date
CA247,783A Expired CA1040945A (en) 1976-03-12 1976-03-12 Waste water heat recovery unit

Country Status (1)

Country Link
CA (1) CA1040945A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2471565A1 (en) * 1979-12-17 1981-06-19 Pelletier Jean Michel Waste water heat recuperator - is double tank with heat from waste water transferred to water which is used in further heating circuit
EP0058636A1 (en) * 1981-02-16 1982-08-25 W R G Systeme Aktiengesellschaft Apparatus for recovery of heat from waste water and method of its operation
US20110155366A1 (en) * 2009-12-03 2011-06-30 Joshua Brunn Grey water heat recovery system
DE102012104278B3 (en) * 2012-05-16 2013-07-18 Willi Brunner Heat recovery device and its use

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2471565A1 (en) * 1979-12-17 1981-06-19 Pelletier Jean Michel Waste water heat recuperator - is double tank with heat from waste water transferred to water which is used in further heating circuit
EP0058636A1 (en) * 1981-02-16 1982-08-25 W R G Systeme Aktiengesellschaft Apparatus for recovery of heat from waste water and method of its operation
US20110155366A1 (en) * 2009-12-03 2011-06-30 Joshua Brunn Grey water heat recovery system
DE102012104278B3 (en) * 2012-05-16 2013-07-18 Willi Brunner Heat recovery device and its use
DE202013003151U1 (en) 2012-05-16 2013-08-23 Willi Brunner Heat recovery device and its use
EP2664859A2 (en) 2012-05-16 2013-11-20 Willi Brunner Heat recovery device and its use

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