WO2018117823A1 - Tap water preparing device and method therefor - Google Patents

Tap water preparing device and method therefor Download PDF

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Publication number
WO2018117823A1
WO2018117823A1 PCT/NL2017/050849 NL2017050849W WO2018117823A1 WO 2018117823 A1 WO2018117823 A1 WO 2018117823A1 NL 2017050849 W NL2017050849 W NL 2017050849W WO 2018117823 A1 WO2018117823 A1 WO 2018117823A1
Authority
WO
WIPO (PCT)
Prior art keywords
tap water
heat exchanger
shut
refrigerant
preparing device
Prior art date
Application number
PCT/NL2017/050849
Other languages
French (fr)
Inventor
Marcel KLOOTWIJK
Original Assignee
Energie Totaal Projecten B.V.
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 Energie Totaal Projecten B.V. filed Critical Energie Totaal Projecten B.V.
Priority to EP17822484.6A priority Critical patent/EP3555531A1/en
Publication of WO2018117823A1 publication Critical patent/WO2018117823A1/en

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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
    • F24D17/0073—Arrangements for preventing the occurrence or proliferation of microorganisms in the water
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/02—Treatment of water, waste water, or sewage by heating
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2303/00—Specific treatment goals
    • C02F2303/04—Disinfection
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2307/00—Location of water treatment or water treatment device
    • C02F2307/06—Mounted on or being part of a faucet, shower handle or showerhead
    • E—FIXED CONSTRUCTIONS
    • E03—WATER SUPPLY; SEWERAGE
    • E03C—DOMESTIC PLUMBING INSTALLATIONS FOR FRESH WATER OR WASTE WATER; SINKS
    • E03C1/00—Domestic plumbing installations for fresh water or waste water; Sinks
    • E03C2001/005—Installations allowing recovery of heat from waste water for warming up fresh water

Definitions

  • the invention relates to a tap water preparing device according to the preamble of Claim 1.
  • the invention furthermore relates to a method for a tap water preparing device according to Claim 15.
  • Tap water preparing devices for heating cold tap water (drinking water) in order to be used for hygiene purposes are generally known and are mainly used in three forms:
  • Heat delivery sets often used in district heating, wherein the cold tap water is heated in a heat exchanger using hot water from the heating network.
  • the temperature of warm tap water only needs to be 40°C to 45°C. However, in this temperature range, there is a strong development of the Legionella bacteria.
  • the tap water in the tap water preparing devices is heated to a temperature of approximately 55°C to approximately 60°C, so that the bacteria dies.
  • producing such a high temperature leads to considerable energy losses during generation, transport and storage of the tap water.
  • a tap water preparing device for heating cold tap water to warm tap water, comprising a heat exchanger, a supply connection for cold tap water in a primary circuit of the heat exchanger, a delivery connection for warm tap water from the primary circuit of the heat exchanger, a sensor for determining flow of water through the delivery connection, and a heat source for heating the incoming tap water, wherein the heat source is located in the heat exchanger, characterized in that the tap water preparing device is provided with cooling means for controllably cooling the heat exchanger and the tap water located in the primary circuit, wherein the cooling means are configured to cool the heat exchanger and the tap water located in the primary circuit to a temperature of 25°C or lower.
  • a heating temperature of the heat exchanger of approximately 40°C to approximately 45°C is sufficient.
  • Such a relatively low temperature can be generated with much higher efficiency than the high temperatures of 55°C to 60°C which are common in the prior art.
  • the resulting prevention of heat losses can quickly lead to a 10-20% reduction in the total energy consumption.
  • the invention relates to a method for a tap water preparing device for heating cold tap water to warm tap water, comprising a heat exchanger, a supply connection for cold tap water in a primary circuit of the heat exchanger, a delivery connection for warm tap water from the primary circuit of the heat exchanger, and a heat source for heating the incoming tap water in the primary circuit, wherein the heat source is located in the heat exchanger, wherein the method comprises:
  • Figure 1 diagrammatically shows a tap water preparing device according to an embodiment
  • Figure 2 diagrammatically shows a tap water preparing device according to a further embodiment
  • Figure 3 diagrammatically shows a tap water preparing device according to an embodiment
  • Figure 4 diagrammatically shows a tap water preparing device according to an embodiment.
  • Figure 1 diagrammatically shows a tap water preparing device according to an embodiment.
  • the warm tap water preparing device 100 shown in the figure comprises a heat exchanger 1, a connection to a supply pipe 2 with cold tap water, a connection to a delivery pipe 7 to a warm tap water delivery point, a sensor 3 to detect the shut-off or flow S of the warm tap water, a control unit 4, an inlet 6 of hot circulating water, a valve 5 in the inlet with hot circulating water, an outlet 8 of the circulating water, a branch pipe 9 in the delivery pipe and a valve 10 in the branch pipe.
  • a primary circuit is provided for tap water to pass through and a secondary circuit of hot circulating water, for example originating from district heating, is used as heat source for heating the tap water.
  • a secondary circuit of hot circulating water for example originating from district heating, is used as heat source for heating the tap water.
  • the circulating water is fed in via inlet 6 and discharged through outlet 8.
  • the water in the delivery pipe 7 starts flowing towards the warm tap water delivery point, while at the same time cold tap water is supplied from inlet pipe 2.
  • the sensor 3 which is connected to the control unit 4 (indicated by the dashed line between sensor 3 and control unit 4) detects said flow S.
  • the control unit 4 opens the valve 5 in the inlet 6 of hot circulating water (denoted by the dashed line between valve 5 and control unit 4).
  • hot water of for example 50°C flows from the inlet 6 of hot circulating water through the heat exchanger 1 as a heating flow.
  • the primary circuit with cold tap water is heated to
  • the control unit 4 closes the valve 5 in the inlet 6 of hot circulating water on the basis of the detection of the sensor 3, as a result of which the supply of hot circulating water stops.
  • the control unit 4 is connected to the valve 10 in the branch pipe 9, denoted by the dashed line between valve 10 and control unit 4. After a predetermined waiting time, the control unit 4 opens the valve 10 in the branch pipe during a cooling period, in which cold tap water flows through the heat exchanger 1 and thus cools the heat exchanger 1 and the tap water located therein to a temperature of 25°C or lower, at which there is no longer unacceptable development of the
  • the tap water used for the cooling is discharged to an outlet 11.
  • the control unit 4 is provided with a time control for determining at least the waiting time and optionally the cooling period.
  • the waiting time can be determined, on the one hand, to prevent the need for unnecessary cooling and heating of the tap water in the event of repeatedly tapping heated water at short intervals and, on the other hand, to prevent unacceptable development of Legionella from taking place, which is dependent on the temperature of the tap water in the heat exchanger and, inter alia, on the water quality of the incoming cold tap water.
  • the waiting time could be selected to be, for example, between 15 minutes and approximately 90 minutes.
  • Existing norms for cooling warm water in a warm water delivery pipe may also be taken into account. In the Netherlands, for example, this is subject to a norm that the stationary water in the delivery pipe is cooled to 25°C after 45 minutes.
  • control unit 4 comprises a time relay for controlling said waiting time and, optionally, the cooling period.
  • Figure 2 diagrammatically shows a tap water preparing device 101 according to a further embodiment.
  • the tap water preparing device 101 additionally comprises a temperature sensor 12 which is connected to the control unit 4 in order to transmit a temperature signal, denoted by the dashed line between temperature sensor 12 and control unit 4.
  • the temperature sensor 12 is configured to measure the temperature of the heat exchanger 1 and the volume of tap water that it contains.
  • FIG. 3 diagrammatically shows a tap water preparing device according to an embodiment.
  • the warm tap water preparing device 102 shown in the figure comprises a heat exchanger 1, a connection to an inlet pipe 2 with cold tap water, a connection to a delivery pipe 7 to a warm tap water delivery point, a sensor 3 to detect the shut-off or flow S of the warm tap water, a control unit 4, an inlet 6 of hot circulating water, a valve 5 in the inlet with hot circulating water, an outlet 8 of the circulating water.
  • an external cooling body 13 which is thermally coupled to the heat exchanger 1 is provided as cooling means.
  • no tap water is thus used as coolant.
  • heat is removed by dissipation from the cooling body 13 to the surroundings. After the flow of warm tap water in the delivery pipe 7 stops, the cooling body 13 removes heat to the surroundings, for example the ambient air. As a result, the heat exchanger 1 and the volume of tap water it contains are cooled.
  • a fan 14 may be provided in order to create an air flow around the cooling body 13.
  • the fan 14 is connected to the control unit 4, as denoted by the dashed line between fan 14 and control unit 4.
  • the fan 14 is started by the control unit 4 at a predetermined time after stopping the flow of warm tap water in delivery pipe 7, on the basis of the detection of the flow sensor 3.
  • the tap water preparing device 102 may be provided with a temperature sensor 12 for measuring the temperature of the heat exchanger and the tap water located therein.
  • the temperature sensor is connected to the control unit as has already been explained with reference to Figure 2.
  • Figure 4 diagrammatically shows a tap water preparing device 103 according to an embodiment.
  • the heating medium is not hot water, but refrigerant.
  • the secondary circuit of the heat exchanger 1 is connected to an inlet 15 with hot, liquid or gaseous refrigerant at high pressure and an outlet 16 with liquid refrigerant at high pressure.
  • the inlet 15 and outlet 16 are connected to one another.
  • the secondary circuit or the inlet 15 with liquid or gaseous refrigerant at high pressure has a branch to an outlet pipe 17 for gaseous refrigerant at low pressure.
  • the outlet pipe 17 for gaseous refrigerant is connected to a (vacuum) compressor (not shown) for achieving a low pressure in the outlet pipe 17.
  • a first shut-off valve 18, second shut-off valve 19 and third shut-off valve 20, respectively, are accommodated in each of the inlet 15, outlet 16 and outlet pipe 17 for refrigerant.
  • the first, second and third shut-off valves 18, 19, 20 are each connected to the control unit 4 as denoted by the respective dashed lines between first, second and third shut-off valve 18, 19, 20 and control unit.
  • the cold tap water is heated to approximately 45°C, while at the same time gaseous refrigerant supplied to the secondary circuit of the heat exchanger condenses (and the formed condensate cools) or the supplied liquid refrigerant cools.
  • the resulting cooled, liquid refrigerant flows towards outlet 16.
  • the pressure prevailing in the secondary circuit for the gaseous refrigerant at high pressure corresponds in this step to the condensation pressure associated with the condensation temperature of the refrigerant used.
  • the control unit 4 closes the first and second shut-off valves 18 and 19, as a result of which the supply of refrigerant at high pressure stops, while refrigerant at high pressure which is present in the secondary circuit comes to a halt. After a predetermined time, the control unit 4 opens the third shut-off valve to the outlet pipe 17 for gaseous refrigerant at low pressure, as a result of which the pressure of the refrigerant in the secondary circuit of the heat exchanger 1 drops.
  • the liquid refrigerant present in the secondary circuit begins to evaporate causing heat to be extracted from the heat exchanger 1 and the volume of tap water it contains, as a result of which the temperature drops further.
  • the third shut-off valve 20 can be closed by the control unit 4.
  • the heat exchanger 1 and the volume of water that the primary circuit of the heat exchanger contains can be cooled to a temperature which is lower than both the ambient temperature and the temperature of the cold tap water which is fed in. This slows the development of the Legionella bacteria yet further.
  • refrigerants can be used, as will be known to the person skilled in the art. Mentioned by way of example are: R134A, R410A, carbon dioxide (C0 2 ), R1234 and water (H2O), but the refrigerants are not limited to these examples. It should be noted that hot air (combustion gases) or an electrical heating element is also possible as an alternative heat source in addition to hot circulating water or refrigerant. The person skilled in the art will understand that such heat sources can be used in a similar way to the hot circulating water or the refrigerant. The person skilled in the art will also understand that the invention can be used in the same way as described above in the event that these alternative heat sources are used.

Abstract

The invention relates to a tap water preparing device for heating cold tap water, comprising a heat exchanger, a supply connection for cold tap water in a primary heat exchanger circuit, a delivery connection for warm tap water from the primary circuit, and a heat source for heating tap water in the primary circuit, wherein the heat source is located in the heat exchanger and is provided with cooling means for controllably cooling the heat exchanger and the tap water located in the primary circuit. The invention furthermore relates to a method comprising: allowing tap water to flow through the primary circuit of the heat exchanger; heating the flowing tap water to warm tap water in the primary circuit of the heat exchanger; interrupting the flow so that tap water no longer flows; subsequently cooling the heat exchanger and warm tap water located in the primary circuit of the heat exchanger to a temperature equal to or lower than 25°C.

Description

Tap water preparing device and method therefor Technical field
The invention relates to a tap water preparing device according to the preamble of Claim 1. The invention furthermore relates to a method for a tap water preparing device according to Claim 15.
Prior art
Tap water preparing devices for heating cold tap water (drinking water) in order to be used for hygiene purposes are generally known and are mainly used in three forms:
• Central-heating boilers, in which cold tap water is heated in a heat exchanger through the combustion of gas or oil.
• Electrically heated boiler tanks, in which the cold tap water is heated using electrical heating elements.
· Heat delivery sets often used in district heating, wherein the cold tap water is heated in a heat exchanger using hot water from the heating network.
For hygiene purposes, the temperature of warm tap water only needs to be 40°C to 45°C. However, in this temperature range, there is a strong development of the Legionella bacteria. In order to prevent contamination with this bacteria, the tap water in the tap water preparing devices is heated to a temperature of approximately 55°C to approximately 60°C, so that the bacteria dies. However, producing such a high temperature leads to considerable energy losses during generation, transport and storage of the tap water.
It is therefore an object of the invention to provide a tap water preparing device and a method therefor which overcome this drawback.
Summary of the invention
The object is achieved by a tap water preparing device for heating cold tap water to warm tap water, comprising a heat exchanger, a supply connection for cold tap water in a primary circuit of the heat exchanger, a delivery connection for warm tap water from the primary circuit of the heat exchanger, a sensor for determining flow of water through the delivery connection, and a heat source for heating the incoming tap water, wherein the heat source is located in the heat exchanger, characterized in that the tap water preparing device is provided with cooling means for controllably cooling the heat exchanger and the tap water located in the primary circuit, wherein the cooling means are configured to cool the heat exchanger and the tap water located in the primary circuit to a temperature of 25°C or lower.
As a result of the fact that the heat exchanger and the volume of cold tap water that this heat exchanger contains are cooled down again within a short time after the production of warm tap water to a temperature at which the Legionella bacteria no longer multiplies, it is no longer necessary to heat the heat exchanger to 55°C-60°C in order to kill the Legionella bacteria. In order to ensure that, under practical circumstances, no unacceptable multiplication of this bacteria takes place while the tap water is at a standstill in the heat exchanger, the heat exchanger and the tap water located therein are actively cooled to a temperature at which the growth of Legionella practically comes to a stop. According to current scientific insights, such a temperature is 25°C or lower. The person skilled in the art will understand that the setting of the temperature may depend on, for example, the quality of the cold tap water or the material used for the heat exchanger.
Instead of the usual relatively high temperature of 55°C to 60°C, a heating temperature of the heat exchanger of approximately 40°C to approximately 45°C is sufficient. Such a relatively low temperature can be generated with much higher efficiency than the high temperatures of 55°C to 60°C which are common in the prior art.
As the heat exchanger and the tap water located therein are cooled to a temperature of approximately 25°C or lower after the production of warm tap water, it is no longer necessary to also heat the heat exchanger during the period in which no warm tap water is produced in order to prevent the development of the Legionella bacteria.
The resulting prevention of heat losses can quickly lead to a 10-20% reduction in the total energy consumption.
In addition, the invention relates to a method for a tap water preparing device for heating cold tap water to warm tap water, comprising a heat exchanger, a supply connection for cold tap water in a primary circuit of the heat exchanger, a delivery connection for warm tap water from the primary circuit of the heat exchanger, and a heat source for heating the incoming tap water in the primary circuit, wherein the heat source is located in the heat exchanger, wherein the method comprises:
allowing tap water to flow through the primary circuit of the heat exchanger; heating the flowing tap water to warm tap water in the primary circuit of the heat exchanger;
interrupting the flow so that tap water no longer flows;
subsequently cooling the heat exchanger and warm tap water located in the primary circuit of the heat exchanger to a temperature equal to or lower than 25°C.
Advantageous embodiments are defined by the dependent claims.
Further features, possible applications and advantages of the invention are apparent from the following description of exemplary embodiments of the invention. Brief description of the drawing
The invention will be described in more detail below with reference to a number of drawings which show a few exemplary embodiments. The drawings are only intended for illustrative purposes and should not be interpreted as limiting the inventive concept which is defined by the attached claims.
In the drawing:
Figure 1 diagrammatically shows a tap water preparing device according to an embodiment;
Figure 2 diagrammatically shows a tap water preparing device according to a further embodiment;
Figure 3 diagrammatically shows a tap water preparing device according to an embodiment; and
Figure 4 diagrammatically shows a tap water preparing device according to an embodiment.
In the description below, the same reference numerals in each case denote identical or similar components in the figures.
Description of embodiments
Figure 1 diagrammatically shows a tap water preparing device according to an embodiment.
The warm tap water preparing device 100 shown in the figure comprises a heat exchanger 1, a connection to a supply pipe 2 with cold tap water, a connection to a delivery pipe 7 to a warm tap water delivery point, a sensor 3 to detect the shut-off or flow S of the warm tap water, a control unit 4, an inlet 6 of hot circulating water, a valve 5 in the inlet with hot circulating water, an outlet 8 of the circulating water, a branch pipe 9 in the delivery pipe and a valve 10 in the branch pipe.
In the heat exchanger, a primary circuit is provided for tap water to pass through and a secondary circuit of hot circulating water, for example originating from district heating, is used as heat source for heating the tap water. In the secondary circuit, the circulating water is fed in via inlet 6 and discharged through outlet 8.
When warm water is required, the water in the delivery pipe 7 starts flowing towards the warm tap water delivery point, while at the same time cold tap water is supplied from inlet pipe 2. The sensor 3 which is connected to the control unit 4 (indicated by the dashed line between sensor 3 and control unit 4) detects said flow S. On the basis of the sensor detection, the control unit 4 opens the valve 5 in the inlet 6 of hot circulating water (denoted by the dashed line between valve 5 and control unit 4). As a result, hot water of for example 50°C flows from the inlet 6 of hot circulating water through the heat exchanger 1 as a heating flow.
In the heat exchanger 1, the primary circuit with cold tap water is heated to
approximately 45°C by thermal coupling with the heating flow in the secondary circuit of hot circulating water. At the same time, the circulating water is cooled to 20°C to 40°C and flows back through outlet 8.
When no more warm tap water is required, the flow of tap water through the inlet pipe 2 and delivery pipe 7 stops. The control unit 4 closes the valve 5 in the inlet 6 of hot circulating water on the basis of the detection of the sensor 3, as a result of which the supply of hot circulating water stops. The control unit 4 is connected to the valve 10 in the branch pipe 9, denoted by the dashed line between valve 10 and control unit 4. After a predetermined waiting time, the control unit 4 opens the valve 10 in the branch pipe during a cooling period, in which cold tap water flows through the heat exchanger 1 and thus cools the heat exchanger 1 and the tap water located therein to a temperature of 25°C or lower, at which there is no longer unacceptable development of the
Legionella bacteria. The tap water used for the cooling is discharged to an outlet 11. The control unit 4 is provided with a time control for determining at least the waiting time and optionally the cooling period.
The waiting time can be determined, on the one hand, to prevent the need for unnecessary cooling and heating of the tap water in the event of repeatedly tapping heated water at short intervals and, on the other hand, to prevent unacceptable development of Legionella from taking place, which is dependent on the temperature of the tap water in the heat exchanger and, inter alia, on the water quality of the incoming cold tap water.
Under practical circumstances, the waiting time could be selected to be, for example, between 15 minutes and approximately 90 minutes. Existing norms for cooling warm water in a warm water delivery pipe may also be taken into account. In the Netherlands, for example, this is subject to a norm that the stationary water in the delivery pipe is cooled to 25°C after 45 minutes.
In an embodiment, the control unit 4 comprises a time relay for controlling said waiting time and, optionally, the cooling period.
Figure 2 diagrammatically shows a tap water preparing device 101 according to a further embodiment.
In this further embodiment, the tap water preparing device 101 additionally comprises a temperature sensor 12 which is connected to the control unit 4 in order to transmit a temperature signal, denoted by the dashed line between temperature sensor 12 and control unit 4. The temperature sensor 12 is configured to measure the temperature of the heat exchanger 1 and the volume of tap water that it contains.
After the flow of warm tap water in the delivery pipe 7 stops, the valve 10 in the branch pipe 9 is opened by the control unit 4 after the predetermined waiting time. Under the control of the control unit 4, the valve 10 in the branch pipe 9 closes again when the temperature of the heat exchanger 1 and the volume of tap water that it contains has decreased to a set temperature, 25°C or lower, detected by the temperature sensor. Figure 3 diagrammatically shows a tap water preparing device according to an embodiment.
The warm tap water preparing device 102 shown in the figure comprises a heat exchanger 1, a connection to an inlet pipe 2 with cold tap water, a connection to a delivery pipe 7 to a warm tap water delivery point, a sensor 3 to detect the shut-off or flow S of the warm tap water, a control unit 4, an inlet 6 of hot circulating water, a valve 5 in the inlet with hot circulating water, an outlet 8 of the circulating water. In this case, an external cooling body 13 which is thermally coupled to the heat exchanger 1 is provided as cooling means. In this embodiment, no tap water is thus used as coolant. In this case, heat is removed by dissipation from the cooling body 13 to the surroundings. After the flow of warm tap water in the delivery pipe 7 stops, the cooling body 13 removes heat to the surroundings, for example the ambient air. As a result, the heat exchanger 1 and the volume of tap water it contains are cooled.
To promote the cooling, a fan 14 may be provided in order to create an air flow around the cooling body 13. The fan 14 is connected to the control unit 4, as denoted by the dashed line between fan 14 and control unit 4. The fan 14 is started by the control unit 4 at a predetermined time after stopping the flow of warm tap water in delivery pipe 7, on the basis of the detection of the flow sensor 3.
In this embodiment, too, the tap water preparing device 102 may be provided with a temperature sensor 12 for measuring the temperature of the heat exchanger and the tap water located therein. The temperature sensor is connected to the control unit as has already been explained with reference to Figure 2.
Figure 4 diagrammatically shows a tap water preparing device 103 according to an embodiment.
In this embodiment, the heating medium is not hot water, but refrigerant.
The secondary circuit of the heat exchanger 1 is connected to an inlet 15 with hot, liquid or gaseous refrigerant at high pressure and an outlet 16 with liquid refrigerant at high pressure. In the secondary circuit, the inlet 15 and outlet 16 are connected to one another.
The secondary circuit or the inlet 15 with liquid or gaseous refrigerant at high pressure has a branch to an outlet pipe 17 for gaseous refrigerant at low pressure. The outlet pipe 17 for gaseous refrigerant is connected to a (vacuum) compressor (not shown) for achieving a low pressure in the outlet pipe 17.
A first shut-off valve 18, second shut-off valve 19 and third shut-off valve 20, respectively, are accommodated in each of the inlet 15, outlet 16 and outlet pipe 17 for refrigerant. The first, second and third shut-off valves 18, 19, 20 are each connected to the control unit 4 as denoted by the respective dashed lines between first, second and third shut-off valve 18, 19, 20 and control unit.
At rest, all three shut-off valves 18, 19, 20 in the refrigerant-conducting pipes 15, 16, 17 are closed.
When warm water is required, the water in the pipe starts flowing towards the tap water delivery point 7, while at the same time cold tap water is supplied to the primary circuit of the heat exchanger 1 from supply pipe 2. The sensor 3 detects this flow S and the control unit 4 opens the first shut-off valve 18 and second shut-off valve 19. As a result, liquid or gaseous refrigerant at high pressure flows from the inlet 15 for high- pressure liquid or gaseous refrigerant through the secondary circuit of the heat exchanger 1 to the outlet 16 for liquid refrigerant. In the primary circuit of the heat exchanger 1, the cold tap water is heated to approximately 45°C, while at the same time gaseous refrigerant supplied to the secondary circuit of the heat exchanger condenses (and the formed condensate cools) or the supplied liquid refrigerant cools. The resulting cooled, liquid refrigerant flows towards outlet 16.
In any case, the pressure prevailing in the secondary circuit for the gaseous refrigerant at high pressure corresponds in this step to the condensation pressure associated with the condensation temperature of the refrigerant used.
When no more warm tap water is required, the flow of warm tap water into the delivery pipe 7 stops. The control unit 4 closes the first and second shut-off valves 18 and 19, as a result of which the supply of refrigerant at high pressure stops, while refrigerant at high pressure which is present in the secondary circuit comes to a halt. After a predetermined time, the control unit 4 opens the third shut-off valve to the outlet pipe 17 for gaseous refrigerant at low pressure, as a result of which the pressure of the refrigerant in the secondary circuit of the heat exchanger 1 drops. Due to the drop in the pressure of the refrigerant in the secondary circuit of the heat exchanger 1, the liquid refrigerant present in the secondary circuit begins to evaporate causing heat to be extracted from the heat exchanger 1 and the volume of tap water it contains, as a result of which the temperature drops further.
If the temperature has dropped sufficiently as measured, for example, by the temperature sensor 12 or as determined by the duration, the third shut-off valve 20 can be closed by the control unit 4.
By using an outlet pipe 17 for low-pressure gaseous refrigerant, the heat exchanger 1 and the volume of water that the primary circuit of the heat exchanger contains can be cooled to a temperature which is lower than both the ambient temperature and the temperature of the cold tap water which is fed in. This slows the development of the Legionella bacteria yet further.
Various refrigerants can be used, as will be known to the person skilled in the art. Mentioned by way of example are: R134A, R410A, carbon dioxide (C02), R1234 and water (H2O), but the refrigerants are not limited to these examples. It should be noted that hot air (combustion gases) or an electrical heating element is also possible as an alternative heat source in addition to hot circulating water or refrigerant. The person skilled in the art will understand that such heat sources can be used in a similar way to the hot circulating water or the refrigerant. The person skilled in the art will also understand that the invention can be used in the same way as described above in the event that these alternative heat sources are used.
Alternative and equivalent embodiments of the present invention are conceivable without departing from the inventive concept, as will be clear to the specialist in the field. In this case, all the features which have been described or illustrated are in themselves or in any combination the subject matter of the invention, irrespective of whether they are summarized in the claims or referred back to and likewise irrespective of how they are phrased or represented in the description or in the drawing, respectively. The inventive concept is only limited by the attached claims.

Claims

Claims
1. Tap water preparing device (100; 101; 102; 103) for heating cold tap water to warm tap water, comprising a heat exchanger (1), a supply connection (2) for cold tap water in a primary circuit of the heat exchanger, a delivery connection (7) for warm tap water from the primary circuit of the heat exchanger, a sensor (3) for determining flow of water through the delivery connection, and a heat source for heating the incoming tap water, wherein the heat source is located in the heat exchanger, characterized in that
the tap water preparing device is provided with cooling means for controllably cooling the heat exchanger (1) and the tap water located in the primary circuit, wherein the cooling means are configured to cool the heat exchanger and the tap water located in the primary circuit to 25°C or lower.
Tap water preparing device according to Claim 1, wherein the cooling means comprise a branch pipe (9) on the delivery connection (7) for warm tap water and a discharge valve (10), wherein the discharge valve is located in the branch pipe.
Tap water preparing device according to Claim 1, wherein the cooling means comprise an external cooling body (13), wherein the cooling body is thermally connected to the heat exchanger (1).
Tap water preparing device according to Claim 3, wherein the external cooling body (13) is provided with a ventilator (14) for creating an air flow along the cooling body.
Tap water preparing device according to Claim 1, wherein the cooling means comprise a refrigerant circuit, wherein the refrigerant circuit is thermally connected to the heat exchanger. 6. Tap water preparing device according to one of the preceding claims, comprising a control unit (4) for controlling the cooling means. Tap water preparing device according to Claim 6, comprising a temperature sensor (12) for determining the temperature of the heat exchanger and/or the tap water located therein, wherein the temperature sensor is connected to the control unit (4) for emitting a temperature signal to the control unit.
Tap water preparing device according to Claim 6 or Claim 7, comprising a shut- off sensor (3) for detecting the absence of flow of the tap water in the primary circuit, wherein the sensor is communicatively connected to the control unit (4) and is configured to emit a shut-off signal if there is no flow of the tap water.
Tap water preparing device according to Claim 8, wherein the control unit is provided with a time control, for emitting a cooling signal at a preset time period after receiving the shut-off signal from the shut-off sensor.
Tap water preparing device according to one of the preceding Claims 1-9, wherein the heat source is one selected from a group comprising an electrical heating element, a gas- or oil-fired heating element, and a secondary circuit for the circulating water.
Tap water preparing device according to one of the preceding Claims 1-9, wherein the heat source comprises a secondary circuit of the heat exchanger provided with a high-pressure inlet pipe (15) and a liquid outlet pipe (16), wherein the inlet pipe and the liquid outlet pipe are connected to one another in the heat exchanger (1) in the secondary circuit and the heat source is provided with a first shut-off valve (18) in the high-pressure inlet pipe and a second shut- off valve (19) in the liquid outlet pipe,
and the cooling means comprise a low-pressure gas outlet pipe (17) for a pressure which is equal to or lower than the pressure associated with an evaporating temperature of the refrigerant of 25°C, wherein the low-pressure gas outlet pipe in the heat exchanger is connected to the secondary circuit between the high- pressure inlet pipe and the liquid outlet pipe, wherein the low-pressure gas outlet pipe is provided with a third shut-off valve (20) for shutting off the connecting pipe.
12. Tap water preparing device according to Claim 11, wherein the control unit (4) is configured to control the first, second and third shut-off valves (18, 19, 20).
13. Tap water preparing device according to Claim 12, wherein the control unit is configured to open the first and second shut-off valves when there is flow of the tap water in the primary circuit, and is configured to close the first and second shut-off valves when there is no flow of tap water in the primary circuit, wherein emitting a cooling signal comprises opening the third shut-off valve.
14. Tap water preparing device according to one of Claims 11-13, wherein the high- pressure inlet pipe is configured to contain refrigerant at a high pressure and a high temperature, the low-pressure gas outlet pipe is configured to contain gaseous refrigerant at a low pressure and low gas temperature, wherein the low pressure is in relative terms lower than the high pressure and the low gas temperature is in relative terms lower than said high temperature.
15. Tap water preparing device according to one of Claims 11-14, wherein the
refrigerant at high pressure and high temperature is a gaseous refrigerant.
16. Tap water preparing device according to one of Claims 11-14, wherein the
refrigerant at high pressure and high temperature is a liquid refrigerant.
17. Method for a tap water preparing device (100; 101; 102; 103) for heating cold tap water to warm tap water, comprising a heat exchanger (1), a supply connection (2) for cold tap water in a primary circuit of the heat exchanger, a delivery connection (7) for warm tap water from the primary circuit of the heat exchanger, and a heat source for heating the incoming tap water in the primary circuit, wherein the heat source is located in the heat exchanger, wherein the method comprises:
allowing tap water to flow through the primary circuit of the heat exchanger; heating the flowing tap water to warm tap water in the primary circuit of the heat exchanger;
interrupting the flow so that tap water no longer flows;
subsequently cooling the heat exchanger and warm tap water located in the primary circuit of the heat exchanger to a temperature equal to or lower than
25°C.
Method according to Claim 17, wherein the cooling begins at a predetermined time after interrupting the flow of the tap water.
Method according to Claim 18, wherein the cooling is preceded by:
detection by a shut-off sensor of the absence of flow of the tap water through the primary circuit; emitting a shut-off signal that there is no flow of the tap water, and determining the predetermined time on the basis of the emitted shut-off signal.
20. Method according to one of Claims 17-19, comprising determining the
temperature of the heat exchanger. 21. Method according to Claim 20, wherein the cooling takes place up to a
predetermined temperature equal to or lower than 25°C.
22. Method according to one of Claims 17-21, wherein heating the flowing tap water to warm tap water in the heat exchanger takes place by supplying refrigerant at a high pressure and a high temperature into a secondary circuit as heat source, wherein the tap water is heated and the refrigerant cools and, to the extent supplied in gaseous form, condenses to liquid refrigerant, wherein the high pressure corresponds to at least the condensation pressure of the refrigerant at the condensation temperature;
during interruption of the flow of tap water in the primary circuit, interrupting the flow of the gaseous and liquid refrigerant through the secondary circuit of the heat exchanger so that liquid refrigerant is located in the secondary circuit of the heat exchanger; and subsequently cooling the heat exchanger and warm tap water in the secondary circuit comprises evaporating the liquid refrigerant present in the heat exchanger.
Method according to Claim 22, wherein the refrigerant is supplied at high pressure and high temperature through an inlet pipe which can be shut off by a first shut-off valve, the liquid refrigerant is discharged through a liquid outlet pipe which can be shut off by a second shut-off valve, wherein the inlet pipe and outlet pipe are connected to one another by the secondary circuit of the heat exchanger, and the evaporated refrigerant is discharged through a low-pressure gas outlet pipe which is connected to the secondary circuit and can be shut off by a third shut-off valve thereof, wherein the method comprises:
opening the first and second shut-off valves in order to supply refrigerant at high pressure and high temperature through the inlet pipe and discharge liquid refrigerant through the liquid outlet pipe, respectively, while the third shut-off valve is closed during heating of the flowing cold tap water to warm tap water in the primary circuit of the heat exchanger;
shutting off the first and second shut-off valves during interruption of the flow of the tap water in the primary circuit;
opening the third shut-off valve during evaporation of the liquid refrigerant present in the secondary circuit of the heat exchanger, while the first and second shut-off valves are closed.
24. Method according to Claim 23, wherein opening the third shut-off valve takes place after a predetermined time after shutting off the flow of the tap water in the primary circuit or after shutting off the first and second shut-off valves.
PCT/NL2017/050849 2016-12-19 2017-12-19 Tap water preparing device and method therefor WO2018117823A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP17822484.6A EP3555531A1 (en) 2016-12-19 2017-12-19 Tap water preparing device and method therefor

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Application Number Priority Date Filing Date Title
NL2018020A NL2018020B1 (en) 2016-12-19 2016-12-19 Tap water heater and method thereof
NL2018020 2016-12-19

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL2023730B1 (en) * 2019-08-29 2021-05-11 Stanislaus Maria Hilckmann Diederik Water tap, building comprising the water tap and method using the water tap

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0837290A1 (en) * 1996-10-16 1998-04-22 Thermovonics Co., Ltd Water cooler
EP1626034A1 (en) * 2004-08-12 2006-02-15 Thomas Bauer Process and system for water treatment
DE202014001131U1 (en) * 2014-02-05 2014-05-12 Robert Kremer Device for drinking water supply for cold and hot water with heat pump
DE202014103193U1 (en) * 2014-07-11 2015-07-15 Better Place GmbH Circulation line for cold water

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0837290A1 (en) * 1996-10-16 1998-04-22 Thermovonics Co., Ltd Water cooler
EP1626034A1 (en) * 2004-08-12 2006-02-15 Thomas Bauer Process and system for water treatment
DE202014001131U1 (en) * 2014-02-05 2014-05-12 Robert Kremer Device for drinking water supply for cold and hot water with heat pump
DE202014103193U1 (en) * 2014-07-11 2015-07-15 Better Place GmbH Circulation line for cold water

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL2023730B1 (en) * 2019-08-29 2021-05-11 Stanislaus Maria Hilckmann Diederik Water tap, building comprising the water tap and method using the water tap

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Publication number Publication date
EP3555531A1 (en) 2019-10-23
NL2018020B1 (en) 2018-06-26

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