GB2589112A - Water heater for use in a plumbing system - Google Patents

Water heater for use in a plumbing system Download PDF

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Publication number
GB2589112A
GB2589112A GB1916894.7A GB201916894A GB2589112A GB 2589112 A GB2589112 A GB 2589112A GB 201916894 A GB201916894 A GB 201916894A GB 2589112 A GB2589112 A GB 2589112A
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GB
United Kingdom
Prior art keywords
water
water heater
heater unit
heating
heating means
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.)
Pending
Application number
GB1916894.7A
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GB201916894D0 (en
Inventor
Patrick Conway Sean
Steven Harman Nicholas
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.)
Kohler Mira Ltd
Original Assignee
Kohler Mira Ltd
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 Kohler Mira Ltd filed Critical Kohler Mira Ltd
Priority to GB1916894.7A priority Critical patent/GB2589112A/en
Publication of GB201916894D0 publication Critical patent/GB201916894D0/en
Publication of GB2589112A publication Critical patent/GB2589112A/en
Pending legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H9/00—Details
    • F24H9/20—Arrangement or mounting of control or safety devices
    • F24H9/2007—Arrangement or mounting of control or safety devices for water heaters
    • F24H9/2014—Arrangement or mounting of control or safety devices for water heaters using electrical energy supply
    • F24H9/2028—Continuous-flow heaters
    • 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
    • F24D19/00—Details
    • F24D19/10—Arrangement or mounting of control or safety devices
    • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
    • F24D19/1051—Arrangement or mounting of control or safety devices for water heating systems for domestic hot water
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H1/00—Water heaters, e.g. boilers, continuous-flow heaters or water-storage heaters
    • F24H1/10—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium
    • F24H1/101—Continuous-flow heaters, i.e. heaters in which heat is generated only while the water is flowing, e.g. with direct contact of the water with the heating medium using electric energy supply
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/10—Control of fluid heaters characterised by the purpose of the control
    • F24H15/174—Supplying heated water with desired temperature or desired range of temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F24H15/212—Temperature of the water
    • F24H15/215—Temperature of the water before heating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F24H15/238—Flow rate
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
    • F24H15/355—Control of heat-generating means in heaters
    • F24H15/37—Control of heat-generating means in heaters of electric heaters
    • 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
    • F24D2220/00—Components of central heating installations excluding heat sources
    • F24D2220/04—Sensors
    • F24D2220/042—Temperature sensors
    • 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
    • F24D2220/00—Components of central heating installations excluding heat sources
    • F24D2220/04—Sensors
    • F24D2220/044—Flow sensors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/20—Control of fluid heaters characterised by control inputs
    • F24H15/281—Input from user
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
    • F24H15/00—Control of fluid heaters
    • F24H15/40—Control of fluid heaters characterised by the type of controllers
    • F24H15/414—Control of fluid heaters characterised by the type of controllers using electronic processing, e.g. computer-based
    • F24H15/45—Control of fluid heaters characterised by the type of controllers using electronic processing, e.g. computer-based remotely accessible

Abstract

A water heating unit 1 suitable for a plumbing system, the unit comprising an inlet 2, an outlet 3, a heating chamber 4 situated between the inlet and outlet , a means of heating flowing water 5 and flow 6 and temperature 7 sensors located along the inlet which connect to a control circuit 8 to activate the heating means when the flow sensor detects a flow of water and the temperature detected is below a predetermined value. The heating means may be electric and may be located at least partially within the heating chamber. There may be a first and second heating means which may be activated simultaneously or separately, potentially activated in response to first and second predetermined measured temperature values respectively. The second temperature value may be lower than the first. The heating power provided by each heating means may differ, potentially with the second power being higher than the first. The temperature sensor may be a thermistor and the flow sensor, a flow switch or thermal dissipation sensor. A plumbing system utilising the water heater is also claimed.

Description

WATER HEATER FOR USE IN A PLUMBING SYSTEM
This disclosure relates to a water heater for use in a plumbing system such as an ablutionary system or a heating system. The disclosure also relates to plumbing systems, including ablutionary systems or heating systems, comprising such a water heater.
An electric shower system is an example of an ablutionary system. An electric shower system typically includes a wall-mounted unit containing an instantaneous water heater. The instantaneous water heater comprises a heating chamber containing one or more heating elements operable to heat water passing through the heating chamber. An inlet communicating with the heating chamber is connected to a cold water supply. A shower head is provided in fluid communication with an outlet. The wall-mounted unit is provided with controls that allow a user to control the temperature of the water emitted from the shower head.
Variations in cold water supply temperature can adversely affect the operation of an electric shower system, resulting in a less satisfying experience for the user. If the cold water supply temperature falls, then the difference between the cold water supply temperature and a user's desired shower temperature will increase. To continue delivering water at the user's desired shower temperature, there will typically be a drop in flow rate. The drop in flow rate may result in the user having a less satisfying showering experience.
A first aspect provides a water heater unit for use in a plumbing system, the water heater unit comprising: an inlet, the inlet being configured to receive, in use, water from a water supply, an outlet; and a heating chamber disposed between the inlet and the outlet and one or more heating means operable to heat, in use, a flow of water passing through the heating chamber; wherein the water heater unit further comprises: a flow sensor operable to detect a flow of water through the inlet; and a temperature sensor operable to measure the temperature of the flow of water through the inlet; wherein the flow sensor and the temperature sensor are operably connected to a control circuit operable to control operation of the heating means, wherein the control circuit activates one or more of the heating means to heat the flow of water passing through the heating chamber, in use, when the flow sensor detects a flow of water through the inlet and the temperature of the flow of water through the inlet measured by the temperature sensor is below a predetermined value.
When the flow of water through the inlet measured by the temperature sensor is above the predetermined value, the control circuit may be configured such that the heating means do not operate to heat the flow of water passing through the heating chamber.
The predetermined value may be up to 20°C, up to I5°C, up to 14°C. up to I2°C or up to 10°C. The predetermined value may be at least 3°C, at least 5°C or at least 8°C.
The predetermined value may be approximately 20°C. 19°C, I8°C, I7°C, 16°C, 15°C, I4°C, I3°C, I2°C, 1 1 °C, I0°C, 9°C, 8°C, 7°C, 6°C, 5°C, 4°C, 3°C or less.
Heating the flow of water passing through the heating chamber may be effected using any suitable arrangement of one or more heating means.
For example, one or more heating means may be disposed at least partially within the heating chamber. A plurality of heating means may be provided, e.g. disposed at least partially within the heating chamber. Up to 10 or up to five heating means may be provided, e.g. disposed at least partially within the heating chamber.
In one example implementation, a first heating means and a second heating means may be present, each of the first heating means and the second heating means being arranged to heat, in use, the flow of water passing through the heating chamber. The control circuit may be operably connected to the first heating means and the second heating means. The first heating means and the second heating means may be activated, in use, simultaneously and/or individually.
The first heating means may be activated, in use, when the temperature of the flow of water through the inlet measured by the temperature sensor reaches or falls below a first predetermined temperature. The second heating means may be activated, in use, when the temperature of the flow of water through the inlet measured by the temperature sensor falls below a second predetermined value. The second predetermined value may be lower than the first predetermined value. The second heating means may be activated, in use, in addition to the first heating means (i.e. simultaneously with the first heating means) or instead of the first heating means. The second heating means may provide a higher heating power than the first heating means. The second heating means may provide substantially the same heating power as the first heating means. The second heating means may provide a lower heating power than the first heating means.
The first predetermined value may be up to 20°C, up to 15°C up to 14°C, up to 12°C or up to I0°C. The first predetermined value may be at least 3°C, at least 5°C or at least 8°C.
The first predetermined value may be approximately 20°C, or 19°C, I8°C, I7°C, 16°C, 15°C, 14°C, 13°C, 12°C, 1 1 °C, 10°C, 9°C, 8°C, 7°C, 6°C, 5°C, 4°C, 3°C or less.
The second predetermined value may be up to 20°C, up to I5°C, up to 14°C, up to 12°C or up to 10°C. The second predetermined value may be at least 3°C, at least 5°C or at least 8°C.
The second predetermined value may be approximately 20°C, or 19°C, I8°C, I7°C, 16°C, 15°C. 14°C, 13°C, 12°C, 1 1 °C, 10°C, 9°C, 8°C, 7°C, 6°C, 5°C. 4°C, 3°C or less.
The second predetermined value may be at least 1°C less than the first predetermined value.
The first predetermined value may be between 10°C and 15°C. The second predetermined value may be between 5°C and I2°C.
The one or more heating means may provide at least 1 kW of heating power, up to or at least 1.5 kW of heating power, up to or at least 2kW of heating power, up to or at least 2.5kW of heating power, up to or at least 3kW of heating power, up to or at least 4kW of heating power, and/or up to or at least 5kW of heating power.
One or more of the heating means may comprise an electric heating element.
In an example implementation, the heating means may comprise a single electric heating element operable to provide a heating power of between 2 kW and 3 kW, e.g. a 2.5 kW or 2.6 kW electric heating element.
In another example implementation, the heating means may comprise a first electric heating element and a second electric heating element. The first electric heating element may be operable to provide a heating power of between 1 kW and 2 kW, e.g. approximately 1.3 kW, and the second electric heating element may be operable to provide a heating power of between 2 kW and 3 kW, e.g. approximately 2.6 kW, or vice versa.
The water heater unit may be electrically powered. The water heater unit may be connectable to a standard, domestic mains electricity supply, e.g. via a plug. For instance, the water heater unit may be connectable to a standard, UK domestic mains electricity supply via a plug fitted with a 13A or lower fuse. The water heater unit may be adapted to be connectable to other electricity supplies depending upon the intended site, e.g. country, of use.
The flow sensor may comprise any means for detecting the flow of water. For instance, the flow sensor may comprise a flow switch or a thermal dissipation sensor.
The temperature sensor may comprise any means for measuring the temperature of the flow of water. For example, the temperature sensor may comprise a thermistor.
The water heater unit may be configured to operate with a flow rate through the heating chamber of up to 20 litres per minute, up to IS litres per minute, up to 10 litres per minute or up to 8 litres per minute.
The water heater unit may be configured to operate with a flow rate through the heating chamber of at least 2 litres per minute, at least 3 litres per minute or at least 4 litres per minute The water heater unit may be provided as a single package. The inlet, outlet, heating chamber, one or more heating means, flow sensor, temperature sensor and control circuit may all be contained at least partially within a common housing or casing.
The flow sensor, the temperature sensor and the one or more heating means may each be operably connected to the control circuit by any suitable means, e.g. wired or wireless means or any combinations thereof.
A second aspect provides a plumbing system comprising: a water heater unit according to the first aspect; I5 a water source upstream of the water heater unit, the water source being in fluid communication with the inlet of the water heater unit; and an appliance downstream of the water heater unit, the appliance being in fluid communication with the outlet of the water heater unit.
The plumbing system may comprise an ablutionary system or a heating system.
The water source may comprise a cold water source The water source may comprise a mains water source.
The appliance may be operable to deliver water at a desired temperature A user may select and/or vary the desired temperature, in use.
The appliance may comprise a water heater.
The appliance may comprise an electric shower unit.
The appliance may comprise a boiler for a heating system.
The appliance may comprise an instantaneous water heater for use in the preparation of hot drinks.
The appliance may comprise a mixer valve. The mixer valve may have a first inlet for receiving water supplied from a cold water source and a second inlet for receiving water supplied from a hot water source. The first inlet for receiving water supplied from the cold water source may be in fluid communication with the outlet of the water heater unit. The mixer valve may be a thermostatic mixer valve.
The skilled person will appreciate that except where mutually exclusive, a feature or parameter described in relation to any one of the above aspects may be applied to any other aspect. Furthermore, except where mutually exclusive, any feature or parameter described herein may be applied to any aspect and/or combined with any other feature or parameter described herein.
Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a water heater unit for use in a plumbing system; Figure 2 shows a plumbing system comprising the water heater of Figure I; Figure 3 is a graph illustrating the typical seasonal variation in water supply temperature in the United Kingdom; Figure 4 illustrates the results of a test demonstrating the variation in flow rate delivered by an electric shower unit with variation in water supply temperature; Figures 5 is a graph illustrating the results of a test carried out using an embodiment of a water heater unit to pre-heat the water being supplied to an electric shower unit; and Figure 6 is a graph illustrating the results of another test carried out using another embodiment of a water heater unit to pre-heat the water being supplied to an electric shower unit.
Referring to Figure 1, there is shown schematically a water heater unit 1 for use in a plumbing system. The water heater unit 1 comprises an inlet 2 and an outlet 3. The inlet 2 is configured to receive, in use, water from a water supply, typically a cold water supply such as a mains water supply. A heating chamber 4 is disposed between the inlet 2 and the outlet 3. An electric heating element 5 is arranged to heat, in use, a flow of water passing through the heating chamber 4.
A flow sensor 6 is arranged to detect, in use, a flow of water through the inlet 2. A temperature sensor 7 is arranged to measure, in use, the temperature of the flow of water through the inlet 2. The flow sensor 6 and the temperature sensor 7 are operably connected to a control circuit 8. The control circuit 8 is operably connected to the electric heating element 5. The control circuit 8 is operable to control operation of the electric heating element 5 in response to data received from the flow sensor 6 and the temperature sensor 7. The control circuit 8 activates the electric heating element 5 to heat the flow of water passing through the heating chamber 4, in use, when the flow sensor 6 detects a flow of water through the inlet 2 and the temperature of the flow of water through the inlet 2 measured by the temperature sensor 7 is below a predetermined value.
The water heater unit may include any suitable arrangement of one or more heating means arranged to heat, in use, a flow of water passing through the heating chamber. The one or more heating means may include one or more electric heating elements.
In an example implementation, the water heater unit may comprise a single electric heating element operable to deliver a heating power of approximately 2.5 kW and the water heater unit may be configured such that the predetermined value is 12°C or 14°C.
In another example implementation, the water heater unit may comprise a first electric heating element operable to deliver a heating power of approximately 1.3 kW and a second electric heating dement operable to deliver a heating power of approximately 2.6 kW. The water heater unit may be configured such that the first electric heating element is activated if the water supply temperature is below 14°C or 12°C and the second electric heating element is activated if the water supply temperature is below 8°C or 5°C. During operation, either the first electric heating dement or the second electric heating element may be activated depending upon the water supply temperature as measured by the temperature sensor measuring the flow of water through the inlet of the water heater unit.
The flow sensor may comprise any means for detecting the flow of water. For instance, the flow sensor may comprise a flow switch or a thermal dissipation sensor.
The temperature sensor may comprise any means for measuring the temperature of the flow of water. For example, the temperature sensor may comprise a thermistor.
Conveniently, the water heater unit may be adapted to be connectable to a standard electricity supply at its intended site, e.g. country, of use. For instance, the water heater unit may be adapted to be connectable to a domestic mains electricity supply, e.g. via a plug. For instance, the water heater unit may be connectable to a standard, UK domestic mains electricity supply via a plug fitted with a 13A or lower fuse.
Conveniently, the water heater unit may be provided as a single package. The inlet, outlet, heating chamber, one or more heating means, flow sensor, temperature sensor and control circuit may all be contained at least partially within a common housing or 20 casing.
In another example implementation, the control circuit may be provided in a separate housing.
Figure 2 shows a plumbing system 20 comprising the water heater unit 1. The water heater unit 1 is as described above in relation to Figure I with the features of the water heater unit 1 being labelled using the same reference numerals as in Figure 1.
Upstream of the water heater unit 1 there is a water supply 21. Downstream of the water heater unit 1 there is an appliance 22, which may comprise a water heater and/or may be operable to deliver water at a desired temperature. A user may select and/or vary the desired temperature, in use.
The inlet 2 is in fluid communication with the water supply 21. Typically, the water supply 21 may be a cold water supply such as a mains water supply.
The outlet 3 is in fluid commimication with the appliance 22. The appliance 22 may comprise, for example, an electric shower unit or a boiler for use in heating a residential, commercial or industrial premises.
During operation of the appliance 22, the water heater unit 1 will operate whenever the flow sensor 6 detects a flow of water through the inlet 2 and the temperature of the flow of water through the inlet 2 measured by the temperature sensor 7 is below a predetermined value to pre-heat the water being supplied to the appliance 22. This may have a beneficial effect on the operation of the appliance 22 and/or user experience.
Figure 3 is a graph illustrating the typical seasonal variation in water supply temperature in the United Kingdom. The graph shows data from the Water Distribution Board for the United Kingdom. Average water supply temperature for the United Kingdom, measured in degrees Celsius (°C) is measured on the y-axis. The date is shown on the x-axis. A line 31 plotted on the graph shows the variation in average water supply temperature for the United Kingdom during 2004.
The average water supply temperature for the United Kingdom during 2004 was at a maximum of around 20°C in summer (e.g. June) and was at a minimum of around 5°C in March.
For a typical 9 kW electric shower to deliver water at a user-desired temperature of 40°C from a water supply temperature of 20°C, the flow rate will typically be around 6 litres per minute (L/min). For a typical 9 kW electric shower to deliver the same user-desired temperature of 40°C from a water supply temperature of 5°C, the flow rate must be reduced to around 3.5 L/min. Hence, a user of the electric shower will experience a 40% or more reduction in flow between the annual maximum and minimum water supply temperature. Accordingly, the user may have an appreciably less satisfying shower experience during times when the water supply temperature is reduced.
Figure 4 illustrates the results of a test demonstrating the variation in flow rate delivered by a 9 kW electric shower unit with variation in water supply temperature.
An example embodiment of a water heater unit is positioned downstream of a water supply and upstream of the 9 kW electric shower unit. The 9 kW electric shower unit was set to deliver water at a user-desired temperature of 40°C. In order to keep the user-desired temperature substantially constant, the electric shower unit is configured to control water flow therethrough. The water supply pressure was approximately 1 bar. The water supply temperature was varied across the typical range of UK average water supply temperatures. In this test, the flow sensor and the temperature sensor of the water heater unit were utilised to measure the flow and temperature of water at the inlet respectively. The water heater unit was otherwise turned off, i.e. the heating element(s) was/were not activated at any time.
Referring to Figure 4, temperature, measured in degrees Celsius (°C) is marked on the left-hand y-axis. Flow rate, measured in litres per hour (L/hour), is marked on the right-hand y-axis. Time, measured in seconds, is marked on the x-axis. A first line 41 is a plot of the user-desired (outlet) temperature, which remained substantially constant just below 40°C throughout the duration of the test. A second line 42 is a plot of the flow rate delivered by the electric shower unit. A third line 43 is a plot of the (inlet) temperature measured by the temperature sensor of the water heater unit. The temperature measured by the temperature sensor of the water heater unit is representative of the water supply temperature. There is a clear correlation between variation in the water supply temperature (as measured by the temperature sensor of the water heater unit), i.e. line 42, and the flow rate delivered by the electric shower unit, i.e. line 43.
When the temperature measured by the temperature sensor was at its maximum, 20.7°C, the flow rate delivered by the electric shower unit was 374 L/hour (6.2 L/min). When the temperature measured by the temperature sensor was at its minimum, 4.5°C, the flow rate delivered by the electric shower unit was 215 L/hour (3.6 L/min). In this test, the observed drop in flow rate between the maximum water supply temperature (20.7°C) and the minimum water supply temperature (4.5°C) was around 42%.
Intermediate flow rates were observed at temperatures between the maximum and minimum water supply temperatures. For instance, when the temperature measured by the temperature sensor was 15.5°C the flow rate delivered by the electric shower unit was 331 L/hour (5.5 L/m n). When the temperature measured by the temperature sensor was 9.7°C the flow rate delivered by the electric shower unit was 265 L/hour (4.4 L/min).
Figures 5 and 6 are graphs illustrating the results of tests carried out using example embodiments of a water heater unit to pre-heat the water being supplied to an electric shower unit.
In one test, the results of which are illustrated in Figure 5, an example embodiment of a water heater unit was used to pre-heat the water being supplied to a 9 kW electric shower unit. The water heater unit is positioned downstream of a water supply and upstream of the 9 kW electric shower unit. The 9 kW electric shower unit was set to deliver water at a user-desired temperature of 40°C. In order to keep the user-desired temperature substantially constant, the electric shower unit is configured to control water flow therethrough. The water heater unit has an electric heating dement operable to deliver a heating power of approximately 2.5 kW. The water heater unit was configured such that the electric heating element was activated if the water supply temperature was below 12°C.
The water supply pressure was approximately 1 bar. The water supply temperature was set to 5°C, in order to simulate typical minimum water supply temperature for the UK, which may constitute worst case conditions.
Referring to Figure 5, temperature, measured in degrees Celsius (°C) is marked on the left-hand y-axis. Flow rate, measured in litres per hour (L/hour), is marked on the right-hand y-axis. Time, measured in seconds, is marked on the x-axis A first line 51 is a plot of the user-desired (outlet) temperature, which remained substantially constant just below 40°C throughout the duration of the test. A second line 52 is a plot of the flow rate delivered by the electric shower unit. A third line 53 is a plot of the (inlet) temperature measured by the temperature sensor of the water heater unit.
The temperature measured by the temperature sensor of the water heater unit is representative of the water supply temperature. A fourth line 54 is a plot of the temperature of the water flowing through the outlet of the water heater unit. A fifth line 55 illustrates schematically electric current passing to the electric heating element in the water heater unit. A dashed line 56 indicates the time at which the water heater unit is turned on.
In this test, the water heater unit was turned on after 20 seconds, as indicated by the dashed line 56. Around five seconds later, the electric heating element began to operate to heat the water flowing through the heating chamber, as indicated by a step in line 55, when the electrical current passing to the electric heating element increased from 0 Amps to approximately 9 Amps. Before the electric heating element was turned on, the (inlet) temperature measured by the temperature sensor of the water heater unit and the temperature of the water flowing through the outlet of the water heater unit were both 5°C. After the electric heating element was turned on, the temperature of the water flowing through the outlet of the water heater unit rose from 5°C to around 12°C.
Before the water heater unit was turned on, for the water supply temperature of 5°C, the electric shower unit was delivering 3.88 L/min of water at a temperature of 39.4°C.
With the water heater unit turned on, the temperature of water being supplied to the electric shower unit increased from 5°C to around 12°C. Under these conditions, the electric shower unit delivered 4.89 L/min of water at a temperature of 39.2°C. Thus, operation of the water heater unit to pre-heat the water supplied to the electric shower unit from 5°C to 12°C resulted in an increase of around 26% in flow rate of water delivered by the electric shower unit.
In one test, the results of which are illustrated in Figure 6, an example embodiment of a water heater unit was used to pre-heat the water being supplied to a 9 kW electric shower unit. The water heater unit is positioned downstream of a water supply and upstream of the 9 kW electric shower unit. The 9 kW electric shower unit was set to deliver water at a user-desired temperature of 40°C. In order to keep the user-desired temperature substantially constant, the electric shower unit is configured to control water flow therethrough. The water heater unit has a first electric heating element operable to deliver a heating power of approximately 1.3 kW and a second electric heating element operable to deliver a heating power of approximately 2.6 kW. The water heater unit was configured such that the first electric heating element was activated if the water supply temperature was below 12°C and the second electric heating element was activated if the water supply temperature was below 8°C. During operation, either the first electric heating element or the second electric heating element was activated depending upon the water supply temperature as measured by the temperature sensor measuring the flow of water through the inlet of the water heater unit.
The water supply pressure was approximately I bar. The water supply temperature was varied across the typical range of UK average water supply temperatures.
Referring to Figure 6, temperature, measured in degrees Celsius (°C) is marked on the left-hand y-axis. Current, measured in Amps, is also marked on the left-hand y-axis. Flow rate, measured in litres per hour (L/hour), is marked on the right-hand y-axis. Time, measured in seconds is marked on the x-axis. A first line 61 is a plot of the user-desired (outlet) temperature, which remained substantially constant just below 40°C throughout the duration of the test. A second line 62 is a plot of the flow rate delivered by the electric shower unit. A third line 63 is a plot of the (inlet) temperature measured by the temperature sensor of the water heater unit. The temperature measured by the temperature sensor of the water heater unit is representative of the water supply temperature. A fourth line 64 is a plot of the temperature of the water flowing through the outlet of the water heater unit. A fifth line 65 illustrates schematically electric current passing to the electric heating element in the water heater unit.
As can be seen from Figure 6, there was some reduction in flow rate with decreasing water supply temperature. However, this reduction in flow rate was less significant than discussed above, e.g. in relation to Figures 3 and 4. Accordingly, a user of the electric shower unit will have a more consistent and satisfying experience throughout the year.
When the temperature measured by the temperature sensor was at its maximum, 20.3°C, the flow rate delivered by the electric shower unit was 368 L/hour (6.1 L/min). When the temperature measured by the temperature sensor was at its minimum, 4.5°C, the flow rate delivered by the electric shower unit was 290 L/hour (4.8 L/min). In this test, the observed drop in flow rate between the maximum water supply temperature (20.7°C) and the minimum water supply temperature (4.5°C) was around 21%. This is approximately half of the observed drop in flow rate when the water heater unit was not operational to pre-heat the water supplied to the electric shower unit (i.e. as illustrated in Figure 4 and discussed above).
Intermediate flow rates were observed at temperatures between the maximum and minimum water supply temperatures. For instance, when the temperature measured by the temperature sensor was 15.4°C the flow rate delivered by the electric shower unit was 330 L/hour (5.4 L/min). When the temperature measured by the temperature sensor was 9.3°C the flow rate delivered by the electric shower unit was 290 L/hour (4.8 L/min) When the first electrical heating element is operational, approximately 5 Amps of current pass through it. When the second electrical heating element is operational, approximately 9 Amps of current pass through it.
The use of a water heater unit described herein to pre-heat water supplied to a downstream appliance may be beneficial in a range of applications. Typically, this may help mitigate one or more adverse effects on the performance of the downstream appliance that may arise as a result of a fall in water supply temperature, e.g. due to seasonal variation in water supply temperature.
While the example embodiments described herein have referred mainly to the use of the water heater unit to pre-heat water supplied to a downstream electric shower unit, it will be appreciated that the benefits of the disclosure may be realised when the water heater unit is used to pre-heat water supplied to other downstream appliances.
Generally, the appliance may be operable to deliver water at a desired temperature A user may select and/or vary the desired temperature, in use The appliance may comprise a water heater.
The appliance may comprise a boiler for a heating system.
The appliance may comprise an instantaneous water heater for use in the preparation of hot drinks.
The appliance may comprise a mixer valve. The mixer valve may have a first inlet for receiving water supplied from a cold water source and a second inlet for receiving water supplied from a hot water source. The first inlet for receiving water supplied from the cold water source may be in fluid communication with the outlet of the water heater unit. Thus, variation, e.g. seasonal variation, in the temperature of water received at the first inlet of the mixer valve may be reduced, which may improve the consistency and/or reliability of performance of the mixer valve.
A water heater unit described herein may be installed at the time of installing a plumbing system. Alternatively, a water heater unit described herein may be retro-fitted into an existing plumbing system The above embodiments are described by way of example only. Many variations are possible without departing from the invention.
It will be understood that the invention is not limited to the embodiments above-described and various modifications and improvements can be made without departing from the concepts described herein. Except where mutually exclusive, any of the features may be employed separately or in combination with any other features and the disclosure extends to and includes all combinations and sub-combinations of one or more features described herein.

Claims (19)

  1. CLAIMS1. A water heater unit for use in a plumbing system, the water heater unit comprising: an inlet the inlet being configured to receive, in use, water from a water supply; an outlet and a heating chamber disposed between the inlet and the outlet and one or more heating means operable to heat, in use, a flow of water passing through the heating chamber; wherein the water heater unit further comprises: a flow sensor operable to detect a flow of water through the inlet; and a temperature sensor operable to measure the temperature of the flow of water through the inlet; wherein the flow sensor and the temperature sensor are operably connected to a control circuit operable to control operation of the heating means, wherein the control circuit activates one or more of the heating means to heat the flow of water passing through the heating chamber, in usc, when the flow sensor detects a flow of water through the inlet and the temperature of the flow of water through the inlet measured by the temperature sensor is below a predetermined value.
  2. 2. A water heater unit according to claim 1, wherein the predetermined value is up to 20°C, up to 15°C, up to 14°C, up to 12°C or up to 10°C.
  3. 3. A water heater unit according to claim 1 or claim 2, wherein the predetermined value is at least 3°C, at least 5°C or at least 8°C.
  4. A water heater unit according to claim 1, claim 2 or claim 3, wherein one or more heating means is/arc disposed at least partially within the heating chamber.
  5. S. A water heater unit according to any one of the preceding claims comprising a first heating means and a second heating means, each of the first heating means and the second heating means being arranged to heat, in usc, the flow of water passing through the heating chamber, wherein the control circuit is operably connected to the first heating means and the second heating means and the first heating means and the second heating means is/arc activated, in use, simultaneously and/or individually.
  6. 6. A water heater unit according to claim 5, wherein the first heating is activated, in use when the temperature of the flow of water through the inlet measured by the temperature sensor reaches or fans below a first predetermined temperature and the second heating means is activated, in use, when the temperature of the flow of water through the inlet measured by the temperature sensor falls below a second predetermined value.
  7. 7. A water heater unit according to claim 6, wherein the second predetermined value is lower than the first predetermined value 10
  8. 8. A water heater unit according to claim 5, claim 6 or claim 7, wherein: the second heating means provides a higher heating power than the first heating means; the second heating means provides substantially the same heating power as the first heating means; or the second heating means provides a lower heating power than the first heating means.
  9. 9. A water heater unit according to any one of claims 5 to 8, wherein: the first predetermined value is up to 20°C, up to 15°C, up to I4°C. up to I2°C or up to 10°C; and/or the first predetermined value is at least 3°C, at least 5°C or at least 8°C; and/or the second predetermined value is up to 20°C, up to 15°C, up to 14°C, up to 12°C or up to 10°C; and/or the second predetermined value is at least 3°C, at least 5°C or at least 8°C
  10. 10. A water heater unit according to any one of the preceding claims, wherein the one or more heating means provide at least 1 kW of heating power, up to or at least 1.5 kW of heating power, up to or at least 2kW of heating power, up to or at least 2.5kW of heating power, up to or at least 3kW of heating power, up to or at least 4kW of heating power, and/or up to or at least 5kW of heating power.
  11. 11. A water heater unit according to any one of the preceding claims herein one or more of the heating means may comprise an electric heating dement.
  12. 12. A water heater unit according to any one of the preceding claims wherein the flow sensor comprises a flow switch or a thermal dissipation sensor.
  13. 13. A water heater unit according to any one of the preceding claims, wherein the temperature sensor comprises a thermistor.
  14. 14. A plumbing system comprising: a water heater unit according to any one of claims 1 to 13; a water source upstream of the water heater unit, the water source being in fluid communication with the inlet of the water heater unit; and an appliance downstream of the water heater unit, the appliance being in fluid communication with the outlet of the water heater unit.
  15. 15. A plumbing system according to claim 14, wherein the plumbing system comprises an ablutionary system or a heating system.
  16. 16. A plumbing system according to claim 14 or claim 15, wherein the water source comprises a cold water source.
  17. 17. A plumbing system according to claim 14, claim 15 or claim 16, wherein the appliance is operable to deliver water at a desired temperature.
  18. 18. A plumbing system according to any one of claims 14 to 17, wherein: the appliance comprises a water heater; the appliance comprises an electric shower unit; the appliance comprises a boiler for a heating system; the appliance comprises an instantaneous water heater for use in the preparation of hot drinks; or the appliance comprises a mixer valve, e.g. a thermostatic mixer valve
  19. 19. A plumbing system according to any one of claims 14 to 18, wherein the appliance comprises a mixer valve, the mixer valve having a first inlet for receiving water supplied from a cold water source and a second inlet for receiving water supplied from a hot water source and the first inlet for receiving water supplied from the cold water source is in fluid communication with the outlet of the water heater unit.
GB1916894.7A 2019-11-20 2019-11-20 Water heater for use in a plumbing system Pending GB2589112A (en)

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GB2589112A true GB2589112A (en) 2021-05-26

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4501261A (en) * 1982-06-28 1985-02-26 Toto Limited Instantaneous gas water heater
US20100086289A1 (en) * 2008-09-03 2010-04-08 Johnson Gregg C Modular tankless water heater with precise power control circuitry and structure
WO2016100710A1 (en) * 2014-12-17 2016-06-23 Eemax, Inc. Tankless electric water heater

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4501261A (en) * 1982-06-28 1985-02-26 Toto Limited Instantaneous gas water heater
US20100086289A1 (en) * 2008-09-03 2010-04-08 Johnson Gregg C Modular tankless water heater with precise power control circuitry and structure
WO2016100710A1 (en) * 2014-12-17 2016-06-23 Eemax, Inc. Tankless electric water heater

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