WO2016189458A1

WO2016189458A1 - Heating arrangement for a hot water cylinder

Info

Publication number: WO2016189458A1
Application number: PCT/IB2016/053031
Authority: WO
Inventors: Donald Gregory Reid
Original assignee: Donald Gregory Reid
Priority date: 2015-05-28
Filing date: 2016-05-24
Publication date: 2016-12-01

Abstract

This invention provides for a heating arrangement (10) which is suitable for use in a hot water cylinder. The heating arrangement comprises an element spacing member (40) and a heating element (20) which is, in use, spaced apart from the sidewall (70) by the element spacing member (40). The element spacing member (40) is adapted to position the heating element (20) away from the longitudinal axis and towards an inner wall (70) of the main body of the hot water cylinder. The invention further provides for a hot water cylinder comprising this heating arrangement (10).

Description

HEATING ARRANGEMENT FOR A HOT WATER CYLINDER

INTRODUCTION

THIS invention relates to a heating arrangement, to a hot water cylinder comprising the heating arrangement, and in particular, but not exclusively, to a domestic method of heating water using this heating arrangement.

BACKGROUND

Several hot water cylinder types and configurations are known for use in heating domestic water.

During this time of global warming, carbon emissions taxation, and spiralling electricai costs, it has become critical to find ways of saving electricity. It has been shown that the hot water cylinder (geyser) in a household is the single greatest consumer of electricity. Conventional hot water cylinders, and the heating elements used in these, are relatively inefficient and are known to be huge consumers of power. The issue is compounded by the poor design (relative positions of the heating element, the inlet and the outlet) of known hot water cylinders and the heating arrangements provided in these cylinders, particularly in respect of the usage of the hot water produced by the cylinder.

The residential sector is the major contributor to the critical evening peak electricity demand in South Africa, although it consumes only about a fifth of the country's total electricity used.

According to official reports, the total South African national grid generating capacity is about 42 600 W. Further, it is well known that the domestic load constitutes about 15 % of total electricity demand, but that this number increases to about 35 % of the total generating capacity at peak evening times. This is due to the poor load factor nature of the domestic load which coincides with the evening peak that is more expensive to generate.

The annual load factor deterioration is of growing concern. Several regions of the country frequently experience power cuts which impacts on the affected societies in numerous ways. Some of the immediate consequences include the impact on general economic growth and development, the impact on direct foreign investment, and the impact on security when communities live in darkness.

It has been shown that the heating of water through hot water cylinders is responsible for about 46 % of electricity used in average households. Therefore, in order to safe electricity it is imperative that the household hot water cylinder is targeted for the development of new technologies that are able to deliver a reduction in the total household electricity bill.

To date all attempts to reduce the electrical efficiency of hot water cylinders, or water heating in general, have been focussed on technologies that are at the perimeter of, or outside the hot water cylinder itself. Examples of such technologies include the insulation of hot water cylinders, renewable energy sources such as solar power configurations, and heat pump associated technologies. The initial capital layout associated with these technologies, and the relatively slow return on investment to the user, has been a major contributing factor in the slow uptake of these technologies.

In contrast, there has been no to very little development based on the temperature differential of the water within the hot water cylinder.

Therefore, there remains a need for an improvement in the energy efficiency within conventional hot water cylinders. It is therefore an object of the present invention to provide a saving in the energy consumed by conventional hot water cylinders, at a cost of implementation which compares favourably with the options currently available.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a heating arrangement, suitable for use in a hot water cylinder, wherein the hot water cylinder comprises a main body and opposing sidewalls, with at least one side wail comprising an opening for receiving a heating arrangement, in use, and wherein a longitudinal axis extends from the sidewall opening substantially parallel to an inner wall of the main body, the heating arrangement comprises an element spacing member and a heating element which is, in use, spaced apart from the sidewall by the element spacing member, wherein the element spacing member is adapted to position the heating element away from the longitudinal axis and towards an inner wall of the main body when, in use, the heating arrangement is inserted through the opening and secured to the sidewall of the hot water cylinder. in one embodiment the heating arrangement further comprises a waterproof electrical housing.

The heating arrangement may comprise a conduit suitable for receiving and housing electrical connections, the conduit being connectab!e at one end thereof to the sidewail, and at another end thereof to the waterproof electrical housing.

In one embodiment the element spacing member is an off-set bracket connectab!e to the waterproof electrical housing, the off-set bracket being adapted to position the heating element away from the longitudinal axis and adjacent an inner wall of the main body when, in use, the heating arrangement is inserted through the opening and secured to the sidewail of the hot water cylinder.

In a preferred embodiment the element spacing member is a non-resistive section integrally formed with the heating element.

In a particularly preferred embodiment the heating element is spaced at least 50 mm, at least 75 mm, at least 100 mm, or at least 150 mm away from the longitudinal axis towards an inner wall of the main body.

In a particularly preferred embodiment the heating element is spaced apart from the sidewali by the element spacing member by at least 50 mm, at least 100 mm, at least 150 mm, or at least 200 mm.

In one embodiment the heating arrangement further comprises a securing arrangement for securing the heating arrangement to the sidewail of a hot water cylinder when in use.

Preferably, the securing arrangement comprises an inner plate, and intermediate gasket layer, and an outer face plate.

Preferably, the intermediate gasket layer is made from a non-conductive material. According to a second aspect of the present invention there is provided a hot water cylinder comprising a heating arrangement according to the invention. in a preferred embodiment, the cylinder is a horizontal installation domestic hot water cylinder.

In a particularly preferred embodiment, the cylinder has a capacity of about 100 litres, about 50 litres, or about 200 litres.

According to a third aspect of the present invention there is provided a domestic method of heating water comprising heating water with a hot water cylinder comprising the heating arrangement according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in more detail with reference to the following non-limiting embodiments and figures in which:

Figure 1 shows a side view of a first embodiment of a heating arrangement according to the present invention;

Figure 2 shows a partially sectioned side view of a hot water cylinder comprising a heating arrangement according to the present invention;

Figure 3 shows a side view of a second embodiment of a heating arrangement according to the present invention;

Figure 4 shows a side view of the securing arrangement of the heating arrangement according to the present invention;

Figure 5 shows a side view of the watertight electrical housing of the hot heating arrangement according to the present invention; Figure 6 shows a diagram of a theoretical water temperature spread in a conventional hot water cylinder;

Figure 7 shows a graphical representation of a water temperature experiment performed in identical hot water cylinders comparing a standard 2.0 Kw spiral element with the heating arrangement according to the present invention;

Figure 8 shows a graphical representation of a water temperature experiment in a 100 L hot water cylinder comparing heating element configurations; and

Figure 9 shows a graphical representation of a water temperature experiment in a 150 L hot water cylinder comparing heating element configurations.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

The present invention wilt now be described more fully hereinafter with reference to the accompanying figures, in which some of the non-limiting embodiments of the invention are shown. In the accompanying figures like features are indicated by like reference numerals.

The invention as described hereinafter should not be construed to be limited to the specific embodiments disclosed, with slight modifications and other embodiments intended to be included within the scope of the invention.

Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

As used herein, throughout this specification and in the claims which follow, the singular forms "a", "an" and "the" include the plural form, unless the context clearly indicates otherwise. The terminology and phraseology used herein is for the purpose of description and should not be regarded as limiting. The use of the terms "comprising", "containing", "having", "including", and variations thereof used herein, are meant to encompass the items listed thereafter, and equivalents thereof as well as additional items.

Figure 1 shows a heating arrangement 10 according to a first embodiment of the present invention. The heating arrangement 10 comprises a heating element 20, an off-set bracket 40, a waterproof housing 30, and a securing arrangement 60 which in use is secured to a side wall 72 of the hot water cylinder, as can be seen in Figure 2. The side wall 72 has an opening 74 for receiving the heating arrangement 10.

As can be seen from Figure 1 , the waterproof electrical housing 30 and the heating element 20, which is partly received by the waterproof housing 30 and protrudes therefrom into the surrounding water (not shown) in the hot water cylinder, is spaced apart from the securing arrangement 60 by a significant distance. In addition, the waterproof housing 30, and the heating element 20 connected thereto is in use spaced apart from the securing arrangement 60 by means of the off-set bracket 40.

As can be seen from Figure 2, the bracket 40 is off-set thereby to position the heating element 20 away from the securing arrangement 60, and from a line A-A running through the centre of the hot water cylinder towards an inner wall 70 of the main body of the hot water cylinder. The line A-A defines a longitudinal axis which extends from the centre of the opening 74 in the sidewa!l 72 substantially parallel to an inner wall 70 of the main body of the hot water cylinder. The heating element 20 is spaced away from the longitudinal axis and towards an inner wall 70 of the hot water cylinder on the side thereof that also houses the inlet 80 for receiving cold water, i.e. furthest from the outlet 90 through which hot water is drawn when, in domestic use, water is used to run a bath or take a shower, for example. it will be appreciated by persons skilled in the art that the waterproof electrical housing 30 can have many suitable configurations for receiving electrical communication and for connecting the heating element 20 in a manner that is both waterproof and removable for the purposes of replacement, in the embodiment shown in Figure 1 , the waterproof electrical housing 30 comprises a first bo!t on end plate 32, for receiving the electrical communication, and a second welded or otherwise integral end plate 34 that comprises a threaded bush for receiving a screw-in heating element 20. The joint between the bolt on end plate 32 and the waterproof housing body may be sealed by any suitable means, such a gasket of o-ring of materia! that would sustain a waterproof seal.

The electrical communication between the waterproof electrical housing 30 and the securing arrangement 60 is received in and housed by a conduit 50 that is manufactured from a suitable non-corrosive heat stable material such as stainless steel, or a polymeric material with the appropriate characteristics. The conduit 40 is connected to the securing arrangement 60 and the waterproof electrical housing by means of the appropriate screw on fittings known in the art.

The securing arrangement 60 shown in Figure 1 is a composite structure comprising three distinct layers. The composite securing arrangement comprises an inner interface plate 66 which, when installed, faces the inside of the hot water cylinder (not shown), and therefore also the waterproof electrical housing 30 and the heating element 20. The composite securing arrangement further comprises an intermediate gasket member 64 and an outer face plate 62. As can be seen from Figure 4, the outer face plate 62 comprises several holes for securing the heating arrangement 10 to a hot water cylinder. It will be appreciated that the heating arrangement 10 is configured to be fitted to existing hot water cylinders by removing the existing element and retrofitting the heating element according to the present invention. The interface plate has a machined ridge (not shown) which is pulled into the gasket so as to sea! the securing arrangement. Figure 3 shows a heating arrangement 10 according to a second embodiment of the present invention. The heating arrangement 10 comprises a heating element 20, a securing arrangement 60, and an element spacing member which in this embodiment is in the form of an extended dead end 42. The extended dead end is a non-resistive section which does not generate heat from the flow of electricity through that section. The extended dead end 42 can be formed by any knowm method, but importantly functions to space the heating element away from the sidewal! and away from the longitudinal axis towards an inner wall. The dead end may be a solid bar that is paced inside the heating element tube and which connects to the resistive element wire, or be a composite material. In the embodiment shown in Figure 3, the extended dead end 42 is integrally formed with the heating element 10. The heating arrangement is received through an opening in the sidewall, and secured thereto, as is shown for the first embodiment in Figure 2.

It will be appreciated that the function of the off-set bracket 40 and the non- restrictive section 42 is identical, that is to position the heating element 20 away from the securing arrangement 60, and away from a longitudinal axis towards an inner wall 70 of the main body of the hot water cylinder.

Referring now to the Figures in genera!, but to Figure 6 in particular, it is believed that, without thereby wishing to be bound by theory, that the heating element according to the present invention exploits the way in which water is heated in a hot water cylinder, thereby producing significant electrical energy savings, it is generally believed that the heat spread inside a conventional hot water cylinder design is as is shown in Figure 6. The present invention exploits the relative positions of the inlet and outlet, as will be shown below.

Experiment 1

Figure 7 shows a graphical representation of a water temperature experiment performed in identical hot water cylinders comparing a standard 2.0 Kw spiral element with a 2.0 Kw heating arrangement according to the first embodiment of the present invention. The hot water cylinders used in this experiment were simultaneously filled with water, then heated to and maintained at 60 deg C. The pressure line was closed and the water was drained from the bottom of the geyser (the inlet 80 shown in Figure 2) and the outlet 90 (as shown in Figure 2) was opened to allow air to enter. The temperature of the discharged water was measured at every 5 litres withdrawn, and the results of this experiment are graphically represented in Figure 7.

The heating elements in these experiments were spaced about 75 mm from the longitudinal axis and about 365 mm from the sidewai! of the hot water cylinder.

It will be appreciated by those persons skilled in the art that the cold water that enters through the inlet of the hot water cylinder pushes the hot water above it up and out, so that when a hot water tap is opened the outlet from the hot water cylinder is opened, and as it is a pressurized system, cold water enters through the inlet at the bottom of the hot water cylinder thereby pushing hot water up through the outlet and out of the opened tap. In other words, if you withdraw 20 litres of hot water, 20 litres of cold water enters at the bottom through the iniet.

This is important as the temperature curve of the hot water cylinder now becomes critical. As can be seen from Figure 7, the heating arrangement according to the present invention provides water of a higher temperature in the first 40 litres of water discharged through the inlet. Accordingly, the body of water that rises in the hot water cylinder when hot water is withdrawn through the outlet is at a higher temperature compared to the conventional configuration, and therefore requires less electrical energy to be heated to the set point. This naturally affects when the thermostat cut in, and this is demonstrated in the withdrawal experiments discussed below. Experiment 2

Figure 8 shows a graphical representation of temperature spread experiments performed in a 100 L hot water cylinder comparing the performance of a standard 2.0 Kw heating element with a 2.0 Kw heating arrangement according to the first embodiment of the present invention and with a 2.0 Kw heating element according to the second embodiment of the present invention.

Figure 9 shows a graphical representation of temperature spread experiments performed in a 150 L hot water cylinder comparing the performance of a standard 3.0 Kw heating element with a 2.0 Kw heating arrangement according to the second embodiment of the present invention and with a 3.0 Kw heating element according to the second embodiment of the present invention

The hot water cylinders used in these experiments were filled with water, then heated to and maintained at 60 deg C. The pressure line was closed and the water was drained from the inlet 80 while the outlet 90 was opened to allow air to enter. The temperature of the discharged water was measured at every 5 litres withdrawn, and the results of these experiments are graphically represented in Figures 8 and 9.

It is clear from these Figures that the experiments using the heating arrangements according to the present invention provided water at a higher temperature for the first few litres withdrawn, i.e. for water located towards the lower end, or towards the inlet, of the hot water cylinder.

Experiment 3

The following withdrawal experiments were done to simulate the way heated water is used in a household. Cold water entering through the inlet is constantly moving up in the geyser as hot water is withdrawn through the outlet with the opening of hot water taps. The heating cycle is regulated by way of a thermostat that regulates the temperature by switching the element on and off according to the set point. Equipment used:

2 x 150 litre hot water cylinders

Cylinder 1 : Fitted with a standard 3.0 Kw spiral element.

Cylinder 2: Fitted with a heating arrangement according to the first embodiment of the present invention with a 2.0 Kw element.

Table 1. Withdrawal profile cylinder 2.

Kw/Hr meter Simulation

Time Withdrawal (L)

reading comment

09:30 20 89.41 Adult Shower

09:46 10 89.41 Children's ablutions

10:01 20 89.41 Adult Shower

10:31 5 90.34 Dish Washing

11 :01 5 91.39 Dish Washing

1 :45 20 91.39 Child Shower

12:15 15 91.39 Child Shower

12:40 10 92.43 Dish Washing

13:40 30 94.00 Adult Bath

Time total: Withdrawal Total: Total Kw/hrs

4h 10min 135 litres 4.59 Kw/hrs

Notes:

The final computer temperature reading was 59.60 deg C.

Table 2. Withdrawal profile cylinder 1.

As can be seen from the data presented in Tables 1 and 2 above the hot water cyfinder fitted with a heating arrangement according to the present invention with a 2.0 Kw element consumed 42 % less electrical energy compared to the conventional setup utilizing a 3.0 Kw spiral element. This experiment was conducted with the same 150 litres hot water cylinders under the same conditions. The Kw/Hr's used clearly shows the advantage obtained with the heating arrangement according to the present invention.

Experiment 4

2 x 100 litre hot water cylinders

Cylinder 1: Fitted with a standard 2.0 Kw spiral element

This experiment was of interest because a standard 2.0 Kw spiral element was tested against a heating arrangement according to the present invention also fitted with a 2.0 Kw element. Both cylinders were Kwikot® units.

These experiments were run with two identica! hot water cylinders, identical mains water temperature, and identical ambient temperatures.

Table 3. Withdrawal profile cylinder 2.

Kw/Hr meter Simulation

Time Withdrawal (L)

reading comment

08:40 20 89.41 Adult Shower

08:55 10 89.41 Children's ablutions

09:10 20 89.41 Adult Shower

09:40 5 90.34 Dish Washing

10:10 5 91.39 Dish Washing

10:50 20 91.39 Child Shower

11 :20 15 91.39 Child Shower

11 :35 10 92.43 Dish Washing

12:05 20 94.00 Adult Bath

Time total: Withdrawal Total: Total Kw/hrs

3h 25min 125 litres 4.56 Kw/hrs

Notes:

The computer temperature reading was constant at 58.50 deg C and test ended. Table 4. Withdrawal profile cylinder 1.

As can be seen from the data presented in Tables 3 and 4 above the hot water cylinder fitted with a heating arrangement according to the first embodiment of the present invention with a 2.0 Kw element consumed 31 % less electrical energy compared to the conventional setup fitted with a 2.0 Kw spiral element.

This above description of one of the illustrative embodiments of the invention is to indicate how the invention can be made and carried out. Those of ordinary skill in the art will know that various minor modifications may be made, thereby arriving at further embodiments, but that these embodiments will remain within the scope of the invention. For example, it will be appreciated that the bracket 40 and the conduit 50 may be an integrally formed spacing member that also provides electrical communication to the waterproof electrical housing.

Claims

1. A heating arrangement, suitable for use in a hot water cylinder, wherein: the hot water cylinder comprises a main body and opposing sidewails, with at least one side wall comprising an opening for receiving a heating arrangement, in use, and wherein a longitudinal axis extends from the sidewall opening substantially parallel to an inner wall of the main body, the heating arrangement comprises an element spacing member and a heating element which is, in use, spaced apart from the sidewall by the element spacing member, wherein the element spacing member is adapted to position the heating element away from the longitudinal axis and towards an inner wall of the main body when, in use, the heating arrangement is inserted through the opening and secured to the sidewall of the hot water cylinder.

2. A heating arrangement according to claim 1 , further comprising a waterproof electrical housing.

3. A heating arrangement according to claim 2, wherein the heating arrangement further comprises a conduit suitable for receiving and housing electrical connections, the conduit being connectable at one end thereof to the sidewall, and at another end thereof to the waterproof eiectrica! housing.

4. A heating arrangement according to claim 3, wherein the element spacing member is an off-set bracket connectable to the waterproof electrical housing, the off-set bracket being adapted to position the heating element away from the longitudinal axis and adjacent an inner wall of the main body when, in use, the heating arrangement is inserted through the opening and secured to the sidewal! of the hot water cylinder.

5. A heating arrangement according to claim 1 , wherein the element spacing member is a non-resistive section integrally formed with the heating element.

6. A heating arrangement according to any one of the preceding claims, wherein the heating element is spaced at least 50 mm, at least 75 mm, at least 100 mm, or at least 150 mm away from the longitudinal axis towards an inner wall of the main body.

7. A heating arrangement according to any one of the preceding claims, wherein the heating element is spaced apart from the sidewal! by the element spacing member by at least 50 mm, at least 100 mm, at least 150 mm, or at least 200 mm.

8. A heating arrangement according to any one of the preceding claims, further comprising a securing arrangement for securing the heating arrangement to the sidewaii of a hot water cylinder when in use.

9. A heating arrangement according to claim 8, wherein the securing arrangement comprises an inner plate, and intermediate gasket layer, and an outer face plate.

10. A heating arrangement according to claim 9, wherein the intermediate gasket layer is made from a non-conductive material.

11. A hot water cylinder comprising a heating arrangement according to any one of claims 1 to 10.

12. The hot water cylinder according to claim 11 , wherein the cylinder is a horizontal installation domestic hot water cylinder.

13. The hot water cylinder according to claim 12, wherein the cylinder has a capacity of about 100 litres, about 150 litres, or about 200 litres. A domestic method of heating water comprising heating water with a hot water cylinder comprising heating water in a hot water cylinder comprising the heating arrangement according to any one of claims 1 to 10.