IES20120028A2

IES20120028A2 - A rainwater harvesting system

Info

Publication number: IES20120028A2
Application number: IE20120028A
Authority: IE
Inventors: Kevin Hallahan
Original assignee: Kevin Hallahan
Priority date: 2011-01-19
Filing date: 2012-01-19
Publication date: 2012-08-01
Also published as: GB2487480A; IE86689B1; IES86067B2; IE20120029A1; GB201200896D0; GB201100897D0; GB2487480B

Abstract

The present invention relates to rainwater harvesting system for a house, the house having a downpipe and a water storage tank connected to the mains water supply via a mains water valve, the rainwater harvesting system comprising an above-ground rainwater tank in fluid communication with the downpipe, the rainwater tank also being in fluid communication with the water storage tank and comprising a rainwater level sensor; a water purification unit; a pump adapted to draw water from the rainwater tank to the water storage tank through the water purification unit; means to close the mains water valve when rainwater is available in the rainwater tank. <Figure 1>

Description

The present invention relates to a rainwater harvesting system. In particular, it relates to a rainwater harvesting system for a house, the house having a downpipe and a water storage tank connected to the mains water supply via a mains water valve, the rainwater harvesting system comprising an above-ground rainwater tank in fluid communication with the downpipe, the rainwater tank also being in fluid communication with the water 10 storage tank and comprising a rainwater level sensor; a water purification unit; a pump adapted to draw water from the rainwater tank to the water storage tank through the water purification unit; and means to close the mains water valve when rainwater is available in the rainwater tank.

Water conservation is becoming increasingly important. As societies develop and grow, the demand tor water is increasing steadily. In developed countries, treated and in some cases medicated water is supplied in the mains water supply. The treatment of mains water to render it potable is an expensive process and can be very resource intensive. However, much of this expensively treated water is lost in leaky delivery systems and by 20 being used to flush toilets, or to water gardens. It is clear that potable, fluoridated water is not required for flushing toilets or watering gardens.

Many jurisdictions charge their residents for the supply of potable mains water. This helps defray the cost of treating the water, and with water metering, discourages waste.

Methods for the more efficient use of mains water are increasingly popular.

One such method is rainwater harvesting. At its most simple rainwater harvesting comprises gathering rainwater and using it fortasks such as gardening and car-washing.

In this way, treated potable water is not wasted on these tasks.

In recent years, rainwater harvesting has further developed. Sample systems include an underground rainwater tank that is supplied with rainwater from the downpipe of the house in question. The house is also fitted with a secondary plumbing system, separate IE 1 2 0 0 2 8 -2to the main plumbing system, to distribute rainwater from the rainwater tank around the house. Devices that may be connected to the secondary plumbing system include washing machines and toilets. Such systems are said to supply “grey water”. There are a number of disadvantages associated with such systems. For example, there are very large installation costs associated with the buried tank and the secondary plumbing system in the house. Additionally, the garden of the house will be significantly disturbed during the installation of the underground rainwater storage tank. Furthermore, these systems may require the permanent presence of additional pipework on the exterior of the house. This may be considered unsightly and could negatively impact on the value of the property.

Other systems have been developed that provide potable water from harvested rainwater, however, these systems again involve the use of a large underground tank, with the associated cost and inconvenience.

It is an object therefore of the present invention to provide a rainwater harvesting system that overcomes at least some of the above-mentioned problems.

Statements of Invention According to the invention there is provided a rainwater harvesting system for a house, the house having a downpipe and a water storage tank connected to the mains water supply via a mains water valve, the rainwater harvesting system comprising an aboveground rainwater tank in fluid communication with the clownpipe, the rainwater tank also being in fluid communication with the water storage tank and comprising a rainwater level sensor; a water purification unit; a pump adapted to draw water from the rainwater tank to the water storage tank through the water purification unit; means to close the mains water valve when rainwater is available in the rainwater tank characterised in that the fluid communication between the rainwater tank and the water storage tank runs at least partially through the downpipe.

In this way the rainwater, when available, is converted to potable water and transferred to the water storage tank of the house and thus to all water-consuming devices within IE1 2 0 0 28 -3the house. This reduces the use of mains water, which may result in cost-savings for the house-owner. The routing of the fluid communication path between the downpipe to is a particularly efficient manner of providing a support mechanism for the fluid path, typically a pipe or hose, between the rainwater tank and the water storage tank.

In one embodiment of the invention there is provided a rainwater harvesting system in which the fluid communication between the rainwater tank and the water storage comprises a pipe that runs at least partially though the downpipe. In this way, the pipe to transfer water from the rainwater tank to the water storage tank is supported by the 10 existing plumbing infrastructure of the house. This reduces the cost and complexity of the installation of the rainwater harvesting system of the invention. Additionally, the system may be easily retro-fitted to the standard plumbing of a house.

According to the invention there is provided a rainwater harvesting system for a house, 15 the house having a plurality of downpipes and a water storage tank connected to the mains water supply via a mains water valve, the rainwater harvesting system comprising at least one above-ground rainwater tank comprising a rainwater level sensor, the rainwater tank being in fluid communication with the water storage tank; a water purification unit; a pump adapted to draw water from the at least one rainwater tank to 20 the water storage tank through the water purification unit; means to close the mains water valve when rainwater is available in the at least one rainwater tank characterised in that the rainwater harvesting system comprises a rainwater tank for each of a subset of two or more of the plurality of downpipes, each rainwater tank being fitted to, and in fluid communication with, one downpipe; and a single pump in fluid communication 25 with each rainwater tank byway of a manifold having a plurality of inlets and a single outlet.

In this way, a small above-ground rainwater tank may be connected to each of a number of downpipes, providing a substantial combined volume for rainwater storage without the 30 need to source and install a large underground water storage tank. Furthermore, the use of a single pump greatly reduces the costs involved. The tanks are dumb tanks and do not contain a pump. The pump draws water from any of the rainwater tanks having rainwater therein, via the manifold.

IE1 2 0 0 28 -4In another embodiment of the invention there is provided a rainwater harvesting system further comprising a rainwater tank fitted to, and in fluid communication with, every downpipe. In this way, the maximum amount of rainwater have be harvested and stored, without the large cost and disruption of the installation of an underground tank In a further embodiment of the invention there is provided a rainwater harvesting system in which the fluid communication between a rainwater tank and the water storage tank runs at least partially through the downpipe to which the rainwater tank is fitted. This provides a convenient way to support the fluid communication pathway, minimising the cost and disruption of installing the rainwater harvesting system.

In an alternative embodiment of the invention there is provided a rainwater harvesting system in which the fluid communication between a rainwater tank and the water storage comprises a pipe that runs at least partially though the downpipe to which the rainwater tank is fitted, in this way, the pipe to transfer water from the rainwater tank to the water storage tank is supported by the existing plumbing infrastructure of the house. This reduces the cost and complexity of the installation of the rainwater harvesting system of the invention. Additionally, the system may be easily retro-fitted to the standard plumbing of a house.

In another embodiment of the invention there is provided a rainwater harvesting system in which the manifold comprises remote controlled valves on the inputs. In this way, the manifold can be used to control which rainwater tanks the pump will draw water from.

In one embodiment of the invention there is provided a rainwater harvesting system further comprising a control unit in communication with the rainwater level sensor and the means to close the mains water valve. In this way, the availability of water in the rainwater tank may be monitored and the operations of the rainwater harvesting system controlled accordingly. Furthermore, the system can switch back to mains water supply if the supply of rainwater is insufficient.

In an alternative embodiment of the invention there is provided a rainwater harvesting system in which the the above-ground rainwater tank has a footprint of approximately 0.225 m2 or less.

|E1 2 0 0 28 -5Detailed Description of the Invention The invention will now be more clearly understood from the following description of an embodiment thereof given by way of example only with reference to the accompanying drawings in which:Fig. 1 is a diagrammatic representation of the rainwater harvesting system according to the invention installed in a house; Fig. 2 is a detail of the area marked detail 01 in Fig. 1; Fig. 3 is a detail of the area marked detail 02 in Fig. 1; Fig. 4 is a detail of the area marked detail 03 in Fig, 1; Fig. 5 is a block diagram showing the path of water in the rainwater harvesting system of the invention; Fig .6 is a block diagram of the main module of the rainwater harvesting system of the invention; and Fig. 7 is a flow chart indicating the manner in which the system operates.

Referring to the drawings, and initially to Figs. 1 and 2 thereof, there is shown a rainwater harvesting system indicated generally by the reference numeral 100, the rainwater harvesting system 100 being installed in a house 500, the house 500 having a water storage tank 102 connected to the mains water supply 104 via a mains water valve 106, in this case operated by a standard float assembly 107. The house 500 further comprises a pair of downpipes 108, 109 wherein each downpipe 108, 109 is in fluid communication with a rainwater tank 110, 111, the rainwater tanks 110, 111 also being in fiuid communication with the water storage tank 102 in the house 500 by way of a pump such that the pump can draw water from the rainwater tanks 110,111 to the water storage tank 102 through a water purification unit, the rainwater harvesting system 100 IE1 2 0 0 2 8 -6further comprising means to close the mains water valve 106 when rainwater is available in the rainwater tanks 111.

The rainwater tanks 110, 111 are connected to the pump by way of a manifold (not shown) having a plurality of inlets (not shown) and a single outlet (not shown). The inlets are fitted with solenoid controlled valves (not shown) to control whether the inlet is open or closed.

The rainwater harvesting system 100 comprises a main module, indicated generally by the reference numeral 112. The main module 112 comprises the control components, including processing requirements, for operation of the rainwater harvesting system 1OO. The main module 112 comprises a Power Supply Unit (PSU) A for providing suitable power to the other elements of the main module; the pump B for bringing water from the rainwater tanks 110, 111 to the water storage tank 102; the water purification unit C for rendering the rainwater from the rainwater tanks 110, 111 potable and; a control unit D, including a valve controller (not shown) which provides means to close the mains water valve 106 as required. The valve controller operates on the float assembly 107, holding the float assembly 107 up, thereby closing the mains water valve 106, when rainwater is available in one or more of the rainwater tanks 110,111 so as to prevent supply of water from the mains water supply. The valve controller releases the float assembly 107 when there is no rainwater available, and thus allowing the float assembly 107, mains water valve 106 and mains water supply to operate as if the rainwater harvesting system 100 was not present. The position of the valve controller is controlled by a low level float switch 120 which measures the water level in the water storage tank 102. When the water level drops below a certain level, the release of the float assembly 107 is triggered so as to allow the system to return to normal operation with the mains water supply. This provides a back-up feature to prevent demand for water from the water storage tank 102 outstripping that which can be supplied by the pump B. The valve controller is implemented using an electro-magnetic switch.

The main module 112 is mounted over the water storage tank 102, by way of mounting brackets 114. The brackets 114 ensure that the main module 112 remains in place with respect to the water storage tank 102. The main module comprises a rainwater inlet 116, which receives the rainwater under the action of the pump B, and supplies it to the water IE 1 2 0 0 2 8 -7purification unit C. The purified water then enters the water storage tank 102 through a purified water outlet 118 of the main module 112. The water purification unit G comprises a filtration assembly, having a 25 pm (micron) filter followed by a 1 pm (micron) filter; and a UV sterilization apparatus (not shown).

The main module 112 further comprises a high level float switch 122 which controls the operation of the pump B. While the float assembly 107 is held in the off position by the valve controller, the pump B operates until the high level float switch 122 detects the maximum permitted water level in the water storage tank 102. If the high level float switch 122 subsequently detects that the water level in the water storage tank has dropped, it will cause the pump B to operate once more until the maximum water level is reached. In practice, the pump will operate once the water level has dropped approximately 10cm below the high water level. This prevents excessive cycling of the pump. The high water line in the water storage tank 102 will drop 10 cm before the pump operates to draw more rainwater into the water storage tank 102.

The water storage tank further comprises an overflow pipe 124 to allow water above the maximum water level to safely drain away from the water storage tank so that the water storage tank does not overflow.

The rainwater inlet 116 of the main module 112 is connected to the manifold (not shown) to which are connected a pair of pipes 126, 127 that provide a fluid path between the rainwater tanks 110, 111 and the main module 112. The pipes 126, 127 travel from the rainwater tanks 110, 111 to the eave-area of the house 500 though the downpipes 108, 109.

Referring now to Fig. 3, in which like parts have been given the same reference numerals as before, the path of one of the pipes 126 is shown. The pipe 126 travels up the downpipe 108, and is thus indirectly secured to the outside wall 502 of the house 500 and suitably supported, without the need for additional supporting infrastructure. The pipe 126 enters the attic (the standard location of a domestic water storage tank) above the gutter 128 and below the eave 130 of the house 500. The path of the other pipe 127 is similar, but through a different downpipe.

IE1 2 0 0 28 -8Referring now to Fig. 4, in which like parts have been given the same reference numerals as before, there is shown the rainwater tank 110 and the downpipe 108. The rainwater tank 110 comprises a combined water inlet and outlet 132 in the side thereof, near the base, adjacent the downpipe 108 and the wall 502 of the house 500. The combined water inlet and outlet 132 is connected to a standard downpipe diverter 134. The downpipe diverter 134 comprises a pipe having one end in fluid communication with the rainwater tank 110 and an opposite end in fluid communication with the downpipe 108. Such a component is readily available off the shelf, and will in general comprise a coarse filter (not shown), for the removal of leaves and other similar debris from the rainwater before it reaches the rainwater tanks 110, 111. Typically this coarse filter (not shown) has a mesh size of 1mm.

The rainwater tank 110 comprises a float 136 that floats on the water therein. The float 136 supports a rainwater level sensor 138 for indicating if there is water present in the rainwater tank 110. The float 136 further supports the termination 140 of the pipe 127 for supplying water to the main module 112. This termination is fitted with a further filter (not shown) having a mesh size of 0.5 mm. Rain water is sucked from the rainwater tank 110 by the pump B in the main module 112 through the pipe 127. The float 136 supports the termination 140 of the pipe 127 approximately 100 mm below the surface of the water so as to avoid articles that may be floating thereon.

Data from the rainwater level sensors 138 may be transmitted to the main module either by wired or wireless communication. If wired communication is used, the pipes 126,127 may comprise a double bore hose, wherein one bore is used for rainwater and the second bore is used for a wired communications link between the rainwater level sensor and the main module. In such cases the wired communications link may join the pipe 126, 127 at the floats 136.

The rainwater tanks are formed from PVC, but it will be understood by the person skilled in the art that other materials such as polyurethane or the like may be used. Specially designed narrow profile tanks are used to reduce their visual impact. Each tank is selected from a range of sizes to suit the quantity of rainwater that will be directed thereto by its associated downpipe. It will be understood by the person skilled in the art that some downpipes, depending on the design of a house, their location on the house IE 1 2 0 0 2 8 and their diameter will deliver more rainwater than others for a set level of rainfall. In this way, the size of each rainwater tank may be chosen to as to optimise the trade-off between storage capacity versus visual impact and convenience of installation. For example, for a typical semi-detached two-storey house of 45 m2 with two downpipes, a suitable installation would involve an approximately 560 litre tank of dimensions approx 300 mm x 750 mm x 2500 mm at each downpipe.

The preferred tanks for use with the invention are an approximately 450 litre tank having dimensions of 300mm x 600mm x 2500mm; an approximately 560 litre tank of dimensions 300 mm x 750 mm x 2500 mm; an approximately 720 litre tank of dimensions 300 mm x 600 mm x 4000 mm; and an approximately 900 litre tank having dimensions of 300mm x 750mm x 4000mm. Each of these tanks provide a relatively small, unobtrusive footprint, that further allows ease of handling and installation. All dimensions in relation to the tank are approximate.

Referring now to Fig. 5, in which like parts have been given the same reference numerals as before, there is shown a block diagram of the path taken by rainwater harvested by the system of the invention. In step 500, the rainwater is passes through the coarse filter (not shown) in the downpipe diverter 134 on its way to the rainwater tank 110 and in step 502 the rainwater is collected in the rainwater tank 110. In step 504, the rainwater passes though the termination 140 on the end of the pipe 126, 127 and from there passes through the manifold (not shown). In step 506, the water passed from the manifold to the pump B in the main module 112 on its way to be purified.

In step 508, the rainwater passes through a filtration assembly (not shown) to remove particulates greater than 1pm. In step 510, the water is sterilised by a UV light sterilisation apparatus, rendering safe any organic pathogens therein. It is important that the flow rate of the rainwater through the UV light sterilisation apparatus does not exceed that required for safe operation thereof. The UV light sterilisation apparatus operates off a 220VAC power supply, and must have a separate circuit breaker to protect the 12 V DC power supply used to power the other components of the system of the invention. The UV light sterilisation apparatus (not shown) may comprise an alarm to indicate when the buib (not shown) is blown. The alarm may be visual or audio and may comprise communication means to transmit an alarm message to a user or manager of IB1 2 0 0 2 8 -10the particular installation of the rainwater harvesting system. If the bulb alarm is triggered, the system may be configured to immediately switch off the pump and open the mains water valve 106 so as allow the house 500 to revert to mains water supply and avoid contamination of the household plumbing with non-sterilised water.

Finally, in step 512 the rainwater passes to be stored in the main water storage tank 102 of the house 500. The rain water is now clean, sterile and odourless.

Referring now to Fig. 6, in which like parts have been given the same reference numerals as before, there is shown a diagrammatic representation of the control unit D and the modules in communication therewith. The control unit D receives information from the low level float switch 120, high level float switch 122, rainwater level sensors 138 and a pump sensor 600 that provides information on whether the pump B is operating. Based on the information received, the control unit controls the pump B; the valve controller 602 for controlling the mains water valve 106; and valves on the manifold inlets, based on the rainwater level sensors 138 for the rainwater tanks connected to the inlets.

Referring now to Fig. 7, there is shown a flow chart indicating the operation of the rainwater harvesting system of the invention. If, at 700, the rainwater harvesting system detects that there is insufficient water present in a rainwater tank 110, 111 then the manifold valve for that tank is shut. If at 702, the system detects that there is no rainwater available in any of the tanks, the system opens the mains water valve and ensure that that the pump is turned off. All manifold inlet valves will be shut at this time. If, at 704, the systems detects that there is some failure within the system, the mains water valve is opened and the pump is turned off. If, at 700, the rainwater harvesting system 100 detects that there is water present in at least one of the rainwater tanks 110, 111 the system 100 will operate to open the valves on the manifold inlets for the tanks containing rainwater and close the main water valve 106. In this way, the water supply tank 102 is now being supplied by the rainwater harvesting system 100 only. Once the mains water valve 106 has been closed, supply of water to the water supply tank 102 is controlled by the pump B bringing water from the rainwater tanks 110,111. Operation of the pump B is controlled by the high water level switch, at 706, in the water supply tank 102. Once the water level in the water supply tank 102 drops below the maximum water IE 1 2 0 0 2 8 -11level for the water supply tank, the high water level switch 122 triggers the pump B. When the water level reaches the maximum water level again, the pump B is turned off. If, at 708, the water level in the water supply tank 102 drops too low, the system opens the mains water valve 106 as the rainwater system is not meeting demand. In this way, water will be supplied to the water supply tank from the rainwater tanks 110, 111 and from the mains.

In another embodiment of the invention, the main module 112 may be fitted beside the water supply tank in the attic of the house. This would allow for the system to be installed in locations where there might not be sufficient height to install the main module 112 above the water supply tank, or where the rafters may not be strong enough to bear the weight of the water storage tank 102 and the main module 112. In such installations, the valve control unit, high level float switch and low level float switch will be supported above the water supply tank by the mounting brackets.

It will be apparent to the person skilled in the art that the water purification unit may implement one or more of a number of known water purification methodologies, and may include further purification steps, for example a carbon filter.

In the specification the terms 'comprise’, 'comprises', ‘comprised’ and ‘comprising’ or any variation thereof and the terms ‘include’, 'includes1, ‘included’ or ‘including’ or any variation thereof are considered to be totally interchangeable and they should ail be afforded the widest possible interpretation.

The invention is not limited to the embodiment herein described, but may be varied in both construction and detail within the terms of the claims.

Claims

1. A rainwater harvesting system for a house, the house having a downpipe and a water storage tank connected to the mains water supply via a mains water valve, the rainwater harvesting system comprising an above-ground rainwater tank in fluid communication with the downpipe, the rainwater tank also being in fluid communication with the water storage tank and comprising a rainwater level sensor; a water purification unit; a pump adapted to draw water from the rainwater tank to the water storage tank through the water purification unit; means to close the mains water valve when rainwater is available in the rainwater tank characterised in that the fluid communication between the rainwater tank and the water storage tank runs at least partially through the downpipe.

2. A rainwater harvesting system as claimed in claim 1 in which the fluid communication between the rainwater tank and the water storage comprises a pipe that runs at least partially though the downpipe.

3. A rainwater harvesting system for a house, the house having a plurality of downpipes and a water storage tank connected to the mains water supply via a mains water valve, the rainwater harvesting system comprising at least one above-ground rainwater tank comprising a rainwater level sensor, the rainwater tank being in fluid communication with the water storage tank; a water purification unit; a pump adapted to draw water from the at least one rainwater tank to the water storage tank through the water purification unit; means to close the mains water valve when rainwater is available in the at least one rainwater tank characterised in that the rainwater harvesting system comprises -13IE 1 2 Ο Ο 2 8 a rainwater tank for each of a subset of two or more of the plurality of downpipes, each rainwater tank being fitted to, and in fluid communication with, one downpipe; and 5 a single pump in fluid communication with each rainwater tank by way of a manifold having a plurality of inlets and a single outlet.

4. A rainwater harvesting system as claimed in any of claims 3 in which the fluid communication between a rainwater tank and the water storage comprises a pipe 10 that runs at least partially though the downpipe to which the rainwater tank is fitted.

5. A rainwater harvesting system as claimed in any preceding claim further comprising a control unit in communication with the rainwater level sensor and the means to close the mains water valve.