GB2374658A

GB2374658A - Waste water heat recovery system

Info

Publication number: GB2374658A
Application number: GB0109376A
Authority: GB
Inventors: Edmund Peter Gortowski
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-04-17
Filing date: 2001-04-17
Publication date: 2002-10-23
Also published as: GB0109376D0

Abstract

A waste water heat recovery system comprises an insulated tank 1, in the incoming cold water supply side of a hot water system, which recovers and stores heat from the outgoing warm water stream 2 such as bath or washing water by means of a heat exchanger 3 located in the insulated tank 1. The insulated tank 1 may be insulated using foam or clad lagging. The insulated tank 1 may supply pre-warmed water to a main hot water tank 8 via a connection pipe 7. The main hot water tank 8 may then be heated to the required temperature by conventional means such as an electrical immersion heater or a hot water coil. The warm water stream 2 may be supplied by connections 2A, 2B, 2C, 2D.

Description

WASTE WATER HEAT RECOVERY SYSTEM This invention relates to a simple and cost-effective means of recovering heat energy from warm (or hot) water waste in domestic or other buildings.

The costs of excess or wasted energy useage are well known-they are both financial, and damaging to the environment. Every hour of every day a lot of waste warm or hot water literally goes"down the plughole"and is lost to the wider environment-from sinks, showers, baths, and so forth. To recover some of this heat would mean a reduction in the overall energy consumption, and so aid both the economy, and the environment Some heat recovery systems are in use already, but these tend to be large, and/or expensive/complex.

According to the present invention there is provided a system of recovering some of this otherwise waste water heat in a relatively simple and cost-effective manner, by the provision of a heat exchanger which takes heat from the outgoing warm waste water to pre-heat the incoming feed to the hot water system. Therefore, less heat energy will be required to raise the new water up to the required temperature in the hot water system. It is an objective of this invention to contribute to the conservation of energy, and the reduction of damaging environmental impacts arising from the use of conventional power sources A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing (which is not to exact scale) in which :- Figure 1 shows a cross sectional diagram of the heat exchanger Figure 2 illustrates a schematic diagram of the connected system.

Referring to Figure 1, the basic unit consists of a tank 1, to contain the incoming water which is to be heated by the warm waste water outlet stream 2. This stream 2, passes through a heat exchanger 3 within the tank, which may be a coil, finned plate, or any other form of heat exchanger. The waste water then exits to the conventional drainage system from the tank and exchanger outlet 4.

Supply water enters the tank 1, cold and under supply pressure, and exits to the conventional hot water system via outlet 6, pre-warmed from contact with the warm waste heat exchanger. There is a holding space 1 A within tank 1 to retain the heated water, As the outflow of warm waste need not coincide with the system taking in water for heating. These flows will occur more or less together for some things, such as a shower, but will be displaced in time for such things as a bath, where the bath water outlet will create water pre-heating for the next demand inflow to the system.

As there will be a need to store the recovered heat (in the form of pre-warmed water), then the tank 1 will need to be well insulated, and this can be achieved by any of a variety of well known means, such as foam or clad lagging.

The overall system arrangements are as shown in Figure 2, where the tank 1 containing the heat exchanger 3, supplies the pre-warmed water to the main hot water tank 8 via a connection pipe 7, which should also be insulated to retain heat. The main hot water tank 8 may then be heated to the required temperature by conventional means such as electrical immersion heater, hot water coil, or similar, and supplies the hot water system via the feed pipe 9.

The warmed waste supply connections are as designated 2A, 2B, 2C, 2D, and so forth, and these combine to form the input to the tank 1, at connection 2. These sources would include such things as baths, showers, sinks, washing machines, and so forth, being any suitable source of heated waste water. The heat exchanger 3 isolates the waste water from the fresh supply, so there is no risk of contaminating the fresh water.

As shown, the system is a gravity drain, which would be a conventional and convenient way to arrange this system, but it could also be envisaged that the warm waste be pumped to the heat exchanger tank where the physical layout precludes a gravity drain. It is envisaged that the preferred method would be gravity drainage where feasible, as this is both simpler, and does not then consume any additional energy.

The size and detailed arrangements of the system can be varied to suit different applications, such as larger or smaller premises, an example being the differences between a small house and a large hotel.

Claims

CLAIMS 1. A simple system to recover heat from warm waste water, by using this waste to preheat the incoming supply water for the hot water system, by means of an insulated tank and heat exchanger arrangement in the incoming water supply system.