Water Energy Recovery

What is Water Energy Recovery?

In an average house up to 90% of the hot water is used for showering. Most of that heat goes straight down the drain with the waste or grey water. A water energy recovery system can reclaim up to 60% of the heat that would normally be lost down the drain when you shower. That means that the cost of a shower both financially and in carbon emissions is only 40% of what it would be without the Water Energy Recovery System installed.

How Does it Work?

There are different types of rainwater harvesting systems, but the principle on which they operate is similar. All Green Energy Doctor whole house systems consist of two main components:

Shower Tray
The air is extracted from specific rooms (specifically, kitchens, bathrooms and cloakrooms) using an efficient fan that is housed in the centrally mounted unit. As the air passes through the unit, the heat is transferred to incoming outside fresh air that has been filtered to prevent the ingress of airborne pollutants such as pollen and dust. The system works by enabling the two air streams (in and out) to move close to one another without actually mixing. In this way, one air stream warms the other. This is done inside a counter- flow heat exchanger, which is made up of hundreds of individual air channels.

Heat Exchanger
The main unit is connected to each room via a number of flexible or rigid ducting tubes that allow air to be drawn from and delivered to the specific rooms. These ducts can be hidden within internal walls and ceilings of the property. This is a very simple process for new build or existing properties of one floor, but may take a little more work for existing properties with more than one level.

Is It Suitable For My Requirements?

Which system is most suitable for your property or project depends on a number of factors that Green Energy Doctor will take into account as part of the design. However, the following are some general principles that will help you decide whether it is a technology you would like to consider in more detail for your property or project:

Positioning & Location
In our experience, only a small percentage of sites are suitable for wind turbines to gain the benefit required to make them economical. It is critical in siting a wind turbine that it is well clear of large obstacles, especially in the path of the prevailing wind. There has to be a good line of sight from the turbine. If the turbine is too near to large obstacles such as buildings, trees or hills the true potential of the system will be difficult to attain. As a general rule:

• If the turbine has to be placed behind an obstruction, it should be ten times the height of said obstruction.
• If the mast is to be placed in front of a building, to avoid any turbulence, it should be twice the height.
• They are of limited effectiveness in built up urban areas

Water Requirements
One disadvantage is that wind power is an intermittent power source. The production from a wind turbine may increase or decrease dramatically over a short period of time with little or no warning. Therefore, turbines are used, generally, to supplement other sources of power as from solar panels or the National Grid.

What Are The Benefits?

Save money
The low initial cost results in a very quick payback relative to other technologies. The Water Energy Recovery System will pay for itself many times over during it's long life. Average annual savings are equivalent to a solar water heating system but at a fraction of the cost.

Reduce your carbon foot print
Water Energy Recovery System will save between 300kg and 1000kg of carbon dioxide emissions per year, depending on how much you shower and what fuel you heat your water with.

Meet environmental targets
The Water Energy Recovery System has proved so popular in Holland where it was developed, as a very cost effective way to meet environmental targets, that it is now installed in 20% of new houses.

Reliability
Simple, low maintenance design with no moving parts. Copper construction means the system should last for many years.

Performance
Official test figures show that the Shower Save can recover over 60% of the energy when you shower.

Other benefits
Reduces the re-heat time of hot water cylinders as the fresh water entering the cylinder has already been pre-heated. If used in conjunction with a solar water heating system you should be able to get the majority of your hot water from solar.

Applicability
Will work just as well with showers over baths, but not with with baths when filling and emptying are not simultaneous.

How Much Does It Cost?

The cost of a Green Energy Doctor water energy recovery system will depend on the the complexity of the installation. Typically, a system for a family home costs less than £1,200.

Once a technical survey has been carried out, all Green Energy Doctor prices will be given as fixed prices.