System to flush toilets with waste water from AC units

Enabling waste condensate from air conditioning units to be stored and recycled as flushing water for toilets to reduce water footprints.  
Resource Use

Problem addressed

Billions of litres of condensate water from air conditioning units are drained to waste every year, and this is only going to increase as demand for air conditioning rises as a result of the climate crisis. Alongside this, many places are becoming more water stressed, yet clean and expensive mains water is often used to flush toilets.  

Solution overview

Encore Cistern enables condensate from air conditioning units to be stored and recycled as flushing water for toilets. The cistern works exactly like a traditional cistern with the exception that it has an extra filling connection to allow a separate water source to be introduced (from the air conditioning unit). The Encore can hold 18 litres of water; three times more than traditional cisterns. Despite this the Cistern has no additional spatial requirements, it is designed to fit in standard service voids. The Encore has a dual-chamber design. When the air conditioning system is in use, both chambers are filled with condensate, and when the toilet is flushed, the lower chamber is replenished by the upper chamber, to ensure a quick refill. If there are multiple flushes in a short period of time, the Encore cistern is filled the conventional way.  

The Encore cistern can be used in all concealed toilet installations, both new and existing, and is the first and only cistern to give BREEAM credits and LEED points. In addition the materials in the cistern are fully recyclable.  

Company name

Encore Cistern

UK availability

Yes

Date added

Jul, 2023

Links

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Case study

Encore installed their cisterns in Warrington with a global facilities management company to demonstrate that condensate does play a major role in sustainability, even here in the UK. Recovering condensate waste that is normally sent to drain will not only save users money, it will also help achieve water conservation goals, saving billions of litres of water each year. 

Installing Encore’s cisterns and metering the mains water gave an overall usage of each toilet. Data obtained from June 2018 – November 2019 clearly highlights the Encore’s water-saving abilities. 

The traditional toilet used 85,882 litres, whilst the Encore cistern 1 used 11,753 litres and Encore cistern 2 used 26,481 litres.  

Combined consumptions of the two Encore cisterns, and taking the average showed an incredible water saving of 66,765 litres and an impressive £212.98 based on water rates including waste @£3.19m³  

Annual savings based on the figures above using the traditional cistern and Encore cistern 2, would show a ROI in 15 months based on the cost of a single unit being £160.00. 

Facts and Figures

12-36

Months return on investment

and there is a reduced requirement of expensive mains water.

£160

Cost of single unit

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