Waste Water Heat Recovery for Showers

Recoup Drain+ installation at Gymbox Farringdon has paid for itself in just over a year & is now reducing facility costs

Sep 14, 2018 | Case Study

Nineteen Recoup Drain+ waste water heat recovery (WWHRS) units installed at Gymbox Farringdon have recouped enough energy and reduced costs so that they have effectively paid for themselves. The saving continues and the facility benefits from significantly reduced operational costs due to the incorporation of the waste water heat recovery systems.

Gymbox in Farringdon London opened in 2016, it is a gym with a big difference, designed to stand out from others. Not only do they have the industrial style and less-conventional gym feel that is associated with the Gymbox brand, they also provide all their members and visitors with a highly efficient and energy saving shower. Using the Recoup WWHRS Drain+ waste water heat recovery system every shower recovers waste water heat energy to preheat incoming cold water and reduce the heating requirement for the buildings water heater, saving energy.

As the showering facilities in the Gymbox building are in the basement, from the beginning of the project the plans required some outside of the box thinking. Woodward & Co (Environmental) Ltd specialise in the design & installation of building services predominately within the retail & leisure sectors. They embrace new changes to HVAC principles and practices including associated plant and equipment to ensure they remain at the forefront of the industry and keep up to date with legislation changes. This ethos and approach brought Recoup Energy Solutions and the range of innovative waste water heat recovery systems to their attention.

The project planners with Woodwards directing the M&E for the building wanted to ensure that an energy efficient and sustainable approach was taken for the buildings services. Woodwards worked with the Recoup WWHRS team to implement the waste water heat recovery systems in a way that maximised recovery for the number of showers being incorporated. Also using an appropriate number of units for the facility and the investment required.

The Recoup Drain+ was selected as it provides a solution that is easily incorporated into the wet room shower areas with flush integration to floor levels. Heat carrying waste water from the shower runs into the slot of the stainless-steel drain cover and over copper exchangers transferring the heat to incoming mains cold water. The energy transfer creates pre-heated water which can then be fed back to the shower and/or the water heater for the building.

The Drain+ is a horizontal waste water heat recovery system that achieves impressive efficiencies of up to 50% and recovering more than 12.5 kWh of energy depending upon flow rate and installation method. It has a patented heat exchanger and incorporates a built-in water trap that is easily accessible for cleaning.

Across the male and female changing facilities a total of nineteen Recoup Drain+ systems have been installed servicing a total of thirty-nine shower cubicles with two showers per unit each. The Drain+ units at Gymbox Farringdon are all installed using the System B installation method. The pre-heated water produced by the waste water heat recovery system is sent back to the mains cold water side of each thermostatic mixer for the two showers supplying the unit. As the temperature of the pre-heated water increases during the use of the shower the amount of hot water required to keep a constant temperature reduces. This in turn decreases the demand of hot water from the water heater and therefore the energy that would have been used to create it.

Recoup Drain+ savings calculator for Gymbox Farringdon

Based on usage data provided to Recoup Energy Solutions prior to installation the average shower usage would be 23.82 time every day, with 5.5 litre/min of water from each shower running for a duration of 5.25minutes per shower. These figures were put into the Recoup savings calculator combined with the Drain+ efficiency values. The calculations showed saving predictions of £11,010.75 per annum meaning the investment into all Recoup Drain+ units installed would be returned within 1.1 years. In addition, this energy reduction in turn reduces CO2 production by 43,000Kg per annum and along with reduced load on the facilities water heaters installed.

Now over eighteen months after Gymbox Farringdon has opened the facility will be spending over £11k less per year on their operational costs. As the Recoup Drain+ units require minimal maintenance, no more than any other shower, the savings will continue year upon year.

All calculations and figures used were correct at the time of calculation using values taken from the Energy Saving Trust Websites. Content also used from Gymbox and Woodward & Co (Environmental) websites. For more information on Gymbox or Woodward & Co (Environmental) Ltd visit their websites.

For more information on Recoup Energy Solutions and the Drain+ contact us.

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