How the Mixergy tank helps you to harness free solar energy to help decarbonise and save money on bills
At Mixergy we are focused on supporting households to transition from fossil fuel heating to low and zero carbon alternatives, whilst also helping to reduce energy bills. One of the ways that we do this is by connecting a solar photovoltaic (PV) array to the tank, enabling Mixergy homes to use the spare electricity generated from the sun to heat their hot water, rather than being lost to the grid. In this way, the Mixergy tank acts like a lithium-ion battery solution, but 4-5 times less expensive.
How it works
Using thermal stratification, Mixergy tanks heat from the top down which means faster heating and lower heat losses. Mixergy tanks only heat the hot water you need – actually this is typically just 40% of the tank volume – energy and money are saved every time a full tank is not heated. By using this volumetric heating approach and a unique smart sensor arrangement to constantly monitor the state of charge, the tank creates the headroom to optimise the consumption of free solar energy from a solar PV system.
A conventional hot water tank will typically heat to 100% using grid imported energy (gas or electric) first thing in the morning. As a result, even after you have your morning showers, there is a limited amount of headroom in the tank available for surplus solar energy that you generate throughout the day.
The Mixergy Tank on the other hand, can be automatically programmed to optimise the use of solar energy by leaving maximum capacity available to be heated for free by the sun during the day.
In this example, the tank heats just what you need using your boiler, heat pump or by direct electric to get through the early morning demand for showers. The vast majority of the tank is left available to be heated by surplus solar energy throughout the day. And because of the top-down volumetric heating and tracking of the tank’s state of charge, the primary heating source can always intervene to make sure you don’t run out of hot water.
Reducing import of grid energy by more than 35%
Through BEIS and Innovate UK funded trials, we have been able to demonstrate that a Mixergy tank and solar PV system can reduce the import of grid energy (gas or electric) by more than 35%.
The reduction in grid energy depends on the size of the PV array, its orientation and the capacity (size) of the tank. As shown in the graph below, a typical 4kWp PV system installed alongside a 210 litre Mixergy tank gives a reduction in grid export of more than 35%. This increases to almost 40% with a 300 litre tank.
Installation of a Mixergy tank is broadly the same as with a conventional cylinder and requires no specialist training. All Mixergy cylinders are also ‘Heat Pump Ready’: this means they can be connected to a heat pump using a plate heat exchanger should you ever decide to switch to a heat pump.
Key benefits of the Mixergy tank include:
- Maximise the self-consumption of your solar energy whilst reducing the import of grid energy by as much as 35%.
- Giving you the ability to monitor and control hot water through the Mixergy App and gauge.
- Operating a smart ‘IoT’ device that can be connected to other platforms such as Amazon Alexa and Google Home voice control systems.
- Taking advantage of dynamic time-of-use electricity tariffs to provide low-cost hot water in off-peak periods.
- Heating just the hot water you need (typically around 40% of a tank’s capacity) ensuring faster reheat times!
- Reduce your energy wastage by lowering heat losses; store less water and optimise your schedule using machine learning.
- Reduce gas consumption and prevent boiler short cycling. EST Verified.
- Providing a more accessible and affordable energy storage solution than a lithium-ion battery storage.
To find out more about Mixergy and our solar tank, please get in touch.