Hybrid hot water.pdf (1.0 MB)
Hi, I live in South Carolina, USA.

Let me describe my situation. I am looking for a recommendation for a system that will work for me.

I have a 6KW grid-tied solar system.

The system is net metered. Unfortunately, the utility credits me $0.03 for the excess power I sell to them. They charge me $0.12 for the power I get from them. So it is in my interest to use as much of the power I generate as is practical.

My home has a 400 amp service. Unfortunately, the wires carrying the 400 amp main feed are not accessible. The mains are split into 2- 200 amp panels that are accessible. The inverter for the solar panels is in close proximity to the mains panels. Also, my WiFi signal is good in this area.

To improve energy efficiency I installed a hybrid hot water heater. For now, I plan to use this hot water heater as my main energy storage system. I need to put together a system that will activate the HW heater when there is excess solar power available. This would mostly be times when the A/C or heat pump is not running. The hot water heater has the ability to run at a higher temperature when it is given a signal to do so. I will attach info from the manufacturer to make this clear.

I also have a Spa that is heated by a resistance heater. There is WiFi available near the spa so I could also use this as energy storage. That heater could be controlled with a triac as you do with water heaters.

I have some knowledge of programming and electronics. Also, I belong to a local maker space where I can get help with this.

I would like to make this as simple a project as possible. I am hoping you can recommend an existing system that I could purchase and adapt to my situation.

Thank You, Ray

Take a look at mk2pvrouter.co.uk and contact Robin. If he doesn’t respond quickly, don’t despair, because I know he’s preoccupied as there is a serious illness in the family.

There’s background information and more about Robin’s diverter/router in ‘Learn’.

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