Good morning - this is my first post.

I have an Alliance Heat Pump connected to a Kwikot 150 Litre solar geyser which has an Isotherm blanket.

Is it possible to connect a solar panel to the same geyser using non-return valves. The heat pump will supplement the heating when the solar is unavailable. The control of the heat pump and solar circulation pump will be managed by an Arduino controller.

Do you want to connect the heat pump to the hot water out and cold water inlet of the geyser or does it have more connection points or maybe use one of those double inlet connections (can't remember the name)?

I presume you would want the solar to work in the heat of the day and then late afternoon the heat pump must bump up the temp if not hot enough and then not heat at night time so you have coldish water in the morning for the solar to do its thing?

The attached image reflects the current geyser water connection configuration. I would like to connect the inlet of the solar panel to “C” on the geyser and the outlet of the solar panel to “B” on the geyser - both with the applicable fittings and valves if this is possible.

You are correct regarding the required operation of the heat pump in the late afternoon if the water temp is too low. However the heat pump will also be used in the early morning to raise the water temp, if required, for showering.

Thanks Vassen. Will non-return valves be necessary for each system?

You will need 2 non return valves, I would put them on the 'C' pipe. Both systems will be pumped so without non-return valves you will be pulling water around the non running circuit in reverse.

Also, when you plumb in your system, make sure the solar circuit pipework on the 'B' leg has a loop BELOW the storage tank to avoid thermal syphoning.

If you want a design for an ESP8266 based unit then I have one I built, it has a web interface to monitor it and has an automatic defrost mode (if you have low temperatures around freezing). It also tries to extract maximum heat from the panel by controlling the on/off cycle of the pump when the delta temperature is low.

It just needs 2 x 10K NTC thermistors, a PCF8591 module, a solid state relay, an ESP8266 module such as a Wemos D1 and some form of power supply.

Optionally you can add an I2C 2 x 16 line LCD module.

Edited June 9, 20215 yr by Acuario

Thanks for your feedback Acuario. Are you able to share the circuit configuration and code of your solution?

On 2021/06/07 at 2:37 PM, Graeme McK said:

You are correct regarding the required operation of the heat pump in the late afternoon if the water temp is too low. However the heat pump will also be used in the early morning to raise the water temp, if required, for showering.

If you use the heat pump in the morning and don't use most of the hot water then you don't leave much for solar panels to do. 

Maybe going to get overheating of the hot water?

Here is the very basic schematic. It uses a Wemos D1 Mini and YL-40 PCF8591 module. 2 x 10K NTC thermistors and a solid state relay.

I'll upload the code later.Schematic1.pdf

..here is my code. Use it as a basis for your controller or as an example.

I use the same code for 2 different controllers, hence the multiple html files.

SolarWaterController.zip

On 2021/06/30 at 9:02 AM, Acuario said:

Here is the very basic schematic. It uses a Wemos D1 Mini and YL-40 PCF8591 module. 2 x 10K NTC thermistors and a solid state relay.

I'll upload the code later.Schematic1.pdf

Thanks Acuario. Sorry for the delayed response - I only accessed the forum today.

Anyone out there that can do what Graeme referred to?

 I want my heatpump to work with my solar geyser to extract optimum energy provision.

Please contact me Trevor Mitchell 0842221450/ [email protected] 

Thanks

@Graeme McK,

Have a look at my setup post from 8 years ago!

It might be of interest.

 

On 2021/06/07 at 12:16 PM, Pietpower said:

Do you want to connect the heat pump to the hot water out and cold water inlet of the geyser or does it have more connection points or maybe use one of those double inlet connections (can't remember the name)?

I presume you would want the solar to work in the heat of the day and then late afternoon the heat pump must bump up the temp if not hot enough and then not heat at night time so you have coldish water in the morning for the solar to do its thing?