connect Solaredge Smart Energy Hot Water device to HPHW Tank?

[Steeler.Fan]

I have a heat pump hot water (HPHW) tank, with two 5 kW heating elements that I would like to connect to the Solaredge Smart Energy Hot Water device, which is a solar diverter. I can put the HPHW tank in the electric only mode from 9a-5p. I hoped to control the electricity going to the upper thermostat with this diverter so that it would only power the upper electrode when there was surplus solar generated electricity. (I have an electric meter wired to monitor import/export). Normally the power connects to a control board, which then powers either the HP compressor or the upper or lower thermostat depending upon the mode setting (HP, Electric, combined or Vacation) and the temperatures sensed at each thermostat. The upper thermostat is the master thermostat and will energize first if the HW tank is filled with cold water.
Is this possible?
I called SE tech support but they referred me to SE design and Sales, who has not returned my calls.
Thanks in advance for any advice or suggestions.

[Ampster]

Which HPWH do you have? I have a GE Geospring HPWH and am using a Nuerio with IFTTT to change my WH temp when I have solar production. I did not know SolarEdge had a Smart Energy Hot Water device. I will research and get back to you.

In the meantime, is your question specifically about the SolarEdge device or about how to connect to the upper heating element of your HPWH?

[Steeler.Fan]

Answers: Rheem Prestige 80 gal HPHW tanks (2). SE Smart Energy Hot Water device: SMRT-HOT-WTR-45-S1

I have a 3300 SF all electric home with central AC, pool pump, HPHW pool heater, 2 HPHW tanks, 1-2 EVs and an Ice Bear 20 (ice battery) in a warm, sunny area of the US. My solar system is 19.6 kWac with a SE inverter with electric meter that can sense when I start to export. When I export I get $0.10/kWh and pay $0.36/kWh to import energy. On sunny days I will surely export unless I maximize self consumption. One way to increase self consumption would be to super heat my HW tanks(2) to >140F whenever I have surplus solar.

The SE Hot Water device can divert surplus power to one of my HW tank electrodes. Some diverters can attach to 2 electrodes in a HW tank and when the target temp is reached by one electrode, these diverters can switch power to the other electrode to raise the entire tank to the desired temp. Since the SE Hot Water device can only power one electrode, I would probably choose the upper "master" electrode of one HPHW tank.

Using a diverter with a smart HW tank is more complicated. I have to choose an appropriate daytime setting for my HPHW tank. With my HPHW tank, I can set a daily schedule that dictates mode (HP, Electric only, HP & electric, Vacation) and target temp at different time periods during the day. I am not likely to begin exporting before 9 am and after 5 pm and maybe more likely 10 am to 4 pm or even 11a-3p.

I could start the solar day in HP mode with temp set at 110F, then switch to 'Electric' mode and 140F+ temp when exporting started. When exporting stopped, I would want to switch back to HP mode at 110F. Maybe it would be better to use the SE API to signal when exporting has begun and use an IFTTT system to switch mode and target temp and back again when export stopped or pause. Is this what you do with your Neurio IFTTT system?

I read that Alexa can communicate so that I could manually tell Alexa to automatically switch my 'hot water tanks' to electric mode and change temp to 140F whenever surplus solar electricity is generated. Then I would have to reverse that latter in the day. That approach wouldn't work with intermittent cloud cover. Is there a better way to automate my use IFTTT to super heat my HPHW tanks when I have excess solar?

[Ampster]

Answers: Rheem Prestige 80 gal HPHW tanks (2). SE Smart Energy Hot Water device: SMRT-HOT-WTR-45-S1

I have a 3300 SF all electric home with central AC, pool pump, HPHW pool heater, 2 HPHW tanks, 1-2 EVs and an Ice Bear 20 (ice battery) in a warm, sunny area of the US. My solar system is 19.6 kWac with a SE inverter with electric meter that can sense when I start to export. When I export I get $0.10/kWh and pay $0.36/kWh to import energy. On sunny days I will surely export unless I maximize self consumption. One way to increase self consumption would be to super heat my HW tanks(2) to >140F whenever I have surplus solar.

My brother has a home in Lahaina and is in the same boat as far as rates are concerned. I superheat my HPWH tanks but for safety purposes installed a mixer valve so the water at the tap can never go above scalding.

The SE Hot Water device can divert surplus power to one of my HW tank electrodes. Some diverters can attach to 2 electrodes in a HW tank and when the target temp is reached by one electrode, these diverters can switch power to the other electrode to raise the entire tank to the desired temp. Since the SE Hot Water device can only power one electrode, I would probably choose the upper "master" electrode of one HPHW tank.

I have installed a Rheem in a rental but am not familiar with the workings of the internal circuitry with regard to how it switches internally between Heat Pump mode and resistive mode. My general understanding of the resistive elements in an electric water heater is that either the top or the bottom element are powered at a time and the internal thermostat controls that. First the top heats, then the bottom. The thermosat makes sure only one at a time is powered. The software actuated switch I mentioned above works before that. I honestly would not want to try to find that spot and try to intercept that and make sure I had L1 and L2 wired correctly for either scenerio, but I understand why you would want to do that when you have solar. You want the default lower temperature to be the more efficient mode so that you never run out of hot water.

Using a diverter with a smart HW tank is more complicated. I have to choose an appropriate daytime setting for my HPHW tank. With my HPHW tank, I can set a daily schedule that dictates mode (HP, Electric only, HP & electric, Vacation) and target temp at different time periods during the day. I am not likely to begin exporting before 9 am and after 5 pm and maybe more likely 10 am to 4 pm or even 11a-3p.

I could start the solar day in HP mode with temp set at 110F, then switch to 'Electric' mode and 140F+ temp when exporting started. When exporting stopped, I would want to switch back to HP mode at 110F. Maybe it would be better to use the SE API to signal when exporting has begun and use an IFTTT system to switch mode and target temp and back again when export stopped or pause. Is this what you do with your Neurio IFTTT system?

I read that Alexa can communicate so that I could manually tell Alexa to automatically switch my 'hot water tanks' to electric mode and change temp to 140F whenever surplus solar electricity is generated. Then I would have to reverse that latter in the day. That approach wouldn't work with intermittent cloud cover. Is there a better way to automate my use IFTTT to super heat my HPHW tanks when I have excess solar?

That is what I do with IFTTT which speaks to the GeoSpring but I could not find an interface from IFTTT to do settings in the Rheem. I think there is a way to do that with API signals but the learning curve with API is steeper than my abilities with simple logic and triggers in IFTTT. My fallback is I have a nephew that was an IT Director for a large supermarket chain and necessity may mean I have to engage him in my solution when I get a Rheem which may be sooner than later because I have repaired my Geospring once and will be replacing it with a Rheem soon. I like the features of the Rheems and there are some other advantages with some DER credits I could get montly.

I am interested if Alexa can do that. If Alexa can do conditional loops and Alexa has some way of being informed about solar production then the logic is something like:
If solar production exceeds (your value) set HPWH temp to 140 degrees. When solar production falls below your value set HPWH to 110 degrees. I assume that logic can be set to run from something like 9AM to 5PM or what ever time you want to for your solar window.

I am not sure what you mean by diverter but maybe it has something to do with two tanks. That might be another workaround to store heat but it might require a recirc pump.

[Steeler.Fan]

All new construction in my area requires a cold water mixing valve so if I super heat my HW tanks, no water exits greater than 120F.
I have just started to look into using IFTTT with my Rheem HPHW tanks. I bought the EcoNet attachment for both. Below is a link to the Amazon page showing how Alexa can be used to control my Rheem HPHW tanks thru Econet, including how to change mode and temp setting:

https://www.amazon.com/Rheem-EcoNet/dp/B079X3JL45

My knowledge of using API to extract data is very limited. I do know that one of the data queries will return energy or power exported, which I think is the critical parameter. I guess that I would be interested in when export power > 4-5 kW. If I can managed to change my HPHW mode to electric mode and raise target temperature to 150F, that would add a load of up to 5 kW so I suppose that I don't want to make this change when export power < 4-5 kW.

The nice thing about the Solaredge Smart Energy Hot Water device (diverter) is that if you only have 1 kW of power being exported, it only diverts 1 kW of power to you HW tank.

I don't know if one can write a script to have Alexa do condition loops but I hope there is something can can do so such as Amazon, Harmony or Wink.
I think the desired script would be something like:
Check export power value every 5 min from 10 am to 5 pm. (SE API limits queries to 300/day.) If export power exceeds 4 kW, set HPWH mode to "electric" and set temp to 150F. Else do nothing. If mode was changed and export power value is now < 4 kW, switch mode to HP and set temp to 110F. Looking at my solar generation curves, intermittent clouds occur frequently and I don't want my HPHW tank to stay in the electric mode with a set temp of 150F when I don't have excess solar. However, if it was cloudy all day or if it was persistently sunny after say 10 am, I wouldn't be changing mode & set temp frequently.

[Steeler.Fan]

Unless I can find a way to connect the SE Smart Energy Hot Water device to my smart HPHW tank, I thought of another alternative. I could buy a 40 gal electric HW tank and plumb it in series with my other 2 80 gal tanks with the small tank closest to the cold water input. I would also need to establish a recirculation loop with pump between the 3 tanks so that I could mix the water that my diverter had heated in the small tank into the other 2 80 gal tanks. That would give me 200 gal of HW storage. Then I could connect the SE Smart Energy Hot Water device to the 40 gal electric HW tank. I may have to buy a SE Smart Energy Switch to power the recirculation pump. This 3 tank system could be very effective at self consuming 5 kW per hour as long as I had surplus solar but somewhat costly with the purchase of the 40 gal tank, record pump, SE Smart Energy Hot Water device and SE Smart Energy Switch. I don't know if the SE Smart Energy switch is available yet in the US but it is available in Europe, Asia and Australia/NZ.
Solaredge also sells a temp probe that I could install in the 40 gal tank and use it to shut off the SE Smart Energy Hot Water device if the temp > 150F.

[J.P.M.]

Unless I can find a way to connect the SE Smart Energy Hot Water device to my smart HPHW tank, I thought of another alternative. I could buy a 40 gal electric HW tank and plumb it in series with my other 2 80 gal tanks with the small tank closest to the cold water input. I would also need to establish a recirculation loop with pump between the 3 tanks so that I could mix the water that my diverter had heated in the small tank into the other 2 80 gal tanks. That would give me 200 gal of HW storage. Then I could connect the SE Smart Energy Hot Water device to the 40 gal electric HW tank. I may have to buy a SE Smart Energy Switch to power the recirculation pump. This 3 tank system could be very effective at self consuming 5 kW per hour as long as I had surplus solar but somewhat costly with the purchase of the 40 gal tank, record pump, SE Smart Energy Hot Water device and SE Smart Energy Switch. I don't know if the SE Smart Energy switch is available yet in the US but it is available in Europe, Asia and Australia/NZ.
Solaredge also sells a temp probe that I could install in the 40 gal tank and use it to shut off the SE Smart Energy Hot Water device if the temp > 150F.

If you haven't done so already, I'd suggest you consider ways to handle what happens if/when the stored water temp. exceeds upper limits. Aside from the possibility of a relief valve lifting at some pressure and/or temp., some DHW systems will limit electrical input if the water temp. gets beyond set limits.

[Steeler.Fan]

Good suggestion JPM
I talked with the SE representative for my part of the US today. He tested the SE Hot Water device in some homes. It is not available yet but should be later this year. He didn't know if the Smart Energy Switch or Socket devices would ever be available in the US. He explained that their SE Hot Water device essentially replaces the "grey box" timer on HW tank power lines and can't be connected to HPHW tanks. However, I use a zwave home automation system and can install a zwave connected temperature sensor on the small HW tank. From say 9a-5p I could query this temp sensor to see if it was > 130F. If so, I would turn on a zwave connected electrical wall outlet installed nearby. That outlet would power my recirculation pump only when hot water was in my 40 gal tank from 9a-5p.

[Ampster]

I also found out the same thing while trying to research that device as I promised. One thing that did pop up was a device that uses a CT clamp and can control a relay when the CT clamp senses current. It used a cloud interface and I put the app on my phone but unless I install connect to the device I can't tell if it can actually program a trigger current but it does have time controls. It is only $59 on Amazon which isn't bad for the ability to trigger a relay when the solar is operating. Here is a link:

https://www.amazon.com/dp/B07ZHLP7R8/?coliid=I2GV0WMYUNZVJ7&colid=35NCZ69T7ZYUX&psc=1&ref_=lv_ov_lig_dp_it

[Steeler.Fan]

My utility room won't accomadate an additional 40 gal HW tank very easily so my thought to add a third HW tank with recirculation loop may not be feasible.

The Rheem EcoNet is compatible with the Wink Hub & Logitec Harmony Home Hub. Anyone have experience controlling an EcoNet device via those hubs? Alexa can control an EcoNet device through verbal commands but can one write a script to do that and on what platforms could the script run?

[Ampster]

My utility room won't accomadate an additional 40 gal HW tank very easily so my thought to add a third HW tank with recirculation loop may not be feasible.

Could you set the temperature in the last tank higher and circulate water between them when solar is generating? I guess would be the same as setting both tanks at a high temperature but without the solar generation constraint, just a time of day thing.

The Rheem EcoNet is compatible with the Wink Hub & Logitec Harmony Home Hub. Anyone have experience controlling an EcoNet device via those hubs? Alexa can control an EcoNet device through verbal commands but can one write a script to do that and on what platforms could the script run?

Some old posts on a forum I discovered when trying to learn more about the Alexa capabilities suggested that at that time the temperature was limited to 90 degrees because it only worked for Econet thermostats. I will look at the Wink and Logitec hubs to see what my future choices would be.

[Steeler.Fan]

New Idea: Found Rheem Hot Water Booster, which is an add on device. I could install a booster between my 2 tanks along with a recirculation pump and a recirculation line between the outlet of 2nd tank and inlet of 1st. I can write a script to query my inverter for the export power value & turn on booster & recirc pump when export power > 4kW. Recheck every 15 min. I use a Veraplus for my home automation system.