Whether a my-PV WiFi Meter is required or whether control by a compatible manufacturer is possible must be verified in advance by the professional installers.

Just because the logo of manufacturer XY appears on the partner page does not guarantee compatibility with all types and variants of this partner’s products! The professional installers, as providers of our solutions, are also responsible for doing a little homework ahead of time. After all, we don't want to discover on the construction site that (contrary to expectations) a my-PV WiFi Meter is still needed for surplus detection. The end customer, who has to pay for this, will generally have little understanding of such a surprise. However, the "homework" is really just about gathering the necessary information in advance. It doesn’t even take much time.

Solution

• Click on the manufacturer's logo on the partner overview page for the manufacturer that is supposed to control the AC ELWA 2, AC•THOR, or AC•THOR 9s.

• A window will open with a link to a brief guide. It explains how the system works, which device types have been tested or approved for compatibility.

• Therefore, combinations with unmentioned or explicitly excluded types are not possible, and a my-PV WiFi Meter is required for surplus detection at the main connection point.

In buffer storage tanks, the AC ELWA 2 allows for a target temperature setting of up to 90 °C.

However, it's important to question whether such a high temperature is energetically and technically sensible.
In a potable water tank, such a high temperature is clearly not recommended! On one hand, there is an increased risk of scaling on the heating element above 60 °C, and on the other hand, without an installed scald protection, there is also a risk of burns!

In principle, this is possible, but these measurements are not relevant for the regular operation of the my-PV device!

Purely optionally, besides PV surplus measurement, other outputs in a system can also be queried and visualized in the my-PV Cloud. Available outputs include photovoltaic power, battery power, charging station power, and heat pump power.

A very simple way to record these measurements is by using a my-PV Meter. You only need to enter the serial number.

However, purchasing a my-PV Meter is not strictly necessary. For very tech-savvy customers, we have provided the option to manually parameterize these measuring points. This is a free additional option for those who are technically capable! Since this involves data queries from third-party products, we cannot offer support in this case, and we ask for your understanding. For questions about the necessary settings for third-party products, please contact the technical support of the respective company.

Yes, that is possible. The displayed data points represent 15-minute averages and can be downloaded as a CSV file. The "Download CSV" button is available at the top right next to the chart. The file includes the datasets that are activated in the legend to the right of the chart.

In the dialog box that appears, you can specify the time period, the delimiter for the datasets in the CSV file, the time resolution, and (under "Show advanced options") the date formatting.

Yes, that is possible.

To do this, go to "Settings" and select "Systems / Devices".

From the list of your systems, choose the one you want to share, then click the icon to add a user with whom you want to share this system.

In the dialog box that appears, enter the email address that the other user has registered with in the cloud. Please ensure correct spelling! Then determine their role. You can either specify that this user has read-only access to the system and therefore cannot change settings, or you choose "Administrator" and thereby grant unrestricted access to the system.

After clicking the "Share" button, the user will appear in the list. Their role will be visible next to their name, along with a button to stop sharing the system.

Many of our customers have expressed the desire to use the my-PV Cloud on their smartphones. Therefore, we have created the option to save the app to the home screen of Android and iOS devices.

Please first log in to the my-PV Cloud with your smartphone. Since it is a web-based app, it cannot be installed via the Play Store or App Store. The installation process varies depending on the operating system as follows:

Android:

Click on the three dots at the top right corner of the screen (see image) and select the menu item "Add to Home screen."

iOS:

Bei einem iOS-Betriebssystem können Sie die my-PV Cloud App wie folgt installieren: Auf das „Teilen“ Symbol (siehe Abbildung) klicken, dann den Punkt „Zum Home-Bildschirm hinzufügen“ auswählen und schon ist die App am Handy installiert und einfach abrufbar.

Enjoy using our my-PV Cloud as a web-based app!

At first glance, these two things indeed look deceptively similar, and both are operated via a web browser.

The difference is that the web interface is just a locally stored HTML file that allows device access within a local network. To access the local web interface (HTML file) in systems without internet access, download it to your device beforehand: https://download.my-pv.com//currentversionget.php

After downloading this file, no further internet connection is required.

In contrast, the my-PV Cloud is a web portal on a server that also enables remote access from outside the network. To do this, you need to create a user account and then register the device with its serial number and device key in the my-PV Cloud.

For more information, visit the my-PV Cloud information page.

No, unfortunately, this is not possible because the my-PV WiFi Meter alone is not cloud-capable. It always requires either an AC•THOR, an AC•THOR 9s, or an AC ELWA 2 to be integrated into the cloud. Only through one of these devices will the meter data from the my-PV WiFi Meter be visible in the my-PV Cloud.

If the signal source for reporting the PV surplus is within the same local network as the my-PV device, this is not necessary at all.

The my-PV WiFi Meter cannot be connected as a control unit, even though both devices are clearly in the network?

It is confirmed that both devices, the my-PV WiFi Meter and the AC•THOR, AC•THOR 9s, or the AC ELWA 2, are in the same local network when the my-PV WiFi Meter is displayed on the information page.

However, connecting the my-PV WiFi Meter as a control type is not successful with either "my-PV Meter Auto" or "my-PV Meter Manual" in the control settings?

One possible cause could be that the network router is not allowing UDP packets on its port 16124.

Solution 1:

Adjust the settings on the router accordingly to unblock UDP data communication.

Solution 2:

Please contact support@my-pv.com and provide us with the 16-digit serial number of your AC•THOR, AC•THOR 9s, or AC ELWA 2. If your device has an internet connection, we can manually configure the control settings for you!

Since my-PV devices became cloud-capable, the Device Key for integration into the existing data cloud live.my-pv.com has always been included in the assembly manual of AC•THOR and AC•THOR 9s.

However, since the end of 2023, this is no longer the case.

So where can you find the Device Key now?

Solution: You can now find the serial number and the Device Key on the display under Settings >> Cloud Connection.

With the release of AC•THOR firmware version a0021200, my-PV has thus also aligned the handling for AC ELWA 2 in this regard. With the update, the Device Key is now accessible on the device display, not only for the AC ELWA 2 but also for the AC•THOR and AC•THOR 9s. This standardization aims to simplify the overview of our individual solutions with a consistent standard and prevent the Device Key from being lost on the construction site.

The display of the device needs to be recalibrated.

Press the display with a touch pen for at least 10 seconds.

Follow the English-language instructions.

The device will be operational again in 1 minute.

Stratification heating can be realized by two ELWA units. Usually one of the devices is installed in the lower third and one in the upper third of the tank. Both devices are set to the same desired temperature and communicate with each other via the DC cabling.

With the AC ELWA-E, in combination with the my-PV Meter, even up to eleven devices can  be controlled according to priorities. And with Smart-Home control, even more, depending on the type of system.

The AC•THOR and AC•THOR 9s or the AC ELWA-E require information about the available excess PV-power at the metering point in order to control the heater accordingly.

This is received either from the my-PV Power Meter or from a compatible energy management system (inverter, smart home or battery storage).

The data transfer takes place via the local network.

A proper network setup is required for the function!

The my-PV screw-in heating element (3 kW / 9 kW) does not emit heat despite proper installation and control of the AC•THOR / AC•THOR 9s?

Possibility

1. The simplest reason could be that the target temperature has already been reached. The green checkmark on the display in the top right corner is lit permanently.

When using the my-PV temperature sensor, the set maximum temperature is considered the maximum value at the sensor.

Additionally, it could be that the thermostat has already turned off the heating element because the target temperature set on the dial has been reached. In this case, the AC•THOR is disconnected from the load; the details on the AC•THOR show "Load none," and on the AC•THOR 9s, each of the three load outputs shows the information "0."

Thermostat Knob on the Screw-in Heater

Detailed information about the load on the AC•THOR

Detailed information about the load on the AC•THOR

2nd Possibility

The safety temperature limiter (STB) has been triggered. In that case, consider the following:

Electric heating element was not in operation:

The STB was triggered by storage temperatures below -12 °C or by vibrations during transport. Bring the sensor temperature to 20 °C and then unlock the safety temperature limiter.

Electric heating element was already in operation:

The cause of the safety temperature limiter tripping could be damage to the electric heating element or thermostat. Reset the safety temperature limiter only after the cause of the issue has been clearly identified.

To unlock the safety temperature limiter, remove the cover cap with a screwdriver and press the button underneath.

The cover cap of the STB reset button

Issue not resolved? Here's what to do next...

Please contact support@my-pv.com. We will get back to you shortly.

No, the storage just needs to have a G 1 1/2 inch connection. Alternatively, many tanks may also have a revision port where a commercially available adapter can be used.

When installing the ELWA direct current immersion heater, the length of the heating elements (45 cm) and the area of the heat-free zone (9 cm from the sealing surface) must be taken into account during installation.

With the AC ELWA 2 alternating current immersion heater, the length of the heating elements (46 cm) and the area of the heat-free zone (14 cm from the sealing surface) must be taken into account during installation.

You access the web interface of the AC ELWA-E, and instead of the usual interface, you see only 'AC ELWA-E Mainboard Error'?

View in the web browser

3-poliger Stecker mit den Drähten weiß, braun und blau

Fehler nicht behoben? So geht's weiter...

Füllen Sie einfach das Support-Formular aus. Wir melden uns in Kürze.

If you have been using the device for some time and notice an unusually rapid increase in temperature at the ELWA, but the temperature in the hot water tank is not increasing significantly, it could be due to a severe calcification of the heating elements.

Calcification of the heating elements.

Solution

Please remove the device from the storage tank and check the heating rod for any lime deposits. Remove these and clean the elements carefully. Afterward, the ELWA can be reinstalled and put back into operation.

The thermal fuse was likely triggered by a too high temperature in the storage tank. Has the tank become very hot briefly, for example, due to another heat source such as a wood-fired boiler, solar thermal, or a cogeneration unit? Or has the device perhaps been operated without sufficient water?

 The AC ELWA-E is steadily flashing red.

The interval is consistently 1 - 1 - 1 - 1, etc.

In the web interface, the status message "201, Overtemp Fuse Error" is displayed, and the temperature reading may show an unrealistically high value.

The ELWA is flashing red and green.

For the grey ELWA (direct current product), in conjunction with the red blinking LED, the green LED may briefly light up.

AC ELWA-E series

Issue not resolved? Here's what to do next.

Please fill out the support form. We will get back to you shortly.

Video Guide: Sensor Replacement

Watch the video for a simple explanation and useful practical tips:

Is the AC•THOR not adopting the selected settings on the display as desired? For example, when selecting the language, you press the desired language, but it takes another setting?

To do this, touch the display with the stylus or a pen for 10 seconds, and the calibration process will start automatically. Now, follow the instructions on the display.

1. "Press up left corner" - tap the white dot in the left upper corner

2. "Press low right corner" - tap the white dot in the right lower corner

3. "Test somewhere" - touch the display at any point

4. OK - tap

After that, the setup on the display will restart, and the AC•THOR will now accept the selected buttons.

You have configured the automatic hot water backup through time windows, but the backup operation only starts manually and not at the specified time?

Then you may have defined only one of the two time windows across midnight.

Solution

If the backup operation is intended to occur at night, for example, from 9:00 PM in the evening to 5:00 AM in the morning, then set the two time windows as follows: 9:00 PM - 12:00 AM and 12:00 AM - 5:00 AM.

The ELWA is factory-configured for operation as a standalone device or in layer load operation as the upper device. It is likely that the layer setting in the setup mode was unintentionally changed to "lower."

Rotary knob setting

Simply put the ELWA back into setup mode (see installation and operating instructions) and correct the misconfiguration.

In the software, the "lower" setting looks like this (Language selection: English):

ELWA Software. Available for free download.

If the ELWA is supplied with DC voltage for the first time during commissioning, the device waits for ten minutes before using the energy from the PV modules for heat generation. This ensures that the voltage supply is constant every day at sunrise, preventing the ELWA from unnecessarily entering a repeated start/stop state.

Does the blue AC•THOR logo on the front blink at a constant interval once?

 SD card slot on the underside of the AC•THOR (identical position for AC•THOR 9s)

Solution

If you find that the SD card in the slot is indeed loose, briefly disconnect the AC•THOR from the power supply, press the SD card back into the AC•THOR until it clicks into place, and then restore the power supply. After that, the device will boot up normally.

Issue not resolved? Here's what to do next...

Simply fill out the support form. We will get back to you shortly.

Are you controlling the AC•THOR or AC•THOR 9s via "Modbus TCP" or "http" but the power output does not match the specified value?

This may be because the nominal power of the connected heating device is lower than the commonly used device power levels of 3 kW or 9 kW.

Solution

To supply the connected heating device with maximum power, simply "scale" the power specification accordingly.

• AC•THOR: 3,000 W means 100% of the nominal power of the connected heating device is being used.

• AC•THOR 9s: 9,000 W means 100% of the nominal power of the connected heating device is being used.

Your device displays 'Heating finished,' and the green checkmark on the home screen is lit permanently, but the target temperature has not been reached yet?

Screenshot of AC•THOR on the Info page in the web interface

Detailed information about the load on the AC•THOR

Detailed information about the load on the AC•THOR 9s

If the load status is '0' or 'none' (for AC•THOR) or '1:0 2:0 3:0' (for AC•THOR 9s), it may have the following causes:

The shutdown temperature of the thermostat has already been reached. Please consider the current temperature in the storage!

The connection to the heating load is otherwise interrupted.

See also in this FAQ.

A three-phase heating load has been connected to the AC•THOR 9s without a neutral conductor.

The device requires a star point (neutral) at the consumer!

Issue not resolved? Please fill out the support form.

In operating mode M2, two electric heating elements are supplied with PV surplus power one after the other continuously. The upper heating element takes priority. The goal is to reach the desired temperature at the tap point as quickly as possible before the additional surplus heats the remaining storage content. Once the upper heating element reaches the target temperature, the lower heating element is supplied.

If no my-PV temperature sensor is used, the switch is done through the thermostats of the heating elements, and the AC•THOR regularly checks if the upper heating element is available again.

If the my-PV temperature sensor is used, the switch occurs when the temperature at the sensor reaches the set maximum value.

You want to configure the AC ELWA-E, the AC•THOR, or the AC•THOR 9s via Web Setup but don't know the IP address to access the configuration interface?

There are two possibilities:

1. On the display of AC ELWA 2 / AC•THOR / AC•THOR 9s, you can read the IP address assigned to the device by the router.

   Simply press the "i" symbol and scroll to "Details 3/X." The IP address is displayed in the first line.

2.On Windows computers, finding the IP range of the my-PV device is straightforward using the "Command Prompt."

However, it is essential for the computer to be on the same network. In the Windows search bar, type either "cmd" or "Command Prompt." Then, enter the command "ipconfig" in the window and press Enter.

Now, several lines with information will be output, and the default gateway is the IP address of the network router. The first three blocks of this address are then to be entered in the my-PV web interface.

Enter the IP address of the router in the web browser and search for the my-PV device in the client list of the router. However, the prerequisite is that you have access to it. Usually, routers are password-protected.

You can use an IP scanning program freely available on the internet to search your network. Such tools are often available for free. Here's an example.

Your AC ELWA-E or AC•THOR remains on standby. The surplus is not used despite an upright Power Meter connection?

The measuring point of the Power Meter may be installed incorrectly!

In some house installations, three phases lead from the post-metering fuses to the house distribution and three phases to the photovoltaic system. For proper surplus detection, however, both areas must be recorded during measurement.

If the AC ELWA-E or the AC•THOR remains on standby, the current transformers are probably attached to the three phases of the house distribution and the energy from the photovoltaic system remains "unseen".

Solution

If the cross-section of the phases allows it, both wires can be enclosed together by a current transformer. If this is not possible, the current measurement can also be placed between the post-meter fuses and the electricity meter of the energy supply company.

Image excerpt from the Power Meter assembly instruction

If the AC•THOR / AC•THOR 9s displays the error message 102, it means that the function of domestic hot water assurance is active, but no temperature sensor has been connected or activated yet.

To resolve this error, connect the sensor to the AC•THOR and activate it through the display.

To do this, click on Settings (gear symbol), scroll to the 'Sensors' section, and select it.

After that, you will see the serial number of the connected sensor and its current temperature on the display. Click once on this line. Now, the sensor number will be displayed to the right of the shown temperature. This means that this sensor is now active. Finally, save the setting.

In today's world, network technology has become an integral part of many home installations. However, this area, in particular, poses a significant risk of errors during the commissioning of modern systems.

Even my-PV devices like the AC ELWA 2 or the AC•THOR 9s are typically connected to the network with the signal source. Unfortunately, sometimes unknown passwords, firewalls, or other issues can hinder the installation process. This unnecessarily costs time!

As the manufacturer of such products, we always recommend our customers to have their own network router on the construction site. There are no special requirements for such routers. Often, a simple device from the discount store could avoid many delays at your construction site.

You are attempting to set the control type in the web interface of the AC ELWA 2, AC ELWA-E, or AC•THOR, but the selection is grayed out and "Slave" appears?

Signal sources not selectable

This setting can only be adjusted if the my-PV device has the default device number "1." It may have been accidentally altered, for example, with the AC ELWA-E using the rotary knob in setup mode.

Solution

Quite simple. Scroll down on the same page ("Setup page") to the heading "Basic Settings."

Here, set the device number to "1" and save the setting. Afterward, the control type will be selectable.

The control of the AC ELWA-E, AC•THOR, or AC•THOR 9s should be done via 'SolarEdge Manual'?

Then our short explanatory video might help you (in German).

The control of the AC ELWA-E, AC•THOR, or AC•THOR 9s should be done via 'Adjustable Modbus TCP'?

How to easily set the values for connecting to the signal source can be found in the following video (in German).

In the control mode 'Adjustable Modbus TCP,' my-PV devices obtain the feed-in or consumption power from an inverter or Modbus meter. The required register parameters can be set in 5 input fields.

Are all three LEDs blinking on your AC ELWA-E? Is the web interface also not accessible?

It seems you have unintentionally entered the setup mode. This likely occurred because the knob was turned all the way to the left, to the wrench symbol, when the AC ELWA-E was plugged in.

Solution

It's simple: Unplug the AC ELWA-E from the power supply, set the knob to the desired target temperature, and plug it back in.

If the device number was accidentally changed in setup mode, you can correct the setting on the setup page of the web interface. The device number can be set under the "Basic Settings" heading.

Unless you are operating multiple AC ELWA-Es in what is called Multi-Mode, the device number should always be set to "1". Only this way can the control type be selected (further up on the "Setup" page).

The load control of 3 single-phase heating elements is a special form of operating mode M1 for hot water.

The following instructions from the operating manual are important:

Solution

The regular operation for 3 single-phase heating elements can be set with a single adjustment. Simply switch the "Load Priority" accordingly under "Settings" (gear symbol).

You want to control 2 single-phase heating elements with the AC•THOR 9s but notice that only one is regulated, and the other is only switched?

Solution

In its factory setting, the AC•THOR 9s always uses output Out-1 for power control and switches outputs Out-2 and Out-3 when there is sufficient surplus. To implement clean regulation for your case, simply follow these steps.

The AC•THOR 9s is set to operating mode M1.

Supply the heating element with higher priority via output Out-3 and the one with lower priority via output Out-2.

Then, under "Settings" (gear symbol), change the "Load Priority" to the setting "Out 3-2-1."

This way, the regulation begins with the heating element with higher priority. When there is sufficient surplus, it is supplied with maximum power, and the heating element with lower priority is regulated.

With this application, clean zone loading can be implemented in larger thermal storage systems, and surplus energy can be introduced into two separate storage systems. For example, priority can be given to a hot water boiler over a heating buffer storage

Should you find yourself utilizing the AC•THOR 9s equipped with three individual heating elements and three temperature sensors, yet noticing a deviation that the control is not switching between the heat generators as expected, it's possible that the sensor assignment has been swapped.

No, ELWA is an all-in-one solution. In addition to the heating element, it also integrates the control and regulation electronics, temperature measurement, and a rotary knob as the operating element directly on the product.

No, you always need only those components described in the installation manual.

However, local regulations must also be adhered to.

During registration, a link is automatically sent to the provided email address. If you haven't received this email, please check the following:

• Check the spam folder of your inbox.

• Verify if the email address you entered might be incorrect.

• Ensure that your inbox hasn't reached its storage capacity.

The AC•THOR and AC•THOR 9s or the AC ELWA-E require information about the available excess PV-power at the metering point in order to control the heater accordingly.

This is received either from the my-PV Power Meter or from a compatible energy management system (inverter, smart home or battery storage).

The data transfer takes place via the local network.

A proper network setup is required for the function!

For every my-PV product, there is a datasheet as well as an operating and installation manual. All these documents are available to you at any time in the Downloads section of our website.

Use the search functions to quickly find the desired information within these documents!

In all houses with a PV system and a hot water boiler, the PV surplus can be used for domestic water heating.

Optional: In buildings with low heating demand, electric space heating can also be supported from photovoltaics.

Maximization of self-consumption is the goal!

This primarily depends on solar radiation but also on the heat withdrawn from the storage during heating through hot water usage or by the heating system.

Nevertheless, a theoretical consideration can be made assuming constant conditions. To heat 1 liter of water by 1 degree, an energy amount of 1.16 Wh is required. For instance, a storage tank with a capacity of 300 liters, heated from 10 °C to 60 °C, could store 17.4 kWh of energy. To accommodate this energy in the storage with a constant 2 kW heating power would take approximately 8.5 hours.

For a more practical, year-round assessment of the system, it is recommended to check with the my-PV Power-Coach.

As it is the case with heat pumps, the seasonal performance factor (SPF) describes the ratio heat generation to electricity demand (without household electricity consumer). However, while a heat pump additionally receives energy from the environment, the energy for my-PV products comes from the sun. The big advantage is that electricity is now available instead of heat for energy distribution. "Cables instead of pipes" make the system much easier and less expensive. A fact that also has a significant impact on maintenance costs.

Thanks to smart excess management, AC•THOR draws less power from the public grid than heat pumps do. For all those who want to build or renovate a house, AC•THOR offers a considerable potential for savings: The building services can be installed in the smallest space and save up to 30% of the acquisition or operating costs compared to heat pumps.

How much electricity from the grid is required can be directly influenced by the size of the PV system. This is easily possible for energy-saving detached houses with, for example, 10 kWp PV.

In addition, a heat pump can "only" generate heat. There is no contribution to the electrical consumers in the building. In contrast, photovoltaics gives priority to normal household electrical consumers before heat generation and thus contributes to the reduction of operating costs to the highest degree.

Depending on whether only hot water has to be heated or the space heating is supported, a PV system between 3 and 10 kWp makes sense for a detached house.

All popular poly, mono and thin film PV modules. Only the voltages and currents have to be considered!
The ELWA operates in a voltage range of 100 -360 VDC.

Click here for our practical calculation tool.

The advantages are manifold. In new buildings this means significantly lower investment costs.
In the refurbishment considerably less interference with the building substance than with the replacement of a water-based heating system.

In addition, PV yields can be used in all energy sectors of the house (electricity, heat, electric mobility).

Nothing happens. The device continues to work normally. Only the optional boost-backup function is not available.

In an ELWA system, no power is fed into the grid. Any excess energy remains unused as in a solar thermal system. The main technical difference is that this does not result in any material fatigue compared to solar thermal energy. 

In addition, the share of excess energy with ELWA is very low. Practically it is 5-8 percent. That would be about 100-150 kWh per year for a 2 kWp system, or at best 15 euros per year.

If you need an inverter, an electricity meter with meter rental, a feed-in point and the grid connection, then the additional effort is not worth it at all.

Linearly controlled heating elements are electric heat generators which output can be adjusted from 0 to 100%.

They are not switched off and on by a thermostat as it is the case with conventional thermostats.

This linear power function is essential for operation with photovoltaic electricity because the available power is constantly changing due to irradiation and other consumers in the house.

Pay attention to the technology: Only so-called "high-frequency clocked" converters do not cause mains disturbances and can be connected without any problems.

ELWA is not only much easier, but also much cheaper than solar thermal systems. This applies both in a single-family home and in apartment buildings. The advantages over solar thermal are multifarious:

• Due to the elimination of the pipes you can save up to 90% valueable copper

• No cost-intensive components like pumps, valves, expansion tanks, frost protection mixtures, insulations,...

• Photovoltaic heating even works with low solar irradiance

• No lossy start-up procedures (clocking, loop warm-up)

• Maintenance-free (frost protection)

• No material fatigue during system downtime

• Efficiency independent from system temperature

• More efficient at lower ambient temperatures

• Nearly loss-free energy transmission from the roof to the boiler

• Mounting in the boiler/tank quickly and not complicated, even when tank is filled

• Nearly no internal consumption (2W)

• Grid feed-in of the energy surplus instead of stagnation (with AC ELWA and AC ELWA 2)

• Cost development and technical development of photovoltaics are rapid

• ELWAs can be used decentrally, thereby no distribution losses in multi-family houses.

The solar energy is converted into heat right where it is needed!

The answer to this question essentially depends on whether you have a subsidised feed-in tariff. If you feed in without an increased feed-in tariff, then you will receive about 3 to 6 euro cents per kWh, depending on the country. In Germany, you still get 10 to 12 Euro cents feed-in tariff for small systems.

If you use this energy yourself, then it corresponds to the value of the displaced energy source. With gas, for example, one kWh costs approx. 8 euro cents, then the efficiency and maintenance costs of the gas appliance are added, i.e. another 2-4 euro cents. With biomass, the costs for efficiency and maintenance are even higher.

Thus the self-consumption pays off under these conditions. In addition, they displace depending upon heating system fossil energy consumption. This improves your CO2 balance and your ecological footprint.

Because the AC•THOR is an alternating current (AC) device. In an off-grid system, it requires a PV inverter and a battery inverter that performs frequency modulation depending on the battery charge status. As the frequency increases, the AC•THOR increases the output of heat. In off-grid systems without frequency control, the power control of the AC•THOR must be done differently, for example, through a higher-level control system, such as an energy management system.

Yes. Depending on the number of available screw-in points, multiple devices can be used, completely independent of each other.

It is also possible to connect 2 ELWAs to one module string and have them operate in a Master/Slave principle. This allows for thermally optimized loading in a larger thermal storage system. The upper device takes priority, ensuring that the desired target temperature will be reached more quickly.

No, a combination with a battery is not possible.

ELWA was developed for thermal storage in hot water boilers or heating buffers and uses power directly from PV modules. Parallel operation with a battery is not provided on the direct current side.

Yes, AC•THOR can also support conventional, water-based heating systems.

For example, the pellet boiler or the heat pump for hot water preparation do not need to be started in summer.

Combined operation with heat pumps is also possible: Since heat pumps cannot control their electric power input linearly, the AC•THOR takes over the exact control of the PV-excess output with a heating element. This optimizes your self-consumption significantly.

Yes, with my-PV Power-Meter. With the feed-in point, the my-PV Power-Meter detects whether surplus energy is available and transmits the information to AC•THOR or AC ELWA-E.

No. Both devices can independently control the power on their own.

Advantage of AC ELWA-E: It is a fully integrated solution. An extra heating element is not required. This has significant cost advantages.

Advantage of AC•THOR: Almost every electric heat generator can be linearly controlled. So also existing immersion heaters or even those with a connection thread other than 1.5 inches.

In addition, AC•THOR can also infinitely control two heating elements one after the other. As a result, stratification heating with two elements can be realized at minimal costs.

No. You can use the AC•THOR also for water heating only.

The connection of an electric heating system is optional.  If a buffer storage is available, of course, the water-based space heating can also be supported. The heating element is then installed in a buffer tank, or 2 heating elements (hot water boiler, buffer tank) are connected.

Yes. AC•THOR system is one of the cheapest on the market in terms of acquisition and operation.

In existing buildings it significantly reduces the load on your existing heat generation system, in new buildings it can completely replace conventional water-based building services.

No, it is an AC device and plugged into a standard mains socket. From this it takes only as much power as is currently available as surplus.

Since there is no interconnection with the components of the photovoltaic system, it is possible to combine them with all commercially available grid-connected PV systems.

Solar thermal energy is often said to have an efficiency of 80 percent. However, this is only a snapshot taken at the collector test bench (without any heat release), that means: the value has no practical relevance!

It is much more objective to compare the annual energy yields of both technologies. Well-functioning solar thermal systems with flat-plate collectors supply about 350 kWh of heat per square meter per year. A photovoltaic system with the same area earns about 200 kWh per square meter. In between there is a factor of 1.7. That means, for a typical hot water system you need 6 square meters of thermal collectors, or 10 square meters of photovoltaic modules. But this only matters if there is not enough space on the roof, because the sun is shining for free and there is no direct correlation between cost and efficiency.

Incidentally, the area factor for solar thermal energy was still 2 in 2015, another indication of how fast the technology is evolving.

The standard 1.5 inch thread makes ELWA or AC ELWA-E easy to screw into storage. 

This is possible even when the storage tank is full. Learn here (German) how this works. 

Yes! »Cable instead of pipes« leads to significant savings in operation by avoiding the thermal distribution losses on a ring main. Also hygiene regulations are easier to fulfil.

The energy of the sun is converted into heat at the place of consumption!

The AC•THOR is sometimes misunderstood. It is not.

Technically speaking, it is an AC power controller.

It linearly controls the power of electrical heat sources as a function of PV energy supply and heat demand.

No, it is an AC device and plugged into a standard mains socket. From this it takes only as much power as is currently available as surplus.

Since there is no interconnection with the components of the photovoltaic system, it is possible to combine them with all commercially available grid-connected PV systems.

Yes! Generating hot water with photovoltaics allows for water heating using electric water heaters within the residential unit. Despite this, high solar coverage levels of 50 to 60% can still be expected.

This results in significant operational savings by avoiding thermal distribution losses in the pipelines.

In centralized hot water supply, distribution lines must always be maintained at approximately 60°C to prevent Legionella formation. This leads to substantial losses.

ELWA does not require any additional components, apart from the photovoltaic system (without an inverter) and a thermal storage unit where the ELWA is installed.

According to our recommendation, direct solar-electric space heating only makes sense in buildings with a low heating energy demand. By this we mean objects with a specific energy index of maximum 50 kWh/m² (low-energy house, or better).

Depending on the area heated, there is an annual energy requirement. In the case of a single-family house, for example, this should be in the order of about 4,000 kWh, i.e. roughly the same amount of energy that is required for electricity and hot water generation in such an object. The power of the photovoltaic system should then be in the order of 8 to 10 kWp.

Building the space-heating system purely solar-electric, is only useful in houses that have been built according to low energy standards or that are thermally renovated!