Making renewable energy production more economical&efficient



  • Hi,
    I just wanted to mention some ideas that could make renewable power production at home more economical and efficient (so actually benefit the owner financially, and benefit the environment too.

    The ideas were first posted at https://forum.athom.com/discussion/1648/smartphone-less-homey but I think they're probably of more use here (in cooperation with the http://domoticz.com/ system -so replace "Homey" with Domiticz-system in the below text- )

    This is the idea for the improving the gain from PV panels:
    "Also, there may be some things that are nonetheless best automated like for instance changing the tilt of your solar panels at certain moments during the year (see http://www.solarpaneltilt.com/ ). Doing this manually would mean you'd need to climb up unto your roof to change this, which is hazardous. Something like this could be done with a oil-filled piston for instance (I never seen any commercial device like this really, but possible in theory). The piston could be used to just reduce/increase the height of the PV panel (or solar thermal collector for that matter). If the PV panel is mounted on a better platform (which has electric motors able to change both the horizontal and the vertical position (like this design ), then the efficiency gain can be even higher. Not only can it then follow the
    sun perfectly using an averaged out trajectory (for every day of the entire year), but it can even use a different trajectory for every day (so use one of 365 trajectories), so executing the following of the sun just plain perfect. The reason why an averaged out trajectory is a bit worse than a trajectory for that period of the year is because the sun path (see wiki: sun path) changes every single day a tiny bit (exact location where the sun rises in the east and sets in the west changes every day). You'll notice that the design linked has a PCB, but the PCB's used would generally use an averaged out trajectory; with the Homey though, making and using a wide range of trajectories wouldn't be a problem at all.

    Here is the idea detailing the making of a device able to start/stop renewable power production plants during peak/off-peak hours:
    It could also be useful to start combined heat and power systems (ie engines on pure plant oil) and supply it to the mains energy grid during peak-hours, and for instance recharge your off-grid batteries (or refill the pond of for your pumped-hydro system) during off-peak hours. Also, besides simply using more power during off-peak hours, and supply back produced power during peak hours, devices (like washing machines) can be switched on during off-peak hours. My intitial idea years ago was to just use a time-switch for that (see here ) but really the Homey can do this as well, and probably even do it better as it would even allow using dynamic peak/off-peak metering and use (at present, such timetables don't yet exist -as the power supply companies aren't yet fully ready for it-, but they're experimenting with it all ready.

    Here's the idea of having a device meter the power used in the house at different times of the day (something like this could be done with something like a https://en.wikipedia.org/wiki/Kill_A_Watt -the data thereof can be manually written down and used to correct the system one uses to switch on/off devices ; an alternative is something like wirelessly controlled socket switches -see http://www.fifthplay.com/en/news/press/smart-energy-box - 😞
    Besides that, it's also useful to constantly measure all the power
    used in your house (and display all active appliances), at any given time. That's useful for energy stacking purposes. Energy stacking is of great importance for houses that are completely off the grid (so not semi-off grid buildings -which have energy storage, but are still connected to the mains electricity grid too-, but true off grid buildings)."

    I'm thinking that you guys are best placed to make these things mentioned, based for example on the domoticz-system, by combining it with other (mysensors.org) sensors. I'm not familiar enough with these, so can't do it and I'm also not actively pursuing this any more; you guys however could make the ideas work and provide the benefit for people and environment.



  • I also forgot to mention that depending on the renewable power plant used, and whether or not you have a battery system, the switches the system would need to make use of could either be direct-current (DC) or alternating current (AC) switches. This, as if you have say an internal combustion engine (on straight vegetable oil) you might best not have a battery system at all -as the fact that you're using a fuel means you can all ready generate power when you wish-. So, you can have it producing AC power which can then be used directly (at your home), or routed back to the mains electricity grid by using the (AC) switch. If you however have say a small-scale wind turbine, you would want to connect this to a battery (as you can't stop/start this as you please), and have the wind turbine generate DC-power instead. It makes sense to then put the (DC) switch here behind the (inverter connected to your) battery bank. So not between the battery bank and the wind turbine ! That way, the battery bank can be constantly recharged whenever there is wind, and you can use the power from that battery bank during off-peak hours at your home, and route it back to the mains electricity grid during peak hours.

    Further notes:

    The AC switches you might use may also come in different versions, depending on the what mains electricity grid you use it on (the US has 120V, 60Hz, in the EU, it's 230V, 50 Hz, see https://en.wikipedia.org/wiki/Mains_electricity_by_country).

    The energy output monitoring (for energy stacking) function would only make sense on the battery-based system obviously, and is of no use on the simpler AC power plant version.

    A problem that might arise with the simpler AC power plant version is that it may be difficult to match the load to the generated energy from the power plant. If really unsurmountable, use the DC power plant setup with internal combustion engines as well.

    Regardless of the power plant setup used, you'll always need to have the power flow trough a double tariff electricity meter (see https://en.wikipedia.org/wiki/Electricity_meter#Multiple_tariff_.28variable_rate.29_meters ) to route it back to the mains electricity grid.

    Finally, if you're wondering why I mentioned to put an inverter in the DC power plant system (behind the battery bank): that's because you need it in AC to be able to route it back to the grid, and when you just use it around your house, you still need it as well since most equipment in your house is AC-based.



  • Some notes on how the singleboard pc (also used by the domoticz software) would become aware of when it's currently an off-peak or a peak-hour:
    as mentioned, this is best done using a dynamic system (else it's equally useful to just use plain time switches and not have a singleboard pc running at all to get this done).

    For the dynamic system, I mentioned power companies can use a sort of PLC (see https://en.wikipedia.org/wiki/Power-line_communication ) system. That would have the advantage that the power company could use a same power cable to also transfer the data. This might be a bit too complicated for power companies to set up though in retrospect. Probably better is that they just run an rss-server instead. A seperate rss-server would need to be be running per country, or even per power company.
    Since it would be dynamic, it could even use a range of prices depending on the power production/demand ratio at that particular moment. The switches the singleboard pc then control can even be set to start/stop depending on the price at that moment, and stopped after a certain delay -this is most useful for say washing machines, ... as else there might be increased wear-). As all ready mentioned though, it's something power companies would need to set up, and since that isn't the case yet, we probably best just make a simpler, static system ourselves. That static system can then also function as an (off-line) back up, even when the dynamic systems are being made.

    For the static system: it would be most useful to make this as something that's user-settable (so that the user can change the standard settings to match the off-peak/peak hours his local electricity company set out, exactly). It should be made in such a fashion that even if there's no internet access on the singleboard pc, it can still be used. Similar to the dynamic system, the different switches can be activated/deactivated by the singleboard pc upon reaching a certain price range. Unlike the dynamic system though, there will off course only be 2 prices: that of the off-peak hours, and of the peak hours. These prices are best also made settable.

    The singleboard pc tend to use linux as the OS, so it needs to be written in say C++
    Any volunteers ?

    PS: besides the ability of this program to activate and deactivate power plugs (i.e. via the fifthplay smart energy box hardware noted above), we'll also need special hardware to be able to route power in one of 2 possible directions. This is only needed though for the renewable power plants at home, when we use the simpler system mentioned. For the more complex one (with a battery system), it's not needed, as we can put an activatable/deactivatable switch both before and behind the battery bank.


 

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