The Green Smart House Solution
Why Smart House Systems?
Today, lots of companies are talking about the splendid opportunities their internet connected smart house systems offers. In the house of the future, the refrigerator can suggest recipes and order food all by itself, the coffee is ready for you in the morning and you can even talk to the systems, but are features like these really useful or just gimmicks? How can a refrigerator know your plans for the future and what you intend to serve for any guests so that such a feature can be a real help for the lots of extra money it costs and not just be an annoyance you will probably switch off once the initial excitement for all the new features has cooled down? The recipes can still be found on the internet. Over 20 years ago, IO Technologies - now Prevas - connected the first coffee maker to the internet, but even though the number of internet applications have exploded enormously ever since, there are still very few connected coffee makers - simply because there is no need for it for ordinary people. You still have to add water and coffee so no time is saved and you don't want to lose aroma from an open coffee filter during the night so why spend the extra money this feautre costs and perhaps even open a backdoor into your computer network if the coffee maker is not safety updated? At a first glance, it may also seem very nice that you can talk to the system and in this way get your hands free, but if this feature is implemented by means a cloud solution where everything you say may be transmitted out on the internet and people you don't know may be listening to improve the systems, it might not be such a good idea after all. Your privacy and safety is gone and hackers may also listen and use it to blackmail you.
To our oppinion, a smart house system should not just give you more or less useful gimmicks, but first of all value for money.
- In a green world it should at least pay for itself in the form of saved energy and resources for production, recycling and disposal of all components including any batteries, and it is very desirable that it can utilize solar energy in a very efficient and cheap way so that this possibility becomes available to many more and may even be standard in many new houses.
- It should add new handy features, but without making it clumsy to use and/or maintain in daily life. For example, it may be convenient that you can control the light from an app on your smart phone, but you don't want to find the right app and perhaps even the reading glasses every time you want to switch a lamp on or off or dim it, and you don't want to replace batteries all the time in sensors, contacts and actuators like radiator thermostats and door locks to keep them operational.
The traditional ad-hoc method
For many years, lighting in buildings has been implemented with simple point-to-point connections between wall switches and lamp outlets in the ceiling. This is easy to overlook and install by any electriciant, but it is very difficult to rebuild - especially in low energy houses with an unbroken vapor barrier between outer walls where it may be necessary to remove the ceiling. It is also very difficult and expensive to make green sustainable solutions and add even the simplest smart-house features like dimming.
- You can replace the wall switch with a mains dimmer, which reduces the average mains voltage, but most dimmers can only control one lamp and therefore cannot replace a double switch and there is no way to implement more advanced features like multi-way (landing) switching, all-off, remote control and change of color or scenes. Because most LED-bulbs have a capacitive input, the dimmer needs to be a trailing-edge type, which is much more expencive than a simple leading-edge TRIAC dimmer, and the low current of LED lamps may create big problems. There is usually a minimum wattage, the flicker-free dimming range is very limited - often to only 10 %, which the eye only regards as a 2.7 times reduction in light intensity, and induced currents may get the LED lamps to glow all the time.
- You can replace the LED-bulb with someone with wireless control such as WiFi, Zigbee or Bluetooth, but to utilize more advanced features than simple on/off, the bulb needs to be switched on permanetly and must therefore not be forgotten in off-state, and it may be necessary with routers and the use of advanced control devices like smartphones. Besides, wireless communication may be disturbed by other communication in the same band, may be hacked and jammed if just a single device on the network is not safety updated, may disclose information about your behavior and can be very difficult to setup.
- You can replace the mains voltage LED-bulb and with that perhaps also the entire lamp with someone, which is driven by a separate LED driver with remote control such as 0-10V, 1-10V, DALI, KNX or DMX512. This makes it necessary to rebuild the lamp outlet, ensure proper cooling for the LED driver, which can be very difficult if it must be mounted in insulation material, draw new cables for the control system and add and use more advanced control devices than simple wall switches.
No matter what you choose, you will spend a lot of money and get a lot of problems and non of these solutions are green and sustainable. Besides, many smart-house systems are too complex to handle for an ordinary electrician and get obsolete way too fast. If the system cannot easily be serviced, safety updated, rebuild and expanded for a very long period af time and not just by the ones, who have installed it, it may reduce the selling price of the house.
Very often, traditional smart house systems are driven by small batteries or mains voltage, but there are a lot of disadvantages:
- Battery powered devices are often chosen because they are easy and cheap to install, but the batteries require resources to make and recycly, do not have power enough for example for intelligent and fail safe alarm sensors and they must be replaced fairly frequently if a device is to be expected to work. This can be a problem for example for radiator thermostats, locking systems and access control. Besides, battery leakage can cause bad connections and corrosion.
- Mains driven devices including LED bulbs and chargers include a converter, which
- increases the price and size of the device considerably and may even be a clumsy "brick" on the charging cable,
- require big resources to make and are difficult to recycle due the the use of toxic epoxy boards and big components with the result that the device often just end up as waste in the incinerator or even on the landfill,
- limits the service life of the device considerably - typical to less than half, which makes the waste problem even bigger.
- generates electrical noise and may turn off for a short time in case of transients or voltage drops,
- may even cause a risk of fire and/or shock due to the high voltage levels and often very doubtful quality and cooling,
- often results in a chaos of socket outlets and cable spaghetti on the floor with very low "Woman Acceptance Factor".
- The necessary conversion to and from mains voltage makes it very expensive to utilize a battery and solar panels to save energy, as an inverter system is needed to generate AC. This also significantly reduces the service life and reduces the efficiency at low power level.
A different Sustainable Solution
Max-i offers the ideal solution to all those problems. The high power capability and use of standard installation cables in a "multi-loop plus two tails" structure as shown on the drawing on the top of this page makes it extremely suited as a supplementary 20-Vdc power supply with control possibilities in the houses of the future. It can replace all the point-to-point connections, mains voltage converters and chargers and be used to drive and control not only LED lighting, but also for example window openers and sun shading, computers, tablets and peripherals like screens and modems, low power entertainment systems including TV, low energy refrigerators and freezers, door bells, coupled smoke alarms, burglary alarms and locking systems. In a typical house, such devices use approximately 65 % of the electricity exclusive electric heating, so in case of solar panels, a huge energy saving is possible at a fraction of the cost of a traditional AC system, which is also designed for driving all the high-power devices like stoves, ovens and other kitchen appliances, washers and dryers, vakuum cleaners etc. Calculations done by the Danish engineering company Rambøll shows that such a network can save the Danish households in the order of 1 billion Danish kroner per year corresponding to approximately 134,000,000 Euro or $144,000,000.
In earlier times, when incandescent lamps were used, the power consumption was very large, but only a few resources were used to manufacture and dispose the bulbs. Today it is the other way around. Power consumption is low; but very large resources are spent on manufacturing and disposing of the 230 V converter, so now it is that part that should be focused on and the best solution is simply to avoid them, which is what Max-i does.
The use of 20 V (maximum 5 A per outlet) fits with the maximum level of both USB Power Delivery (USB-C) and Quick Charge from Qualcomm and since the minimum burning voltage of an electrical arc is 18 - 20 V (between copper parts), it is simultaneously the highest voltage, which cannot cause a dangerous arc. At just 28 V, arc lengths up to 12 mm are possible at 50 A and house hold batteries can easily source over 1000 A! Since the charging voltage of a 20-V battery fits very well with the maximum-power-voltage of 54-cell solar panels, such panels may be connected directly by means of a simple Max-i controlled switch as shown on the drawing. The charging current may then be controlled in steps of typical 20 - 180 W depending on the sun light. Since the voltage is always lower than approximately 35 V (open circuit voltage of panels), there is never any shock hazard even in case of fire extinguishing by means og water, which may be very dangerous on traditional serial connected systems.
In sunny areas, it may be possible to drive the devices totally off-grid even in the winter, and the excess power in the summer may then for example be used to drive a ventilation heat pump so that the house gets ventilated and additional heating is not needed most of the year, which can save a lot of energy. The outlet of cold, dry air from the heat pump can even be used for a (supplementary) compressor-less refrigerator to squeeze the last efficiency out of the system and make the household even less vulnerable in crisis situations where refrigeration capacity for food is vital. As the global temperature is rising (AGW) this is especially important in areas, which are often hit by hurricanes. It such situations it is not uncommon that several hundred thousand people are out of electricity in more than one week, which will destroy the food in freezers and refrigerators. The ability to run off-grid (islanding) will therefore become more and more important in the future and with Max-i, it is possible to realize this at a very affordable price and without any shock hazard in case of floods. Even though many traditional photovoltaic systems have batteries, they generate AC for the grid and must therefore have "Grid - Anti-islanding" to prevent that a disconnected grid is powered up and therefore becomes dangerous to the utility workers, so the majority of these cannot run off-grid.
Max-i is also the ideal replacement for the traditional 12-V systems in mountain huts without any grid connection as the higher voltage is better suited for LED lighting and can be used to charge and drive laptop PC's directly. Besides, the multi-drop line is easier to install in a nice way than point-to-point connections between buttons and lamps.
If there is not enough solar power to supply the system in the winter, a grid-powered charger may be necessary as a supplement, but it can be quite small and thus inexpensive as it should only be able to deliver the average power. Besides, it can charge the battery when the grid is low-loaded and/or the share of renewable energy is high and thus both save money and CO2 emissions.
Max-i can be installed and serviced by any electrician and like most other hardware standards like CAN, it does not get obsolete overnight. For smart house applications where there is no problems with mutual coupling to other cables and high current levels are needed, Max-i uses a 5-conductor industrial flat cable with two conductors (1 and 5) for positive voltage (L+), two (3 and 4) for negative voltage (L-) and one (2) for communication (COM), and it uses piercing technic to get contact and make outlets without cutting the cable. If more power is needed than possible with a pure 20-V system, conductor 4 and 5 may instead be used for mains voltage (mains-plus-dimming) as shown below:
Security, Privacy and Safety
Security is of the utmost importance to many people, but it is an area where present technology based on wireless communication and small batteries is almost useless:
- If an alarm system should not give you false security, it must be fail-safe, that is, an alarm is also generated in the absence of a sensor signal - not just as an active signal. If a wire is cut or the system is jammed, an alarm must be generated in less than 1 second, but due to the battery life, it is usually not possible to supervise a device more frequently than approximately once every 10 minutes.
- Battery driven systems only have enough power for simple, low-power sensors such as passive infrared detectors (PID), but these kind of sensors generate many false alarms and may be easy to fool.
- Wireless communication is very easy to jam and may generate false alarms due to other wireless communication in the same frequency band. False alarms and jamming are not only very irritating, but also makes you nervous and it can even be used to force you to switch the system off. A thief just needs to jam the system from time to time to trigger it.
- It can be very difficult to ensure that wireless communication do not disclose information about your home. This is especially a problem with alarm systems with cameras where it is almost imposible to guarantee that your behaviour is never transmitted to third parties or to second parties such as alarm centers when you don't want it. If you even add a cloud based speech recognition system, your privacy is gone forever. Everything you say or do may end up on the wrong places on the internet, and even though it only ought to be the commands to a speech recognition system, which are transmitted, there are people listening to optimize the systems!
- Wireless connection may be used to hack into the system even from a long distance. The safety is not better than the weakest link and the majority of devices are not updated after some time or not at all. Just one unsafe device is enough to open a backdoor into your system on the wrong side of the firewall where there is free access to your other devices and computers.
With Max-i, it is different.
- It has power enough for even the most advanced and fail safe sensors and for driving locking pawls by means of solenoids. Battery powered locks need to use motors, which are slow and need protection against blocking, and may even run out of power.
- It is fast enough to destroy the night vision of a thief by means of powerful light flashes.
- It cannot be jammed unless you get physical access to the cable or an outlet with enabled communication, which should only be possible from alarm monitored areas.
- The Max-i controller (chip) is entirely hardware based and therefore cannot be reprogrammed to anything else than its dedicated purpose so there are no "mousejack" problems etc.
- It is very easy to log all communication to ensure that nothing or nobody transmit unwanted information behind your back. The Max-i controller even has a fairly advanced acceptance filter, which can block telegrams, which would otherwise overload the log-system.
- Unlike for example WiFi, there is virtually no limitations on how many devices you can connect without any noticeable degrade of performance.
- In daily use, you don't need an internet connection, which keeps even the best hacker out. Even when you need it, the connection only goes through one device, which is much easier to keep safety updated.
- It can easily be installed by the user himself just by connecting the sensors to a free outlet, and polling or heartbeat can then ensure that the alarm is triggered, if a sensor is disconnected.
- There is virtually no electromagnetic fields - not even from 50 Hz or 60 Hz solar power inverters.
Simplicity in use.
Max-i may be operated any way you want. Even without a central controller, you may for example control lamps, window openers etc. by means of traditional wall mounted buttons, which is usually the most convenient. In the long run, almost no one bothers to find the right app on a mobile phone every time they just want to turn a lamp on or off. The only difference you will experience with Max-i compared to a traditional system is perhaps a more beautiful touch control with light indication and that you simultaneously get a light dimmer in all lamps with a lot of features like night light and programmable start level, automatic daylight control, all-off (and all-on), synchronized multi-way landing switching and possibility for emergency light with programmable color (need to be reddish in case of smoke). If you connect the bus to a WiFi or Bluetooth interface, you may do the same from mobile phones and tablet and this also makes it possible to set different scenes and control the color hue in case of multi-color lamps. Max-i may of course also be connected to controllers and computers, which can enable more advanced functions like energy management and making the home looks inhabited when you are not at home. It is even possible for an advanced TV to control the light in real time from the image lighting with the same speed and performance as professional stage light.
"Everything should be made as simple as possible, but not simpler."
"Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away."
Antoine de Saint-Exupéry.
.This page is created with WebSite X5 and updated November 12th 2021