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1.8 Billion Homes Powered by Renewable Energy

100% full-time solar off-grid living, designed for completely sustainable rooftop solar or renewable grid electrification.

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1.8 billion homes can be powered by renewable energy, which will reduce power outages, CO2 emissions, and living costs, by adding all the global solar, hydroelectric, and wind energy produced in 2022 (7700TWh) then dividing that by the energy consumed yearly by a single resident in the Solarcycle designed tiny home (4.16MWh):

https://www.iea.org/energy-system/renewables/solar-pv
https://www.iea.org/energy-system/renewables/hydroelectricity
https://www.iea.org/energy-system/renewables/wind

100% Off-Grid Solar Power is achieved by combining the latest energy efficient products on the market and balancing power loads. This is accomplished by designing a tiny home that enables maximum solar energy generation and storage in a limited space, then matching that to the total energy consumption of a single residential occupant. This energy value is calculated to be around 80kWh per week per person, which can be supplied by rooftop solar or connected to a renewable energy powered grid.

* Days Powered Without Sun: 1 Day @ Max Load | 5 Days @ Min Load

* Typical Recharge Time From Empty to Full: 3 Days of Full Sun

* 24 Foot Trailer * Sleeping Loft * About 248 Square Feet Total

* 7 X 410 Watt Solar Panels | 2872 Max Watts Total

* Can Produce 545 Watts even on a cloudy day

* 44kWh Battery Rack @ 48 Volts

* Max Continuous Load : 15kW @ 120VAC

* Average Hours of Sun Per Day Required for Max Load: 4.6 hours

* RV Water Connection and 8 Gal Point-of-Use Water Heater

* Inductive Stove Top with Range Hood and 4-in-1 microwave/oven

* 32" Shower and Choice of Toilet Style

* Generator/Grid Tie Input: Standard 50 Amp Connection

* Power Output: Standard 50 Amp Socket

Design challenges include supply chain issues, certifications, scaling up production, and cost of materials due to inflation. Plans for deployment include setting up a tiny home factory and maintaining quality control standards.

Interestingly, this value 80kWh per week (4.16MWh per year) for a person living in this tiny home seems to match what a typical person consumes from their existing power company and you can check your electric bill to see if your weekly power consumption is the same. Simply take the average monthly electric consumption and divide it by 4 weeks then divide by the number of adults living in the household. This is very close to the average per capita electricity consumption in the UK: https://www.statista.com/statistics/383633/worldwide-consumption-of-electricity-by-country/

This is a conservative estimate since this does not account for multiple occupants in the tiny home, time away from home, the newer generation of solar power equipment, or other renewable sources of power like farm animals, passive geothermal, and biogas, which significantly increases energy efficiency in the future.

Assuming the toilet is connected to a sewage, septic, or composting system, the top five most power consuming appliances are the water heater, space heater/air conditioner, the solar inverter itself, refrigerator, and a hair dryer.

Since the water heater consumes more than double the energy of the second most power hungry appliance, the water heater is the target of the most energy efficient design possible using the latest technology available. The final water heater design utilizes the smallest 8-gallon water heater tank with the highest operating temperature of 161 F then installing a thermostatic valve on the outlet, which automatically mixes with cold water to bring the temperature down to a safe 120 F. A smaller hot water tank at a higher temperature is much easier to store, insulate, and heat up with a smaller heating element over a longer period of time than a larger tank at a lower temperature. Combined with a lower flow shower head of less than 2GPM, a maximum shower time of 13 minutes can be achieved with only 8 gallons of hot water. This is a good online hot water mixing flow calculator: https://www.spiraxsarco.com/resources-and-design-tools/calculators/water-mixing/water-mixing

It is also interesting to note that the size of the battery required for 100% solar off-grid is about the same size as an electric vehicle battery. The difference is that the house battery can provide energy for cooking, showers, heating, air conditioning, lighting, working from home, food storage, washing clothes, entertainment, and powering electronics while the car battery energy is mostly used for pushing a 2,000 pound piece of metal on wheels around town. In comparison, a full high speed rail service in California would require 5.16TWh of electricity a year, which would be equal to over 1.2 million electric vehicles assuming similar battery capacity and discharge cycling as a tiny home. 

https://hsr.ca.gov/wp-content/uploads/2022/09/final_EIR_MerFres_TA3_06C_EnergyUse-A11Y.pdf

In another comparison, the electric energy consumption of Bitcoin fluctuates with the price, but even in a bearish market low estimate...

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TINY HOME ELECTRICAL.pptx

presentation - 59.98 kB - 09/25/2023 at 04:09

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Solarcycle Tiny Home Prototype FRAME.stp

Prototype bare frame, trailer, straps, and tie downs

stp - 2.87 MB - 09/25/2023 at 04:06

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Solarcycle Tiny Home Prototype.stp

Prototype complete assembly

stp - 14.72 MB - 09/25/2023 at 04:06

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SOLARCYCLE ONE TINY HOME REV F.pdf

Final Design Version for an improved future build.

Adobe Portable Document Format - 955.32 kB - 08/06/2023 at 16:53

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Solarcycle Tiny Home Energy Calculation Spreadsheet.xlsx

sheet - 18.88 kB - 08/06/2023 at 16:53

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  • 1 × Ariston Water Heater ANDRIS RS 8U 1.4KW Point-of-Use Water Heater 8 Gal
  • 1 × SharkBite Thermostatic Mixing Valve 24505 3/4 in Thermostatic Valve
  • 1 × Thermostatic Shower Valve MISSMIN 4 inch
  • 1 × Oxygenics Low Flow Shower Head CareSpa 1.8GPM
  • 1 × Glass Heater HS-1648-V8 500-Watt Radiant Wall

View all 33 components

  • Solarcycle Tiny Home Hot Water Heater Test Complete!

    isaacporras09/25/2023 at 14:58 0 comments

    Solarcycle tiny home hot water heater test video now available and submitted to Hackaday Prize 2023! Results show over 5 minutes of a hot water shower with just a 2.5 gallon water heater! I am confident that this can be scaled up to provide at least 13 minutes of a hot water shower with only an 8 gallon hot water heater. https://youtu.be/4YaqlGCZgIk?si=1Z3Dy9BzkoOHc6OF

  • Highest Power Consuming Components

    isaacporras08/14/2023 at 04:22 0 comments

    I added the top 4 most power consuming products in the tiny home to the Components List, which include the water heater, wall heater, the solar inverter, and refrigerator. Out of these 4 components, the water heater system will be main the focus of this custom energy efficient design because the water heater system can be modified to improve efficiency by using a thermostatic valve and adjusting temperature settings.

View all 2 project logs

  • 1
    Acquire the tiny home trailer

    The first step of any tiny home on wheels build is to acquire the tiny home trailer. It doesn't really matter the exact type of trailer, but it should have tiny home specific features built-in like leveling jacks, thick structural frame steel to bolt to, and room for subfloor insulation. Many tiny home trailers include instructions on how to construct the subfloor and secure the wall bottom plates, so at the start of construction the trailer manufacturer's instructions can be used. The maximum trailer width is 8 feet for moving on the road without special permits. The the final design for this project is a 24' trailer, but a 20' trailer is currently being used for the prototype.

  • 2
    Frame the Tiny Home Structure

    Please refer to the Assembly Drawing PDF file in the attached documents for detailed manufacturing dimensions and bill of materials. Again, this prototype version is a smaller 20 foot long tiny home, so the drawings can be used as a guide that can be scaled and modified for any other particular size or other design. Keep in mind that the maximum legal height for a tiny home on wheels is 13-1/2 feet, so make sure that the final design does NOT exceed this height, which includes any roofing material. If the frame and rafter structure is at least a few inches under the maximum height limit, it should meet the height requirement once all the final exterior layers are added. Be sure to follow manufacturer instructions for all doors, windows, siding, and metal roofing especially the flashing and water barriers. I recommend using ice/water shield rolls on the roof sheathing. One tip I learned is to use flexible window adhesive flashing around the exterior wheel well where rain can pool and leak in to the interior space. From this prototype build, I came to the conclusion that multiple roof angles and an overhang over the trailer tongue added extra build difficulty, less space for solar panels, and not much extra loft space, so this was removed from the final design to save time and cost. Storm doors are also highly recommended since most doors are not designed to have rain directly hitting them, which can pool water and cause moisture buildup around the door interior. Also, here's some good videos on wall framing basics:

  • 3
    Install Solar Electrical

    After framing and finishing the tiny home exterior, installing the electrical is next. This prototype has 690W Solar Output with a 180Ah 24V LiFePo4 battery, Midnite Solar charge controller, and 4kW 240V center tapped inverter. Here are the settings for the Charge Controller after tuning it with the help of tech support:

    Equalize = Absorb, Absorb 28V, Float 26.9V

    Absorb time 30 mins, Equalize time 0 mins

    Ending Amps 9, Rebulk 26.0V, Skip 0 Days

    Output 90A, Min T-Comp 9.9V, Max 29.2V

    VBatt Offset 0.1V, Vpv 0.8V

    Follow manufacturer's instructions and electrical code for installing solar panel rack system, and other electrical components. The battery was installed above the back door with a heavy duty reinforced shelf and a lot of the wires were hidden inside the wall, but the final version will have the battery on a rack on the floor with wires inside cable trays for easier installation and serviceability.

    I did decide to ground the entire trailer to the main panel by connecting a 6 gage copper wire to one of the frame bolted holdowns with nuts and washers for extra safety. Once the main panel was installed, the sub panel with two breakers were installed and typical 120V AC wiring was done throughout the house. The 240V inverter has two separate 120V hot wires connected to a shared Neutral. I separated the two 120V hot wire with two circuit breakers in the subpanel and I divided them by lights, fans, refrigerator on one breaker while the air conditioner or hair dryer is on the other breaker. Basically, the breakers were divided by lower power consuming appliances that need to be on most of the time and other higher power consuming appliances that are on for shorter periods of time so that they don't trip a breaker.

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Discussions

isaacporras wrote 08/15/2023 at 00:40 point

Yes, I have looked into heat pump water heaters and it is a great technology. However, I haven't seen any heat pump water heaters that are near the size of the small point-of-use water heaters that can easily fit in a tiny home. Also, the heat pump water heaters tend to use 240V, which can be used, but I found that load balancing on a space limited solar power system works way better with a lower power water heating element set to a higher temperature setting over a longer period of time than a high power water heater for a shorter time. Of course more solar panels and batteries can power more powerful equipment, but the goal of this project is to actually determine the minimum energy requirement of life that doesn't sacrifice quality and may actually work better than a normal apartment.

  Are you sure? yes | no

Ken Yap wrote 08/14/2023 at 04:30 point

Is there not a heat pump water heater suitable for your design in place of a resistive heater?

  Are you sure? yes | no

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