The following details information on proposed Hope Container that will be an autonomous, closed loop, off grid system to supply energy, water and food for 50 persons for an indefinite period. The container will be able to be shipped to any place in the world and dependant on the location can be customized to suit the applicable environment and demands.
The following 3 examples detail some of the options available based upon using solar energy to power 2 sterling engines and therefore will be in high sunlight areas, e.g. Portugal, Greece . Other options for energy input e.g. biogas can be used in conjunction or in locations where sunlight energy is less available. However for the following examples solar energy is only being calculated, although renewable storage has been included for overnight usage and several days additional consumption without any sunlight energy required.
The sterling engines for electrical use can use or supply in either DC or AC and therefore as most electrical equipment will be using AC it is suggested to have the DC supply from the solar panels to be converted to AC and the engines to be set to AC input and output. The sterling engines can either produce up to 2kwh or be driven by 2kwh
Total and accurate losses have not been calculated into the complete system as this will be dependant on transmission lines and insulation etc. but an allowance of up to 15% from start to finish should be used as an approximation.
The addition of sun mirror cookers, hot stones and rocket stoves have not been included but these obviously will add to the power availability of the systems.
In all 3 systems it can be calculated that enough energy is available with excess if required, even with all equipment and demand being used.
Example 1 – Water and energy production -> extreme location without any water source
For this system 1 sterling engine in cooling mode will run continuously to produce fresh clean water. Using solar panels of 25m2 a supply of 22.5kwh of electricity will power the sterling engine in cooling mode. This will produce during daylight around 112.5kwh or 4.5K litres of 4deg cooled water which can be fed into water production (condensing water vapour) which will produce around 185 Litres of clean fresh water. An additional option during night time to include excess energy from the second sterling engine would increase this to an additional 127K litres giving a total of 312 litres per 24hours.
The second sterling engine will be powered by vacuum collectors which heat up pressurized water (12 bar) and then fed into a hot oil storage container which will heat up to 230deg. This hot oil storage of 5K litres will store 230kwh of energy. 25kwh of this stored energy will go for cooking ( 5 hours of cooking at 5kwh) and the rest to produce 28.5kwh of electricity. Total usage of electricity is around 13kwh and therefore an excess of 15.5kwh can be supplied to the water producing sterling at night. As this second sterling is producing electricity it will also produce hot water of around 180kwh at 60deg stored in 5K litres which can be used for showering, washing machines and cleaning.
Example 2 – Cooling and energy production – (water available at location)
In this mode one sterling engine will run in cool mode powered again from PV. With a cool storage area of 18.75m3 at 7 deg it will require around 50kwh of cool water at 4 deg stored in 2K litres within the cool storage area thus avoiding losses. This will mean the sterling will require around 10kwh of electricity and therefore the additional 12.5kwh can be offered into the electricity demand.
The second sterling again will be powered from the vacuum tubes heating water and then hot oil to power the engine which after 25kwh of oil has been used for cooking will allow the engine to produce 12.5kwh of electricity (maximum demand around 11kwh) and with the additional 12.5kwh from the PV’s will allow additional electrical energy. The storage of oil in this system will allow for 3 days cooking and 2 days electricity in the absence of sun.
Example 3 – Field testing in Solar Village – water available
In this mode 1 sterling engine will run continuously to produce cooling for food storage at 7 deg. Again the sterling will require around 10kwh from PV’s to produce 50kwh of 4 deg stored water. With a storage of 150kwh of cold water will allow for up to 3 days of cooling energy in the absence of sun. There should be an excess of around 12.5kwh which can be fed into the electrical system or the engine can be run at reduced output.
The 2nd sterling engine will again be powered from the hot oil and produce electricity of around 12.5kwh this is allowing again for around 25kwh of heating oil for cooking.
The variation in this model is that the hot water for showers, cleaning and washing machines will come from vacuum tubes of 30m2 and not from the excess hot water produced from the engine, (although this excess could be fed into the hot water system, or to warm the biogas). As this system will be in the Solar Village it will ensure enough hot water in the case that the sterling is not running continuously. This system allows for stored 3 days cooling, 3 days cooking, 2 days electricity and 3 days hot water in the absence of solar energy.
Power usage for 50 persons data :
Following chart details the various equipment and estimated demand. Whilst some of these figures have come from specification data, others like instantaneous or daily power demand from washing machines and power tools is an indication and demand over the day is using estimated and some Solar village results. At this stage it is not known exactly how many controllers / pumps etc. will be used so we have accounted with an additional 10% requirement. These figures should be updated and refined as more data and testing is available.