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#76 2019-09-28 03:01:03

louis
Member
From: UK
Registered: 2008-03-24
Posts: 4,924

Re: Ultra thin PV film

Solar power does require a different attitude to energy expenditure. It would make sense to heat water during the day and keep it well insulated. It will make sense to use washing machines, dish washers and the like during the day. It will make sense to charge up laptops and rover batteries during the day, as far as possible. 

I don't think for Mission One there would be any need for tricky energy storage solutions like heated salts. A combination of chemical batteries and methane-oxygen manufacture should suffice.


Calliban wrote:
SpaceNut wrote:

The 10 kw systems that nasa is developing is being design to not melt down and needs no coolant as its self contained with I think salts for the means to radiate heat.

Its the battery capacity that allows for the higher currents as the panels are low current devices. You would use extra batteries to lower the current draw on each to keep them from over heating when under the higher current useages.

That would be a backup system for using surplus methane and oxygen for power and I think its a last resort to out last a dust storm should the sun be totally blocked out for a long period of time. At that time we would be in emergency power useage protocal so as to conserve energy.

Got it.  That makes more sense.  One could in fact use one of the vehicles to generate small amounts of emergency power from the alternator.

The Martian surface has huge day-night temperature variations.  If we could makes solar thermal panels from local materials, it should be possible to store heat and cold from day and night respectively, in tanks of fluid or masses of soil and rock.  A sterling engine could run between the hot a cold stores, generating constant power across the day night cycle.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#77 2019-09-28 15:47:58

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,181

Re: Ultra thin PV film

https://www.tesla.com/support/powerwall … -an-outage
A useful tool if you know what will be on and how long it will be used to calculate when the powerpack will run out of juice.

Power attributes of the battery is power at fully charge -minus discharge power levels knowing that the current is not rising with the decaying voltage will be the whr that we can use. The time of the capacity is relative to the ampere hour rating of the battery.

As the 2400kwhr battery for a landed ship comparison since I am sure they will be based on the power wall 10kwhr and Tesla Model 3 battery pack sized at 80.5 kWh....

A level 1 charger is a slow charger that will take 8-15 hours to charge your car.
A level 2 charger is a 6 kWh charger that is also pretty slow if you're used to Supercharging—it will take 3-8 hours to charge your car.
With the danger of fast charge near the 3hr time we will be causing internal damage which will kill the battery from the internal heat of charging.
simple math of 8 hr x 6kwhr of charge means we will be at 48 kwhr capacity from the discharged voltage

Mars like earth has a solar charge output of 3 5 hours where the current coming out of the panels rise to the 70% voltage level under load for that time period and below that we are not charging as the voltage is to low under load currents.

That said in the morning until it reaches the 70% point to charge we will use 2 panels in series to boost the voltage to the charger input. At the 70 % and up we then change the panels interconnections to parallel and the back to series once it get below the 70% some period of time later to get the most of the panels collected power to batteries.


Earth panel input power 1,000w would get 300 w to 400 w panels but the same panel of mars only gets 430 watts input to produce power 129w - 172w for the panel

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#78 2019-09-30 17:32:38

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 16,181

Re: Ultra thin PV film

Design Methodology of Off-Grid PV Solar Powered System
http://castle.eiu.edu/energy/Design%20M … 1_2018.pdf

Design of an off-grid Photovoltaic system With supplementing energy from Wind and Diesel
https://scholar.harvard.edu/files/amade … f-grid.pdf

Scaling up of off-grid Solar Micro grids
Moving towards a "utility in a box" model for rapid deployment
https://static1.squarespace.com/static/ … _Anjal.pdf


Solar Bench
http://acep.uaf.edu/media/260463/EEM-01 … 201805.pdf

A Solar Design Manual for Alaska
https://www.evansville.edu/majors/eecs/ … Report.pdf

Something to note in the Alaskan use is the tracking of panels to maximize the power out of them and when its not they are setting them for the season angle and using a 3 set setup with panels set so as to get the max levels through part of the day for each set.

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