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That wouldn't work for much of the South where summer usage for a house can easily hit 100 kWh/day for air conditioning. The hottest part of the day usually sta
by merpnderp 9y ago
That wouldn't work for much of the South where summer usage for a house can easily hit 100 kWh/day for air conditioning. The hottest part of the day usually starts at about the end of the prime solar hours. Plus you'll want massive overcapacity of your batteries as deep discharges drastically reduce their useful lifespan.
- skummetmaelk 9y ago100 kWh/day is just incredible. The average consumption per person in the nordics is about 1500 kWh per YEAR.
- blacksmith_tb 9y agoI would have thought that heating would require a lot of energy in the Nordic countries - but perhaps that doesn't use much electricity? I live in the NW US, in a heavily-insulated passivhaus with a 5kW PV array on my roof, and my average usage is 13kWh / day (though I am also charging a PHEV vehicle's battery some days, and still using an ineffecient old hex-core Xeon workstation on top of heating and cooling, heating water, cooking etc.).
- skummetmaelk 9y agoElectrical heating is not used when it can be avoided. It is much better to use waste heat from energy production and industry to heat your home: https://en.wikipedia.org/wiki/District_heating https://en.wikipedia.org/wiki/District_heating
- zAy0LfpBZLC8mAC 9y agoActually, in Norway most of the heating is done with electricity (they have loads of hydro power).
- baybal2 9y agoI believe, they don't use electricity to heat the house in -20C, and few live in detouched houses.
- zip1234 9y agoMost likely not using electricity for heating/cooling?
- pjc50 9y agoThat doesn't quite seem right: http://shrinkthatfootprint.com/average-household-electricity-consumption http://shrinkthatfootprint.com/average-household-electricity... (Interestingly Canada's per capita consumption is comparable to the US despite being much further north)
- skummetmaelk 9y agoI should have edited my post to say just Denmark. Sweden and particularly Norway use much more energy.
- Gravityloss 9y agoIf it's 10 cents per kWh, that's only 10 dollars per day or 300 per month. Investing in insulation or other things might or might not make sense. High electricity price for a long future period would also encourage investment. Alternatively, constructing your house in a benign climate, if you do a lifecycle analysis and look at the upkeep cost.
- zAy0LfpBZLC8mAC 9y agoI would think that for that use case, using thermal storage should be more efficient? Don't store electricity to run AC later, but run AC to cool down water or the ground beneath your house or something, and then cool your house with that later.
- cobookman 9y agoOr build something like an Earthship (http://earthship.com/ http://earthship.com/). I know that these can air condition a house in New Mexico through geothermal heat transfer, however no idea how they handle the more humid summers of the South East.
- yourapostasy 9y agoThey work, but aren't as comfortable as in drier climes. Humidity is tough to control with low-energy, low-maintenance solutions. Unfortunately, many people's discomfort perceptions are heavily influenced by humidity.
- biomcgary 9y agoI recently moved from Nashville (quite humid) to Flagstaff (quite dry) and the difference is amazing. Large temperature swings are barely noticeable in the dry climate, but would require substantial changes in weight of clothing in the humid one.
- djrogers 9y agoThat would require a huge amount of work and expense, and at the end of the day cold water isn’t very good at cooling off giant masses of air and furniture.
- maxerickson 9y agoThey are sized for bigger installations, but time shifting energy consumption using ice storage is basically an available commercial product. Here's one company that makes them. http://www.calmac.com/ http://www.calmac.com/
- EngineerBetter 9y agoWow - that's a crazy amount of energy. As a Brit who's never been the south of the US, is that figure really true? 100kWh is about 300 miles in a Tesla, or boiling a kettle constantly for about 30 hours. If that's really accurate, then I'm staggered at how much energy folks must be using to keep cool, and makes my efforts at saving energy seem paltry in comparison.
- 2sk21 9y agoI live in New Jersey and just had solar panels installed on my roof. Peak power is about 7.8 KW. On clear days, power production in the summer is about 50 kWh I have been keeping daily logs this summer and find that my daily power consumption swings between about 25 kWh on cool days to 65 kWh on really warm days. Definitely a lot lower than 100 kWh mentioned previously.
- jessriedel 9y agoNeedless to say, NJ is very different the South, and in any case this is highly dependent on the size of the house and the amount of insulation.
- lossolo 9y agoIt's 24/7 air conditioning working. In EU you get around 100kWh per day also if you use home air condition 24/7.
- OtterCoder 9y agoRemember, the south of the US is in the subtropics, roughly level with the north of Africa. Imagine living in Egypt and not running the AC constantly.
- widdershins 9y agoThere are a lot of people living in Egypt who don't have to imagine that.
- 9y ago
- sp332 9y agoIt's only prime solar hours if you point your solar panels due south. That gets you a higher figure on paper, but if you need the power later in the day you could point them a bit more to the west and get a lot more usable power when you need it. With solar panel prices falling, it's a race to see if it's cheaper to over-provision solar panels or batteries.
- beefield 9y ago> deep discharges drastically reduce their useful lifespan. That applies to lead acid batteries. Lithium ones are much more forgiving on that (as long as you stay within design limits.)
- kilroy123 9y agoThere are far cheaper ways to keep your house cool, though they require an upfront investment. http://energyblog.nationalgeographic.com/2013/09/17/10-myths-about-geothermal-heating-and-cooling/ http://energyblog.nationalgeographic.com/2013/09/17/10-myths...
- baybal2 9y agoThis digit is unbelievable. A good aircon can pump 4 gigacalories per hour using 1kw/h while running at full power with +40C and 40% humidity outside. 5gkal per hour is more than enough to keep a 50m2 room with huge windows at 21-22C in scorching heat. If your house is huge, like 200m2 McMansion, and your ventilation does no recuperation whatsoever, and you have near nil heat insulation (like most of housing in US,) you will barely use 50kw/h per day even if you live in the middle of Sahara
- zip1234 9y ago200m2 is about 2/3 of the area of what a McMansion would be. Many are twice that.
- zip1234 9y agoEven if the hottest part of the day is past prime solar hours, with a solar system you won't be discharging the battery as fast since the system will be powering the AC for most the day. Also, with that much usage, it might be time to investigate insulation.
- Florin_Andrei 9y ago> That wouldn't work for much of the South where summer usage for a house can easily hit 100 kWh/day for air conditioning. It should be noted that peak energy expenditure for air conditioning happens more or less at exactly the moment when the influx of energy from the Sun is also at its peak. That's, like, a gigantic hint that mother nature is dropping on you, hoping you'll notice it. The disease, and its cure, are gushing forth from the same place at the same time. Probably most of the energy for air conditioning in the future will not come out of storage, but it would be produced at the moment when it's consumed, by solar panels or some other solar technology.
- clock_tower 9y agoFrom the grandparent's post: > "The hottest part of the day usually starts at about the end of the prime solar hours."
- jamestnz 9y agoFor those interested in more info on this, it's called Temperature Lag. There's also the related phenomenon of Seasonal Lag, which is where the hottest part of the year comes somewhat after the period of maximum solar radiation, not during it. https://en.wikipedia.org/wiki/Diurnal_temperature_variation#Temperature_lag https://en.wikipedia.org/wiki/Diurnal_temperature_variation#... https://en.wikipedia.org/wiki/Seasonal_lag https://en.wikipedia.org/wiki/Seasonal_lag
- Florin_Andrei 9y agoThere's still significant overlap, it should be used.
- usrusr 9y agoA well insulated water tank that is electrically chilled during peak solar and used to cool down air later in the day/night could solve that storage problem without any cell degradation. Theoretically, with perfect insulation, this could even reduce the total electricity demand, when the conversion from electricity to a temperature gradient happens during a time when the base temperature is low.