[Greenbuilding] Swedish solar-heated village

Don Lush donlush at uniserve.com
Thu Nov 26 11:48:46 CST 2015 

OK- I was interpreting the KW as KW electric not KW thermal.

Don Lush
Bolton Ontario

-----Original Message-----
From: Greenbuilding [mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of John Daglish
Sent: November 26, 2015 10:33 AM
To: Green Building <greenbuilding at lists.bioenergylists.org>
Subject: Re: [Greenbuilding] Swedish solar-heated village

No seems OK efficiency also varies with temperature, though it seems odd the sun is shinning no where else http://en.sat24.com/en

see page 2 a standard flat plate collector  ... collected heat 45% http://www.lth.se/fileadmin/ht/Kurser/MVK160/Project_08/Fabio.pdf

The Sunmark collector includes anti-reflective glass and some models a transparent anti-convection current screen between the glass and absorber reducing heat loss through the glazing.

There is a 4000m3 of hot water storage at Sønderborg http://www.sonderborg-fjernvarme.dk/wp-content/uploads/2013/06/Solparken_folder_gb.pdf

Expected share of solar heat in total annual plant production is 20%

John Daglish
Paris, France


2015-11-26 14:43 GMT+01:00 Don Lush <donlush at uniserve.com>:
> Thanks John (Daglish)- Could you help me on the interpretation of this interpret this data.
>
> For example when I look at the current data (8:30 EST) from Sondorborg 
> it shows current insolation at 939 W/m2 (which I am assuming is the 
> incident solar radiation energy currently hitting the earth's surface at this location??) It then shows current solar production at 442 W/m2 (which I assume is supposed to be how much energy is being generated by the solar array per m2.) This implies a conversion efficiency of (442/939) 47% which is incredibly high!
> Other sites have zero insolation and negative production numbers implying that they are consuming power.
> How am I misreading this?
>  Don Lush
> Bolton Ontario
>
> -----Original Message-----
> From: Greenbuilding 
> [mailto:greenbuilding-bounces at lists.bioenergylists.org] On Behalf Of 
> John Daglish
> Sent: November 26, 2015 6:58 AM
> To: Green Building <greenbuilding at lists.bioenergylists.org>
> Subject: Re: [Greenbuilding] Swedish solar-heated village
>
> Our Dannish friends are way ahead...
>
> Smart Energy Systems: 100% Renewable Energy at a National Level (Short 
> Version) https://www.youtube.com/watch?v=S1P31EC0YsE
>
> Smart Energy Systems: 100% Renewable Energy at a National Level (Full 
> Version) https://www.youtube.com/watch?v=eiBiB4DaYOM
>
> Solar heat fields for district heating   - real time production
> statistics, not much today its cloudy
> http://www.solvarmedata.dk/
>
> regards
>
> John Daglish
> Paris, France
>
>
>
>
> John Daglish
> Paris, France
>
>
> 2015-11-25 21:11 GMT+01:00 Dan Johnson <danjoh99 at gmail.com>:
>> It's great to see Nick Pine back on this list. I want to point out 
>> for discussion that the electrical grid has virtually no storage! The 
>> grid follows load and must be balanced nearly instantaneously with 
>> dispatchable generation.
>>
>> Contributing PV energy to the grid is often part of the problem, 
>> because renewables often need to be curtailed when production exceeds 
>> demand. Grid operators can't taper down the baseload generators every 
>> time the wind picks up. The California ISO site has a lot of current 
>> information and I've found it a great place to learn about the 
>> electrical grid. And this is one of the most progressive operators in 
>> terms of their renewables and storage mandates from the State.
>> http://www.caiso.com/Pages/default.aspx
>>
>> Bringing this back to solar storage in winter (in California, for 
>> example), when I do morning warm-up or heat during a cloudy day using 
>> my electric heat-pump, the electric grid is running natural-gas-fired 
>> generators at an emissions rate that is dirtier than average. This is 
>> because renewables are generally not online during these periods.
>> Check out this net-demand chart from Cal ISO: the morning peak of the 
>> green line is all fossil fuel, before solar comes online.
>> http://content.caiso.com/outlook/SP/duck.gif. There may be less 
>> emissions and less fuel burned if I just burned the natural gas at my 
>> house with a condensing appliance, as a backup to my passive systems, using no storage. The chemical bonds in the natural gas provide the storage.
>> :-)
>>
>> Any net surplus of PV from my house would occur when I don't need it 
>> to power a heat-pump or A/C: these are periods when likely other 
>> houses don't need it either. Net consumers would be commercial 
>> buildings, hospitals, and other process loads on the grid. In one 
>> scenario, we can ramp-down the fossil generators during these 
>> periods, so **here is where we can argue that the homeowner's PV 
>> could be considered a carbon offset**---but no more real than Terrapass.
>> http://www.terrapass.com/. In another scenario, the added power from 
>> renewables just lets us bring more loads online---total load and demand grow over time! This is the opposite of what we wanted.
>>
>> Returning to grid-scale storage: it seems this is science fiction, 
>> like clean coal. Euan Mearns has some great analysis of experimental 
>> pumped hydro schemes in the Canary Islands.
>> http://euanmearns.com/el-hierro-another-model-for-a-sustainable-energy-future/.
>> California conducted a workshop in Jan 2014 on pumped storage and 
>> many presentations from it are here:
>> http://www.cpuc.ca.gov/PUC/energy/electric/Technical_Workshop_Understanding_Current_State_of_Pumped_Storage.htm.
>> If 300 high reservoirs were built along the coast, using the ocean as 
>> the low reservoir, the grid could get 572 GWh of storage, almost 1 
>> day of storage for California!
>> http://www.cpuc.ca.gov/NR/rdonlyres/1521FE3B-2FB5-4A6A-A93B-45125D6EF
>> 8 95/0/Barnhart20140116CPUCPHSWorkshop.pdf
>>
>> Best,
>> Dan Johnson
>> Albany, CA
>>
>> On Tue, Nov 17, 2015 at 12:06 PM, Nick Pine <nick_pine at verizon.net> wrote:
>>>
>>> Kimmo writes:
>>>
>>>> I’m an entrepreneur that is doing research the possibility to use 
>>>> some architecture ideas to heat houses in Sweden similar
>>>
>>> to what Soldiers Grove did back in 1979. We will of-course try to 
>>> modernise the design but the basic concepts are the same with the 
>>> “solar attic”.
>>>
>>> Soldier’s Grove attics required moving warm air down to the lower 
>>> part of the building using fans or blowers and a motorized damper, 
>>> and it’s hard to store solar heat from warm air. I figure cloudy 
>>> days are like coin flips, so a building that can store enough heat 
>>> for 1 cloudy day can be at most 50% solar heated, with a possible 
>>> max 1-2^-N solar heating fraction if it can store enough solar heat 
>>> for N cloudy days in a row, eg 1-2^-5 = 0.97 with 5 days of storage. 
>>> Most of the SG buildings were only 50% solar heated. Why stop there?
>>>
>>> It seems to me that collecting enough heat to warm a building on an 
>>> average day would be simpler with some passive solar heaters built 
>>> into the south wall, eg 
>>> http://www.builditsolar.com/Projects/SpaceHeating/solar_barn_project.
>>> htm
>>>
>>> Where I live near Philadelphia, PA, 1000 Btu/ft^2 of sun falls on a 
>>> south wall on an average 30 F January day, so a 4 foot x 8 foot 
>>> vertical south air heater with US R2 twinwall polycarbonate glazing 
>>> with 80% solar transmission would gain 0.8x32ft^2x1000 = 25.6K 
>>> Btu/day. With a 70 F building and a T (F) exit air heater temp and a
>>> (70+T)/2 average air temp inside the heater and a 6-hour solar 
>>> collection day, the heater would lose about
>>> 6h((70+T)/2-30)32ft^2/R2 = 48T+480 Btu/day. With a constant C cfm 
>>> airflow, the collector would provide 6C(T-70) Btu/day of heat to the 
>>> building... 2 1
>>> ft^2 vents with one-way plastic film flappers and an H = 8 foot 
>>> height difference would make C = 16.6x1ft^2sqrt(8'(T+70)/2-70)) =
>>> 33.2sqrt(T-70) cfm, and 25.6K = 48T + 480 + 200(T-70)^1.5 makes 543 
>>> = T + 4.15(T-70)^1.5, ie T = 70+((543-T)/4.15)^(2/3). Plugging in T 
>>> =
>>> 100 on the right makes T =
>>> 92.4 on the left, then 92.7, then 92.7, with C = 158 cfm and a
>>> 6x158(92.7-70) = 21.5K Btu/day heat gain for the building, which 
>>> might have just enough thermal mass and insulation and airtightness 
>>> to cool from 70 to
>>> 60 F by dawn... 60 = 30+(70-30)e^(-18h/RC) makes RC =
>>> -18h/ln((60-30)/(70-30)) = 63 hours.
>>>
>>> And given the present low cost of PVs and inverters, we might heat 
>>> the building with Mitsubishi or Fujitsu mini-split heat pumps on 
>>> cloudy days (they work with an outdoor air temp down to minus 13 F), 
>>> powered by PVs, using the electrical grid for storage instead of a
>>> 5000 gallon hot water tank. How many peak watts of PV would be 
>>> required for space heating alone, with a COP of 3? A simulation 
>>> using hourly EPW weather data could help estimate this.
>>> http://apps1.eere.energy.gov/buildings/energyplus/cfm/weather_data3.
>>> c fm/region=6_europe_wmo_region_6/country=SWE/cname=Sweden
>>>
>>> Then again, a solar village could have passive solar air heaters on 
>>> each house and a large common underground heat storage tank with a 
>>> geodesic transparent roof and a simple drainback hydronic collector 
>>> on top of a floating insulated cover under the roof.
>>>
>>> Nick
>>>
>>>
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