Grid-tied solar

[BobRip]

I have excellent location for such thing. Systems like that are used on large scale all over the world. Many in the USA. But systems alike that are relatively complex, expensive and require maintenance.

I have another idea. We AC and heat our house with geothermal heat pump. It would be quite easy to install large tank that could be heated or cooled when the sun is shining and the used the accumulated energy to heat the house. Similarly when the tank is cold I could sink energy in when AC is in operation. Only problem is that the heat pump uses only 4.5kW but my peak excess might be even three times as large. Right now I am working the numbers before I put the effort in building it.

You could over heat/cool your home by a few degrees when you have solar. You could heat your hot water a little more when you have solar. You could charge up your well when you have solar. Same with clothes dryer. Just some thoughts. Edit you could run a dehumidifier in the summer also.

 

[Redneck in training]

You could over heat/cool your home by a few degrees when you have solar. You could heat your hot water a little more when you have solar. You could charge up your well when you have solar. Same with clothes dryer. Just some thoughts. Edit you could run a dehumidifier in the summer also.

That is exactly what I am doing. The problem is that I can sink only 4.5 kW of energy by the heat pump while I have 10kW or more excess.

 

[dave1949]

That is exactly what I am doing. The problem is that I can sink only 4.5 kW of energy by the heat pump while I have 10kW or more excess.

I think the electric vehicle is a good solution. There are ideas about dynamically integrating an electric vehicle's stored power into a home's electrical system.

With modern, low-cost programmable electronics it would be possible to have a home energy management system capable of scenarios such as that.

For example, if a cloud interrupts your solar output and the e-car is present with some minimal charge on board, take power from the e-car battery, not the grid. Smart appliances could also react to the amount of power available by delaying or reducing operation.

There is a whole world of technology out there that we have yet to apply to energy conservation.

 

[houstonscott]

It is stated the electric vehicle is a solution. Solution to what?


HS

 

[Redneck in training]

I think the electric vehicle is a good solution. There are ideas about dynamically integrating an electric vehicle's stored power into a home's electrical system.

With modern, low-cost programmable electronics it would be possible to have a home energy management system capable of scenarios such as that.

For example, if a cloud interrupts your solar output and the e-car is present with some minimal charge on board, take power from the e-car battery, not the grid. Smart appliances could also react to the amount of power available by delaying or reducing operation.

There is a whole world of technology out there that we have yet to apply to energy conservation.

I think systems like that are in development already. Following the development in general it looks like reliable long lasting storage energy is only few years away. Several developers of Ultra capacitors claim they have storage devices close to moving from the lab to production.
Ultra capacitors can sink full charge in seconds (if such source could be available) and can be discharged million times to zero. In other words hey should last forever.

 

[BobRip]

That is exactly what I am doing. The problem is that I can sink only 4.5 kW of energy by the heat pump while I have 10kW or more excess.

You could run electric heaters. Just some portable heaters that run about 1500 watts. Three of those would use 4500 watts. These are terribly inefficient compared to your heat pump, but the energy is wasted otherwise. You could also install some permanent base board heaters. There are also energy storage heaters that I have seen in Germany. They are insulated with a heat storage medium inside. A fan is turned on to circulate the heat into the house when needed. When the fan does not run the heat pretty much stays inside.

 

[BobRip]

I think systems like that are in development already. Following the development in general it looks like reliable long lasting storage energy is only few years away. Several developers of Ultra capacitors claim they have storage devices close to moving from the lab to production.
Ultra capacitors can sink full charge in seconds (if such source could be available) and can be discharged million times to zero. In other words hey should last forever.

Present ultra capacitors have very low energy density. Much lower than batteries, which are much lower than gasoline. Do you have information that the new ones will be much much better.

 

[Redneck in training]

You could run electric heaters. Just some portable heaters that run about 1500 watts. Three of those would use 4500 watts. These are terribly inefficient compared to your heat pump, but the energy is wasted otherwise. You could also install some permanent base board heaters. There are also energy storage heaters that I have seen in Germany. They are insulated with a heat storage medium inside. A fan is turned on to circulate the heat into the house when needed. When the fan does not run the heat pretty much stays inside.

We have floor heating. Also our AC uses liquid to circulate in the fan coil. I can use liquid as energy storage in heating season or heat sink in AC season. I just need to develop some device (PLC based I suppose) that would match the load to the excess in the heating season. I am retiring in about 6-8 months. It will be one of my early retirement projects.

I am very familiar with the storage heaters from Europe. There are bricks inside arranged so there air passages. It is charged at night at low rate and could supply heat for about 6 hours when needed. There were also some with some kind of salt that was melted. Those would supply more or less constant heat until the salt solidified.

 

[BobRip]

We have floor heating. Also our AC uses liquid to circulate in the fan coil. I can use liquid as energy storage in heating season or heat sink in AC season. I just need to develop some device (PLC based I suppose) that would match the load to the excess in the heating season. I am retiring in about 6-8 months. It will be one of my early retirement projects.

I am very familiar with the storage heaters from Europe. There are bricks inside arranged so there air passages. It is charged at night at low rate and could supply heat for about 6 hours when needed. There were also some with some kind of salt that was melted. Those would supply more or less constant heat until the salt solidified.

Yes, that's it. I had a friend in Germany who had those. It sounds like you have a good understanding of all of this.

 

[Scooby074]

Electrical Thermal Storage heaters are real common here. We have both peak and off peak rates . People "charge" them up off-peak then use the heat during peak hours.

Save on Heating With Electric Thermal storage heating (ETS) Systems

 

[dave1949]

Some news on PV efficiency improvements for industrial concentrating collectors achieved by stacking multiple cells. The "number of suns" is the number of reflectors concentrating the sun on the individual collector cells.

44.7% at 297 suns:
World record solar cell with 44.7% efficiency

New connection between stacked solar cells can handle energy of 70,000 suns

 

[dave1949]

The September, 2013 results.

Down 5 kWh from Sept. a year ago, but 82 kWh AC above the model.

That doesn't surprise me as we have had an unbelievable stretch of clear weather this month. I took the reading at noon, so we likely exceeded last year by a bit. Our daily production now is ~25 kWh on these clear days.

Month--NREL Model (AC kWh)-----2012 Actual-----2013 Actual

Jan.----388----------------------NA--------------440
Feb.----412----------------------NA--------------375
Mar.----509----------------------NA--------------462
Apr.----374----------------------NA--------------487
May----353----------------------NA--------------375
Jun.----308----------------------NA--------------379
Jul.-----341----------------------NA--------------377
Aug.----383----------------------461-------------470
Sep.----394----------------------481-------------476
Oct.----369----------------------378
Nov.----283----------------------400
Dec.----331----------------------297

 

[Redneck in training]

My system just hit over 30 MWh since beginning and 29.1 MWh for the year. It is just about on track to hit predicted power generation for the year.
Here is a link to an article from The Economist about impact of renewables on the utilities and mainly on energy price.
European utilities: How to lose half a trillion euros | The Economist

 

[dave1949]

The October, 2013 results.
I took the reading this morning since it is going to be low output day that won't add much to the total.

Well above last October and the model. That goes along with the dry month we've had, very few cloudy, rainy spells.

Month--NREL Model (AC kWh)-----2012 Actual-----2013 Actual

Jan.----388----------------------NA--------------440
Feb.----412----------------------NA--------------375
Mar.----509----------------------NA--------------462
Apr.----374----------------------NA--------------487
May----353----------------------NA--------------375
Jun.----308----------------------NA--------------379
Jul.-----341----------------------NA--------------377
Aug.----383----------------------461-------------470
Sep.----394----------------------481-------------476
Oct.----369----------------------378-------------453
Nov.----283----------------------400
Dec.----331----------------------297

 

[dave1949]

Some news on the net-metering front:
NewsDaily: In Arizona, a closely watched vote to decide solar policy's fate

With no pricing or policy details, it's hard to know much from this article. The regulations vary so widely from state to state.

In Maine, we pay a fixed monthly service connection charge of $9.36, like all residential customers, to the distribution utility (the company that maintains the physical grid) regardless of whether we consume more or less than our system produces. We never get paid for any extra production either. We do get a credit against future usage within the following twelve months only.

 

[dave1949]

This is the follow-up to the Arizona net-metering policy in post #455.

Arizona Approves Grid-Connection Fees for Solar Rooftops - Bloomberg

They approved a $0.70 surcharge per installed solar KW. I'm sure that will become a goal to duplicate among utilities everywhere. Oh look, free money. :thumbdown:

 

[Redneck in training]

I would take 0.70/kW/moth. I would pay even more money fixed charge (We pay $32/month) if I could get net metering or at least credit for my own consumption.

 

[dave1949]

The November, 2013 results.

Close to last November and above the model. Lots of sunny days in November. I think December is going to make up for it. Not much clear weather in sight according to the forecast.

Month--NREL Model (AC kWh)-----2012 Actual-----2013 Actual

Jan.----388----------------------NA--------------440
Feb.----412----------------------NA--------------375
Mar.----509----------------------NA--------------462
Apr.----374----------------------NA--------------487
May----353----------------------NA--------------375
Jun.----308----------------------NA--------------379
Jul.-----341----------------------NA--------------377
Aug.----383----------------------461-------------470
Sep.----394----------------------481-------------476
Oct.----369----------------------378-------------453
Nov.----283----------------------400-------------414
Dec.----331----------------------297

 

[dave1949]

The polluters never give up:
ALEC calls for penalties on 'freerider' homeowners in assault on clean energy | World news | theguardian.com

ALEC (American Legislative Exchange Council), the folks the Tea Party is really working for, is pushing for fees and surcharges for home solar systems.

If successful, I really think this could backfire with some unintended results for the polluters. If people have to pay to give away power, they are going to look for ways to use it. Electric vehicles are ready and waiting as a viable solution for many, and they won't be stopping at the polluters gas pumps or buying the polluters electricity.

 

[farmer2009]

Dave,

Just found this thread and haven't had a chance to read it all the way through. But I was wondering how much this had acuaully reduced your utility bills. How much of your usage did you intend on replacing. Seems like you are running as expected maybe a little better.