Newbie Electric Radiant Floor Heating tied with Solar

Hello to all.
I am new to the forum along with being new to the renewable energy movement.
I currently work for a solar distribution company installing solar arrays for schools. I am on the design side of aspects, but more or less just starting out.
My wife and I just sold our house and are looking to build once again. With being able to get panels and such at a discount through my work, I want to take advantage and use as much solar as I can for this new house.
My ideas are as follows:
2000 square foot house, 2x6 wall construction both interior and exterior walls.
Spray foam insulation
Crawlspace sealed and dried (Not heated)
Electric Radiant floor heating throughout the whole house (main heating source)
AC Furnace installed for back up heating through propane if need be.
Instant water heater (Found a unit to manipulate the water heater tanks to run directly off of solar http://techluck.com/index.php#buy
)
5 bed 2 1/2 bath 2 story rectangle design (Can send floor plans if need be)
We have 1 child with plans of having 3 total and would like to stay in this house extensively.
I do some mig welding on a small Forney 110V welder and do other projects in the garage as well.
I am wanting to size this correctly for a grid tied system using Microinverters to control the setup. I'm more of a fan of having them all run separately and the installation will be a diy up until it has to be connected to the grid.
I'm in the north east corner of Indiana.
Just needing some help sizing it correctly and making sure we're not buying way more than we need to so any help is greatly appreciated.
I am new to the forum along with being new to the renewable energy movement.
I currently work for a solar distribution company installing solar arrays for schools. I am on the design side of aspects, but more or less just starting out.
My wife and I just sold our house and are looking to build once again. With being able to get panels and such at a discount through my work, I want to take advantage and use as much solar as I can for this new house.
My ideas are as follows:
2000 square foot house, 2x6 wall construction both interior and exterior walls.
Spray foam insulation
Crawlspace sealed and dried (Not heated)
Electric Radiant floor heating throughout the whole house (main heating source)
AC Furnace installed for back up heating through propane if need be.
Instant water heater (Found a unit to manipulate the water heater tanks to run directly off of solar http://techluck.com/index.php#buy
)
5 bed 2 1/2 bath 2 story rectangle design (Can send floor plans if need be)
We have 1 child with plans of having 3 total and would like to stay in this house extensively.
I do some mig welding on a small Forney 110V welder and do other projects in the garage as well.
I am wanting to size this correctly for a grid tied system using Microinverters to control the setup. I'm more of a fan of having them all run separately and the installation will be a diy up until it has to be connected to the grid.
I'm in the north east corner of Indiana.
Just needing some help sizing it correctly and making sure we're not buying way more than we need to so any help is greatly appreciated.
Comments
I should mention this, and excuse me if you already know this, but the microinverters will only work when they are connected to the grid. You can configure them to sync to the grid in order to operate and with an Envoy they can be configured for Non Export. I do not understand what you mean when you say you want the micro inverters to control the setup?
For heating, looking at a heat pump system (air source is generally more cost effective vs ground source)... Depending on your weather and requirements, a heat pump in a >~50F ambient is 2-3x more efficient vs resistance heating. As you get below freezing, then other heat source(s) are generally needed (I am not a heating engineer--Lots of interesting research ahead).
There are other ways of saving money too... For modern homes that are tightly sealed--Then you probably want an air exchange system to conserve energy:
https://www.ecohome.net/guides/2362/ventilation-air-exchangers/
Using Mini-Split Heat Pump systems have been pretty popular for heating and cooling. And you don't have to run ducts throughout the home (and the additional air leaks and insulation that come with ducting).
Are you going to be tied the "grid" (utility power)? Or are you looking to be "off the grid" (solar panels+solar charger+battery bank+AC inverter+backup genset, etc.)?
In general, if you are looking for off grid power--Keeping your power usage in the 3.3 to 10 kWH per day (~100-300 kWH per month) is where you want to aim for. A typical North American home uses in the range of 500-1,000 kWH per month.
The other issue is how much sun do you have... For example, Fort Wayne Il, fixed array, facing south:
http://www.solarelectricityhandbook.com/solar-irradiance.html
Fort Wayne
Measured in kWh/m2/day onto a solar panel set at a 49° angle:Average Solar Insolation figures
(For best year-round performance)
Just to give you a very rough idea of what a 500 kWH per month electrical usage for a Grid Tied system could look like:
- 500 kWH per month * 1/30 days per month = 16.7 kWH per day = 16,700 WH per day
- Say a minimum of 4 hours per day of sun
- 16,700 WH per day * 1/0.77 GT solar system eff * 1/4.0 hours of sun per day (average) = 4,175 Watt array
- If you use 300 Watt solar panels:
- 4,175 Watt array * 1/300 Watts per panel = 14 panels
If you are looking for Grid Tied Solar, you will have to find out from your utility what the billing plan is for GT solar... It is not always "obvious" what the final numbers will look like (Time of Use billing, monthly or yearly true-up of energy usage, monthly minimum charges, etc.).And 500 kWH per month is a pure guess... Look at your old power bills and see how much you really use. And 500 kWH per month--With radiant heat/hot water/cooking (vs propane)--You might have to work real hard to keep your electrical usage that low for a 5 bedroom home.
Working with architects and contractors that are familiar with solar/alternative energy home design (as needed) should be able to give you much more accurate numbers for your design and energy needs.
-Bill
How long have you been installing microinverters ? Had any batches of bad ones ?
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Skim coat with a styrofoam sub floor, not the best because the thermal mass is reduced, a proper slab would retain heat for a longer period, a heat pump with slab heating would be ideal, not a retrofit opinion however.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
I am going to use the radiant electric floor heat in given areas (Bathrooms, kitchen, etc.) for supplemental heat and comfortability and I do like the idea of mini split systems for their efficiency, but don't like how there would need to be so many for our setup.
I will look into heat pumps with the propane furnace as a backup. We may also change the design the foundation to a slab with insulation on the foundation walls as I need to research more ideas in that area.
I am still in debate with going with an instant water heater or electric water tanks for the setup. For the instant water heater, my plumber mentioned they run more efficiently through propane heating source rather than electric but don't want many appliances on propane. On the other hand, there are units out there like this http://techluck.com/index.php#buy that hook directly to the heating elements for the water tanks and would like to designate some panels for that purpose as well.
As far as micro inverters, I was under the impression they control at 1 panel level meaning if there is shade on a small portion of the array, it doesn't bog down the remaining unshaded panels and makes those perform at their peak. That was my impression of microinverters. What are the pros and cons of a central inverter and microinverters?
I will be grid tied until the battery industry is a bit better and longer lasting chemistries. With the advancement in electric vehicles, I feel there will be a big swing in the battery technology and would like to wait a bit until such batteries are researched and tested. Until then, I would have no problem switching to off grid and doing the overhaul of the array at that point.
Grid tie you can really do whatever you want. You can have shaded panels that we would never do offgrid. Same with solar. We would build a ground mount for solar as the only thing we want on a roof is rain or snow.
Just some contrast for you. Good Luck!
http://members.sti.net/offgridsolar/
E-mail [email protected]
So our electric demands are as follows:
- Electric radiant floor heating by Warmly Yours. Uses 15W/sqft having around 2500 sqft of livable heating floor space. Thats in a 240V wires.
- Tankless hot water heaters. 3.5 bathrooms ( 1 master bath, 2 full baths and 1 half bath) Wanting to possibly use point use instead of a whole house tankless setup (match the demands per area with the gpm of the unit we choose) Our incoming water temp for our zone in north east indiana is around 47 degrees.
- Solar amperage for 72 panel of 325W modules using the new Enphase Iq8 micro's when they come out. They're 9 panels per breaker having around 11 amps per string and having 8 strings resulting about 88 amps for the solar setup.
-The normal house electrical demand as per usual.
So my question and advice seeking is, how much amp service can I get and would the solar be able to handle these items with how many panels I am wanting? I've done a heat loss calculations and will be applying a more Passive house sealed construction with Zip R sheathing setup and other air and water tightening techniques for this house.
Of course, there are "details" to any answer... Very cold weather (freezing and below), heat pumps become less efficient. So lots engineering/planning work would be needed.
I am assuming you are looking at a Grid Tied inverter system (more efficient, least cost, little maintenance vs battery based hybrid inverter systems).
The issue with tankless electric water heaters--The draw a very large amount of current--And the cycling on/off the heaters can cause noticeable (and sometimes objectionable) "blinking" of the lights. With modern LED fixtures--It is possible that they will be less susceptible to variable output vs the old filament based lamps (and florescent, etc.).
Why are you looking at tankless electric water heaters vs just normal tanked heaters. The efficiency is about the same (both are ~100% efficient heating)--Of course you have some losses due to heat loss through insulation and hot water in pipes (and in a circulation system if you want instant hot water at the tap).
You also need to work with your electrical utility... An >10,000 Watt GT solar system may trip further reviews, possible transformer/distribution system upgrades by the utility... Even your home, if you have an >200 Amp main panel may trigger an engineering upgrade too... If you add an electric vehicle charging station--Another energy sink.
In general, a typical home in your area may be 1,000 kWH per month... And down in Texas with full A/C in summer--Perhaps >3,000 kWH per month.
And will you have a genset for emergency/backup power? Will it power a subset of your home--Or do you want it all (water heaters, floor heating, non-propane appliances, etc.).
The genset itself will not be cheap (if a large unit)--You may have issues with backup genset on site--And fuel issues (propane, diesel, etc.).
Is there anyone in your area that has designed/built a home in the class you are looking at?
Also--There is a big "green push" in parts of the USA. And that can range from prohibiting Natural Gas in new homes/businesses (shakes head). And eye watering electric bills for "green power". While you may have reasonably priced power now--Looking at conservation & energy efficiency now can save you a bunch of money in the future.
Baseline is only ~300 kWH per month... So you are looking at $0.20 to $0.40 per kWH (winter/summer/off peak thru peak.
For folks that are paying $0.10 to $0.20 per kWH--There are going to be some big shocks if renewable energy is legislated in their regions.
GT power is pretty cheap to generate (~$0.10 per kWH is certainly not difficult). But utilities are starting to change their billing plans to change the economics of GT solar power... Higher per month fixed costs. Only "paying" for generation costs (about 1/2 the total $/kWH charges) or even "outlawing" new GT Solar connections. In a few areas, people got permits to install GT solar, but the utility refused to allow connections to the GT solar farm "because"...
In our region, our utility will "grandfather" existing systems for 10 years (rate plan choice)... After that, the reserve the right to change the agreement (through the state PUC).
I highly recommend that you look at conservation/insulation/etc. first. lt could save you much money down the road.
-Bill
My present electrical rates (northern California):
https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHEDS_E-6.pdf
(T) TOTAL RATES Total Energy Rates $ per kWh)
PEAK PART-PEAK OFF-PEAK
Summer Baseline Usage $0.40545 (I) $0.28701 (I) $0.21179 (I)
Over 100% of Baseline $0.49198 (I) $0.37354 (I) $0.29832 (I)
Winter Baseline Usage – $0.23296 (I) $0.21613 (I)
Over 100% of Baseline – $0.31949 (I) $0.30266 (I)
TIME PERIODS: Times of the year and times of the day are defined as follows:
Summer (service from May 1 through October 31):
Peak: 1:00 p.m. to 7:00 p.m. Monday through Friday
Partial-Peak: 10:00 a.m. to 1:00 p.m. AND 7:00 p.m. to 9:00 p.m. Monday through Friday Plus 5:00 p.m. to 8:00 p.m. Saturday and Sunday
Off-Peak: All other times including Holidays. Winter (service from November 1 through April 30): Partial-Peak: 5:00 p.m. to 8:00 p.m. Monday through Friday Off-Peak:
All other times including Holidays. Holidays: “Holidays” for the purposes of this rate schedule are New Year’s Day, President’s Day, Memorial Day, Independence Day, Labor Day, Veterans Day, Thanksgiving Day, and Christmas Day. The dates will be those on which the holidays are legally observed.
Of course, they already promised not to blow up another neighborhood and kill 8 people with a natural gas pipeline explosion due to faulty maintenance/records since 2010...
https://www.sfgate.com/news/article/PG-E-s-household-customers-facing-8-increase-in-15774384.php
https://en.wikipedia.org/wiki/San_Bruno_pipeline_explosion
-Bill
Heat pumps have higher COP's than straight electric even at sub 0 temps. In my opinion anything straight resistance is a poor use of solar power when heatpumps have COP's of over 3 and resistance has a COP of 1. I don't recommend Geothermal because of the initial cost and COP's start dropping in the cold month's of winter as the heat is removed from the ground or water table.
Sanden also makes an air to water heatpump for domestic HW, you could also possibly use multiple Sanden units for radiant space conditioning.
So the OP is in California? Unless he is coastal the offgrid method will be far cheaper and probably less pollution. Solar domestic hot water in a 50 to 75 gallon tank backed up by gas. 6 good collectors with drainback if he freezes. A few grundfos pumps. All of it can run off less than a couple hundred watts. Even less power if he get creative with direct venting.
It is getting harder to find good plumbers who know solar domestic and so heat pumps do make sense except for offgrid. If you did it offgrid, it would be fine as long as you had a complete back-up for winter/storms when you need to save the electrons.
http://members.sti.net/offgridsolar/
E-mail [email protected]
http://members.sti.net/offgridsolar/
E-mail [email protected]
It sounds like he has an aversion to use of propane... I have met a few people that prefer electricity over natural gas or propane... For propane, other than the costs/tank(s) type issues--There is (as I understand) the real issue of propane being heavier than air and having propane settle into low spots is a real issue (natural gas is mostly methane which is lighter than air and will tend to dissipate better).
And in much of the USA, vent-less (unvented) propane/natural gas heaters are allowed... But I would certainly avoid them in my home (in California, one of the few states where V-L heaters are outlawed--sort of).
https://www.ventless-gas-fireplaces.com/ventless_products_code_information.html
I don't trust our state PUC (public utilities commission) at all... Seems to be all political and about the money (surprise). For water, our water costs have gone up by 7 times or so in SF Bay area--Much of it do to earthquake proofing/rebuilding our water infrastructure (100 years old and hardly any maintenance during that time?). Much of SF water comes from the mountains near Yosemite.
https://gizmodo.com/how-san-franciscos-clean-drinking-water-destroyed-the-1605614294
Anyway... I suggest conservation as a start for any new/major home upgrade now. The cost and difficulties of energy (and water?) appear to only be getting worse in the future. For a person that has never done any conservation projects in their home--I suggest it is not that difficult to reduce energy usage by 1/2... However, the expenses for new appliances/furnace/heat pumps/insulation, etc. are not cheap--But they tend to be one time costs--Vs the monthly power costs (and/or the cost of off grid solar systems and their maintenance costs for "larger" systems).
Grid Tied Solar still leaves you connected to the grid and the politics of the grid. At any time, the powers that be can change the agreement.
Folks like Dave living off grid (battery based solar) don't have the politics of utilities issues (at least not yet)--But are still impacted by state policies (wildfires from power distribution failures, poor forest/lands management, etc.)...
-Bill
When we get impacted by any of the crazy stuff west of us, it is either Nevada or Texas. I am on our Fire council here in the county trying to get them to harden the town. If they lose the town, like Paradise we will leave. Gruesom has mandated our 8 bed hospital to be earthquake safe and the tax gets voted down by the ranchers and farmers in our Red county. So that may force a move east.
Maybe we will be neighbors Bill? With all of the C19 in Clarke county (out of Vegas) we are looking again at Carson area but really want out of the snow. I keep my reference on a place where I put my parents when they got too old and demented. It was called the Remington near San Diego. It had it all from a house, everything in between, to memory care. A Vons across the street. Great Rock shows at a casino. Did not need to drive.
Edit: Except it was in California....
http://members.sti.net/offgridsolar/
E-mail [email protected]
http://members.sti.net/offgridsolar/
E-mail [email protected]
Vented (direct, power vented, condensing, etc.) have combustion products going out a flue/directly outside. There are some sealed units that also take outside air too (avoid taking conditioned air into the "heater")--Direct Vent(?)...
In California (and Texas/Utah/other states?), we now have NOx smog control regulations even on gas water heaters (and HVAC in general coming/now?).
-Bill
http://members.sti.net/offgridsolar/
E-mail [email protected]
They meet Cal requirements back to 2002 when I did my first hydronic here. Just bought one for a client last month.
For Offgrid, building a house, or retrofitting. With a tank 40 feet or so up the hill, one can take a hot shower without any electricity.
You can see the 2 flues in the pix.
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Bill: to further answer or comment on your remarks, I am against propane for both the environment and the monthly or one time reoccurring bill that we are trying to eliminate.
As far as insulation: the new construction house is going under details of air tightness and other potential leaks. We are planning on using the ZIP R sheathing and the ZIP System for our home along with an insulated foundation (slab on grade) and 2x6 or 2x8 walls, spray foam, and other sealed techniques. I've been watching a lot of Matt Risinger on YouTube for his builds and how he constructions them for more efficiency. I'm still stuck on the heating elements in the house due to my aversion to propane. The heat pump does well under the right conditions but with a house of 5, I don't necessarily want to take any chances. Could I do a possible hybrid using electric radiant floor heat in the bedrooms and bathrooms and let the heat pump take care of the rest of the house? It's a 2500 sqft 2 story house. So again, the heating element is still a big question mark.
As far as the water heater, I don't like the fact of standby heat loss with electric water tanks. Plus we have a 50 gallon hot water with only 1 child at the moment, and we run out of that daily scurrying in the shower to get the last bit of hot water. So for that, maybe double or triple up the 50 gallon tanks and throw an insulated heat blanket on them? If so, then I would have to find some room in the floor plan to stuff those. Another aspect on the tankless is I can have hot water for as long as I like, theoretically. So not sure on there. My cousin who is an electrician has gone through the amp draws of the units I am looking at and suggest a 400 amp service for the house to accommodate for this.
I do appreciate all of the feed back greatly. We have a lot of time to plan and build and would want this house to be efficient as possible without sacrificing the daily habits. We don't use a lot of energy either. I think in our old house, we used maybe 700kwh a month on average so way below the average we have now.
We are looking into an off grid set up, but want to wait a little until the battery technology advances but would like to set up a grid tied system to have the advantage to switch over at a later date.
That said, very hard to go back to the grid life. Love this way too much! Good Luck!
http://members.sti.net/offgridsolar/
E-mail [email protected]