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David Hrivnak

SalesEngineering,
EcoLogical part time

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SalesEngineering,
EcoLogical part time

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1 to 20 of 50+ total

RE: Solar Noon Tuesday - Understanding Solar Carports

Posted By David Hrivnak 11-12-2025 10:57 AM
Found In Egroup: Everything Solar Forum \ view thread
Just a thought you might want to consider posting about your UPCOMING discussion rather than after the fact. It is hard to join into a Zoom discussion after it has ended. ------------------------------ David Hrivnak SalesEngineering EcoLogical part time ------------------------------

RE: Should ASES be educating more about efficiency-first building strategies?

Posted By David Hrivnak 08-30-2025 06:38 PM
Found In Egroup: Everything Solar Forum \ view thread
Yes absolutely. As an owner and builder of a passive solar and well insulated home it definitely makes a difference. With our 9.5kW solar system we have enough to power our home AND vehicles. Energy efficient appliances like inverter driven heat pump and a heat pump water heater help along with all ...

RE: Wireless Photovoltaic (PV) Technology

Posted By David Hrivnak 08-04-2025 04:32 PM
Found In Egroup: Everything Solar Forum \ view thread
While a cool concept, and I am sure they will grow it. 1kW over .6 miles, is not worth much in my book. Two solar panels and a Bluetti would likely produce more for a far lower cost. ------------------------------ David Hrivnak SalesEngineering EcoLogical part time ------------------------------

RE: Wireless Photovoltaic (PV) Technology

Posted By David Hrivnak 08-04-2025 11:04 AM
Found In Egroup: Everything Solar Forum \ view thread
To me microwave ovens are safer as they are shielded, very little of the radiation escapes from what is essentially a Faraday cage. ------------------------------ David Hrivnak SalesEngineering EcoLogical part time ------------------------------

RE: Wireless Photovoltaic (PV) Technology

Posted By David Hrivnak 08-01-2025 10:12 AM
Found In Egroup: Everything Solar Forum \ view thread
The slight problem here is with AC current, even wires will generate EMF. So while likely a lower level, you will still get a dose from the wiring in the house. ------------------------------ David Hrivnak SalesEngineering EcoLogical part time ------------------------------

RE: comparing Enphase microinverter with Solar Edge string inverter with battery

Posted By David Hrivnak 07-07-2025 11:45 AM
Found In Egroup: Everything Solar Forum \ view thread
I have installed both SolarEdge and EnPhase. For us the wiring is slightly easier with SolarEdge on the roof with their optimizers. I also like their DC coupled battery as it is about 10% more efficient as you skip an AC to DC conversion. BUT I like EnPhase support better. Performance wise the two are ...

RE: nest under the solar panel

Posted By David Hrivnak 06-11-2025 10:44 AM
Found In Egroup: Everything Solar Forum \ view thread
I would not say it is common, but it DOES happen. Usually not a problem with birds, but squirrels can occasionally chew on wires which can be a problem. ------------------------------ David Hrivnak SalesEngineering EcoLogical part time ------------------------------

RE: Adding storage after panels are installed

Posted By David Hrivnak 06-09-2025 10:48 AM
Found In Egroup: Everything Solar Forum \ view thread
There are many variables but typically storage can be added, FranklinWH has a nice AC coupled solution, and it can be from another company. But I would need to know more about your install before one can give a definitive answer. For example if you have a SolarEdge system it may be easier to add a SolarEdge ...

RE: Jimmy Carter's environmental legacy set the foundation for today's climate action

Posted By David Hrivnak 01-10-2025 05:22 AM
Found In Egroup: Everything Solar Forum \ view thread
My home may be an anomaly as I designed it as passive solar. So compared to a typical house we get more winter solar gain and a lot less gain in the summer. Three of the last 4 years my PV array has produced more power than the house AND cars have used making us a net exporter of power. https://www. ...

RE: Jimmy Carter's environmental legacy set the foundation for today's climate action

Posted By David Hrivnak 01-08-2025 12:06 PM
Found In Egroup: Everything Solar Forum \ view thread
Thanks Keith, unfortunately the link does not seem to work for me. That said if you compare the energy labels on the Rheem HP water heater today I see a 1/3 cost of usage so call it a COP of 3. I also have thermal, prewater heater that in 25 years, I have had to replace the tanks twice, and the glass ...

RE: Jimmy Carter's environmental legacy set the foundation for today's climate action

Posted By David Hrivnak 01-07-2025 07:28 PM
Found In Egroup: Everything Solar Forum \ view thread
Keith sorry to disagree, but I must. PV is 20-24% efficient these days. with a degradation of .08% a year. So very different than your numbers. And the COP of my HP Water heater is right at 4 as the energy star label is 1/4 that it's electric cousin. And now instead of 1 40 or 50 gallon tank I need to ...

RE: Jimmy Carter's environmental legacy set the foundation for today's climate action

Posted By David Hrivnak 01-07-2025 06:51 AM
Found In Egroup: Everything Solar Forum \ view thread
Very well said William, and this follows my experiences including designing two passive solar homes and some 75 PV solar systems. Thrice now I have been involved with some thermal solar for hot water. ALL three have developed leaks within 6 years or less, and two systems removed. Yet my 11.5 year solar ...

RE: Jimmy Carter's environmental legacy set the foundation for today's climate action

Posted By David Hrivnak 01-02-2025 03:58 PM
Found In Egroup: Everything Solar Forum \ view thread
I fully agree William, Solar PV is far flexible as you can use the power for ANYTHING, heating, cooling, hot water, EV charging.... and new inverter air source heat pumps are a very efficient way to heat and cool a house. ------------------------------ David Hrivnak SalesEngineering EcoLogical part ...

RE: Read our innovation-showcase issue of Solar Today

Posted By David Hrivnak 07-27-2024 04:39 AM
Found In Egroup: Everything Solar Forum \ view thread
William, I think you forgot to include the Heat Pump efficiency of about 400%. Yes 400W of resistance heating would give 1364 BTU/hour. But a Heat Pump gives about 5,500BTU/hour. So run time should only be 4 hours not 17. PS My home is well insulated and passive solar so that could be a reason our ...

RE: Read our innovation-showcase issue of Solar Today

Posted By David Hrivnak 07-26-2024 03:31 PM
Found In Egroup: Everything Solar Forum \ view thread
Sorry but having installed and lived with both I MUCH prefer a heat pump water heater over solar thermal. And they are far less costly to install. I am nearby in NE TN and there is a large part of the year where the roof plates are not hot enough to fully heat the water so you need a lot of supplemental ...

RE: Need advice on solar panels for field station

Posted By David Hrivnak 05-24-2024 01:23 PM
Found In Egroup: Everything Solar Forum \ view thread
That would work. You need the included charge controller and I have had Renogy products that have worked well for me. If they will be moving a lot and can't mount them on the roof maybe a foldable option like this would work better. But if they have room to mount on the roof and/or they are in the same ...

RE: What policy topics do you think Solar Today should cover this fall?

Posted By David Hrivnak 05-04-2024 05:47 PM
Found In Egroup: Everything Solar Forum \ view thread
I would like to know if there are any chances for streamlined permitting in the US or areas of the country that have streamlined permitting we can point local authorities to. ------------------------------ David Hrivnak SalesEngineering EcoLogical part time ------------------------------

RE: Cleaning panels

Posted By David Hrivnak 04-30-2024 10:41 AM
Found In Egroup: Everything Solar Forum \ view thread
Likely not. I live in NE Tennessee not a very different climate. My solar has been on for over 11 years now. There is an array I can easily reach and one that is hard to get to. Once I cleaned the easy to reach array and comparing to the string that was not cleaned my production dropped, slightly but ...

RE: current PV install cost per watt ?

Posted By David Hrivnak 06-23-2023 11:15 AM
Found In Egroup: Everything Solar Forum \ view thread
There are many variables, size of system, ease of working on the roof..... We are a small time installer and typically will see as low as $2.25/watt on a large job with easy access to $3.30/watt for smaller installs on a challenging roof. There is a certain amount of fixed costs that small 4-6kW systems ...

RE: Solar powered factories making hemp batteries and the future is hemp buildings?

Posted By David Hrivnak 04-08-2023 02:35 PM
Found In Egroup: Everything Solar Forum \ view thread
As for a Hemp battery and EV's I think the proponents have been smoking too much hemp. look up the power density of hemp batteries and I see an energy density of about 20 watts/kg. A Tesla Model 3 has about 80kWh pack. So if the battery were made of hemp the weight would be 4000 kg or 9000 lbs, or 9X ...