combination natyral gas/electric boilers

tim smith

From what I have read and talked with the solar guy's about, this seems to be a much more efficient method of using solar, espcially where you have domestic hot water and Hydronics. I am not speaking from experience just from what I have researched. Any input?? Tim

RojoHo_3

combination natural gas/electric boilers

I always appreciate the advice and views of all who contribute to the Wall. Have any of you professionals here installed combination natural gas/electric boilers? I'm considering a photovoltaic system, which would only be cost effective if I can use electric surplus power for a boiler.

jp_2

wow

thats a lot of surplus power.

have you played around with some numbers? how much surplus do you expect to have in the winter?

SPB

surplus power

I know I need some. I, also, have hade simular ideas except with radiant electric floor. Don'r know id I am comfortable with the research yet. where I live electric and propane cost the same. We have almost as many people on natural gas as propane. (Natural gas is bearliy less expensive than propane. I'm in colorado where a large amount is coming from, ( a different gripe for a different day) with tile floors and assuming your are on fuel oil, or propane with an extreamly large photovoltaic system you might break even( with out considering the cost of the system. I like the idea and I am looking into it, myselt. I read and hear there might be some stystms coming that might deliver a beter return.

Gordy

How many acres

Of PV panels are you putting in?

Personally I don't think that PV technology has come far enough yet 37% efficiency on the cusp so they say. Thats a big leap from 10%. How long will they last after the warranty, and how long efficiency lasts are big ifs.


Gordy

SPB

still need surplus power.

As I attempted to say, weare not there yet. I have actually call some photo. suppliers and they agree we don't have the systems. Yet. There are claims in the news some are coming. I think these, at best, would only supplimnt your heat. There are claims by the elec. Radiant people that you can do all your heat this way. I'm not completely sure myself. But it does look promising in certain houses and areas. I would do a good heat loss first. I like the idea of spot heating with elec. better. I have some in my bathroom and love it. With the tax incentives it may work when the panels get better.

jp_2

doable

it certainly is doable and has been done. I think "kevin in denver" has posted a house heated by a PV system.

to me it seems more viable to heat water directly by the sun. the cost of a 1000watt solar collector seems a lot less than a 1000watt PV system that heats water.

keep the PV for the lights and use solar collectors for the water.

any surplus electricity should be stored for night time use, a lot of excess points to improper design, my opinion.

Unknown

Kevin was very interested in a study posted here that showed a very poor utilization efficiency from a fully monitored DHW system.

The big difference between net metered P.V and solar Thermal is storage. With net metering any excess capacity is "returned" to the grid at retail price. Solar thermal is a use it or loose it proposal. Even though thermal collectors can perform at much higher efficiencies than P.V, these efficiencies are of little significance if we must store this thermal energy for any significant length of time.

One thing that net metering advocates ignore is that while the user is reimbursed for energy put back into the grid at retail pricing, It is debatable how effectively this micro generation is actually utilized. Just because you put an electron into the grid does not mean that this electron will actually end up doing useful work. The current electrical grid was not designed for distributed generation, centralized power plants are not necessarily capable of throttling back as solar inputs wax and wane.

The idea of generating P.V electricity converting it to heat and storing it for later use seems highly questionable to me. P.V now has an upper hand because of favorable net metering rates and higher incentives, IMHO making P.V do thermal is a waste, except in some limited situations.

RojoHo_3

Thanks everyone

for the impute. For now I'm going with a gas fired Prestige, but I'm providing a sub-feed for future electric and photovoltaic. By the way I'm in the San Francisco Bay area and we have to carefully look at the cost effectiveness of photovoltaic. I'll post more as the situation evolves. I can see that the future here will favor a duel fuel boiler.

Rich Kontny_3

I Like the Freewatt

Concept by Climate Energy, they are marketing their hot air unit already and will soon have a boiler system also.Ideally I would use this as my primary source supplemented by a conventional system hooked in parallel.

There are so many different ways to tackle this fuel spike and it creates many opportunities.

Rich Kontny_3

I Like the Freewatt

Concept by Climate Energy, they are marketing their hot air unit already and will soon have a boiler system also.Ideally I would use this as my primary source supplemented by a conventional system hooked in parallel.

There are so many different ways to tackle this fuel spike and it creates many opportunities.

Google or search: Climate Energy.com

jp_2

costs per BTU

thats what you need to look at. how many BTU's can you collect for $5,000?

A super insulated structure is your best bet.