PV Gap

Frank Said:

Do Liberals think solar panels on ones house will run an air conditioner on a hot summer day?

We Answered:

"Will run?" The technology improves continually. Not only can solar power currently reduce our reliance on fossil fuels but with improving technology the practical possibility for the exact situation you describe for homeowners is not far off. The problem with cons is that they can't think beyond their noses and they have no vision for the future.

We can't let that kind of retrograde thinking determine how we approach our current and future energy needs.

Wanda Said:

Has anyone got/ using solar panels on their house. Are they effective?

We Answered:

I have solar panels on my roof for heating hot water.

When we were looking into it, we decided not to go for a PV (electricity) system, because they were much more expensive £10K+ and since they only last around 10 years, we’d never have saved anywhere near what we paid for them.

The hot water system only cost around £3K, so we’ll get much closer to saving money long term than the PV system. (Though probably never quite break even).

As to how effective they are; well, let me explain how it works first…

Our hot water tank is large – 210 litre – which, so I’m told, is about twice the size of a normal hot water tank.

The hot water is on a pressurised system, so it works on mains pressure (good for the shower!). This means that the water exits the tank through a pipe coming out of the very top of the tank and cold water enters at the bottom.

The tank is also a twin coil. One coil is about halfway down and heats only the top half of the tank – this coils is hooked up to the gas boiler. The other coil is at the bottom of the tank and heats the whole tank - this coil is hooked up to the solar panels.

Finally, there are two separate thermostats; one near the top, hooked up to the gas boiler, the other near the bottom hooked up to the solar system.

So, when the gas is heating the water, it only heats the top half and turns off when the thermostat reads 65°C.

OK, when the sun shines on the solar panels, it heats the glycol in the lower coil and this heats the water at the bottom of the tank. Warmer water rises above cooler water, of course, so this warm water rises up the tank. The more that this happens, the warmer the water in the top half of the tank gets, and so the less work the gas boiler has to do (when/if it turns on) to get the water to 65°C.

So, how effective is it? Well, here in London, in the winter it’s pretty rubbish. We’re lucky if we get 10°C of warming, even if it’s sunny all day. This is because, the days are short, and the sun is low down.

During the recent sunny March weather though, we’ve been getting 51°C (and remember, that’s the reading of the thermostat at the bottom of the tank – at the top it’ll be warmer.) So, the gas boiler only has to heat (at most) the last 14°C to get to the required 65°C.

During the summer though, it’s great. It regularly hits the 85°C cut off, and remember that’s 210L of 85°C hot water in a well insulated tank, so it lasts days.

In practice, we ended up turning off the automatic daily water heating with the gas boiler, and we only turn on the hot water for 10 minutes or so when we need to. In the winter that’s quite regularly, but in the summer that’s almost never. For example, during March, that 51°C is warm enough, so we tend to leave the gas heater off. We’ve also got into the habit of having our showers in the afternoon or evening, rather than the morning – so that we can take advantage of any hot water we might get from the sun during the day.

One point to make is that 85°C water is *HOT*! (You could probably make tea with it!) We have it set that high because you get the most out of it that way, *but*, until 2 days ago, we didn’t have any kids. You might not want to set it that high if you did have young children in the house who might scold themselves – and if you set it lower, it won’t be as good in summer months because you’ll be wasting heating potential.

Was it worth the £3000? I think so. Like most men I love a good gadget. I still get excited watching the temperatures on the display heat up on sunny days! Then again, that might just be because I’m very sad. LOL

Terrence Said:

Does anyone have solar panels on their house?

We Answered:

I have solar electric panels in my back yard and I think they do great. They are setup with batteries as a battery backup system. On sunny days I normally turn off the utility power and just run the house from solar. It is very nice when the power goes off from the local utility to still have power.

The people all around me has noticed that when they have no lights that we do but none of them has any plans to install. It is the upfront cost that stops most people.

Danny Said:

Why did president Bush, jr. take Jimmy Carter's solar panels off the top of the white house?

We Answered:

Solar White House
In 1977, Jimmy Carter had solar panel installed on the roof of the West Wing, on top of the Cabinet Room. These were removed in the Reagan era because of leakage problems, but around 2002 were reinstalled by the second Bush administration, along with new solar collector systems on the Swimming Pool cabana and groundskeeping building.