As I’ve mentioned earlier, though we had planned to run most of our household appliances on solar power, it hasn’t happened yet. Solar power is not economically sensible. By the time you recover your costs and achieve break-even when compared to commercial rates, a good fifteen years may have passed and who knows what kind of maintenance might be required by then. There is a government subsidy for those installing solar power at home, but, as with all things governmental, it is a cumbersome, paper-heavy process designed to defeat the best intentions. So far, it’s succeeding.
Solar water heaters, on the other hand, are easy. They quickly turn out to be cheaper than using electricity to heat water and they have been around for quite a while. They are also now mandated by law for new buildings. Consequently, our solar water heating system – solar system for short – has been in place since a few days after we moved in.
The good thing about the solar system is, you get hot water around the clock and it doesn’t matter if you are in the middle of a power cut or not. This is a huge relief. On several occasions I have been stuck in the morning, unwilling to shower in cold water and unable to get hot water until electricity comes back. Now that doesn’t happen.
You’d think that getting hot water early in the morning would be a problem, considering the sun went down a good twelve hours earlier, but in our case, that’s not a problem. Even when there was a cyclone visiting town – or at least, the side effects of a cyclone, since Bangalore is not exactly coastal and doesn’t get hit by cyclones directly – and we had a gray drizzle for one week without a break, we still got hot water out of the solar system. Apparently, some kind of subdued daylight is good enough.
So obviously, if some kind of subdued daylight is good enough, ten hours of direct blazing sunlight is much too much. And that, my friends, is the problem with the solar system. Too much sun.
I know – you’re thinking, how much of a problem can that be? If the water’s too hot, just run some cold water and mix it, right? Well, yes, that’s what we do. But the thing is, this water is really scalding hot, even first thing in the morning. You could get burnt if you aren’t careful. Ok, we’ve had enough time to figure that out by now and we are careful. But in this aspect, the old-fashioned storage water heater was easier, more predictable. Run it for five minutes and you know you are going to get lukewarm water just the way you like it. Every time.
Still, that’s not the biggest problem. The biggest problem is the volcano effect, also known as the hot water geyser.
In our house, we have several skylights in the ceiling. These are covered with glass. Soon after we moved in, we noticed that sometime in the middle of the afternoon there would be this extraordinary drumming sound coming from the skylights on the first floor. We rushed up to find water bouncing off the skylights.
Water? On the skylights?
That was when we figured out what was going on. The water in the solar system was becoming so exceedingly hot that it was being spewed out the top like steam from a pressure cooker. If we had only put some chicken in there, we could have saved on cooking gas!
Remember what a fanatic Amit is when it comes to water conservation? The thought of all that water turning into steam and escaping into the atmosphere, and of precious water cascading down our skylights and lying on the roof to be lost to evaporation was completely unpalatable. First he called the solar system guys, who said this was completely normal and nothing to lose sleep over. Yeah, right. They had, of course, previously assured him that the water would not get hotter than 70 degrees Celsius, which now only exposed their ignorance. We pointed out that from a lay person’s perspective, it appeared the water was boiling, and they didn’t have an answer to that.
The next thing we tried was to cover a part of the solar panels that trap the heat. We only had some old curtains to cover them with, and I’m pretty certain the curtains have since been blown away.
Next, we called an aluminum fabricator and asked him if he could erect a structure that could be swung across the panels to cover them when it was very hot, and easily removed to expose them when it was not so hot. Sure, he said. 20 k.
The best thing would be to reduce the capacity of the entire solar system by permanently removing some of the panels. But there’s a catch. This is not the panel-type of solar panel, it’s the pipe-type of solar panel. So the elements that trap the sun’s heat (photovoltaic cells, do they call them) are in the shape of pipes that cold water goes through, absorbing the heat as it goes. Removing some of the pipes would involve re-plumbing the solar system, not just removing some plates. Also, once you’ve removed the pipes, what do you do with them? If you leave them lying around in the sun, with no water flowing through them, presumably they’d keep heating up and perhaps overheat or somehow destroy themselves. And then, if you needed to put them back on again, say if your hot water usage goes up when you have visitors or something, then it would be a big hassle.
So for now we haven’t done anything. But in the middle of the afternoon if the volcano begins to erupt then whoever is home rushes into the bathroom to turn on the hot water tap. At first, cold water comes, then nothing. Then there’s the gushing sound of air running through the pipe, then spurts of boiling water begin to follow. Of course we can’t let all that water go down the drain. We collect it in buckets. Doing this forces a fresh supply of cold water through the system and brings the eruption to a gradual halt. In the process, we end up with huge volumes of hot water, which is usually allowed to cool down and then used for mopping the floor or watering the plants the next day. But it’s a headache. There are days when no one is at home, days when the water collected this way is just too much, too heavy to lug around. This clearly can’t be a long term solution.
But neither can this.