In my previous Photovoltaics for Domestic Hot Water post I said I'd write more on the use, caveats and interpretation of that calculator later. A recent thread on the Navitron forum triggers me to write about some of this.
More...I've previously written about the possibility of using the output of photovoltaic panels for heating applications in circumstances where traditionally solar thermal (evacuated tube or flat plate) panels would be used: PV For Space Heating, PV, ETs and Flatties and, slightly less interestingly, Solar By Area.
Since then the price of PV has continued to drop. At the moment Navitron, for example, are doing Kinve 235 W panels at a fraction over £0.57/W (incl. VAT) compared with another supplier's £0.74/W + VAT at the beginning of the year. In the mean time I've been fiddling around doing a calculator web page to try to explore the trade offs in systems which combine solar thermal with a heat pump driven by photovoltaic panels. I'm not happy with the design of this yet (it works as intended but it's difficult to get anything very insightful out of it) but playing with it a bit did show over how wide a range of operating conditions the costs of output power of PV and solar thermal are similar.
This page is, therefore, a simplified version of that calculator designed specifically for comparing the cost of power from PV and solar thermal.
More...For anybody who hasn't corresponded with me recently it must be a bit of a puzzle what's going on with my house build project. Or, to put it a bit more succinctly, WTF have I been up to? I'll start from the beginning...
More...Some comments made on other people's blogs:
More...My House Sketch shows evacuated-tube solar-thermal panels along the bottom of the south roof. An offer came up which would save at least £1200 relative to possible alternatives so, with a bit of prodding by skyewright, I ordered them the other week and they arrived on Tuesday. I had to have a play, of course.
More...As mentioned in a previous post I have a few small PV panels out in the garden feeding an old battery via a Morningstar TriStar MPPT 60 charge controller. With the experience of playing with this controller I'm having some second thoughts about how worthwhile MPPT still is as PV panels get cheaper.
Hearing of two of these failing in a short time also helps to undermine my resolve. [Update 2013-07-24: …and another one bites the dust.]
More...My previous entry, PV, ETs and Flatties, compared the outputs of various solar panel types by price. If, like me, you're designing a house to have a large south-facing area for solar collection then this makes sense as price is the key factor. However, if you have an existing house which is not designed with solar collection in mind then area might be the limiting factor. Following a request by Wookey here's a similar graph normalized by area.
More...The overview of my house plans (at House) are a bit out of date. The design has, as you might expect, evolved a bit (and is still evolving) and it never seems like quite the right moment to bring it up to date. That's one of the points of this blog: a blog post is only supposed to be right on the day it was posted; etiquette says it's “cheating” to later update an entry in more than the most trivial editorial ways without clearly marking what you've done.
Anyway, here's a quick sketch of more current thinking.
More...Following on from my previous PV For Space Heating post, it's interesting to consider what combinations of photovoltaic (PV, electric), evacuated-tube (ET) and flat-plate (thermal) solar panels make sense, particularly for the provision of space heating and domestic hot water (DHW) for any significant proportion of a winter not close to the tropics. First, a look at the performance of these panel types.
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