china/India - Cop 26

Ok, I see how the figures Sam B1 is quoting could stack up on efficiency but running cost is another perspective that is probably more important to the average householder than efficiency. On the efficiency question the figure Sam quoted for generation efficiency is a little lower than my off the cuff guess but the transmission loss a little higher so ball park around what I was expecting.

In terms of cost the latest averages I can find for September despite the gas price rises put electricity per kWh at around 4.3 times the cost of gas. I also did a bit of digging on heat pump COP and it would seem that yes a COP of 4 or higher is achievable in ideal conditions but the norm is between 2.5 and 3.5 - so considering the high capital cost plus the higher running cost only the most dedicated of greens would be attracted.

In Dave's (SOD) example of heating use a heat pump system considering its apparent average limit of 40 degrees C on the hot side he would need to be running it considerably longer to get the same heating rise in the house?

Seems another example of the gap between environmental sustainability and economic sustainability to me. Granted price differentials may change between energy sources and legislation may drive change but if it's the latter there will be a lot of people driven below the poverty line.

Paul.

As I understand it, heat pumps will basically need to be run 24/7 throughout the colder periods in order to keep the mass of the building warm - coming home to a cold house and then turning the heating on to warm the place up for the evening will no longer be an option. It may just about work in well-insulated structures with low thermal inertia, but not in traditional UK builds. Additional heating will be a necessity, along with long woolen underwear. Winter draws on, as they used to say

Rob

I'm now looking at replacing a gas wall heater which seems to have developed a fault in its control board, now obsolete. If it wasn't gas I'd have a go at making one from an Arduino. 2 fans, various sensors and a board full of electronics. My first gas fire had an on/off valve and you lit it with a match. OK I'd have a flame failure device nowadays, but the replacement will be as simple as I can get. Heat pump sounds to me to have the potential for a lot of expensive maintenance.