Energy Crisis Looming?

[armsid]

As sam triple said about new builds having solar panels the answer is roof tiles could be used as solar panels will not look out of place and could be made by the millions saving quarry tiles being made just think  of it a win for all

[JohnfromUK]

2 hours ago, Yellow Bear said:

Even 15 years ago a 40/45 c temperature was regularly obtained with a slinky at 6/700 mm deep.

I'm not 100% sure, but I think the 'hot' temperature won't have changed significantly as it is a physical property of the fluid used.  You have to compress the fluid in its gaseous state to make it condense (which gives out the heat).  The maximum temperature at which condensation can be made to happen (which determines the maximum fluid temperature is the limit and this is a 'property' of the fluid concerned.

[Yellow Bear]

1 hour ago, JohnfromUK said:

I'm not 100% sure, but I think the 'hot' temperature won't have changed significantly as it is a physical property of the fluid used.  You have to compress the fluid in its gaseous state to make it condense (which gives out the heat).  The maximum temperature at which condensation can be made to happen (which determines the maximum fluid temperature is the limit and this is a 'property' of the fluid concerned.

I had a thought that the new"green" refrigerants may have improved this.

[oowee]

15 hours ago, JohnfromUK said:

Possibly on a mild day, but the vast majority of air sourced ones drop MUCH lower than that at low air temperatures.  Ground source can be much less variable, but you need a big area and deep gathering pipes, which is hugely expensive.  Cannot be done under trees either.

For air sourced Coefficient of Performance (COP) of 2.5 to 2.8 is typical.  I quote from here https://www.greenmatch.co.uk/air-source-heat-pump/performance

"That is the ratio of heat produced per unit of electricity consumed when pumping the heat. Efficiency performance tends to decrease during periods of severe cold.

For comparison, in mild weather COP can be about 4.0, but when the temperature drops to 0°C, the COP can also decline to 2.5. On average, the COP of typical heat pumps has a seasonal variation of about 2.5-2.8. However, there are heat pump models having higher performance in mild climates."

In practice, for adequate capability on a cold winter night (which is when heating is most needed) at -5C, a COP of 2.5 is the best that is likely.

Figures of 4 are 'salesman speak' and will not be achieved under conditions when heat is most needed.

I am seeing figures above 4 in the winter (not myself of course) on some of the tube testers. Lots of detail. I appreciate its not -5 but here that sort of figure is very rare. 

 

[JohnfromUK]

9 minutes ago, Yellow Bear said:

I had a thought that the new"green" refrigerants may have improved this.

You may be right, but I don't believe it has changed much.

[JohnfromUK]

10 minutes ago, oowee said:

I am seeing figures above 4 in the winter (not myself of course) on some of the tube testers. Lots of detail. I appreciate its not -5 but here that sort of figure is very rare. 

Well - he is clearly pleased and that is good.  However, I think it is fairly 'non typical' for most in the UK - and for the following reasons;

1. He is comparing a heat pump with a very old non condensing gas boiler with small radiators and also believed to have been leaking gas.  A modern condensing boiler running at suitable temperatures to allow proper condensation (i.e. return water below around 50 C) would have been very much better.  I'm also not clear how he works out his COP for his heatpump.  It is easy enough to measure the electricity usage (KWh) but I didn't see any reference to the way in which he measured the KWh coming out?  He appears to believe he is doing a figure well over 4 - which is more than most sites suggest is reasonably achievable.  (see the link I posted above).  My guess is that he is not 'counting' KWhs of input from his solar panels and using the figure from the grid sourced meter only in calculating his COP?
2. His average temperature was almost 8 C in Feb and March.  That is higher than most of the UK.
3. He has obviously done his homework and upgraded the radiator sizes appropriately.  I did that (to a slightly lesser extent as I was looking for best efficiency from a condensing gas boiler) and used a model with 55 - 60 flow and 35 - 40 return.  It does give a comfortable heat free from hot and cold spots, but it does need a lot of work (I was replacing the whole system anyway).  I think many heat pump 'conversion' systems 'fail' because this is not done.

There is no doubt that a heat pump can work if done right and in a suitable building.  However - many UK houses are not suitable and do not lend themselves to being 'upgraded' easily.  Also I suspect many UK heat pumps are not properly sized and installed.  When I looked at this for my house a few years ago, it was clear that whilst some experts knew their subject (and in effect told me not to bother with my old listed building constraints unless I had a LOT of money to waste), others said 'no problem', really you are just replacing an old boiler with a new boiler ......... which is of course nonsense.

Also - whilst a heat pump can work if done right, whether it will be economic with the current prices of gas and electricity is questionable if you add in maintenance, installation (which may well need to include an upgraded electricity supply which may not be available at present) and expected life.

[oowee]

1 hour ago, JohnfromUK said:

Well - he is clearly pleased and that is good.  However, I think it is fairly 'non typical' for most in the UK - and for the following reasons;

1. He is comparing a heat pump with a very old non condensing gas boiler with small radiators and also believed to have been leaking gas.  A modern condensing boiler running at suitable temperatures to allow proper condensation (i.e. return water below around 50 C) would have been very much better.  I'm also not clear how he works out his COP for his heatpump.  It is easy enough to measure the electricity usage (KWh) but I didn't see any reference to the way in which he measured the KWh coming out?  He appears to believe he is doing a figure well over 4 - which is more than most sites suggest is reasonably achievable.  (see the link I posted above).  My guess is that he is not 'counting' KWhs of input from his solar panels and using the figure from the grid sourced meter only in calculating his COP?
2. His average temperature was almost 8 C in Feb and March.  That is higher than most of the UK.
3. He has obviously done his homework and upgraded the radiator sizes appropriately.  I did that (to a slightly lesser extent as I was looking for best efficiency from a condensing gas boiler) and used a model with 55 - 60 flow and 35 - 40 return.  It does give a comfortable heat free from hot and cold spots, but it does need a lot of work (I was replacing the whole system anyway).  I think many heat pump 'conversion' systems 'fail' because this is not done.

There is no doubt that a heat pump can work if done right and in a suitable building.  However - many UK houses are not suitable and do not lend themselves to being 'upgraded' easily.  Also I suspect many UK heat pumps are not properly sized and installed.  When I looked at this for my house a few years ago, it was clear that whilst some experts knew their subject (and in effect told me not to bother with my old listed building constraints unless I had a LOT of money to waste), others said 'no problem', really you are just replacing an old boiler with a new boiler ......... which is of course nonsense.

Also - whilst a heat pump can work if done right, whether it will be economic with the current prices of gas and electricity is questionable if you add in maintenance, installation (which may well need to include an upgraded electricity supply which may not be available at present) and expected life.

👍 it's going to be interesting this new house if we get it 🤞.