High Temperature Air Source Heat Pumps for Domestic Heating

[Clive Brown 1Participant @clivebrown1]

Posted by SillyOldDuffer on 13/04/2021 11:51:31:

Posted by J Hancock on 13/04/2021 11:25:56:

True the wind isn't blowing hard today, but Solar is contributing more than Nuclear, hurrah.

Dave

Ah! but the sun wiil set while nuclear soldiers on.

[Steve Skelton 1Participant @steveskelton1]

Following up on the original post re ASHP:

After many hours of research and trying to contact technical people I got nowhere further forward with this project. I feel that the UK renewables industry is overselling the capabilities of the performance of ASHP's in the UK environment. Not one company would get back to me with real-life performance data on UK installations.

I am now convinced that actual UK performance data is well below that quoted by the manufacturers – who all quote a DIN standard that tests the units in low humidity lab conditions. I believe that the constant icing up of the units, due to the high UK humidity, is what is causing the problems. The air temperatures that we experience in the UK are not the issue I think that as soon as the units form even a small layer of ice on the heat exchanger fins the COP falls off a cliff due to the inability to draw energy from the surrounding air. Ice has a low thermal conductivity??

Anyway, I shall continue to use my LPG boiler (we are out in the country so do not have easy access to natural gas). As it is we use such a small amount – less than 300kg/year.

In terms of the way forward on the climate I think the government should be funding carbon capture research and development. I do not see CO2 levels going down anytime soon and unless something is done to remove it from the air I feel the doom merchants may be right regarding our future. An interesting, although worrying thing is that in 1950 our co2 in air was about 300ppm it is now above 400ppm. According to research and ice core samples of air going back more than 800,000 years CO2 levels were always below this 300ppm level.

For info see: https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide

There are many other independent reports supporting this level of CO2 increase.

Makes me think that capturing and reducing the CO2 in the air should be as high a priority as trying to reduce emissions.

[J HancockParticipant @jhancock95746]

My thoughts exactly SS , the problem is, there appears to be no-one ' in authority ' for the past three decades

who has the slightest interest in a practical solution using coal.

[BazyleParticipant @bazyle]

Steve, have you asked for information on the Navitron forum? About 10 years ago when no suitable data was available someone on there publshed a year's real data from his solar system of daily output, so you could see the good and bad days in winter, and how things gradually improved in spring.
Chances are someone there is doing some detailed monitoring of his ASHP now.

[Martin ConnellyParticipant @martinconnelly55370]

The outside units are able to detect ice build up and go into de-icing mode. Mine iced up once this winter when I left it on overnight due to the predicted low temperatures with wintry showers and you could hear the change in the pump when it went into de-ice mode at about 07:30. Returned to normal after about 10 minutes. I also have an app on my phone that controls the unit so I can set schedules for how I want it to work. There is also an energy consumption report that does days, weeks and years so you can compare day to day or year to year as well as telling you what the consumption of electricity has been in the selected period. Yesterday it used 13.8kWh. Last week it used 117.3kWh. I do not have a full year's figure yet. The highest month was January when it used 855.9kWh, by March it was down to 508.7kWh. I use the scheduling to switch it on at a high temperature in the morning when off peak rates apply then back the temperature back down when normal electricity rates apply. This was the only source of heat used, about 170m², no back up required but I do have 2 electric towel rails. Hope these figures help.

Martin C

Edited By Martin Connelly on 13/04/2021 14:02:33

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