Heat pumps on the rise after Minnesota passes new energy law

Started by rcjordan, July 10, 2021, 12:46:12 PM

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rcjordan

>straight elec heating

That's the dirty little secret of the great majority of air-to-air heat pumps ...they have big auxiliary straight elec heat strips in the interior ducts.  These strips come on when conditions aren't ideal, or the start-up air is too cold.  In many homes, the auxiliary strips run a lot.

I'm not trying to be negative about the prospects for northern/colder climes, but I get the general feeling that the government & media are glossing over the failings (in desperation?).   Here,when our older legacy homes started switching to heap pumps in the 80-90s my friend in the hvac trade told me that he was busy UNinstalling new air-to-air units. He developed a policy of not installing for anyone over 65-70. "I'm just going to end up taking it out. Too cold & drafty."

Proceed with caution.  There have been some advances and higher SEER, but I don't think the current tech is the final solution.

Rupert

They can work in the UK, if in a location that is generally cool and damp, but rarely freezing.

we have one.... Expensive to install, but generally nice to have in the house. (Saves £1000 p.a on heating over the previous  bottled gas, and I have had it a few years now)
... Make sure you live before you die.

ergophobe

>> I cannot imagine why you would have one somewhere that cold

We have a moderate climate here. Maybe 15 nights per year below 20 degrees Farenheit (-7C). The original article that started this thread was about MN. Northern MN must at least have 100 nights a year that cold. There are stretches of 10 days where it won't get above 0F/-20C. I've experienced days where the *high* for the day was -20F/-30C

So I wouldn't call us "that cold" in the grand scheme of things. If it can't work where we are, it can't work for much of the US and basically none of Canada.

rcjordan

UK: More from the Telegraph;

'However, in a hydrogen strategy unveiled last month, officials said the Government would also explore "enabling or requiring" new natural gas boilers to be "easily convertible to use hydrogen" by 2026. This could apply to new boilers fitted in existing homes.'

Gas boiler ban: a comprehensive guide to what you'll pay and when it comes into effect
https://www.telegraph.co.uk/money/consumer-affairs/gas-boiler-ban-uk-2035-replace-heat-pumps-guide-cost/

Rupert

QuoteSo I wouldn't call us "that cold" in the grand scheme of things. If it can't work where we are, it can't work for much of the US and basically none of Canada.

And I think thats probably right, it wont.

https://flowingdata.com/2021/02/17/low-temperatures-map-of-the-united-states/

And no idea how accurate this is, but it reflects my experience:
https://www.estesair.com/blog/at-what-temperature-do-heat-pumps-become-ineffective/

TLTR... you need a back up heating.

I am sure there will be someone who has worked it out. Air source I would guess would be of marginal benefit anywhere it goes below zero for long. Just because it simply does not work.  There is a point where you could potentially use more energy defrosting than you do for straight heating.

I would think ground source will still work, but that depends on how deep you can go.  I was discussing this with my sister in law who lives just outside Granton on Spey in Scotland, and she thinks they can easily dig below the frost... It needs to be.


Therefore I would be surprised if many in Canada can get air source working well.
... Make sure you live before you die.

rcjordan

>she thinks they can easily dig below the frost... It needs to be.

...And, unless you are doing a closed loop -usually requiring multiple wells on the installations around here-- you have a helluva lot of discharge to get rid of.  IIRC, it averages 3 US gallons per ton per minute of runtime --so my 5 ton unit is discharging 15 gallons a minute (a stream about as big as your wrist).  Excessive discharge has caused many governments to outlaw discharging it into a ditch, storm sewer, or sewage system.

Rupert

Quoteyou have a helluva lot of discharge to get rid of.

Interesting, the the ones I have come across here have been closed look, I assumed it was the law, it might well be in the UK.

come to think of it discharging anything into a water course is controlled.
... Make sure you live before you die.

rcjordan


rcjordan

8% of EU population unable to keep home adequately warm: the largest share of people saying that they were unable to keep their home adequately warm were in Bulgaria (27%), followed by Lithuania (23%), Cyprus (21%), and Portugal and Greece (both with 17%).

https://old.reddit.com/r/europe/comments/qn59oo/8_of_eu_population_unable_to_keep_home_adequately/


This says 5.9% for UK in 2019
https://www.statista.com/chart/amp/16859/share-of-the-population-who-cannot-keep-their-home-adequately-warm/

rcjordan


ergophobe

>> Six reasons

Here's a window mount in an apartment in Manhattan
https://www.youtube.com/watch?v=GuM2ePzSCQs

If you have slider windows, that will be a much bigger challenge


rcjordan

>mines

"Warmed by natural geological processes, the water they pumped to the surface was a pleasant 15C (59F)"

That's the temperature of the ground water here along the coast, considered to be perfect for geothermal heat pumps.


rcjordan

Charity bosses and poverty campaigners have written to Boris Johnson demanding home insulation and heat pumps for people on low incomes, and a windfall tax on fossil fuel companies to fund emergency support on energy bills for vulnerable people. | The Guardian

https://www.theguardian.com/money/2022/jan/14/fund-home-insulation-and-heat-pumps-for-people-on-low-incomes-pm-urged

rcjordan

Applies to Minnesota, too.

"Some have questioned whether heat pumps are appropriate for rural homes at all. Properties in the countryside tend to have poorer insulation than urban houses, making heat pumps less efficient. More than seven times the proportion of rural homes are rated F or G for energy efficiency, the lowest grades, than urban dwellings."

UK: Millions of rural homes forced into expensive eco upgrades
https://www.telegraph.co.uk/money/consumer-affairs/millions-rural-homes-forced-expensive-eco-upgrades/