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Nine US states are teaming up to accelerate the adoption of heat pumps

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Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#541

Post by zbrozek »

jlawrence6809 wrote: post #504
zbrozek wrote: post #42

Earlier quoted context omitted.

The simplest devices are on or off. If they are grossly oversized they cycle a lot and make homes less comfortable by pushing a huge volume of hot or cold air briefly. Variable speed compressors are better, but blowers may not also be variable speed. So you'll get better efficiency but may still suffer a feeling of draftiness. A properly sized variable speed unit will operate within some optimal band of efficiency an…

When I was shopping for a mini split recently all the models I could find seemed to be variable speed compressor and blowers, unless I was reading something wrong. So maybe this isn't an issue anymore? I oversized mine but wish I went even bigger after a cold snap we just had in the pnw this last winter.

Mini splits are better in this regard than traditional ducted installations.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#542

Post by erikpt-work »

dripton wrote: post #518
jhallenworld wrote: post #425

Earlier quoted context omitted.

The fossil fuel capitalists are so very unhappy about this ban, they are still going on about it in the financial news. I have to say, I love it. Low natural gas prices directly benefit me, and isn't it our gas? The price has certainly come down (look at henry hub chart..), but also winter has not been too cold.. They should ban oil exports next.. (for "national security") Actually export tariffs would be better than…

Export tariffs are actually unconstitutional in the US. https://en.wikipedia.org/wiki/Import-Export_Clause

Looking at that clause, it appears that it's only unconstitutional if the individual states do it. Doesn't say anything about the federal government or Congress. Or am I reading it wrong?

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#543

Post by zbrozek »

lelandbatey wrote: post #449
GloriousKoji wrote: post #193

Earlier quoted context omitted.

I live in the Bay Area California and get electricity from PG&E. I use a minimal amount of electricity and I paid 43 cents/kWh last month. Gas from Costco is $4/gal right now. I have a plugin-hybrid which does 4miles/kwh and 45mpg or in terms of money: 9.3miles/$ on electricity and 11.25gas-miles/$ on gasoline. But maybe you don't actually care about fuel efficiency, then you have an argument that it's cheaper to fue…

> I paid 43 cents/kWh last month Whoooooa ok that makes more sense why folks are complaining; I paid 13 cents/kWh last month, less than 1/3 of what you're talking about. Note for others, paying $0.45/kWh is highly unusual for the US as a whole; see the US Gov published stats on average electricity prices by region which puts the average at ~$0.17/kWh: https://www.bls.gov/regions/midwest/data/averageenergyprices...

Yeah we're getting shafted. Starts at $0.487 and goes up to $0.618 per KWh.

https://www.pge.com/tariffs/assets/pdf/tariffbook/ELEC_SCHED...

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#544

Post by contravariant »

Aloha wrote: post #372
Retric wrote: post #349

Earlier quoted context omitted.

In the continental US you get ~2x the heat from burning natural gas in a combined cycle turbine to run a heat pump than you would from using a high efficiency gas furnace. The market price of electricity vs gas varies quite a bit through time and various distortions of the market. Currently gas is cheap, but you want to compare historical averages when buying something that lasts 15+ years not simply look at current…

I don't think your math adds up. Combined cycle is like at most 70% efficient, subtract 10% of distribution, you end up with 60%. At 50f my 5T heat pump takes 6.6 kWh to generate 50,000 BTU. 6 kWh of energy takes 71cf of gas to make - accounting for transmission and generation losses. 71cf of gas will make 71,000 BTU of heat, assuming an 80% efficiency furnace, that comes out to 56,000 BTU usable. Yes a heat pump wil…

Dear god how do you keep sane with those kinds of units? You're making it so confusing you fail to realise some of your numbers don't quite line up

In sane units:

- 2 m^3 of gas generates 6.6 kWh of electricity

- which generates 14.7 kWh of heat (at some temperature differential).

- The same 2 m^3 of gas generates 20.8 kWh of heat

- of which about 16.4 kWh is usable assuming some losses.

Of course your implied electricity generation is only around 31% efficient, so I'm not sure what that 60% you mention in the beginning is about. The COP you're using is around 2.2, which together with a 60% efficiency for generating electricity would be greater than 1, outstripping anything that's physically possible to achieve with a furnace.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#545

Post by hasbot »

tilwidnk wrote: post #289
readingnews wrote: post #86

I just replaced a furnace... everyone I called for a quote would not touch a heat pump with a 20foot pole, or they wanted prices that were 2X what a separate furnace and AC would cost to install. It was very strange. This is the second home where I had this experience.. basically, they really did not want to install it. I ended up going with gas as no local person would install/warranty a heat pump, or, it was priced…

We've owned three homes, our first one had a heat pump. In Virginia. It generally sucked. It wasn't as good as real A/C in the summer and wasn't as good as gas or electric heat in the winter. I hope to never end up in a place that uses a heat pump.

It may have been low on refrigerant. I'm in Virginia now and most of my neighbors have heat pumps including me. Mine is 17 years old and is definitely low on refrigerant so I use the original baseboard heat instead.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#546

Post by ab_goat »

I converted my small (~1400 sqft) MA log cabin house at 1500' elevation to a heat pump as main heat source in 2017. We also added a 8kW PV system at the same time.

It was a great choice, and we've been net negative since installation.

We also get a lot of passive solar via low angle sun through large windows. I think passive solar in winter is a completely under-appreciated benefit. On sunny days in winter we do not need heat for ~10 hours of the day.

We supplement our heat with a wood stove in very cold weather (< 20ºF). It's not necessary, but brings a cozy warmth.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#547

Post by AnthonyMouse »

s1artibartfast wrote: post #424
colechristensen wrote: post #241

Earlier quoted context omitted.

Utilities cost excesses in California are largely PG&E paying for its liability for causing wildfires in places where people probably shouldn’t live anyway. For example Silicon Valley Power which serves Santa Clara (or something like that) has rates that are literally half as much as PG&E. In Minnesota I’m paying for Xcel Energy’s mistakes in Texas.

People should be able to live wherever they want. That doesn't imply others should have to subsidize them doing so. It is really quite simple. If someone remote wants power, they should secure power and pay for it at a market clearing rate, given the cost and risk to deliver it.

This is something else.

California has wildfires, and climate change has made them worse. Then the people who built their houses in a silly place prone to wildfires watch them burn down. This is becoming a problem as the frequency which with it happens increases, because it can bankrupt fire insurance companies (who then can't pay claims), or make fire insurance there unaffordable and then people don't buy it, their house burns down, and you have angry constituents.

The political solution to this is to put the liability on the power company whenever possible, even though it isn't really their fault. The fire is caused by dry conditions and that wood is going up the first time there is any kind of flame anywhere near it. If it wasn't PG&E it would have been a lightning strike or something else. Having the fires less often can actually make them worse.

But the power company is a deep pocket, so if there is any way to pin the fire on them, that's what everybody wants to do, so that the uninsured people in the fire zone can collect from someone and the currently insured people who are still there don't become unable to afford fire insurance.

Then the power company raises rates on everybody in their service area, including people who don't live in high fire risk areas, because the government has them acting as the fire insurance company, but now you can't cancel your "fire insurance" without turning off your electricity and it also has to be paid by people who didn't build their house in a silly place.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#548

Post by Scoundreller »

twoodfin wrote: post #403
taude wrote: post #393

Earlier quoted context omitted.

Also, doesn't states like MA import a not-insignificant amount of natural gas from elsewhere to convert to electricity? Would like to hear about what's more efficient: direct natural gas heating vs natural gas -> electricity -> heat pump...

Yes, and for nominally climate-driven reasons MA has constrained the construction of pipelines and other facilities that would allow the cheaper delivery of natural gas for cheaper electricity… thus discouraging consumers like me from moving to electrical utilities that would net reduce emissions.

And you have Maine getting in the way of hydroelectricity from Quebec making its way over:

https://www.cbc.ca/news/canada/montreal/hydro-quebec-1.68167...

https://www.hydroquebec.com/projects/appalaches-maine-interc...

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#549

Post by Reason077 »

aero_code wrote: post #435
Aloha wrote: post #372

Earlier quoted context omitted.

I don't think your math adds up. Combined cycle is like at most 70% efficient, subtract 10% of distribution, you end up with 60%. At 50f my 5T heat pump takes 6.6 kWh to generate 50,000 BTU. 6 kWh of energy takes 71cf of gas to make - accounting for transmission and generation losses. 71cf of gas will make 71,000 BTU of heat, assuming an 80% efficiency furnace, that comes out to 56,000 BTU usable. Yes a heat pump wil…

I don't think the numbers are accurate in the quantity of gas. Since kWh and BTU are both units of energy, finding the cf of gas is unnecessary (assuming the efficiency numbers are correct). 1 kWh = 3.6 megajoules and 1 BTU = 1055 joules The 6.6 kWh of the heat pump is 23.76 MJ which is 22,521 BTU of energy. Assuming that the power plant and distribution are 60%, it would take 37,535 BTU of gas to produce (22,521/60%…

> "(Of course, they have drawbacks, like they can leak their refrigerant that causes more of a greenhouse effect than CO2.)"

My heat pump contains 2.1 kg of R32 refrigerant. R32 has a GWP of 675, so that 2.1 kg is the equivalent of 1417 kgs of CO2. (older refrigerants were much worse!)

Heat pumps should never leak their refrigerant during their lifetime, and installers will remove and recycle the refrigerant when servicing or decommissioning systems. But of course, accidents happen, so let's pessimistically assume that 50% of systems installed will eventually leak. In the real world it's hopefully far less than that, but that would mean on average 708 kg CO2e in refrigerant is emitted per system over its lifetime.

On the other hand, heating a typical US home with natural gas emits 2900 kgs of CO2 per year.

I think it's safe to say that the climate impact of refrigerant leaks in modern heat pump systems is minuscule compared to that of the CO2 emitted from natural gas heating.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#550

Post by thoughtstheseus »

Aloha wrote: post #480
smcleod wrote: post #384

Earlier quoted context omitted.

Natural gas won’t stay cheap. It was cheap here in Australia 10 years ago and now it’s so expensive no one can afford to run gas heating and it’s only going up. Now (thankfully) the government has banned the installation of new gas heating and a lot of people are getting rid of gas cooking, hot water heating etc… it’s for the best.

It was cheap 10 years ago because the global price of gas was cheap, its not now.

No such thing as a global gas price. Natural gas pricing is regional as it cannot be easily transported.
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