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Harnessing America's heat pump moment

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Re: Harnessing America's heat pump moment

#531

Post by kragen »

Marsymars wrote: post #528
kragen wrote: post #521

Earlier quoted context omitted.

Either that or solar panels, yeah. I mean it sounds like US utilities are doing a pretty bad job of delivering the unprecedentedly cheap solar power of the last three years to their customers in any case. They're still acting like we're in an energy crisis! So you have to install the modules yourself.

A normal solar panel install wouldn't let me move to resistive heating regardless of size, my house simply isn't serviced with enough amperage. My gas furnace is 100k BTU give-or-take, so I'd need >100 amps for heating alone.

Yes, 100kBTU/hour, which I assume is what you mean, is 29kW, which would be 133 amps at 220 volts, or 610 amps at 48 volts. But solar only supplies power intermittently; you'd need to draw much more power than that when the sun was shining to blast your mansion with 29 scorching kilowatts around the clock. Maybe 100kW, about 2000 amps at 48 volts. For that you'd need ten parallel #0 wires (8.3-mm-diameter copper bars) or the equivalent amount of copper divided among more wires. If it's running four stories from the parapets of your sprawling castle down to the physical plant in the basement, say 16 meters because of all the vaulted ceilings, we're talking about 160 meters of #0 wire, 76 kg of copper.

That's US$833 of copper, and probably US$2000 worth of wire, but it's also US$12000 of solar modules at current international wholesale prices. So the wiring is kind of the least of your worries!

But there's no need to get 2000-amp service from the electrical utility.

Re: Harnessing America's heat pump moment

#532

Post by kragen »

darth_avocado wrote: post #236
kragen wrote: post #151

Earlier quoted context omitted.

Okay but US$5k for half a day of work? It would have been faster if the guy had had his own ladder instead of us moving my desk so he could stand on it to work. (He's bought one since then.)

Homes in the US are much bigger and more than just installing a mini split. You need to factor that in.

My house has six rooms, but the 3400-watt heat pump is only enough to heat two of them. If it costs tens of thousands of dollars in the US, say US$25000, you would expect the resulting installation to be able to heat or cool about 200 rooms rather than 2, producing 340 kilowatts of heat output (1.2 million BTU per hour) and consuming 94 kilowatts of electrical power (430 amps at 220 volts). Indeed, because houses gain and lose heat only through their surfaces, you'd expect the 100× bigger US$25000 heat pump installation to be able to heat or cool a 2000-room building rather than merely 200.

Most houses in the US have less than 20 rooms, let alone 200 or 2000, so it's not mostly because houses are bigger.

Re: Harnessing America's heat pump moment

#533

Post by dns_snek »

glxxyz wrote: post #443
dns_snek wrote: post #381

Earlier quoted context omitted.

> Net metering lets me 'store' excess from summer and use it in winter FYI net metering is unsustainable for the grid and policies will probably change (reducing rates for energy, increasing rates for delivery fees to offset the "freebies") as soon as adoption reaches a critical mass.

I’m not sure what you mean by ‘unsustainable’ nor ‘critical mass’ here. Of course not everyone can net meter- on a sunny but mild day with no-one using A/C nor heating and everyone contributing back to the grid it doesn’t work. My local utility is well aware of that, applications for permits to net meter have to be made, and only a fraction (something like 15%) of properties in each area can net meter. Also the gover…

Sorry, I should've been more specific, I can explain.

> My local utility is well aware of that, applications for permits to net meter have to be made, and only a fraction (something like 15%) of properties in each area can net meter.

Okay, that changes things. The way it worked here is that anyone in the country could install solar and get grandfathered into net metering (perpetually), and then at a certain point they decided to cut it off completely. So you have people from before with who have net metering, and anyone installing it later doesn't have it.

People would install 10-20kW worth of solar, overproduced massive amounts of energy in the summer and then in coldest part of winter (with heat pump COP dropping below 2), people expected to draw 4-10kW of power for heating and pay close to nothing all year round.

The government decided that this was unsustainable so they changed the distribution rates. In effect anyone who doesn't have solar pays roughly the same as they did before, but anyone who has net metering pays substantially more than they thought they would when they signed up.

Ultimately I think this is fair but many people felt cheated by this change. I'm assuming the same could happen elsewhere so I wanted to warn others who might be looking at net-metering deals that look "too good to be true".

Re: Harnessing America's heat pump moment

#534

Post by dns_snek »

PaulDavisThe1st wrote: post #461
dns_snek wrote: post #381

Earlier quoted context omitted.

> Net metering lets me 'store' excess from summer and use it in winter FYI net metering is unsustainable for the grid and policies will probably change (reducing rates for energy, increasing rates for delivery fees to offset the "freebies") as soon as adoption reaches a critical mass.

"All" it needs to be sustainable is a massive investment in storage systems (BESS, and/or others).

You can't store energy year-round. I explained the situation in more detail in a sibling comment but the tl;dr is that people expected to run net-metering households expected to run their brand new heat pumps full tilt in the winter for ~free, the economic reality disagreed, and rates were changed to reflect that.

Re: Harnessing America's heat pump moment

#535

Post by dns_snek »

theoreticalmal wrote: post #505
dns_snek wrote: post #381

Earlier quoted context omitted.

> Net metering lets me 'store' excess from summer and use it in winter FYI net metering is unsustainable for the grid and policies will probably change (reducing rates for energy, increasing rates for delivery fees to offset the "freebies") as soon as adoption reaches a critical mass.

What is an electrical delivery fee?

I meant distribution. Our electrical bill roughly consists of: energy production (per kWh) and distribution fee (per kWh). When you're using energy you accumulated through net metering, the "energy production" portion is free, but you still pay the full rate for distribution.

At some point our previous system became unsustainable and they were forced to rebalance the rates and those who have solar panels with net metering now pay significantly more than they expected they would. I explained in more detail in a sibling comment.

Re: Harnessing America's heat pump moment

#536

Post by monssooon »

otsegony wrote: post #385
monssooon wrote: post #297

Question: I have just bought house and deciding heatpump vs oil. We have an autistic person in the house hold that is very sensitive to high frequency noises and perpetual sounds in general. He is used to an oil furnace turning on and of. I fear for sound pollution from a heat pump. Will anyone share their experiences with this? Even just a shuttle humming would be a disaster for our spectrum case. Can we get a compl…

I don’t know whether you can get a completley silent unit, but I can say that our Mitsubishi heat pump does make a high pitched sound while running. Although I am used to it now, I found it annoying until I got used to it. It is very different than the intermittent low pitched rumble of my oil boiler.

Thanks. Yeah I heard others say the same. And that the sound can increase as the system gets older...

Re: Harnessing America's heat pump moment

#537

Post by reverendjames »

danielsju6 wrote: post #148

Maybe I have scar tissue from COVID prices but $20k to install a ductless heat pump vs. a $200 to throw a window A/C in or $700 for a portable heat pump. While I get that these heat pumps are better for the environment and much more efficient it's a last mile issue. The installers charge an arm and a leg and I'm not hurting enough to self install. I'm hoping the window heat pumps that just run off mains will be avail…

I live in Asia and I'm in charge of air conditioning at my company. A ductless A/c is approximately $1,200 installed. $20k? You should put a split unit in each room. If one breaks, go sleep in the other room. I have 6 of them installed in my apartment.

Re: Harnessing America's heat pump moment

#538

Post by matwood »

Marsymars wrote: post #457
matwood wrote: post #380

I love heat pumps. Had one in my house in the southern US and am about to put one in my house in the EU. I also recently bought a heat pump dryer, also great. Very gentle on clothes, doesn’t need a vent, or the high power plug - just a drain like a washer.

I'm planning on getting a heat pump dryer, but 3x the price (in Canada) means a long break-even.

Yikes. The LG one I bought in the EU was just a little more than a similar sized hot air LG one I had bought in the US a couple of years ago.

Re: Harnessing America's heat pump moment

#539

Post by alextingle »

mattmaroon wrote: post #418
glxxyz wrote: post #219

Earlier quoted context omitted.

People told me that, but I did the calculations myself and the impact on my energy bills is real. Net metering is essential though, so not everyone can do it. Compared to say SoCal I generate 2/3 as much per year, much less evenly- a lot more in summer than winter, whereas further south there's less variation year round. Cooler temperatures improve solar panel efficiency too. There are online solar potential calculat…

Right, but you have to compare it to the opportunity cost of the money. A solar panel is an annuity. There is a one time sunk cost for a relatively consistent, long-term payout. If I put $100 into the stock market in approximately seven years I will have $200. If I put $100 into solar panels, in 10 or 15 years, I will have $100 worth of savings. Financially, it is not much better than just putting it under a mattress…

I see it as insuring myself against electricity price rises. If it's a roughly neutral cost today, but saves me a lot if electricity prices double or triple, then that's a good deal.

Re: Harnessing America's heat pump moment

#540

Post by [deleted] »

danans wrote: post #409
SoftTalker wrote: post #401

Earlier quoted context omitted.

Which is weird because they are quite ugly, both inside and outside.

Compared to a conventional A/C compressor (which they replace), heat pump compressors are much smaller, quieter, and less ugly. As for the indoor units, they can either be the "ugly" ones (the indoor head units visible on the wall), recessed "cassettes", or they can use traditional A/C air handlers in a utility room to distribute conditioned air via existing duct-runs and registers. There are also companies like Quil…

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