Heat pump disappointment for climate-minded Massachusetts state senator • Hacker News Board

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#61

Post by hcknwscommenter » Mon, Apr 10, 2023, 1:37 PM UTC

phpisthebest wrote: post #6

Weatebob wrote: post #5

Earlier quoted context omitted.

I would agree with you if that person would have mentioned research paper and not just some very weak anecdotal evidence. I find it very weird that their heat pump leaked and the efficiency is only at 150%. It's not clear at all if this is an crazy outlier or reality. IF this is not just an outlier than the next proper step from him would be to get the ball rolling with the right people to investigate the status quie…

Heat Pump efficiency is inversely linked to outside air temp, the colder it is outside the less efficient the heat pump is as there is less heat energy to extract from the outside to "pump" into the inside... Fixing is called physics... I am not sure magic words on a page (regulation) will "fix" physics....

It's really difficult to understand what is going on with this politician's heat pump though because we are lacking a lot of basic information. A high quality minisplit system should top out at a COP of over 3.5 and be above 2 down to single digit F temperatures. E.g., https://www.mitsubishitechinfo.ca/sites/default/files/SB_PVA... has a COP of 2.17 at 5F. It seems like there is more to the story. A small duct/high velocity system could perform that poorly, but without the details it's just hard to tell. Most folks with normal ducting or ductless heat pump systems should realize much better efficiency than this guy is getting.

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#62

Post by tcfhgj » Mon, Apr 10, 2023, 1:37 PM UTC

osigurdson wrote: post #44

tcfhgj wrote: post #22

Earlier quoted context omitted.

you are better of adding with a gas plant to the grid, which can be up to 84% efficient (if you reuse the heat generated by the turbine as well) https://en.wikipedia.org/wiki/Combined_cycle_power_plant

Up to 64% as stated in the article. The 84% efficiency statement is in reference to the theoretical efficiency of a Carnot cycle.

64% for the turbine only

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#63

Post by throwaway4aday » Mon, Apr 10, 2023, 1:42 PM UTC

endisneigh wrote: post #59

throwaway4aday wrote: post #41

Earlier quoted context omitted.

If you have hydronic heating anyways then why not get a wood fired boiler? They're extremely common where I am. Why would you need to store the heat? A wood fire isn't instant on but it doesn't take that long either plus you get the heat from the stove itself well before the baseboards heat up.

I have a pretty high efficiency tankless boiler so it would be expensive and wasteful to switch at this point. It is possible to buy a wood fired boiler and hook it up to the house to supplement the tankless but I'm skeptical that makes financial sense.

I'm a bit confused since I thought you were talking about hooking up a wood fired furnace of some type. Putting a solid fuel boiler in line with an existing system is pretty common and doesn't have any impact on the system as a whole efficiency wise except for a tiny bit of heat lost to the length of pipe in the boiler when it's not in use but if you don't mind turning valves on and off you can avoid that with some simple plumbing. When I say boiler I'm talking about the heating part of the unit btw, the tank itself is generally separate if you have one at all.

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#64

Post by nkurz » Mon, Apr 10, 2023, 1:43 PM UTC

> I do not fault the particular pump that we bought or our installers who were careful and professional.

I feel like the author may be letting the installers off too easily here. It seems like there are two main possibilities: either no one understands how heat pumps actually work in the real world and none of them meet their claimed efficiencies (possible, but in my estimation not that likely) or the heat pumps he has installed are unsuited for their purpose (or badly installed). I'm inclined to suspect that he was sold the wrong heat pumps.

Confirming this suspicion, in an earlier post (https://willbrownsberger.com/our-heat-pump-experience/#comme...) he gives the specs for his heat pumps. I don't know this particular model, but a commenter after him claims they are not the sort of "Cold Climate Heat Pumps" that would be appropriate for Massachusetts. Since this matches the symptoms (adequate heat production but low efficiency) I'm guessing this is the real issue here.

I think heat pumps are a great technology, but worry there is going to be a backlash against them unless we can rein in the hype. And something is has gone really wrong if local installers can't be trusted to install a heat pump that is appropriate for the climate they are being installed in. Maybe the best thing he can do as a Massachusetts state senator is to enact more stringent laws preventing the installation of non-cold-climate heat pumps in Massachusetts so others don't suffer the disappointment that he did!

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#65

Post by NDizzle » Mon, Apr 10, 2023, 1:44 PM UTC

tcfhgj wrote: post #20

NDizzle wrote: post #13

Earlier quoted context omitted.

No, it works exactly like solar does. The companies say one thing, but reality doesn't match up. It doesn't matter how careful an installation is.

Why not? The real heating demand can be observed up front and with the typical (or even exact) weather you can easily determine the efficiency of the heat pump. Yeah expect some inaccuracies, but not this huge

My weather person can't even predict what Thursday is going to do. You want accurate predictions for all of winter? That's why I mentioned solar. It's the same, but with sunlight.

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#66

Post by nkurz » Mon, Apr 10, 2023, 1:48 PM UTC

hcknwscommenter wrote: post #61

phpisthebest wrote: post #6

Earlier quoted context omitted.

Heat Pump efficiency is inversely linked to outside air temp, the colder it is outside the less efficient the heat pump is as there is less heat energy to extract from the outside to "pump" into the inside... Fixing is called physics... I am not sure magic words on a page (regulation) will "fix" physics....

It's really difficult to understand what is going on with this politician's heat pump though because we are lacking a lot of basic information. A high quality minisplit system should top out at a COP of over 3.5 and be above 2 down to single digit F temperatures. E.g., https://www.mitsubishitechinfo.ca/sites/default/files/SB_PVA... has a COP of 2.17 at 5F. It seems like there is more to the story. A small duct/high v…

Elsewhere he says that his heat pumps are two Daikin RJQ18TAVJUA:https://ashp.neep.org/#!/product/56878/7/25000///0.

Much of the other information is probably available elsewhere on his site: https://willbrownsberger.com/heat-pumps/

As I mention in another comment, I think the base of the problem is that the heat pumps he has installed are simply inappropriate for his climate.

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#67

Post by ab_goat » Mon, Apr 10, 2023, 1:50 PM UTC

jojobas wrote: post #43

ab_goat wrote: post #39

Brownberger seems to miss the key fact that you can't run a gas heating system on renewable energy. Just as in switching to an EV isn't going to make things significantly better, switching your heating to heat pump isn't either: Some basic tips from a fellow Bay Stater: 1. Any new or replacement mechanicals should be use heat pumps (water heater too) 2. Make sure your house is well-insulated to get the best bang for…

Is net metering available anywhere at all? Where I am it's long gone, and I hear in some areas they charge you to use your excess energy.

Net metering is still very much available in MA.

https://www.mass.gov/guides/net-metering-guide

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#68

Post by anonymousab » Mon, Apr 10, 2023, 1:53 PM UTC

nkurz wrote: post #64

> I do not fault the particular pump that we bought or our installers who were careful and professional. I feel like the author may be letting the installers off too easily here. It seems like there are two main possibilities: either no one understands how heat pumps actually work in the real world and none of them meet their claimed efficiencies (possible, but in my estimation not that likely) or the heat pumps he h…

One thing I am learning in doing research for local installers and HVAC companies is that you can't really trust any installer to do it right. Even the highest reviewed company will have tons of monthly reviews about wrongly installed equipment or bad advice to customers.

Like buying any major appliance, unless you shell out a commercial fee for a commercial product and contract, you're just gonna be rolling the dice. You can do it yourself but the heat pump unit itself may still vary dramatically from sales specs.

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#69

Post by post_break » Mon, Apr 10, 2023, 1:54 PM UTC

detourdog wrote: post #52

ct0 wrote: post #15

Earlier quoted context omitted.

In your experience, does your heat pump dryer actually dry in a similar amount of time to a conventional electric dryer?

I have installed condensate dryers which are actually more efficient than heat pump dryers but take a couple of hours to dry. They don't need to be vented to the outside.

My heat pump dryer doesn't vent and captures the water to a tank or pumps it down the drain.

Re: Heat pump disappointment for climate-minded Massachusetts state senator

#70

Post by endisneigh » Mon, Apr 10, 2023, 2:00 PM UTC

throwaway4aday wrote: post #63

endisneigh wrote: post #59

Earlier quoted context omitted.

I have a pretty high efficiency tankless boiler so it would be expensive and wasteful to switch at this point. It is possible to buy a wood fired boiler and hook it up to the house to supplement the tankless but I'm skeptical that makes financial sense.

I'm a bit confused since I thought you were talking about hooking up a wood fired furnace of some type. Putting a solid fuel boiler in line with an existing system is pretty common and doesn't have any impact on the system as a whole efficiency wise except for a tiny bit of heat lost to the length of pipe in the boiler when it's not in use but if you don't mind turning valves on and off you can avoid that with some s…

my understanding is that a wood furnace is meant to be used with wood pellets or properly seasoned wood. using random rotting decaying dead wood outside probably wouldn't be a great idea - I'll need to look into it more.