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Pretty soon, heat pumps will be able to store and distribute heat as needed

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Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#141

Post by Marsymars »

sbierwagen wrote: post #139
Marsymars wrote: post #130

Earlier quoted context omitted.

There are also existing commercially-available residential units (e.g. Ecombi or Steffes) using ceramic bricks that are in the ~450 kJ/kg range.

Note for the confused: Ecombi achieves this by heating the bricks to dramatically higher temperatures using conventional resistive heating elements, thereby storing more energy, even though the specific heat capacity of any ceramic material is dramatically inferior to that of water. But, as a result, Ecombi has a much lower system efficiency than a heat pump, since it's essentially just a space heater pointed at a ro…

Thanks for the notes! I've seen them at other people's homes, but that's about the extent of my knowledge about them. (And I quickly googled a spec sheet to calculate a kJ/kg value.)

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#142

Post by zobzu »

tempestn wrote: post #126
manmal wrote: post #105

Earlier quoted context omitted.

Certainly not gas or oil, which are still cheaper to heat with than heat pumps.

Modern heat pumps are cheaper than oil for heating just about everywhere. They're cheaper than natural gas in most places, unless electricity prices where you live are particularly high.

in CA my natural gas is far cheaper than the heat pump sadly

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#143

Post by BenoitEssiambre »

rekabis wrote: post #2

I would love to see a bus-sized version for year-long temperature moderation. Like, drop house heat into it during the summer so it can re-heat the house over the winter, and pull all the heat out of it by Spring so that it can cool the house over the summer. Bus sized because that amount of thermal mass is bound to take up a lot of space, but capable of being buried so that it doesn’t actually take up property space…

Yeah I always wondered if I ever switched to solar panels, would there be a way to accumulate heat to be used in the Canadian cold months that have little sunlight? The closest I found was electric thermal storage based on heating bricks. They can accumulate more energy than water since they can go to higher temperatures. For example these say they go to 1300°F or 700°C https://steffes.com/ets/roomheater/ . They don't seem to have large models that could heat a house for months however.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#145

Post by npodbielski »

IshKebab wrote: post #99
gwbas1c wrote: post #90

The article omits some critical details: It says this is both a "heat pump" and also "storage" AND says that it will run when electricity is cheap or plentiful. Thus: 1: Where does it pump the heat from? (Or is this not really a "heat pump" and instead is using resistive heating?) 2: How long does it store heat? Is this something that will store heat on a 24-48 hour basis, or will this store heat during the spring /…

1. The device is just storage. It would be paired with an air or ground source heat pump. 2. With good insulation you can easily store heat for a day which is all you need. You're never going to get close to storing summer heat for the winter. That's not impossible but not feasible for something this scale (and not cost effective at any scale). 3. You just heat it up and cool it down. There are no fancy chemical proc…

> With good insulation you can easily store heat for a day which is all you need. You're never going to get close to storing summer heat for the winter. That's not impossible but not feasible for something this scale (and not cost effective at any scale).

This is ground basically. How deep varies but few meters underground you basically have average yearly temperature. You could pump heat from house to the ground to take it out from the ground during winter.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#146

Post by afiori »

dataflow wrote: post #129
esseph wrote: post #117

Earlier quoted context omitted.

Microwave tip: Use the power button to select a lower power level, and cook the food for longer.

Only works adequately if your microwave is the rarer kind that actually lowers the power (inverter), instead of just switching between 100% and 0% repeatedly.

This should depend on the frequency of the switching, if it is every few seconds it should behave sorta the same

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#147

Post by vel0city »

chongli wrote: post #137
vel0city wrote: post #134

Earlier quoted context omitted.

I don't have the fancier inverter style. Setting a power level still works pretty well even though flawed. Drawing out the overall cooking time still manages to get things more evenly heated in the end when you give the food time to distribute the heat throughout the food. Cooking food for 2 minutes at 50% power gives a noticeable difference in average temperature compared to cooking food for 1 minute at 100% power a…

It's funny, because the inverter microwave is actually cheaper to build nowadays. It uses a small switching power supply to generate the needed voltage to run the magnetron at different power levels. The older style duty cycle microwaves use a huge transformer to generate the high voltage, which makes them way heavier and more expensive due to all that copper.

My microwave is over 20 years old and still working fine even with its computerized automatic modes. Modern versions of the product line are inverter based. Whenever this unit fails I'll probably replace it with the modern inverter version. I've used it at friends places, it's quite nice.

It's a GE Profile model FWIW. It seems like a good product line from my experiences. The matching oven has also been a good performer overall.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#148

Post by enaaem »

themafia wrote: post #89
jandrese wrote: post #62

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climate…

> government mandate will force enough demand that manufacturers can enjoy some economies of scale So you want the government to pick winners and you want to do business with a monopoly? This is the opposite of what you would want. If the product saves me money, and it's _actually_ better, I will buy it in a heartbeat. If you're involving the government it's because one of those things isn't true.

Gas infrastructure is expensive to build and maintain. Often times with tax money. What tend to happen in Europe is that they phase out gas by not building gas lines for new development.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#149

Post by serpix »

baggachipz wrote: post #86
gwbas1c wrote: post #84

Earlier quoted context omitted.

You're about 20 years behind. My heat pump is working great at 0F. It's 7 years old.

heat pump for house !== heat pump for hot water

Yes, same thing. Heat pump to heat exchanger. This is over 39 years old tech and in common use around Scandinavia and mainland europe. This is ancient technology.

Re: Pretty soon, heat pumps will be able to store and distribute heat as needed

#150

Post by jcgrillo »

gwbas1c wrote: post #84
jandrese wrote: post #62

I've been keeping an eye on heat pump water heaters for awhile, but right now they mostly make sense in warm climates. The big problem is they're still specialty products and marked up like crazy, but also they tend to use cheap components which makes them loud and prone to failure. If you run A/C for the majority of the year then they pay themselves back reasonably quick, barring early failure, but in colder climate…

You're about 20 years behind. My heat pump is working great at 0F. It's 7 years old.

Mine are in climate zone 6. They're only a couple years old. The coldest temperatures I've run them at so far are -21°F and they kept the house adequately unfrozen. They'll maintain a COP of 2 down to 5°F IIRC. The hot water heater is an 80gal Rheem heat pump unit. No complaints there either. It would be pretty great to have some thermal storage though, temperatures in the dead of winter here are usually above 5°F during the day but drop well below zero at night. Blasting the heat pumps during the day to bank heat for overnight would be far more efficient.
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