Heat pumps of the 1800s are becoming the technology of the future • Hacker News Board

Re: Heat pumps of the 1800s are becoming the technology of the future

#11

Post by IMTDb » Mon, Jan 16, 2023, 4:48 PM UTC

nickpeterson wrote: post #4

Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc. When it’s freezing cold outside, it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated. Someone needs to make a standard for moving heat/cool through all appliances in a house…

In order to cool your refrigerator, the system has to have a place to the put the "hot" it just extracted. And that place is your house itself; your freezers and refrigerators are warming your house and contribute just like the radiators you installed. So the losses are not as big as you expect them; the money you spend on those appliances also lowers your heating bill.

Re: Heat pumps of the 1800s are becoming the technology of the future

#12

Post by zozbot234 » Mon, Jan 16, 2023, 4:51 PM UTC

retrac wrote: post #2

> heat pumps: electrical devices Just to be pedantic, but not exactly. The typical design in a domestic heating unit, or refrigerator is mechanical. A fluid is pumped and cyclically compressed/expanded. While electric motors are usually used, they can be driven by any source of mechanical energy; driven directly by a combustion engine is not too unusual. There are also heat pump cycles that can be driven directly wit…

Strictly speaking you don't need a phase change in the fluid for a viable heat pump; pressure change is enough albeit with worse efficiency. Even something as simple as a Stirling engine with forced circulation of the fluid works as a heat pump.

Re: Heat pumps of the 1800s are becoming the technology of the future

#13

Post by dabeeeenster » Mon, Jan 16, 2023, 4:53 PM UTC

BooneJS wrote: post #3

When will air source heat pumps be ready for service in cold weather climates without gas backup?

Just had a heat pump installed (Vaillant) - at -1 degrees outside I'm getting a COP of > 2.6.

So they are ready.

Re: Heat pumps of the 1800s are becoming the technology of the future

#14

Post by mikewarot » Mon, Jan 16, 2023, 4:54 PM UTC

For our house, a ground loop heat pump would be best. A long slit trench, with the slinky style of coolant loop, in the back yard (away from utilities) could easily handle all our waste heat in the summer and source heat in the winter.

Re: Heat pumps of the 1800s are becoming the technology of the future

#15

Post by jillesvangurp » Mon, Jan 16, 2023, 4:54 PM UTC

nickpeterson wrote: post #4

Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc. When it’s freezing cold outside, it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated. Someone needs to make a standard for moving heat/cool through all appliances in a house…

The good news is that the process of running your fridge moves the heat from the fridge into your home, which in the winter is not such a big problem. Your fridge is just another heat pump. It's a bigger problem in the summer when you are maybe trying to cool your house using air-conditioning and your fridge adds heat to your house to keep the fridge cool. Much less desirable.

Re: Heat pumps of the 1800s are becoming the technology of the future

#16

Post by ghettoCoder » Mon, Jan 16, 2023, 4:54 PM UTC

retrac wrote: post #10

nickpeterson wrote: post #4

Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc. When it’s freezing cold outside, it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated. Someone needs to make a standard for moving heat/cool through all appliances in a house…

> it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated The fridge is simply moving a little of the warmth in your room out of its box, and adding a little more warmth to the room in the process. You lose no heat from the room, which is what matters, really. It would be worse to dump the heat outside! At least in winter. The heat has to be removed…

I always joke that in winter all appliances are 100% efficient (I know they're not). Some look at me funny but the ones who pay the gas bill get usually get it.

Re: Heat pumps of the 1800s are becoming the technology of the future

#17

Post by rpearl » Mon, Jan 16, 2023, 4:57 PM UTC

nickpeterson wrote: post #4

Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc. When it’s freezing cold outside, it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated. Someone needs to make a standard for moving heat/cool through all appliances in a house…

There are heat pump water heaters (I have one; AO Smith HPTU-50N). More expensive up front vs tankless but a lot more efficient.

Re: Heat pumps of the 1800s are becoming the technology of the future

#18

Post by mschuster91 » Mon, Jan 16, 2023, 4:59 PM UTC

nickpeterson wrote: post #4

Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc. When it’s freezing cold outside, it seems crazy that I warm the air of my house and then use electricity to keep the fridge cooler than the air I just heated. Someone needs to make a standard for moving heat/cool through all appliances in a house…

> Why can’t my whole home participate in this technology? It would seem an ok fit for things like freezers, refrigerators, hot water heaters, etc.

At large scale (think like walk-in coolers of supermarkets), this is actually being done in the form of district cooling [1].

> Someone needs to make a standard for moving heat/cool through all appliances in a house…

The problem is that the piping itself and the circulation required are sources of energy loss, and it's hard enough to keep these appliances sealed so they don't leak their coolant - most coolants have insane CO2 equivalent potentials. It's not worth the effort.

[1] https://en.wikipedia.org/wiki/District_cooling

Re: Heat pumps of the 1800s are becoming the technology of the future

#19

Post by jakedata » Mon, Jan 16, 2023, 4:59 PM UTC

In 2017 we installed a very efficient air-source heat pump and solar panels. My electrical utility offers 1:1 buyback of electricity so I am able to build up a credit in the summer and run the heat pump well into the fall and winter on that surplus. The system is sized for cooling the house which means that it is undersized for heating, but during cool fall and spring temperatures it operates satisfactorily as a heat source.

Our fallback is the pre-existing gas boiler which is much simpler, more reliable and able to be powered by a small generator during our all-too-frequent power outages.

If I am still in this home when the current heat pump fails I will seriously consider a ground-source system instead. The ability to operate during an extended power outage is a significant concern and I expect to always retain the gas boiler as a backup.

Re: Heat pumps of the 1800s are becoming the technology of the future

#20

Post by ddalex » Mon, Jan 16, 2023, 5:00 PM UTC

mikewarot wrote: post #14

For our house, a ground loop heat pump would be best. A long slit trench, with the slinky style of coolant loop, in the back yard (away from utilities) could easily handle all our waste heat in the summer and source heat in the winter.

Wouldn't it be cheaper/easier to dig a well, fill it with tubing, and pouring concrete all over? The concrete being the constant-ish temperature heat reservoir ?