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

knowablemagazine.org

141–150 of 494 posts

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

#141

Earlier quoted context omitted.

How much electricity was the fan using? :)

Indeed, sounds like a problem with the fan. My 3000sf house uses 1100W for the fan, and about 4000W for the heat pump. I expect converting to mini-splits would increase, not decrease my overall power usage.

700W for the gas ducted heater fan. That’s the steady state energy consumption of all 3 units heat pumps running simultaneously. This is a small house of 100 square metres/1100 square feet.

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

#142

Earlier quoted context omitted.

How much electricity was the fan using? :)

Indeed, sounds like a problem with the fan. My 3000sf house uses 1100W for the fan, and about 4000W for the heat pump. I expect converting to mini-splits would increase, not decrease my overall power usage.

Obviously a new EC fan will be more efficient than a 20 year old AC fan, but I’m talking about a retrofit application here.

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

#143
post #134

Earlier quoted context omitted.

Agree, ducts are wonderful! If you don't have ducts, go ductless for sure.

Am I crazy, or are those two sentences completely contradictory?

I thought it was a joke. If you don't have ducts, you are by definition ductless. So that's how you must go.

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

#144
> owners of drafty homes may need to take on the added cost of insulation when installing a heat pump

Installing good insulation is also really important even if you're not using heat pumps! With bad insulation, you're wasting energy no matter what technology you're using.

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

#145
post #69
post #57

Earlier quoted context omitted.

Different geographies have different requirements. You're not likely to need to face a week or more of no power after an ice storm in -10'C in Ireland.

We don't have power outages after ice storms. Temperatures of -10°C are regularly in Scandinavia as well as in Austria, Swiss and Germany. We are living in a developed world with working infrastructure. Power outages happens only by accident like when an US helicopter tries weird landings: https://www-abendzeitung--muenchen-de.translate.goog/bayern/...

> We are living in a developed world with working infrastructure.

You're welcome, we bombed all your infrastructure into oblivion about 80 years ago, now it's all new! And also, your country is quite a lot denser than North America, so you can bury every single power cable (though you don't, obviously) and if you think -10C is cold, just wait until you see what much of North America experiences during the winter.

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

#146

Earlier quoted context omitted.

> Ducts are dead. Ducted heatpumps are a thing here in NZ and make sense to me, not that I have used one. The heatpump sits in the roof and air is pushed into three or so rooms through ducts. If building a new house I think ducts would be the way to go.

You have to think carefully about where you run the ducts. They can be a huge source of energy loss. 40% is the number quoted by the EPA. Most roofs in Australia still aren’t sealed. The air barrier and insulation barrier is the ceiling. The roof space itself is not insulated, so the ducts are exposed to extreme temperatures, thus destroying the efficiency. Here is just one article on it: https://newenergythinking.co…

Why wouldn't you just lay insulation on the ducts, same as you do with water pipes?

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

#147
post #132

Earlier quoted context omitted.

> Ducts are dead. Ducts are still needed to circulate air, especially if you want to remove stale air (e.g., bathrooms, kitchen) and bring in (filtered) fresh air (to bedrooms).

Not being snarky but why don't you just open the window for that? I have a CO2 detector that I believe is a reasonable proxy for stale air. When it goes above 1000 I simply open the windows. By the time I remember to close the windows the reading is almost always below 500.

A ventilation system allows you to filter (not a luxury when you live in a big city, where you will be breathing pollutants otherwise) or perform some thermal magic if the outside air is very cold (or very warm), by running the outflow and inflow pipes really close to each other.

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

#148
post #132

Earlier quoted context omitted.

> Ducts are dead. Ducts are still needed to circulate air, especially if you want to remove stale air (e.g., bathrooms, kitchen) and bring in (filtered) fresh air (to bedrooms).

Not being snarky but why don't you just open the window for that? I have a CO2 detector that I believe is a reasonable proxy for stale air. When it goes above 1000 I simply open the windows. By the time I remember to close the windows the reading is almost always below 500.

Where I live, it can get very cold. Not always very efficient to open windows for 5 months out of the year.

A great option for keeping CO2 levels down in a house is with an HRV (or ERV) [1] that will heat the fresh air coming in to cycle it throughout the house.

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

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

#149
post #132

Earlier quoted context omitted.

> Ducts are dead. Ducts are still needed to circulate air, especially if you want to remove stale air (e.g., bathrooms, kitchen) and bring in (filtered) fresh air (to bedrooms).

Not being snarky but why don't you just open the window for that? I have a CO2 detector that I believe is a reasonable proxy for stale air. When it goes above 1000 I simply open the windows. By the time I remember to close the windows the reading is almost always below 500.

On the west coasts of Canada (BC) we've had insane forest fires the past few years and you 100% want to filter the internal air when it's extremely unhealthy outside. We're talking air quality index in the 300+ range or off the charts at times [1]. Plus, we've had these heat domes were it's in the high 30+ and just gross inside, where you really want to open the windows, but you're letting in tons of pollution. Basically, you need to cool off and filter the air at the same time.

[1] https://www.airnow.gov/aqi/aqi-basics/

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

#150
post #20

Earlier quoted context omitted.

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 ?

My parents built a new home a couple years ago. The property had a well despite being on city water. They have other homes with ground source heat pumps. When asking the geothermal contractor if they could use the same well borehole, the contractor said why don’t we just circulate the water and not bother the existing well. So that’s what they do - their geothermal system uses the well water, circulates it through th…

This is fascinating! Is it possible to do this while utilizing the well for drinking water? I would assume so - it would just go through the condenser to exchange heat before being used elsewhere, and less would be pumped back down to the well?
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