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My new dryer is a heat pump. Uses less than half the energy my previous one did. It does take longer to dry clothes, but it's much gentler on the clothes so it'

My new dryer is a heat pump. Uses less than half the energy my previous one did. It does take longer to dry clothes, but it's much gentler on the clothes so it's a perfect trade off for me. I'd love to do a heat pump like this for the house but there is so much oil pipeline around me and there's no way a truck with a pile driver can reach my back yard.

dzhiurgis 4y ago
Hot water cylinders can have heatpumps too! Wish we found a solid way yo harvest heat from waste water. So much energy is wasted on showers - similar to EV driving at highway speeds.
- throwaway4220 4y ago
  https://en.m.wikipedia.org/wiki/Countercurrent_exchange https://en.m.wikipedia.org/wiki/Countercurrent_exchange A lot of mammals do this including humans. Don’t know if there’s a drop in plumbing shower solution.
- bombcar 4y ago
  We do it. It’s not yet economically worth it but I’ve seen installs. I can’t find it but I saw one that was designed to let a massive shower run continuously with very little heat loss - the water coming out the end of the drain was as cold as the inlet water from the main. https://en.m.wikipedia.org/wiki/Water_heat_recycling https://en.m.wikipedia.org/wiki/Water_heat_recycling
- theluketaylor 4y ago
  drain water heat recovery is already a thing. It's code for new builds in British Columbia, Canada. It's only expensive due to the amount of copper. The actual install has no moving parts and is completely passive. https://www.nrcan.gc.ca/energy/products/categories/water-heaters/14568 https://www.nrcan.gc.ca/energy/products/categories/water-hea...
  - dzhiurgis 4y ago
    What efficiency are these? Brainstormed this a bit and feels like shower cabins (pretty popular over NE Europe) should have such system as standalone... As in - it collects waste, collects heat and stores it for next shower. Dunno how much energy a typical refrigerant can store tho. Also great fit for Japanese-style smart baths (press a button and water of desired temperature fills and stays warm), tho they seem rare outside Japan.
    - theluketaylor 4y ago
      I think they can recover up to 60-70% of the heat in the drain water. Not bad for totally passive. The installs I have seen are on the main drain for the whole house and located right next to the hot water heater. For it to really work you need a hot water tank, but I have seen some small tanks combined with tankless.
    - shellfishgene 4y ago
      There are systems that replace the shower drain with something like a heat exchanger, the water is warmed with the drain water right away, no need to store the heat. For example https://www.oeko-energie.de/shop1/de/eco-shower-duschrinne.html https://www.oeko-energie.de/shop1/de/eco-shower-duschrinne.h... (in German, but the image is simple to understand.)
- xani_ 4y ago
  If you already have water-water heat pump I'd imagine it would be a heat exchanger away from recovering at least some
rsync 4y ago
"My new dryer is a heat pump. Uses less than half the energy my previous one did. It does take longer to dry clothes ..." I used a very modern heat pump dryer in Switzerland all summer and "... longer to dry clothes ..." is an understatement. A normal, mixed load of clothing took a full 2.5 hours to fully dry. It reminds me of CF lightbulbs: a failure to solve the real, big problems (efficient and clean generation of electricity) leads to widely distributed pain for end-users (dryers taking hours or terrible, dim, purple lighting). Far more interesting than hyper optimized electrical loads would be abundant clean energy sources. I would rather have solar panels and free electricity than have utility power and weird, complicated clothes dryers. ... and yes, my analogy is imperfect because the lighting issue was elegantly solved with LEDs. That's unlikely to be the case with clothes dryers, however ...
- post_break 4y ago
  If you need clothes dried in a hurry there is an optional heating element in some dryers that makes them on par with regular dryers.

dzhiurgis 4y ago

Hot water cylinders can have heatpumps too! Wish we found a solid way yo harvest heat from waste water. So much energy is wasted on showers - similar to EV driving at highway speeds.

throwaway4220 4y ago
https://en.m.wikipedia.org/wiki/Countercurrent_exchange https://en.m.wikipedia.org/wiki/Countercurrent_exchange A lot of mammals do this including humans. Don’t know if there’s a drop in plumbing shower solution.
bombcar 4y ago
We do it. It’s not yet economically worth it but I’ve seen installs. I can’t find it but I saw one that was designed to let a massive shower run continuously with very little heat loss - the water coming out the end of the drain was as cold as the inlet water from the main. https://en.m.wikipedia.org/wiki/Water_heat_recycling https://en.m.wikipedia.org/wiki/Water_heat_recycling
theluketaylor 4y ago
drain water heat recovery is already a thing. It's code for new builds in British Columbia, Canada. It's only expensive due to the amount of copper. The actual install has no moving parts and is completely passive. https://www.nrcan.gc.ca/energy/products/categories/water-heaters/14568 https://www.nrcan.gc.ca/energy/products/categories/water-hea...
- dzhiurgis 4y ago
  What efficiency are these? Brainstormed this a bit and feels like shower cabins (pretty popular over NE Europe) should have such system as standalone... As in - it collects waste, collects heat and stores it for next shower. Dunno how much energy a typical refrigerant can store tho. Also great fit for Japanese-style smart baths (press a button and water of desired temperature fills and stays warm), tho they seem rare outside Japan.
  - theluketaylor 4y ago
    I think they can recover up to 60-70% of the heat in the drain water. Not bad for totally passive. The installs I have seen are on the main drain for the whole house and located right next to the hot water heater. For it to really work you need a hot water tank, but I have seen some small tanks combined with tankless.
  - shellfishgene 4y ago
    There are systems that replace the shower drain with something like a heat exchanger, the water is warmed with the drain water right away, no need to store the heat. For example https://www.oeko-energie.de/shop1/de/eco-shower-duschrinne.html https://www.oeko-energie.de/shop1/de/eco-shower-duschrinne.h... (in German, but the image is simple to understand.)
xani_ 4y ago
If you already have water-water heat pump I'd imagine it would be a heat exchanger away from recovering at least some

rsync 4y ago

"My new dryer is a heat pump. Uses less than half the energy my previous one did. It does take longer to dry clothes ..." I used a very modern heat pump dryer in Switzerland all summer and "... longer to dry clothes ..." is an understatement. A normal, mixed load of clothing took a full 2.5 hours to fully dry. It reminds me of CF lightbulbs: a failure to solve the real, big problems (efficient and clean generation of electricity) leads to widely distributed pain for end-users (dryers taking hours or terrible, dim, purple lighting). Far more interesting than hyper optimized electrical loads would be abundant clean energy sources. I would rather have solar panels and free electricity than have utility power and weird, complicated clothes dryers. ... and yes, my analogy is imperfect because the lighting issue was elegantly solved with LEDs. That's unlikely to be the case with clothes dryers, however ...

post_break 4y ago
If you need clothes dried in a hurry there is an optional heating element in some dryers that makes them on par with regular dryers.