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A side not I always wondered why don't we have refrigerator models that are "split system" as we have with ACs. As it stands now it's a heat pump that pumps th

by seer 3y ago

A side not I always wondered why don't we have refrigerator models that are "split system" as we have with ACs. As it stands now it's a heat pump that pumps the heat from your refrigerator into your home. Wouldn't it be possible to create way more energy efficient model that has an outside body? Or even better connects to the AC body you already have outside? Like in the summer it would "help" the AC by being another AC itself, and in the winter it would effectively be "free" as it got its cold from the outside. I'm sure there's a reason nobody has attempted this (complexity / price) but was just wondering what the data point on something like this would be? Presumably with modern buildings this could be reduced accommodated, especially with geothermal AC being on the rise right now, would be cool to have all your heat pump systems connected to a single loop, sharing efficiency.

rtkwe 3y ago
Most residential units match one outside compressor to a single interior evaporator because to use one exterior unit for both you'd need way more complex valves to control which unit is receiving cooling. Even if your matching one to one you have the added cost of running all the lines associated with that including having a trades person coming out to install and charge the extra piping between the two units and installing the exterior unit that will need power. It's just massively simpler to have a complete unit you can drop down and optionally connect to water.
not_the_fda 3y ago
Because you have to worry about cycle times. Central AC is sized to cool the entire house and is only used when its hot outside. Tying a fridge to the central AC would give frequent and very short cycle times because it doesn't require the removal of as many BTUs. The AC system's life expectancy would then be shortened.
ajot 3y ago
> Wouldn't it be possible to create way more energy efficient model that has an outside body? Lots of shops (think mostly of butchers, charcuterie or take-away restaurants) here in Argentina do this, I think mostly to avoid all that heat and noise being trapped in the premises.
LorenPechtel 3y ago
While I really like the idea of a split system approach you run into some big installation issues. Namely, the refrigerant is a restricted product that can only be handled by licensed professionals. Thus, what I would like to see is a system where the refrigerator has two air pipes to the outside and a concept of heating/cooling load. It would have an ambient temperature thermostat that would say to reject heat indoors if it's below X degrees in the room, otherwise reject it to the outdoors. It would also have the concept of using outdoor air in lieu of it's compressor if it was cold enough. (And I would like to see an integrated HVAC temperature control, also--you set the minimum, ideal and maximum temperatures. If ambient air can be used in lieu of power it does so--and stops at the ideal temperature rather than the limit temperature. Instead of heat/cool/off settings you have on/vacation/off, in vacation mode it only enforces the minimum and maximum and ignores the ideal and it has different settings for minimum and maximum. And, yes, I want a maximum when on vacation--I don't want to bake the insides at the 110F that could easily happen in the summer here.)
- hoosieree 3y ago
  I wonder if it would be worthwhile to water-cool the refrigerator's condenser coils, and use the heated water as input for a dishwasher or kitchen sink.
  - hoosieree 3y ago
    Expired patent: https://patents.google.com/patent/US5220807A/en https://patents.google.com/patent/US5220807A/en
kjkjadksj 3y ago
This is why its more efficient to have your fridge in your garage versus your kitchen. You aren't having ac fight your fridge generating heat. You aren't having your fridge fight your stove baking out the room.
tzs 3y ago
Or if not outside, I wonder if you could dump the heat someplace inside that is better than just dumping it into the inside air? Such as dumping it into the hot water heater.
fomine3 3y ago
Modern home refrigerators are efficient enough thanks to insulation materials and efficient heat pump. Adding external unit just for 500kWh/y to 300kWh/y is not what we want.

by seer 3y ago

rtkwe 3y ago

Most residential units match one outside compressor to a single interior evaporator because to use one exterior unit for both you'd need way more complex valves to control which unit is receiving cooling. Even if your matching one to one you have the added cost of running all the lines associated with that including having a trades person coming out to install and charge the extra piping between the two units and installing the exterior unit that will need power. It's just massively simpler to have a complete unit you can drop down and optionally connect to water.

not_the_fda 3y ago

Because you have to worry about cycle times. Central AC is sized to cool the entire house and is only used when its hot outside. Tying a fridge to the central AC would give frequent and very short cycle times because it doesn't require the removal of as many BTUs. The AC system's life expectancy would then be shortened.

ajot 3y ago

> Wouldn't it be possible to create way more energy efficient model that has an outside body? Lots of shops (think mostly of butchers, charcuterie or take-away restaurants) here in Argentina do this, I think mostly to avoid all that heat and noise being trapped in the premises.

LorenPechtel 3y ago

While I really like the idea of a split system approach you run into some big installation issues. Namely, the refrigerant is a restricted product that can only be handled by licensed professionals. Thus, what I would like to see is a system where the refrigerator has two air pipes to the outside and a concept of heating/cooling load. It would have an ambient temperature thermostat that would say to reject heat indoors if it's below X degrees in the room, otherwise reject it to the outdoors. It would also have the concept of using outdoor air in lieu of it's compressor if it was cold enough. (And I would like to see an integrated HVAC temperature control, also--you set the minimum, ideal and maximum temperatures. If ambient air can be used in lieu of power it does so--and stops at the ideal temperature rather than the limit temperature. Instead of heat/cool/off settings you have on/vacation/off, in vacation mode it only enforces the minimum and maximum and ignores the ideal and it has different settings for minimum and maximum. And, yes, I want a maximum when on vacation--I don't want to bake the insides at the 110F that could easily happen in the summer here.)

hoosieree 3y ago
I wonder if it would be worthwhile to water-cool the refrigerator's condenser coils, and use the heated water as input for a dishwasher or kitchen sink.
- hoosieree 3y ago
  Expired patent: https://patents.google.com/patent/US5220807A/en https://patents.google.com/patent/US5220807A/en

kjkjadksj 3y ago

This is why its more efficient to have your fridge in your garage versus your kitchen. You aren't having ac fight your fridge generating heat. You aren't having your fridge fight your stove baking out the room.

tzs 3y ago

Or if not outside, I wonder if you could dump the heat someplace inside that is better than just dumping it into the inside air? Such as dumping it into the hot water heater.

fomine3 3y ago

Modern home refrigerators are efficient enough thanks to insulation materials and efficient heat pump. Adding external unit just for 500kWh/y to 300kWh/y is not what we want.