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 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 in summer if you have air conditioning.
In any case, an exterior heat exchanger and heat pump that can handle a wide exterior temperature is much more heavy duty. This could all end up being less efficient, in practice. House-scale heat pumps can efficiently move heat even from a freezing cold outside into a warm interior. Just as fridges can efficiently move heat from their cold interiors to a warm room.
Even if we consider incandescent light bulbs, which waste most of the energy they use as "heat", that heat is actually being transferred primarily through radiation, so it can escape through windows more easily than the heat that a furnace transfers to your indoor air.
Still, not much is going to hit a window on average. So maybe 90% efficient.
Surely properly installed gas boilers always did that even without balanced flues too.
There is something very very wrong with your equipment (or you're measuring something else not having anything to do with the heating equipment - more likely). A high efficiency furnace has a sealed combustion chamber, the entire thing runs in a circuit vented to the outside - combustion air comes from the outside and it is vented to the outside. If it is not airtight sealed from the indoors, it is broken. Even a mid-efficiency furnace with a non-sealed system will vent 100% of the flue gas outside.
> Natural gas combustion is at best _mostly_ exhausted.
Bullshit for any modern equipment (ie installed in the last 50 years).
But yes, the GP is full of shit. Maybe they have some other non-induced vented gas burning appliance (ie a hot water heater or gas hob), or their measurement equipment is faulty.
Or you live insulated from shitty alliances and low income life.
A friend's husband was killed by a faulty boiler, carbon monoxide poisoning. In 2015 I lived in a house where boiler ignition didn't work and you had to reach inside with a lighter. That unit was definately not sealed.
UK only required consenser boilers since 2005, the ones before that used to air from inside your house.
Whether most boilers are prehistoric, or it's just years of neglect, I don't know.
"It does cost more to run an appliance than to heat with gas."
That's highly dependent on the appliances involved and the price you pay for each fuel. For me, a heat pump is much cheaper to run. You really need to calculate it for each individual situation.
If I'm running my computer to use it & it keeps me warm, there is no way turning on a natural gas heater is going to reduce my costs.
If you have a thermostat in your home, any appliances you use will reduce your heating usage because the thermostat will automatically decrease how much the furnace runs. So, yeah, it’s not wasteful to vent your computer exhaust outside in the winter, but no one’s doing that. On the other hand, it’s not worth it to run appliances you wouldn’t otherwise run unless you have an electric furnace, in which case it doesn’t matter.
Uh, come again? If I am using my computer anyway - why would I exhaust the waste heat outside if I have to heat the indoors anyway? That is wasteful.
Your fridge has the potential to go even higher than 100%, as it's a heat pump. But for more than a temporary effect you'd have to keep replacing the stuff inside it with stuff warmed up to outside temperate, which would have to be between fridge temperature and room temperature. Perhaps slightly impractical.
I really enjoyed reading The Homemade Heatpump Manifesto on Ecorenovator. https://ecorenovator.org/forum/showthread.php?t=484
Voila: everyone has heat pump heating! (And dead compressors).
The dumb thing is having the compressor itself indoors in summer. Should be outside.
Yes, more efficient than a resistance heater. Possibly more cost efficient than gas.
Wastes a lot of water (if you don’t have a well).
A fridge is just a heat pump.
Today fridges are more or less plug and play. Most kitchens don’t have a hole in the wall going outside where the fridge would go. Some kitchens aren’t even on walls facing the exterior (which I dislike, but they exist)
I often see my HVAC cooling when the set-point temperature is actually _higher_ than the outside temperature. Logically, the house is a heat generator, it makes sense physically. The roof is black, etc.
It would offer a good number of benefits if the system could outright open a duct to the outdoor air, and suck it in whenever the local outside temperature is within the range requested by the user. People who are into optimizing energy use (they exist) can go even further and pre-cool their house during the night in summer.
For this to work, all you need a pusher fan, no refrigeration at all. There might be some pressurization problems, like, you may need a duct both for the intake and outlet. Also might require another filter... but air quality would improve significantly.
This is a really "dumb" idea, but it's perfectly in-line with all the new ideas being thrown out there. The new ideas just tend to throw in an additional heat storage mechanism, like a water tank (in the article). You can get a lot more efficiency gains by saving the night's cold in a tank and using it through the day. But on a more basic level, you can pump straight into the house when the conditions are right.
My thought is I should keep them closed due to extra load on the AC to dehumidify the outside air. Or open windows and turn AC to fan-only mode to prevent stagnant air in rooms without windows.
Unfortunately I have only seen commercial humidification units that boil water into steam with the use of natural gas. Without exception, everything for sale for home use uses electricity (you'll need 230V minimum, single phase will do just fine) to boil the water, which is costly (though this year natural gas prices have risen or even doubled, but even in states with cheap electricity it's probably still cheaper to use natural gas).
That said, it still may be more efficient to open your windows, depending on the humidity.
The idea of doing the same in my home has been taunting me for years now. Ideally you'd have two such louvres, one with a push fan in the upper floor and the other with a pull fan in the lower floor to simultaneously eject unwanted heat, bring in fresh air, and boost whole-house circulation. They'd be set up to interface with the thermostat/hvac and would operate when the outdoor temperature at intake is lower than the temperature at exhaust and both are above the set point on the ac.
The biggest problem is really one of convenience. You'd need a filter on the intake and a rather large and powerful fan to overcome that static pressure - ergo, a noisy one. And you'd probably have to fully dismantle the system in the winter to prevent the cold from getting in (the Midwest is cursed with both hot and humid summers and cold and dry winters). It just end up being the kind of thing where the devil really is in the details and you either do it right and it's a huge undertaking or you do it fast and sloppy and its drawbacks won't be worth it.
But I agree, nothing is more infuriating than seeing the AC on and the outdoor air temperature being lower than that of the home. And opening windows just doesn't make a difference since in most 20th century homes there's just poor airflow and no circulation.
https://www.thespruce.com/whole-house-fan-vs-attic-fan-diffe...
Crack open a window downstairs before switching it on.
When it’s colder outside, liquid will evaporate on the bottom and condense at the top through gravity. Once it’s warmer outside, the whole process just stops.
No valves, no pumps, no analog or digital controls. Ok, maybe a fan.
I actually want a fridge/freezer at the cabin that works like this in fall/winter/spring. I know it’s technically moving heat from inside to outside, but I’ve got more wood than electricity to work with.
I see https://www.qats.com/cms/wp-content/uploads/2015/03/Qpedia_A...
How might this be applied to a residential setting?
Won't cooler temps outside make the AC work more efficiently and get to the desired temp more quickly?
Most of these systems have a damper that the system can use to choose how much fresh air is used or how much return air is recirculated so it’s not difficult to use that to just put fresh air in directly with no cooling or heating. Even systems with heat or energy recovery will often have a bypass damper.
You need the humidity to be in the right range as well as the temperature, but it can save a lot of energy!
1) Long refrigerant pipes. This is unacceptable because it increases the amount of refrigerant in the systems (refereed to as the charge of the refrigerant). Refrigerants are powerful greenhouse gases so it is important to design low charge systems.
2) Another process fluid (e.g. water or glycol). This adds expense (more pumps and heat exchangers). You'd increase the cost of all these systems by a lot.
Also, both 1 and 2 involve running a new set of single use pipes around your house.
3) Make a "single appliance" household. A design like this has been tried - single AC/heat pump hooked to fridge, freezer, oven, dishwasher, washer/dryer, and water heater. The problem is that you really have do design the house around this and it is quite limiting from an architectural perspective.
Combined AC/heat pump and water heater is a thing though.
Air-sourced exchanger individual appliances are just so much simpler for the consumer.
Not dissing ground-source heat pumps. Those are fine, since they are typically a plumb-once-and-done. You just generally don't want separate appliances which quick-connect.
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.
For something the size of a home fridge the costs would be immense compared to the energy savings. You're far far better off spending that money on more efficient heat pumps and more/better insulation.
The federal limit for the amount of power a fridge can pull is 527 kWh/year, which at my rates (admittedly on the low end these days) is ~$70/year. There are very commonly available fridges that are < 300 kWh/year, which would be ~< $40/year. So before even taking into account the efficiencies you implicitly make back when you're heating your house anyway, that's your per-attached-appliance limit for input cost on building out, maintaining and running that system.
Though, I admit that the idea of a completely silent fridge & A/C is alluring. Here's to hoping we make some breakthroughs on sold-state heat pumps.
It was never pursued further for reasons I discussed in another comment on this thread.
They move the heat from inside the fridge to outside. That heats up your home. This reduces your need to heat your home, temporarily.
Generally, every device in your home that uses electricity is creating roughly the same amount of heat as an electric heater would have using the same amount of electricity. Even fridges and freezers, so long as nothing is being vented outside.
Keeping a big reservoir warm for the sake of keeping it warm only becomes efficient with regular usage.
From a cost perspective, the slight efficiency increase of tankless never pays back over the cost of the unit, and unfortunately, usually the more frequent repairs. The big benefit is the 'unlimited' hot water.
However unless the house was built, and / or the pool installed in a coincidentally fortunate configuration where the AC compressor and the pool filter pump are within a meter or two of each other, these devices cannot be used effectively due to impractical tolerances and insulation needed to mitigate losses from contact with the highly variable outdoor environment.
that makes no sense. effective insulation is no problem at all. In large parts of europe they even have centralized water heating and run insulated hotwater pipes to houses across kilometers without huge losses, hell, for this kind of setup it would even be possible to just run refridgerant, which typically specs at ~15m for minisplits as maximum(with very minor losses) distance
Not really, efficienty aside the heat it puts out the back is coming from inside the fridge... Which is coming from the room housing the fridge. So over the course of a day it should be neutral.
Installing ducts, etc. might take more energy than is consumed over the product life-cycle.
It would add other limitations, such as only being able to put fridges next to exterior wall.
Or most likely it'll add additional installation cost. Money perhaps better spent insulating your house better.
You'd have fewer compatible vendors to choose from. Less competition.
Flexibility is probably way more important than micro optimizations.
It can be implemented as a single line of force water flow with 20-25 Celsius. It is viable as both a heat source and a heat sink at the same time.
This thing can be connected to both your coolers and heaters, and thus transfere heat from one to another. Maybe you could even get you desktop computer into the loop.
Usually it implemented on a lager scale, but i don't see why this would work scaled down.
It should net out to no less than the same energy though, right? That refrigerator needs energy to move the heat out of the fridge and into the home. If that process takes more energy than just letting the house HVAC deal with it, wouldn’t the energy bill be higher?