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Something I've wondered about recently - often times in a kitchen you want hot water and a cold box for food - and lately there are heat pump water heaters avai
by csours 2y ago
Something I've wondered about recently - often times in a kitchen you want hot water and a cold box for food - and lately there are heat pump water heaters available on the market. Is there a fridge/water heater combo yet?
- Avamander 2y agoThere's not enough heat in the fridge to heat up any significant amount of water. I would however like to see that waste heat being used for something like dishwashers or just being vented out (instead of into the room that might have to be actively cooled).
- nimish 2y agoAny heat used is better than no heat used. Water heaters that are also AC units do exist (a heat pump is an ac run backwards)
- bongodongobob 2y agoNo it's not. Claiming heat from a fridge would be like grabbing a cup of water for a minute a few times a day. The extra shit that needs to be manufactured and transported is surely not worth the effort at all.
- cameldrv 2y agoI wouldn’t be surprised if someone starts making these. The heat that comes off a typical refrigerator is enough to heat about 1/3 of a typical house’s hot water usage.
- bongodongobob 2y agoWhat?? Not even close.
- orra 2y agoTo put numbers on this, you can buy a C rated fridge freezer in the UK which uses 176 kWh of energy per annum. That's an average power consumption of 20W. But electric heaters are say 1200W or 2000W.
- Avamander 2y agoThat includes the lights and all the rest. That gives you like 3m³ (790 gallons) of 60°C (140°F) water. Which is really not a lot.
- Nevermark 2y agoMini-split HVAC systems create both heated and cooled air, and send them to just the rooms they are needed, while also redistributing existing disparities of hot and cold. The latter being the most efficient HVAC mode of all. I could imagine at some point, all our heated and cooled air, water, and ice could be one system. For fast temperature demands, such as hot water or ice, perhaps reservoirs of chemically stored heat and cold could be built up at useful locations, for very high speed release when needed. Completely dispense with storing hot or cold air/water, except for fridges. But provide the cool air for them, as a byproduct of being one system, avoiding the local inefficiency of both cooling air in small quantities and generating heat at the same location. It would make it cheaper to have more fridges and ice makers around a houses, if you just had to plug them into power and an HVAC controlled "inlet/outlet".
- nimish 2y agoCorrect! This is how some advanced systems already work in multifamily, where one room's excess heat is routed to another rooms lack of heat -- "Variable Refrigerant Flow" or VRF
- nimish 2y ago> Claiming heat from a fridge would be like grabbing a cup of water for a minute a few times a day. Did you know that people do this? The brits love making a cuppa tea. It's free energy and the heat pump in the fridge is already doing the work.
- mrshadowgoose 2y agoNope. If the cost to "reuse" the heat exceeds that of the status quo, it simply doesn't make sense.
- cameldrv 2y agoA lot of people have these in their houses already. Go to Home Depot some time and you’ll see lots of heat pump water heaters.
- mrshadowgoose 2y agoSorry, didn't see any "kitchen fridge/hot water tank combo units" on their website. Care to provide a link? Or perhaps you may have missed a nuance in the comments above yours? Nobody is claiming that heat pumps don't work, they certainly require a source of heat to pump though, and the air in a kitchen fridge ain't that.
- cameldrv 2y agoYour comment in reply to: "Water heaters that are also AC units do exist" https://www.homedepot.com/b/Plumbing-Water-Heaters-Tank-Water-Heaters-Heat-Pump-Water-Heaters/N-5yc1vZckra https://www.homedepot.com/b/Plumbing-Water-Heaters-Tank-Wate...
- mrshadowgoose 2y agoJust a heads up, your reading comprehension kinda sucks.
- Smoosh 2y agoMany modern homes have a perforated panel in the ceiling behind the refrigerator to allow the heated air to escape the room.
- ghostly_s 2y agoCitation needed.
- beejiu 2y agoWaste water heat recovery, which heat exchanges with inlet water, would probably be more effective than heat exchanging with a fridge. Realistically both options are too costly for the limited benefit.
- fredophile 2y agoI looked into waste water heat recovery a few months back and it is a thing you can buy. You buy a special section of pipe that has a straight pipe with another pipe coiled around it. Some of the heat from the waste water gets transferred to the water coming in as they flow past each other in the pipes. They cost a few hundred bucks. I have no idea if the long term savings justify the cost (if you're looking purely at money for benefits).
- sebazzz 2y agoThese exist for showers, shower heat exchangers let the drained hot water exchange heat with the cold water tube to the shower.
- thijson 2y agoEven for a furnace or boiler, condensing the steam in the exhaust only makes it around 10% more efficient.
- russdill 2y agoIf you look at the temperature deltas, we really don't do much to cool our food. You can verify this by comparing the power requirements of a fridge with just about anything that heats water or food. You could save some power, but not very much.
- deleted 2y ago[deleted]