Running a kitchen on intermittent energy

Terraformer · 2024-07-17 11:35:44

Kitchens are the biggest use of domestic electricity, especially if the washing machine is located in it. Almost all of this electricity, bar the motor in a washing machine or dryer or pump in a dishwasher, is used to produce heat for boiling water or cooking food, and as we have discussed many times, storing heat is far simpler and cheaper than storing energy in a form easily converted back to electrity. So if we are to run a kitchen on intermittent electricity it is worth seeing what can make use of stored heat instead of batteries.

It can be taken as a given that hot water for washing will be from the homes hot water tank, and that refridgeration uses insulation and ice for buffering. What about near boiling water? There are countertop insulate water boilers available that could be heated during times of high electricity production. The one in the link uses 2W to maintain the temperature; a larger boiler will use more, but less per litre, and perhaps we can improve the insulation to reduce these losses further. Between cups of tea, coffee, and cooking, a household might use perhaps 4-5L of boiling water day per person, requiring ~500Wh to boil. Storing enough for a couple of days should be doable.

For cooking, obligatory Low Tech Magazine article on insulated cookpots. Most of the heat used in cooking is wasted rather than going into the food. For convenience items such as air fryers and microwaves, I think this is an acceptable cost, and would simply install storage to run them. But for stovetops, perhaps we can achieve sufficient heat from hot water stores and insulate the pots. It would also be an option to look at phase change materials to achieve consistent high temperatures. A slow cooker with an inbuilt paraffin wax heat store?

But the single biggest win, as always, is probably in hot water. Especially if the grid is unreliable. Having a big tank of near boiling water and a supply of tea, instant hot chocolate, and meals that can be made with it would make blackouts less miserable.

tahanson43206 · 2024-07-17 15:16:11

this post is reserved for an index to posts that may be added by NewMars members over time.

This interesting new topic is unlike so many of our topics, in that it is accessible to almost everyone, and almost everyone can experiment with ingredients and procedures.

I do a lot of slow cooking, and have for many years, so expect that the results achievable using the methods you are advocating might be something I could see.

For all members ... please consider trying whatever Terraformer offers by way of recipe and methods, and let us know what happens.

(th)

Terraformer · 2024-07-17 15:52:19

I now have a goal of converting a camper van once I have a drivers license and some money lol Seems to be the best way to go about a testbed for the Neo-dymaxion house. At least, one that could be affordable to me within a couple of years...

Calliban · 2024-07-17 15:53:11

Slow cookers are the easiest way of improving the energy efficiency of cooking because they are a COTS solution. I did some experimentation with low temperature cooking after we discussed it on this board awhile back. I found that whilst most meats will cook adequately at 80°C, vegetables required temperatures of around 90°C to adequately cook. I discovered that I could reduce power consumption further by covering the whole cooker with a towel, reducing heat loss. One way of cooking adequately on intermittent power would be to heat a meal to boiling in a slow cooker and then place the pot within a hay box.

I agree that having a supply of stored hot water would make long power cuts a lot more bearable. This boiler can store up to 30 litres. But nothing is said about insulation.
https://www.currys.co.uk/products/igeni … 39976.html

This is an application where it could be worth making boilers with compact aerogel insulation that can keep the water hot for at least a day without power. Some sort of sealed phase change material that melts at close to 100°C would also help to maintain temperature.

My own partial solution to the threat of powercuts is a wood burning stove in my front room. I can cook on top the stove, as it reaches temperatures of 100°C. I have succesfully cooked small meals over candles as well.

Last edited by Calliban (2024-07-17 16:08:54)

kbd512 · 2024-07-17 19:31:29

Throughout Hurrican Beryl and its nasty aftermath, we never lost our natural gas supply, nor did we lose water pressure, because all the waste water treatment plants are equipped with their own onsite diesel generators. We had hot and cold water for cooking, cleaning, and showering as a result. The natural gas supply here in Texas, and most of th rest of the country is self-powered by natural gas fueled diesel pumps.

Everything electric is now electronic, not merely "electric", and all of it is very fragile in ways that pipes with fluids flowing through them are not. The temperature of the water within a hot water pipe can vary by tens of degrees, yet the water doesn't stop flowing. If one leg of a 3-phase AC power supply is 10 degrees out of phase, you don't have a functional electric grid. If the electric load isn't perfectly matched to the electric supply, to within a millionth of a second, you no longer have a functional electric grid.

There are still plenty of ways to screw up a water line or compressed air or compressed natural gas line, but the acceptable fluctuation range is enormous compared to electricity, so a problem with the supply doesn't instantly render the enter system or large parts of it completely non-functional.

Say we had 600psi compressed air lines to supply power to spin air turbines that power dishwashers or clothes dryers. If the pressure drops to 500psi due to circumstances beyond the grid operator's immediate ability to control, you have less efficient dishwashers and dryers, yet the power supply isn't completely disabled. You can still spin their air motor, but not as fast. Electrical devices controlled by electronics don't work that way. If that supply voltage or amperage dips by 10 Volts or 10 Amps, it's highly probable that you no longer have a working electric motor.

That's why electricity should be generated onsite, and only in the amounts required to run devices that must be electrical or electronic, such as lights, computers, cell phones, and televisions.

Energy Production, Consumption, and Rejection

United States, 2017:

United States, 2022:
US%20Energy%202022.png

There is no "energy transition" underway. The Democrat's criminal syndicate wrote their donors blank cheques totaling $392B for "climate change action", whatever that was supposed to be, but apart from depressing the economy and paying off their party donors, there's no transition to anything at all, presently underway anywhere in the world, except perhaps to third world national status as reliable energy is deliberately forced out of the market through anti-humanist mandates.

We're burning more natural gas in 2022 than we did in 2017, but that's about it. As Peter Zeihan pointed out, we figured out how to get 5 units of energy output for every 1 unit of natural gas input, relative to burning coal. That's the only "transition" that's made any difference to the climate or to energy consumption rates.

China, 2017:

France, 2017:

India, 2017:

Russia, 2017:

United Kingdom, 2017:

France actually has the "green(est) energy", with the lowest total quantity of waste generated by far, because they use "nuclear energy" and do their own fuel reprocessing in conjunction with the United Kingdom.

Heat and pressure do nearly all of the heavy lifting, regardless of where that heat and pressure comes from (coal, natural gas, nuclear fission). For us to transition to a primarily solar powered world in any reasonable amount of time, we will require over-glorified "water boilers" directly powered by sunlight and machines with no moving parts. Any long-term viable "natural energy" grid, not "green energy" because there is no such thing, we need lots of direct heating and pressure, supercritical CO2 turbines to efficiently extract thermal power, trompes sunk into the oceans to compress air for motor vehicles, residential, and construction uses, and absolutely enormous energy storage facilities the likes of which have never been built anywhere. Electricity is not a panacea, and thus far it's proven to be more of an impediment than a facilitator of transition, because every aspect of using electricity is so wildly inefficient, relative to under-utilized competing alternatives.

Calliban · 2024-07-18 03:04:31

On the topic of compressed air...

The Amish have done some work developing kitchen air tools. Most air tools that I have seen work at pressure between 70-150psi. In most cases, they still work at lower pressure. They just don't give the same power or torque. At 150psi(a), 1m3 of compressed air will generate 1.2MJ (0.33kWh) if expanded adiabatically and about twice as much if expanded isothermally. Adiabatic expansion allows use of simple expanders without the complexity of multistage expanders and reheat heat exchangers. Most air tools are adiabatic and are usually cheaper, lighter and more powerful than electric tools.

A 3m^3 receiver tank would contain enough compressed air for 1kWh of energy provided to adiabatic tools. The receiver tank will be expensive to buy. But once it has been purchased, it should last forever if kept in dry conditions and given the occasional coat of paint. The efficiency of compressing air into the tank should be greater than calculations suggest, because residual air cools down in the tank as pressure drops. One way of improving the efficiency of compression and expansion would be to capture the cold resulting from expansion in a phase change material like brine or methanol solution. Air input to the compressor can then the drawn through this phase change material, precooling it. This would have the beneficial effect of drying the air as well and preventing mousture from entering the receiver tank.

In the kitchen, a compressed air powered fridge or freezer, could actually generate electric power for the house whilst using the cold exhaust air to cool the fridge or freezer. Cold exhaust air from air tools will contribute to air conditioning in hot climates. In some cases, it may be possible to capture the cold air from such tools and route it into a pantry, which can store perishable foods beneath 10°C.
**************

PS1. A 2000 litre, 11.5bar(g) (167psi) air receiver tank cost about £4000 after tax. That is about $5000. So this looks like an affordable solution.
https://airlinkcompressors.com/products … eq=uniform

PS2. This Amish chap has integrated a wind powered compressor into his facility. He has 3 receiver tanks that look to be about 500 gallons each. He uses compressed air to run internal equipment and ceiling fans.
https://m.youtube.com/watch?v=Oc0b4aBOyBw

Last edited by Calliban (2024-07-18 07:05:43)

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#1 2024-07-17 11:35:44

Running a kitchen on intermittent energy

#2 2024-07-17 15:16:11

Re: Running a kitchen on intermittent energy

#3 2024-07-17 15:52:19

Re: Running a kitchen on intermittent energy

#4 2024-07-17 15:53:11

Re: Running a kitchen on intermittent energy

#5 2024-07-17 19:31:29

Re: Running a kitchen on intermittent energy

#6 2024-07-18 03:04:31

Re: Running a kitchen on intermittent energy

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