COOKING APPLIANCES

I think we can all agree cooking is as much art as it is a science. Cooking appliances are simply tools but it’s pretty hard to be artistic when given the wrong tools.

There will always be a lot of debate when discussing the merits of some specific item. Some people swear by ‘Dutch ovens’ claiming they are the best without really knowing why or how these are best.

For off-grid people the amount of energy that is used is the most important consideration. Cooking is the process of applying heat to food stuff in such a manner as to render the food edible and palatable. A conventional kitchen stove with 3 – 4 burners and an oven is not always the most efficient way to cook food. Counter top appliances are specialized tools intended to do the job in the most efficient way.

Examples of this are slow cookers or Crock Pots. These often only use 100-watt elements to slowly simmer stews and sauces over a longer period of time. This can be very effective when used in conjunction with solar panels that produce a modest amount of power over the span of the day.  The crock pot is often a double layered container with a lid that keeps the heat inside.  In other words very little heat escapes and is wasted.  The better models even have a temp sensor to cut off the power if it gets too warm.

Rice cookers are similar but use more power and are optimized to gently steam rice to perfection.  Compared to a conventional stove with a pot on top this also serves to optimize energy use because it eliminates operator error in guessing how much energy to use. In addition it eliminates the mismatch of pot and burner dimension that allows wasted heat to escape up around the sides of the pot.

The conventional stove with the spiral rings that become glowing red-hot is not particularly efficient in transferring heat into the food using the minimum amount of time and energy to get the job done.

Type of food and style of cooking plays an important part. Consider a wok and a slow cooker. The wok needs very high temperatures to lightly sear the food outer surface while leaving the insides moist and tender. If the wok is held at a much lower temperature   the results are disappointing and sometimes unpalatable. A slow cooker is the opposite. It gently warms a mixture of ingredients and allows the flavor to suffuse the entire mix over many hours. 

Several styles of ‘toaster ovens’ exist; each with its own specific advantages. At its most basic, they are just the same as a toaster laid on its side with some kind of glass door in front like an oven.  They are constructed with a single layer of metal where the outside surface gets almost as hot as the interior. This represents escaping and thus wasted heat. Better models have a double layer construction possibly even some insulation in   between and better fitting doors. There may also be a heat control knob that allows the user to control partial heat settings for less energy consumption.

Some of these ovens use a calrod heater element while others employ a quartz glass tube. Although both glow red when in use the quartz tube emits longer wavelength infra red heat that penetrates deeper. The resistive wire or calrod tends to char or brown the surface of the food like a slice of toast being browned. The quartz tube ovens are better for dishes like pies and deeper dishes because   they heat the entire portion without burning the surface layer as quickly.

Convection ovens heat foods by circulating heated air instead of direct heating by radiant means.  The manufacturers claim this will allow you to bake a cake; something not so easily done in a toaster oven.

Some  convection oven combine a rotisserie  function with the hot air flow for more even cooking  of the  surface of a bird or roast.

Several countertop grilles are now available with the George Forman grill possibly being the best known, thanks to widespread advertising and marketing in big box stores. 

Because these countertop appliances deliver exactly the right amount of heat into the food in the shortest possible time the end result is lower energy use.

These grilles have several advantages. Their design brings heat to both sides of a piece of food simultaneously. When cooking fatty meats the sloped design drains the fats away from the meat. Nutritionists regard this as a preferable method of cooking fatty meats.  This design lends itself to quick food preparation because you can take a frozen meat patty or steak place it on the grill and be done in 4 minutes or less.

The ribbed design leaves air pockets in between the browning strips that give that pleasing striped char texture.  It also makes great grilled cheese sandwiches.

The  small  one  patty size  only uses a 600 watt element  while the  large 4 patty  grill uses a 1100 watt element. The amount of heat wasted is minimal because the grill closes like a clam shell to keep the heat inside. 

Another countertop device is the roaster pan with lid.  Hamilton Beach makes a pan that can accommodate a 20 pound turkey with trimmings.  According to my   cook expert this appliance takes about half the time to cook a bird compared to a conventional kitchen stove.  One reason may well be that the lid fits snugly over the top thus keeping in all the heat.  A normal kitchen oven has a 1” diameter chimney that continuously vents hot air into the kitchen space.

The volume inside the roasting pan is more like an enclosed Dutch oven than the larger volume contained inside a regular kitchen oven.  With a temperature regulating control less energy is required to maintain the heat for cooking inside the smaller volume.

A normal kitchen oven is supplied with 240 Volt to a 3000 watt element whereas the countertop appliance is powered by a 120V fed from a 1500 watt outlet. The rating plate says the pan element is 1100 watts.

From the above it is evident all of these countertop cooking appliances can be powered from a 2500 watt inverter and a suitably sized battery bank. If charging from wind, water, or solar takes place at the same time so much the better.

This is not to suggest  off-grid cooking  can  be done electrically as if  you are still connected to  the grid but it does highlight  that some  careful use  can be made  of  a few  select electric appliances. Unlike  wood stoves or even most  gas fired appliances,  electric appliances can be set to start with a timer  on the  occasions  when everybody has to be away from home  and are not available to  cook  the meal during the  day.

Sometimes this can be a real advantage.  When everyone is away all day, loading a truck with firewood it’s nice to come home to hot chili stew and fresh baked bread. Timers can be used to sequence the bread maker and the crock pot making the stew.

FUELS FOR OFF GRID

A large part of living of grid is finding ways to power equipment and appliances.

At first blush solar looks great due to its apparent simplicity.  However if a hail storm damages a solar panel it is not usually possible to repair by hand in the field.

A wind turbine stands a better chance of being repairable in the field as does a water wheel.

Reliance on fuels and power derived from highly industrialized sources takes away from the independence sought after by people wanting to live off grid,

The recent natural disasters in Japan with earth quakes and Tsunamis illustrate this point clearly. These disasters crippled a highly industrialized nation. Even basic food growing is affected because they need refined fuels for the farm machinery, not to mention a road network to deliver food from farm to city customers.

Because of the massive advertising and general literature many people are not aware of any alternative to buying gasoline at the pump. The ubiquitous internal combustion engine can run on a variety of fuels. Spark ignition engines can run on a variety of gaseous fuel such as propane methane or natural gas which is simply another word for methane. Alcohol is yet another fuel which has been used for decades in both race cars and industrial engine. A hundred years ago naphtha was used as a fuel.

Compression ignition engines  commonly called diesels  can  run on refined diesel fuel but also on vegetable oils  both new and waste sourced and  with  some modification propane and natural gas.

During the war time years ingenious adaptations to use wood gas as fuel was widely adopted in Europe.   Wood gas is something that can be made at home. No one is suggesting these alternative are as  good as  refined diesel or gasoline but  if the fuel is something  you can  create yourself  from local  resources its worth looking into

Waste wood is one of the most common home fuels since time immemorial.  But there are many more methods to use it than simply burning it.

A quick Google search will find enough hits to fill a thick book.

Methane and natural gas are two names for the same chemical substance. The naming is primarily used to designate the source. Gas from deep drilled wells is termed natural gas but the same gas derived from decomposing organic matter is called methane. Both can contain trace contaminants that must be filtered out before use.

Methane is my favorite off-grid fuel because it develops naturally whether you want it or not. That challenge is to collect and store it for later use.

Land fill sites treat methane as a nuisance waste product originating in the garbage heaps. Enterprising land fill operators have for a few decades been collecting this gas and using it for generator fuel so the operation is energy self sufficient.

The irony being land fill sites are designed to minimize methane creation. Think what they could be achieving if they optimized the land fill site to create methane.

All farm and livestock operations generate a huge amount of methane from the animal manure. To them it is a disposal problem. Why not instead make it a resource instead of a problem   A Frenchman called Jean Paine developed a composting system that heated and lighted his farm and gave him fuel for his farm vehicles .Look here:

http://www.youtube.com/watch?v=JHRvwNJRNag

Another farmer named John Fry experimented with animal manure. Look here:

http://journeytoforever.org/biofuel_library/MethaneDigesters/MDToC.html

His book written in 1975 can be downloaded (12 chapters) because it is no longer copyright protected.

Every month I get a different collection of hits when I enter the same search string into Google, clear evidence this is a popular and very active topic.

For those who live in a conducive climate region look up Jatropha and Yellowhorn plants, these are both oil bearing trees and bushes   that can be harvested year after year. The berries are pressed to yield  a vegetable oil suitable for either cooking or direct use for diesel engines,  I have seen figures of 800 gallons per acre per year and  in favorable  regions  perhaps even greater yields. This could be a cash crop in addition to being  a home brew fuel  situation.  Conventional harvesting machinery and techniques  suffice. This is not rocket science requiring  strange new equipment, techniques or knowledge. This is just  ordinary farming  with a different crop.

I have not touched on  the more conventional  subjects of sun wind and water power  because so many other website already cater to these subjects.  My goal is to  highlight  subjects  relevant to being off grid but not covered  in detail in the mainstream literature.

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BATTERY CARE AND MAINTENANCE

Everyone already know about checking   the specific gravity of the cells and topping up the electrolyte with distilled water not tap water but there are additional things  related to good care and maintenance.

In addition some people are now using AGM or GEL batteries.   This completely changes battery and maintenance procedures.  With the batteries being sealed it is no longer possible to check specific gravity.

Several reasons justify use of these sealed, spill proof batteries.

Transportation regulations make transport of the traditional acid filled lead batteries more difficult because they are classed as hazardous material.  No such restriction exists for AGM.  This makes it possible to ship them to places carriers like UPS would not otherwise consider.

AGM batteries have less self-discharge and do not sulfate as quickly. This makes them attractive for applications where prolonged periods of inactivity are regularly encountered.   Vacation cabins may have a solar panel on the roof but in the absence of an occupant, who removes snow from the panel in winter times?  The result could mean long periods between full recharge sessions.

Sulfation is most likely to be a problem under circumstances of intermittent use and periods of sitting partially discharged. Lead sulfation is the normal result of converting sulphuric acid and lead into a current flow. 

Although every user manual clearly states to recharge a battery immediately after use how many people actually pays heed to this.

They will partially discharge a battery, and then leave it sitting because they have not discharged it fully. I have to confess I am guilty as the next person. The usual excuse being the battery will be used again real soon and we all know it can be destructive to leave a charger permanently attached and running.  The rationale being the battery goes back on the charger right after we fully discharge it.   Trouble is, that never seems to happen.

Now we have an expensive battery sitting they’re slowly deteriorating and loosing its capacity. 

Apart from constant vigilance and care there are some other things you can do.  Products called desulfators are available.  These are electronic pulsers that soften the accumulated lead sulfate so that it will revert back to sulphuric acid and lead oxide when a charge current is run through it.

As electrons are withdrawn from a battery lead sulfate forms as part of the process.  This sulfate is initially soft but begins to harden over time. A close analogy is thick mud splashed in the vehicle. When it is fresh and wet rain or a regular garden hose can easily rinse it off. As it dries and hardens   it becomes more difficult to remove.  Leave it baking in the sun for a week and you need a pressure washer to remove it.

Sometimes thick encrustations are even difficult to remove with a pressure washer requiring several tries to remove it.

Lead sulfate is similar.  In this case the electrical voltage is the pressure and the volume of water is the current.

Because  PV panels are very expensive  most  solar panel installation  are on the skimpy side when it comes to  charge current  and  weak sunlight  morning and evening also  detracts from the full charge current possible.

The conventional wisdom also contributes.  Most guidelines recommend a three-day reserve in case of cloudy days. This is a sensible approach.

Unfortunately it sometimes results in partial discharges then a couple of days of cloudy weather.   During this period of no sun the lead sulfate tends to harden, making it harder to reverse when finally some charge current once again becomes available.

The available charge current may not be strong enough to completely reverse the entire lead sulfate. This residue will remain and when further discharge occurs this old lead sulfate gets added to with new lead sulfate.   If a large charge current is not used this sulfate build up becomes permanent.  It may only be 1% but over time the accumulation of residual lead sulfate will rob your battery bank of storage capacity.

Attentive and prudent battery owners will have noted instructions in their user manual about  ‘equalization charges done at periodic intervals. The intent of such equalization charges is to flush out lead sulfate.

In essence it is an over charge and will cause the battery to bubble and loose electrolyte; you must top up the battery before starting and after doing the overcharge.

Unfortunately this process is not recommended for sealed AGM or GEL batteries.  The electronic desulfators are the only alternative.

It should also be mentioned that AGM and GEL cells required more care in charging because voltages vary compared to wet lead acid cells. They are less tolerant of over charging and suffer permanent damage if the batteries are charged to the point of out gassing.

Each type of battery has specific recommendations from the manufacturer.  Long service life is dependent on how closely you adhere to these recommendations.

The old garage type charger is no longer sufficient. It is a constant voltage taper current type, which is not suitable for optimum charging of any type battery. 

An added complication has to do with charge current as a percentage of total battery capacity.  Most battery manufacturers will recommend not charging at more than 25%of the amp hour rating. This means a 100 A-H battery should not be charged at more than 25 amps. What they seldom mention is the minimum charge rate should not be less than 10% so you now need at least 10 amps.  Charging a 100 Amp-Hour battery at 2 amps is not doing it justice nor will it reverse accumulated lead sulfate completely.

More recently lithium ion batteries have begun to be advertised as bulk storage suited to marine RV and off-grid homes use.

The technology has proven itself  in small battery sizes but  it is so new   we have not really seen  long term use  in  big  amp hour sizes to know if this is viable. How many people keep the same laptop or cell phone for ten years?

The really high cost also proves to be a detriment.  Not too many people can afford to put themselves on the ‘bleeding edge’ of technology.

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