Energy Saving Tips (EST) part 2, by Dave Lambert, Rainbow Power Company.

EST # 6: FANS & AIR CON:

Before we discuss fans and air con I might make a few comments about house design, insulation etc. If you are building a new house you should definitely seek advice from a book or from a building designer about incorporating some passive solar principles. The key one is to design the windows & eaves to let warming sun into the building in the winter but keep it out in the summer. If you own the house, you should ensure that all the doors and windows make a good seal when closed. When I insulated my ceiling I noticed a big difference. I also had a tinting film placed on my eastern and western windows. These exclude 60-70% of the heat. You should have heavy floor to ceiling curtains on all your windows and glass doors. These are surprisingly cheap at a well know curtain store especially during their many advertised sales. With these features my house stays cool until 1-2 pm on a hot (30 – 35 C) summers day and it stays warm until about 9 pm on a cold (0 – 4 C) winters night.

Having lots of windows and doors allows you to let in the cool air once the sea breeze or cooling evening temperatures eventuate. If your house is ‘boxed in’ by other houses or thick vegetation you might need a fan to either help the cool air to get in or the hot air out. Whirlybirds and exhaust fans can help get rid of the hot air in your attic.

With fans in the house, close and small is beautiful. Like using a small 5 Watt desk lamp to light your desk why not use a small 15 watt desk fan to cool you rather than using a distant 40- 60 watt ceiling or pedestal fan to do the same job. On a muggy summer night I must admit that a ceiling fan above the bed on low speed (about 25 watts) is very nice.

An exhaust fan over the stove not only gets rid of smoke/ smells but also heat which is welcome in the summer.

Turn off fans when they are not being used.

Turing off lights, TVs and computers when not being used will keep you cooler in the summer.

Most ceiling fans have a small switch (usually on top of the fan) to reverse the blade direction to help direct the warm upper air downwards in the winter.

Most people assume that air con is very expensive to run. This can be true- a small house sized 6 kW output reverse cycle a/c uses about 2 kW of electricity. However, in my well sealed and insulated house I only use it for 30- 60 minutes a day on maybe 20 times in summer and 10 times in winter. To be blunt this makes the difference between living in comfort or coping with ‘somewhat unpleasant’ days. A reverse cycle a/c is the most efficient form of electric heating- 2-3 times more efficient that a bar heater. A 20-30 minute ‘blast’ from mine heats a couple rooms for a few hours before I go to bed. Split system or reverse cycle are more efficient than a box window type. They are also quieter and have the advantage of also being a very efficient heater in winter.

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EST #7: COOKING

Using a conventional electric range and oven is generally the most inefficient way to cook. The conventional ‘ oven is designed for the days when a dozen sitting at the family table was not unusual. You can now purchase much smaller ‘counter top’ ovens & purpose designed appliances electric frypans, jugs, bread ovens, rice cookers etc) which would be much more efficient at cooking a 1-3 kg meal for a small family. Aldi periodically sells something like this for under $40:

sunbeam turbo oven

I use one to cook a 2.1 kg chook + spuds and it uses 1.28 kWh. A bread oven bakes a yummy load of bread using about 0.40 kWh. A rice cooker cooks 900 grams of wholemeal rice for 0.515 kWh or 0.31 kWh for white rice. A 2 slice toaster uses about 0.045 kWh for 2 slices of toast. An electric frypan cooks a couple steaks using 0.300kWh. An electric jug uses 0.04 kWh to boil 350 ml of water- using a pot on the stove takes 0.11 kWh. So remember, ‘small is beautiful’ and purpose made appliances are best.

When reading the above figures- remember if you are grid connected one kWh costs you about $0.30. If you are on a stand alone solar system, about 300 watts of solar panels will generate about 1 kWh / day. Many have systems designed to meet their needs in the cloudiest month of the year meaning they often have ‘power to burn’ at other times- try some solar PV powered cooking, especially if you can do it during the sunny part of the day.

Other general tips include: cover your pots and pans when cooking to keep the heat in; a pressure cooker is great; make sure your pot or pan is large enough to cover the whole element; cook on a slow medium heat; use a small amount of water to steam or cook your vegies; don’t boil 6 cups of water when you need one; a steak first brought to room temperature will cook faster and will be juicier- ask any chef! First defrost your food in the fridge (may take 24 hours)- the ‘cold’ it releases will make your fridge use less power while not using power to defrost it. For more details along these lines see:

www.originenergy.com.au/files/SMEfs_CookingKitchens.pdf

Using a gas stove is generally considered to be the cheapest & most environmentally sensitive method to cook- this is becoming more debatable as the the environmental and health issues become better known and gas prices are on the increase. The dirtier methods of generating power from coal are being phased out. Those on solar, be aware that many gas stoves & ovens use electricity as well (to light the elements; control oven temperature and to run an oven fan).

Using a microwave oven will use about half the energy that conventional cooking uses. However, some are concerned about the health effects of this type of cooking and generally speaking food doesn’t taste as good- eg mushy rather than crispy etc.

http://www.jmpee.org/JMPEE_PDFs/09-4_bl/JMPEE-Vol9-Pg341-McConnell.pdf 

If you have time on your hands at home you might want to consider a solar cooker- RPC sells two types complete with cookbooks and an oven mitt! For an awesome video of the largest solar cooking establishment in the world, have a look at this:

https://www.youtube.com/watch?v=gtdd5hftXVw

Online Convection Oven – Turbo 3000 11.5L Cooker Discounts | Convection Oven – Turbo 3000 11.5L Cook

www.dealsdirect.com.au

The Turbo 3000 convection oven roasts, broils, grills, bakes, and steams an assortment of food, whatever your taste.

EST #8- HOT WATER OPTIONS

Heating water accounts for 25- 30% of the typical household’s energy use. However, using off peak power is still pretty economical because it makes use of coal generated power at night which would otherwise be ‘wasted’. This is because it takes days to shut down a large coal fired generator. However, the government is trying to reduce this usage for the future when the use of large coal generation is slowly reduced. New houses are not allowed to have an ‘old school’ type of electric hot water system. What are the options?

Using gas if you have a town supply is a good option. This generates about 1/ 3 the greenhouse emissions of conventional hot water.

A Heat Pump (Quantum type brand) uses between 25 and 50% of the power of a conventional hot water system. They work best in warm climates and don’t need to be in the sun or on your roof. They are about 3 times more efficient than a conventional hot water system at 15 C but 5 times at 30 C ambient. They operate on the refrigeration cycle principle- they have a lot of moving parts and make some noise which can be annoying in the suburbs. In cool climates they may need electrical back-up.

A solar hot water system can produce 50 – 90% of your hot water needs depending on where you are in Oz. In the Nimbin area this is assumed to be around 80%- however, if you don’t require steaming hot water every day, it might produce more like 95% of your needs. I only boost my hot water a few days a year, however, I also tend to have plenty being a single user. The down side is that they cost around $4000 to install – my feeling is that you need to have a family water usage pattern to make them ‘cost effective’. You can determine this by looking at the cost of your ‘off peak (Controlled Load 1) on your bill.

If you already have a solar hot water system I suggest you only switch on the power when you need to- otherwise you can waste power by heating the water super hot which you may not require or which can be heated later by the sun. Off peak power is supplied at night but on the weekend – surprise surprise it comes on for periods during the day- again you could be using power to needlessly heat your water. I should say that health regulations say you should always have the power connected so the water is always hot enough to kill legionnaire bacteria- if you have a healthy household, I’ll let you make that choice.

There are two types of solar hot water system- the older type flat plate collector (basically some copper pipes painted black inside a glass box) and the newer evacuated tube type (usually made up up about 20 sealed tubes). The flat plate take up more room but when coupled to a stainless steel tank on the roof they are a simple and elegant piece of technology with no moving parts. You need a strong roof to take their weight. In frosty areas you need to get a slightly more expensive and less efficient sub type with a closed loop of ‘anti-freeze’.

The tube type take up less space; they are more efficient in cloudy weather and can handle very heavy frost. They have a tiny circulating pump which comes on occasionally and a number of sensors which may in time need servicing. The tubes can be individually and easily replaced if any get broken. (household insurance should cover you for hail damage).

There are two types of tank- stainless steel which as best in areas like Nimbin with good water. The other type is an enamel finish with a sacrificial anode that needs replacement every few years to prevent corrosion.

It is a complicated choice which one to get- I definitely suggest you shop around and ensure that the seller of the system will be responsible for its installation- that way one can’t blame the other if something goes wrong. I would also caution that installation is quite tricky and while good plumbers are expensive it is probably not a job for the home handyman.

This will probably be my last Energy Saving Tip unless I can think of something else to write about. A couple parting shots:

-small is beautiful;

-turn it off at the wall when not needed;

– when I have my morning walk I notice one shop with an old vid/ TV going in the window 24/7; another shop runs their ceiling fan all night (this warms the room- fans only cool by evaporating moisture on your skin & dissipating your body heat). You can buy 240 volt timers for $10- $20; 12 & 24 volt ones are also available. PIR or motion detector lights save a lot of power as they only come on when needed.

That’s it folks- Cheers (Thanks for all the positive feedback)

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One thought on “Energy Saving Tips (EST) part 2, by Dave Lambert, Rainbow Power Company.

  1. Pingback: Energy Saving Tips (EST) part 2, by Dave Lambert, Rainbow Power Company. : Sanctuary Demo

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