Soaring Heat In the Kitchen, Abundant Solar Outside
Temperatures reached a record 47c/116F in Sydney, Australia in January. But the second shock was the spike in cost of gas and electricity. The sun burns bright overhead while people turn on the air-conditioning in their kitchen. Despite the impressive range of affordable solar cook-tops and ovens, few people use solar ovens. What is really holding this technology back?
Solar Ovens are dirt cheap. Well, almost. They are as cheap as straw (for insulation), two panes of glass and a a sturdy box. They are popular in countries such as India because they are clean and free to run. You don’t need a chimney, fossil fuels or cow dung to fuel it. A Solar oven wastes nothing – the slow cook version does not waste a single drop of water or spice. The nutrients and flavours are sealed in.
Our first solar oven cost more in shipping than in the actual price. Seems we were ‘first wave’ solar-cookers in our shady village. (It seems were both first and last wave too). We paid about $250 18 years ago – at that price each meal cooked has cost less than 5 cents. If you are off-grid, this technology can pay back in just a few uses.
We now have a handful of different versions including the dangerous parabolic which burnt a hole in a wooden planter [photo below], a lightweight portable and the tubular baker. But I still prefer the old faithful that has survived being caught in the rain and filled up with water.
Solar ovens are durable, free to run, simple to make and easy to use and repair.
Best of all solar cooked food is flavoursome and nutritious.
Our Cultural Addiction to Piped Energy
Whilst ever we depend on a switch and convenient appliances, we are dependent on large scale innovation. If we step outside to try new technologies in the raw we get the chance to fuel our creative side.
The more powerful versions of this technology are rough, hot and glaring. But here is a great opportunity for the modern celebrity chefs and entrepreneurs to cook up a brighter future for everyone.
Here’s Mr Bean’s take on the cold – to get the ideas started.
The best energy principle for Cozy Living: When air moves, it cools down.
How Energy Works For Us:
Air transfers its energy to whatever to hits. When air hits the window, it transfers its warmth to the glass and the glass then transfers energy to outside when the outside is cooler. Energy (via Entropy) likes to go from hot to cold, from order to disorder, from a heat source to the wider universe. If want to stop sending energy to the universe, slow the airflow down by having smaller living spaces (you can use curtains to section off smaller areas in a large open-plan home).
The sun provides a lot of natural light and warmth. With double glazing, this warmth can be trapped. It is the still air between the two sets of glass panes that provides the insulating layer in double glazing. The insulation is not from the panes. So, if you want to let natural light through but don’t want the heat to escape than any two layers of material ie. recycled bubble-wrap, perspex, fabric will work. If you choose to use a plastic wrap, be aware that it can melt to the glass so put a layer of white curtain up first, then the wrap. A simple white curtain will trap the air between the windowpane and the room and continue to provide light. If you are serious about stopping heat loss at night, you can use a heavy blind or comforter and make sure the edges around the window are well covered. Have a cover over the top to stop warm air rising. A pelmet can be made out of wood, covered cardboard or an extra length of material draped over the curtain tops. Avoid Styrofoam as it kills many animals and never decays. Styrofoam rises from the dead to kill again.
Check the sun’s path for your location. The sun-less windows and walls of your home can be a cold sink where all the heat is zapped. Not much morning sun comes in on the west so there is little or no point in keeping these windows open for natural light unless they are your only morning light source. These are the windows that warrant the most insulation at night.
People generate a surprising amount of heat. Imagine if we were able to contain this heat and not let it continue to slip out into the universe. Can you modify some of your routine so you get to bed early where it is snug and warm? How can you optimise your access to natural light and warmth?
Gravity can also work for you. The beauty of heavy curtains is that they are self-closing using gravity. You don’t have to constantly ask for people to close the door. And curtains can be easily opened to release excess heat into other rooms of the house. Curtains made out of recycled woolen blankets can be fire-retardant and can be cleaned.
Insulation stops heat transfer. There are several ways to insulate the home and wood is one of the best insulators and also offers thermal stability. Wood has high R rating and great thermal stability. If the walls are not to be tampered with [possibly because they have toxic paint or asbestos in them] then you can use internal wood paneling. The thicker the wooden panels, the better the thermal mass. If you don’t own the home, you can build or salvage a lot of tall timber bookcases and fill them with books. (Be careful to attach the bookcases so they won’t fall forward).
Get the right amount of thermal mass. Thermal mass is not a substitute for insulation, it is the home’s air-energy battery. Too much mass can mean the room can take forever to heat up or cool down. Do the calculations to find the right amount of thermal mass for you climate and room sizes. Experiment with your thermal mass by adding thermal mass objects one piece at a time.
Air moves from high density to less density. Any passing breezes will suck out air in the house. It is not uncommon to see people stand and chat with their front door open. An open door can act like vacuum, sucking out any heat within. If you are lucky to have a door that is in a sunny spot – you can boost your natural energy source by installing a little greenhouse on the door – the greenhouse door will cut drafts (by creating an air-lock) AND the greenhouse will help heat your house. Your greenhouse airlock can be as light as a tent and made out of recycled plastic (like packaging for furniture) or glass, can be relocated to your next home. Alternatively, you could make the airlock out of white curtain material and a waterproof roof. The main aim of an attached greenhouse is stop airflow and let natural light through.
Simple Steps to Cut Your Heat and Money Losses
Rug up in the living room. Wear warm clothes but make sure the visitors are cozy too. You can offer your visitors some wraps and slippers. Permaculture is about building a sustainable culture. Building a culture that is cozy and fun for everyone is more likely to be sustainable. If you are having lots of visitors, it is great to share a cozy fire and if we use big theatrical style curtains to slow the air flow, the visitors can also enjoy the warm atmosphere.
Look up and look down. Many people forget that heat is also lost through the ceiling and floor. Low ceilings are easier to heat than high ceilings. If you have a high ceiling, make sure it is insulated and install a fan that can be reversed in winter to push warm air back down. Check all sky lights are well sealed and consider getting double glazing on them.
An extra floor pad with high thermal mass is useful where the sun can shine upon it. If you can’t insulate the floor, you can use lots of rugs underfoot to stop drafts.
Install a solar heating system that can go in through a window. Support manufacturers who use recycled components e.g. CanSolAir solarfurnaces. A ‘floating floor’ can be used as a low-cost low-thermal-mass large-area heater. It can contain pipes that are heated. The heating can be done outdoors by the sun. You can even use recycled pipe, a compost pile, or tank that is heated by a slow outdoor burner. A floating floor would be tricky to take with you, but something like a bench seat above it could be handy and fun. The pipes could be a simple coil of black pipe that sits outside the window and comes in through the window via a modified wooden panel with holes for the pipe inlet and outlet.
Turn your Savings into Investments
We don’t need to suffer the cold and we don’t have to suffer big bills. There are lots of options for getting cozy. The first focus would be to reducing the losses.
Once your energy losses are cut, you can evaluate how much heating you need. Invest your savings in energy from nature like capturing the warmth from the sunny windows onto thermal mass or getting solar heating piped in through a modified window pane. These tools and skills are transportable and can travel with you to your next home.
Cutting your big bills gets you the resources to build a sustainable future.