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Jodie

(1)

That's a pretty skilful article, and wonderful art from the archives. I cant help but surmise that modern heating of space permits far greater levels of comfort, health and creativity for us in this age. Central heating is probably overused by many, and radiant heat can be part of a more sustainable solution, particularly for heating smaller spaces. I think the answer lies in good archeitecture and insulation and more sensitive thermostat and digital controls for space heating.

Gerfried

(2)

In this respect I have filed two patents (which will not be granted). One for controlling infrared lamps integrated in the ceiling bound illumination, according to the position of the persons (and the temperature). The second invention relates to the integration of an heating mat into a tubular background illumination. Furthermore the tube features a fan for destroying the temperature gradients in the room. The information will be public domain soon it is published by the patent office and the re-registration is also refused. Here are the Links to the patent office:
http://see-ip.patentamt.at/NPatentSuche/Details/471b70d8-2ffc-47d1-a3d8-f1b65e417cbb
http://see-ip.patentamt.at/NPatentSuche/Details/483db702-798f-4f80-9e74-c5a94bb15750
http://see-ip.patentamt.at/NPatentSuche/Details/282f1662-6e66-4b0f-b634-810df7aa364f

The Bare Necessities

(3)

Thank you so much for this article, and the illustrations are excellent. In winter in the US I get so frustrated by the way public transportation is heated: buses and subway cars are filled with heated air which is much too hot, and gives you a headache almost immediately (the opposite of thermal comfort, really). Moreover, it is now forbidden to open up the bus windows (they have been nailed shut), so one is forced to sit in silence, wearing full winter gear, breathing the hot hot air, and wishing for a world with less convection.

Leo Comerford

(4)

The MIT Local Warming project (Economist article) seems to have the best approach to spot heating based on stationary equipment. It apparently overcomes the radiant assymetry problem by using two or more spot lights to focus the user from different directions simultaneously. (Gerfried's first idea seems to be much the same.)

Failing that, there are the electrical heated jackets which are becoming increasingly popular: spot heating taken towards its logical conclusion. But it can probably be taken even further. The AVAcore CoreControl glove can apparently adjust the body's core temperature more quickly and (I assume) more efficiently than other means of heating or cooling. Something similar that didn't block the hand (maybe a sleeve for the forearm?) might be suitable for continuous use.

Matthias

(5)

Nice article, btw the romans has some smart heatings systems too.

What is not discussed here is vaporization and condensation. If the temperature is lower than the dew point water will condensate. This will lead to mould and other unpleasant occurrences which can seriously can harm health and also destroys the building structure. So all surface temperatures as well as air temperatures have to be higher than the dew point. Of course it is possible to dry the air and lower the dew point but dry air is also not very healthy.
So generally the end heating the air is the mist economical and ecological way of heating.

Don't forget that every car or truck will produce a lot of heat. 60%-80% of the energy content of the fuel is converted into heat energy which is wasted and leaves the vehicles exhaust.
so we could use a engine in our house using the exhaust heat to heat our home and drives a generator which provides us electricity for the house and car. Those systems are available for oil and natural gas. Powerplants fired by biomass or coal can provide heat for whole cities.

Russell

(6)

I've been reading up en rocket mass heaters. There seems to be many people improving them at the moment. There is a Dutch guy whose name escapes me at the moment but he's quite easy to track down on google, and an American couple called Ernie and Erica Wise who have a more diy approach.

Another great article, thank you.

Trina Masepohl

(7)

What a wonderful article! I'm a former Mechanical Engineer (first part of this article was a real flashback to Heat Transfer) and am now an Interior Designer. The connections noted in your article between interior design/furnishings and thermal comfort is not lost on me! Can't wait to read the next installment...

Matt Smith

(8)

- Smaller rooms
- Lower ceilings
- More human (and canine) bodies closer together in those rooms, conveying heat to one another
- Sometimes better insulation
- Sometimes passive solar heating

Mark Blossom

(9)

Alex Chernov, "Stovemaster", builds and will custom design advanced double bell masonry stoves. These systems have probably the best fuel-to-heat ratios and the least pollution of any wood burners. We are getting ready to build one of his designs with the firebox opening out into the entry way, rather than into the main living space, and integrated water heat exchangers for radiant heat in the concrete floor slab.

Etienne Bayenet

(10)

Once again, a very good article. I just wanted to bring more input regarding the fifth comment about the water condensation problem. If you have enough fresh air and no specific humidity source, condensation is not a problem but dry air is. The best way to solve this humidity problem is to insure that the windows are less insulated than the walls and the ceiling, so water will condensate on the windows.

At home, I dry my clothes in the sleeping rooms in order to get more humidity.
http://u.jimdo.com/www51/o/sd1cb7867a4db87c5/img/i2c5738e84982a5ff/1399835497/std/image.jpg

I wrote some times ago in french a long article about energy opimisation for a traditional convection heated building http://bayenet.jimdo.com/energie-et-b%C3%A2timent/
This new article is a good description of the "next step" in optimisation.

Etienne Bayenet

(11)

I also wanted to do a comment about wood heating because not only the tile stove has been improved.
The main problem of wood heating is that stoves are usualy too powerfull compared to the area that has to be heated, so people use them in a low power mode, which means a bad combustion of the wood and gases. If you are able to use your stove at maximum power all the time, you get a maximum of infra-red heating and a better efficiency. Of course, you will not get the efficiency of an improved tile stove.

Old stoves used to take too much warm air into the chimney, but if you have a new one, the fire will insure the needed air renewal for 3 to 5 people - you need around 20 cubic meter of air per hour for each inhabitant. Wood is very much renewable, and is the energy that has the most human work per kwh. Electricity is very efficient, but not its production, so the heat lost in the chimney must be similar to the heat lost for electricity production.

Heating with wood is a work, you have to clean the stove, bring wood regularly... so if you heat with wood, you will only heat when needed. This also bring efficiency.
Regarding wood pellets, I hope that its use will bring a better management of the forests in the north (Canada, Scandinavia...) and will reduce forest fire during the summer.

I believe that all type of energy should be considered. There is no good or bad energy, there are only good and bad ways to use it.

Kris De Decker

(12)

@ Matthias (#5)

Condensation and mould were not a problem in old buildings because the construction materials were vapour-permeable. Historic buildings were "breathing", modern buildings are not.

A Hamilton

(13)

We use 6.4 kW of Redwell infrared heating panels to heat our 4 bedroom house in Scotland. They are controlled by a Honeywell Evohome controller which allows 24 hour, 7 day a week control over 8 zones.

We heat water overnight in a 210L tank using an immersion heater. At some point we'll switch to an electricity tarrif that has an overnight off-peak rate - probably when we have to charge our electric car at home more often (we use workplace and public charging which is free at the moment). We're about to replace our gas hob with an induction hob.

Our fuel costs are about the same as our previous gas fired boiler system which packed in 2 years ago. Scotland has a lot of low carbon electricity generation (wind, hydro, nuclear), so our heating system has probably significantly reduced our CO2 emissions. As UK natural gas production peaked 15 years ago and imports now come from far afield, I thought it best to go electric from an energy security point of view.

Your reference to the Historic Scotland document is very interesting. I've read some of Sue Roaf's work before and heard her speak. Her work is always interesting. We heat our hallway to 16 degrees C during the day, and bedrooms and kitchen a degree or two warmer. The living room is more cosy at 20 degrees in the evening. We may experiment with heat pooling to see if we can run the living room at a lower background temperature.

One thing that our system is not good at is bringing a room from a low temperature up to comfortable temperature in a short period of time. I suspect you'ld need more kW capacity to be able to do that. Otherwise, the heating system is absolutely fantastic!

hat_eater

(14)

Great article! I have a minor/major nit to pick - sun does heat air directly, albeit only very slightly (as most of the light passes through it). If all the energy that hasn't been captured by the earth was radiated back into space, Earth would be a cold place.

Infraheat

(15)

@hat_eater

Not all of the energy that is absorbed by the surface of the earth is radiated back into space, the surface of the earth heats the air some energy is reflected from the surface of the earth however this energy is not all lost due to the greenhouse effect.

Here is a great infographic which explains what I mean.

https://www.pinterest.com/pin/568931365402591415/

John Parker

(16)

After having read this article, I thought that some of your readers may be interested in our warm clothing experiments:

With my wife, I live in a big house in Burgundy, France, which, when it was built in the 15th century, would have had all nine fireplaces burning around 15-25 cubic meters of wood per fireplace each winter (10-15 cubic meters with modern log burners), in an attempt to maintain a room temperature in the high teens centigrade. That adds up to well over 200 cubic meters of wood for the whole house, each and every winter. The forests around here stretch for miles, but the one thing you notice about them, is that there appear to be very few trees over around 30 years old. In fact, the closer you look, the more you begin to realize that wood is just another intensively farmed crop drawn from soil which has undoubtedly been impoverished over a long period of time.

For the first few years of living in this house, the full extent of its winter energy hunger was masked by a modern, gas fired central heating system, but we eventually came to understand just how extravagant it was to heat the entire house throughout the long, cold continental winters, to close to 20 degrees Celsius, just for two occupants.

My wife and I began experimenting with clothes for heating about five or six winters ago. The initial goal was to see if we could find clothing which would keep us warm, comfortable and happy even without any kind of additional heating source.

We started the experiment in the first winter with modern clothing solutions: high tech thermal layers, specialist outdoor gear and the like, but found that the problem with most of them was the extremely large surface area associated with modern fashions. The style of modern clothing more or less mirrors the surface area of the skin - the surface area of trousers mirror the surface area of the skin on legs and so on. Some of these technical fabrics worked well for relatively short periods of time, but most simply failed to keep in enough heat when days and weeks went by with temperatures close to or below freezing. To retain anywhere near enough heat, we had to resort to wearing clothing designed for outdoor extremes. It was uncomfortable to wear indoors, made us feel stupid and miserable and so we abandoned the experiment in the first winter and switched the heating back on.

The exterior and lower layers of the house are medieval but the interior was remodeled in the 18th century, so the next winter, we experimented with 18th century fabrics and fashions. After all, there was no central heating in the 18th century, so clothes must have been warmer right? Wrong. We found 18th century inspired clothing to be just as ineffective against the cold as their modern equivalents and came to the conclusion that the well known fashions of that era were by and large a mere statement of personal wealth: i.e. the frock coat, waistcoat and breeches were an outward reminder to people that the wearer could afford to buy over 200 cubic meters of wood a year to heat a house like ours, as well as the servants to keep the fires stoked.

The next winter, we went further back to a time contemporaneous with the building of our house: the late medieval period. After three freezing cold winters' worth of experimentation and with the discovery of just two principle items of clothing, finally we hit the 'heat your body not the air around you' jackpot. The first of the two items was an ankle length, long sleeved medieval-styled house coat and the second was a four cornered 'Erasmus' styled soft hat.

The design of each of these two items proved to be so efficient at heat conservation and so incredibly versatile, that we now wouldn't wish to face a winter without them.

The Coat

After a few attempts with wool, we turned to a double thickness recycled fleece, with a plain exterior and a mock sheepskin interior. It is a wonder fabric: light, easy to wash and relatively quick and easy to dry. The cut of the coat is 'A' shaped, being narrow at the top of the shoulders and very full at the ankles (at least as wide as the wearer is tall and then some). The sleeves are worn long and relatively narrow at the wrist. We added hoods to the coats instead of collars and snap fasteners every few centimeters to the full length of the front. The hoods come in handy on really cold nights for the same reasons as the hooded chair in the article: they block out the cold from behind and capture any heat escaping from the neck of the coat. In effect, the coats have the appearance of a cross between a monk's habit (when fully closed) and a medieval knights' watch coat (when opened or buttoned only at the neck).

The 'A' shape, effectively channels all your body heat upwards and back toward your body. This effect is something you have to experience in order to fully appreciate. Body temperature can be very precisely regulated by opening and closing fastenings up to the waist, up to the neck or leaving the coat completely open (a loose clasp is very useful across the neck for temperatures more suited to a cloak rather than a coat). The full shape is also very comfortable to walk around the house in; as comfortable as pajamas and not at all like wearing a coat indoors, even over other clothes.

The Hat
My wife finds the hood of her coat enough insulation in cold weather without a hat, but not blessed with her thick head of hair, I need a little extra help with 'loft' insulation. In general, I'm not a happy hat wearer; I usually find them too tight or too hot or just generally disagreeable. But from studying medieval paintings, I worked out how to make the four-cornered 'Erasmus' style soft hat and found its design to be absolutely brilliant: comfortable, versatile, extremely effective; the perfect compliment to the long coat.

The hat can be worn in up or down positions. When down, the ears are covered by flaps and the back edge is somewhat lower than in the up position. I find that the down position is only needed when the air temperature is at or below zero degrees centigrade - frosty mornings for example. Each ear flap has a leather strap attached, which ties loosely across the top of the head to keep the flaps and neck warming section 'up' when it is not quite as cold. Again, I experimented with wool lined with flannel (which was very nice but awkward to wash and dry) but soon substituted that for a plain, good quality recycled fleece, lined with polyester.

These two items are the key items of our 'heat yourself' solution, though they still need to be used in conjunction with other clothing. Also a source of external heat is still necessary; we have found it impossible to do away with heating altogether. For a start, when the temperature falls below 10 degrees Celsius for a prolonged period of time, there definitely seems to be an increased risk of illness and infection, probably caused by breathing in cold air. Some of this can be alleviated by wearing a scarf which loosely covers the chin and mouth (to work in my unheated studio I made several loops out of silk scarves, which slip over the head and sit around the neck). The scarf has the effect of 'recycling' some of the air you breath out, mixing warm exhaled air with cold fresh air and generally raising the temperature of the air you are breathing.

For the sake of our happiness, we still light a log fire (log burner) all winter, but in just one double room. Our consumption has fallen to around six cubic meters of wood per winter. At this level of consumption, we can maintain between 10-15 degrees Celsius, even during prolonged periods of freezing weather, in a space covering forty square meters with a ceiling height of just over three meters. In combination with our medieval style clothing, this is very comfortable for us. Luckily, our guests love dressing up in the extra coats and hats we have made when they come around for dinner, so we haven't suffered socially either (though people do tend to come to us more in the summer and invite us to them a little more often in the winter!).

Versatility:
In the cold early Spring and late Autumn, wearing the long coats around the house is enough to make the house feel 'heated' even without an extra fire, extending the feeling of living in a warm house well into another season. The fullness of the coat means that it is also big enough to use as a sofa 'throw' when spread out.

To sum up, I have worked all day, day after day, very comfortably in an unheated studio, where the ambient temperature was well below zero degrees Celsius wearing the following items:

1.Erasmus hat (fleece, flaps down)
2.Long coat (fleece, mock sheepskin inner)
3.Neck loop (warming the air that you breathe - silk)
4.Commercial thermal base layer.
5.Pajama shirt (flannel)
6.Sleeveless jerkin (knee-length, round-necked garment, straight-cut or 'A' line, any warm material (recycled fleece is the easiest and lightest)).
7.Warm trousers.
8.Warm socks
9.Leather shoes.

Although I've experimented very successfully with a full medieval 'kit', for the sake of not appearing to be insanely eccentric when anyone rings the doorbell, I find that the coat and hat work well with well layered modern clothing and using snap fasteners on the coat means that they can be removed quickly if needed!

Finally, even if you hate the idea of living like this forever, you should not underestimate the feeling of liberation when you know that you can make clothes which, by their ancient and brilliant design, will help you comfortably to survive a freezing cold winter.

I hope this has been useful.

Robert Bean

(17)

Thanks for referencing our research on ancient radiant heating systems. For those interested, Part II covers Europe and North America including discussion on the Romans, F.L. Wright, Wm. Levitt and some radiant heating history in Civil War hospitals.

George

(18)

Radiant heating based on pipes and oil, mounted close to the floor, regulated by pressure servo-valves is quite efficient, in terms of energy consumption. The downside of it, however, is that copper and steel piping are quite expensive. I don't think we should stay covered in thick layers or uncomfortable clothing, but we should rather downsize, or re-chamber our space of living, and heat only what we use.For new homes, I think people should start thinking about geodesic dome-style rooms for a stand-alone complex, and hexagonal shaping for apartment buildings. By the way Kris, I really loved the article on wind-powered factories. But do you know if there are any manufacturers of processing windmills ? If so could you send me the details, because I would like to try and collaborate with them for a sustainable developing project. Thank you !

Fred

(19)

Kotatsu are still very popular in Japan.

David Eastham

(20)

I understand the average UK heating bill is now £600. Most heat will be used during the winter quarter, say about 100 days from December to march, which means probably £6 to keep warm during cold nights.

Now £6 is roughly the price of two English pints of beer. You can probably see where I am taking this argument - yes - down the pub. Go out and you no longer need to heat the house.

Which is of course what men used to do in the old days. They would leave the wife and kids in front of the fire and go drinking. I think high energy costs should benefit struggling British pubs. So many people today live on their own, and this means when they are out the house the heating can be switched off.

Extending the idea of migration within the house to the heat source, as mentioned in the essay, might be migration to a more easily heated communal building.

Whilst central heating makes it easy to practice hobbies or pastimes in the spare room away from the rest of the family, a more energy efficient solution can be to practice your hobby amongst other like minded people in a clubhouse. Unfortunately the trend for socialising over the internet rather than with other people leads to the opposite!

Thanks for another of your typically holistic summary of a technology! I might note however in the 8th paragraph: "Radiant energy is transferred through electromagnetic waves, similar to light or sound". Of course sound is not an electromagnetic wave, unless it is a radio broadcast!

Ellen Anderson

(21)

@ John Parker: could you possible post a photo and/or patterns? I really enjoyed your response. I spent my last nickel on a site built masonry stove and it is wonderful but sometimes I want to be away from it and I, too, have been trying to figure out which materials are the best. I have hooded capes but I would like something with sleeves. I imagine I can find a patter for an erasmus hat online, right?

Leslie Jackson

(22)

Wonderful piece. I like it's entrance, defining Convection, Conduction and Radiation.
I wanted to flesh out a comment above, with thanks to Russel, who mentions a Dutch guy. He might be talking about Flemming Abrahammson of Fornyet Energi, in Denmark, though Danish, not Dutch: http://www.fornyetenergi.dk/
I'm Leslie Jackson, co-author of Rocket Mass Heaters, the book: www.rocketstoves.com

Ben

(23)

I can't find the next part of this article. Is it out yet?

Kris De Decker

(24)

@ Ben

Still working on that -- and it will be two more articles. Sorry for the delay.

Ben

(25)

Even better. I look forward to reading it.

YourNameIsRequired

(26)

> The Japanese had their "kotatsu", a movable low table with a charcoal heater underneath.

As someone else said above, kotatsu are still very common in Japan today, since homes are often badly insulated (they have to be light enough to withstand earthquakes) and Japan has to import pretty much 100% of its energy since the accident in Fukushima.

https://en.wikipedia.org/wiki/Kotatsu

Hilton Dier

(27)

A lot of these old design solutions were necessitated by the fact that people in earlier times didn't have access to decent insulation, windows, and air sealing technologies. Big radiant heat sources were essential in leaky uninsulated houses.

An architect I teach with has pointed out that radiant floor heating is pointless in a properly designed and built passive solar house. If you combine a well sealed and insulated building envelope with appropriately sized and located mass and south facing vertical glass you can have a comfortable interior space with little additional input. The air temperature will stay within a relatively narrow range and the interior surfaces will stay at a comfortable radiant temperature.

I'm all for low tech where it works best, but I advocate the use of modern double or triple paned windows with engineered frames, high-R insulation, and durable thin films and sealants in buildings. Just like I'd advocate for modern sanitation over bleeding and cupping. Build (or renovate) a house so that it passively supplies, stores, and preserves its own heat.

Kris De Decker

(28)

@ Hilton

That's basically what I'm saying in the third article of this series: http://www.lowtechmagazine.com/2015/03/local-heating.html

For new buildings, the design and the orientation are much more important factors for energy efficiency than the choice of the heating system, if that's needed at all.

However, we have a large supply of existing buildings that can't be redesigned in such a way, or only at high costs. For those buildings, local heating is a low-cost and low-tech solution that can save a lot of energy and improve thermal comfort.

john parker

(29)

@Ellen Anderson
Sorry for the great delay but I actually sold my house the day after you posted and have been on the road looking for a new one ever since! I've found my ideal low tech sustainable house and land project now, but have months of renovation ahead without access to my hard drive and therefore the ability to post the patterns you requested.
However, the book 'the Tudor tailor'has a pattern for a long gown which is virtually identical, save the collar instead of a hood. The end result looks like the king's gown in the woodcut illustration above, but with tapered, renaissance style sleeves. I experimented with broad sleeves, thinking they'd be useful to keep your hands warm, but in fact, unless you're a king sitting around all day, I found the tapered sleeves much less of a nuisance and more importantly- warmer!
The pattern for the Erasmus hat is an interesting maths problem. To give you a clue, you only need a pattern for one quarter of the crown plus the ear flap band :-).
With a bit of luck, I should be in a position to post a link to the patterns before next winter. Until then, have a great summer!
John Parker

Gerald Goldberg

(30)

Hi,

In winter I put quilts on the windows and they keep the cold from coming into the rooms! I also put a quilt on the front and back door.

dan

(31)

i love your site. fascinating stuff! keep up the good work. i also love the comments from your base of very informed and helpful folks. peace

Alison Cowan

(32)

I haven't read through all the comments, so please forgive me if I'm repeating someone.

I just wanted to point out that in the days when people were heated instead of spaces, getting wet could kill you.

If you get wet and can't get dry, you will die. If you get wet and it's cold and you can't get dry quickly enough, you will die very soon.

Hats are great. But so is insulation.

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