Solar Cooking
Last edited: 26 November 2023      
SLiCK SM70 photo, 8-19-15

The SLiCK SM70 is another example of an evacuated tube style solar cooker.

With the advent of relatively inexpensive evacuated glass tubes manufactured in China, it has become practical to use them in creating Evacuated tube solar cooker designs. The first such use was apparently Alex Kee in Malaysia, who demonstrated such a cooker at the Solar Cookers and Food Processing International Conference (2006) in Granada, Spain. Such tubes were originally produced as a component of popular solar water heating systems. Evacuated tube literally means that the cooking chamber is constructed of two layers of blown glass in the shape of a sealed tube, where the air has been removed between the layers.

Heat loss happens primarily by conduction and convection through a medium. With no air between the layers of glass the chamber is highly insulated, well suited for retaining cooking heat. The chamber is so effective it often does not require a large reflector to capture sunlight. One end of the tube is left open to allow a slender cooking tray to be inserted. The tray has a handle that seals with a gasket against the glass tube. The opposite end is fitted with a fixed stopper or has had the tube sealed during the manufacturing process. Improvements in glass technology is allowing for larger diameter tubes to be fabricated, which will allow for the use of larger cookware.


Evac tube relfectors, Stwart Maclachlan, UK, 8-17-23

Evacuated tube solar cooker with recycled fluorescent reflectors, Photo credit: Stewart Maclachlan

  • August 2023: Clever recycling - Stewart Maclachlan, of SLiCK in the United Kingdom, is quite resourceful repurposing materials for solar cookers. In the adjoining photo he found discarded reflectors from fluorescent light fixtures, which had been replaced with LED units, and attached them to his wall-mounted evacuated tube cooker. Very weather resistant, the new reflectors perform well according to Stewart.
SV The Crooked Anchor chicken wings, 6-21-23

Chicken wings cooked on board a sailboat, Photo credit: SV The Crooked Anchor

  • June 2023: Sailing into chicken wings - Subscriber to the The Solar Cookers World Network facebook group, SV The Crooked Anchor, is an avid sailor, often at sea on extended trips. On a recent cruise he attached his evacuated tube solar cooker near the bow of his sailboat. Filled with chicken wings, the solar cooker prepared a delicious meal. In hot weather the crew appreciates keeping the heat out of the galley.
Jo Muller evacuated tube November 2019

Jo Muller of Australia has built an evacuated-tube solar cooker built into plastic toolbox.

  • November 2019: Jo Muller repurposed a plastic toolbox to use for carrying and support of the reflectors for his evacuated tube solar cooker.
Metal lined Rand Tube diagram, Oxford, 6-12-18

A metal-lined Rand tube - Dave Oxford & Stewart Maclachlan

  • June 2018: Prospects for a metal-lined Rand tube - One way of achieving this would be to make the inner tube from stainless steel while preserving the other elements of the design – the glass outer tube, the evacuated space between the tubes, and the selective coating on the outside of the inner tube. Such a design already exists, though not for cooking. Utility scale concentrated solar power plants deploy linear parabolic reflector troughs with evacuated collector tubes at their focus. These tubes usually contain heat transfer fluid at temperatures of up to 400 °C (752 °F). They are said to be very durable (Gordy Bishop, personal communication). They are similar in construction to evacuated tubes made entirely of borosilicate glass, except that the inner tube is constructed of stainless steel. Thermal expansion and contraction are accommodated by flexible bellows. Read Dave Oxford and Stewart Maclachlan's paper on Rand tube safety.
  • February 2016: Steam collection in evacuated tube cooking: Faustine Odaba from NAREWAMA, describes the behavior of steam inside a tilted vacuum evacuated tube.
  • August 2015: Solarmate is a recent product developed by the company of the same name. It is compact and easily carried. It has been designed more for quickly heating water for hot drinks.
  • August 2015: Evacuated tube observations and performance - Dave Oxford and Stewart MacLachlan
  • August 2015: The SLiCK SM70 is an evacuated tube solar cooker. With relatively large reflectors it is well suited for solar cooking in high latitude locations such as the United Kingdom where it was developed. It will cook well at other locations as well.


  • Usually compact, and can cook quite efficiently with relatively small reflectors
  • Contemporary designs have aesthetic appeal
  • The cooking chamber requires careful handling
  • Glass technology somewhat limits the size of opening of the cooking chamber

Possible tube breakage explanation[]

Dave Oxford writes: "We were puzzled by the 'vertical' breakages. They differed from the breakages sustained while the tubes were horizontal. In horizontal mode, the tube imploded and the glass dropped vertically, as you would expect, because of the vacuum. In vertical mode, heating water, they exploded - that is, the glass ended up a good distance from the cooker. Since writing the paper, we've revised our views about what accounts for this. We believe that there is a different mechanism at work - superheating. That is, in such a narrow tube, there is little opportunity for convection within the water column. Even large copper domestic water heating cylinders are known to stratify. So, we now think that some of the water near the bottom of the column reaches a temperature above 100 °C (212 °F), especially in full sun. When convection does occur, and as the pressure decreases as it rises through the column, it flashes abruptly to steam, causing an explosion. A similar thing happens when liquids are heated in microwave ovens, and localised heating occurs. I must stress that this is just our latest hypothesis, and we have no solid evidence to support this. It would be quite difficult to test. Meanwhile, we are wary of boiling water in a vertical tube, though heating to any temperature below boiling seems perfectly safe. Not sure what is meant by "the reality of vertical gradients when racking a vacuum tube vertically"


Audio and video[]

  • November 2023:

Global Maker Ivan Yaholnitsky, Lesotho, Evacuated Tube Box Oven-2

Construction method explained

  • July 2019: 

Solar Cooking with Go Sun Sport-Spaghetti At The Winter Solstice

Evacuated tube cooker works with standard thermos bottle to cook pasta

  • August 2018:

SUNWINGS - Bake Your Surprises in the trendy Solar Cooker


  • November 2017:
  • January 2017:

External links[]

All construction plans[]

All designs[]

  • See below:

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