It is already mentioned in this blog that large cellular boards can be used as thermal insulation and also as construction material, giving the stability of the wall. Especially in the passive housing market, this can be important. Today, we have two examples in Europe, where people on their own initiative started to use cellular glass as stability element and thermal insulation.
In this system, cellular glass is used in combination with brick slices by Clean Tech Block.
A passive housing U-value can be reached with normal wall thickness (< 400mm) and cellular glass, directly foamed from recycled glass. In the following system, cellular glass is used in combination with wood by Tebit Oy, Finland.
It is clear that the future is great for not expensive large boards cellular glass like today produced by GLAPOR cellular glass.
BELGLAS is still convinced that there is a market for open cell cellular glass. Acoustic absorption is one application, hydroculture a second like already demonstrated in a post about Growstone.
At GLAPOR, some possibities with open cell cellular glass boards were investigated …
I guess we eat today the first GLAPOR tomato …. The cellular glass perfectly controls the the stability of the root and the water and mineral content the plant gets to absorb …
Flat solar collectors to heat water have still a large future with an efficiency up to 85% compared with photovoltaic, which is still only 15%. A typical solar collector consists of a glass pane, which allows transmission with minimum refelection of sun radiation on fluid cooled heat exchanger, which is thermally insulated at the backside. This insulation will be mineral because temperatures above the glass temperature of polystyrene (90°C) or another polymer can be expected.
Cellular glass as thermal insulation was out of the question due to price and dimensions. Indeed, 0.60 x 0.45m boards for solar collectors of 2m x 1m are difficult to use. In the picture, the heat exchanger tube is put on mineral wool in an Al casing for only 245€ VAT included. The efficiency of this cheap solar collector is 75% (cold fluid at entrance) and without fluid flow, the temperature may become up to 208°C. With water, we could attain a pressure of 20 bar in that case, which means we need for example ethyleen glycol (EG) or propyleen glycol (PG) as safe liquid. They have a high boiling point (EG=197°C; PG=188°C) and low freezing point (EG=-12.9°C; PG=-59°C). With a fluid flow rate of 100l/hour, we have a pressure drop of 50 mbar.
For that reason, we could consider to replace the mineral wool with meander tube by a large GLAPOR cellular glass board with the meander channel, milled directly into the cellular glass. The glass cover (eventual a double pane) closes the channel at the top. In this case, the radiation is absorbed directly into the water reducing the temperature gradient between solar radiation aborber and water. This means that the water will be warmer in winter reducing the need for extra heating.
However, this idea is not new. Patent DE102014007805A1 from end 2015 describes exactly the above.
However, an earlier PatentanmeldungWO2012093062A2 (2011) describes also such a system based on foamed glass from recycling glass.
This patent was based on research, sponsord by the German government and performed at the Univerity of Freiberg. This is the second time we met this university in the cellular glass world. It was first with vacuum cellular glass and now with a solar collector.
A solar collector based on large cellular glass boards with the above structure should be much cheaper than the standard equipment, which is today used with a higher efficiency. Cellular glass is heat absorber, thermal insulation and casing at the same time. The difficult problem will be the connection of these cellular glass channels to metal tubes to be able to connect the solar collector on the system. But this problem can be solved with one of the many adhesives on the market. The major problem, the avialability of large cellular glass boards 2.8 x 1.2m is already solved by GLAPOR cellular glass.
This topic is maybe not the most challenging, but it is very important. According to the Swiss ECO-scarcity method (UBP), the transport of raw materials and cellular glass is responsible for 20 % of the total damage to the environment due to production, transport and installation of the cellular glass. In other words, 20% of the UBP is caused by transport. It is clear that efficient packing becomes very important.
Forty years back, 40mm cellular glass boards were the standard while today 140mm is the most popular thickness. Transporting 40 mm boards horizontally is a risky operation while this seems logic for 140mm boards. As a consequence, the cellular glass world started to transport vertically. The internal trailer height is maximum 3m with 2.45m internal width to be used with exchangeable EUR-pallets or thinner single use versions. A typical trailer has a floor for 33 pallets, which can be double stapled in the case of cellular glass.
In case of vertical stacking, the boards have a width of 450mm (height when stacked) and 600 mm length (half pallet length). Six parcels have than a total height of 2.70m which should become 2, 984m theoretical total height with two EUR-pallets (144mm height) to be installed in trucks with internal height between 2.85 and 3m. This is not possible and for that reason thinner and weaker pallets are used for this application to gain about 10 cm tolerance. However, these pallets cannot be exchanged because they are not designed to carry 1500 kg. In case of horizontal stacking, exchangeable EUR-pallets can be used because height is not critical anymore. Two pallets stacked have to respect a 2.80 m limit to allow loading the trailer. This means that a trailer can be maximally loaded with 79m³ cellular glass.
In case of vertical transport, the pallets have a fixed height with thinner pallets and I assume that slightly more cellular glass can be loaded, improving the UBP-score due to transport with I guess 4%. But using single use pallets instead of exchangeable EUR-pallets is responsible for an increase of 3.5% UBP. On the other hand, a width of 450 mm (vertical transport) instead of 800mm induces more joints after installation and so a decreased thermal resistance. Joints between 0.6 x 0.45m boards are responsible for 5% heat leak , which means that 0.8 x 0.6m boards should leak 3% in the joints.
At the end, vertically stacked or horizontally stacked boards are nearly equivalent if we speak about ecology. The choice depends on the requested dimensions and it looks that larger dimensions (thickness and length) are becoming more popular. Therefore, I guess that horizontal transport with EUR-pallets will be the future on the condition that the EUR-pallets are not covered by hot bitumen on the roof.