Task 39

Examples

A large potential for innovative development of components and systems by using polymers is expected in the solar thermal industry as successfully demonstrated in other industry sectors, e.g electro- and electronic, automotive- building and construction and packaging industry. Examples of polymeric materials in solar thermal applications are shown below.

Swimming Pool Absorbers

Unglazed pool absorbers in polymeric materials have been successful in the market for more then 20 years. The examples show (from left to right) pool absorbers of (a) polypropylene, (b) ethylene propylene diene monomer (EPDM) rubber, (c) polyvinyl chloride/polyurethane (PVC/PU) covered polyester texture, (d) polyethylene pipes and (e) EPDM pipes in red in order to match the colour of the roof tiles.

ABOVO (AT), MEA Solaranlagen (AT), TEXSUN, (S), PIPELIFE Austria (AT), MAZDA Solar (D)

Glazed Absorbers

Presently there exists only few commercial polymeric absorbers with glazing (collector cover) mostly designed for low-pressure systems. The figures below show a thermosiphon system with absorber in polyethylene (PE) (left). Middle and right: Flat-plate collectors, with polycarbonate (PC) twin-wall sheets as collector cover. Middle: The absorber is made of silicone rubber tubing partly compressed between metal plates. Right: Drain-back collector with stiff, extruded absorber plate of polyphenylene ether/polystyrene (PPE/PS) blend.

Solco (AUS), Solartwin (UK), Solarnor (N)

Collector Cover

Rather common and know from the building and construction sector are twin-wall sheets of polycarbonate as collector cover (left). Other designs are (from left to right) dome structures of polycarbonate, corrugated, twin-walled polycarbonate roof sheets and acryl glazing.

Kaysersberg Plastics (F), Imagination Solar Limited (UK), Eternit-Werke (AT), Stiebel Eltron (D)

Roth-Werke(D), Buderus (D), Fasalex (AT)

Frame/Casing

Collector casing in acrylonitrile butadiene styrene (ABS) (left), with glasfiber reinforced plastics frame (middle) and wood plastic composites (right).

Integrated Storage Collectors (ICS)

Left: ICS with polypropylene casing and transparent insulation of cellulose triacetate; right: ICS with molded storage container in polyethylene and glazing in polycarbonate

Solarpower GmbH (D), Davis Energy Group / Sun Earth (US)

Consolar (D), ROTEX (D), HAASE Energietechnik AG (D)

Heat Stores

The examples to the left and middle show heat storage tanks in polypropylene (PP); left: The housing for heat exchanger and stratification-manifolds are also of PP; middle: The heat exchanger for the domestic hot water loop are in cross-linked polyethylene (PEX); right: storage tank in fibre glass reinforced polyester resin (FRP)

Seasonal Heat Stores

Gravel-water pit heat store, 1050 m³ pit, with 2.5 mm HDPE-liner (left) and borehole heat exchangers in polyethylene.

ITW-University of Stuttgart (D), REHAU (D)

Components in Solar Heating Systems with Advanced Functions

Hydraulic “printed circuit board” for the pump station in solar combisystems in polyphenylene sulfide, over-moulded header of pool collectors in polypropylene, stratifying unit in a heat store and special collector fitting for easy installation.

Clipsol (F), Heliocol (US), both Solvis (D);