Evacuated Tube Solar Collector

The evacuated tube solar collector works by absorbing solar energy in the form of UV rays and converting it into thermal energy. An evacuated tube solar collector contains a number of evacuated tubes. Each evacuated tube is responsible for independantly absorbing the sun's radiation that reaches it.

Evacuated Tube Solar Collector

An evacuated tube is made up of 2 layers of strong borosilicate glass that are joined together. There is a vacuum in between the 2 layers of glass. This layer of vacuum allows the tube to retain its heat once it is gathered. The UV rays are absorbed by an absorbing film which lies in between the 2 layers of glass on the inside layer. This special absorbing film absorbs more than 92% of the UV rays that incident the tube and rejects less than 8% back to the atmosphere.

The heat is transferred by conduction to a copper fin inside the inner layer of glass. A heat pipe that is inserted into the fin absorbs this heat and transfers it to the copper header at the top of the collector. The heat pipe is a thin copper tube which contains a small amount of acetone. Once the heat pipe is subject to a small amount of heat the acetone vaporizes and turns into steam. It then rises to the top of the heat pipe where it reaches a condenser. Once the heat is removed from the condenser by a heating fluid such as water or a mixture of water and glycol, the acetone reverts to a liquid and returns to the bottom of the heat pipe where it repeats its cycle.

The condenser is inserted into a copper manifold where the heat is transferred to the heating fluid passing through the manifold. A manifold is a copper pipe with a set of sleeves distributed along its length. Each sleeve receives the condensing end of a heat pipe. At this intersection the fluid flowing through the manifold absorbs all the heat from the condenser and continues through the manifold.

Solar Heating Collector Manifold

The heat pipe and the copper fin are placed inside the evacuated tube where they are protected from the elements and are not able to emit heat via conduction or convection to the atmosphere, only to the copper header. This gives the evacuated tubes their high efficiency. This also allows the evacuated tube solar collector to out perform any other solar collector on the market.

Benefits Over Other Solar Collectors:

Snow falls in between the tubes and thus does not cover the collector
The collectors do not sit flush on a roof and thus do not affect the life of the roof
The tubes do not get hot; thus the captured energy is not lost to the atmosphere
Due to their high efficiency, less collectors and roof space are required
The collectors are very easy to install
Life span is more than 20 years
Not affected by temperature and thus can operate in the coldest climates
Evacuated tubes promote solar tracking

Specifications:

Model Number	SSC-10	SSC-15	SSC-20	SSC-25	SSC-30
Number of Tubes	10	15	20	25	30
Dimensions & Weight
Length (m)	2	2	2	2	2
Width (m)	0.83	1.21	1.58	1.95	2.33
Height (m)	1.35	1.35	1.35	1.35	1.35
Gross Area (m2)	1.67	2.42	3.17	3.92	4.67
Aperture Area (m2)	0.95	1.43	1.92	2.40	2.88
Absorber Area (m2)	0.83	1.24	1.66	2.07	2.48
Weight Kg	37	54	70	85	106
Materials
Glass	Borosilicate Glass (1.6mm thick)
Frame	Anodized Aluminum (18mm thick)
Insulation	Rockwool (50mm thick)
Heat Pipe & Manifold	Copper
Absorber
Evacuated Tubes	Tri-Target Vacuum Tubes
Tube Length	1.8 m
Outer Tube Diameter	58 mm
Inner Tube Diameter	47 mm
Absorbing Coating	SS-AL-N/Cu
Vacuum	P ≤ 5.0X10-3 Pa
Heat Pipe Condenser Ø	22 mm
Heat Pipe Length	1.7 m
Heat Pipe Thickness	0.8 m
Absorption	≥ 94%
Emmittance	≤ 6%
Stagnation Temperature	≥ 200 C
Average Heat Loss	≤ 0.7 W/m2 C
Operating Pressure	1.0 Mpa
Average Efficiency	77%
Limited Warranty	3 Years
Estimated Life Span	20+ Years