Tubes SolarSelection of Heat Storing Materials

Over View

• Tube solar is the conversions of sunlight into renewable energy for water heating , using a solar thermal collector solar water heating (SWH) comprise technologies that are used world wide increasingly

Solar water heating system(SWH)

• SWH systems were discovered in 19th century• Greece, Cyprus and Spain the leaders in the use of

SWH systems, with 30-40% of homes using them

• Here, in Jordan the cost of SWH system is about

900

Heat storing materials take heat from Sun light and pass it to water

Selection of materials

Selection of heat storing material

• Function: heat storing medium

• Objective: maximum heat storing per unit cost

• Constraints: heating time ~ 10 hours maximum temperature ~ 65 �

• Free variables: material choice

Material index calculation• Heat content Ԛ= wˑρ Cp ΔT

Where w: thickness of layer

Cp: heat capacity

• Thermal diffusivity a= (w^2) / 2t where t: time

• Ԛ= (2t)^2 ΔT (λ / a^0.5)

• Only λ and a are variables, then the material index (MI) = (λ / a^0.5)

comment COST/m^3 MI’S MATERIALS

Expansive, it may be used as constituent

1900 JD 387.3 PMMA

Suitable, available and efficient

900JD 395.3 Paraffin

Not suitable, used in construction of heat

storage walls

980 JD 1000 Brick

Final material choice

Design of tubes solar

paraffin compound CnH2n+2

• Paraffin hydrocarbon, also called alkane, any of the saturated hydrocarbons having the general formula CnH2n+2, C being a carbon atom, H a hydrogen atom, and n an integer.

• The paraffin's are major constituents of natural gas and petroleum.

Heat storage material

• A heat storage material may prepared from expanded vermiculite (EVM) and paraffin by vacuum impregnation.

• The latent heat approximately 135.5 J/g at the melting temperature of 48.0°C, when the paraffin content was 67%.

• The composite exhibited excellent thermal stability and has potential application in solar thermal energy storage and solar heating.

References

1- Material selection in mechanical design, Michael F. Ashpy.

2 -Review on thermal energy storage with phase change materials and applications, Atul Sharma.

3- Internet network, Wikipedia and other sources

MATERIALS ENGINEERING DEPARTEMENTMATERIALS SELECTION AND DESIGN

Name of Students:Mohammad A. Al- AjaramahSuhaib A. Ibrahim Mohammad

Instructor:Dr. Sami Massadah